Gamma-ray Burst 060502

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE


TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:20:13 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     208169,   Seg_Num: 0
GRB_RA:          240.858d {+16h 03m 26s} (J2000),
                 240.868d {+16h 03m 28s} (current),
                 240.781d {+16h 03m 07s} (1950)
GRB_DEC:         +66.595d {+66d 35' 42"} (J2000),
                 +66.578d {+66d 34' 40"} (current),
                 +66.731d {+66d 43' 50"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5709 [cnts]    Image_Peak=332 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       32363 [cnts]
BKG_TIME:        10998.83 SOD {03:03:18.83} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13857 TJD;   122 DOY;   06/05/02
GRB_TIME:        11012.14 SOD {03:03:32.14} UT
GRB_PHI:         -131.83 [deg]
GRB_THETA:        34.90 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     24.55 [sigma]
IMAGE_SIGNIF:    12.69 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +8  +0  +0 +11  +1 
SUN_POSTN:        39.16d {+02h 36m 39s}  +15.31d {+15d 18' 43"}
SUN_DIST:         96.54 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.54d {+06h 30m 10s}  +28.45d {+28d 27' 06"}
MOON_DIST:        80.98 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      166.42, 78.52 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 30 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 13.15,8.74 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:21:02 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     208169,   Seg_Num: 0
GRB_RA:          240.9262d {+16h 03m 42.2s} (J2000),
                 240.9362d {+16h 03m 44.6s} (current),
                 240.8495d {+16h 03m 23.8s} (1950)
GRB_DEC:         +66.5980d {+66d 35' 52.7"} (J2000),
                 +66.5809d {+66d 34' 51.1"} (current),
                 +66.7335d {+66d 44' 00.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       74 [cnts]
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11088.43 SOD {03:04:48.43} UT,   76.3 [sec] since BAT Trigger Time
CENTROID_X:      289.62,  raw= 290  [pixels]
CENTROID_Y:      263.00,  raw= 263  [pixels]
ROLL:            21.04 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -84.37
GRB_POS_XRT_Z:   -27.51
IMAGE_URL:       sw00208169000msxps_rw.img
SUN_POSTN:        39.16d {+02h 36m 39s}  +15.31d {+15d 18' 44"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.5 [hr] (West of Sun)
MOON_POSTN:       97.55d {+06h 30m 12s}  +28.45d {+28d 27' 04"}
MOON_DIST:        80.99 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.92, 40.90 [deg] galactic lon,lat of the burst
ECL_COORDS:      166.43, 78.55 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:23:46 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.864d {+16h 03m 27s} (J2000)
POINT_DEC:       +66.600d {+66d 35' 59"} (J2000)
POINT_ROLL:      21.038d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11096.79 SOD {03:04:56.79} UT,   84.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.033
N_STARS:         86
X_OFFSET:        448 [pixels]
Y_OFFSET:        552 [pixels]
X_MAX:           1407 [pixels]
Y_MAX:           1511 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00208169000msufc0084.fits
SUN_POSTN:        39.17d {+02h 36m 40s}  +15.31d {+15d 18' 46"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.58d {+06h 30m 19s}  +28.45d {+28d 26' 59"}
MOON_DIST:        80.97 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.40, 78.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:24:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.864d {+16h 03m 27s} (J2000)
POINT_DEC:       +66.600d {+66d 35' 59"} (J2000)
ROLL:            21.038d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11096.79 SOD {03:04:56.79} UT,   84.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     168231897
X_OFFSET:        932 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1092
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00208169000msuni0084.fits
SUN_POSTN:        39.17d {+02h 36m 40s}  +15.31d {+15d 18' 46"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.58d {+06h 30m 20s}  +28.45d {+28d 26' 58"}
