Gamma-ray Burst 070306

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:42:31 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     263361,   Seg_Num: 0
GRB_RA:          148.082d {+09h 52m 20s} (J2000),
                 148.178d {+09h 52m 43s} (current),
                 147.414d {+09h 49m 39s} (1950)
GRB_DEC:         +10.471d {+10d 28' 17"} (J2000),
                 +10.437d {+10d 26' 15"} (current),
                 +10.707d {+10d 42' 24"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       44847 [cnts]    Image_Peak=705 [image_cnts]
TRIGGER_DUR:     12.160 [sec] 
TRIGGER_INDEX:   478     E_range: 25-100 keV
BKG_INTEN:       217776 [cnts]
BKG_TIME:        59990.19 SOD {16:39:50.19} UT
BKG_DUR:         64 [sec]
GRB_DATE:        14165 TJD;    65 DOY;   07/03/06
GRB_TIME:        60088.17 SOD {16:41:28.17} UT
GRB_PHI:         106.31 [deg]
GRB_THETA:        33.01 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.30 [sigma]
IMAGE_SIGNIF:    9.85 [sigma]
MERIT_PARAMS:     +1  +0  +0  +4  +2  +0  +0  +0 +94  +1 
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 39"}
SUN_DIST:        160.89 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      193.11d {+12h 52m 25s}   -8.50d {-08d 29' 42"}
MOON_DIST:        48.56 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.67, 44.76 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      146.65, -2.30 [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 = 130.73,7.48 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:44:27 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     263361,   Seg_Num: 0
GRB_RA:          148.0980d {+09h 52m 23.5s} (J2000),
                 148.1938d {+09h 52m 46.5s} (current),
                 147.4297d {+09h 49m 43.1s} (1950)
GRB_DEC:         +10.4827d {+10d 28' 57.7"} (J2000),
                 +10.4488d {+10d 26' 55.5"} (current),
                 +10.7182d {+10d 43' 05.4"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60241.37 SOD {16:44:01.37} UT,   153.2 [sec] since BAT Trigger Time
CENTROID_X:      391.24,  raw= 391  [pixels]
CENTROID_Y:      300.99,  raw= 301  [pixels]
ROLL:            283.11 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   7.05
GRB_POS_XRT_Z:   209.66
IMAGE_URL:       sw00263361000msxps_rw.img
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 37"}
SUN_DIST:        160.90 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      193.12d {+12h 52m 29s}   -8.50d {-08d 30' 08"}
MOON_DIST:        48.56 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.66, 44.78 [deg] galactic lon,lat of the burst
ECL_COORDS:      146.66, -2.28 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:44:31 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     263361,   Seg_Num: 0
GRB_RA:          148.0980d {+09h 52m 23.5s} (J2000),
                 148.1938d {+09h 52m 46.5s} (current),
                 147.4297d {+09h 49m 43.1s} (1950)
GRB_DEC:         +10.4827d {+10d 28' 57.7"} (J2000),
                 +10.4488d {+10d 26' 55.5"} (current),
                 +10.7182d {+10d 43' 05.4"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60241.37 SOD {16:44:01.37} UT,   153.2 [sec] since BAT Trigger Time
CENTROID_X:      391.24,  raw= 391  [pixels]
CENTROID_Y:      300.99,  raw= 301  [pixels]
ROLL:            283.11 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   7.05
GRB_POS_XRT_Z:   209.66
IMAGE_URL:       sw00263361000msxps_rw.img
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 37"}
SUN_DIST:        160.90 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      193.12d {+12h 52m 29s}   -8.50d {-08d 30' 09"}
MOON_DIST:        48.56 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.66, 44.78 [deg] galactic lon,lat of the burst
ECL_COORDS:      146.66, -2.28 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:44:27 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     263361,   Seg_Num: 0
GRB_RA:          148.0980d {+09h 52m 23.5s} (J2000),
                 148.1938d {+09h 52m 46.5s} (current),
                 147.4297d {+09h 49m 43.1s} (1950)
GRB_DEC:         +10.4827d {+10d 28' 57.7"} (J2000),
                 +10.4488d {+10d 26' 55.5"} (current),
                 +10.7182d {+10d 43' 05.4"} (1950)
GRB_ERROR:       6.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.28e-08 [erg/cm2/sec]
GRB_SIGNIF:      4.89 [sigma]
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60241.37 SOD {16:44:01.37} UT,   153.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.21 261.27 243.48
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 37"}
SUN_DIST:        160.90 [deg]   Sun_angle= -10.8 [hr] (East of Sun)
MOON_POSTN:      193.12d {+12h 52m 29s}   -8.50d {-08d 30' 08"}
MOON_DIST:        48.56 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.66, 44.78 [deg] galactic lon,lat of the burst
ECL_COORDS:      146.66, -2.28 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:46:07 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.496d {+10d 29' 47"} (J2000)
