Gamma-ray Burst 061201

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 15:58:49 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     241840,   Seg_Num: 0
GRB_RA:          331.972d {+22h 07m 53s} (J2000),
                 332.126d {+22h 08m 30s} (current),
                 330.843d {+22h 03m 22s} (1950)
GRB_DEC:         -74.600d {-74d 36' 01"} (J2000),
                 -74.566d {-74d 33' 58"} (current),
                 -74.845d {-74d 50' 41"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       860 [cnts]    Image_Peak=72 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10427     E_range: 50-350 keV
BKG_INTEN:       28101 [cnts]
BKG_TIME:        57502.39 SOD {15:58:22.39} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14070 TJD;   335 DOY;   06/12/01
GRB_TIME:        57516.79 SOD {15:58:36.79} UT
GRB_PHI:         -34.57 [deg]
GRB_THETA:        38.11 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     42.93 [sigma]
IMAGE_SIGNIF:    7.37 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +3 +22  +0  +0 -38  +1 
SUN_POSTN:       247.63d {+16h 30m 32s}  -21.85d {-21d 50' 46"}
SUN_DIST:         67.52 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.59d {+01h 26m 23s}  +12.08d {+12d 04' 42"}
MOON_DIST:        91.87 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.71,-38.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.21,-56.61 [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 = 78.62,-19.27 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 16:00:05 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.079d {+22h 08m 19s} (J2000)
POINT_DEC:       -74.599d {-74d 35' 54"} (J2000)
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57598.11 SOD {15:59:58.11} UT,   81.3 [sec] since BAT Trigger Time
COUNTS:          5    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 01 Dec 06 16:02:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.080d {+22h 08m 19s} (J2000)
POINT_DEC:       -74.599d {-74d 35' 54"} (J2000)
POINT_ROLL:      269.257d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57603.31 SOD {16:00:03.31} UT,   86.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.512
N_STARS:         85
X_OFFSET:        669 [pixels]
Y_OFFSET:        455 [pixels]
X_MAX:           1628 [pixels]
Y_MAX:           1414 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00241840000msufc0086.fits
SUN_POSTN:       247.64d {+16h 30m 33s}  -21.85d {-21d 50' 47"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.62d {+01h 26m 30s}  +12.09d {+12d 05' 34"}
MOON_DIST:        91.87 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.69,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.62 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 16:02:31 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.080d {+22h 08m 19s} (J2000)
POINT_DEC:       -74.599d {-74d 35' 54"} (J2000)
POINT_ROLL:      269.257d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57603.31 SOD {16:00:03.31} UT,   86.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.512
N_STARS:         85
X_OFFSET:        669 [pixels]
Y_OFFSET:        455 [pixels]
X_MAX:           1628 [pixels]
Y_MAX:           1414 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00241840000msufc0086.fits
SUN_POSTN:       247.64d {+16h 30m 33s}  -21.85d {-21d 50' 48"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.63d {+01h 26m 31s}  +12.09d {+12d 05' 41"}
MOON_DIST:        91.87 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.69,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.62 [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 01 Dec 06 16:03:26 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.080d {+22h 08m 19s} (J2000)
POINT_DEC:       -74.599d {-74d 35' 54"} (J2000)
ROLL:            269.257d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57603.31 SOD {16:00:03.31} UT,   86.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     186681604
X_OFFSET:        988 [pixels]
Y_OFFSET:        774 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1148
Y_GRB_POS:       934
BINNING_INDEX:   1
IM_URL:          sw00241840000msuni0086.fits
SUN_POSTN:       247.64d {+16h 30m 33s}  -21.85d {-21d 50' 48"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.64d {+01h 26m 33s}  +12.10d {+12d 05' 56"}
MOON_DIST:        91.87 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.69,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.62 [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 01 Dec 06 16:03:47 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.080d {+22h 08m 19s} (J2000)
POINT_DEC:       -74.599d {-74d 35' 54"} (J2000)
ROLL:            269.257d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57603.31 SOD {16:00:03.31} UT,   86.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     186681604
X_OFFSET:        988 [pixels]
Y_OFFSET:        774 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1148
Y_GRB_POS:       934
BINNING_INDEX:   1
IM_URL:          sw00241840000msuni0086.fits
