Gamma-ray Burst 060204C

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE


TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:34:58 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     180274,   Seg_Num: 0
GRB_RA:           92.727d {+06h 10m 54s} (J2000),
                  92.899d {+06h 11m 36s} (current),
                  91.314d {+06h 05m 15s} (1950)
GRB_DEC:         +70.171d {+70d 10' 14"} (J2000),
                 +70.169d {+70d 10' 08"} (current),
                 +70.180d {+70d 10' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1091 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        -0.99 SOD {00:00:00.-98} UT
BKG_DUR:         0 [sec]
GRB_DATE:        13770 TJD;    35 DOY;   06/02/04
GRB_TIME:        74023.00 SOD {20:33:43.00} UT
GRB_PHI:         -169.44 [deg]
GRB_THETA:        46.88 [deg]
SOLN_STATUS:     0x413
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.15 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -3  +0  +0 +48  +1 
SUN_POSTN:       318.35d {+21h 13m 25s}  -16.07d {-16d 04' 19"}
SUN_DIST:        119.28 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.40d {+02h 29m 35s}  +17.77d {+17d 46' 25"}
MOON_DIST:        61.96 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.05, 22.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       91.35, 46.74 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 58.31,11.64 [deg].  
COMMENTS:        This trigger occured while the StarTracker had lost lock, so it is probably bogus.

red DSS finding chart ps-file

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:36:26 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.687d {+06h 10m 45s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 36"} (J2000)
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74179.71 SOD {20:36:19.71} UT,   156.7 [sec] since BAT Trigger Time
COUNTS:          7    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:     Sat 04 Feb 06 20:38:02 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     180274,   Seg_Num: 0
GRB_RA:           92.727d {+06h 10m 54s} (J2000),
                  92.899d {+06h 11m 36s} (current),
                  91.314d {+06h 05m 15s} (1950)
GRB_DEC:         +70.171d {+70d 10' 14"} (J2000),
                 +70.169d {+70d 10' 08"} (current),
                 +70.180d {+70d 10' 49"} (1950)
GRB_DATE:        13770 TJD;    35 DOY;   06/02/04
GRB_TIME:        74023.00 SOD {20:33:43.00} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -169.44 [deg]
GRB_THETA:        46.88 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
LC_URL:          sw00180274000msb.lc
SUN_POSTN:       318.35d {+21h 13m 25s}  -16.07d {-16d 04' 16"}
SUN_DIST:        119.28 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.43d {+02h 29m 42s}  +17.78d {+17d 47' 05"}
MOON_DIST:        61.94 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.05, 22.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       91.35, 46.74 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is an image trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 58.31,11.64 [deg].  
COMMENTS:        This trigger occured while the StarTracker had lost lock, so it is probably bogus.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:40:07 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.688d {+06h 10m 45s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 36"} (J2000)
POINT_ROLL:      308.020d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74178.68 SOD {20:36:18.68} UT,   155.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        0.763
N_STARS:         65
X_OFFSET:        399 [pixels]
Y_OFFSET:        614 [pixels]
X_MAX:           1358 [pixels]
Y_MAX:           1573 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00180274000msufc0155.fits
SUN_POSTN:       318.36d {+21h 13m 25s}  -16.07d {-16d 04' 15"}
SUN_DIST:        119.27 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.44d {+02h 29m 47s}  +17.79d {+17d 47' 33"}
MOON_DIST:        61.92 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:40:35 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.688d {+06h 10m 45s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 36"} (J2000)
ROLL:            308.020d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74178.68 SOD {20:36:18.68} UT,   155.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     160778179
X_OFFSET:        719 [pixels]
Y_OFFSET:        934 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       879
Y_GRB_POS:       1094
BINNING_INDEX:   1
IM_URL:          sw00180274000msuni0155.fits
SUN_POSTN:       318.36d {+21h 13m 26s}  -16.07d {-16d 04' 14"}
SUN_DIST:        119.27 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.45d {+02h 29m 48s}  +17.79d {+17d 47' 39"}
MOON_DIST:        61.91 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [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:     Sat 04 Feb 06 20:41:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.688d {+06h 10m 45s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 36"} (J2000)
ROLL:            308.020d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74178.68 SOD {20:36:18.68} UT,   155.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     160778179
X_OFFSET:        719 [pixels]
Y_OFFSET:        934 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       879
Y_GRB_POS:       1094
BINNING_INDEX:   1