POINT_ROLL:      283.112d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60250.16 SOD {16:44:10.16} UT,   162.0 [sec] since BAT Trigger\
 Time
FILTER:          10, White
BKG_MEAN:        1.860
N_STARS:         18
X_OFFSET:        128 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1087 [pixels]
Y_MAX:           1567 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00263361000msufc0161.fits
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 35"}
SUN_DIST:        160.85 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.13d {+12h 52m 32s}   -8.51d {-08d 30' 31"}
MOON_DIST:        48.63 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.29 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:46:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.496d {+10d 29' 47"} (J2000)
POINT_ROLL:      283.112d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60250.16 SOD {16:44:10.16} UT,   162.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.860
N_STARS:         18
X_OFFSET:        128 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1087 [pixels]
Y_MAX:           1567 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00263361000msufc0161.fits
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 35"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.14d {+12h 52m 32s}   -8.51d {-08d 30' 37"}
MOON_DIST:        48.64 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.29 [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:     Tue 06 Mar 07 16:47:23 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.496d {+10d 29' 47"} (J2000)
ROLL:            283.112d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60250.16 SOD {16:44:10.16} UT,   162.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     194892251
X_OFFSET:        420 [pixels]
Y_OFFSET:        1065 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       580
Y_GRB_POS:       1225
BINNING_INDEX:   1
IM_URL:          sw00263361000msuni0161.fits
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 34"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.14d {+12h 52m 34s}   -8.51d {-08d 30' 48"}
MOON_DIST:        48.64 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.29 [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:     Tue 06 Mar 07 16:47:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.496d {+10d 29' 47"} (J2000)
ROLL:            283.112d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60250.16 SOD {16:44:10.16} UT,   162.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     194892251
X_OFFSET:        420 [pixels]
Y_OFFSET:        1065 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       580
Y_GRB_POS:       1225
BINNING_INDEX:   1
IM_URL:          sw00263361000msuni0161.fits
SUN_POSTN:       346.86d {+23h 07m 27s}   -5.63d {-05d 37' 34"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.14d {+12h 52m 34s}   -8.51d {-08d 30' 52"}
MOON_DIST:        48.65 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.29 [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:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:52:51 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.498d {+10d 29' 52"} (J2000)
POINT_ROLL:      283.114d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60355.52 SOD {16:45:55.52} UT,   267.3 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.719
N_STARS:         16
X_OFFSET:        100 [pixels]
Y_OFFSET:        745 [pixels]
X_MAX:           1059 [pixels]
Y_MAX:           1704 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00263361000msufc0267.fits
SUN_POSTN:       346.87d {+23h 07m 28s}   -5.62d {-05d 37' 29"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.18d {+12h 52m 44s}   -8.53d {-08d 32' 03"}
MOON_DIST:        48.69 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.28 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Mar 07 16:53:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.498d {+10d 29' 52"} (J2000)
POINT_ROLL:      283.114d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60355.52 SOD {16:45:55.52} UT,   267.3 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.719
N_STARS:         16
X_OFFSET:        100 [pixels]
Y_OFFSET:        745 [pixels]
X_MAX:           1059 [pixels]
Y_MAX:           1704 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00263361000msufc0267.fits
SUN_POSTN:       346.87d {+23h 07m 28s}   -5.62d {-05d 37' 28"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.18d {+12h 52m 44s}   -8.54d {-08d 32' 07"}
MOON_DIST:        48.69 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.28 [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:     Tue 06 Mar 07 16:54:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.498d {+10d 29' 52"} (J2000)
