GRB 100117A
GCN Circular 10336
Subject
GRB 100117A: Swift detection of a short hard burst
Date
2010-01-17T21:19:26Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. De Pasquale (UCL-MSSL), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), S. Campana (INAF-OAB), P.A. Curran (MSSL-UCL),
N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
V. Mangano (INAF-IASFPA), R. Margutti (Univ Bicocca&OAB),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
C. Pagani (PSU), D. M. Palmer (LANL), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/IASFPA),
M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 21:06:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 100117A (trigger=382941). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 11.260, -1.594 which is
RA(J2000) = 00h 45m 02s
Dec(J2000) = -01d 35' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single spike
structure with a duration of about 0.4 sec. The peak count rate
was ~4500 counts/sec (15-350 keV), at T_zero.
The XRT began observing the field at 21:07:39.6 UT, 80.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 11.26946, -1.59620 which
is equivalent to:
RA(J2000) = 00h 45m 4.67s
Dec(J2000) = -01d 35' 46.3"
with an uncertainty of 4.6 arcseconds (radius, 90% containment). This
location is 34 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.66e+20
cm^-2, Kalberla et al. 2005), with an excess column of 4 (+3.65/-2.58)
x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 1.24e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 88 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
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
0.02.
Burst Advocate for this burst is M. De Pasquale (mdp AT mssl.ucl.ac.uk).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular 10337
Subject
GRB100117A: Possible afterglow from NOT observation
Date
2010-01-17T23:14:51Z (15 years ago)
From
Dong Xu at DARK,NBI <dong@astro.ku.dk>
D. Xu (WIS, DARK/NBI), D. Malesani, G. Leloudas, J.P.U. Fynbo
(DARK/NBI), A.A. Djupvik, R. Karjalainen (NOT), N.R. Tanvir (U.
Leicester), P. Jakobsson (Univ. of Iceland) report on behalf of a larger
collaboration:
We observed the field of GRB100117A (De Pasquale et al., GCN 10336) with
the Nordic Optical Telescope equipped with StanCam and NOTCam, starting
at 21:26:40 UT on Jan 17th, 20.35 mins after the burst trigger. The
observations were carried out at high airmass (~2) and in poor seeing.
In a 900 s R-band image, starting at 21:48:42 UT, we notice the presence
of a faint, marginally significant object at coordinates:
RA(J2000)=00h 45m 04.75s
Dec(J2000)=-01d 35' 47.4"
with an error circle of 0.5 arcsec. If real, its magnitude is R =
22.5+/-0.5.
The co-addition of a series of K-band images doesn't show any convincing
counterpart on the position.
GCN Circular 10338
Subject
GRB 100117A: Swift-BAT refined analysis
Date
2010-01-17T23:45:29Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), M. De Pasquale (UCL-MSSL), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+484 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 100117A (trigger #382941)
(De Pasquale, et al., GCN Circ. 10336). The BAT ground-calculated position is
RA, Dec = 11.280, -1.586 deg which is
RA(J2000) = 00h 45m 07.1s
Dec(J2000) = -01d 35' 11.1"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 66%.
The mask-weighted light curve shows a single peak starting at T+0.0 and ending
at T+0.4 sec. T90 (15-350 keV) is 0.3 +- 0.05 sec (estimated error including
systematics).
The time-averaged spectrum from T-0.0 to T+0.3 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
0.88 +- 0.22. The fluence in the 15-150 keV band is 9.3 +- 1.3 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.35 sec in the 15-150 keV band
is 2.9 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/382941/BA/
GCN Circular 10339
Subject
GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
Date
2010-01-18T02:06:23Z (15 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, D. A. Perley, J. S. Bloom, B. E. Cobb, and A. N. Morgan (UC
Berkeley) report on behalf of a larger collaboration:
We have obtained pre-explosion images of the field of GRB100117A from the
Canada-France-Hawaii MegaCam archive. Images were obtained in the g', r',
and z' filters on 26 December 2005, and in the i' filter on 12 November
2007. Exposure times ranged from 240 s in g'-band to 500 s in i'-band.
Inside the candidate XRT afterglow localization (de Pasquale; GCN 10336),
we find four sources, with the following positions and R- and I-band
magnitudes (calibrated relative to several USNO-B1 sources in the field;
expected systematic uncertainty ~ 0.3 mag):
Source RA Dec (J2000.0) R I
----------------------------------------------------------------------
S1 00:45:04.82 -01:35:47.7 23.1 21.0
S2 00:45:04.78 -01:35:45.5 23.6 22.9
S3 00:45:04.70 -01:35:42.0 24.5 22.9
S4 00:45:04.53 -01:35:49.2 > 24.7 23.6
We have also obtained a single epoch of acquisition imaging in i'-band of
the field with GMOS on Gemini South beginning at 00:46 on 18 January 2010
(~ 4.7 hours after the burst). We detect only S1 in this image, at a
magnitude consistent with the value derived from the CFHT image.