SUN_POSTN:       247.64d {+16h 30m 33s}  -21.85d {-21d 50' 48"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.64d {+01h 26m 34s}  +12.10d {+12d 06' 01"}
MOON_DIST:        91.88 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.69,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.62 [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 01 Dec 06 16:03:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     241840,   Seg_Num: 0
GRB_RA:          331.972d {+22h 07m 53s} (J2000),
                 332.126d {+22h 08m 30s} (current),
                 330.843d {+22h 03m 22s} (1950)
GRB_DEC:         -74.600d {-74d 36' 01"} (J2000),
                 -74.566d {-74d 33' 58"} (current),
                 -74.845d {-74d 50' 41"} (1950)
GRB_DATE:        14070 TJD;   335 DOY;   06/12/01
GRB_TIME:        57516.82 SOD {15:58:36.82} UT
TRIGGER_INDEX:   10427
GRB_PHI:         -34.57 [deg]
GRB_THETA:        38.11 [deg]
DELTA_TIME:      -1.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     42.93 [sigma]
IMAGE_SIGNIF:    7.37 [sigma]
LC_URL:          sw00241840000msb.lc
SUN_POSTN:       247.64d {+16h 30m 33s}  -21.85d {-21d 50' 48"}
SUN_DIST:         67.52 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.64d {+01h 26m 33s}  +12.10d {+12d 05' 60"}
MOON_DIST:        91.90 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.71,-38.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.21,-56.61 [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 = 78.62,-19.27 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 16:10:07 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.084d {+22h 08m 20s} (J2000)
POINT_DEC:       -74.601d {-74d 36' 02"} (J2000)
POINT_ROLL:      269.253d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57708.51 SOD {16:01:48.51} UT,   191.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.480
N_STARS:         117
X_OFFSET:        669 [pixels]
Y_OFFSET:        455 [pixels]
X_MAX:           1628 [pixels]
Y_MAX:           1414 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00241840000msufc0191.fits
SUN_POSTN:       247.64d {+16h 30m 34s}  -21.85d {-21d 50' 50"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.70d {+01h 26m 48s}  +12.13d {+12d 07' 41"}
MOON_DIST:        91.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.68,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 16:10:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.084d {+22h 08m 20s} (J2000)
POINT_DEC:       -74.601d {-74d 36' 02"} (J2000)
POINT_ROLL:      269.253d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57708.51 SOD {16:01:48.51} UT,   191.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.480
N_STARS:         117
X_OFFSET:        669 [pixels]
Y_OFFSET:        455 [pixels]
X_MAX:           1628 [pixels]
Y_MAX:           1414 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00241840000msufc0191.fits
SUN_POSTN:       247.64d {+16h 30m 34s}  -21.85d {-21d 50' 51"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.70d {+01h 26m 48s}  +12.13d {+12d 07' 46"}
MOON_DIST:        91.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.68,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.63 [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 01 Dec 06 16:11:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.084d {+22h 08m 20s} (J2000)
POINT_DEC:       -74.601d {-74d 36' 02"} (J2000)
ROLL:            269.253d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57708.51 SOD {16:01:48.51} UT,   191.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     186681710
X_OFFSET:        988 [pixels]
Y_OFFSET:        774 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1148
Y_GRB_POS:       934
BINNING_INDEX:   1
IM_URL:          sw00241840000msuni0191.fits
SUN_POSTN:       247.64d {+16h 30m 35s}  -21.85d {-21d 50' 51"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.71d {+01h 26m 51s}  +12.14d {+12d 08' 06"}
MOON_DIST:        91.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.68,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.63 [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 01 Dec 06 16:13:29 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     241840,   Seg_Num: 0
GRB_RA:          332.1336d {+22h 08m 32.0s} (J2000),
                 332.2872d {+22h 09m 08.9s} (current),
                 331.0086d {+22h 04m 02.0s} (1950)
GRB_DEC:         -74.5797d {-74d 34' 46.9"} (J2000),
                 -74.5456d {-74d 32' 44.2"} (current),
                 -74.8245d {-74d 49' 28.3"} (1950)
GRB_ERROR:       3.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.00 [sigma]
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57598.11 SOD {15:59:58.11} UT,   81.3 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.19 261.35 242.66
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       247.65d {+16h 30m 35s}  -21.85d {-21d 50' 52"}
SUN_DIST:         67.56 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.73d {+01h 26m 55s}  +12.14d {+12d 08' 35"}
