GRB 051117, GRB 051117A
GCN Circular 5025
Subject
GRB 051117A: Bright host galaxy not confirmed
Date
2006-04-28T16:16:33Z (20 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
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D. A. Kann (TLS Tautenburg), E. Palazzi, N. Masetti & E. Maiorano (INAF/IASF - Bologna) report:
We observed the location of the UVOT afterglow (Holland et al., GCN 4300, Holland, GCN 4301) of GRB 051117A (Band et al., GCN 4280) with the Tautenburg 1.34m Schmidt telescope in the R filter under clear conditions and seeing of 2.8". Observations consisted of 12 x 600 s exposures, total integration time 2 hours, centered at UT 20060406.1, 139.9 days after the burst.
It was suggested by the UVOT observations that an underlying extended source might have been detected at 3.5 days after the burst at a magnitude of V about 21.5 - possibly the host galaxy.
The stacked Tautenburg image reveals no source at the UVOT position. The limiting magnitude at 3 sigma confidence is R = 24.0 measured against the USNOB1.0 R2 magnitudes of several unsaturated and isolated stars. This is not corrected for the very small Galactic extinction of E(B-V) = 0.024.
This field has also been imaged by the fourth release of the Sloan Digital Sky Survey (Adelman-McCarthy et al. 2006, ApJS, in press), and no source is detected at the UVOT location either (our photometry is significantly deeper than the SDSS).
About 2" from the UVOT localization (outside the 3 sigma UVOT localization), there is a group of four pixels slightly above the (subtracted) background. Simply transforming the sum of the counts into a magnitude gives R = 25.3, a "detection" at about one sigma significance. We caution that this is quite probably not a real source. There are no other sources closer than 5" to the UVOT position.
This message may be cited.
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GCN Circular 4301
Subject
GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
Date
2005-11-22T21:11:22Z (21 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
S. T. Holland (GSFC/USRA), on behalf of the Swift/UVOT team report:
There is an error in the coordinates for the UVOT fading
source associated with GRB 051117A (Holland et al., 2005, GCN
Circular 4300). The correct coordinates are
RA(J2000) = 15:13:34.09
Dec(J2000) = +30:52:12.7
with a positional uncertainty of +/-0.5 arcsec (1-sigma). We
apologize for this error and any inconvenience that it may
have caused.
GCN Circular 4300
Subject
GRB 051117A: Swift/UVOT Detection of an Afterglow
Date
2005-11-22T19:02:07Z (21 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
GRB 051117A: Swift/UVOT Detection of an Afterglow
S. T. Holland (GSFC/USRA), D. Band (GSFC), K. Mason (PPARC),
F. Marshall (GSFC), & N. Gehrels (GSFC) on behalf of
the Swift/UVOT team report:
The Swift/UVOT began observing the field of GRB 051117A (BAT
Trigger 163268; Band et al. 2005, GCN Circular 4280) at
2005-11-17T10:53:10, 111 seconds after the burst.
We detect a fading source corresponding to the UVOT source
in Band et al. (2005, GCN Circular 4280). The refined coordinates
of this source are:
RA(J2000) = 15:13:39.09
Dec(J2000) = +30:52:12.7
with a positional uncertainty of +/-0.5 arcsec (1-sigma). The
transient has V = 20.01 +/- 0.46 (1-sigma, statistical) in a 200 s
exposure starting at 110 seconds after the BAT trigger. This value
supersedes the approximate magnitude given in Band, et al. (2005, GCN
Circular 4280). This magnitude has not been corrected for Galactic
extinction.
The magnitude in the UVOT White filter is 19.19 +/- 0.16
(1-sigma, statistical) in a 50 s, exposure starting 531 s after the
BAT trigger. The source has faded to a White magnitude of
approximately 21.5 by 3.5 days after the burst. There is weak
evidence that the source is extended, so this may represent the
luminosity of the host galaxy of GRB 051117A.
GCN Circular 4292
Subject
GRB 051117A and B: Radio Observations
Date
2005-11-18T13:26:37Z (21 years ago)
From
Dale A. Frail at NRAO <dfrail@nrao.edu>
Dale A. Frail (NRAO) reports on behalf of a larger collaboration:
"We observed both recent bursts, GRB 051117A (GCN 4280) and GRB
051117B (GCN 4281) with the Very Large Array at 8.5 GHz centered on
November 18.51 UT and 18.48, respectively. Within the XRT error
circles (GCN 4282; GCN 4287) we no radio emission above 3-sigma, for
an rms noise of 56 uJy (GRB 051117A), and 40 uJy (GRB 051117B).
