Gamma-ray Burst 080310

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:38:20 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.081d {+14h 40m 19s} (J2000),
                 220.186d {+14h 40m 45s} (current),
                 219.440d {+14h 37m 46s} (1950)
GRB_DEC:          -0.166d {-00d 09' 55"} (J2000),
                  -0.200d {-00d 12' 00"} (current),
                  +0.049d {+00d 02' 55"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5801 [cnts]    Image_Peak=215 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       38006 [cnts]
BKG_TIME:        31061.36 SOD {08:37:41.36} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14535 TJD;    70 DOY;   08/03/10
GRB_TIME:        31078.64 SOD {08:37:58.64} UT
GRB_PHI:         158.26 [deg]
GRB_THETA:        27.79 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.60 [sigma]
IMAGE_SIGNIF:    7.40 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +1  +4  +0  +0 +65  +1 
SUN_POSTN:       350.95d {+23h 23m 47s}   -3.90d {-03d 54' 07"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.89d {+01h 27m 33s}  +13.89d {+13d 53' 23"}
MOON_DIST:       157.30 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.20, 52.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      217.72, 14.68 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 267.16,17.76 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:39:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.0566d {+14h 40m 13.5s} (J2000),
                 220.1616d {+14h 40m 38.7s} (current),
                 219.4159d {+14h 37m 39.8s} (1950)
GRB_DEC:          -0.1756d {-00d 10' 32.1"} (J2000),
                  -0.2105d {-00d 12' 37.6"} (current),
                  +0.0385d {+00d 02' 18.5"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.50e-09 [erg/cm2/sec]
GRB_SIGNIF:      8.12 [sigma]
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31167.85 SOD {08:39:27.85} UT,   89.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.26 261.35 243.53
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       350.95d {+23h 23m 47s}   -3.90d {-03d 54' 05"}
SUN_DIST:        130.65 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.90d {+01h 27m 37s}  +13.90d {+13d 53' 47"}
MOON_DIST:       157.33 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.16, 52.20 [deg] galactic lon,lat of the burst
ECL_COORDS:      217.70, 14.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:40:07 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.0566d {+14h 40m 13.5s} (J2000),
                 220.1616d {+14h 40m 38.7s} (current),
                 219.4159d {+14h 37m 39.8s} (1950)
GRB_DEC:          -0.1756d {-00d 10' 32.1"} (J2000),
                  -0.2105d {-00d 12' 37.6"} (current),
                  +0.0385d {+00d 02' 18.5"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       66 [cnts]
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31167.85 SOD {08:39:27.85} UT,   89.2 [sec] since BAT Trigger Time
CENTROID_X:      357.74,  raw= 358  [pixels]
CENTROID_Y:      276.83,  raw= 277  [pixels]
ROLL:            95.27 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -49.89
GRB_POS_XRT_Z:   130.69
IMAGE_URL:       sw00305288000msxps_rw.img
SUN_POSTN:       350.95d {+23h 23m 47s}   -3.90d {-03d 54' 05"}
SUN_DIST:        130.65 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.90d {+01h 27m 37s}  +13.90d {+13d 53' 50"}
MOON_DIST:       157.33 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.16, 52.20 [deg] galactic lon,lat of the burst
ECL_COORDS:      217.70, 14.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:40:14 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.0566d {+14h 40m 13.5s} (J2000),
                 220.1616d {+14h 40m 38.7s} (current),
                 219.4159d {+14h 37m 39.8s} (1950)
GRB_DEC:          -0.1756d {-00d 10' 32.1"} (J2000),
                  -0.2105d {-00d 12' 37.6"} (current),
                  +0.0385d {+00d 02' 18.5"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       66 [cnts]
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31167.85 SOD {08:39:27.85} UT,   89.2 [sec] since BAT Trigger Time
CENTROID_X:      357.74,  raw= 358  [pixels]
CENTROID_Y:      276.83,  raw= 277  [pixels]
ROLL:            95.27 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -49.89
GRB_POS_XRT_Z:   130.69
IMAGE_URL:       sw00305288000msxps_rw.img
SUN_POSTN:       350.95d {+23h 23m 47s}   -3.90d {-03d 54' 05"}
SUN_DIST:        130.65 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.90d {+01h 27m 37s}  +13.90d {+13d 53' 51"}
MOON_DIST:       157.33 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.16, 52.20 [deg] galactic lon,lat of the burst
ECL_COORDS:      217.70, 14.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:41:40 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.095d {+14h 40m 23s} (J2000)
POINT_DEC:        -0.164d {-00d 09' 50"} (J2000)
POINT_ROLL:      95.272d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31176.67 SOD {08:39:36.67} UT,   98.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.681
N_STARS:         49
X_OFFSET:        392 [pixels]
Y_OFFSET:        600 [pixels]
X_MAX:           1351 [pixels]
Y_MAX:           1559 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0098.fits
SUN_POSTN:       350.95d {+23h 23m 48s}   -3.90d {-03d 54' 03"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.92d {+01h 27m 40s}  +13.90d {+13d 54' 13"}
MOON_DIST:       157.30 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.22, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:42:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.095d {+14h 40m 23s} (J2000)
POINT_DEC:        -0.164d {-00d 09' 50"} (J2000)
POINT_ROLL:      95.272d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31176.67 SOD {08:39:36.67} UT,   98.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.681
N_STARS:         49
X_OFFSET:        392 [pixels]
Y_OFFSET:        600 [pixels]
X_MAX:           1351 [pixels]
Y_MAX:           1559 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0098.fits
SUN_POSTN:       350.95d {+23h 23m 48s}   -3.90d {-03d 54' 03"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.92d {+01h 27m 42s}  +13.91d {+13d 54' 21"}
MOON_DIST:       157.30 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.22, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:43:07 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.081d {+14h 40m 19s} (J2000),
                 220.186d {+14h 40m 45s} (current),
                 219.440d {+14h 37m 46s} (1950)
GRB_DEC:          -0.166d {-00d 09' 55"} (J2000),
                  -0.200d {-00d 12' 00"} (current),
                  +0.049d {+00d 02' 55"} (1950)
GRB_DATE:        14535 TJD;    70 DOY;   08/03/10
GRB_TIME:        31078.64 SOD {08:37:58.64} UT
TRIGGER_INDEX:   137
GRB_PHI:         158.26 [deg]
GRB_THETA:        27.79 [deg]
DELTA_TIME:      32.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.60 [sigma]
IMAGE_SIGNIF:    7.40 [sigma]
LC_URL:          sw00305288000msb.lc
SUN_POSTN:       350.95d {+23h 23m 48s}   -3.90d {-03d 54' 02"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.93d {+01h 27m 44s}  +13.91d {+13d 54' 35"}
MOON_DIST:       157.32 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.20, 52.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      217.72, 14.68 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 267.16,17.76 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:43:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.095d {+14h 40m 23s} (J2000)
