Gamma-ray Burst 080506

(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 May 08 17:47:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.435d {+21h 57m 44s} (J2000),
                 329.522d {+21h 58m 05s} (current),
                 328.909d {+21h 55m 38s} (1950)
GRB_DEC:         +39.002d {+39d 00' 08"} (J2000),
                 +39.042d {+39d 02' 32"} (current),
                 +38.763d {+38d 45' 48"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1476 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        14592 TJD;   127 DOY;   08/05/06
GRB_TIME:        63981.22 SOD {17:46:21.22} UT
GRB_PHI:         -19.38 [deg]
GRB_THETA:        37.49 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.18 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -3  +0  +0 -38  +1 
SUN_POSTN:        44.09d {+02h 56m 22s}  +16.79d {+16d 47' 11"}
SUN_DIST:         67.68 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.20d {+04h 04m 48s}  +25.80d {+25d 48' 14"}
MOON_DIST:        75.30 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.48, 47.27 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 158.84,0.66 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:49:24 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.4215d {+21h 57m 41.1s} (J2000),
                 329.5093d {+21h 58m 02.2s} (current),
                 328.8960d {+21h 55m 35.0s} (1950)
GRB_DEC:         +38.9853d {+38d 59' 07.0"} (J2000),
                 +39.0253d {+39d 01' 31.1"} (current),
                 +38.7463d {+38d 44' 46.5"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       139 [cnts]
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64121.31 SOD {17:48:41.31} UT,   140.1 [sec] since BAT Trigger Time
CENTROID_X:      318.82,  raw= 319  [pixels]
CENTROID_Y:      275.08,  raw= 275  [pixels]
ROLL:            85.96 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -54.01
GRB_POS_XRT_Z:   38.96
IMAGE_URL:       sw00311159000msxps_rw.img
SUN_POSTN:        44.09d {+02h 56m 22s}  +16.79d {+16d 47' 12"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.22d {+04h 04m 52s}  +25.81d {+25d 48' 26"}
MOON_DIST:        75.33 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.75,-12.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      350.45, 47.27 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:49:14 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.4215d {+21h 57m 41.1s} (J2000),
                 329.5093d {+21h 58m 02.2s} (current),
                 328.8960d {+21h 55m 35.0s} (1950)
GRB_DEC:         +38.9853d {+38d 59' 07.0"} (J2000),
                 +39.0253d {+39d 01' 31.1"} (current),
                 +38.7463d {+38d 44' 46.5"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.50e-09 [erg/cm2/sec]
GRB_SIGNIF:      11.78 [sigma]
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64121.31 SOD {17:48:41.31} UT,   140.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.60 237.24 261.19 243.50
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        44.09d {+02h 56m 22s}  +16.79d {+16d 47' 12"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.22d {+04h 04m 52s}  +25.81d {+25d 48' 25"}
MOON_DIST:        75.33 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.75,-12.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      350.45, 47.27 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.19 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:49:30 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.4215d {+21h 57m 41.1s} (J2000),
                 329.5093d {+21h 58m 02.2s} (current),
                 328.8960d {+21h 55m 35.0s} (1950)
GRB_DEC:         +38.9853d {+38d 59' 07.0"} (J2000),
                 +39.0253d {+39d 01' 31.1"} (current),
                 +38.7463d {+38d 44' 46.5"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       139 [cnts]
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64121.31 SOD {17:48:41.31} UT,   140.1 [sec] since BAT Trigger Time
CENTROID_X:      318.82,  raw= 319  [pixels]
CENTROID_Y:      275.08,  raw= 275  [pixels]
ROLL:            85.96 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -54.01
GRB_POS_XRT_Z:   38.96
IMAGE_URL:       sw00311159000msxps_rw.img
SUN_POSTN:        44.09d {+02h 56m 22s}  +16.79d {+16d 47' 12"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.22d {+04h 04m 53s}  +25.81d {+25d 48' 26"}
MOON_DIST:        75.33 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.75,-12.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      350.45, 47.27 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:50:21 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.435d {+21h 57m 44s} (J2000),
                 329.522d {+21h 58m 05s} (current),
                 328.909d {+21h 55m 38s} (1950)
GRB_DEC:         +39.002d {+39d 00' 08"} (J2000),
                 +39.042d {+39d 02' 32"} (current),
                 +38.763d {+38d 45' 48"} (1950)
GRB_DATE:        14592 TJD;   127 DOY;   08/05/06