IM_URL:          sw00180274000msuni0155.fits
SUN_POSTN:       318.36d {+21h 13m 26s}  -16.07d {-16d 04' 14"}
SUN_DIST:        119.27 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.45d {+02h 29m 49s}  +17.80d {+17d 47' 48"}
MOON_DIST:        61.91 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:42:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.688d {+06h 10m 45s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 36"} (J2000)
POINT_ROLL:      308.020d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74178.68 SOD {20:36:18.68} UT,   155.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        0.763
N_STARS:         65
X_OFFSET:        399 [pixels]
Y_OFFSET:        614 [pixels]
X_MAX:           1358 [pixels]
Y_MAX:           1573 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00180274000msufc0155.fits
SUN_POSTN:       318.36d {+21h 13m 26s}  -16.07d {-16d 04' 13"}
SUN_DIST:        119.26 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.46d {+02h 29m 51s}  +17.80d {+17d 47' 59"}
MOON_DIST:        61.90 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [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:     Sat 04 Feb 06 20:45:44 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.692d {+06h 10m 46s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 38"} (J2000)
POINT_ROLL:      308.025d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74385.56 SOD {20:39:45.56} UT,   362.6 [sec] since BAT Trigger Time
FILTER:          9, B
BKG_MEAN:        1.171
N_STARS:         79
X_OFFSET:        399 [pixels]
Y_OFFSET:        614 [pixels]
X_MAX:           1358 [pixels]
Y_MAX:           1573 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00180274000msufc0362.fits
SUN_POSTN:       318.36d {+21h 13m 26s}  -16.07d {-16d 04' 10"}
SUN_DIST:        119.26 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.49d {+02h 29m 59s}  +17.81d {+17d 48' 46"}
MOON_DIST:        61.88 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 04 Feb 06 20:46:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.692d {+06h 10m 46s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 38"} (J2000)
POINT_ROLL:      308.025d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74385.56 SOD {20:39:45.56} UT,   362.6 [sec] since BAT Trigger Time
FILTER:          9, B
BKG_MEAN:        1.171
N_STARS:         79
X_OFFSET:        399 [pixels]
Y_OFFSET:        614 [pixels]
X_MAX:           1358 [pixels]
Y_MAX:           1573 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00180274000msufc0362.fits
SUN_POSTN:       318.36d {+21h 13m 27s}  -16.07d {-16d 04' 10"}
SUN_DIST:        119.26 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.50d {+02h 30m 01s}  +17.82d {+17d 48' 60"}
MOON_DIST:        61.88 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [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:     Sat 04 Feb 06 20:47:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.692d {+06h 10m 46s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 38"} (J2000)
ROLL:            308.025d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74385.56 SOD {20:39:45.56} UT,   362.6 [sec] since BAT Trigger Time
FILTER:          9, B
EXPOSURE_ID:     160778386
X_OFFSET:        719 [pixels]
Y_OFFSET:        934 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       879
Y_GRB_POS:       1094
BINNING_INDEX:   1
IM_URL:          sw00180274000msuni0362.fits
SUN_POSTN:       318.36d {+21h 13m 27s}  -16.07d {-16d 04' 09"}
SUN_DIST:        119.26 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.51d {+02h 30m 02s}  +17.82d {+17d 49' 05"}
MOON_DIST:        61.87 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [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:     Sat 04 Feb 06 20:48:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     180274,   Seg_Num: 0
POINT_RA:         92.692d {+06h 10m 46s} (J2000)
POINT_DEC:       +70.177d {+70d 10' 38"} (J2000)
ROLL:            308.025d
IMG_START_DATE:  13770 TJD;    35 DOY;   06/02/04
IMG_START_TIME:  74385.56 SOD {20:39:45.56} UT,   362.6 [sec] since BAT Trigger Time
FILTER:          9, B
EXPOSURE_ID:     160778386
X_OFFSET:        719 [pixels]
Y_OFFSET:        934 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       879
Y_GRB_POS:       1094
BINNING_INDEX:   1
IM_URL:          sw00180274000msuni0362.fits
SUN_POSTN:       318.36d {+21h 13m 27s}  -16.07d {-16d 04' 08"}
SUN_DIST:        119.26 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:       37.52d {+02h 30m 05s}  +17.82d {+17d 49' 23"}
MOON_DIST:        61.87 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      144.04, 22.07 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       91.33, 46.75 [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 #4663
D. Grupe (PSU), S. Barthelmy (GSFC), D. Burrows (PSU), A. Cucchiara (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), S. Hunsberger (PSU), J. Kennea (PSU), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Morris (PSU), D. Palmer (LANL), T. Sakamoto (GSFC) on behalf of the Swift team:
At 20:33:43 UT, Swift-BAT triggered and located GRB 060204C (trigger=180274). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 92.727d,+70.171d {06h 10m 54s,+70d 10' 14"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). This is a 64-sec image trigger, and as such, there is little that can be determined from the TDRSS lightcurve.
