Gamma-ray Burst 081230

(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 30 Dec 08 20:47:46 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     338633,   Seg_Num: 0
GRB_RA:           37.315d {+02h 29m 16s} (J2000),
                  37.416d {+02h 29m 40s} (current),
                  36.754d {+02h 27m 01s} (1950)
GRB_DEC:         -25.142d {-25d 08' 29"} (J2000),
                 -25.102d {-25d 06' 06"} (current),
                 -25.364d {-25d 21' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=3950 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 25-100 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        14830 TJD;   365 DOY;   08/12/30
GRB_TIME:        74172.62 SOD {20:36:12.62} UT
GRB_PHI:         -14.14 [deg]
GRB_THETA:        18.47 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    16.75 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  +1  +0  +0 +20  +0 
SUN_POSTN:       280.38d {+18h 41m 31s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.33d {+21h 13m 20s}  -15.45d {-15d 26' 46"}
MOON_DIST:        73.84 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.29,-67.99 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       24.92,-37.45 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 16.66,11.40 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 20:48:37 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     338633,   Seg_Num: 0
GRB_RA:           37.3315d {+02h 29m 19.5s} (J2000),
                  37.4325d {+02h 29m 43.8s} (current),
                  36.7701d {+02h 27m 04.8s} (1950)
GRB_DEC:         -25.1466d {-25d 08' 47.7"} (J2000),
                 -25.1068d {-25d 06' 24.4"} (current),
                 -25.3688d {-25d 22' 07.6"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       112 [cnts]
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74296.70 SOD {20:38:16.70} UT,   124.1 [sec] since BAT Trigger Time
CENTROID_X:      314.17,  raw= 314  [pixels]
CENTROID_Y:      311.61,  raw= 312  [pixels]
ROLL:            237.03 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   32.09
GRB_POS_XRT_Z:   27.98
IMAGE_URL:       sw00338633000msxps_rw.img
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.26 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.34d {+21h 13m 22s}  -15.44d {-15d 26' 36"}
MOON_DIST:        73.85 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.31,-67.98 [deg] galactic lon,lat of the burst
ECL_COORDS:       24.93,-37.46 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 20:48:43 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     338633,   Seg_Num: 0
GRB_RA:           37.3315d {+02h 29m 19.5s} (J2000),
                  37.4325d {+02h 29m 43.8s} (current),
                  36.7701d {+02h 27m 04.8s} (1950)
GRB_DEC:         -25.1466d {-25d 08' 47.7"} (J2000),
                 -25.1068d {-25d 06' 24.4"} (current),
                 -25.3688d {-25d 22' 07.6"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       112 [cnts]
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74296.70 SOD {20:38:16.70} UT,   124.1 [sec] since BAT Trigger Time
CENTROID_X:      314.17,  raw= 314  [pixels]
CENTROID_Y:      311.61,  raw= 312  [pixels]
ROLL:            237.03 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   32.09
GRB_POS_XRT_Z:   27.98
IMAGE_URL:       sw00338633000msxps_rw.img
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.26 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.34d {+21h 13m 22s}  -15.44d {-15d 26' 35"}
MOON_DIST:        73.85 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.31,-67.98 [deg] galactic lon,lat of the burst
ECL_COORDS:       24.93,-37.46 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 20:48:27 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     338633,   Seg_Num: 0
GRB_RA:           37.3315d {+02h 29m 19.55s} (J2000),
                  37.4325d {+02h 29m 43.80s} (current),
                  36.7701d {+02h 27m 04.82s} (1950)
GRB_DEC:         -25.1466d {-25d 08' 47.7"} (J2000),
                 -25.1068d {-25d 06' 24.4"} (current),
                 -25.3688d {-25d 22' 07.6"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.18e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.58 [sigma]
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74296.70 SOD {20:38:16.70} UT,   124.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.23 261.51 243.61
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.26 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.34d {+21h 13m 21s}  -15.44d {-15d 26' 38"}
MOON_DIST:        73.85 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.31,-67.98 [deg] galactic lon,lat of the burst
ECL_COORDS:       24.93,-37.46 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.93 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 30 Dec 08 20:49:29 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     338633,   Seg_Num: 0
GRB_RA:           37.315d {+02h 29m 16s} (J2000),
                  37.416d {+02h 29m 40s} (current),
                  36.754d {+02h 27m 01s} (1950)
GRB_DEC:         -25.142d {-25d 08' 29"} (J2000),
                 -25.102d {-25d 06' 06"} (current),
                 -25.364d {-25d 21' 49"} (1950)
GRB_DATE:        14830 TJD;   365 DOY;   08/12/30
GRB_TIME:        74172.62 SOD {20:36:12.62} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -14.14 [deg]
GRB_THETA:        18.47 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    16.75 [sigma]
LC_URL:          sw00338633000msb.lc
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.35d {+21h 13m 23s}  -15.44d {-15d 26' 26"}