No further observations are planned.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 4289
Subject
GRB 051117A: Refined analysis of the Swift-BAT burst
Date
2005-11-17T21:52:20Z (21 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
L. Cominsky (Sonoma State U.), J. Cannizzo (GSFC-UMBC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink,
we report further analysis of Swift-BAT GRB 051117A (trigger #164268)
(Band, et al., GCN 4280). The ground-analysis position is
RA,Dec 228.399,+30.870 {15h 13m 35.7s,+30d 51' 10.3"} (J2000)
with an uncertainty of 1.0 arcmin (radius, 90%, stat+sys).
T90 is at least 140 +- 10 sec. The partial coding fraction is 72%.
The lightcurve has a long FRED-like peak at T-15 sec
lasting out to at least T+190 sec. There is a hint of emission
peaks at T+225 and T+350 (each ~30 sec in duration).
Fitting a simple power law over the interval from T-29 to T+157 sec,
the photon index is 1.83 +/- 0.07 with a fluence of at least
4.6 +/- 0.16 X 10^-6 erg/cm^2. The peak flux in a 1-sec wide window
starting at T+2.47 sec is 0.93 +/- 0.17 ph/cm^2/sec. All values are
in the 15-150 keV band at the 90% confidence level.
GCN Circular 4287
Subject
GRB051117A : XRT refined analysis
Date
2005-11-17T19:32:08Z (21 years ago)
From
Michael Goad at U Leicester <mrg@star.le.ac.uk>
M. Goad, K. Page, D. Burrows (PSU), K. Hurley, (Berkeley), M. Chester (PSU)
report on behalf of the Swift XRT team.
From analysis of 2.3 ks of Photon Counting mode data of GRB051117A (Band et
al., GCN 4280) we obtain a refined XRT position of RA: 15h 13m 33.8s, Dec:+30d
52m 13.3s (J2000) with an uncertainty of 3.4 arcsec (90% containment). This
includes the latest XRT boresight correction. This refined position is 41
arcsec from the BAT on-board position and 3.4 arcsec from the UVOT position
quoted in GCN 4280.
We have also analysed 1.77 ks of XRT Windowed Timing mode observations
starting 113 s after the BAT trigger. The XRT lightcurve displays multiple
flares with a peak count rate of approximately 180 ct/s occurring 134 s after
the BAT trigger. The early underlying decay slope of the XRT lightcurve is a
powerlaw with slope ~1.1+/-0.1.
The XRT WT mode 0.2-10 keV spectrum is well represented by an absorbed
powerlaw with photon index 2.23+/-0.02 with a mean unabsorbed flux of 2.6E-09
ergs/cm2/s (between 113 s and 5.2 ks after the burst). We find evidence for
excess NH above the Galactic value of 2.0e21 cm^-2.
GCN Circular 4280
Subject
GRB 051117: Swift detection of a bright burst
Date
2005-11-17T11:44:49Z (21 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
D. Band (GSFC), S. Barthelmy (GSFC), A. Beardmore (U Leicester),
D. Burrows (PSU), N. Gehrels (GSFC), M. Goad (U. Leicester)
O. Godet (U. Leicester), C. Gronwall (PSU), J. Kennea (PSU),
K. Page (U Leicester), E. Rol (U. Leicester)
on behalf of the Swift team:
At 10:51:20 UT, Swift-BAT triggered and located GRB 051117 (trigger=164268).
The spacecraft slewed immediately. The BAT on-board calculated location
is RA,Dec 228.405d, +30.870d {+15h 13m 37s, +30d 52' 11"} (J2000),
with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys).
The BAT light curve shows a single peak with a total duration
of about 20 sec. The peak count rate was ~1500 counts/sec (15-350 keV),
at ~3 sec after the trigger.
XRT began observing at 10:53:07 UT, 107 seconds after the BAT trigger.
We find a bright, rapidly fading, uncataloged source at RA 15h 13m 33.7s
Dec +30d 52' 22.0" (J2000) with a positional uncertainty of 5.8 arcsec
(90% containment). This is 46 arcsec from the BAT position. The
approximate initial flux is 1.0e-8 erg/cm2/sec (0.2-10 keV). The XRT
preliminary raw spectrum is well fit by an absorbed powerlaw with a
photon index of 2.2+/- 0.1 with an excess NH of 2e21 cm^-2.
UVOT began observing at UT 10:53:10, 111 seconds after the BAT trigger.
In a 200 sec V image, we detect a faint source just outside the XRT
error circle at an approximate position of RA=15h 13m 33.6s, Dec=30d 52' 15.2"
(J2000) that is not present in the DSS. The magnitude is 19.9 mag.
The extinction in this direction is A_V = 0.08.