The S/C slewed immediately and the XRT began taking data at 20:36:19 UT, 157 sec after the BAT trigger. The XRT on-board centroid algorithm did not converge and no prompt position is available, however, the XRT lightcurve suggests the possibility of a decaying source in the field of view. We are waiting for down-linked data to determine the presence of the source.
UVOT took a finding chart exposure of nominal 200 seconds with the V filter starting 156 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction of about 0.6 magnitudes. No afterglow candiate was found in a second B finding chart taken at T+363 sec.
Given that the star tracker had been out-of-lock for only 2 minutes prior to this trigger, it is very unlikely there is a problem with the attitude of this position solution, so we believe this location to be valid.
GCN Circular #4664
E.S. Rykoff (U Mich), S.A. Yost (U Mich), B. E. Schaefer (Louisiana State), F. Yuan (U Mich), T. Guver (U Istanbul), report on behalf of the ROTSE collaboration:
ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, responded to GRB 060204C (Swift trigger 180274, GCN 4663), producing images beginning 6.8 s after the GCN notice time. An automated response took the first image at 20:35:04.8 UT, 81.8 s after the burst, under windy conditions. We took 10 5-sec, 10 20-sec and 31 60-sec eposures. These unfiltered images are calibrated relative to USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma BAT error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.1-17.7; we set the following specific limits.
```
start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
20:35:04.8   20:35:09.8         5     16.1           81.8       N
20:35:04.8   20:37:11.5       126     17.7           81.8       Y
20:37:20.2   20:41:56.3       276     18.2          217.2       Y
```
GCN Circular #4665
A. Melandri, C.G. Mundell, A. Monfardini, A. Gomboc, C. Guidorzi, R.J. Smith, I.A. Steele, C.J. Mottram, D. Bersier, S. Kobayashi, M. Burgdorf, D. Carter and M.F. Bode (Liverpool JMU) report:
"On Feb 04.86 UT the Liverpool Telescope robotically followed up the field of GRB060204C (Swift trigger 180274, Grupe et al, GCN 4663), beginning at 6.42 minutes after the burst event.
The automatic "detection mode" procedure did not detect any obvious afterglow candidate brighter than about R=18.7 mag from 3x10-s images, confirmed by visual inspection.
We note the presence of two bright stars in the field of view that limits our detection capabilities in the surrounding halos.
