Gamma-ray Burst 120224A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:40:40 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     515976,   Seg_Num: 0
GRB_RA:           40.975d {+02h 43m 54s} (J2000),
                  41.117d {+02h 44m 28s} (current),
                  40.393d {+02h 41m 34s} (1950)
GRB_DEC:         -17.793d {-17d 47' 32"} (J2000),
                 -17.742d {-17d 44' 29"} (current),
                 -18.004d {-18d 00' 12"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       19296 [cnts]    Image_Peak=313 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   291     E_range: 15-50 keV
BKG_INTEN:       178932 [cnts]
BKG_TIME:        16736.07 SOD {04:38:56.07} UT
BKG_DUR:         40 [sec]
GRB_DATE:        15981 TJD;    55 DOY;   12/02/24
GRB_TIME:        16796.49 SOD {04:39:56.49} UT
GRB_PHI:         -113.57 [deg]
GRB_THETA:        35.55 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.84 [sigma]
IMAGE_SIGNIF:    7.80 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +1  -2  +0  +0 -46  +0 
SUN_POSTN:       336.81d {+22h 27m 14s}   -9.69d {-09d 41' 15"}
SUN_DIST:         62.72 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.01d {+23h 56m 02s}   +4.61d {+04d 36' 52"}
MOON_DIST:        47.17 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.04,-62.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       32.12,-31.92 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 171.24,19.78 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:41:53 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.002d {+02h 44m 00s} (J2000)
POINT_DEC:       -17.791d {-17d 47' 28"} (J2000)
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16905.60 SOD {04:41:45.60} UT,   109.1 [sec] since BAT Trigger Time
COUNTS:          4    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:43:38 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     515976,   Seg_Num: 0
GRB_RA:           40.975d {+02h 43m 54s} (J2000),
                  41.117d {+02h 44m 28s} (current),
                  40.393d {+02h 41m 34s} (1950)
GRB_DEC:         -17.793d {-17d 47' 32"} (J2000),
                 -17.742d {-17d 44' 29"} (current),
                 -18.004d {-18d 00' 12"} (1950)
GRB_DATE:        15981 TJD;    55 DOY;   12/02/24
GRB_TIME:        16796.49 SOD {04:39:56.49} UT
TRIGGER_INDEX:   291
GRB_PHI:         -113.57 [deg]
GRB_THETA:        35.55 [deg]
DELTA_TIME:      38.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.84 [sigma]
IMAGE_SIGNIF:    7.80 [sigma]
LC_URL:          sw00515976000msb.lc
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 12"}
SUN_DIST:         62.72 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.03d {+23h 56m 08s}   +4.62d {+04d 37' 25"}
MOON_DIST:        47.16 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.04,-62.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       32.12,-31.92 [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 = 171.24,19.78 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:44:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.002d {+02h 44m 00s} (J2000)
POINT_DEC:       -17.791d {-17d 47' 26"} (J2000)
POINT_ROLL:      268.112d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16911.12 SOD {04:41:51.12} UT,   114.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.012
N_STARS:         18
X_OFFSET:        644 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1603 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00515976000msufc0114.fits
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 11"}
SUN_DIST:         62.75 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.04d {+23h 56m 10s}   +4.63d {+04d 37' 37"}
MOON_DIST:        47.17 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:45:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.002d {+02h 44m 00s} (J2000)
POINT_DEC:       -17.791d {-17d 47' 26"} (J2000)
POINT_ROLL:      268.112d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16911.12 SOD {04:41:51.12} UT,   114.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.012
N_STARS:         18
X_OFFSET:        644 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1603 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00515976000msufc0114.fits
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 11"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.04d {+23h 56m 11s}   +4.63d {+04d 37' 42"}
MOON_DIST:        47.17 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 04:46:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.002d {+02h 44m 00s} (J2000)
POINT_DEC:       -17.791d {-17d 47' 26"} (J2000)
ROLL:            268.112d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16911.12 SOD {04:41:51.12} UT,   114.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     351751319
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0122.fits
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 10"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.05d {+23h 56m 12s}   +4.63d {+04d 37' 53"}
MOON_DIST:        47.17 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 04:46:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.002d {+02h 44m 00s} (J2000)
POINT_DEC:       -17.791d {-17d 47' 26"} (J2000)
ROLL:            268.112d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16911.12 SOD {04:41:51.12} UT,   114.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     351751319
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0122.fits
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 09"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.06d {+23h 56m 13s}   +4.63d {+04d 37' 57"}
MOON_DIST:        47.16 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:46:44 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     515976,   Seg_Num: 0
GRB_RA:           40.9438d {+02h 43m 46.51s} (J2000),
