Gamma-ray Burst 091221

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:06 UT
NOTICE_TYPE:     Fermi-GBM Alert
RECORD_NUM:      1
TRIGGER_NUM:     283121579     
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
TRIGGER_SIGNIF:  4.7 [sigma]   
TRIGGER_DUR:     4.096 [sec]   
E_RANGE:         3-4 [chan]   47-291 [keV]
ALGORITHM:       17
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 0,1,0, 0,0,
COMMENTS:        Fermi-GBM Trigger Alert.
COMMENTS:        This trigger occurred at longitude,latitude = 281.75,7.27 [deg].

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:11 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.754d {+03h 43m 01s} (J2000),
                  55.901d {+03h 43m 36s} (current),
                  55.015d {+03h 40m 04s} (1950)
GRB_DEC:         +23.212d {+23d 12' 42"} (J2000),
                 +23.243d {+23d 14' 35"} (current),
                 +23.054d {+23d 03' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4738 [cnts]    Image_Peak=183 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       32240 [cnts]
BKG_TIME:        75154.63 SOD {20:52:34.63} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75172.29 SOD {20:52:52.29} UT
GRB_PHI:         -57.07 [deg]
GRB_THETA:        27.29 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.38 [sigma]
IMAGE_SIGNIF:    7.54 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -2  +0  +0 +85  +0 
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.64 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.62d {+21h 58m 30s}   -8.89d {-08d 53' 19"}
MOON_DIST:        90.12 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.49,-24.80 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       58.79,  3.41 [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 = 81.77,15.03 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:38 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      67
TRIGGER_NUM:     283121579
GRB_RA:           52.750d {+03h 31m 00s} (J2000),
                  52.902d {+03h 31m 37s} (current),
                  51.987d {+03h 27m 57s} (1950)
GRB_DEC:         +29.060d {+29d 03' 36"} (J2000),
                 +29.094d {+29d 05' 37"} (current),
                 +28.890d {+28d 53' 24"} (1950)
GRB_ERROR:       8.71 [deg radius, statistical only]
DATA_SIGNIF:     10.30 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
GRB_PHI:         157.00 [deg]
GRB_THETA:        47.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        146.27 [deg]   Sun_angle= -9.5 [hr] (East of Sun)
MOON_POSTN:      329.63d {+21h 58m 31s}   -8.89d {-08d 53' 13"}
MOON_DIST:        88.51 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      160.15,-22.05 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       57.53,  9.72 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:46 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      70
TRIGGER_NUM:     283121579
GRB_RA:           60.800d {+04h 03m 12s} (J2000),
                  60.946d {+04h 03m 47s} (current),
                  60.069d {+04h 00m 17s} (1950)
GRB_DEC:         +20.510d {+20d 30' 36"} (J2000),
                 +20.537d {+20d 32' 13"} (current),
                 +20.373d {+20d 22' 21"} (1950)
GRB_ERROR:       2.99 [deg radius, statistical only]
DATA_SIGNIF:     26.80 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
GRB_PHI:         156.00 [deg]
GRB_THETA:        58.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        152.82 [deg]   Sun_angle= -10.1 [hr] (East of Sun)
MOON_POSTN:      329.63d {+21h 58m 31s}   -8.89d {-08d 53' 12"}
MOON_DIST:        94.33 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      172.24,-23.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       62.81, -0.22 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:27 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     283121579
GRB_RA:           51.483d {+03h 25m 56s} (J2000),
                  51.630d {+03h 26m 31s} (current),
                  50.747d {+03h 22m 59s} (1950)
GRB_DEC:         +23.867d {+23d 51' 60"} (J2000),
                 +23.901d {+23d 54' 04"} (current),
                 +23.692d {+23d 41' 31"} (1950)
GRB_ERROR:       22.40 [deg radius, statistical plus systematic]
GRB_INTEN:       62 [cnts/sec]
DATA_SIGNIF:     5.10 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
GRB_PHI:         151.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.07
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      94%  GRB
2nd_MOST_LIKELY:   2%  Distant Particles
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 0,1,0, 0,0,
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        144.84 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      329.63d {+21h 58m 30s}   -8.89d {-08d 53' 16"}
MOON_DIST:        86.39 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      162.70,-26.83 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       55.14,  4.97 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 281.75,7.27 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:55:03 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.7998d {+03h 43m 11.9s} (J2000),