POINT_DEC:        -0.164d {-00d 09' 50"} (J2000)
ROLL:            95.272d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31176.67 SOD {08:39:36.67} UT,   98.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     226831179
X_OFFSET:        613 [pixels]
Y_OFFSET:        1077 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       773
Y_GRB_POS:       1237
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0098.fits
SUN_POSTN:       350.95d {+23h 23m 48s}   -3.90d {-03d 54' 02"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.93d {+01h 27m 43s}  +13.91d {+13d 54' 33"}
MOON_DIST:       157.31 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.22, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:43:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.095d {+14h 40m 23s} (J2000)
POINT_DEC:        -0.164d {-00d 09' 50"} (J2000)
ROLL:            95.272d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31176.67 SOD {08:39:36.67} UT,   98.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     226831179
X_OFFSET:        613 [pixels]
Y_OFFSET:        1077 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       773
Y_GRB_POS:       1237
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0098.fits
SUN_POSTN:       350.95d {+23h 23m 48s}   -3.90d {-03d 54' 02"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.93d {+01h 27m 44s}  +13.91d {+13d 54' 39"}
MOON_DIST:       157.31 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.22, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:49:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.094d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 58"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31283.86 SOD {08:41:23.86} UT,   205.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.613
N_STARS:         59
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0205.fits
SUN_POSTN:       350.95d {+23h 23m 49s}   -3.90d {-03d 53' 56"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       21.99d {+01h 27m 58s}  +13.94d {+13d 56' 09"}
MOON_DIST:       157.34 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:50:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.094d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 58"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31283.86 SOD {08:41:23.86} UT,   205.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     226831286
X_OFFSET:        613 [pixels]
Y_OFFSET:        1077 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       773
Y_GRB_POS:       1237
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0205.fits
SUN_POSTN:       350.95d {+23h 23m 49s}   -3.90d {-03d 53' 55"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.00d {+01h 28m 01s}  +13.94d {+13d 56' 28"}
MOON_DIST:       157.35 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:51:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.094d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 58"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31283.86 SOD {08:41:23.86} UT,   205.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     226831286
X_OFFSET:        613 [pixels]
Y_OFFSET:        1077 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       773
Y_GRB_POS:       1237
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0205.fits
SUN_POSTN:       350.95d {+23h 23m 49s}   -3.90d {-03d 53' 54"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.01d {+01h 28m 02s}  +13.94d {+13d 56' 34"}
MOON_DIST:       157.35 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #7381
R. Chornock, R. J. Foley, W. Li, and A. V. Filippenko report that:
The Katzman Automatic Imaging Telescope at Lick Observatory slewed to the position of GRB 080310 and found a new source not present in the DSS:
14:40:13.81 -00:10:30.6
at about magnitude 17. The new object is detected in V, I, and unfiltered images starting at 14:40:20.04 UT. We suggest it may be the afterglow of GRB 080310.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:54:28 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 59"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31946.22 SOD {08:52:26.22} UT,   867.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.752
N_STARS:         53
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0867.fits
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 51"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.04d {+01h 28m 09s}  +13.96d {+13d 57' 26"}
MOON_DIST:       157.37 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:54:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 59"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31946.22 SOD {08:52:26.22} UT,   867.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.752
N_STARS:         53
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0867.fits
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 50"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.04d {+01h 28m 10s}  +13.96d {+13d 57' 33"}
MOON_DIST:       157.37 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:56:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 59"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31946.22 SOD {08:52:26.22} UT,   867.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     226831948
X_OFFSET:        612 [pixels]
Y_OFFSET:        1076 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       772
Y_GRB_POS:       1236
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0867.fits
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 49"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.06d {+01h 28m 15s}  +13.97d {+13d 57' 60"}
MOON_DIST:       157.38 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:57:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 59"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31946.22 SOD {08:52:26.22} UT,   867.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     226831948
X_OFFSET:        612 [pixels]
Y_OFFSET:        1076 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       772
Y_GRB_POS:       1236
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0867.fits
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 48"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.06d {+01h 28m 16s}  +13.97d {+13d 58' 07"}
MOON_DIST:       157.38 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #7382
J. R. Cummings (NASA/UMBC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), P. A. Evans (U Leicester), E. A. Hoversten (PSU), S. D. Hunsberger (PSU), C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 08:37:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080310 (trigger=305288). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 220.081, -0.166 which is
```
   RA(J2000) = 14h 40m 19s
   Dec(J2000) = -00d 09' 55"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a precursor at T-24 seconds and multiple peaks from T-10 to T+6 seconds. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 08:39:27.9 UT, 89.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 220.0566, -0.1756 which is equivalent to:
```
   RA(J2000)  = 14h 40m 13.5s
   Dec(J2000) = -00d 10' 32.1"
```
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 94 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to assess possible redshift constraints using X-ray spectroscopy and the nH-z relation from Grupe et al. (2007).