                  41.0852d {+02h 44m 20.45s} (current),
                  40.3617d {+02h 41m 26.81s} (1950)
GRB_DEC:         -17.7595d {-17d 45' 34.1"} (J2000),
                 -17.7085d {-17d 42' 30.5"} (current),
                 -17.9707d {-17d 58' 14.5"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16921.00 SOD {04:42:01.00} UT,   124.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       336.81d {+22h 27m 15s}   -9.69d {-09d 41' 09"}
SUN_DIST:         62.69 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.06d {+23h 56m 14s}   +4.63d {+04d 38' 00"}
MOON_DIST:        47.10 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      198.95,-62.48 [deg] galactic lon,lat of the burst
ECL_COORDS:       32.10,-31.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #12980
C. J. Saxton (UCL-MSSL), J. R. Cummings (NASA/UMBC), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (NASA/GSFC/ORAU), O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), S. R. Oates (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team:
At 04:39:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120224A (trigger=515976). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 40.975, -17.793 which is
```
   RA(J2000) = 02h 43m 54s
   Dec(J2000) = -17d 47' 32"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 04:41:45.6 UT, 109.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 40.94380, -17.75959 which is equivalent to:
```
   RA(J2000)  = 02h 43m 46.51s
   Dec(J2000) = -17d 45' 34.5"
```
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 160 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.45 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 3.6 (+4.34/-3.51) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 114 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 none of the XRT error circle. 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 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is C. J. Saxton (cjs2 AT mssl.ucl.ac.uk). 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:     Fri 24 Feb 12 04:51:37 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
POINT_ROLL:      268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17069.23 SOD {04:44:29.23} UT,   272.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.742
N_STARS:         17
X_OFFSET:        404 [pixels]
Y_OFFSET:        207 [pixels]
X_MAX:           1843 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00515976000msufc0272.fits
SUN_POSTN:       336.82d {+22h 27m 16s}   -9.68d {-09d 41' 05"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.10d {+23h 56m 23s}   +4.65d {+04d 38' 56"}
MOON_DIST:        47.14 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:51:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
POINT_ROLL:      268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17069.23 SOD {04:44:29.23} UT,   272.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.742
N_STARS:         17
X_OFFSET:        404 [pixels]
Y_OFFSET:        207 [pixels]
X_MAX:           1843 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00515976000msufc0272.fits
SUN_POSTN:       336.82d {+22h 27m 16s}   -9.68d {-09d 41' 04"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.10d {+23h 56m 23s}   +4.65d {+04d 38' 57"}
MOON_DIST:        47.14 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 04:52:39 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     515976,   Seg_Num: 0
GRB_RA:           40.9423d {+02h 43m 46.15s} (J2000),
                  41.0837d {+02h 44m 20.09s} (current),
                  40.3602d {+02h 41m 26.45s} (1950)
GRB_DEC:         -17.7610d {-17d 45' 39.5"} (J2000),
                 -17.7100d {-17d 42' 35.8"} (current),
                 -17.9722d {-17d 58' 20.0"} (1950)
GRB_ERROR:       2.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  16921.00 SOD {04:42:01.00} UT,   124.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       336.82d {+22h 27m 16s}   -9.68d {-09d 41' 04"}
SUN_DIST:         62.69 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.10d {+23h 56m 25s}   +4.65d {+04d 39' 07"}
MOON_DIST:        47.07 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      198.95,-62.48 [deg] galactic lon,lat of the burst
ECL_COORDS:       32.10,-31.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:53:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
ROLL:            268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17069.23 SOD {04:44:29.23} UT,   272.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     351751477
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0280.fits
SUN_POSTN:       336.82d {+22h 27m 16s}   -9.68d {-09d 41' 03"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.11d {+23h 56m 26s}   +4.65d {+04d 39' 13"}
MOON_DIST:        47.13 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 04:53:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
ROLL:            268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17069.23 SOD {04:44:29.23} UT,   272.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     351751477
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0280.fits
SUN_POSTN:       336.82d {+22h 27m 16s}   -9.68d {-09d 41' 03"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.11d {+23h 56m 26s}   +4.65d {+04d 39' 15"}
MOON_DIST:        47.13 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:58:24 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
POINT_ROLL:      268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17673.68 SOD {04:54:33.68} UT,   877.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.794
N_STARS:         37
X_OFFSET:        404 [pixels]
Y_OFFSET:        207 [pixels]
X_MAX:           1843 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00515976000msufc0877.fits