MOON_DIST:        91.91 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.69,-38.24 [deg] galactic lon,lat of the burst
ECL_COORDS:      295.29,-56.62 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values are not valid.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 01 Dec 06 16:11:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     241840,   Seg_Num: 0
POINT_RA:        332.084d {+22h 08m 20s} (J2000)
POINT_DEC:       -74.601d {-74d 36' 02"} (J2000)
ROLL:            269.253d
IMG_START_DATE:  14070 TJD;   335 DOY;   06/12/01
IMG_START_TIME:  57708.51 SOD {16:01:48.51} UT,   191.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     186681710
X_OFFSET:        988 [pixels]
Y_OFFSET:        774 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1148
Y_GRB_POS:       934
BINNING_INDEX:   1
IM_URL:          sw00241840000msuni0191.fits
SUN_POSTN:       247.64d {+16h 30m 35s}  -21.85d {-21d 50' 51"}
SUN_DIST:         67.54 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
MOON_POSTN:       21.71d {+01h 26m 50s}  +12.13d {+12d 08' 01"}
MOON_DIST:        91.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      315.68,-38.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.25,-56.63 [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 Circular #5880
J. S. Bloom (UC Berkeley) notes:
"We note that this apparent short burst GRB (Swift trigger 241840) was localized to within 10 arcmin of a known cluster of galaxies (J2000 center = 22h09m34s, -74d27.3m, Abell 995; Abell et al. ApJS, 1989). Though no redshift is known for this galaxy cluster and the GRB has not (as of yet) been associated with a member of this cluster, we suggest, tentatively, that GRB 061201 has arisen from what is likely a relatively low redshift (z < 0.3). The XRT position appears consistent with the outskirts of a faint galaxy detected in the DSS."
This message may be cited.
GCN Circular #5881
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), O. Godet (U Leicester), S. T. Holland (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), W. B. Landsman (NASA/GSFC), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), K. M. McLean (LANL/UTD), A. Moretti (INAF-OAB), D. M. Palmer (LANL), S. B. Pandey (UCL-MSSL), A. M. Parsons (GSFC), T. Sakamoto (NASA/ORAU), R. L. C. Starling (U Leicester) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 15:58:36 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 061201 (trigger=241840). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 331.972, -74.600 which is
```
RA(J2000) = 22h 07m 53s 
Dec(J2000) = -74d 36' 01" 
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak with some sub-structure and total duration of about 2 sec. The peak count rate was ~20000 counts/sec (15-350 keV), at ~1 sec after the trigger. This is also a very hard burst with ~8000 counts/sec in the highest energy bin (100-350 keV) and ~1000 counts/sec in the lowest energy bin (15-25 keV).
The XRT began taking data at 15:59:58 UT, 81 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. Down-linked data show a variable source at position:
```
RA(J2000) =  22h 08m 32.07s 
DEC(J2000) = -74d 34' 47.0"
```
with 3.8" of uncertainty (90% confidence). This position lies 170 arcseconds from the BAT position.
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 86 seconds after the BAT trigger. No 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 0.08.
GCN Circular #5882
C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S.D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), F.E. Marshall (NASA/GSFC), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-239 to T+366 sec from the recent telemetry downlink, we report further analysis of BAT GRB 061201 (trigger #241840) (Marshall, et al., GCN Circ. 5881). The BAT ground-calculated position is RA, Dec = 332.079, -74.569 deg which is
```
   RA(J2000)  =  22h 08m 19.0s 
   Dec(J2000) = -74d 34'  6.6" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%.
The mask-weighted lightcurve shows two main peaks separated by ~0.7 sec, the first starting at T+0 sec, and the second ending at T+1.1 sec. A visual scan of the lightcurve (from T+2 to T+300 sec) places an upper limit of 0.01 ph/cm2/sec for any extended emission. T90 (15-350 keV) is 0.8 +- 0.1 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+0.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.81 +- 0.15. The fluence in the 15-150 keV band is 3.3 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.05 sec in the 15-150 keV band is 3.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The burst shows significant hard to soft spectral evolution. A fit to the first peak (T+0.0 to T+0.7) gives a simple power law index of 0.57 +/- 0.15, while a fit to the second peak (T+0.7 to T+0.9) has a power law index of 2.10 +/- 0.35. Similarly, the light curve shows that the emission in the 15-25 keV channel extends to T+1.5 sec, while emission in the 100-350 keV channel lasts only until ~T+0.6 sec.