GRB_TIME:        63981.22 SOD {17:46:21.22} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -19.38 [deg]
GRB_THETA:        37.49 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.18 [sigma]
LC_URL:          sw00311159000msb.lc
SUN_POSTN:        44.09d {+02h 56m 22s}  +16.79d {+16d 47' 13"}
SUN_DIST:         67.68 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.23d {+04h 04m 55s}  +25.81d {+25d 48' 32"}
MOON_DIST:        75.32 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.48, 47.27 [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 an image 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 = 158.84,0.66 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:58:12 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     311159,   Seg_Num: 0
POINT_RA:        329.434d {+21h 57m 44s} (J2000)
POINT_DEC:       +39.001d {+39d 00' 03"} (J2000)
POINT_ROLL:      85.965d
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64124.35 SOD {17:48:44.35} UT,   143.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.859
N_STARS:         190
X_OFFSET:        471 [pixels]
Y_OFFSET:        700 [pixels]
X_MAX:           1430 [pixels]
Y_MAX:           1659 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00311159000msufc0143.fits
SUN_POSTN:        44.10d {+02h 56m 24s}  +16.79d {+16d 47' 18"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.32d {+04h 05m 17s}  +25.82d {+25d 49' 25"}
MOON_DIST:        75.38 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      350.48, 47.27 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 17:58:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     311159,   Seg_Num: 0
POINT_RA:        329.434d {+21h 57m 44s} (J2000)
POINT_DEC:       +39.001d {+39d 00' 03"} (J2000)
POINT_ROLL:      85.965d
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64124.35 SOD {17:48:44.35} UT,   143.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.859
N_STARS:         190
X_OFFSET:        471 [pixels]
Y_OFFSET:        700 [pixels]
X_MAX:           1430 [pixels]
Y_MAX:           1659 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00311159000msufc0143.fits
SUN_POSTN:        44.10d {+02h 56m 24s}  +16.79d {+16d 47' 19"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.33d {+04h 05m 19s}  +25.83d {+25d 49' 30"}
MOON_DIST:        75.38 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      350.48, 47.27 [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 May 08 17:59:35 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     311159,   Seg_Num: 0
POINT_RA:        329.434d {+21h 57m 44s} (J2000)
POINT_DEC:       +39.001d {+39d 00' 03"} (J2000)
ROLL:            85.965d
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64124.35 SOD {17:48:44.35} UT,   143.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     231788927
X_OFFSET:        791 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       951
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw00311159000msuni0143.fits
SUN_POSTN:        44.10d {+02h 56m 24s}  +16.79d {+16d 47' 19"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.34d {+04h 05m 21s}  +25.83d {+25d 49' 34"}
MOON_DIST:        75.39 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      350.48, 47.27 [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 May 08 18:00:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     311159,   Seg_Num: 0
POINT_RA:        329.434d {+21h 57m 44s} (J2000)
POINT_DEC:       +39.001d {+39d 00' 03"} (J2000)
ROLL:            85.965d
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64124.35 SOD {17:48:44.35} UT,   143.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     231788927
X_OFFSET:        791 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       951
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw00311159000msuni0143.fits
SUN_POSTN:        44.10d {+02h 56m 24s}  +16.79d {+16d 47' 19"}
SUN_DIST:         67.69 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.34d {+04h 05m 22s}  +25.83d {+25d 49' 37"}
MOON_DIST:        75.39 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.77,-12.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      350.48, 47.27 [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 #7685
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), M. M. Chester (PSU), G. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), C. Guidorzi (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), C. Pagani (PSU), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), M. Stamatikos (NASA/ORAU), T. N. Ukwatta (GSFC/GWU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 17:46:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080506 (trigger=311159). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 329.435, +39.002 which is
```
   RA(J2000) = 21h 57m 44s
   Dec(J2000) = +39d 00' 08"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As this is an image trigger, the BAT light curve does not show meaningful emission from the burst.