MOON_DIST:        80.97 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.40, 78.52 [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 02 May 06 03:24:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     208169,   Seg_Num: 0
GRB_RA:          240.858d {+16h 03m 26s} (J2000),
                 240.868d {+16h 03m 28s} (current),
                 240.781d {+16h 03m 07s} (1950)
GRB_DEC:         +66.595d {+66d 35' 42"} (J2000),
                 +66.578d {+66d 34' 40"} (current),
                 +66.731d {+66d 43' 50"} (1950)
GRB_DATE:        13857 TJD;   122 DOY;   06/05/02
GRB_TIME:        11012.14 SOD {03:03:32.14} UT
TRIGGER_INDEX:   148
GRB_PHI:         -131.83 [deg]
GRB_THETA:        34.90 [deg]
DELTA_TIME:      -51.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     24.55 [sigma]
IMAGE_SIGNIF:    12.69 [sigma]
LC_URL:          sw00208169000msb.lc
SUN_POSTN:        39.17d {+02h 36m 40s}  +15.31d {+15d 18' 47"}
SUN_DIST:         96.54 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.59d {+06h 30m 21s}  +28.45d {+28d 26' 58"}
MOON_DIST:        80.97 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      166.42, 78.52 [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 = 13.15,8.74 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:26:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.864d {+16h 03m 27s} (J2000)
POINT_DEC:       +66.600d {+66d 35' 59"} (J2000)
POINT_ROLL:      21.038d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11096.79 SOD {03:04:56.79} UT,   84.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.033
N_STARS:         86
X_OFFSET:        448 [pixels]
Y_OFFSET:        552 [pixels]
X_MAX:           1407 [pixels]
Y_MAX:           1511 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00208169000msufc0084.fits
SUN_POSTN:        39.17d {+02h 36m 40s}  +15.31d {+15d 18' 48"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.60d {+06h 30m 25s}  +28.45d {+28d 26' 55"}
MOON_DIST:        80.96 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.40, 78.52 [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 02 May 06 03:27:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.864d {+16h 03m 27s} (J2000)
POINT_DEC:       +66.600d {+66d 35' 59"} (J2000)
ROLL:            21.038d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11096.79 SOD {03:04:56.79} UT,   84.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     168231897
X_OFFSET:        932 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1092
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00208169000msuni0084.fits
SUN_POSTN:        39.17d {+02h 36m 40s}  +15.31d {+15d 18' 49"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.62d {+06h 30m 28s}  +28.45d {+28d 26' 52"}
MOON_DIST:        80.96 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.40, 78.52 [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_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:29:04 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.866d {+16h 03m 28s} (J2000)
POINT_DEC:       +66.597d {+66d 35' 51"} (J2000)
POINT_ROLL:      21.040d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11202.11 SOD {03:06:42.11} UT,   190.0 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        0.903
N_STARS:         126
X_OFFSET:        612 [pixels]
Y_OFFSET:        662 [pixels]
X_MAX:           1571 [pixels]
Y_MAX:           1621 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00208169000msufc0189.fits
SUN_POSTN:        39.17d {+02h 36m 41s}  +15.31d {+15d 18' 50"}
SUN_DIST:         96.54 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.63d {+06h 30m 31s}  +28.45d {+28d 26' 50"}
MOON_DIST:        80.96 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.41, 78.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:30:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     208169,   Seg_Num: 0
POINT_RA:        240.866d {+16h 03m 28s} (J2000)
POINT_DEC:       +66.597d {+66d 35' 51"} (J2000)
POINT_ROLL:      21.040d
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11202.11 SOD {03:06:42.11} UT,   190.0 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        0.903
N_STARS:         126
X_OFFSET:        612 [pixels]
Y_OFFSET:        662 [pixels]
X_MAX:           1571 [pixels]