GCN Circular #5883
S. T. Holland (CRESST/GSFC/USRA) and F. Marshall (GSFC) report on behalf of the Swift team:
UVOT took a finding chart exposure of 98 seconds with the White filter (160-650 nm) filter starting 86 seconds after the BAT trigger. There is a possible faint source in the XRT error circle (Marshall et al. GCN Circ. 5881) at
```
   RA(J2000)  =  22:08:32.21
   DEC(J2000) = -74:34:47.3
```
with a 1-sigma error radius of about 1.0 arc sec. The possible source has a preliminary White magnitude of 20.9 +/- 0.6 and is detected at the 2.5-sigma significance level. No correction has been made for the expected Milky Way extinction corresponding to E(B-V) of 0.08 mag. This possible source is also detected in a 197 s White exposure starting 6202 s after the BAT trigger with a significant of 3.1-sigma and a preliminary White magnitude of 20.9 +/- 0.4. Since the source is not fading, it is unlikely to be the optical afterglow of GRB 061201, but it may be the host galaxy.
GCN Circular #5884
P. D'Avanzo (INAF-OAB & Univ. Insubria), S. Piranomonte (INAF-OAR), G. Chincarini (INAF.OABr & Univ. Milano-Bicocca), & L. Stella (INAF-OAR), on behalf of the MISTICI collaboration, report:
We observed the field of the short GRB061201 (Marshall et al., GCN 5881, Markwardt et al. GCN 5882) with the VLT equipped with the FORS2 camera. Our observations started on Dec 02.014 UT (8.38 hr after the GRB). We took 10 I-band images, for a total exposure of 900 s.
An object is clearly visible in the resulting average of our set of images at the following coordinates (J2000):
```
R.A.=22:08:32.090
Dec.=-74:34:47.08
```
with an uncertainty of 0.2 arcsecs. This position is consistent with the one reported by Holland and Marshall (GCN 5883). We measure I ~ 22.3 based on the zeropoints reported on the ESO web pages. Given the different adopted filter and the large error in the UVOT measurement, it is difficult to assess variability between the two epochs. We note that the object does not seem to be extended.
We also clearly resolve a galaxy 17" NW of the XRT position.
Further analysis is in progress.
We thank the excellent support of the ESO staff, in particular Paola Amico and Chris Lidman.
This message can be cited.
GCN Circular #5885
M. Perri, G. Stratta, M.L. Conciatore (ASDC), D. N. Burrows (PSU) and F. E. Marshall (NASA/GSFC) report on behalf of the Swift XRT team:
We have analysed the first 4 orbits of Swift XRT data on the GRB 061201 (Marshall et al., GCN Circ. 5881). A 2.7 ks photon counting mode image provides a refined XRT position:
```
RA(J2000)  =  22h 08m 32.21s
Dec(J2000) = -74d 34m 47.6"
```
with an uncertainty of 3.6 arcsec (90% containment). This position is 0.8 arcsec away from the first XRT position quoted in Marshall et al. (GCN Circ. 5881), 0.3 arcseconds from the UVOT optical source (Holland et al., GCN Circ. 5883) and 0.7 arcseconds from the object reported by D'Avanzo et al. (GCN Circ. 5884).
The 0.3-10 keV X-ray light curve between 86s and 18.1ks after the trigger can be fit with a broken power-law with an initial decay slope of -0.56+/-0.15, a break at 1835+1178-1139s, and a post-break slope of -1.6+/-0.4.
The X-ray spectrum covering the time period from T+99s to T+729s is well fit by an absorbed power-law with a photon index of 1.5+/-0.2 and column density of (1.2+/-0.6)e21 cm**-2. We note the Galactic column density in the direction of the source is 5.0e20 cm**-2.