The XRT began observing the field at 17:48:41.3 UT, 140.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 329.42145, 38.98413 which is equivalent to:
```
   RA(J2000)  = 21h 57m 41.15s
   Dec(J2000) = +38d 59' 02.9"
```
with an uncertainty of 3.3 arcseconds (radius, 90% containment). This location is 74 arcseconds from the BAT onboard position, within the BAT error circle. The XRT light curve from TDRSS data is fading.
A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density, so we cannot provide limits on the redshift using spectroscopy and the relation from Grupe et al. (2007). A summary of the promptly downlinked data is given at http://www.swift.ac.uk/sper/311159/.
The initial flux in the 2.5 s image was 5.50e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 400 seconds with the V filter starting 143 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	21:57:41.83 = 329.4243
  DEC(J2000) = +38:59:06.4  =  38.9851
```
with a 1-sigma error radius of about 0.5 arc sec. This position is 8.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.3 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction of about 0.8 magnitudes.
Burst Advocate for this burst is W. H. Baumgartner (wayne 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:     Tue 06 May 08 18:07:49 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.4229d {+21h 57m 41.4s} (J2000),
                 329.5107d {+21h 58m 02.5s} (current),
                 328.8974d {+21h 55m 35.3s} (1950)
GRB_DEC:         +38.9849d {+38d 59' 05.6"} (J2000),
                 +39.0249d {+39d 01' 29.7"} (current),
                 +38.7459d {+38d 44' 45.1"} (1950)
GRB_ERROR:       2.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64304.00 SOD {17:51:44.00} UT,   322.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        44.11d {+02h 56m 25s}  +16.79d {+16d 47' 25"}
SUN_DIST:         67.70 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.43d {+04h 05m 43s}  +25.84d {+25d 50' 30"}
MOON_DIST:        75.46 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.75,-12.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      350.45, 47.26 [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.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 May 08 18:09:39 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     311159,   Seg_Num: 0
GRB_RA:          329.4243d {+21h 57m 41.83s} (J2000),
                 329.5121d {+21h 58m 02.90s} (current),
                 328.8988d {+21h 55m 35.71s} (1950)
GRB_DEC:         +38.9851d {+38d 59' 06.3"} (J2000),
                 +39.0251d {+39d 01' 30.4"} (current),
                 +38.7461d {+38d 44' 45.8"} (1950)
GRB_ERROR:       0.4 [arcsec radius, statistical only]
GRB_MAG:         18.29 +/- 0.50 [mag]
FILTER:          3, V
IMG_START_DATE:  14592 TJD;   127 DOY;   08/05/06
IMG_START_TIME:  64126.00 SOD {17:48:46.00} UT,   144.8 [sec] since BAT Trigger Time
SUN_POSTN:        44.11d {+02h 56m 26s}  +16.79d {+16d 47' 26"}
SUN_DIST:         67.70 [deg]   Sun_angle= 5.0 [hr] (West of Sun)
MOON_POSTN:       61.45d {+04h 05m 48s}  +25.85d {+25d 50' 42"}
MOON_DIST:        75.47 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:       89.75,-12.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.46, 47.26 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 7.6 arcsec from the XRT position.  
COMMENTS:        The updated XRT position is 4 arcsecs from UVOT's.

GCN Circular #7686
K. S. Kawabata, M. Sasada, M. Uemura, T. Yamashita and T. Ohsugi (Hiroshima Univ.) and R. G. Lundock (Tohoku Univ.) report on behalf of KANATA/TRISPEC observation team:
We performed a series of simultaneous optical(Rc) and NIR (J, Ks) imaging observations for the optical counterpart associated with GRB 080506 (Baumgartner et al, GCN 7685) using TRISPEC attached to the 1.5-m KANATA telescope. Our quick-look analysis showed that Rc magnitude of the counterpart was 17.5 at 220 sec after the BAT trigger. It then faded and reached 19.5 at ~5050 sec. We used USNO A2.0 1275-16800533 (R=15.1) and 1275-16801542 (R=15.1) stars for comparison. Further analysis is ongoing.