SUN_POSTN:       336.82d {+22h 27m 17s}   -9.68d {-09d 40' 58"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.15d {+23h 56m 36s}   +4.67d {+04d 40' 12"}
MOON_DIST:        47.10 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Feb 12 04:58:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
POINT_ROLL:      268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17673.68 SOD {04:54:33.68} UT,   877.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.794
N_STARS:         37
X_OFFSET:        404 [pixels]
Y_OFFSET:        207 [pixels]
X_MAX:           1843 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00515976000msufc0877.fits
SUN_POSTN:       336.82d {+22h 27m 17s}   -9.68d {-09d 40' 58"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.15d {+23h 56m 36s}   +4.67d {+04d 40' 15"}
MOON_DIST:        47.10 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 04:59:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
ROLL:            268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17673.68 SOD {04:54:33.68} UT,   877.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     351752081
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0885.fits
SUN_POSTN:       336.82d {+22h 27m 17s}   -9.68d {-09d 40' 57"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.16d {+23h 56m 39s}   +4.67d {+04d 40' 28"}
MOON_DIST:        47.09 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:     Fri 24 Feb 12 05:00:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     515976,   Seg_Num: 0
POINT_RA:         41.004d {+02h 44m 01s} (J2000)
POINT_DEC:       -17.790d {-17d 47' 22"} (J2000)
ROLL:            268.111d
IMG_START_DATE:  15981 TJD;    55 DOY;   12/02/24
IMG_START_TIME:  17673.68 SOD {04:54:33.68} UT,   877.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     351752081
X_OFFSET:        963 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1123
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00515976000msuni0885.fits
SUN_POSTN:       336.82d {+22h 27m 17s}   -9.68d {-09d 40' 57"}
SUN_DIST:         62.74 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      359.16d {+23h 56m 39s}   +4.68d {+04d 40' 31"}
MOON_DIST:        47.09 [deg]
MOON_ILLUM:      5 [%]
GAL_COORDS:      199.06,-62.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       32.15,-31.93 [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:        All 4 attachments are included.

GCN Circular #12981
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1421 s of XRT Photon Counting mode data and 2 UVOT images for GRB 120224A, 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 = 40.94221, -17.76130 which is equivalent to:
```
RA (J2000): 02h 43m 46.13s
Dec (J2000): -17d 45' 40.7"
```
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) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #12982
J. Japelj, D. Kopac (U. Ljubljana) and C. Guidorzi (U. Ferrara) report on behalf of a larger collaboration:
The 2-m Faulkes Telescope North automatically began observing GRB 120224A (Saxton et al., GCN 12980), starting at 04:44:40 UT on 2012 February 24. We do not detect any optical counterpart inside the enhanced Swift-XRT error circle (Osborne et al., GCN 12981) down to the following limiting magnitudes:
```
Mid time from   Exp    Filter   Mag limit
trigger (min)   (sec)
-------------------------------------------
44.5            600    R        > 19.3
39.3            480    i'       > 18.6
-------------------------------------------
```
The magnitudes are calibrated against nearby USNO-B1.0 stars.
GCN Circular #12983
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), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), C. J. Saxton (UCL-MSSL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+326 sec from the recent telemetry downlink, we report further analysis of BAT GRB 120224A (trigger #515976) (Saxton, et al., GCN Circ. 12980). The BAT ground-calculated position is RA, Dec = 40.937, -17.779 deg, which is
```
   RA(J2000)  =  02h 43m 44.8s 
   Dec(J2000) = -17d 46' 42.6" 
```
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 29%.
The mask-weighted light curve shows two peaks, the first starting at ~T-20 sec, peaking at ~T-6 sec. The second (and stronger peak) starts at ~T-3 sec, peaks at ~T+1 sec, and ends at ~T+13 sec. T90 (15-350 keV) is 8.13 +- 1.99 sec (estimated error including systematics).
The time-averaged spectrum from T-1.08 to T+8.26 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.25 +- 0.36. The fluence in the 15-150 keV band is 2.4 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band is 0.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/515976/BA/
GCN Circular #12984
N. P. M. Kuin (MSSL-UCL) and C. J. Saxton (UCL-MSSL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120224A 115 s after the BAT trigger (Saxton et al., GCN Circ. 12980). No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 12981) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           115          264          147         >20.7
u_FC               273          522          246         >20.5
white              115         1547          392         >21.2
v                  602         1424           97         >19.4
b                  529         1522           97         >20.2
u                  273         1497          304         >20.4
w1                1107         1127           19         >19.6
m2                1254         1448           39         >19.8
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #12986
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU) and C.J. Saxton report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 120224A (Saxton et al. GCN Circ. 12980), from 95 s to 34.0 ks after the BAT trigger. The data comprise 6 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 12981).