ROLL:            283.114d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60355.52 SOD {16:45:55.52} UT,   267.3 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     194892357
X_OFFSET:        420 [pixels]
Y_OFFSET:        1065 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       580
Y_GRB_POS:       1225
BINNING_INDEX:   1
IM_URL:          sw00263361000msuni0267.fits
SUN_POSTN:       346.87d {+23h 07m 28s}   -5.62d {-05d 37' 27"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.19d {+12h 52m 46s}   -8.54d {-08d 32' 21"}
MOON_DIST:        48.70 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.28 [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:     Tue 06 Mar 07 16:54:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     263361,   Seg_Num: 0
POINT_RA:        148.041d {+09h 52m 10s} (J2000)
POINT_DEC:       +10.498d {+10d 29' 52"} (J2000)
ROLL:            283.114d
IMG_START_DATE:  14165 TJD;    65 DOY;   07/03/06
IMG_START_TIME:  60355.52 SOD {16:45:55.52} UT,   267.3 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     194892357
X_OFFSET:        420 [pixels]
Y_OFFSET:        1065 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       580
Y_GRB_POS:       1225
BINNING_INDEX:   1
IM_URL:          sw00263361000msuni0267.fits
SUN_POSTN:       346.87d {+23h 07m 28s}   -5.62d {-05d 37' 27"}
SUN_DIST:        160.84 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      193.19d {+12h 52m 46s}   -8.54d {-08d 32' 24"}
MOON_DIST:        48.70 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      225.61, 44.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      146.60, -2.28 [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:        All 4 attachments are included.

GCN Circular #6169
S. B. Pandey (UCL-MSSL), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), M. De Pasquale (UCL-MSSL), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), S. T. Holland (CRESST/GSFC/USRA), S. Immler (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), A. Moretti (INAF-OAB), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (NASA/ORAU), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU), E. Troja (INAF-IASFPA) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 16:41:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070306 (trigger=263361). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 148.082, +10.471 which is
```
   RA(J2000)  =  09h 52m 20s
   Dec(J2000) = +10d 28' 17"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). We did not receive a BAT lightcurve down TDRSS so we can not say anything about its shape. However, this 12 second trigger does have a strong image significance, and as such, the reliability is high.
The XRT began observing the field at 16:44:01 UT, 153 seconds after the BAT trigger. XRT found a bright, fading and uncatalogued X-ray source located at RA, Dec 148.0980, +10.4827 which is
```
   RA(J2000)  =  09h 52m 23.5s
   Dec(J2000) =  10d 28' 57.7"
```
with an uncertainty of 6.1 arcseconds (radius, 90% containment). This location is 71 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 0.1s image was 1.3e-08 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 162 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The 3-sigma upper limit is about 19.8 mag. The 8'x8' region for the list of sources generated on-board also covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03.
GCN Circular #6170
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 GRB070306 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/GRB070306
We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=148.082 (09:52:19.7), dec=10.4710 (10:28:15.6); Swift-BAT TRIGGER 263361), 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 GRB070306_sdss.calstar.dat, we report photometry and astrometry of 266 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 GRB070306_sdss.objects_flux.dat and GRB070306_sdss.objects_magnitudes.dat, we report photometry of 458 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 GRB070306_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB070306_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=0.148 mag, A_g=0.109 mag, A_r =0.079 mag, A_i=0.060 mag, and A_z=0.042 mag.
The file GRB070306_sdss.spectro.dat contains a list of the 4 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. (2006, ApJS, 162, 38), when using the data or referring to the technical documentation.
GCN Circular #6171
M. Uemura, A. Arai, and T. Uehara (Hiroshima Univ.), report on behalf of the KANATA GRB team:
We took optical and IR images of the field of GRB070306 (GCN 6169) at 16:57-17:18 UT 6 Mar. using TRISPEC attached to the KANATA 1.5-m telescope at Higashi-Hiroshima Observatory, Japan. The observation was performed with a bad seeing under strong wind. We obtained 10 sets of Rc, J, and Ks-band images with a 123, 120, and 96-s exposure time, respectively. The images were calibrated with neighbor stars in the USNO A2.0 and 2MASS catalog.
