GRB 020127
GCN Circular 1306
Subject
GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
Date
2002-03-24T21:43:30Z (24 years ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
D.W. Fox, S.G. Djorgovski, and S.R. Kulkarni (Caltech) report on
behalf of a larger collaboration:
"We have imaged the area surrounding Source A14 of GCN 1249, a
candidate X-ray afterglow for the dark burst GRB020127, using the
Echelle Spectrograph and Imager (ESI) on the Keck-II telescope. In a
summed R-band image with 45 minutes total exposure in subarcsecond
seeing on March 13.3 (UT) we detect an extended object that we suggest
is the host galaxy of this GRB. The corresponding X-ray source A14
may in this case be identified as the likely X-ray afterglow of
GRB020127, which is therefore located at:
RA = 08 15 01.42, Dec = +36 46 33.9 (J2000)
with an uncertainty of roughly 1". A smoothed image of a portion of
the ESI field may be found at
http://www.astro.caltech.edu/~derekfox/grb020127/ESI_Rsum.gif
In light of this proposed identification, we suggest as well that the
coincident weak radio source reported in GCN 1250 was the radio
afterglow of this GRB."
GCN Circular 1257
Subject
GRB020127: Further VLA Observations of Possible Counterparts
Date
2002-02-22T23:53:21Z (24 years ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Derek W. Fox and Edo Berger (Caltech), with Dale A. Frail
(Caltech/NRAO), report on behalf of the Caltech-NRAO-CARA GRB
collaboration:
"On Feb 16.2 UT and Feb 22.0 UT we re-observed the position of Source
A14 of GCN 1249 with the VLA. Three-sigma upper limits on the flux
density of any 8.5 GHz source on these two dates are 110 uJy and 150
uJy, respectively. In particular, the previously identified 157 +/-
43 uJy radio source at (J2000) RA 08:15:01.4183(2), Dec
+36:46:33.43(3) (GCN 1250) is not detected at either epoch. Without a
confirming detection of this source, we cannot exclude the possibility
that the original Feb 14.2 UT detection was spurious.
On Feb 22.0 UT we also observed the regions surrounding Sources A45
and A7 of GCN 1249. Three-sigma upper limits on the 8.5 GHz flux
density of any radio sources on this date are 150 uJy for each of
these regions."
GCN Circular 1250
Subject
GRB020127: Palomar and VLA Observations of Possible Counterparts
Date
2002-02-15T04:25:34Z (24 years ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Derek W. Fox (Caltech) and Dale A. Frail (Caltech/NRAO) report on
behalf of a larger collaboration:
"On Feb 4 UT (g' band) and Feb 6 UT (r' band) we observed the HETE-IPN
localization region of GRB020127 (GCN 1232) with the Large Format
Camera on the Hale Telescope on Mt. Palomar. Reduction of images
covering the full localization region excludes the presence of any
optical counterparts to the three X-ray sources A14, A45, and A7 of
GCN 1249, at the respective epochs of these images, to limiting
magnitudes of g'~23 and r'~23.3."
"Separately, on Feb 14.2 UT we observed the region surrounding Source
A14 of GCN 1249 with the VLA. Within the roughly one-arcsecond
Chandra localization we find a weak radio source with an 8.5 GHz flux
density of 157 +/- 43 uJy located at (J2000) RA 08:15:01.4183(2), Dec
+36:46:33.43(3). Follow-up observations are underway to confirm this
source detection."
GCN Circular 1249
Subject
GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
Date
2002-02-15T04:09:29Z (24 years ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Derek W. Fox (Caltech) reports on behalf of the Caltech-NRAO-CARA GRB
collaboration:
"We have made a comprehensive analysis of the data from two 10-ks
Chandra ACIS-I observations of the HETE-IPN localization region for
GRB020127 (HETE 1902; GCNs 1229, 1232, 1241). The full source
catalogs for these observations contain 48 and 50 sources,
respectively; approximately four sources in each epoch are anticipated
to be spurious detections. We identify three possible counterparts
based on their fading behavior between the Chandra observations (which
began at Jan 31.95 UT and Feb 11.46 UT, respectively) and the absence
of a bright stellar or galactic counterpart in archival images:
Source RA Dec Nsig F1 F2
===================================================================
A14=B16 08 15 01.42(1) +36 46 33.9(1) 13.6 84(16) 19(6)
A45 08 15 42.78(7) +36 47 00.2(10) 5.7 28(7) <14
A7 08 14 47.82(3) +36 49 35.4(3) 4.1 13(4) <14
===================================================================
Numbers in parentheses indicate the uncertainty in the preceding
digits, and positional uncertainties do not account for the overall
Chandra aspect uncertainty of roughly one arcsec. Nsig is the nominal
(single-trial) significance of the source detection as reported by
wavdetect. F1 and F2 are source count rates for the first and second
epochs, respectively, in units of photons cm^(-2) ks^(-1) (0.3-7 keV);
upper limits are roughly two-sigma. Source A14 is detected in the
second epoch as source B16, while neither source A45 nor source A7 are
detected in the second epoch.
We note explicitly that the sources above are not the only sources
within the HETE-IPN localization to show variability between the two
epochs; however, they are the only sources, not associated with bright
stellar or galactic counterparts, that show convincing evidence of a
decline in flux. The full source catalog for the two observations is
available at the following URL:
http://www.astro.caltech.edu/~derekfox/grb020127/chandra.html
Given the strength of source A14 (=B16) in the first observation, and
its observed fading behavior -- which is consistent with a t^(-1.2)
power-law referred to the epoch of GRB020127 -- we consider source A14
to be the most likely candidate for the afterglow of GRB020127."
GCN Circular 1246
Subject
GRB020127, WSRT radio observations
Date
2002-02-06T16:40:00Z (24 years ago)
From
Evert Rol at U.Amsterdam <evert@astro.uva.nl>
GRB020127, WSRT radio observations
Evert Rol, Paul Vreeswijk, Lex Kaper, (University of Amsterdam), Richard
Strom (ASTRON, UoA) report, on behalf of a larger collaboration:
"We have performed observations of the HETE error circle of GRB020127
(Ricker et al, GCN 1229) with the Westerbork Synthesis Radio
Telescope. We observed at 2.3 GHz at two epochs, Jan 28.72-29.22 and
Feb 3.71-4.21, and at 1.4 GHz at one epoch, Jan 28.72-29.22.
At 2.3 GHz, we detect six sources within the combined HETE/IPN error
circle (Hurley et al., GCN 1232) to a limit of 0.62 mJy (3 sigma). No
sources show variability between the two observations. The 1.4 GHz
observation also contains these six sources, none of which has a
positive spectral index.
We do not find any radio counterparts to the Chandra X-ray sources
(Fox, GCN 1241)."
GCN Circular 1245
Subject
GRB020127 Optical Observations
Date
2002-02-06T02:00:48Z (24 years ago)
From
Brian Lee at Fermilab <bclee@fnal.gov>
B. C. Lee, D. Q. Lamb, R. J. McMillan, D. G. York and D. E. Vanden Berk,
on behalf of the SDSS GRB team, report:
The field of GRB020127 (= H1902) (Ricker et al., GCN 1229) was
observed by the SDSS in two interlaced runs on 2001 December 18.34 and
19.30 UTC in the normal course of SDSS operations. We have examined
the SDSS u* g* r* i* z* images in the vicinity of the eleven probable
X-ray sources seen in the first Chandra follow-up observation (Fox,
GCN 1241