Gamma-ray Burst 061218

(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:     Mon 18 Dec 06 04:06:03 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     251863,   Seg_Num: 0
GRB_RA:          149.223d {+09h 56m 53s} (J2000),
                 149.298d {+09h 57m 12s} (current),
                 148.683d {+09h 54m 44s} (1950)
GRB_DEC:         -35.146d {-35d 08' 45"} (J2000),
                 -35.180d {-35d 10' 45"} (current),
                 -34.908d {-34d 54' 27"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       21707 [cnts]    Image_Peak=381 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   448     E_range: 15-50 keV
BKG_INTEN:       187230 [cnts]
BKG_TIME:        14646.35 SOD {04:04:06.35} UT
BKG_DUR:         40 [sec]
GRB_DATE:        14087 TJD;   352 DOY;   06/12/18
GRB_TIME:        14705.81 SOD {04:05:05.81} UT
GRB_PHI:           5.77 [deg]
GRB_THETA:        17.11 [deg]
SOLN_STATUS:     0x83
RATE_SIGNIF:     9.00 [sigma]
IMAGE_SIGNIF:    6.71 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +1  -1  +0  +0 +10  +1 
SUN_POSTN:       265.74d {+17h 42m 56s}  -23.38d {-23d 22' 47"}
SUN_DIST:         96.05 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      233.90d {+15h 35m 36s}  -24.00d {-24d 00' 01"}
MOON_DIST:        72.27 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.13, 15.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      167.57,-44.00 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 67.00,-16.21 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 Dec 06 04:07:07 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.209d {+09h 56m 50s} (J2000)
POINT_DEC:       -35.140d {-35d 08' 24"} (J2000)
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14811.84 SOD {04:06:51.84} UT,   106.0 [sec] since BAT Trigger Time
COUNTS:          3    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:     Mon 18 Dec 06 04:08:41 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     251863,   Seg_Num: 0
GRB_RA:          149.223d {+09h 56m 53s} (J2000),
                 149.298d {+09h 57m 12s} (current),
                 148.683d {+09h 54m 44s} (1950)
GRB_DEC:         -35.146d {-35d 08' 45"} (J2000),
                 -35.180d {-35d 10' 45"} (current),
                 -34.908d {-34d 54' 27"} (1950)
GRB_DATE:        14087 TJD;   352 DOY;   06/12/18
GRB_TIME:        14705.81 SOD {04:05:05.81} UT
TRIGGER_INDEX:   448
GRB_PHI:           5.77 [deg]
GRB_THETA:        17.11 [deg]
DELTA_TIME:      -24.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x83
RATE_SIGNIF:     9.00 [sigma]
IMAGE_SIGNIF:    6.71 [sigma]
LC_URL:          sw00251863000msb.lc
SUN_POSTN:       265.74d {+17h 42m 57s}  -23.38d {-23d 22' 47"}
SUN_DIST:         96.05 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      233.93d {+15h 35m 42s}  -24.01d {-24d 00' 23"}
MOON_DIST:        72.28 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.13, 15.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      167.57,-44.00 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 67.00,-16.21 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 Dec 06 04:09:38 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.210d {+09h 56m 50s} (J2000)
POINT_DEC:       -35.140d {-35d 08' 24"} (J2000)
POINT_ROLL:      124.322d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14815.39 SOD {04:06:55.39} UT,   109.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.304
N_STARS:         98
X_OFFSET:        563 [pixels]
Y_OFFSET:        520 [pixels]
X_MAX:           1522 [pixels]
Y_MAX:           1479 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00251863000msufc0109.fits
SUN_POSTN:       265.74d {+17h 42m 57s}  -23.38d {-23d 22' 47"}
SUN_DIST:         96.06 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      233.93d {+15h 35m 44s}  -24.01d {-24d 00' 31"}
MOON_DIST:        72.30 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 Dec 06 04:11:17 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.210d {+09h 56m 50s} (J2000)
POINT_DEC:       -35.140d {-35d 08' 24"} (J2000)
ROLL:            124.322d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14815.39 SOD {04:06:55.39} UT,   109.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     188107617
X_OFFSET:        882 [pixels]
Y_OFFSET:        839 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1042
Y_GRB_POS:       999
BINNING_INDEX:   1
IM_URL:          sw00251863000msuni0109.fits
SUN_POSTN:       265.74d {+17h 42m 57s}  -23.38d {-23d 22' 48"}
SUN_DIST:         96.06 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      233.95d {+15h 35m 48s}  -24.01d {-24d 00' 45"}
MOON_DIST:        72.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [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:     Mon 18 Dec 06 04:11:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.210d {+09h 56m 50s} (J2000)
POINT_DEC:       -35.140d {-35d 08' 24"} (J2000)
ROLL:            124.322d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14815.39 SOD {04:06:55.39} UT,   109.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     188107617
X_OFFSET:        882 [pixels]
Y_OFFSET:        839 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1042