GCN Circular #7687
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 221 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080506, 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 = 329.42431, +38.98470 which is equivalent to:
```
RA (J2000): 21h 57m 41.83s
Dec (J2000): +38d 59' 04.9"
```
with an uncertainty of 1.5 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), the current algorithm is an extension of this method.
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #7688
D. A. Kann, C. Hoegner and S. Ertel (TLS Tautenburg) report:
We observed the afterglow of Swift GRB 080506 (Baumgartner et al., GCN 7685, Kawabata et al., GCN 7686) with the Tautenburg 1.34m Schmidt telescope 0.32 days after the GRB in good conditions (moderate transparency but excellent seeing). We obtained a total of six 600 sec exposures, in the sequence Rc, V, Ic, Z, Z, Z before twilight forced us to shut down. The afterglow is well (Rc, V, Ic) and faintly (Z) detected in single images, and well detected in the 1800 sec stack of the three Z images.
We find an afterglow position
```
R.A. (J2000) = 21:57:41.775
Dec. (J2000) = +38:59:05.86
```
in comparison with the USNOB1.0 catalog, with a precision of 0".5 in each coordinate. This is fully in agreement with the UVOT (Baumgartner et al., GCN 7685) and enhanced XRT (Osborne et al., GCN 7687) positions.
Assuming the star at
```
R.A. (J2000) = 21:57:39.84
Dec. (J2000) = +38:58:28.25
```
to have Rc = 16.7 (magnitude is basically identical in R1 and R2 magnitudes), we find for the afterglow:
```
time	Rc	dRc

0.31576	20.77	0.13
```
Taking the two measurements from Kawabata et al. (GCN 7686), we find a shallow decay slope of alpha = 0.6 between 0.0025 and 0.316 days after the GRB.
Our (and Swift's) clear detection in the V band implies z <~ 4. On the other hand, this was an image trigger, with faint emission seen up to ~ 200 seconds. The initial XRT light curve (XRT repository, Evans et al. 2007) is flat until 200 seconds before dropping off very steeply. This may suggest that this GRB lies at moderately high redshift (3 - 4). Spectroscopy is encouraged.
This message may be cited.
GCN Circular #7689
M. Kocka, M. Nekola, J. Strobl, R. Hudec, C. Polasek (AsU AV CR, Ondrejov), M. Jelinek, P. Kubanek (IAA CSIC, Granada), F. Munz (IASF/INAF, Bologna) A. de Ugarte Postigo (ESO) report
We observed the OT of the GRB080506 (Baumgartner et al, GCN 7685) with the 0.5m telescope at ASU Ondrejov in Czech Republic. We obtained a set of R-band exposures at ~7.1h after the GRB.
Using the same calibration as Kawabata et al. (GCN 7686) we find the brightness R ~ 21.2+-0.4.
This message may be cited.
GCN Circular #7690
A. de Ugarte Postigo (ESO), C. C. Thoene, J. P. U. Fynbo (DARK/NBI), E. Leitet (Uppsala Univ.) and L. M. Trinchant (Stockholm Univ.) report on behalf of a larger collaboration:
We have observed the field of GRB 080506 (Baumgartner et al., GCN 7685) using the 2.5m NOT telescope (+ALFOSC) at Roque de Los Muchachos Observatory, in La Palma (Spain) using U, B and R filters. A 300s R-band observation with mid exposure time 7.1518 May 2008 UT (9.87hr after the burst) reveals the object at a magnitude of 21.05 =B1 0.11, using the reference stars given in GCN 7686 for calibration. Combining this datapoint with those of Kawabata et al. (GCN 7686), Kann et al. (GCN 7688) and Kocka et al. (GCN 7689, where it should say R=3D 20.2+/-0.4, private communication) we measure a decay rate of alpha =3D 0.64 =B1 0.02 (f~t^-alpha), consistent with the value reported by Kann et al. The object is clearly detected in all filters, including the U-band frame, implying a redshift < 3.