Assuming the X-ray emission continues to decline at the same rate, we predict a 0.3-10 keV XRT count rate of 0.002 count/s at T+24hr, which corresponds to an observed 0.3-10 keV flux of 1.1e-13 erg/cm**2/s.
This circular is an official product of the Swift XRT Team.
GCN Report 18.1
GCN_Report 18.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_18_1.pdf by F. Marshall at GSFC titled: "Swift Observations of the Short/Hard Burst GRB 061201"
GCN Circular #5890
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report:
The short hard GRB 061201 (Swift-BAT trigger #241840; Marshall et al., GCN 5881; Markwardt et al., GCN 5882) triggered Konus-Wind at T0=57514.558 s UT (15:58:34.558).
As observed by Konus-Wind it had a duration of ~0.6 s, fluence 5.33(-4.44, +0.70)x10^-6 erg/cm2, the 16-ms peak flux measured from T0+0.528 3.19(-2.72, +0.72)x10^-5 erg/cm2/s (both in the 20 keV - 3 MeV energy range).
The time-integrated spectrum of the GRB (from T0 to T0+8.448 s) is well fitted (in the 20 keV - 3 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha) * exp(-(2-alpha)*E/Ep) with alpha = 0.36(-0.65, +0.40) and Ep = 873(-284, +458) keV (chi2 = 79/67 dof).
All the quoted errors are at the 90% confidence level.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB061201_T57514/
GCN Circular #5895
J. Haislip, A. LaCluyze, D. Reichart, S. Heathcote, P. Ugarte, A. Alvares, R. Baptista, & M. Nysewander report on behalf of the UNC team of the FUN GRB Collaboration:
We observed the localization of the short/hard GRB 061201 (Marshal et al., GCN 5881) with SOAR/OSIRIS in JKs beginning 10.2 hours after the burst.
We detect the source identified by Holland et al. (GCN 5883) and D'Avanzo et al. (GCN 5884).
We reobserved the field in J beginning 33.6 hours after the burst. The source appears to have faded by at least 1.3 mag (3 sigma) and is no longer detected.
Consequently, this source appears to be the afterglow.
GCN Circular #5896
P. D'Avanzo (INAF-OABr & Univ. Insubria) and S. Piranomonte (INAF-OAR) report on behalf of the MISTICI collaboration:
We continued monitoring the afterglow of the short GRB061201 (Marshall et al., GCN 5881) with the VLT equipped with the FORS2 camera. Observations were carried out in the I filter. From a comparison with a set of nearby field stars we conclude that the object detected in our previous images (D'Avanzo et al. GCN 5884; see also Holland et al. GCN 5883) faded in the I-band by about 1.8 mag between Dec 2.025 UT and Dec 3.045 UT (0.359 and 1.379 days after the burst, respectively). The inferred decay index is thus ~ 1.2.
We note a discrepancy of about 0.7 mag in the absolute calibration during the two nights, based on observations of Landolt standard fields. We thus warn that the absolute calibration is still preliminary. The decay slope is however independent of this and thus robust.
We thus fully confirm that the object proposed by Holland et al. (GCN 5883) and D'Avanzo et al. (GCN 5884), as already found by Haislip et al. (GCN 5895).
We thank the support of the ESO staff.
This message can be cited.
GCN Circular #5898
S. T. Holland (CRESST/GSFC/USRA) and F. E. Marshall (NASA/GSFC) report on behalf of the Swift team:
UVOT observed the field of GRB 061201 during the first 19972 s after the BAT trigger (Marshall et al., GCN Circ. 5881). We detect the source seen by D'Avanzo (2006, GCN Circ. 5884) at the 4.2-sigma level in the White filter (160-650 nm) and at the 4.5-sigma level in a coadded image of all the UV filters. The coordinates of the source in the White image are:
```
   RA(J2000)  =  22:08:32.06
   DEC(J2000) = -74:34:47.9
```
with a 1-sigma error radius of about 0.5 arcsec, consistent with the VLT source.