                  55.9473d {+03h 43m 47.3s} (current),
                  55.0612d {+03h 40m 14.6s} (1950)
GRB_DEC:         +23.2406d {+23d 14' 26.1"} (J2000),
                 +23.2717d {+23d 16' 18.2"} (current),
                 +23.0826d {+23d 04' 57.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       53 [cnts]
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75244.67 SOD {20:54:04.67} UT,   72.4 [sec] since BAT Trigger Time
CENTROID_X:      344.20,  raw= 344  [pixels]
CENTROID_Y:      268.73,  raw= 269  [pixels]
ROLL:            262.61 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -68.99
GRB_POS_XRT_Z:   98.77
IMAGE_URL:       sw00380311000msxps_rw.img
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.68 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.64d {+21h 58m 33s}   -8.88d {-08d 52' 56"}
MOON_DIST:        90.15 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.51,-24.75 [deg] galactic lon,lat of the burst
ECL_COORDS:       58.84,  3.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:54:43 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.7998d {+03h 43m 11.95s} (J2000),
                  55.9473d {+03h 43m 47.35s} (current),
                  55.0612d {+03h 40m 14.68s} (1950)
GRB_DEC:         +23.2406d {+23d 14' 26.1"} (J2000),
                 +23.2717d {+23d 16' 18.2"} (current),
                 +23.0826d {+23d 04' 57.4"} (1950)
GRB_ERROR:       5.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.47e-09 [erg/cm2/sec]
GRB_SIGNIF:      7.28 [sigma]
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75244.67 SOD {20:54:04.67} UT,   72.4 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.21 261.38 243.62
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.68 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.64d {+21h 58m 33s}   -8.88d {-08d 53' 00"}
MOON_DIST:        90.15 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.51,-24.75 [deg] galactic lon,lat of the burst
ECL_COORDS:       58.84,  3.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 3.07 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:54:56 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.7998d {+03h 43m 11.9s} (J2000),
                  55.9473d {+03h 43m 47.3s} (current),
                  55.0612d {+03h 40m 14.6s} (1950)
GRB_DEC:         +23.2406d {+23d 14' 26.1"} (J2000),
                 +23.2717d {+23d 16' 18.2"} (current),
                 +23.0826d {+23d 04' 57.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       53 [cnts]
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75244.67 SOD {20:54:04.67} UT,   72.4 [sec] since BAT Trigger Time
CENTROID_X:      344.20,  raw= 344  [pixels]
CENTROID_Y:      268.73,  raw= 269  [pixels]
ROLL:            262.61 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -68.99
GRB_POS_XRT_Z:   98.77
IMAGE_URL:       sw00380311000msxps_rw.img
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.68 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.64d {+21h 58m 33s}   -8.88d {-08d 52' 58"}
MOON_DIST:        90.15 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.51,-24.75 [deg] galactic lon,lat of the burst
ECL_COORDS:       58.84,  3.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:36 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      68
TRIGGER_NUM:     283121579
GRB_RA:           39.783d {+02h 39m 08s} (J2000),
                  39.924d {+02h 39m 42s} (current),
                  39.077d {+02h 36m 18s} (1950)
GRB_DEC:         +20.550d {+20d 33' 00"} (J2000),
                 +20.593d {+20d 35' 33"} (current),
                 +20.335d {+20d 20' 06"} (1950)
GRB_ERROR:       7.42 [deg radius, statistical plus systematic]
GRB_INTEN:       249 [cnts/sec]
DATA_SIGNIF:     19.50 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
GRB_PHI:         137.00 [deg]
GRB_THETA:        45.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.82
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      94%  GRB
2nd_MOST_LIKELY:   4%  GRO_J0422_32
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 0,1,0, 0,0,
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        133.59 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      329.63d {+21h 58m 31s}   -8.89d {-08d 53' 14"}
MOON_DIST:        75.08 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      154.39,-35.66 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       43.77,  4.80 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 281.75,7.27 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:53:51 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      71
TRIGGER_NUM:     283121579
GRB_RA:           60.770d {+04h 03m 05s} (J2000),
                  60.917d {+04h 03m 40s} (current),
                  60.033d {+04h 00m 08s} (1950)
GRB_DEC:         +21.760d {+21d 45' 36"} (J2000),
                 +21.787d {+21d 47' 13"} (current),
                 +21.622d {+21d 37' 21"} (1950)
GRB_ERROR:       3.91 [deg radius, statistical only]
DATA_SIGNIF:     25.70 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75177.22 SOD {20:52:57.22} UT