UVOT took a finding chart exposure of nominal 100 seconds with the White (160-650 nm) filter starting 99 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at
```
  RA(J2000)  =	14:40:13.80 = 220.0575
  DEC(J2000) = -00:10:29.6  =  -0.1749
```
with a 1-sigma error radius of about 0.6 arc sec. This position is 4.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.8 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:59:23 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.0575d {+14h 40m 13.80s} (J2000),
                 220.1625d {+14h 40m 39.00s} (current),
                 219.4168d {+14h 37m 40.02s} (1950)
GRB_DEC:          -0.1751d {-00d 10' 30.3"} (J2000),
                  -0.2100d {-00d 12' 35.8"} (current),
                  +0.0390d {+00d 02' 20.3"} (1950)
GRB_ERROR:       0.4 [arcsec radius, statistical only]
GRB_MAG:         18.39 +/- 0.50 [mag]
FILTER:          10, White
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31178.00 SOD {08:39:38.00} UT,   99.4 [sec] since BAT Trigger Time
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 46"}
SUN_DIST:        130.66 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.09d {+01h 28m 20s}  +13.98d {+13d 58' 40"}
MOON_DIST:       157.42 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.16, 52.20 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      217.70, 14.67 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:59:33 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     305288,   Seg_Num: 0
GRB_RA:          220.0580d {+14h 40m 13.9s} (J2000),
                 220.1630d {+14h 40m 39.1s} (current),
                 219.4173d {+14h 37m 40.1s} (1950)
GRB_DEC:          -0.1750d {-00d 10' 29.9"} (J2000),
                  -0.2099d {-00d 12' 35.5"} (current),
                  +0.0391d {+00d 02' 20.7"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31885.00 SOD {08:51:25.00} UT,   806.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       350.96d {+23h 23m 50s}   -3.90d {-03d 53' 46"}
SUN_DIST:        130.66 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.09d {+01h 28m 21s}  +13.98d {+13d 58' 42"}
MOON_DIST:       157.42 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.16, 52.20 [deg] galactic lon,lat of the burst
ECL_COORDS:      217.71, 14.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 09:01:23 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 10' 00"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  32053.29 SOD {08:54:13.29} UT,   974.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        2.362
N_STARS:         54
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00305288000msufc0974.fits
SUN_POSTN:       350.96d {+23h 23m 51s}   -3.90d {-03d 53' 44"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.10d {+01h 28m 25s}  +13.99d {+13d 59' 10"}
MOON_DIST:       157.40 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 09:01:50 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 10' 00"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  32053.29 SOD {08:54:13.29} UT,   974.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        2.362
N_STARS:         54
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00305288000msufc0974.fits
SUN_POSTN:       350.96d {+23h 23m 51s}   -3.90d {-03d 53' 44"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.11d {+01h 28m 26s}  +13.99d {+13d 59' 16"}
MOON_DIST:       157.40 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 09:02:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 10' 00"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  32053.29 SOD {08:54:13.29} UT,   974.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     226832055
X_OFFSET:        612 [pixels]
Y_OFFSET:        1076 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       772
Y_GRB_POS:       1236
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0974.fits
SUN_POSTN:       350.96d {+23h 23m 51s}   -3.90d {-03d 53' 42"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.12d {+01h 28m 28s}  +13.99d {+13d 59' 33"}
MOON_DIST:       157.41 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 09:03:23 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.093d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 10' 00"} (J2000)
ROLL:            95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  32053.29 SOD {08:54:13.29} UT,   974.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     226832055
X_OFFSET:        612 [pixels]
Y_OFFSET:        1076 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       772
Y_GRB_POS:       1236
BINNING_INDEX:   1
IM_URL:          sw00305288000msuni0974.fits
SUN_POSTN:       350.96d {+23h 23m 51s}   -3.90d {-03d 53' 42"}
SUN_DIST:        130.63 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.12d {+01h 28m 29s}  +13.99d {+13d 59' 40"}
MOON_DIST:       157.41 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #7383
[corrected UT time]
R. Chornock, R. J. Foley, W. Li, and A. V. Filippenko (UC Berkeley) report that:
The Katzman Automatic Imaging Telescope at Lick Observatory slewed to the position of GRB 080310 and found a new source not present in the DSS:
14:40:13.81 -00:10:30.6
at about magnitude 17. The new object is detected in V, I, and unfiltered images starting at 08:40:01 UT. We suggest it may be the afterglow of GRB 080310.
GCN Circular #7384
E. Berger (Carnegie/Princeton) and M. Rauch (Carnegie) report:
"We obtained a spectrum of the optical afterglow of GRB 080310 (GCNs 7381, 7382) using the MagE spectrograph on the Magellan/Clay 6.5-m telescope. From preliminary analysis we determine a redshift of about 1.7 based on broad Ly-alpha absorption at ~3300A. Further observations and analysis are on-going."
GCN Circular #7385
S. Covino, P. D'Avanzo, D. Fugazza, L.A. Antonelli, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on behalf of the REM team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 080310 on March 10 08:40:27 UT (about 150 seconds after the burst).
We detect the afterglow reported in GCN 7381 and 8383 (Chornock et al.) and GCN 7382 (Cummings et al.).
The object has H~14.5 at about 5 min from the burst time.
Further analyses and observations are in progress.
GCN Circular #7386
B. E. Cobb, part of the larger SMARTS consortium, reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 080310 (GCN 7382, Cummings et al.) beginning 20 minutes post-burst (2008-03-10 08:58 UT). Total summed exposure times amounted to 180s in BRIYJK and 120s in H and V.
The afterglow of GRB 080310 (GCN 7382, Cummings et al. & GCN 7383, Chornock et al.) is detected in our images. Preliminary comparison to USNO-B1.0 stars in I and 2MASS stars in J indicates the following afterglow magnitudes:
```
time post-burst         I mag           J mag
~25 minutes             16.3+/-0.2      15.9+/-0.2
```
The afterglow fades by ~0.4 magnitudes in I between 25 and 45 minutes post-burst. This source is therefore confirmed to be the afterglow of GRB 080310, with a decay rate of alpha ~ -0.6.
GCN Circular #7387
P.A. Milne and G.G. Williams (U Arizona) report on behalf of the Super-LOTIS team:
The 0.6m Super-LOTIS telescope began R-band observations of the error region of GRB080310 (Swift trigger 305288) at 08:38:43 UT, 44 seconds after the start of the burst. The OT detected by Chornock et al. (GCN 7381) and confirmed by Cummings et al. (GCN 7382) is not apparent in the initial images, but is clearly visible in subsequent images. A stack of the initial 3x10s exposures does not detect the GRB, while subsequent single 20sec exposures do, suggesting that the GRB brightened during the first two minutes.
We used the USNO-B star at RA=14:40:11.3, Dec==00:10:40.6 (0898-0239265) to derive the R magnitude.