MOON_DIST:        73.83 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.29,-67.99 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       24.92,-37.45 [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 = 16.66,11.40 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 20:50:34 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.319d {+02h 29m 16s} (J2000)
POINT_DEC:       -25.143d {-25d 08' 33"} (J2000)
POINT_ROLL:      237.033d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74304.48 SOD {20:38:24.48} UT,   131.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.500
N_STARS:         26
X_OFFSET:        264 [pixels]
Y_OFFSET:        336 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1775 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00338633000msufc0131.fits
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 39"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.36d {+21h 13m 25s}  -15.44d {-15d 26' 14"}
MOON_DIST:        73.83 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.30,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 20:51:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.319d {+02h 29m 16s} (J2000)
POINT_DEC:       -25.143d {-25d 08' 33"} (J2000)
POINT_ROLL:      237.033d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74304.48 SOD {20:38:24.48} UT,   131.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.500
N_STARS:         26
X_OFFSET:        264 [pixels]
Y_OFFSET:        336 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1775 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00338633000msufc0131.fits
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 38"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.36d {+21h 13m 27s}  -15.44d {-15d 26' 06"}
MOON_DIST:        73.82 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.30,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.45 [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 30 Dec 08 20:51:39 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.319d {+02h 29m 16s} (J2000)
POINT_DEC:       -25.143d {-25d 08' 33"} (J2000)
ROLL:            237.033d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74304.48 SOD {20:38:24.48} UT,   131.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     252362307
X_OFFSET:        723 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       883
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00338633000msuni0131.fits
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 38"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.36d {+21h 13m 27s}  -15.43d {-15d 26' 01"}
MOON_DIST:        73.82 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.30,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.45 [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 30 Dec 08 20:52:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.319d {+02h 29m 16s} (J2000)
POINT_DEC:       -25.143d {-25d 08' 33"} (J2000)
ROLL:            237.033d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  74304.48 SOD {20:38:24.48} UT,   131.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     252362307
X_OFFSET:        723 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       883
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00338633000msuni0131.fits
SUN_POSTN:       280.38d {+18h 41m 32s}  -23.09d {-23d 05' 38"}
SUN_DIST:        102.25 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.37d {+21h 13m 28s}  -15.43d {-15d 25' 56"}
MOON_DIST:        73.82 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.30,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.45 [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 #8753
V. La Parola (INAF-IASFPA), S. D. Barthelmy (GSFC), P. J. Brown (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), W.B Landsman (GSFC), V. Mangano (INAF-IASFPA), J. P. Osborne (U Leicester), K. L. Page (U Leicester), B. Sbarufatti (INAF-IASFPA) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 20:36:12 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081230 (trigger=338633). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 37.315, -25.142 which is
```
   RA(J2000) = 02h 29m 16s
   Dec(J2000) = -25d 08' 29"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 50 sec. The peak count rate was ~600 counts/sec (15-350 keV), at ~50 sec after the trigger.
The XRT began observing the field at 20:38:16.7 UT, 124.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 37.33148, -25.14645 which is equivalent to:
```
   RA(J2000)  = 02h 29m 19.56s
   Dec(J2000) = -25d 08' 47.2"
```
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 56 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.68e+20 cm^-2, Kalberla et al. 2005), with an excess column of 3.2 (+2.81/-2.34) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 250 seconds with the U filter starting 132 seconds after the BAT trigger. No credible 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 typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is V. La Parola (laparola AT ifc.inaf.it). 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 Circular #8754
F. Yuan (U Mich), E.S. Rykoff (UCSB), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 081230 (Swift trigger 338633). The first image was at 20:47:53.4 UT, 700.8 s after the burst (8.4 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 19.1 magnitude, steady source in the XRT error box with coordinates:
02:29:19.35 -25:08:49.22 (J2000), with positional
uncertainty of 1" or better
```
start UT    	mag     mlim(of image)
----------------------------------
20:49:23.0     19.1     19.2
```
This source is not visible in DSS (second epoch), 2MASS or the MPChecker database.