Y_GRB_POS:       999
BINNING_INDEX:   1
IM_URL:          sw00251863000msuni0109.fits
SUN_POSTN:       265.74d {+17h 42m 57s}  -23.38d {-23d 22' 48"}
SUN_DIST:         96.06 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      233.95d {+15h 35m 48s}  -24.01d {-24d 00' 47"}
MOON_DIST:        72.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [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:     Mon 18 Dec 06 04:18:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.211d {+09h 56m 51s} (J2000)
POINT_DEC:       -35.138d {-35d 08' 15"} (J2000)
POINT_ROLL:      124.320d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14921.05 SOD {04:08:41.05} UT,   215.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        2.976
N_STARS:         116
X_OFFSET:        563 [pixels]
Y_OFFSET:        520 [pixels]
X_MAX:           1522 [pixels]
Y_MAX:           1479 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00251863000msufc0215.fits
SUN_POSTN:       265.75d {+17h 42m 59s}  -23.38d {-23d 22' 48"}
SUN_DIST:         96.07 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      234.02d {+15h 36m 05s}  -24.03d {-24d 01' 50"}
MOON_DIST:        72.36 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 Dec 06 04:20:24 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.211d {+09h 56m 51s} (J2000)
POINT_DEC:       -35.138d {-35d 08' 15"} (J2000)
ROLL:            124.320d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14921.05 SOD {04:08:41.05} UT,   215.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     188107722
X_OFFSET:        882 [pixels]
Y_OFFSET:        839 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1042
Y_GRB_POS:       999
BINNING_INDEX:   1
IM_URL:          sw00251863000msuni0215.fits
SUN_POSTN:       265.75d {+17h 42m 59s}  -23.38d {-23d 22' 48"}
SUN_DIST:         96.07 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      234.03d {+15h 36m 08s}  -24.03d {-24d 02' 02"}
MOON_DIST:        72.36 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [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:     Mon 18 Dec 06 04:20:43 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     251863,   Seg_Num: 0
POINT_RA:        149.211d {+09h 56m 51s} (J2000)
POINT_DEC:       -35.138d {-35d 08' 15"} (J2000)
ROLL:            124.320d
IMG_START_DATE:  14087 TJD;   352 DOY;   06/12/18
IMG_START_TIME:  14921.05 SOD {04:08:41.05} UT,   215.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     188107722
X_OFFSET:        882 [pixels]
Y_OFFSET:        839 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1042
Y_GRB_POS:       999
BINNING_INDEX:   1
IM_URL:          sw00251863000msuni0215.fits
SUN_POSTN:       265.75d {+17h 42m 59s}  -23.38d {-23d 22' 48"}
SUN_DIST:         96.07 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      234.04d {+15h 36m 09s}  -24.03d {-24d 02' 05"}
MOON_DIST:        72.37 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:      267.11, 15.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      167.55,-43.99 [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 #5936
S. Zane (UCL-MSSL), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), S. R. Oates (UCL-MSSL), C. Pagani (PSU), D. M. Palmer (LANL) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team:
At 04:05:05 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger=251863. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 149.223, -35.146 which is
```
   RA(J2000)  =  09h 56m 53s
   Dec(J2000) = -35d 08' 45"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a possible very weak pulse lasting about 10 sec, overlying the much stronger periodic variation of Vela X-1 in the same field. The peak count rate was ~500 counts/sec (15-350 keV), at ~1 sec before the trigger.
The XRT began taking data at 04:06:51 UT, 106 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. No source is detected in 275s of quicklook photon counting mode data.
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 110 seconds after the BAT trigger, and a finding chart exposure of nominal 400 seconds with the V filter starting 216 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 18.5 mag (in White). 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 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.125
GCN Circular #5937
P. D'Avanzo, S. Covino, E. Molinari, G. Chincarini, F.M. Zerbi, V. Testa, G. Tosti, F. Vitali, P. Conconi, L.A. Antonelli, G. Cutispoto, G. Malaspina, L. Nicastro, E. Palazzi, E. Meurs, and P. Goldoni report on behalf of the REM/ROSS team
We observed the field of the possible GRB 061218 (Zane et al. GCN 5936) with the robotic 60-cm REM telescope located at La Silla (Chile). A set of observations was performed automatically in the optical and near infrared filters (V, R, I and J, H, K, z) starting on 2006 December 18 at 04:07:14 UT, 71 s after the BAT trigger and 129 s after the GRB time.
Preliminary analysis of the whole dataset does not show any new variable source inside the BAT error box.
The 3-sigma limiting magnitudes are:
```
   R~18.6
   J~16.7
   H~16.0
   K~15.3
```
This message may be cited.
