GRB 051006
GCN Circular 4061
Subject
GRB051006: Swift detection of a burst
Date
2005-10-06T21:32:24Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
J. Norris (GSFC), S. Barthelmy (GSFC), D. Burrows (PSU), M. Capalbi (ASDC),
N. Gehrels (GSFC), S.T. Holland (GSFC), J. Kennea (PSU),
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Morris (PSU),
J. Nousek (PSU), C. Pagani (PSU), D. Palmer (LANL), P. Roming (PSU)
on behalf of the Swift team:
At 20:30:33 UT, Swift-BAT triggered and located GRB051006 (trigger=158593).
The spacecraft slewed immediately. The BAT on-board calculated location
is RA,Dec 110.830d,+9.531d {07h 23m 19s,+09d 31' 50"} (J2000), with an
uncertainty of 3 arcmin (radius, 90% containment, stat+sys).
The BAT light curve shows a multi-peak structure with a total duration
of ~20 sec. The peak count rate was ~1500 counts/sec (15-350 keV),
at ~3 seconds after the trigger.
XRT began observing the field at 20:32:21.46, 108 seconds after the
BAT trigger. No prompt X-ray position is available. The XRT lightcurve
suggests a fading source is present in the field of view. The TDRSS
downlinked spectrum is inconclusive. Further analysis of the XRT data
will be reported when the full data set becomes available.
The UVOT began observing the position of trigger #158593 at 20:32:20.4 UT,
107 s after the BAT trigger. In the 200 s V-band image, no new source is
detected with respect to the DSS down to a 3-sigma limiting mag of 18.8.
The estimated extinction in this direction is A_V ~ 0.2 magnitudes.
The UVOT image gives 25% coverage of the BAT error circle. The BAT source
is located in a crowded star field.
GCN Circular 4062
Subject
GRB 051006: XRT position
Date
2005-10-06T22:54:23Z (20 years ago)
From
David Morris at PSU/Swift-XRT <morris@astro.psu.edu>
D. Morris (PSU), C. Pagani (PSU/OAB), M. Capalbi (ASDC), J. Kennea
(PSU), D. Burrows (PSU) report on behalf of the Swift/XRT team:
The Swift XRT began observing GRB 051006 (trigger #158593, Norris et
al., GCN 4061) at 20:32:21 UT, but was unable to obtain an on-board
centroid. Analysis of the initial ground-processed data finds a faint,
fading, and uncataloged source at coordinates:
RA(J2000) = 07 23 13.9
Dec(J2000) = +09 30 22.5
We estimate an uncertainty of 8 arcseconds (90% containment). This
position lies 118 arcseconds from the BAT position reported in GCN 4061.
GCN Circular 4063
Subject
GRB051006: Refined analysis of the Swift-BAT burst
Date
2005-10-06T23:15:49Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
K. Gendreau (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), P. Meszaros (PSU), 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 Trigger #158593 (Norris, et al., GCN 4061).
The ground-analysis position is RA,Dec 110.808,+9.510
{7h 23m 13.8s,+9d 30' 36.3"} (J2000) with an uncertainty
of 1.7 arcmin (radius, 90%, stat+sys). T90 is 26 +- 1 sec.
The lightcurve has an initial cluster of 3 overlapping peaks at T-5 to T+8 sec
and a fourth peak at T+20 sec. Fitting a simple power law
over the full interval from T-5.9 to T+24.7 sec, the photon index
is 1.4 +/- 0.2 with a fluence of 1.28 +/- 0.13 X 10^-6 erg/cm^2.
The peak flux in a 1-sec wide window starting at T+3.2 sec
is 1.9 +/- 0.3 ph/cm^2/sec. All values are in the 15-150 keV band
at the 90% confidence level.
GCN Circular 4064
Subject
GRB 051006: optical observations at Sierra Nevada
Date
2005-10-07T13:55:32Z (20 years ago)
Edited On
2024-11-18T10:09:39Z (6 months ago)
From
Alberto Castro-Tirado at LAEFF-INTA <ajct@laeff.esa.es>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
A. de Ugarte, A.J. Castro-Tirado, S. Guziy, V.
Casanova, M. Jelínek and J. Gorosabel (IAA-CSIC):
report:
"We have imaged a 7' x 7' region centred on the SWIFT/
BAT error box for GRB 051006 (Norris et al. GCNC 4061)
with the 1.5-m OSN telescope at the Observatorio de
Sierra Nevada starting on Oct 6.105 UT, i.e. 6.0 hours
after the onset of the event) under fair meteorological
conditions. Within the SWIFT/XRT error box (Morris et
al. GCNC 4062), the co-added I-band image (10 x 300 s
exposure time) shows three sources at the following
coordinates (J2000):
ID RA Dec
#1 07 23 13.85 +09 30 28.3
#2 07 23 14.11 +09 30 20.4
#3 07 23 13.61 +09 30 23.7
with 0.4" error. Source 1 is a bright star present in
the DSS-2. Source 2 is also present in the DSS-2 (blue).
Source 3 is below the detection limit of the DSS-2.
Additional observations will continue tonight (if weather
permits)."