GRB_PHI:         157.00 [deg]
GRB_THETA:        57.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        153.02 [deg]   Sun_angle= -10.1 [hr] (East of Sun)
MOON_POSTN:      329.63d {+21h 58m 31s}   -8.89d {-08d 53' 11"}
MOON_DIST:        94.47 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      171.24,-22.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       63.03,  1.02 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:56:37 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.754d {+03h 43m 01s} (J2000),
                  55.901d {+03h 43m 36s} (current),
                  55.015d {+03h 40m 04s} (1950)
GRB_DEC:         +23.212d {+23d 12' 42"} (J2000),
                 +23.243d {+23d 14' 35"} (current),
                 +23.054d {+23d 03' 13"} (1950)
GRB_DATE:        15186 TJD;   355 DOY;   09/12/21
GRB_TIME:        75172.29 SOD {20:52:52.29} UT
TRIGGER_INDEX:   148
GRB_PHI:         -57.07 [deg]
GRB_THETA:        27.29 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.38 [sigma]
IMAGE_SIGNIF:    7.54 [sigma]
LC_URL:          sw00380311000msb.lc
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.64 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.65d {+21h 58m 36s}   -8.88d {-08d 52' 37"}
MOON_DIST:        90.09 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.49,-24.80 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       58.79,  3.41 [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 = 81.77,15.03 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:57:18 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75251.76 SOD {20:54:11.76} UT,   79.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.417
N_STARS:         45
X_OFFSET:        592 [pixels]
Y_OFFSET:        464 [pixels]
X_MAX:           1551 [pixels]
Y_MAX:           1423 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00380311000msufc0079.fits
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.66d {+21h 58m 37s}   -8.87d {-08d 52' 29"}
MOON_DIST:        90.10 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:58:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75251.76 SOD {20:54:11.76} UT,   79.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.417
N_STARS:         45
X_OFFSET:        592 [pixels]
Y_OFFSET:        464 [pixels]
X_MAX:           1551 [pixels]
Y_MAX:           1423 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00380311000msufc0079.fits
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.66d {+21h 58m 39s}   -8.87d {-08d 52' 20"}
MOON_DIST:        90.09 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [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:     Mon 21 Dec 09 20:58:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
ROLL:            262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75251.76 SOD {20:54:11.76} UT,   79.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     283121657
X_OFFSET:        703 [pixels]
Y_OFFSET:        1089 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       863
Y_GRB_POS:       1249
BINNING_INDEX:   1
IM_URL:          sw00380311000msuni0085.fits
SUN_POSTN:       270.14d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.67d {+21h 58m 40s}   -8.87d {-08d 52' 11"}
MOON_DIST:        90.09 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [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:     Mon 21 Dec 09 20:59:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
ROLL:            262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75251.76 SOD {20:54:11.76} UT,   79.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     283121657
X_OFFSET:        703 [pixels]
Y_OFFSET:        1089 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       863
Y_GRB_POS:       1249
BINNING_INDEX:   1
IM_URL:          sw00380311000msuni0085.fits
SUN_POSTN:       270.14d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.67d {+21h 58m 40s}   -8.87d {-08d 52' 07"}
MOON_DIST:        90.09 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 20:59:44 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     380311,   Seg_Num: 0
GRB_RA:           55.7982d {+03h 43m 11.56s} (J2000),
                  55.9457d {+03h 43m 46.97s} (current),
                  55.0596d {+03h 40m 14.30s} (1950)
GRB_DEC:         +23.2404d {+23d 14' 25.4"} (J2000),
                 +23.2715d {+23d 16' 17.5"} (current),
                 +23.0824d {+23d 04' 56.7"} (1950)
GRB_ERROR:       4.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75348.00 SOD {20:55:48.00} UT,   175.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       270.15d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.68 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.67d {+21h 58m 42s}   -8.87d {-08d 52' 00"}
MOON_DIST:        90.11 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.51,-24.76 [deg] galactic lon,lat of the burst
ECL_COORDS:       58.84,  3.42 [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:     Mon 21 Dec 09 20:57:18 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75251.76 SOD {20:54:11.76} UT,   79.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.417