Y_MAX:           1621 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00208169000msufc0189.fits
SUN_POSTN:        39.17d {+02h 36m 41s}  +15.31d {+15d 18' 51"}
SUN_DIST:         96.54 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:       97.65d {+06h 30m 35s}  +28.45d {+28d 26' 47"}
MOON_DIST:        80.96 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.94, 40.92 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      166.41, 78.52 [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 02 May 06 03:20:59 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     208169,   Seg_Num: 0
GRB_RA:          240.9262d {+16h 03m 42.2s} (J2000),
                 240.9362d {+16h 03m 44.6s} (current),
                 240.8495d {+16h 03m 23.8s} (1950)
GRB_DEC:         +66.5980d {+66d 35' 52.7"} (J2000),
                 +66.5809d {+66d 34' 51.1"} (current),
                 +66.7335d {+66d 44' 00.4"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.30e-09 [erg/cm2/sec]
GRB_SIGNIF:      8.60 [sigma]
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11088.43 SOD {03:04:48.43} UT,   76.3 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.22 261.18 243.32
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        39.16d {+02h 36m 39s}  +15.31d {+15d 18' 44"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.5 [hr] (West of Sun)
MOON_POSTN:       97.55d {+06h 30m 12s}  +28.45d {+28d 27' 04"}
MOON_DIST:        80.99 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.92, 40.90 [deg] galactic lon,lat of the burst
ECL_COORDS:      166.43, 78.55 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 May 06 03:21:31 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     208169,   Seg_Num: 0
GRB_RA:          240.9262d {+16h 03m 42.2s} (J2000),
                 240.9362d {+16h 03m 44.6s} (current),
                 240.8495d {+16h 03m 23.8s} (1950)
GRB_DEC:         +66.5980d {+66d 35' 52.7"} (J2000),
                 +66.5809d {+66d 34' 51.1"} (current),
                 +66.7335d {+66d 44' 00.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       74 [cnts]
IMG_START_DATE:  13857 TJD;   122 DOY;   06/05/02
IMG_START_TIME:  11088.43 SOD {03:04:48.43} UT,   76.3 [sec] since BAT Trigger Time
CENTROID_X:      289.62,  raw= 290  [pixels]
CENTROID_Y:      263.00,  raw= 263  [pixels]
ROLL:            21.04 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -84.37
GRB_POS_XRT_Z:   -27.51
IMAGE_URL:       sw00208169000msxps_rw.img
SUN_POSTN:        39.16d {+02h 36m 39s}  +15.31d {+15d 18' 44"}
SUN_DIST:         96.53 [deg]   Sun_angle= 10.5 [hr] (West of Sun)
MOON_POSTN:       97.55d {+06h 30m 13s}  +28.45d {+28d 27' 03"}
MOON_DIST:        80.99 [deg]
MOON_ILLUM:      21 [%]
GAL_COORDS:       99.92, 40.90 [deg] galactic lon,lat of the burst
ECL_COORDS:      166.43, 78.55 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN Circular #5047
V. La Parola (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), E. Troja (INAF-IASFPA) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 03:03:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060502 (trigger=208169). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 240.858, +66.595 {16h 03m 26s, +66d 35' 42"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a roughly triangular shaped single peak starting at ~T-8 sec and lasting until ~T+20 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 03:04:48 UT, 76 seconds after the BAT trigger. Ground analysis of the initial XRT data found a bright, uncatalogued, fading X-ray source located at RA(J2000) = 16h 03m 42.9s, Dec(J2000) = +66d 35' 57.4", with an estimated uncertainty of 3.9 arcseconds (90% confidence radius). This location is 98 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 1.3e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 85 seconds after the BAT trigger. There is an 18.4 magnitude source that is not visible in the Digitized Sky Survey images, at J2000 coordinate 16h 03m 42.48s, +66d 36' 02.5" (240.9270, +66.6007). The position is 5.7 arcseconds from the center of the XRT error circle.
This burst triggered BAT at the beginning of a Malindi telemetry downlink session and so the downlink of the TDRSS notices was delayed until the end of the pass (~18 min).