We cannot significantly detect the optical and IR afterglows at the XRT position reported in GCN 6169. The limit magnitudes are below:
```
UT                       Limit mag     Exp. Time
Mar. 6.71383             Rc > 20.3    123 * 10
Mar. 6.71378             J  > 17.3    120 * 10
Mar. 6.71363             Ks > 15.1     96 * 10
```
GCN Circular #6172
K.L. Page (U. Leicester) and S.B. Pandey (UCL-MSSL) report on behalf of the Swift-XRT team:
We have analysed the first three orbits of Swift-XRT data obtained for GRB 070306 (Pandey et al., GCN Circ. 6169), which includes 156 s of Windowed Timing (WT) data and 3.3 ks of Photon Counting (PC) mode data. Using the PC data we derive a refined position of RA, Dec = 148.0974, 10.4820, which is equivalent to
```
RA(J2000)  =  09 52 23.39
Dec(J2000) = +10 28 55.3
```
with an estimated error radius of 3.6 arcsec (90% confidence). This lies 67 arcsec and 3.3 arcsec from the onboard BAT and XRT positions given in GCN Circ. 6169, respectively.
The XRT light-curve initially decays between ~155 and 165 seconds after the trigger, followed by a small increase in count rate until 180 seconds; after this time, the curve shows a steep decay, with alpha_1 = 6.3 +/- 0.2 until 411 +/- 17 seconds post-trigger, at which point the decay flattens to alpha_2 = 0.22 +/- 0.08. All error bars are at the 90% confidence level. Note that Swift triggered on a precursor; if T0 for the light-curve fits were to be referenced to the main peak of the burst, around 100 seconds later, this initial decay would not be so steep.
The WT spectrum can be modelled by a power-law of Gamma = 2.29 +/- 0.05, with a total absorbing column of 3.9x10^21 cm^-2, compared to the Galactic column of 2.94x10^20 cm^-2 in this direction. This value of NH was calculated from the later PC data (Gamma = 2.14 +/- 0.17), when the spectral evolution apparent during the initial steep decay has ceased. The mean observed (unabsorbed) flux over 0.3-10 keV for this WT spectrum is 1.73e-9 (3.48e-9) erg cm^-2 s^-1.
If the decay continues with a slope of alpha = 0.22, the count rate is predicted to be 0.21 count s^-1 at 24 hours. This corresponds to an observed flux of 1.0e-11 erg cm^-2 s^-1 (over 0.3-10 keV), with the unabsorbed value being 1.9e-11 erg cm^-2 s^-1, using the spectral fit to the PC data.
This circular is an official product of the XRT team.
GCN Circular #6173
S. D. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), S. B. Pandey (UCL-MSSL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070306 (trigger #263361) (Pandy, et al., GCN Circ. 6169). The BAT ground-calculated position is RA, Dec = 148.097, +10.477 deg which is
```
   RA(J2000)  = 09h 52m 23.3s 
   Dec(J2000) = 10d 28' 37.2" 
```
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 28%.
The mask-weighted lightcurve shows a small precursor peak starting at T-120 through T-105 sec. Then a second pulse (of equal amplitude) starting at ~T-15 sec and exponentially decaying back to background at ~T+50 sec. Then a much larger peak starting at ~T+75 sec, exponentially rising to a peak at T+98 sec, end then exponentially decaying to background at ~T+220 sec. T90 (15-350 keV) is 210 +- 10 sec (estimated error including systematics).
The time-averaged spectrum from T-118.8 to T+186.5 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.10. The fluence in the 15-150 keV band is 5.5 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+98.27 sec in the 15-150 keV band is 4.2 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6174
E. Rol (Leicester), A. Levan (Warwick), N. Tanvir (Leicester), M. Schirmer (ING), A.J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report:
"We observed the location of GRB 070306 (Pandey et al. GCNC 6169) using the 4.2m WHT (+LIRIS) in the JHK bands beginning at 19:57 UT, roughly 3.27 hours after the burst. Within the X-ray localisation of Page et al. (GCNC 6172) we find a single source, which is also present in the SDSS pre-observations of the field (Cool et al. GCNC 6170). The location of this source is
```
RA:  09:52:23.31 (J2000)
DEC: +10:28:55.26 (J2000)
```
with errors of 0.3" in each coordinate.