The R-band magnitude of the afterglow in the first image is:
```
UT Start   UT End ExpTime  R mag  error
Single
08:40:29  08:41:09 1x20s  17.97 +/- 0.18
08:41:03  08:41:23 1x20s  16.81 +/- 0.08
Stack
08:40:29  08:42:37 5x20s  16.91 +/- 0.04
08:43:24  08:54:27 10x60s 16.98 +/- 0.02
```
Observations are continuing. This message can be cited.
GCN Circular #7388
J.X. Prochaska (UCSC), M. Murphy (Swinburne), A.L. Malec (Swinburne), K. Miller (Lick) report on behalf of GRAASP:
"We observed the afterglow of GRB 080310 with the Kast dual spectrometer for a series of 900s exposures starting at UT 09:06 under good conditions. Analysis of the red side reveals a series of strong absorption features (SiIV, CIV, AlII 1670) consistent with the redshift z=2.4266. At present we consider this to be the redshift of GRB 080310.
Further analysis is in progress."
This GCN may be cited.
GCN Circular #7389
E. Berger (Carnegie/Princeton) and M. Rauch (Carnegie) report:
"The redshift of 1.7 previously quoted in GCN 7384 was due to mis-identification of the line. Based on the detection of Ly-alpha, SII, CIV, SiIV, etc. the correct redshift is z=2.42."

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 10 Mar 08 08:49:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     305288,   Seg_Num: 0
POINT_RA:        220.094d {+14h 40m 22s} (J2000)
POINT_DEC:        -0.167d {-00d 09' 58"} (J2000)
POINT_ROLL:      95.273d
IMG_START_DATE:  14535 TJD;    70 DOY;   08/03/10
IMG_START_TIME:  31283.86 SOD {08:41:23.86} UT,   205.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.613
N_STARS:         59
X_OFFSET:        293 [pixels]
Y_OFFSET:        757 [pixels]
X_MAX:           1252 [pixels]
Y_MAX:           1716 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00305288000msufc0205.fits
SUN_POSTN:       350.95d {+23h 23m 49s}   -3.90d {-03d 53' 55"}
SUN_DIST:        130.62 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:       22.00d {+01h 27m 59s}  +13.94d {+13d 56' 15"}
MOON_DIST:       157.34 [deg]
MOON_ILLUM:      9 [%]
GAL_COORDS:      351.21, 52.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      217.74, 14.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #7390
P. Garnavich (Notre Dame), J. L. Prieto, R. Pogge (OSU) report:
We observed the position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) with the Large Binocular Telescope and LBC red and blue cameras starting at 9:04 (UT) (0.44 hours after the burst) and ending 1 hour after the burst. Observations were obtained approximately every minute. The initial pair of observations showed no significant decay, but then declined rapidly into a power-law with a decay index of 0.65 (see Cobb et al., GCN 7386).
This message may be cited.
GCN Circular #7391
P.M. Vreeswijk (DARK), P. Jakobsson (U. Hertfordshire), A.O. Jaunsen (U. Oslo) and C. Ledoux (ESO) report on behalf of a larger collaboration:
We observed the optical afterglow (Chornock et al., GCN 7381) of GRB 080310 (Cummings et al., GCN 7382) with the Ultraviolet and Visual Echelle Spectrograph (UVES) mounted at ESO's VLT Kueyen. Observations were triggered automatically in rapid-response mode starting on 2008 March 10 at 08:51 UT (13 min after the Swift trigger). We secured two epochs over the full UVES wavelength range before morning twilight.
Most absorption lines can be explained by three systems at redshifts z=2.43, z=2.28, and z=1.67, confirming the probable redshift of GRB080310 first reported by Prochaska et al. (GCN 7388).
We acknowledge excellent support from the observing staff at Paranal, in particular Dominique Naef and Claudio Melo.
GCN Circular #7392
J. L. Prieto (OSU), P. Garnavich (Notre Dame), R. Pogge (OSU) report:
We continue to observe the afterglow of GRB 080310 (Garnavich et al., GCN 7390) with the LBT and LBC blue/red cameras. Data taken between 1.7 and 2.1 hours after the burst show a steepening decay rate. The power-law decay index over this period was 1.01 suggesting a break in the light curve is underway.
This message may be cited.
GCN Circular #7393
S. Covino, G. Tagliaferri, D. Fugazza, G. Chincarini, on behalf of the MISTICI collaboration report:
We observed the field of GRB 080310 (GCN 7382, Cummings et al.) with the VLT equipped with FORS2 with the Rapid Response Mode starting from 2008-03-20 at 08:42:59 UT (about 5 minutes from the burst) for almost one hour of continuous observations. The optical afterglow (GCN 7381, Chornock et al.) is well detected and it was brighter than R~17 (compared to USNO stars) already in the first frame.
A complete analysis is in progress.
GCN Circular #7394
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 99 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080310, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 220.05801, -0.17496 which is equivalent to:
```
RA (J2000): 14h 40m 13.92s
Dec (J2000): -00d 10' 29.9"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #7395
T.W. Chen, L.C. Huang, K.Y. Huang and Y. Urata on behalf of EAFON report:
"We have been monitoring the optical afterglow of GRB080310 (GCN #7381, 7382) using Lulin 1m telescope. The brightness in R-band at 15:40 (~7hrs after the burst) is ~20 mag. Continuous optical monitoring is encouraged."
Further observation and analysis are in progress."
GCN Circular #7396
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB080310 prior to the burst. As these data should be useful as a pre-burst comparison and for calibrating photometry, we are supplying the images and photometry measurements for this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and 3 files of photometry and astrometry, are being placed at http://mizar.as.arizona.edu/~grb/public/GRB080310
We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=220.081 (14:40:19.4), dec=-0.166000 (-00:09:57.6); Swift-BAT TRIGGER 305288), as well as 3 gri color-composite JPGs (with different stretches). The units in the FITS images are nanomaggies per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie is a flux-density unit equal to 10^-9 of a magnitude 0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS astrometric information.
In the file GRB080310_sdss.calstar.dat, we report photometry and astrometry of 486 bright stars (r<20.5) within 15' of the burst location. The magnitudes presented in this file are asinh magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars are not well-detected in the u-band; use the errors and object flags to monitor data quality.