Our magnitudes and 3-sigma upper limits for all the UVOT filters are:
```
Filter    Start     Stop   Exposure     Mag  Err Significance
   V         191   12,136     1118      20.8  3-sigma upper limit
   B         669     6197      206      20.9  3-sigma upper limit
   U         645     5992      216      20.7  0.4    2.6
  UVW1       621   17,926      519      20.7  0.5    2.9
          21,392   58,442   11,555      22.9  0.5    2.5
          86,427  160,471   19,972      23.0  3-sigma upper limit
  UVM2      5384   15,948      676      20.5  0.5    2.7
  UVW2       697     6512      122      19.8  0.5    2.5
White         86     6402      304      20.8  0.3    4.2
Comb. UV     621   17,926     1337      20.8  0.4    4.5
```
The magnitude in the combined UV exposure (coadded UVW1, UVM2, and UVW2) between 621 sand 17,926 s is 20.8 +/- 0.4, assuming that the source has equal magnitude in each of these filters.
Since the source is detected in the UVW2 filter, we estimate an upper limit to the redshift of about 1.7.
GCN Circular #5909
P. D'Avanzo (INAF-OABr & Univ. Insubria) and S. Piranomonte (INAF-OAR) report on behalf of the MISTICI collaboration:
A careful inspection and re-analysis of our VLT I-band images of the short GRB061201 (D'Avanzo & Piranomonte, GCN 5896) reveals that in our second epoch of observations (carried out 1.379 days after the burst) no object is clearly visible at the position of the optical counterpart (Holland et al. GCN 5883, Haislip et al. GCN 5895, D'Avanzo et al. GCN 5884) down to I > 23.6 mag (3sigma confidence level).
So, with respect to our first epoch of observation (D'Avanzo et al. GCN 5884) the afterglow clearly faded, but we can only constrain the decay index to be > 0.8. This message can be cited.
GCN Circular #5944
S. Blondin, G. Narayan (Harvard/CfA), J. S. Bloom (UC Berkeley), H- W. Chen (U Chicago), R. P. Kirshner, P. Challis, M. Hicken, M. Modjaz, A. Friedman, M. Wood-Vasey (Harvard/CfA), and J. X. Prochaska (UC Santa Cruz) report on behalf of a larger collaboration:
"The final X-ray afterglow position (Perri et al. 2006; GCN 5885) of the short-hard GRB 061201 (Marshall et al. 2006; GCN 5881) lies 8.5 arcmin from the center of the rich Abell cluster 995 (Bloom 2006; GCN 5880). On 13 December 2006 UT, we obtained several spectra of bright apparent cluster members with the LDSS-3 instrument mounted on the Magellan Clay 6.5m Telescope in Chile. We find the following redshifts based upon a preliminary inspection of the spectra:
```
    				     RA (J2000)          DEC(J2000)
				===========================
      object A: z=0.239      22:08:32.1              -74:34:47
      object B: z=0.235      22:09:37.1              -74:26:39
      object D: z=0.238      22:09:05.3              -74:29:29
```
Based on this, we claim a redshift of z=~0.237 for Abell 995 and note that while the GRB is not yet definitively associated with a cluster member galaxy, this redshift (and hence the implied energetics of the event) are very similar to the putative redshifts of short-hard GRBs 050509b (z=0.225), 050724 (z=0.258), and 060502b (z=0.287)."
This message may be cited.
GCN Circular #5945
J. S. Bloom (UC Berkeley) notes:
"The coordinates for one of the galaxies observed in the Abell cluster 995 was given incorrectly in GCN 5944. The correct coordinates are:
object A: z=0.239 22:09:51.9 -74:31:11
We thank Paolo D'Avanzo for pointing out the error."
This message may be cited.
GCN Circular #5952
E. Berger (Carnegie) reports:
"Starting on 2006 Dec. 21.07 UT we used LDSS3 on Magellan to obtain an 1800 sec spectrum of the galaxy located 17 arcsec NW of the optical afterglow of the short GRB 061201 (see also GCN #5884). This is the nearest bright galaxy (R~19 mag) to the GRB position. We detect several emission lines, which we identify as H-beta, [OIII], H-alpha, [NII], and [SII] at a redshift of z=0.111. At this redshift the projected offset of the burst is about 34 kpc, significantly smaller than about 1.9 Mpc relative to the center of Abell 995 (GCN #5944)."
