GRB 011030
GCN Circular 1269
Subject
XRF/GRB 011030 Images
Date
2002-03-12T20:37:27Z (24 years ago)
From
Andrew S. Fruchter at STScI <fruchter@stsci.edu>
A. Fruchter (STScI) reports:
Images of the probable host galaxy of XRF/GRB 011030, described
in GCN 1268, can be found at
http://www.stsci.edu/~fruchter/GRB/011030
GCN Circular 1268
Subject
XRF/GRB 011030: Detection of the Probable Host Galaxy
Date
2002-03-12T20:03:45Z (24 years ago)
From
Andrew S. Fruchter at STScI <fruchter@stsci.edu>
A. Fruchter (STScI), S. Pattel (MSFC), C. Kouveliotou (MSFC), J.
Rhoads (STscI), S. Holland (Notre Dame), I. Burud (STScI) and R. Wijers
(Stony Brook) report for the larger GOSH (Grb Optical Studies with Hst)
collaboration:
A field containing the reported X-ray (GCN 1143) and radio (GCN 1136)
positions of XRF/GRB 011030 (GCN 1118) was observed with HST on 12
December 2001 using the STIS CCD camera both in open mode (50CCD) and
with a red-pass filter (LP). Due to the low-galactic latitute (b=20.6)
of this field, the estimated foreground extintion is Av=1.2 (Schlegel,
Finkbeiner, Davis 1999). Nevertheless, a 26th magnitude galaxy is
found to be coincident with both the X-ray and radio positions (within
the reported ~1" errors of both).
With the public release of the second epoch of Chandra observations
(taken on 29 November 2001), we have been able to determine that the
X-ray source fell between the two Chandra epochs approximately as
t^{-2} (using the time of the XRF/GRB as the zero-point), thus confirming
the association of this source with the XRF/GRB.
We have therefore attempted to refine the Chandra error circle. We
aligned the first, deeper (9-November) Chandra observation with
wide-field R band images obtained on the 1 and 3 November on the WIYN
telescope using six point sources which are bright in both images. We
find an r.m.s. positional offset between sources in the two images of
~0."18. As the XRF/GRB is brighter in the Chandra image than any source used
in the fit (though not visible in the WIYN image), we estimate that the
error in transforming its position to the optical field should be no larger
than 0."18, one sigma. We have also been able to place the WIYN image on
the J2000 coordinate system to an accuracy of ~0."1, using both Naval
Observatory and Tycho standards.
We find that the 0."18 Chandra error circle overlaps the somewhat
bluer, eastern end of the small irregular galaxy noted above. The galaxy
is approximately 0."5 across, and has a total magnitude of V~26.2, or
approximately V=25, after removal of the estimated foreground extinction.
This is comparable to the peak of the distribution of XRF/GRB host
magnitudes (Hogg and Fruchter 1999). The color of the galaxy (again
after removal of the foreground extinction) is quite blue (consistent
with a power-law of nu^{-0.5}), suggesting both a relatively young
stellar population and that the galaxy has a redshift, z < 3. XRF/GRB
011030 thus appears to be similar to GRBs in its probable redshift and
in its association with a faint, blue galaxy; this in turn suggests that
XRFs are not a radically different class of object, but are very soft GRBs.
GCN Circular 1146
Subject
GRB 011030: TNG K-band observation
Date
2001-11-21T17:03:56Z (24 years ago)
From
Angelo Antonelli at Obs. Astro. di Roma <angelo@coma.mporzio.astro.it>
L.A. Antonelli, (INAF, Astr. Obs. Rome), F. Mannucci (CAISMI, CNR,
Firenze), E. Pian (INAF, Astr. Obs. Trieste), V. Testa, A. Di Paola,
L. Stella (INAF, Astr. Obs. Rome), I. Burud, A. Fruchter, J. Rhoads
(STScI), N. Masetti, E. Palazzi, F. Frontera (ITeSRE, CNR, Bologna),
S. Covino (INAF, Astr. Obs. Brera, Milan), D. Lazzati (IoA, Cambridge),
L. Piro (IAS, CNR, Rome), J. Licandro, F. Ghinassi (TNG), S. Klose
(TLS, Tautenburg), on behalf of a larger collaboration, report:
"We imaged the field of XRF011030 (GCN 1118) with TNG equipped with the
near-IR camera NICS and K filter on Nov 10, 20:22 - 22:48 UT. During
the observation the seeing was 1.5". The AS36 photometric standard was
also observed and used for magnitude calibration.