In the files GRB080310_sdss.objects_flux.dat and GRB080310_sdss.objects_magnitudes.dat, we report photometry of 818 objects detected within 6' of the GRB position. We have removed saturated objects and objects with model magnitudes fainter than 23.0 in the r-band. The fluxes listed in GRB080310_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB080310_sdss.objects_magnitudes.dat are asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning that they are very close to AB zeropoints and magnitudes are quoted in asinh magnitudes. Photometric zeropoints are known to about 2% rms. None of the photometry is corrected for dust extinction. The Schlegel, Finkbeiner, and Davis (1998) predictions for this region are A_U=0.202 mag, A_g=0.149 mag, A_r = 0.108 mag, A_i=0.082 mag, and A_z=0.058 mag.
The file GRB080310_sdss.spectro.dat contains a list of the 3 objects with SDSS spectroscopy within 6 arcminutes of the GRB position. In addition to the redshift and 1-sigma error for each object, this file also lists the object spectroscopic classification.
SDSS astrometry is generally better than 0.1 arcsecond per coordinate. Users requiring high precision astrometry should take note that the SDSS astrometric system can differ from other systems such as those used in other notices; we have not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases can be found in our initial data release paper (Cool et al. 2006, PASP 118, 733). See the SDSS DR4 documentation for more details: http://www.sdss.org/dr5
These data have been reduced using a slightly different pipeline than that used for SDSS public data releases. We cannot guarantee that the values here will exactly match those in the data release in which these data are included. In particular, we expect the photometric calibrations to differ by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data release paper, Adelman-McCarthy et al. (2007, ApJS, 172, 634), when using the data or referring to the technical documentation.
GCN Circular #7397
J.X. Prochaska (UCSC), R.J. Foley (UCB), B. Holden (UCCS), D. Magee (UCSC), M. Cooper (Arizona) and A. Dutton (UCSC) report on behalf of GRAASP:
"We observed the afterglow of GRB 080310 (Chornock, #7381) with the Keck/DEIMOS spectrometer for a series of 900s exposures starting ~2hr after the burst under good conditions. Analysis of the data confirms the three absorption systems reported by Prochaska et al. (#7388) and Vreeswijk et al. (#7391). We identify modest strength FeII and MgII resonance lines associated with the absorber at z=2.4266 and also weaker FeII* absorption. The latter observation establishes this gas as the ISM surrounding GRB 080310.
Further analysis is in progress."
This GCN may be cited.
GCN Circular #7398
E. A. Hoversten (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 080310 (trigger 305288) starting 99 seconds after the BAT trigger (Cummings, et al., GCN Circ. 7382) starting with a 100s finding chart exposure in the white filter. A bright afterglow was clearly detected in the initial white and V band exposures.
Further analysis shows that a fading source is detected at the XRT position in the U, B, V, and white filter images. The source is still detectable in these filters around 7000 seconds after the burst. The white and U band images show a brightening of the source reaching a peak after 1 ks after the burst before fading smoothly. The B and V images show a more smooth decay.
The afterglow is not detected in the UVW1 and UVM2 filters and is weakly detected in the UVW1 filter. This is consistent with the measured redshift of 2.42 (Prochaska, et al., GCN Circ. 7388).
The detections and 3-sigma upper limits in the UVOT photometric system (Poole, et al. 2008, MNRAS 383, 627) are given in the following table. The white and optical magnitudes are individual exposures while the UV magnitudes are from co-added images.
```
Filter T_start(s) T_stop(s) Exposure(s)  Mag

white     99        197       98         18.50 +/- 0.06
white    868        967       98         17.95 +/- 0.05
white   6788       6985      197         18.99 +/- 0.07

v        208        602      393         17.38 +/- 0.05
v       7199       7334      135         18.5  +/- 0.3

b        685        695       10         17.7  +/- 0.2
b       6584       6780      197         18.9  +/- 0.1

u        660        680       19         17.8  +/- 0.2
u       1430       1450       19         17.3  +/- 0.2
u       6379       6575      197         18.3  +/- 0.1

uvw1     638       6373      452         20.3 +/- 0.3
uvm2     613       6168      197        >19.8
uvw2     716       7194      432        >20.8
```
No correction has been made for the expected Galactic extinction of E (B-V) of 0.04 mag in the direction of the burst (Schlegel, et al. 1998).
GCN Circular #7399
A.P. Beardmore, J.P. Osborne, R.L.C. Starling, K.L. Page, P.A. Evans (U. Leicester) and J.R. Cummings (NASA/UMBC) report on behalf of the Swift-XRT team:
The Swift-XRT started observing GRB 080310 (trigger no. 305288, Cummings et al. GCN 7382) at 2008-03-10 08:39:27.85 UT, 89s after the trigger. The observation so far spans 3 snapshots, with Windowed Timing mode data from T+95s to T+799s, and Photon Counting mode thereafter.
The best XRT position is the UVOT-enhanced position from Osborne et al. (GCN 7394).
At first, the 0.3-10keV X-ray light curve decays from 39 count s^-1 at T+95s to 18 count s^-1 at T+130s but then shows strong flaring activity. An initial rebrightening occurs from about T+135s to T+420s, reaching ~135 count s^-1 at approximate times of 200s, 250s, 280s and 350s after the trigger. This is followed by a second flare from T+500 to T+620s, where it reaches a maximum of ~115 count s^-1 at T+565s. Following the flaring activity, the X-ray light curve, thus far, shows a slow decline out to the end of the third snapshot (T+1.0ks to T+18.7ks), where it reaches a count rate of 0.1 count s^-1 with an underlying decay slope of alpha~0.5.
The X-ray data also show strong spectral evolution during the flaring intervals. A 1.5-10keV/0.3-1.5keV hardness ratio reveals the X-ray emission initially hardens from T+135s to T+200s as the light curve rebrightens, at which point it remains approximately constant until T+360s, before softening as the light curve decays. Similarly, the source hardens again during the second flare from T+500s to T+565s, then softens as this flare declines.