GCN Circular #5048
S. B. Cenko, E. O. Ofek (Caltech), and D. B. Fox (Penn State) report on behalf of a larger collaboration:
We have imaged the field of GRB060502 (La Parola et al., GCN 5047) with the automated Palomar 60-inch telescope. Observations began immediately following astronomical twilight. The UVOT optical candidate is detected in individual 60 s R, g, and i' images and is cleary fading. We therefore confirm this object as the afterglow of GRB060502.
We estimate the magnitude of the afterglow to be R ~ 19.8 approximately 40 minutes after the burst trigger (calculated with reference to several nearby USNO-B objects).
Observations are continuing.
GCN Circular #5049
G. G. Williams (MMTO), and P. A. Milne (Steward Observatory) on behalf of the Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box of GRB060502 (Swift Trigger 208169, GCNC 5047) at 03:20:46 UT, 1034 seconds after the burst (17.23 min; 33 seconds after the delayed GCN notice). Our initial observations include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures, all in the R-band.
Under thin cirrus we do not detect the Swift afterglow reported by La Parola et al. and Cenko et al. (GCN 5047 & 5048) in our earliest 60 second exposure to the following 3-sigma limiting magnitude estimated using nearby USNO-B1.0 stars:
```
t_mid obs (UT)	exp t (s)	t-t_0 (s)	Limit
--------------------------------------------------------
03:24:56	60 		1284 		R > 17.9
```
Additional observations and analysis, including image stacking, are ongoing.
GCN Circular #5051
H.-W. Chen (U Chicago), R. McMillan (APO), A. Bender (U Colorado), D. York, and D. Lamb (U Chicago) report on behalf of a larger collaboration:
"We observed the afterglow of GRB060502A reported by La Parola et al. (GCN 5047) and confirmed by Cenko et al. (GCN5048), using the Dual Imaging Spectrograph (DIS) with a 1.5-arcsec slit on the 3.5 m telescope at the Apache Point Observatory. The observations started at UT 05:52:33 on May 2, 2006, ~ 2.8 hours after the inital Swift/BAT trigger, and were carried out under a mean seeing condition of 1.3 arcsec in a sequence of two 1800-sec exposures. The final stacked spectrum covers the spectral range from 3800 Ang to 8500 Ang with a spectral resolution of 2.4 Ang per pixel, and appears to be featureless. The abundant fluxes observed below 4000 Ang and the lack of spectral discontinuity below 4500 Ang indicate that the GRB originated at redshift z < 2.2. We determine a tentative redshift for the GRB afterglow at z=0.099 +/0.001 based on the tentative identifications of CaII H&K absorption features at around 4322 and 4361 Ang.
Further analysis is underway.
This message may be cited."
GCN Circular #5052
A. Cucchiara (Penn State), P.A. Price (IfA, Hawaii), D.B. Fox, (Penn State), S.B. Cenko (SRL, Caltech) and B.P. Schmidt (RSAA, ANU) report on behalf of a larger collaboration:
We have observed the optical afterglow of GRB 060502 (La Parola et al., GCN 5047, Cenko et al., 5048) with the GMOS instrument on Gemini North telescope. Observations consisted of 2 x 1800 sec exposures with the R400 grating, commencing at 2006 May 2.34 UTC. In the summed spectrum, we identify an absorption system consisting of Fe II, Mg II and Mg I at a redshift of z ~ 1.51. No other absorption or emission line systems are apparent.
We acknowledge the rapid response effort of Gemini personnel that yielded these data.
GCN Circular #5053
A. Parsons (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (UMD), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), on behalf of the Swift-BAT team:
Using the data set from T-119 to T+229 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060502 (trigger #208169) (La Parola, et al., GCN 5047). The BAT ground-calculated position is (RA,Dec) = 240.941, 66.600 deg {16h 3m 45.8s, 66d 35' 59.5"} (J2000) +- 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%.