GCN Circular #7692
K. McLean (GSFC/UMD), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+903 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080506 (trigger #311159) (Baumgartner, et al., GCN Circ. 7685). The BAT ground-calculated position is RA, Dec = 329.467, 38.961 deg, which is
```
   RA(J2000)  =  21h 57m 52.1s 
   Dec(J2000) = +38d 57' 40.0" 
```
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%.
The mask-weighted light curve shows two episodes of emission, the first starting at ~T+20 sec, peaking at ~T+40 sec, and returning to background at ~T+90 sec. The second episode starts at ~T+100 sec, peaks at ~T+150 sec, and ends at ~T+200 sec. T90 (15-350 keV) is 150 +- 20 sec (estimated error including systematics).
The time-averaged spectrum from T+25.8 to T+188.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.87 +- 0.19. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+134.48 sec in the 15-150 keV band is 0.4 +- 0.1 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/311159/BA/
This burst satisfies Sakamoto/Ukwatta Swift-BAT possible high-z criteria (Ukwatta et al. arXiv:0802.3815):
```
1) PL photon index = 1.87          (PL photon index < 2)
2) 1-s peak photon flux = 0.4      (1-s peak photon flux < 1.0 ph/cm2/s)
3) Light curve variance = 6.2x10-6 (Variance < 0.0001)
4) T90/(Peak photon flux) = 403    (T90/(Peak photon flux) > 100)
```
Based on a limited sample of bursts, these criteria yield an 85% chance it has a redshift greater than 3.5.
GCN Circular #7693
S.R. Oates (MSSL/UCL) and W. Baumgartner (NASA/GSFC) report on behalf of the Swift/UVOT team
The Swift/UVOT began settled observations of the field of GRB 080506, 143s after the BAT trigger (Baumgartner et al., GCN 7685). We detect the afterglow in the v and b filters at the position:
```
RA(J2000.0)  =   21:57:41.84
DEC(J2000.0) =  +38:59:06.1
```
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence). This position is consistent with the UVOT enhanced XRT position (Osborne et al., GCN 7687) and the TLS position (Kann et al., GCN 7688).
No observations were performed with the white filter due to the presence of 7.5mag B star (HD 208837) 6 arcmins from the GRB position.
UVOT magnitudes and 3 sigma upper limits are reported below for the single and coadded images:
```
Filter    Tstart(s)  Tstop   Expo(s)   Magnitude/3sigUL
-----------------------------------------------------
v            143     543     393       18.35 +/- 0.10
v           6728    6928     197       19.88 +/- 0.52
b            623     771      19       19.84 +/- 0.65 (1.7-sigma)
b          10818   11118     295       20.64 +/- 0.28 (3.8-sigma)
u            599    6311     254       > 20.29
w1           574    7338     471       > 20.44
m2          1284    7133     787       > 20.69
w2           639    6723     432       > 20.46
-----------------------------------------------------
```
These magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E{B-V} = 0.23 mag (Schlegel et al. 1998). The photometry is on the UVOT flight system described in Poole et al. (2008,MNRAS,383,627).
GCN Circular #7694
B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF PA) and W. H. Baumgartner (GSFC/UMBC)
The Swift-XRT began observing GRB 080506 (trigger=3D311159, Baumgartner et al., GCN Circ. 7685) in Window Timing mode, 146 s after the BAT trigger. The enhanced XRT position was given in Osborne et al. (GCN Circ. 7687).
The lightcurve is quite complex. It shows two initial bright flares centered at 182+/-2 s and 254+/-2 s, with folding times of 22+/-1 s and 88+/-2 s, respectively. Flaring activity is detected until times > T+10 ks. The decay slope after 10 ks from the trigger time is -0.6+/-0.2.