A spectrum of the WT data from T+200s to T+360s, where the hardness ratio is approximately constant, can be well fit by an absorbed powerlaw with photon index 1.45 +/- 0.02 and column density of (7.0 +/- 1.0)e21 cm^-2 at the redshift of the burst (z=2.43, Prochaska et al. GCN 7388; Berger and Rauch GCN 7389; Vreeswijk et al. GCN 7391), in addition to the Galactic column density of 3.3e20 cm^2 in this direction. The observed 0.3-10keV flux is (6.1 +/- 0.1)e-9 erg cm^-2 s^-1, which corresponds to an unabsorbed flux of 6.8e-9 erg cm^-2 s^-1. The counts to observed flux conversion factor at the time of this spectrum is 4.9e-11 erg cm^-2 count^-1.
The PC mode data from the second snapshot (T+5.1ks to T+7.3ks) show a softer spectrum, with a photon index of 1.9 +/- 0.2 and column density consistent with the value determined above. The observed 0.3-10keV flux at this time is (1.1 +/- 0.1) e-11 erg cm^-2 s^-1, and corresponds to a flux conversion factor of 4.7e-11 erg cm^-2 count^-1.
If the underlying powerlaw decay continues as is, we predict an XRT count rate of 0.05 count s^-1 at T+24hr, which corresponds to an observed 0.3-10keV flux of 2.5e-12 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular #7402
J. Tueller (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080310 (trigger #305288) (Cummings, et al., GCN Circ. 7382). The BAT ground-calculated position is RA, Dec = 220.040, -0.164 deg which is
```
   RA(J2000)  = 14h 40m 9.6s
   Dec(J2000) = 0d 9' 49"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%.
The mask-weighted lightcurve shows many peaks starting at ~T-60 sec. The main peak extends from ~T-12 to T+7 sec, then there is a period with no detectable emission, then a broad, weaker peak from T+180 to T+360 sec. The later peak corresponds to the first strong flare seen in the XRT (Beardmore et al., GCN circ. 7399). BAT sees no emission at the time of the second flare seen in the XRT, even though in the XRT energy range it was of similar intensity at the peak to the first flare.
The location of the burst entered the BAT field of view at about T-80 sec during a preplanned slew. It is possible that some very weak emission preceded that time, but the BAT raw lightcurve, which is partially sensitive to photons from outside the FOV rules out strong emission. T90 (15-350 keV) is 365 +- 20 sec (estimated error including systematics).
The time-averaged spectrum from T-71.8 to T+318.7 sec is best fit by a simple power-law model. The burst does not appear to have significant emission above about 150 keV however. The power law index of the time-averaged spectrum is 2.32 +- 0.16. The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+1.27 sec in the 15-150 keV band is 1.3 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/305288/BA/
GCN Circular #7403
P. Wozniak, W.T. Vestrand, J. Wren, and H. Davis (Los Alamos National Laboratory)
Our RAPTOR-S and RAPTOR-T telescopes began simultaneous multicolor (clear, V, R, I) imaging of GRB 080310 at UT 08:38:27.14, 28.5 seconds after the trigger, 6.7 seconds after receiving the trigger.
The counterpart identified by Chornok et al. (GCN 7381) brightened from below 17 mag to about 16.8 mag at ~200 seconds (clear band calibrated to USNO B1.0 R2 magnitudes) and dimmed to about 17.3 mag at 400 seconds. We clearly detect the OT simultaneously in all filters and follow its flux evolution for 1.5 hours. We observe a broad plateau between 400 and 1100 seconds with slight rebrightening towards the end of this time interval, folowed by rapid decay.
GCN Circular #7406
D. A. Perley, J. S. Bloom, and W. Li (UC Berkeley) report:
PAIRITEL responded to GRB 080310 and began taking data at UT 2008-03-10 09:04:58 in J, H, and K filters simultaneously. The afterglow (Chornock et al., GCN 7381) is well-detected in all three filters. We report the following magnitudes:
```
t_mid(s)  exp(s)  magnitude
1833      259     J = 15.63 +/- 0.03
1833      259     H = 14.94 +/- 0.03
1833      259     K = 14.29 +/- 0.03
```
Combining PAIRITEL data with 347 KAIT observations (calibrated to SDSS DR6) and the UVOT magnitudes reported by Hoversten et al. (GCN 7398), we generate a UV-through-IR spectral energy distribution interpolated to the midpoint of the PAIRITEL observations. The SED is well-fit by an intrinsic power-law spectral index of beta ~ 0.6 with a small amount (A_V = 0.10 +/- 0.05) of SMC-like host-galaxy extinction:
http://lyra.berkeley.edu/~dperley/080310/080310sed.png
Additional, late-time follow-up is planned.
GCN Circular #7409
P. Garnavich (Notre Dame), J. L. Prieto, R. Pogge (OSU) report:
We observed the position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) with the Large Binocular Telescope and LBC red and blue cameras on March 11 starting at 11:30 (UT) or 26.8 hours after the burst. On the red camera the images were taken through a Sloan-r filter and calibrating with the SDSS catalog (Cool et al.; GCN 7396) we find the brightness to be r=21.38+/-0.05 mag.
Extrapolating the decay from LBT observations of March 10 (Prieto et al., GCN 7392) with an index of 1.15, the afterglow is about 0.2 mag brighter than expected. This could be due to host galaxy light or deviations from a single power-law decay.
The LBT is an international collaboration among institutions in the United States, Italy and Germany. The LBT Corporation partners are:
```
*  The University of Arizona on behalf of the Arizona university system
*  Istituto Nazionale di Astrofisica, Italy
*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
*  The Ohio State University
*  The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
```
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GCN Circular #7410
M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We detected the optical afterglow of GRB 080310 (Cummings, et al., GCN 7382) in the error circle of the XRT position (Osborne et al. GCN 7394) with the 50cm MITSuME Telescope at Okayama Astrophysical Observatory on March 10 UT. Photometric calibration was done using USNO-B1.0 catalog. The light curve shows a plateau at around 19:00 - 20:00 UT (about 11 hours after the trigger). The photometric results are summarized below.