This message can be cited"
GCN Circular #4666
S. Guziy, S. Vitek, M. Jelinek, A.J. Castro-Tirado, A. de Ugarte Postigo, S.B. Pandey, J. Gorosabel, R. Cuniffe and S.C. Castillo (IAA Granada, Spain), P. Kubanek (ASU Ondrejov, Czech Rep. and ISDC Versoix, Switzerland), M.D. Sabau-Graziati (INTA Madrid, Spain) and R. Hudec (ASU Ondrejov, Czech Rep.), on behalf of larger colaboration
report
The 60cm robotic telescope BOOTES-IR located at Observatorio Sierra Nevada, Southern Spain, observed automatically the position of GRB060204C (Grupe et al. GCN 4663). The telescope slewed automatically within 3m5s after recieving the GCN alert and immediately started the observation. We do not see any optical transient in the GRB errorbox down to the foillowing 3-sigma limits:
```
mean time after GRB   exposure    limit    filter
===================================================
       7m20s            70s       17.8       Rj
       19m5s           270s       18.9       Rj
===================================================
```
Note that BOOTES-IR is still in comissioning phase operating without the IR camera.
This message may be cited.
GCN Circular #4668
Martin Jelinek, D. Martinez, S. Guziy, S. Vitek and A. de Ugarte Postigo (IAA Granada, Spain)
report:
We imaged the error box of Swift GRB060204C (Grupe et al. GCN 4663) with the 1.5m telescope at Observatorio Sierra Nevada. We do not detect any new or variable source within the BAT error box down to the limiting magnitude I=21.0 at an image obtained 38minutes after the GRB. The image is calibrated against USNO-B1.0 I2 magnitude. Further observations are in progress.
This message may be cited.
GCN Circular #4672
D. Grupe, J. A. Kennea, and D. N. Burrows (PSU) report on behalf of the Swift XRT team:
The Swift XRT began observing the field of BAT trigger 180274 (presumed to be GRB 060204C) at 20:36:20 (157 seconds after the BAT trigger). In the first 4 orbits of data (total exposure 8.0 ks) we find no evidence for any source within the BAT error circle.
We place an upper limit of 1e-14 ergs/s/cm2 on any X-ray counterpart to this event.
We do find a fairly bright source 8 arcminutes from the BAT position at (RA, Dec, J2000) = (06:12:23.0, +70 12 42.9), but this object is not fading and appears to be coincident with an object in the DSS (but not in the ROSAT All-sky survey).
We note that it is extremely unusual for the XRT to slew promptly to a long GRB and not find a bright X-ray source in the field of view. In fact, there have been no previous cases in which the XRT slewed to a long GRB field in less than 300 seconds and did not detect an afterglow.
This Circular is an official product of the Swift XRT Team.
GCN Circular #4673
S. Piranomonte (INAF/OARm), D. Malesani (SISSA), H. Navasardyan (INAF/OAPd), N. Masetti (INAF/IASF Bo), report on behalf of a larger collaboration:
We observed the field of GRB 060204C (Grupe et al., GCN 4663) with the Asiago telescope equipped with the AFOSC camera. Ten exposures lasting 3 minutes each were acquired, starting on 2006 Feb 4.9009 UT (mean time Feb 4.9172 UT, i.e. 1.45 hr after the GRB). The seeing was quite bad (~2.4 arcsec).
Visual inspection of the coadded frame reveals no new objects inside the whole BAT error circle, after comparison with the DSS-II. The limiting magnitude of our images is estimated to be R ~ 21.8 (calibrated against the USNO-B1 catalog).
Our images do not cover the position of the XRT source mentioned in GCN 4672 (Grupe et al., GCN 4672), which lies outside the BAT error circle.
This message can be cited.
GCN Circular #4678
M. Andreev (Institute of Astronomy), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 060204C (Grupe et al., GCN 4663) in R-band with the 60 cm telescope of peak Terskol observatory starting Feb. 04 (UT) 20:56. Totally we obtained 27x60 s images in two epochs (UT) 20:56-21:10, and 21:22-21:35. Within whole BAT error circle in a combined image we found an object which is marginally visible in DSS2(R) and not presented in USNO-B1.0; coordinates of the object are (J2000) RA= 06h 10m 38.4s Dec= +70 09 32.4 with uncertainty in both coordinates of about 0.1". Brightness of the object is measured in the combined image is R=19.2 +/-0.1. The object is not variable between the two epochs within error bars. The astrometry and photometry calibration is based on USNO-B1.0.
While the object is not variable between our epochs and marginally visible in DSS2(R) and detected better in DSS2(I), the object may be a host galaxy of GRB060204C if fading brightness of the object will be confirmed.