The late-time light curve (from T0+5.3 ks) can be modelled with a power-law decay with a decay index of alpha=0.99 (+/-0.11).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.22 (+0.16, -0.15). The best-fitting absorption column is 3.0 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.4 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (6.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.0 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 2.4 x 10^20 cm^-2
Excess significance: 9.3 sigma
Photon index:	     2.22 (+0.16, -0.15)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00515976.
This circular is an official product of the Swift-XRT team.
GCN Circular #12988
J. Elliott (MPE Garching), S. Klose (TLS Tautenburg) and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB120224A (Swift trigger 515976; Saxton et al., GCN #12980) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile).
First observations started at 00:14 UT on 25 February 2012, 19.58 hrs after the GRB trigger. They were perfomed at an average seeing of 1".27 and at an average airmass of 1.4.
After an exposure time of 4.72 min in g'r'i'z' and 8 min JHK, no source was detected.
Second observations started at 00:48 UT on 26 February 2012, 1.84 days after the GRB trigger. They were performed at an average seeing of 0".96 and at an average airmass of 2.0.
We find a single point source within the 1".8 refined Swift-XRT error circle reported by Osborne et al. (GCN #12981) at
RA (J2000.0) = 02:43:46.15 = 40.94230
Dec. (J2000.0) = -17:45:42.0 = -17.76169
with an uncertainty of 0".5 in each coordinate.
Based on total exposures of 36 min in JHK, we estimate preliminary magnitude (AB) of,
J = 20.9 +/- 0.2
The given magnitude is calibrated against 2MASS field stars and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E(B-V)=0.04 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #12990
A.Volnova (SAI MSU), E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 120224A (Saxton et al., GCN 12980) with AZT-33IK telescope of Sayan observatory (Mondy) on Feb. 24 between (UT) 12:49:39 - 13:22:16 (mean time 8.44 hrs after burst trigger) in R filter under mean FWHM of 4.5" and at high airmass of ~ 4 . In a combined image we do not detect the afterglow candidate (Elliott et al., GCN 12988). A photometry is based on the USNO-B1.0 star USNO-B1.0 0722-0043384 (02:43:36.48 -17:47:18.1) assuming R = 18.57:
```
T0+,        Filter,  Exposure,   OT,     UpperLimit (3 sigma)
(mid, d)             (s)

0.3518    R     37 x 60         n/d        20.3
```
GCN Circular #12991
K. Wiersema (Leicester), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), J. P. U. Fynbo (DARK/NBI), N. R. Tanvir (U. Leicester), D. Malesani (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), S. D. Vergani (INAF/OAB), S. Covino (INAF/OAB), H. Flores (Obs. Paris) report on behalf of the X-shooter GTO GRB collaboration:
We observed the position of the afterglow of GRB 120224A (Saxton et al., GCN 12980) using the X-shooter spectrograph mounted on the VLT. Observations started on 00:30 UT on 25 February 2012, i.e. 19.83 hours after burst. In the acquisition images, 5 x 150 seconds in R filter, we find a faint source, consistent with the candidate afterglow reported by Elliott et al (GCN 12988). We find a preliminary magnitude of R=22.3 using the USNO-B star 0722-0043411 (R=16.65). The detection of the afterglow in the R band places a limit on the redshift of approximately z < 5.
We performed spectroscopy of this source, under poor seeing and high airmass. We detect a faint continuum in the near-infrared arm over the whole wavelength range, at low signal to noise. In the visual arm data we detect a very faint continuum at the red end of the wavelength range. No emission lines are detected. Because of the low signal to noise we are not able to identify absorption features. The non- detection of continuum emission below ~600 nm may be indicative of a moderately high redshift for this burst, though alternatives, such as a reddened spectrum (note that the X-ray afterglow shows considerable absorption; Osborne et al. GCN 12986), can not be excluded at present.
We are grateful for the excellent support from the Paranal Observatory staff, in particular Myriam Rodrigues and Ivo Saviane.
arXiv:1505.06743 X-shooter Balmer break redshift: 1.1+-0.2

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Jochen Greiner, last update: 25-Jun-2015 [Disclaimer]