The mask-weighted lightcurve shows a main peak starting at T-5 sec and ending at T+30 sec. The second weak peak follows in a duration of ~15 sec. T90 (15-350 keV) is 33 +- 5 sec (estimated error including systematics).
The time-averaged spectrum from T-5.8 to T+42.0 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.43 +- 0.08. The fluence in the 15-150 keV band is 2.2 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band is 1.7 +- 0.2 ph/cm2/sec.
Eiso is 5.8e+49 ergs (16.5 - 164.9 keV in the GRB rest frame) and 1.5e+52 ergs (37.7 - 376.5 keV in the GRB rest frame) using z = 0.099 (Chen et al. GCN 5051) and z = 1.51 (Cucchiara et al. GCN 5052) respectively.
All the quoted errors are at the 90% confidence level.
GCN Circular #5054
V. La Parola, E. Troja, V. Mangano (INAF-IASFPA), S.=20 Campana (INAF-OAB), K. L. Page (U Leicester), J. Kennea,=20 D.N. Burrows (PSU), on behalf of the Swift-XRT team.
We have analyzed the first two orbit of data of GRB060502 (La Parola et al 2006, GCN 5047). The XRT data set consists of 71 s exposure in Windowed Timing (WT) mode followed by 355 s exposure in Photon Counting (PC) mode in the first orbit and 2.4 ks in the=20 second orbit.
The refined position of the source is
```
     RA  (2000) = 16h 03m 42.9s
     Dec (2000) = 66 35' 58.1"
```
with an uncertainty of 3.7 arcsec (90% confinement). This position is only 1 arcsec from the one calculated=20 from early downlinked data (La Parola et al 2006, GCN 5047),=20 5.1 arcsec from the UVOT afterglow position and 17.6" from=20 the BAT refined position (Parsons et al. GCN5053).
The 0.2-10 keV X-ray light curve shows an initial fast decay with slope -2.87 +/- 0.11 and a break at 252=20 +/- 17 s from the trigger followed by a second decay slope of -0.54 +/- 0.05.
The WT spectrum (collected during the pre-break phase) can be fitted with a power law (photon index 2.3 +/-0.5) plus a soft thermal component (which can be modelled with=20 a blackbody at 0.13+/-0.02 keV), with intrinsic absorption=20 (0.45+/-0.15)e22 cm-2, assuming a redshift of 1.51=20 (Cucchiara et al. GCN5052).
The PC spectrum after the break is fitted with an absorbed=20 power law with photon index 1.99 +/-0.15 and intrinsic absorption=20 (0.6+/-0.2)e22 cm-2. The Galactic absorption is 2.97e20 cm-2.
With the present decay slope, the 0.2-10 keV flux at 24h=20 after the trigger is expected to be ~2e-12 erg/s/cm-2
This Circular is an official product of the Swift XRT=20 Team.
GCN Circular #5060
M. Nysewander, J. Harvey, A. Foster, D. Reichart, J. A. Crain, K. Ivarsen report on behalf of the UNC team of the FUN GRB Collaboration:
Under the automated control of SkyNet, the 0.37-m TTT telescope, located outside of Fort Collins, Colorado, began observing the localization of GRB 060502A (Parola et al., GCN 5047) 65 seconds after the initial notification, and 17.8 minutes after the time of the burst in the V & Red filters.
In our first 160-s exposure at a mean time of 19.1 minutes after the burst, we do not see the afterglow (Parola et al. GCN 5047, Cenko et al., 5048) down to a 3-sigma limiting magnitude of R ~ 17.5.
GCN Circular #5068
T. S. Poole (UCL-MSSL), and V. La Parola (INAF-IASFPA) on behalf of the Swift/UVOT team.
The Swift/UVOT began observing the field of GRB060502 (BAT Trigger=208169, V. La Parola, et. al, GCN 5047) at 03:04:56 UT, 84s after the BAT trigger.