The stacked image can be found in http://grb.rssi.ru/GRB060204c/grb060204C_Z600_R.jpg
GCN Circular #4679
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. Barthelmy (GSFC), P. Boyd (GSFC-UMBC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), J. Tueller (GSFC), W. Voges (MPE) on behalf of the Swift-BAT team:
Using the data set from T-299.0 to T+303.1 sec from the recent telemetry downlink, we report further analysis of BAT trigger #180274 (Grupe, et al., GCN 4663). The BAT ground-calculated position is (RA,Dec) = 92.715, 70.174 deg {6h 10m 58.5s, 70d 10' 41.7"} (J2000) +- 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a single broad peak in the 15-50 keV band with no significant emission above 50 keV. T90 (15-350 keV) is (60 +- 5) sec (estimated error including systematics).
The time-averaged spectrum from T+0 to T+64 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.4 +- 0.6. The fluence in the 15-150 keV band is (3.5 +- 1.2) x 10^-07 erg/cm2. The average photon flux measured from T+0 to T+64 sec in the 15-150 keV band is (0.10 +- 0.03) ph/cm2/sec. All the quoted errors are at the 90% confidence level.
This source was detected at the 4.8-sigma level 1.5 days earlier at the same location. There is 0.1% probability that this pre-trigger detection is a chance coincidence. This plus the very soft nature of the spectrum forces us to conclude that this is probably not a real GRB, but is very likely a hard X-ray transient.
Further analysis has shown that even though the star tracker had a loss-of-lock during the initial trigger, the tracking error was much smaller than our stated location uncertainty.
GCN Circular #4681
authors: D. Grupe (PSU), D. Burrows (PSU)., D. Morris (PSU), T. Sakamoto (GSFC), N. Cucchiara (PSU), A. Retter (PSU), S. Barthelmy (GSFC) on behalf of the Swift team
We report on the analysis of the X-ray source Swift J061223.0+701243.9 which is inside the Field of view of BAT trigger 180274 (GRB 060204C). As discussed by Grupe et al (GCN 4672) this source is about 8' away from the BAT position reported by Grupe et al. (GCN 4663). The XRT position of this source is:
```
RA-2000:   06 12 22.97
Dec-2000: +70 12 43.9
```
with an error radius of 3.6" Note that even though there was a star tracker loss-of-lock during the initial trigger, we consider this position as very reliable. The total exposure time of the field is 22.6 ks which were acquired within 58.2 ks.
The light curve initially shows a brightening followed by a decreasing count rate starting about 10 ks after the trigger. Below we list the light curve with time after the trigger (in seconds), count rate and count rate error (in units of XRT counts/s):
```
Time          cr     cr_err      
------------  -------  ----------
 2.61399e+02   1.82e-02  7.03e-03
 5.25616e+03   5.94e-02  4.88e-03
 1.10075e+04   6.39e-02  5.06e-03
 1.68026e+04   3.43e-02  3.65e-03
 2.18468e+04   5.66e-02  6.91e-03
 2.75906e+04   5.16e-02  7.24e-03
 3.43580e+04   2.06e-02  2.92e-03
 4.03060e+04   4.35e-02  4.20e-03
 4.61773e+04   3.19e-02  3.61e-03
 5.20307e+04   2.07e-02  2.89e-03
 5.63931e+04   2.23e-02  3.34e-03
```
The spectral analysis shows excess absorption above the Galactic value (9e20 cm-2) with 18.8+2.9-6.1 with a photon index Gamma = 1.52+0.16-0.15. Because we do not know the nature of this X-ray transient source (it was not present in the ROSAT All-Sky Survey) we encourage optical observers to derive a spectrum to identify the source.
Due to the distance of 8' away from the BAT position we do not consider this X-ray source an afterglow of GRB 060204C. As discussed by Sakamoto et al (GCN 4679) BAT trigger 180274 is most likely not a real GRB and probably a hard X-ray transient. We have no further plan to re-observe the field of BAT trigger 180274.

Back to JG's homepage

Jochen Greiner, last update: 06-Feb-2006 [Disclaimer]