Preliminary photometry implies K=17.9 +/- 0.1. Compared to the measured SDSS magnitudes this implies r-K~5. This is unusually red for a GRB host galaxy and may indicate a contribution from the IR afterglow. Further observations will be necessary to ascertain any variability."
GCN Circular #6175
The error region of GRB 070306 (Pandey et al. GCN 6169; Page et al. GCN 6172; Barthelmy et al. 6173) was observed with the ART-3a and ART-3b under the partly cloudy condition.
The imaging started at 2007 March 6, 16:43:00 UT (92 s after the trigger) in Ic band (ART-3a), and at 16:43:24 UT (116 s after the trigger) in J band (ART-3b). We do not detect neither optical nor near infrared counterpart for the IR afterglow candidate (Rol et al. GCN 6174). From the useful data sets, we derive the following 3 sigma upper limits for any new source within the XRT error region (GCN 6172), relative to USNO-B1.0 I2 or 2MASS J magnitudes.
```
-----------------------------------------
StartUT         Filter  Limit   Exposure
=========================================
16:52:28        Ic      17.3    60s x 7
16:48:28        J       13.3    20s x 121
=========================================
```
GCN Circular #6176
A. Levan (Warwick), E. Rol (Leicester), N. Tanvir (Leicester), M. Schirmer (ING) and A.J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report:
We have re-observed the location of GRB 070306 (Pandey et al., GCNC 6169) with WHT+LIRIS, in K-band. Observations started at 00:39 UT, 7.97 hours after the trigger. Comparison with our previous K-band observation (Rol et al., GCNC 6174) shows the suggested candidate afterglow to have increased in brightness by about a magnitude, confirming it to be variable and the near infrared afterglow of GRB 070306. Further observations are strongly encouraged.
GCN Circular #6177
M. De Pasquale, S.B. Pandey (MSSL/UCL) report on the behalf of the Swift UVOT team:
Swift/UVOT observed the field of GRB070306 (Pandey et al. 2007, GCN 6169) starting 146s after the trigger with the settling expsoure.
UVOT did not find any source inside the refined XRT error circle (Page et al. 2007, GCN 6172), down to the following 3 sigma upper limits in the White filter finding exposure and in the coadded frames in all filters:
Filter t_start(s) t_stop(s) Exp(s) Mag 3-sig UL
```
Wh_find      162      262       98         19.8

V            267    11158     1259         20.5
B            745     6257      403         21.5
U            721     6053      413         21.0
W1           697     5848      236         19.0
M2           673     5633      236         18.7
W2           773     6651      397         19.5
Wh           162     6462      512         20.7
```
These upper limits are not corrected for the small Galactic extinction, corresponding to a reddening of E(B-V)=0.03 (Schlegel et al. 1998), towards the direction of this burst.
GCN Circular #6178
D. Malesani (DARK/NBI), A.O. Jaunsen (Univ. Oslo), C.C. Thoene, J. Hjorth (DARK/NBI), D. Paraficz (NOT), E. Leitet, and B. Caldwell (Univ. Uppsala), report on behalf of a larger collaboration:
We observed the field of GRB 070306 (Pandey et al., GCN 6169) with the NOT equipped with StanCam. Imaging was carried out in the I filter, starting on Mar 6.946 UT (6 hr after the GRB), with a seeing of 1". The object visible in the SDSS (SDSS J095223.31+102855.4) and reported by Rol et al. (GCN 6174) and Levan et al. (GCN 6176) is seen in our images.
Preliminary photometry calibrated against the SDSS i-band magnitudes (Cool et al., GCN 6170) provides i(AB) = 22.65+-0.30 (mean time Mar 6.954 UT). This is consistent, within the large errors, with the value measured in the SDSS for this object: i(AB) = 22.8+-0.4, and indicates little contribution from the afterglow in the I band at the epoch of our observation.
Comparison with the magnitudes reported by Rol et al. (GCN 6174) further suggests that either the host galaxy, or the afterglow, or both, are quite red.