N_STARS:         45
X_OFFSET:        592 [pixels]
Y_OFFSET:        464 [pixels]
X_MAX:           1551 [pixels]
Y_MAX:           1423 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00380311000msufc0079.fits
SUN_POSTN:       270.14d {+18h 00m 34s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.66d {+21h 58m 37s}   -8.87d {-08d 52' 29"}
MOON_DIST:        90.10 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 21:02:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75463.99 SOD {20:57:43.99} UT,   291.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.008
N_STARS:         9
X_OFFSET:        383 [pixels]
Y_OFFSET:        769 [pixels]
X_MAX:           1342 [pixels]
Y_MAX:           1728 [pixels]
DET_THRESH:      2
PHOTO_THRESH:    2
SL_URL:          sw00380311000msufc0291.fits
SUN_POSTN:       270.15d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.70d {+21h 58m 47s}   -8.86d {-08d 51' 24"}
MOON_DIST:        90.06 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st SrcList Notice.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 21:02:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75463.99 SOD {20:57:43.99} UT,   291.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.008
N_STARS:         9
X_OFFSET:        383 [pixels]
Y_OFFSET:        769 [pixels]
X_MAX:           1342 [pixels]
Y_MAX:           1728 [pixels]
DET_THRESH:      2
PHOTO_THRESH:    2
SL_URL:          sw00380311000msufc0291.fits
SUN_POSTN:       270.15d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.70d {+21h 58m 47s}   -8.86d {-08d 51' 24"}
MOON_DIST:        90.06 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st SrcList Notice.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 21:03:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
POINT_ROLL:      262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75463.99 SOD {20:57:43.99} UT,   291.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.008
N_STARS:         9
X_OFFSET:        383 [pixels]
Y_OFFSET:        769 [pixels]
X_MAX:           1342 [pixels]
Y_MAX:           1728 [pixels]
DET_THRESH:      2
PHOTO_THRESH:    2
SL_URL:          sw00380311000msufc0291.fits
SUN_POSTN:       270.15d {+18h 00m 35s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.70d {+21h 58m 48s}   -8.86d {-08d 51' 18"}
MOON_DIST:        90.05 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 Dec 09 21:04:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
ROLL:            262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75463.99 SOD {20:57:43.99} UT,   291.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     283121869
X_OFFSET:        703 [pixels]
Y_OFFSET:        1089 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       863
Y_GRB_POS:       1249
BINNING_INDEX:   1
IM_URL:          sw00380311000msuni0297.fits
SUN_POSTN:       270.15d {+18h 00m 36s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.71d {+21h 58m 49s}   -8.85d {-08d 51' 07"}
MOON_DIST:        90.05 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st Image Notice.  
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:     Mon 21 Dec 09 21:04:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     380311,   Seg_Num: 0
POINT_RA:         55.772d {+03h 43m 05s} (J2000)
POINT_DEC:       +23.218d {+23d 13' 06"} (J2000)
ROLL:            262.615d
IMG_START_DATE:  15186 TJD;   355 DOY;   09/12/21
IMG_START_TIME:  75463.99 SOD {20:57:43.99} UT,   291.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     283121869
X_OFFSET:        703 [pixels]
Y_OFFSET:        1089 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       863
Y_GRB_POS:       1249
BINNING_INDEX:   1
IM_URL:          sw00380311000msuni0297.fits
SUN_POSTN:       270.15d {+18h 00m 36s}  -23.44d {-23d 26' 14"}
SUN_DIST:        148.65 [deg]   Sun_angle= -9.7 [hr] (East of Sun)
MOON_POSTN:      329.71d {+21h 58m 50s}   -8.85d {-08d 51' 04"}
MOON_DIST:        90.04 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      166.50,-24.79 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       58.81,  3.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #10283
H. A. Krimm (CRESST/GSFC/USRA), D. N. Burrows (PSU), P.A. Curran (MSSL-UCL), A. de Ugarte Postigo (INAF-OAB), N. Gehrels (NASA/GSFC), D. Grupe (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), N. P. M. Kuin (MSSL), J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU), M. C. Stroh (PSU), E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 20:52:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 091221 (trigger=380311). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 55.754, +23.212 which is
```
   RA(J2000) = 03h 43m 01s
   Dec(J2000) = +23d 12' 42"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a peak from T+0 to T+15 seconds with a second, larger peak from T+15 to T+40. There is some complexity in the light curve from A0535+262 (currently in outburst at ~5 Crabs of flux) in the Field Of View, but the GRB peaks are distinguishable from the softer A0535+262 emission. The peak count rate was 3500 counts/sec at ~30 sec after the trigger.