Observation date: 2008-03-10 UT
```
mid-UT     exp-T         g'            Rc            Ic
------------------------------------------------------------
15:09:46   60min     20.0+-0.2     19.7+-0.3     19.1+-0.2
16:24:47   60min     20.4+-0.2     20.2+-0.2     19.5+-0.2
17:39:46   60min     20.6+-0.1     20.4+-0.2     19.8+-0.2
18:54:44   60min     20.6+-0.2     20.5+-0.1     20.2+-0.3
19:57:05   42min     20.6+-0.2     20.3+-0.1     20.0+-0.2
------------------------------------------------------------
```
GCN Circular #7411
F. Yuan (U Mich), R. Quimby (Caltech), H. Swan (U Mich), C. Akerlof (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 080310 (Swift trigger 305288; Cummings et al., GCN 7382) and began imaging at UT 08:38:25.7 (5.7 sec after the GCN notice time) under cloudy conditions. The first usable image with a detection of the OT (Chornock et al. GCN 7381) starts at UT 09:03:03.4. Observations continued in fluctuating weather conditions until about 3 hours after the trigger.
The OT is slightly blended with the two nearby stars in ROTSE images. To reduce the contamination, we tried two different methods to obtain the OT magnitudes, first by subtracting the scaled PSF of the two nearby stars, and, second, by subtracting a reference image constructed from images taken on Mar. 11 between UT 05:26:28.5 and 06:00:53.6 (when the OT has dropped below our detection threshold). The two methods yield similar results. From 0.42 to 1.72 hour after the burst, the OT is observed to decay with a power-law index 0.6+/-0.1, consistent with the observation by the LBT (Garnavich et al., GCN 7390). The later images have degraded seeing and don't constrain the time dependence of the OT very well. The magnitudes reported below are unfiltered calibrated to SDSS r using standard stars in the pre-burst SDSS observations (Cool et al., GCN 7396).
```
Start_UT     End_UT      mag    magerror    mlim(of image)
---------------------------------------------------------------
09:03:03.4  09:07:31.2   17.2    0.1         18.4
09:56:17.5  10:09:49.8   18.0    0.1         19.4
```
GCN Circular #7412
Y. Urata, M. Im. I. Lee, K.Y. Huang, T.W. Chen, L.C. Huang on behalf of EAFON report:
"We have monitored the optical afterglow of GRB080310 (Cummings et al GCN 7382) on the night of March 10th using the Mt. Lemmon 1m and the Lulin 1m telescopes. These time coverage are 09:26 -- 12:54 UT (Mt. Lemmon) and 15:52--21:16 UT (Lulin), respectively. All of images taken with 300 sec exposure in V and R band show the afterglow clearly.
Based on our preliminary results calibrated using USNO-B1.0 catalog, we confirmed the decaying light curve with a power-law index 0.7+/0.1 between 0.8 and 2.1 hours after the burst. This result is consistent with the observations by the LBT (Garnavich et al., GCN 7390) and the ROTSE-III (Yuan et al., GCN 7411). The light curve between 7.3 and 12.2 hrs after the burst is well described by single power-law with index 0.8+/-0.1 in R-band. The extrapolation of this power-law is also consistent with the observation by the LBT (Garnavich et al. 7409). We could not confirm the plateau phase reported by the MITSuME (Yoshida et al., GCN 7410)."
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GCN Circular #7414
P. Garnavich (Notre Dame), J. L. Prieto, R. Pogge (OSU) report:
Beginning March 12.48 (UT), we again observed the position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) with the Large Binocular Telescope and LBC red and blue cameras. The seeing was 0.7 arcsec in the r-Sloan filter.
The brightness of the afterglow 2.12 days after the burst is measured to be r=21.67+/-0.05 mag, or only 0.3 mag fainter than the previous night. This corresponds to a power-law decay index of only 0.42 and confirms the slowing in the decay rate noted in GCN 7409.
It is unlikely that the slow fade is due to contamination from a host galaxy or a galaxy along the line of sight. To explain the observed decay rate, a galaxy would have to contribute at a magnitude near r=22.5, but nothing at this brightness is detected in the SDSS at the position of the afterglow. Also, the afterglow is consistent with a point source in the LBT images obtained in good seeing.
We conclude that the shallow decay rate is intrinsic to the afterglow and this suggests either a continuing energy input or that the shock has encountered a change in density of the ambient medium. (We must note another possibility: the afterglow is being gravitationally microlensed.)
```
The LBT is an international collaboration among institutions in the
United States, Italy and Germany. The LBT Corporation partners are:
*  The University of Arizona on behalf of the Arizona university system
*  Istituto Nazionale di Astrofisica, Italy
*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
*  The Ohio State University
*  The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
```
This message may be cited.
GCN Circular #7413
K. Kinugasa (Gunma Astronomical Observatory) report:
The position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) was observed with the 150 cm telescope of Gunma Astronomical Observatory. Starting at 15:09 and 18:01 UT (6.5 and 9.4 hours after the burst), Rc and Ic frames were acquired for sets of 5 x 3-min and 5 x 3-min exposures.
We clearly detected the optical counterpart in all frames. We estimated the R magnitute below and confirmed the fading trend. The decay index of single power-law is consistent with the result reported by Urata et al. (GCN 7412).
```
mid-UT     exp           Rc
-----------------------------------
15:18:50   5 x 3-min     20.1+-0.1
18:09:42   5 x 3-min     20.5+-0.1
-----------------------------------
```
GCN Circular #7415
Y. Urata, T.W. Chen, K.Y. Huang, L.C. Huang, M. Im, I. Lee on behalf of EAFON report:
"We have made R-band images for the optical afterglow of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) using the Lulin 1m telescope. According to USNO-B1.0 calibration, the afterglow at 1.44 days after the burst is R=21.3+/-0.1. This observation confirm the plateau or bump reported by Garnavich et al., (GCN 7414). The R-band lightcuve made from our observations (T.W. Chen et al., GCN 7395; Urata et al., GCN 7412) and the LBT points (Garnavich et al., GCN 7409, 7414) is resemble to that of GRB030329 (e.g. Lipkin et al 2004)."
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GCN Circular #7423
G. Wegner (Dartmouth), P. Garnavich (Notre Dame), J. L. Prieto, and K. Z. Stanek (OSU) report:
We observed the position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) with the Large Binocular Telescope (LBC red and blue cameras) on March 13.40 (UT) and with the MDM 2.4-m Hiltner telescope (Retrocam) on March 14.39 (UT) through Sloan-r filters.