GCN Circular #5938
B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 061218 (GCN 5936, Zane et al.), with a mid-exposure time of 2006-12-18 04:44:48 UT, which is ~0.7 hours post-burst. Our optical images have a field of view of 6'x6' and, therefore, cover the entire GRB error circle. Our IR images have a smaller field of view, covering a region totaling ~6 square arcminutes in the middle of the quoted error region. Several dithered images were obtained in each filter, with total summed exposure times of 180s in each of BRIYJK and 120s in each of H and V.
Preliminary visual comparison of the optical images to the DSS and the IR images to 2MASS frames does not reveal any new sources to the limit of the comparison frames.
GCN Circular #5940
G. Sato (GSFC/ISAS), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), S. Zane (UCL-MSSL) on behalf of the Swift-BAT team:
Using the data set from T-120 to T+183 sec from the recent telemetry downlink, we report further analysis of BAT GRB 061218 (trigger #251863) (Zane, et al., GCN Circ. 5936). The BAT ground-calculated position is RA, Dec = 149.238, -35.221 deg which is
```
   RA(J2000)  =  09h 56m 57.0s 
   Dec(J2000) = -35d 13' 15.9" 
```
with an uncertainty of 4 arcmin, (radius, sys+stat, 90% containment). The burst was in the fully-coded field of view.
The mask-weighted lightcurve consists of a single very weak pulse lasting about 7 sec. T90 (15-350 keV) is 4.1 +- 0.5 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+4.1 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.76 +- 0.63. The fluence in the 15-150 keV band is 4.1 +- 1.5 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.2 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5941
S. Karpov, G. Beskin, S. Bondar, C. Bartolini, G. Greco, A. Guarnieri, D. Nanni, A. Piccioni, F. Terra, E. Molinari, G. Chincarini, F.M. Zerbi, S. Covino, V. Testa, G. Tosti, F. Vitali, L.A. Antonelli, P. Conconi, G. Cutispoto, G. Malaspina, L. Nicastro, E. Palazzi, E. Meurs, P. Goldoni
report on behalf of the TORTOREM team:
The field of GRB 061218 (Zane et al. GCN 5936) has been observed by the TORTORA (Telescopio Ottimizzato per la Ricerca di Transienti Ottici RApidi) wide-field fast camera (12 cm diameter, 20x25 deg FOV) mounted on REM robotic 60-cm telescope located at La Silla (Chile). The burst was initially outside the camera field of view. The system was repointed and the TORTORA began to acquire frames at 04:07:03 UT (118 sec after trigger) with 7.5 Hz frame frequency (0.128 s exposure).
The summation of 100 frames with 12.8 s. effective exposure (middle time 04:07:16 UT) did not reveal any source down to the B = 11.3 mag (3-sigma).
We performed the Fourier analysis of 23 min data set (10000 successive frames) to search for the periodic signal at the GRB position. The upper limit for the amplitude of sinusoidal variability is B=16.4 (3-sigma) over the 0.01 - 3.5 Hz range.
The message may be cited.
GCN Circular #5943
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 061218 detected by SWIFT (trigger 251863) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 126.5s after the GRB trigger (69.6s after the notice). The elevation of the field increased from from 30 degrees above horizon and weather conditions were good.
The date of trigger : t0 = 2006-12-18T04:05:06.144
A technichal problem prevent to obtain a 60s image at t0+58s. Moreover, images are slightly defocussed.
We examined the BAT position provided by Sato et al. 2006 (GCN Circ. 5940).
The first image is 30.0s exposure in tracking mode: We do not detect any OT with a limiting magnitude of: t0+126.5s to t0+156.5s : R > 17.4
The second image is 30.0s exposure: t0+162.3s to t0+192.3s : R > 17.4
We co-added a series of exposures: t0+126.5s to t0+510.6s : R > 18.0
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=267.1250 lat=+15.3187 and the galactic extinction in R band is 0.3 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.
GCN Circular #5980
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We solve technichal problems that prevent to acces to the first trailed image of GRB 061218 obtained with TAROT located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 61s after the GRB trigger (4s after the notice). The trailed image allows to follow continuously variable sources during the 60s integration time (see technichal description in Klotz et al., 2006, A&A 451, L39). We analyzed the GRB error box provided by Sato et al. GCN Circ. 5940. No variable object is detected. To summarize:
```
t0+ 61.0s to t0+121.0s : R > 15.8
t0+126.5s to t0+156.5s : R > 17.4 (CGNC 5943)
t0+162.3s to t0+192.3s : R > 17.4 (CGNC 5943)
t0+126.5s to t0+510.6s : R > 18.0 (CGNC 5943)
```
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
This message may be cited.

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Jochen Greiner, last update: 25-Dec-2006 [Disclaimer]