The XRT began observing the field at 20:54:04.7 UT, 72.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 55.79831, 23.24030 which is equivalent to:
```
   RA(J2000)  = 03h 43m 11.59s
   Dec(J2000) = +23d 14' 25.1"
```
with an uncertainty of 4.2 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 170 arcseconds from the BAT position.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.09e+21 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 1.47e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 79 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 19.6 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 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.22. We note the possibility of a faint source on the northern edge of the XRT error circle. Further analysis is forthcoming.
Burst Advocate for this burst is H. A. Krimm (krimm 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 Circular #10284
GRB 091221: ROTSE-III Detection of Optical Counterpart
W. Zheng, F. Yuan and S. B. Pandey (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 091221 (Swift trigger 380311, GCN 10283 Krimm et al.). The first image was at 20:53:18.1 UT, 25.8 s after the burst (9.1 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 17.4 magnitude, source with coordinates:
03:43:11.47 +23:14:29.38 (J2000), with positional uncertainty of 1" or better
```
start UT    	mag     mlim(of image)
----------------------------------
20:54:49.5     17.4     18.0 
```
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/gsb380311_3c011-020_key.jpg, the candidate is marked as 110.
Continuing observations are in progress.
GCN Circular #10285
S. T. Holland (CRESST/GSFC/USRA), M. de Pasquale (MSSL), P. Kuin (MSSL), and H. A. Krimm (CRESST/GSFC/USRA) report on the behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 091221 (Krimm et al. 2009, GCN Circ. 10283) starting approximately 80 s after the BAT detection. We confirm the optical afterglow detected by Krimm et al. 2009, GCN Circ 10283 and Zheng et al. 2009, GCN Circ. 10284. The preliminary UVOT position is
```
     RA =  03:43:11.47 =  55.79771 deg
    Dec = +23:14:28.9  = +23.24136 deg
```
with a preliminary error estimate of 0.6 arcsec (radius, 90% containment). The preliminary white magnitude is
```
Filter     TSTART     TSTOP     EXPOSURE        Mag   Err
---------------------------------------------------------
White          80       230          150      20.22  0.28
---------------------------------------------------------
```
The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.22 mag (Schlegel et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #10286
R. Filgas, P. Afonso (both MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching), report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile), started follow-up observations of GRB 091221 (Krimm et al. 2009, GCN 10283) on Dec 22, at 01:27 UT (4.5 hrs after the burst).
For the suggested GRB afterglow (Zheng et al. 2009, GCN 10284; Holland et al. 2009, GCN 10285), based on a first 8 min exposure, we estimate the following preliminary magnitudes (in the AB system):
```
g' = 22.90 +/- 0.30
r' = 22.27 +/- 0.30
i' = 21.95 +/- 0.30
z' = 22.20 +/- 0.30
J  = 20.16 +/- 0.20
H  > 19.9
K  > 19.1
```
using GROND zeropoints and 2MASS catalog (airmass 1.8). Observations are ongoing.
Taking into account a Galactic reddening of E(B-V)=0.22 mag (Holland et al. 2009, GCN 10285), we estimate a photometric redshift of z<3.5. At present we cannot decide if the z'-band magnitude is indicating to a broad-band absorption feature or if we underestimate the magnitude error in this band (where the source is very faint).