A jpeg image is available at http://www.rotse.net/images/gsb338633_3c021-030_key.jpg
Continuing observations are in progress.
GCN Circular #8755
S. T. Holland (CRESST/GSFC/USRA), P. J. Brown (PSU), and V. La Parola (INAF-IASFPA) report on the behalf of the Swift UVOT team:
The Swift/UVOT detects a faint source in the XRT error circle for GRB 081230 (La Parola, et al. 2008, GCN Circ. 8753). The source has a preliminary position of
```
     RA (J2000)   02:29:19.48  =   37.33117 (deg)
     Dec (J2000) -25:08:48.5   =  -25.14682 (deg)
```
and a preliminary u-band magnitude of u = 20.6 +/- 0.3 mag in a 250 s exposure starting 131 s after the BAT trigger. The quoted magnitude has not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.01 mag (Schlegel, et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383, 627).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 21:47:09 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.312d {+02h 29m 15s} (J2000)
POINT_DEC:       -25.136d {-25d 08' 08"} (J2000)
POINT_ROLL:      237.027d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  78233.04 SOD {21:43:53.04} UT,   4060.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.575
N_STARS:         12
X_OFFSET:        361 [pixels]
Y_OFFSET:        450 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1409 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00338633000msufc4060.fits
SUN_POSTN:       280.43d {+18h 41m 42s}  -23.09d {-23d 05' 28"}
SUN_DIST:        102.22 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.81d {+21h 15m 14s}  -15.25d {-15d 15' 15"}
MOON_DIST:        73.49 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.28,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 21:47:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.312d {+02h 29m 15s} (J2000)
POINT_DEC:       -25.136d {-25d 08' 08"} (J2000)
POINT_ROLL:      237.027d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  78233.04 SOD {21:43:53.04} UT,   4060.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.575
N_STARS:         12
X_OFFSET:        361 [pixels]
Y_OFFSET:        450 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1409 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00338633000msufc4060.fits
SUN_POSTN:       280.43d {+18h 41m 42s}  -23.09d {-23d 05' 28"}
SUN_DIST:        102.22 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.82d {+21h 15m 16s}  -15.25d {-15d 15' 08"}
MOON_DIST:        73.48 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.28,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.44 [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 30 Dec 08 21:48:41 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.312d {+02h 29m 15s} (J2000)
POINT_DEC:       -25.136d {-25d 08' 08"} (J2000)
ROLL:            237.027d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  78233.04 SOD {21:43:53.04} UT,   4060.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     252366236
X_OFFSET:        680 [pixels]
Y_OFFSET:        769 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       929
BINNING_INDEX:   1
IM_URL:          sw00338633000msuni4060.fits
SUN_POSTN:       280.43d {+18h 41m 43s}  -23.09d {-23d 05' 28"}
SUN_DIST:        102.22 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.82d {+21h 15m 17s}  -15.25d {-15d 14' 57"}
MOON_DIST:        73.48 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.28,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Dec 08 21:49:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     338633,   Seg_Num: 0
POINT_RA:         37.312d {+02h 29m 15s} (J2000)
POINT_DEC:       -25.136d {-25d 08' 08"} (J2000)
ROLL:            237.027d
IMG_START_DATE:  14830 TJD;   365 DOY;   08/12/30
IMG_START_TIME:  78233.04 SOD {21:43:53.04} UT,   4060.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     252366236
X_OFFSET:        680 [pixels]
Y_OFFSET:        769 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       929
BINNING_INDEX:   1
IM_URL:          sw00338633000msuni4060.fits
SUN_POSTN:       280.43d {+18h 41m 43s}  -23.09d {-23d 05' 28"}
SUN_DIST:        102.22 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      318.83d {+21h 15m 18s}  -15.25d {-15d 14' 53"}
MOON_DIST:        73.48 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:      213.28,-67.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       24.92,-37.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #8756
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1640 s of XRT Photon Counting mode data and 4 UVOT images for GRB 081230, 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 = 37.3314, -25.1477 which is equivalent to:
```
RA (J2000): 02h 29m 19.53s
Dec (J2000): -25d 08' 51.8"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), 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 #8757
S. R. Oates (MSSL-UCL) and V. La Parola (INAF-IASFPA) report on behalf of the Swift/UVOT team:
The Swift/UVOT began observerving the field of GRB 081230 132 s after the BAT trigger ( La Parola et al., GCN Circ. 8753). We detect the optical afterglow in the white, v, b and u filters at the position:
```
RA(J2000.0)  = 02:29:19.467
DEC(J2000.0) = -25:08:51.0
```
with an estimated uncertainty of 0.9 arcsec (radius, 90% confidence). This position is consistent with the UVOT-enhanced XRT position (Osborne et al., GCN 8756) and the optical afterglow position reported by ROTSE-III (Yuan et al., GCN 8754).