No source is detected at the position of the radio transient reported
by Taylor et al. (GCN 1136) nor in the Chandra error box of the X-ray
source detected by Harrison et al. (GCN 1143) to a 5-sigma limiting
magnitude of K = 20.1.
This message may be cited."
GCN Circular 1144
Subject
GRB011030, optical observation
Date
2001-11-19T14:22:21Z (24 years ago)
From
Rene Hudec at AIO <rhudec@asu.cas.cz>
R. Hudec (Astronomical Institute Ondrejov), J. Polcar (Astronomical
Institute Ondrejov and Masaryk University Brno), M. Tichy and J. Ticha
(Klet Observatory) report:
The whole error box of GRB011030 was imaged with the Klet Observatory
0.57-meter f/5.2 telescope (+CCD camera SBIG ST-8) on 2001 Oct 31, 17:24
to 17:39 UT (10 exposures 60 sec each). No new and/or fading object has
been detected down to limiting magnitude of 19.5 (unfiltered), error
0.5 mag.
This message can be cited.
GCN Circular 1142
Subject
GRB 011030: K-band observations
Date
2001-11-15T12:27:51Z (24 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
S. Klose, B. Stecklum, A. Zeh (Thueringer Landessternwarte Tautenburg),
O. Fischer (Universitaets-Sternwarte Jena),
U. Thiele (Calar Alto observatory, Spain),
R. Neuhaeuser, N. Huelamo,
(Max-Planck-Institut fuer Extraterrestrische Physik, Garching),
J. Greiner (AIP Potsdam),
A. Castro-Tirado (LAEFF-INTA, Madrid, and IAA-CSIC, Granada),
N. Masetti, E. Palazzi (ITeSRE, CNR, Bologna),
E. Pian (Oss. Astron. Trieste),
report:
The error circle of the X-ray transient 011030 (Gandolfi et al., GCN
#1118) was imaged with the Calar Alto 3.5-m telescope on Oct. 30,
18:32 UT - 19:33 UT (i.e., about 12 hours after the burst trigger)
using the near-infrared camera Omega Cass in the polarimetric
mode. The limiting magnitude in the central part of the K'-band image
(mosaic) is about K'=19.5 after adding all frames taken at different
position angles of the wire-grid polarizer. Since standard stars are
not yet available we estimate the error of this magnitude limit to +/-
0.5 mag. The combined image covers about 90% of the revised error
circle (in 't Zand et al., GCN #1123).
At the position of the radio transient reported by Taylor et al. (GCN
#1136) no source is detected (see also Hammell et al., #GCN 1126).
We do not detect the I-band source reported by Halpern et al. (GCN
#1139).
This message is quotable.
GCN Circular 1141
Subject
GRB011030: Z-band observations
Date
2001-11-14T23:12:28Z (24 years ago)
From
Andrew S. Fruchter at STScI <fruchter@stsci.edu>
M. Brown, A. Dey (NOAO), A. Fruchter and J. Rhoads (STScI) report for
a larger collaboration:
The field of the radio transient (Taylor et al., GCN 1136) potentially
associated with GRB011030 was imaged at the KPNO 4-m using the
Multi-Aperture Red Spectrometer (MARS) through an RG830 (approximately
z-band) filter from 1:55 to 2:50 12 NOV 01 UT. Due to significant
overhead associated with the instrument, the total exposure time was
600 seconds; the seeing was approximately 1."5. No source was detected
at the position of the radio transient, or that of the potential I-band
object nearby reported by Halpern et al. (GCN 1139), down to a limiting
(Vega) magnitude of 22.5 (5-sigma).
GCN Circular 1140
Subject
GRB 011030 R band observations
Date
2001-11-10T02:36:39Z (24 years ago)
From
James Rhoads at STScI <rhoads@stsci.edu>
James E. Rhoads, Ingunn Burud, Andrew Fruchter, Chryssa Kouveliotou,
and Michael Wood-Vasey report on behalf of a larger collaboration:
We observed the error circle of GRB 011030 with the 3.5m WIYN telescope
and mini-mosaic imager on the nights of UT 011101, 011102, and 011103,
obtaining five 600 second images in the R band each night.
We find no source at the location of the new radio source reported by
Taylor et al (GCNC 1136). If we adopt the R band zero point used by
Bloom et al (GCNC 1137), the corresponding 5 sigma upper limits are
R=23.61 (011101) and R=23.28 (011103).