GCN Circular #10287
P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team:
Using 3.7 ks of XRT Photon Counting mode data and 7 UVOT images, 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 = 55.79749, 23.24119 which is equivalent to:
```
RA (J2000):  03 43 11.40
Dec (J2000): +23 14 28.3
```
with an uncertainty of 1.7 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 is an official product of the Swift-XRT team.
GCN Circular #10288
J. Mao (INAF-OAB) and H. A. Krimm (CRESST/GSFC/USRA) report on behalf of=20 the Swift-XRT team:
We have analysed 4.7 ks of XRT data for GRB 091221 (Krimm et al. GCN=20 Circ. 10283), from 78 s to 11.6 ks after the BAT trigger. The data comprise 332 s in Windowed=20 Timing (WT) mode with the remainder in Photon Counting (PC) mode. The UVOT-enhanced XRT position was given=20 in Evans et al. (GCN Circ. 10287).
The light curve shows a flare feature from T0+90 s to T0+200 s, the peak=20 value is about 55 count/s at T0+106 s. After that, the light curve can be modelled with a power-law=20 decay with a decay index of alpha=3D1.07 =B1 0.05.
A spectrum formed from the WT mode data can be fitted with an absorbed=20 power-law with a photon spectral index of 2.52 (+0.16, -0.17). The best-fitting absorption column is 3.6=20 (+/- 0.4) x 1021 cm^-2, in excess of the Galactic value of 1.1 x 1021 cm^-2 (Kalberla et al. 2005).=20 The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor=20 deduced from this spectrum is 4.4 x 10^-11 (7.2 x 10^-11) erg cm^-2 count^-1. The spectrum formed from=20 the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.68 (+0.45,=20 -0.51). The best-fitting absorption column is about 1.1 x 1021 cm^-2, in consistent with the Galactic value.
If the light curve continues to decay with a power-law decay index of=20 1.07, the count rate at T0+24 hours will be 2.3 x 10^-3 count s^-1, corresponding to an observed=20 (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-13 (1.6 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at=20 http://www.swift.ac.uk/xrt_products/00380311.
This circular is an official product of the Swift-XRT team.
GCN Circular #10289
M. De Pasquale (MSSL/UCL) and H. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB091221 80s after the BAT trigger with a 150s finding chart exposure in the White filter.
We detect the optical afterglow in the finding chart exposure. The refined UVOT position is RA = 55.79750, Dec = 23.24119 (J2000), corresponding to
```
             RA = 03h 43m 11.40s,
             Dec = +23d 14m 28.3s (J2000)
```
with an estimated uncertainty of 0.6 arcsec (radius, 90% confidence). This position is consistent with the XRT enhanced position (Evans et al., GCN 10287) and ground-based detections (Zheng et al., GCN 10284; Klose et al., GCN 10286).
The afterglow is not detected anymore in single or summed exposures in all filters. Preliminary magnitudes and 3 sigma upper limits are reported below.
```
Filter    T_start(s) T_stop(s)  Exposure(s)    Mag  Err
-----------------------------------------------------------------------
white        80        230       149.8       20.19 +/- 0.27
white      3657      11605       927.1          >21.62
v          4068       5704       393.2          >19.56
b          3452      11054      1278.4          >21.11
u          4683      10142      1083.4          >20.68
uvw1       4478       6075       354.4          >19.96
uvm2       4273       5909       393.3          >19.79
uvw2       3863       5499       393.3          >20.07
------------------------------------------------------------------------
```
The values quoted above are not corrected for the heavy Galactic extinction corresponding to the reddening of E(B-V) = 0.22 in the direction of the burst (Schlegel et al. 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #10290
M. De Pasquale (MSSL/UCL) reports:
GCN circular 10289 title is wrong. It should be
GRB091221: Swift/UVOT refined analysis
not GRB091208B.
I apologize for any confusion.
GCN Circular #10291
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), 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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 091221 (trigger #380311) (Krimm, et al., GCN Circ.#10283). The BAT ground-calculated position is RA, Dec = 55.798, 23.243 deg which is
```
    RA(J2000)  =  03h 43m 11.6s
    Dec(J2000) = +23d 14' 35.2"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%.