Using stars calibrated by the SDSS, we estimate the following r-band magnitudes:
```
age (days)  r mag   error   telescope
3.04        22.45    0.05     LBT
4.03        23.10    0.10     MDM
```
The photometry indicates that the afterglow has resumed a steep decline. Including LBT photometry from March 12 (Garnavich et al., GCN 7414), we estimate a power-law decline index of 2.1 between 2 and 4 days after the burst.
A plot of the light curve is available at: http://www.nd.edu/~pgarnavi/LBT/grb080310/LBT_lightcurve.jpg
The LBT is an international collaboration among institutions in the United States, Italy and Germany. The LBT Corporation partners are:
```
*  The University of Arizona on behalf of the Arizona university system
*  Istituto Nazionale di Astrofisica, Italy
*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
   Society, the Astrophysical Institute Potsdam, and Heidelberg University
*  The Ohio State University
*  The Research Corporation, on behalf of The University of Notre Dame,
   University of Minnesota and University of Virginia
```
This message may be cited.
GCN Circular #7523
J. Hill (LBTO/UAz), R. Ragazzoni, A. Baruffolo (Padova), and P. Garnavich (Notre Dame) report:
The Large Binocular Telescope (LBT) observed the position of GRB 080310 (Chornock et al. GCN 7381; Cummings et al., GCN 7382) with the LBC red and blue cameras between March 19.3 and 19.5 (UT). Twenty 200 sec exposures in the Sloan-r filter were obtained in 1.3" seeing and with a significant sky background from the Moon.
The combined image shows a faint source present at the position of the afterglow. From stars calibrated in the SDSS we estimate the brightness of the source to be r=25.4+/-0.2 mag. This is consistent with an afterglow power-law decay index of 2.4 between 2 and 9 days after the burst (Wegner et al., GCN 7423). The true afterglow decay rate could be steeper if host galaxy light is contributing to the source flux.
A faint galaxy (r~24) is detected 2.1" southeast of the afterglow and another is 3.0" to the southwest. For a redshift of 2.43 and a standard cosmology, the projected distances from the afterglow are 17 kpc and 24 kpc. These galaxies may be the source of the two foreground absorption line systems observed in the afterglow spectrum (Vreeswijk et al., GCN 7391).
The LBT is an international collaboration among institutions in the United States, Italy and Germany. The LBT Corporation partners are:
```
*  The University of Arizona on behalf of the Arizona university system
*  Istituto Nazionale di Astrofisica, Italy
*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
   Society, the Astrophysical Institute Potsdam, and Heidelberg University
*  The Ohio State University
*  The Research Corporation, on behalf of The University of Notre Dame,
   University of Minnesota and University of Virginia
```
This message may be cited.
GCN Circular #7631
A. Henden (AAVSO) reports:
While the field of GRB080310 has been observed by SDSS, we have also obtained a four-night BVRcIc field calibration using the 35cm robotic telescope at Sonoita Research Observatory. The calibration file has a limiting magnitude around V=17, with good standards brighter than V=11 or so. The file is available at ftp://ftp.aavso.org/public/calib/grb/grb080310.dat
This calibration is based on numerous Landolt standards, and has an external zeropoint error of about 0.02mag. Our system is available for any other bright BVRI calibrations (4 The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network, and to John Gross of SRO for providing setup assistance for this field.
1201.1292 from 9 Jan 12
O. M. Littlejohns et al.: The origin of the early time optical emission of Swift GRB 080310
We present broadband multi-wavelength observations of GRB 080310 at redshift z = 2.43. This burst was bright and long-lived, and unusual in having extensive optical and near IR follow-up during the prompt phase. Using these data we attempt to simultaneously model the gamma-ray, X-ray, optical and IR emission using a series of prompt pulses and an afterglow component. Initial attempts to extrapolate the high energy model directly to lower energies for each pulse reveal that a spectral break is required between the optical regime and 0.3 keV to avoid over predicting the optical flux. We demonstrate that afterglow emission alone is insufficient to describe all morphology seen in the optical and IR data. Allowing the prompt component to dominate the early-time optical and IR and permitting each pulse to have an independent low energy spectral indices we produce an alternative scenario which better describes the optical light curve. This, however, does not describe the spectral shape of GRB 080310 at early times. The fit statistics for the prompt and afterglow dominated models are nearly identical making it difficult to favour either. However one enduring result is that both models require a low energy spectral index consistent with self absorption for at least some of the pulses identified in the high energy emission model.
1209.1506 from 10 Sep 12
P. M. Vreeswijk et al.: Time-dependent excitation and ionization modelling of absorption-line variability due to GRB 080310
We model the time-variable absorption of FeII, FeIII, SiII, CII and CrII detected in UVES spectra of GRB 080310, with the afterglow radiation exciting and ionizing the interstellar medium in the host galaxy at a redshift of z=2.42743. To estimate the rest-frame afterglow brightness as a function of time, we use a combination of the optical VRI photometry obtained by the RAPTOR-T telescope array -- which are presented in this paper -- and Swift's X-Ray Telescope observations. Excitation alone, which has been successfully applied for a handful of other GRBs, fails to describe the observed column-density evolution in the case of GRB 080310. Inclusion of ionization is required to explain the column-density decrease of all observed FeII levels (including the ground state 6D9/2) and increase of the FeIII 7S3 level. The large population of ions in this latter level (up to 10% of all FeIII) can only be explained through ionization of FeII, whereby a large fraction of the ionized FeII ions -- we calculate 31% using the Flexible Atomic (FAC) and Cowan codes -- initially populate the 7S3 level of FeIII rather than the ground state. This channel for producing a significant FeIII 7S3 level population may be relevant for other objects in which absorption lines from this level -- the UV34 triplet -- are observed, such as BAL quasars and Eta Carinae. This provides conclusive evidence for time-variable ionization in the circumburst medium, which to date has not been convincingly detected. However, the best-fit distance of the neutral absorbing cloud to the GRB is 200--400 pc, i.e. similar to GRB-absorber distance estimates for GRBs without any evidence for ionization. We find that the presence of time-varying ionization in GRB 080310 is likely due to a combination of the super-solar iron abundance ([Fe/H]=+0.2) and the low HI column density (log N(HI)=18.7). [abridged]

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Jochen Greiner, last update: 10-Sep-2012 [Disclaimer]