GCN Circular 4066
Subject
GRB 051006: XRT refined analysis
Date
2005-10-07T18:04:32Z (20 years ago)
From
Milvia Capalbi at ISAC/ASDC <capalbi@asdc.asi.it>
M. Capalbi, M. Perri (ASDC), J. Kennea, D.N. Burrows, D. Morris (PSU),
L. Angelini (GSFC-JHU), J. Greiner (MPE) report on behalf of the Swift
XRT team:
We have analyzed the first six orbits of the Swift XRT data for GRB
051006 ((trigger #158593, Norris et al., GCN 4061). The refined
coordinates of the X-ray afterglow are:
RA(J2000) = 07 23 13.7
Dec(J2000) = +09 30 20.3
with an estimated uncertainty of 8 arcseconds radius (90% containment).
This position is 16 arcseconds from the BAT refined position (Palmer et
al., GCN 4063), 3.7 arcseconds from the early XRT position (Morris et
al., GCN 4062) and 3.7 arcseconds from the optical source reported by de
Ugarte et al. (GCN 4064).
Data in Windowed Timing (WT) mode starts at 20:32:26 UT, 113 seconds
after the BAT trigger, then the XRT switched to Photon Counting mode.
The light curve shows a flaring behaviour in the first orbit,and has a
decay index of -1.7 +/- 0.05 obtained excluding the flare time interval.
A preliminary spectral fit (simple absorbed power-law) to the WT data
yields a photon index of 1.6 +/- 0.4 in the 0.7-10 keV band.
The derived NH is (7 +/- 3)E21 cm^-2, which is higher than the Galactic
value (8.6E+20 cm-2; Dickey & Lockman 1990).
GCN Circular 4068
Subject
GRB 051006: P60 Observations
Date
2005-10-07T21:28:48Z (20 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. Bradley Cenko, Alicia M. Soderberg (Caltech) and Derek B. Fox (Penn
State) report on behalf of a larger collaboration:
We have imaged the field of GRB 051006 (Norris et al., GCN 4061) with
the automated Palomar 60-inch telescope. Observations consisted of 10 x
150 s R-band images taken at a mean epoch of approximately 9:20, 7
October UT (12.9 hours after the burst). In a co-addition of our
images, we find no new sources inside the refined XRT error circle
(Capalbi et al., GCN 4066). Using several Guide Star Catalog sources in
the field, we estimate our limiting magnitude to be R > 21.0.
In particular, we do not detect source #3 identified by de Ugarte et al.
(GCN 4064) to the magnitude limit quoted above.
GCN Circular 4089
Subject
GRB 051006: Swift/UVOT Upper Limits
Date
2005-10-12T14:23:12Z (20 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
GRB 051006: Swift/UVOT Upper Limits
S. T. Holland (GSFC/USRA), J. Norris (GSFC), J. Greiner (MPE),
D. Hinshaw (GSFC-SPSYS), and N. Gehrels (GSFC) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 051006 107
seconds after the BAT trigger (Norris et al. GCN 4061). No new source
is detected at the position of the XRT error circle (Capalbi et
al. GCN 4066) in the initial 200 second V-band image down to a 5-sigma
upper limit of 18.3, or in summed exposures with any of the filters
down to the following 5-sigma magnitude upper limits.
Filter T_range (s) Exp (s) 5sig UL
V 107 - 98,547 12,033 20.5
B 474 - 68,573 4,111 20.9
U 420 - 64,478 3,846 20.4
UVW1 366 - 63,741 4,598 21.0
UVM2 311 - 73,819 4,179 21.3
UVW2 582 - 69,481 5,448 21.6
WHITE 527 - 577 50 18.5
These magnitudes have not been corrected for extinction.
GCN Circular 4094
Subject
GRB051006: optical observations
Date
2005-10-14T15:15:37Z (20 years ago)
From
Vasilij Rumjantsev at CrAO <rum@crao.crimea.ua>
V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), A.Pozanenko (IKI), M. Ibrahimov
(MAO) on behalf of larger GRB follow up collaboration report:
We have observed the GRB051006 error box (Norris et al., GCN4061) with 2.6 m
Shajn telescope of CrAO on October 7 and 8 in R-band. On Oct.8 within XRT
error circle (Capalbiet al., GCN4066) we detect source #3 quoted by Ugarte
et al. (GCN 4064). The coordinate of the source is
RA(J2000) = 07 23 13.52
Dec = +09 30 24.48
with uncertainty 0.4 arcsec in both coordinates. The photometry of the
source against of USNO A2.0 is following
Mid time Exposure R
Oct.8 (UT)
02:28 35x120 s 22.20 +/-0.15
The stacked image of the Oct.8 observation can be found in
http://grb.rssi.ru/GRB051006/grb051006_051008_ZTSh_R.gif
Taking into account the upper limit of R>21.0 at 12.9 hours after the burst
(Bradley Cenko at al., GCN 4068) and our result above one can estimate the
power law decay index of possible afterglow source #3 as alpha >-1.37.
In our observation on Oct.7 between 02:23 - 02:44 (UT) due to unfavorable
weather conditions the seeing was ~5 arcsec. At this time we could not
confirm the presence of source #3 in the tail of nearby bright star.
Detailed analysis in underway.
This message can be cited.