We detect a fading source with a calculated position of RA = 16:03:42.48 and Dec = +66:36:02.5 (J2000) in the V, B and White filters, and the summed UVW1 filter. The error in the coordinates of the UVOT source is +/- 0.56 arcsec (90% confidence). The position is 4.4 arcseconds from the centre of the XRT error circle reported by V. La Parola, et. al, (GCN 5054). Checks against the Digitized Sky Survey images yield no known source at this position on the sky.
The calculated magnitudes of the first afterglow observations in the UVOT filters are given below. The limiting magnitudes are given to a 3 sigma limit. These values are not corrected for Galactic extinction; E(B-V) = 0.033.
```
Filter   T_range(s)  T_exp(s)  Magnitude	Comments

V	 190-536     346       18.70 +/- 0.14	- source detection
V	 5092-5292   200       20.19		- 3 sigma upper limit
B	 4478-4678   200       20.04 +/- 0.16	- source detection
B	 5910-6110   200       20.91 +/- 0.34	- source detection
U	 4273-4473   200       20.84		- 3 sigma upper limit
U	 5706-5905   200       20.78		- 3 sigma upper limit
UVW1	 4069-4269   200       20.63		- 3 sigma upper limit
UVW1	 5501-5701   200       20.61		- 3 sigma upper limit
UVW1	 4069-5701   400       20.89 +/- 0.40	- source detection
UVM2	 3864-4064   200       20.85		- 3 sigma upper limit
UVM2	 5296-5496   200       21.03		- 3 sigma upper limit
UVW2	 4888-5087   200       21.60		- 3 sigma upper limit
WHITE	 84-184	     100       18.50 +/- 0.07	- source detection
WHITE	 4682-4882   200       20.53 +/- 0.20	- source detection
WHITE	 6115-6314   200       21.22		- 3 sigma upper limit
```
Where T_range is time post-trigger, and T_exp is the exposure time of the observation. A 6 arcsec radius was used for all filters.
When summing the two UVW1 200s exposures we see a source detection above 3 sigma. This give a z upper limit of 1.9.
This message may be cited.
GCN Circular #5070
M. Hicken (CfA) and P. Garnavich (Notre Dame)
Images of the field around GRB 060502A (La Parola et al., GCN 5047) were obtained with the FLWO 1.2m telescope and KepCAM beginning on 2006 May 2.23 (UT). Four R-band exposures of 120 and 180 seconds were combined and the optical afterglow (Cenko et al., GCN 5048) is detected but is faint. The mean time of the combined exposures is 2.77 hours after the burst. Using stars in the USNO-A2.0 for calibration, we estimate the brightness of the afterglow to be R=20.1 +/- 0.3 mag.
Also using the USNO-A2.0 catalog we estimate the position of the afterglow to be RA=16:03:42.63 DEC=66:36:03.7 (J2000) with an error of 0.7" which is consistent with the Swift/UVOT position (Poole et al., GCN 5068).
GCN Circular #5195
Pall Jakobsson (Univ. of Hertfordshire), Erik Zackrisson, Janne Holopainen (Tuorla Observatory), Genoveva Micheva (Stockholm Observatory), Brian L. Jensen, Johan P. U. Fynbo and Jens Hjorth (DARK, NBI) report:
Using MOSCA on the 2.56-meter Nordic Optical Telescope, we obtained 3*300 s R-band images of the GRB 060502A field (La Parola et al., GCN#5047) on May 3.21 (1.08 days post burst). At the location of the optical afterglow (Pool et al., GCN#5068), 0.7 arcsec outside the XRT borders (La Parola et al., GCN#5054), we detect a source with R = 22.5. Combined with the R-band magnitude reported by Hicken & Garnavich (GCN#5070), this implies a decay slope of alpha = 1.0.
An image of the field is shown at:
http://star-www.herts.ac.uk/~palli/grb060502A/grb060502A.jpg

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Jochen Greiner, last update: 02-Jun-2006 [Disclaimer]