Furthermore, given the uncertainty in our astrometry (~ 0.5" in each
coordinate), we believe it likely this is the same source identified by
Xu et al. (GCN 10337) at R = 22.5 +/- 0.5. We therefore have no evidence
that this source has varied.
Further observations are planned.
We wish to thank the Gemini Observatory staff, in particular Peter Pessev,
for assistance with these observations.
GCN Circular 10340
Subject
GRB 100117A: Magellan IMACS imaging
Date
2010-01-18T06:12:30Z (15 years ago)
From
Ryan Chornock at UC Berkeley <chornock@astro.berkeley.edu>
R. Chornock, E. Berger (Harvard), R. Williams, and D. Kelson (OCIW) report:
"We observed the location of the short GRB 100117A (GCN 10336) with
IMACS on the Magellan/Baade 6.5-m telescope starting on 2010 Jan
18.042 UT (3.9 hours after the burst). In a 1200 sec stacked R-band
image with a seeing of about 1" we detect the same four objects within the XRT
error circle (GCN 10336) found in archival CFHT images by Cenko et al. and
listed in GCN 10339. All four objects appear to be extended in our image,
indicating that one of them may represent the GRB host galaxy. No new sources
appear to be present within the XRT error circle, with a 3-sigma limiting
magnitude of approximately R=24.7."
GCN Circular 10341
Subject
GRB 100117A: Gemini-North upper limit
Date
2010-01-18T07:31:14Z (15 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara, D. B. Fox (PSU), E. Berger, R. Chornok (Harvard),
A. Fruchter, J. Graham (STScI) report on a larger collaboration:
"We observed the location of the short GRB 100117A (GCN 10336) with
GMOS on the Gemini-North 8-m telescope starting on 2010 Jan 18.208 UT
(7.9 hours after the burst). In a 2700 sec stacked r-band image with
a seeing of about 1" we detect the same four objects within the XRT
error circle (GCN 10336) found in archival CFHT images by Cenko et
al. and listed in GCN 10339 (see also GCN 10340). As in the
Magellan/IMACS image (GCN 10340) all four objects appear to be
extended in the Gemini-North/GMOS data, indicating that one of them
may represent the GRB host galaxy. No new sources appear to be
present within the XRT error circle, with a 3-sigma limiting magnitude
of approximately r=26.5."
GCN Circular 10342
Subject
GRB 100117A: Swift-XRT refined analysis
Date
2010-01-18T14:44:00Z (15 years ago)
From
Boris Sbarufatti at INAF-IASF-Pa <sbarufatti@ifc.inaf.it>
B. Sbarufatti, R. Margutti (INAF/OAB) and M. De Pasquale (UCL-MSSL)
report on behalf of the Swift-XRT team:
We have analysed 5.5 ks of XRT data for GRB 100117A (De Pasquale et
al. GCN Circ. 10336), from 69 s to 18.9 ks after the BAT trigger. The
data comprise 180 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode.
The best position is the SPER UVOT enhanced position: RA,Dec =
11.2690, -1.5949
(degrees) which is equivalent to:
RA (J2000) = 00 45 4.56
Dec (J2000) = -01 35 41.7
with an uncertainty of 2.4 arcsec (radius, 90% containment).
This location is 50.8 arcseconds from the BAT ground position, inside
the BAT
error circle.
After the initial flaring activity the light curve can be modeled with
a power-law decay with a decay index of alpha=3.5 (+/-0.2). The
afterglow is not detected after the first snapshot of data (ending 500
s after the trigger), with an upper limit of 5E-3 count/sec at ~12 ks
after the trigger
The spectrum formed from the WT mode data can be fitted with an
absorbed power-law with a photon spectral index of 1.6 (+/-0.13). The
best-fitting absorption column is 1.2 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 2.7 x 10^20 cm^-2 (Kalberla et al.
2005). The observed (unabsorbed) 0.3-10 keV flux is 4.14 (4.84) x
10^-10 erg cm^-2 s^-1.
The spectrum formed from the PC mode data can be fitted with an
absorbed power-law with a photon spectral index of 2.3 (-0.5+0.6). The
best-fitting absorption column is 1.1 (+1.3-0.9) x 10^21 cm^-2,
slightly in excess of the Galactic value of 2.7 x 10^20 cm^-2
(Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux is
2.40 (3.54) x 10^-12 erg cm^-2 s^-1.
The count-rate to flux conversion factor is 6.0E-11 erg cm^-2 count^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00382941
.
This circular is an official product of the Swift-XRT team.
GCN Circular 10343
Subject
GRB 100117A: Optical object inside the revised XRT error circle
Date
2010-01-18T16:23:10Z (15 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. Alexander Kann (TLS Tautenburg), D. Malesani (DARK/NBI), D. Xu (WIS,
DARK/NBI) report on behalf of a larger collaboration:
Using the improved XRT position (B. Sbarufatti et al. GCN 10342) for the
Swift short/hard GRB 100117A (M. de Pasquale et al., GCN 10336), we find
that the afterglow candidate reported from NOT observations (D. Xu et al.,
GCN 10337), which is probably identical to source "S1" from S. B. Cenko et
al. (GCN 10339), lies outside the error circle. We therefore consider it
unlikely that this object is related to the GRB, also considering the lack
of pronounced variability (S. B. Cenko et al. GCN 10339).