The magnitudes and 3 sigma upper limits are reported below:
```
Filter    T_start (s) T_stop  Exposure    Mag/3sig UL
------------------------------------------------------------
white       4060  4210   147   20.45 +/- 0.35
v	         587    607     19     18.30 +/- 0.48
b	         388    408     19     18.92 +/- 0.36
u	         132    382     246   20.28 +/- 0.38
u	         511    531 	19     19.04 +/- 0.52
uvw1	 487    5854   435   > 21.23
uvm2       462    5649   255   > 20.95
uvw2       414	    6575   353   > 21.44
------------------------------------------------------------
```
The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.01 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383,627).
GCN Circular #8758
V. La Parola, B. Sbarufatti, V. Mangano (INAF-IASF Pa) report on behalf of the Swift XRT team:
We have analysed the first 35 ks of XRT observations for GRB 081230 (La Parola et al. GCN Circ 8753), with an exposure time of 104 s in WT mode and 11.4 ks in PC mode. The astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 37.3314 -25.1477, corresponding to:
```
RA (J2000): 02h 29m 19.53s
Dec (J2000): -25d 08' 51.8
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence, Osborne et al. GCN Circ 8756).
The lightcurve can be fitted with a broken power-law with the following parameters:
```
alpha1=-6.910+/-0.007
T_break=298+/-9
alpha2=-0.62+/-0.5
```
There is evidence for a late flare a peaking at 5000s.
The spectrum of the data collected in WT mode can be fitted with a powerlaw with photon index Gamma = 1.96 +/- 0.11, absorbed by the Galactic column in this direction of 1.7x10^20 cm^-2, plus an intrinsic column of (6.4+/-2.2)x10^20 cm^-2. The observed (unabsorbed) flux over this time is 1.03x10^-9 (1.3x10^-9) erg cm^-2 s^-1, corresponding to a counts to observed flux conversion of 4.1x10^-11 erg cm^-2 count^-1. The spectrum of the data collected in PC mode can be fitted with a powerlaw with photon index Gamma = 2.14 (+0.10,-0.20), with an intrinsic column of (5.3 [+2.2,-3.7])x10^20 cm^-2. The observed (unabsorbed) flux over this time is 2.1x10^-12 (2.7x10^-9) erg cm^-2 s^-1,
With the present decay law, the count rate at 24 hours is predicted to be 1.1x10^-2 c/s (corresponding to an observed flux of 3.7x10^-13 erg cm^-2 s^-1)
This circular is an official product of the Swift-XRT team.
GCN Circular #8759
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), V. La Parola (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-300 to T+1197 sec from the recent telemetry downlink, we report further analysis of BAT GRB 081230 (trigger #338633) (La Parola, et al., GCN Circ. 8753). The BAT ground-calculated position is RA, Dec = 37.330, -25.145 deg which is
```
   RA(J2000)  =  02h 29m 19.2s 
   Dec(J2000) = -25d 08' 42.6" 
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve consists of a series of overlapping peaks ranging from T+5 sec to T+70 sec, with the strongest emission at ~T+50 seconds. T90 (15-350 keV) is 60.7 +- 13.8 sec (estimated error including systematics).