Using the X-ray flux at 6 hr from Nat Butler's web page (http://astro.berkeley.edu/~nat/swift/00263361/bat_xrt.jpg; see also Page et al., GCN 6172), we can measure a limit on the broad-band spectral index beta_OX < 0.2 at 6 hr after the GRB. According to the criterion by Jakobsson et al. (2004, ApJ, 617, L21), this burst is classified as dark. The detection of the relatively bright host in the SDSS g filter and the presence of a large absorbing column in the X-ray spectrum (Page et al., GCN 6172; Grupe et al. 2007, AJ, in press; astro-ph/0612104) imply the redshift is not very large. Therefore this afterglow was likely suffering significant dust extinction.
GCN Report 38.1
GCN_Report 38.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_38_1.pdf by S.B. Pandey at MSSL-UCL titled: "Swift Observations on GRB 070306"
GCN Circular #6180
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB 070306 (GCN 6169) at a frequency of 8.46 GHz on 2007 March 8th at 5.22 UT. The GRB is undetected and the 2-sigma upper limit on the peak radio flux at the SWIFT-XRT position (GCN 6172) is 60 uJy (rms 30 uJy).
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #6184
S.Maeno, E.Sonoda, R.Hara, H.Tanaka, K.Tanaka, T.Matsumura, M.Yamauchi (University of Miyazaki)
We have observed the field covering the error region of GRB 070306 (GCN 6169) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started from 16:43:36 UT on Mar. 6 (128 s after the trigger).
We have compared our data of 30 sec exposures with the USNO-A2.0 catalog. There is no new source at the XRT position(GCN 6172).
The upper limit is as follows:
```
--------------------------------------------------------------
Start(UT)	End(UT)	    Num. of frames	Limit (mag.)	
--------------------------------------------------------------
16:43:36	16:44:06	1		~15.8
16:45:24        16:59:40        9               ~17.0
---------------------------------------------------------------
```
GCN Circular #6202
A.O. Jaunsen (Univ. Oslo), C.C. Thoene, J.P.U. Fynbo, J. Hjorth (DARK/ NBI), P. Vreeswijk (ESO) report on behalf of a larger collaboration.
We observed the field of GRB 070306 (Pandey et al., GCN 6169 & GCN Report 38.1) with the ESO/VLT equipped with FORS2. Observations started on 2007 Mar 08.11 UT (about 34 hr after the GRB) and three 1800-s spectra were acquired with the 300V grism covering a wavelength range of 3500-9500A.
The spectrum consists of a largely featureless continuum from about 4000-9400A with the exception of an apparent emission line at ~9310A. The emission-line is very close to the prominent telluric skyline at 9313A, but is seen in each of the three individual spectra. The lack of other detected lines in the observed wavelength range suggests that the emission line is due to [O II] at a red-shift of z=1.497. It should be cautioned, however, that this host galaxy appears to be highly reddened (as already noted by Rol et al., GCN 6174), which could have an unforeseen suppression-effect on the bluer part of the spectrum.
We acknowledge the excellent support from the ESO/Paranal staff.
GCN Report 38.2
GCN_Report 38.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_38_2.pdf by S.B. Pandey at MSSL-UCL titled: "Final Swift Observations of GRB 070306"
0803.4017from 28 Mar 2008
Jaunsen: GRB 070306: A Highly Extinguished Afterglow
Abstract: We report on the highly extinguished afterglow of GRB 070306 and the properties of the host galaxy. An optical afterglow was not detected at the location of the burst, but in near-infrared a doubling in brightness during the first night and later power-law decay in the K band provided a clear detection of the afterglow. The host galaxy is relatively bright, R ~ 22.8. An optical low resolution spectrum revealed a largely featureless host galaxy continuum with a single emission line. Higher resolution follow-up spectroscopy shows this emission to be resolved and consisting of two peaks separated by 7 AA, suggesting it to be [O II] at a redshift of z = 1.49594 +- 0.00006. The infrared color H-K = 2 directly reveals significant reddening. By modeling the optical/X-ray spectral energy distribution at t = 1.38 days with an extinguished synchrotron spectrum, we derive A_V = 5.5 +- 0.6 mag. This is among the largest values ever measured for a GRB afterglow and visual extinctions exceeding unity are rare. The importance of early NIR observations is obvious and may soon provide a clearer view into the once elusive 'dark bursts'.

Back to JG's homepage

Jochen Greiner, last update: 31-Mar-2008 [Disclaimer]