The spectrum of the first flare can be fit by a power-law model, with a photon index of 1.46 =B1 0.06 and column density consistent with the average Galactic column density in this direction of 1.66e21 cm-2 (Kalberla et al 2005). The observed (unabsorbed) 0.3-10 keV flux is 1.5e-9 (1.8e-9) erg cm-2 s-1.
The spectrum of the second flare can be fit by a power-law model, with a photon index of 2.3 =B1 0.1 and column density consistent with the average Galactic column density in this direction. The observed (unabsorbed) 0.3-10 keV flux is 3.2e-10 (5.2e-9) erg cm-2 s-1.
The PC mode spectrum, covering times > T+1000 s, is fit by a power law model with photon index 2.0 =B1 0.2 and no evidence for any additional column density with respect to the Galactic one. The corresponding observed (unabsorbed) 0.3-10 keV fluxes are 2.3e-12 (3.5e-12 ) erg cm-2 s-1, respectively.
If the burst continues to decay at the same rate, we predict an XRT count rate of 9.8 e-3 counts/s and 6.4 e-3 counts/s at T+24 hours and T+48 hours, respectively. This corresponds to observed 0.3-10 keV fluxes of approximately 5.4e-13 and 3.6e-13 erg cm-2 s-1.
This circular is an official product of the Swift-XRT team.
GCN Circular #7696
D. A. Kann, C. Hoegner, and S. Ertel (TLS Tautenburg) report:
We observed the afterglow of Swift GRB 080506 (Baumgartner et al., GCN 7685) with the Tautenburg 1.34m Schmidt telescope 1.33 days after the GRB, again in good conditions. We obtained a four 300 sec exposures in the Rc band before twilight shut us down. The afterglow is faintly detected in the stacked image.
Using the same comparison star as Kann et al. (GCN 7688), we find:
```
time (days)	Rc	dRc

1.3346		22.23	0.33
```
An extrapolation of the decay in the first 0.4 days (~0.63, Kann et al., GCN 7688, de Ugarte Postigo et al., GCN 7690) yields an expected magnitude of Rc ~ 21.8 at 1.33 days after the GRB. Our measured value lies below the extrapolation, indicating a break (possibly a jet break) may have occured. We caution that the detection is rather marginal and the high sky background may falsify the measurement.
This message may be cited.
GCN Circular #7698
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 080506 (GCN 7685) at a frequency of 8.46 GHz at 2008 May 8.53 UT. We do not detect the GRB afterglow at Swift-XRT position (GCN 7687). The flux density at the afterglow position is -40 +/- 40 uJy.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #7700
D.K. Sahu, G.C. Anupama (IIA, Bangalore), Kuntal Misra (ARIES) report.
The field of GRB 080506 (Baumgartner et al., GCN 7685) was observed using HFOSC mounted on the 2-m Himalayan Chandra Telescope, Indian Astronomical Observatory, India. A series of 300sec exposures were taken in R-band between 20:45 UT and 23:00 UT on 06/05/2008. The optical counter part is detected in all our frames. Using the calibration by Kawabata et al. (GCN 7686), the estimated R band magnitude of the optical counter part is 20.13+/-0.1 mag at 20:47UT. The optical counter part faded by ~ 0.6 magnitude during our observations.
This message may be cited.
GCN Circular #7709
S. Maeno, H. Naito, S. Narusawa and R. Iizuka report on behalf of NHAO.
We observed the field of GRB 080506 (GCN 7685) with MINT on the 2.0-m NAYUTA telescope at Nishi-Harima Astronomical Observatory, Japan. We detected the optical afterglow in R-band on 2008 May 6 17:58:02 UT (701 seconds after the BAT trigger).
The magnitudes relative to the USNO B1.0 catalog are below.
```
Start(UT) exp(sec) R-mag R-err
--------------------------------------------
02:58:02    150    18.23    0.11
03:03:51    240    18.22    0.12
03:14:22    300    18.51    0.13
03:32:29    300    18.95    0.13
03:53:52    450    19.26    0.13
04:10:55    450    19.64    0.21
--------------------------------------------
```

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Jochen Greiner, last update: 12-May-2008 [Disclaimer]