The time-averaged spectrum from T-14.4 to T+62.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.97 +- 0.16. The fluence in the 15-150 keV band is 8.2 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+46.63 sec in the 15-150 keV band is 0.7 +- 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/338633/BA/
GCN Circular #8760
GRB 081230: GROND confirmation of the afterglow
P. Afonso (MPE), C. Clemens (MPE), S. Klose (Tautenburg), J. Greiner (MPE) and G. Szokoly (Eotvos Univ. Budapest) report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile) imaged the field of GRB 081230 (Swift trigger 338633, La Parola et al., GCN #8753) simultaneously in g'r'i'z'JHK bands
We detected and confirm the afterglow candidate in all bands, at the position:
```
RA(J2000): 02:29:19.51
DEC(J2000): -25:08:49.95 
```
with uncertainties of 0.5" in each coordinate.
This position is compatible with UVOT (Oates et alia, GCN #8757) and ROTSE-III (Yuan et alia, GCN #8754) reported positions.
Observations started on Dec. 31 at 00h48 UT, 15123 seconds, or ~ 4.2 hours after the burst.
We used 4 images of 375 s exposure in g'r'i'z' and 120 images of 10s exposure in JHK, for each epoch.
The images mid time for the 1st epoch is 5.99h (or 21564 seconds) after the burst. Observations were done at an average air mass = 1.128 and seeing ~ 1.5''.
We took a 2nd epoch on January 1st, 2009, starting at 03h21 UT.
The images mid time for the 2nd epoch is 30.99h (or 111564 seconds) after the burst. Observations were done at an average air mass = 1.334 and seeing ~ 1.3''.
The preliminary data for the 2nd epoch clearly confirms the fading of the afterglow:
We present preliminary photometric results for g'r'i'z'. The AB magnitudes, using GROND zero points are as follows:
```
     1st epoch       2nd epoch 

g' = 21.32 +- 0.02   23.67 +- 0.08
r' = 20.96 +- 0.01   23.07 +- 0.06
i' = 20.74 +- 0.02   22.79 +- 0.09
z' = 20.66 +- 0.03   22.84 +- 0.17 
```
No correction for galactic extinction was done.
The quoted error is statistical only. There is an additional systematic error in the absolute calibration using the GROND zeropoints which is expected to be in the 0.2 mag range.
Further data analysis is ongoing for JHK - the aftegrlow being clearly visible on the first epoch, but not on the 2nd.
GCN Report 196.1
GCN_Report 196.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_196_1.pdf by V. La Parola at INAF-IASFPa titled: "Final Observations on Swift GRB 081230"
1011.1205 from 5 Nov 10
T. Kr�hler et al.: Photometric redshifts for GRB afterglows from GROND and Swift/UVOT
We present a framework to obtain photometric redshifts (photo-zs) for gamma-ray burst afterglows. Using multi-band photometry from GROND and Swift/UVOT, photo-zs are derived for five GRBs for which spectroscopic redshifts are not available. We use UV/optical/NIR data and synthetic photometry based on afterglow observations and theory to derive the photometric redshifts of GRBs and their accuracy. Taking into account the afterglow synchrotron emission properties, we investigate the application of photometry to derive redshifts in a theoretical range between z~1 and z~12. The measurement of photo-zs for GRB afterglows provides a quick, robust and reliable determination of the distance scale to the burst, particularly in those cases where spectroscopic observations in the optical/NIR range cannot be obtained. Given a sufficiently bright and mildly reddened afterglow, the relative photo-z accuracy is better than 10% between z=1.5 and z~7 and better than 5% between z=2 and z=6. We detail the approach on 5 sources without spectroscopic redshifts observed with UVOT on-board Swift and/or GROND. The distance scale to those same afterglows is measured to be $z=4.31^{+0.14}_{-0.15}$ for GRB 080825B, $z=2.13^{+0.14}_{-0.20}$ for GRB 080906, $z=3.44^{+0.15}_{-0.32}$ for GRB 081228, $z=2.03^{+0.16}_{-0.14}$ for GRB 081230 and $z=1.28^{+0.16}_{-0.15}$ for GRB 090530. Combining the response from UVOT with ground-based observatories and in particular GROND operating in the optical/NIR wavelength regime, reliable photo-zs can be obtained from z ~ 1.0 out to z ~ 10, and possibly even at higher redshifts in some favorable cases, provided that these GRBs exist, are localized quickly, have sufficiently bright afterglows and are not heavily obscured.

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Jochen Greiner, last update: 05-Nov-2010 [Disclaimer]