Of the four sources reported by S. B. Cenko et al. (GCN 10339) and
confirmed by R. Chornock et al. (GCN 10340) and A. Cucchiara et al. (GCN
10341), only source "S3" still lies within the new XRT error circle.
Source S3, which is extended according to the above reports, may be the
host galaxy of GRB 100117A, although lack of variability does not allow a
conclusive statement.
An additional image epoch to perform image subtraction is encouraged.
This message may be cited.
GCN Circular 10344
Subject
Swift/UVOT refined analysis of GRB100117A
Date
2010-01-18T18:00:20Z (15 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>
M. De Pasquale (MSSL/UCL), S. T. Holland (NASA/GSFC), S. Oates (MSSL)
report, on the behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 100117A
89s after the BAT trigger (De Pasquale et al., GCN 10336). We do not
detect any source in the UVOT-enhanced XRT error circle (Sbarufatti et
al. GCN 10342) in the initial finding chart in the white filter, nor
in the other filters. We do not detect the the S3 source of Cenko
et al. (GCN 10339). UVOT magnitude 3-sigma upper limits are
reported in the following table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
WHITE 89 238 147 > 20.4
WHITE 89 11957 1228 > 21.4
v 5589 17747 1082 > 19.8
b 557 6607 216 > 19.9
u 302 6402 442 > 19.9
uvw1 5999 18941 474 > 20.1
uvm2 5793 18652 1082 > 20.8
uvw2 5384 12757 978 > 20.9
No UVOT source has been found at the position of the NOT source
(Xu et al., GCN 10337) outside the XRT error circle.
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.02 mag
(Schlegel et al. 1998). All photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 10345
Subject
GRB 100117A: Fermi GBM detection
Date
2010-01-18T19:14:16Z (15 years ago)
From
Bill Paciesas at UAH <bill.paciesas@nasa.gov>
W. Paciesas (UAH) reports on behalf of the Fermi GBM Team:
"At 21:06:19.66 UT on 17 January 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100117A (trigger 285455181 / 100117879)
which was also detected by the Swift-BAT (De Pasquale et al. 2010, GCN
10336).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 86 degrees.
The GBM light curve consists of one pulse
with a duration (T90) of about 0.4 s.
The time-averaged spectrum from T0-0.128 s to T0+0.256 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -0.14 (+0.33 / -0.27) and
the cutoff energy, parameterized as Epeak, is 287 (+74 / -50) keV
(CSTAT 548 for 484 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(4.1 +/- 0.5 )E-07 erg/cm^2. The 0.256-sec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 6.1 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 10346
Subject
GRB 100117A: Gemini North spectroscopy
Date
2010-01-19T06:55:58Z (15 years ago)
From
Edo Berger at Harvard <eberger@cfa.harvard.edu>
E. Berger, R. Chornock (Harvard), A. Cucchiara, D. B. Fox (PSU)
report:
"Starting on 2010 Jan 19.22 UT we used the GMOS spectrograph on the
Gemini North 8-m telescope to obtain spectroscopic observations of
several extended objects (GCNs 10339, 10340, 10341) located inside and
near the revised XRT error circle (GCN 10342) of the short GRB 100117A
(GCN 10336). The slit was aligned so that it covered sources S1, S2,
and S3 (GCN 10339). Preliminary inspection of the combined 3000 sec
spectrum covering the wavelength range 4000-8000 A reveals that source
S1 is an M dwarf star. We detect continuum emission from sources S2
and S3 redward of about 5000 and 5600 A, respectively, but no clear
emission or absorption features are identified."
GCN Circular 10349
Subject
GRB 100117A: candidate optical afterglow
Date
2010-01-19T20:04:13Z (15 years ago)
From
Andrew Levan at U.of Leicester <A.J.Levan@warwick.ac.uk>
A.J. Levan (Warwick), J. Graham, A. Fruchter (STScI), N. Tanvir
(Leicester) A. Cucchiara, D. Fox (PSU), E. Berger, R. Chornock
(Harvard) report for a larger collaboration:
"We obtained a second epoch of Gemini North imaging of the short
duration GRB 100117A (De Pasquale et al. GCN 10336) beginning at
06:17 UT. A total of 2700s of observations were acquired in the
r-band.
Comparison with our first epoch of observations (Cucchiara et al.
GCN 10341) reveals that source S3 identifed by Cenko et al. (GCN
10339) has faded by 0.23 +/- 0.06 magnitudes in the timeframe between
the two epochs of observation (approximately 25 hours). This is
confirmed by image subtraction, which shows an offset from the centre
of S3 by ~0.6".
We suggest this is the afterglow of GRB 100117A. "