The mask-weighted light curve shows a weak peak from T-45 to T-20 sec and a stronger, slow-rise, complex peak from T-10 to T+42 sec. T90 (15-350 keV) is 68.5 +- 5.5 sec (estimated error including systematics).
The time-averaged spectrum from T-43.6 to T+41.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.59 +- 0.06. The fluence in the 15-150 keV band is 5.7 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+20.70 sec in the 15-150 keV band is 3.0 +- 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/380311/BA/
GCN Circular #10293
Colleen A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi GBM Team:
"At 20:52:57.22 UT on 21 December 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 091221 (trigger 283121579 / 091221870) which also triggered the SWIFT-BAT (Krimm et al. 2009, GCN 10283) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 53 degrees.
The GBM light curve shows/consists of single structured peak with a duration (T90) of about 32 s (8-1000 keV). The time-averaged spectrum from T0-2 s to T0+30 s is adequately fit by a Band function with Epeak = 207 (+22/-17) keV, alpha = -0.69 +/- 0.07, and beta = -2.3 (+0.2/-0.3) (C-Stat 724.6 for 481 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (1.38 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+11.3 s in the 8-1000 keV band is 5.1 +/- 0.4 ph/s/cm^2.
During this burst, A0535+262 (currently in a bright outburst at an intensity of ~3xCrab 12-50 keV) and the Crab rose from Earth occultation, causing a significant rise in the background level. This likely adds additional systematic errors to the results, especially T90.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."

GCN Circular #10294
J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, R. Egger, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report:
Skynet observed the Swift/BAT localization of GRB 091221 (Palmer et al., GCN 10283) with four of the 16" PROMPT telescopes at CTIO beginning 4.3 hours after the trigger in BVRI.
We detect the afterglow (Palmer et al., GCN 10283; Zheng et al., GCN 10284). Stacking only images that increase the limiting magnitude yields:

mean                                                       1-sig. 1-sig.
time                                                       sys.   stat.
since                                          cal.        cal.   cal.
trig. tel.     exp.     fil. magnitude         stars       unc.   unc.
(h)            (# x s)                                     (mag)  (mag)

4.9   PROMPT-5 44 x 80  I    > 21.1 (3 sigma)  143 USNO B1 0.338  0.000
            + 1 x 40
4.9   PROMPT-4 42 x 80  R    21.49 +0.27 -0.22 139 USNO B1 0.362  0.000
4.9   PROMPT-3 41 x 80  B    > 21.5 (3 sigma)  82 USNO B1  0.154  0.000
4.9   PROMPT-1 41 x 80  V    21.41 +0.42 -0.31 27 NOMAD    0.193  0.000
7.3   PROMPT-3 136 x 80 B    > 22.1 (3 sigma)  79 USNO B1  0.153  0.000
7.3   PROMPT-5 134 x 80 I    > 21.8 (3 sigma)  120 USNO B1 0.337  0.000
7.3   PROMPT-4 139 x 80 R    22.44 +0.38 -0.28 112 USNO B1 0.392  0.000
7.4   PROMPT-1 145 x 80 V    > 22.0 (3 sigma)  28 NOMAD    0.112  0.000

GCN Circular #10295
K. Nishimoto, T. Sako, H. Naito, D. Suzuki (Nagoya Univ.) on behalf of the MOA Collaboration, M. Kurita (Nagoya Univ.), Y.Ita (NAOJ) on behalf of the IRSF Collaboration report:
We searched for a NIR afterglow of GRB 091221 (GCN 10283, Krimm et al.) starting from 22:27:49.7 UT on 2009 Dec 21 (95 minutes after the burst) with the SIRIUS on the IRSF 1.4m telescope at SAAO in South Africa. In images of a 150sec exposure with J, H and Ks filters, we did not find any object within the error circle of the Swift XRT source position ( GCN 10287, Evans et al.)
Three sigma upper limits are the followings.
```
J > 19.5
H > 18.4
K > 17.0
```
This photometry was done by using the DoPhot and calibrated against the 2MASS cataloged stars.
GCN Report 263.1
GCN_Report 263.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_263_1.pdf by H.A. Krimm at CRSST/GSFC/USRA titled: "Final Swift Observations of GRB 091221"

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Jochen Greiner, last update: 11-Jan-2010 [Disclaimer]