In addition, we performed a seeing-matched image subtraction on the
011101 and 011103 data. The difference image shows no significantly
variable sources. The estimated photometric noise level in the
difference image (for a 1 arcsec radius aperture) is 0.5 microJansky
(1 sigma), corresponding to R=24.5 (1 sigma) or R=22.7 (5 sigma).
Further analysis of existing data is underway, and at least one
additional observation is planned.
We thank Doug Williams and Di Harmer for their help in these observations.
GCN Circular 1139
Subject
GRB 011030 I-band Observation
Date
2001-11-09T19:29:34Z (24 years ago)
From
Jules Halpern at Columbia U. <jules@astro.columbia.edu>
J. P. Halpern, N. Mirabal (Columbia), C. Burke, D. L. DePoy (Ohio State), &
S. Gaudi (IAS), report on behalf of the MDM Observatory GRB follow-up team:
"Using the MDM 2.4m, we reobserved this location in the I band on Nov. 9.23 UT.
In two 8 minute exposures in seeing of 1.2 arcseconds, there is a possible
detection at the 2 sigma level of an object at position (J2000) 20:43:31.94,
+77:17:19.0, which is 1.2 arcseconds west of the position reported for the new
radio source that appeared on Nov 8.80 (Taylor et al. GCN #1136). Assuming
for a calibration that the faintest objects on the POSS-II IVN plates have
I=19.5, this possible counterpart would have I=22.5. Given the marginal
level of this detection and its absence on previous images of comparable
depth on Nov. 1, confirmation would be required. Alternatively, this may
be considered an upper limit to the optical brightness of the radio source.
The new image is posted at
http://www.astro.columbia.edu/~jules/grb/011030
This message may be cited."
GCN Circular 1138
Subject
The X-ray Flash 011030 ('GRB 011030')
Date
2001-11-09T16:25:10Z (24 years ago)
From
Jean int Zand at SRON <jeanz@sron.nl>
J. Heise (SRON, Utrecht), J.J.M. in 't Zand (Utrecht Univ. and SRON),
S.R. Kulkarni (Caltech), and E. Costa (CNR, IAS, Rome) report:
"We have carried out further investigations of SAX J2043.6+7717, the X-ray
rich transient of 30 October, 2001 discovered by BeppoSAX-WFC (GCN 1118).
The flash peaks at 0.26 Crab units (2-28 keV), while activity is detected for
about 1400 s (but we note that the observations started about 100 s before
the first activity from this source was detected). The spectrum is
characterized by a power law with a photon index of -1.9 +/- 0.1. A black
body fit is inconsistent with the data at 99.97% confidence. The 2-28 keV
fluence is estimated at 9E-7 erg/cm2. For X-ray light curve and spectrum,
we refer to http://wfc.sron.nl/flash/
What could SAX J2043.6+7717 be?
By several accounts, SAX J2043.6+7717 does not appear to be a traditional
GRB. First, the absence of detection of the X-ray transient in the Gamma-Ray
Burst Monitor on BeppoSAX means that the peak energy of the transient must be
lower than ~40 keV. In contrast, GRBs are distinguished by peaking in the 50
to 500 keV range. Second, GRBs with such long duration are rare, e.g. the
longest T90 listed in the 4th BATSE catalog (Paciesas et al. 2000, ApJS, 122,
465) out of 1234 bursts is 674 s (trigger 3458) and in general have strong
pulses. In contrast, SAX J2043.6+7717 lasted more than a thousand seconds long.
The second possibility, especially given the galactic latitude of
SAX J2043.6+7717 (b=+20.7 degrees), may argue for this source to be a Galactic
transient. However, the X-ray spectrum rules out SAX J2043.6+7717 being a type
I X-ray burst. This then leaves us with the possibility that SAX J2043.6+7717
is a Fast X-ray Transient (FXT; e.g., Grindlay 1999, ApJ, 510, 710). However,
FXTs usually last longer than an hour. More importantly, FXTs have been
identified with relatively bright quiescent optical/IR counterparts e.g.
RS CVns, nearby dMe stars, super flares from pre-main sequence stars and
black hole transients. However, as noted in GCN 1137, there is no visible
optical counterpart to the radio source nor was a bright optical or IR
transient (GCN 1127) seen following the detection of the X-ray transient.
We conclude that most likely SAX J2043.6+7717 is a member of the newly
recognized class of X-ray flashes (Heise et al. 2001, in Proc. 'Gamma-Ray
Burst in the Afterglow Era', Rome, Oct. 17-20, 2000, in press).
Given that we know little about such events (with the 011030 flash possibly
being the first event localized to arcsecond accuracy; see GCN 1136