GCN Circular #5995
E. Berger (Carnegie Observatories) reports:
"On December 21.06 UT we used LDSS3 on the Magellan/Clay 6.5-m telescope to obtain spectra of nine apparent members of the galaxy cluster Abell 995 located 8.5 arcmin away from the position of the short GRB 061201 (GCN 5880). Three of these galaxies have been previously observed by Blondin et al. leading to a proposed redshift of z~0.237 for the cluster (GCN 5944). Based on our spectra, which cover the range of about 4000-9500A, we find instead the following redshifts for the nine cluster members:
```
Redshift	RA		Dec
--------------------------------------------
z=0.0866   	22:09:43.735    -74:26:28.92
z=0.0877   	22:09:37.067    -74:26:39.84	*(object B)
z=0.0873   	22:09:05.248    -74:29:29.55	*(object D)
z=0.0849   	22:09:51.790    -74:31:11.06	*(object A)
z=0.0843   	22:08:34.675    -74:26:20.81
z=0.0864   	22:09:40.015    -74:26:53.18
z=0.0866   	22:09:48.052    -74:28:26.22
z=0.0876   	22:09:25.530    -74:29:50.85
z=0.0872   	22:09:32.120    -74:27:35.99
```
These redshifts are based on absorption features corresponding to CaII H&K, G-band, Mg b, E-band, and Na D, as well as H-alpha emission in four of the nine objects. We therefore conclude that the redshift of Abell 995 is z=0.0835. The previously claimed redshift of z~0.237 is likely based on a mis-identification of the Na D feature at lambda_rest ~ 5893A as Mg b at lambda_rest ~ 5174A.
At the correct redshift of the cluster, the projected offset of GRB 061201 is about 0.8 Mpc from the center of the cluster. To cover this distance over a period of about 10 Gyr, the kick velocity would have to be >80 km/sec.
Finally, we re-iterate the presence of a z=0.111 galaxy about 17 arcsec from the optical position of GRB 061201, corresponding to a significantly smaller offset of about 34 kpc (GCN 5952)."
*Objects A,B,D refer to the designation in GCN 5944
1004.2042 from 14 Apr 10
R. Salvaterra et al.: On the offset of Short Gamma-ray Bursts
Short Gamma-Ray Bursts (SGRBs) are expected to form from the coalescence of compact binaries, either of primordial origin or from dynamical interactions in globular clusters. In this paper, we investigate the possibility that the offset and afterglow brightness of a SGRB can help revealing the origin of its progenitor binary. We find that a SGRB is likely to result from the primordial channel if it is observed within 10 kpc from the center of a massive galaxy and shows a detectable afterglow. The same conclusion holds if it is 100 kpc away from a small, isolated galaxy and shows a weak afterglow. On the other hand, a dynamical origin is suggested for those SGRBs with observable afterglow either at a large separation from a massive, isolated galaxy or with an offset of 10-100 kpc from a small, isolated galaxy. We discuss the possibility that SGRBs from the dynamical channel are hosted in intra-cluster globular clusters and find that GRB 061201 may fall within this scenario.
1603.07869 from 28 Mar 16
Zhi-Ping Jin et al.: The 050709 macronova and the GRB/macronova connection
We reanalyzed the publicly-available optical/near-infrared afterglow observations of GRB 050709, the first short GRB from which an optical afterglow was detected. The $I$-band/F814W-band light curve is significantly shallower than the $R$-band light curve. This additional low-luminosity soft component can be a signature of a Li-Paczy\'{n}ski macronova (also known as kilonova) arising from $\sim 0.05~M_\odot$ r-process material launched by a compact binary merger. As macronovae are relatively weak and soft they can be identified only within the afterglows of relatively nearby ($z<0.4$) bursts that have sufficient near-infrared/optical data. There are five such events: GRBs 050709, 060505, 060614, 061201 and 130603B. However, the redshift of 061201 is unclear and there is doubt concerning the origin of GRB 060505. Remarkably, evidence for a macronova signature is found in the afterglow of each one of the remaining three events. This demonstrates that macronovae are ubiquitous. The significant mass ejection supports the suggestion that these events are significant and possible main sites of heavy r-process nucleosynthesis. The identification of two of the three macronova candidates in the $I$-band implies a more promising detection prospect for the ground-based survey.

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Jochen Greiner, last update: 28-Mar-2016 [Disclaimer]