XRF 040701
GCN Circular 2824
Subject
HST Observations: XRF 040701 and 040812
Date
2004-10-19T16:07:38Z (21 years ago)
Edited On
2025-09-09T18:37:21Z (a month ago)
From
Shri Kulkarni at Caltech <srk@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
S. Kulkarni, A. Soderberg and D. Fox report on behalf of the
Caltech/Carnegie/NRAO collaboration:
"As part of our large HST program on GRBs and XRFs, we have used ACS to
observe the fields of XRF 040701 and XRF 040812. Observations were
taken in the F625W (r) and F775W (i) filters 39 and 60 days after the
burst (XRF040701) and 32 and 54 days after the burst (XRF040812).
Comparison of the two epochs for each XRF does not reveal a variable
source within the 1-arcsec position of the putative Chandra X-ray
afterglow candidates (GCNs 2630 and 2655 for XRFs 040701 and 040812,
respectively). Our 3-sigma limits are the following:
XRF Filter Limit:
==============================================
040701 F625W 27.5
F775W 27.0
040812 F625W 27.5
F775W 27.0
GCN Circular 2638
Subject
XRF040701: Optical Observations at ESO
Date
2004-08-09T18:15:33Z (21 years ago)
Edited On
2025-09-09T18:36:39Z (a month ago)
From
Elena Pian at IASF,CNR,Bologna <pian@bo.iasf.cnr.it>
Edited By
courey.elliott@gmail.com
E. Pian, J. Fynbo , U. G. Joergensen, A. Levan, N. Masetti, E. Palazzi,
F. Patat, E. Rol, J. Hjorth, B. Lindgren Jensen, P. Mazzali, C.
Kouveliotou, K. Nomoto, E. Cappellaro, on behalf of a larger
collaboration, report:
The field of source CXOU J204816.1-401108 (Fox et al. GCN 2626), detected
in the error box of XRF040701 (Barraud et al., GCN 2620), was imaged with
the ESO Danish 1.5m telescope at La Silla on 2004 Jul
03,15,16,17,19,23,24, Aug 4,5, and with the VLT and FORS1 on 2004 Jul
23.16, 23.33, 30.35 UT in the R band. The VLT imaging of Jul 23 was done
under excellent seeing conditions (0.6").
Both R-band photometry and PSF-matched image subtraction of the galaxy at z
= 0.2146 underlying CXOU J204816.1-401108 (Kelson et al. GCN 2627) rule
out flux variations larger than a few hundredths of a magnitude.
Considering that we determine a lower limit of R~17.9 for the galaxy
brightness, an event similar to supernova 1998bw would produce an observed
variation of about 6% from explosion to maximum light. Therefore, our data
appear marginally to exclude a supernova similar to 1998bw (see also
Berger et al. GCN 2631), but not a weaker one, like SN2002ap or SN1994I.
A 2hr VLT+FORS1+300V spectrum of the galaxy taken on Jul 23 does not
reveal conspicuous supernova features. The 2 galaxies located at ~4" West
and ~6" South of the galaxy underlying CXOU J204816.1-401108 have
redshifts 0.215 and 0.17, respectively.
This message can be cited.
GCN Circular 2631
Subject
XRF 040701 - optical observations of the decaying Chandra source
Date
2004-07-23T05:15:04Z (21 years ago)
Edited On
2025-09-09T18:36:38Z (a month ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
E. Berger (Caltech/Carnegie), A. Gal-Yam, D.B. Fox (Caltech), I.
Thompson (Carnegie), B. Schmidt, R. McNaught and B. Peterson (MSO,ANU)
report on behalf of a larger collaboration:
"We used the Du Pont 2.5-m Telescope + CCD at the Las Campanas
Observatory on July 16.29, 17.29, 18.28 and 19.25 UT to image an 8.8'
x 8.8' field centered on the position of Chandra X-ray source CXO-2
(GCN 2626) -- suggested by Fox (GCN 2630) as a possible counterpart of
XRF 040701 (GCN 2620) and associated with a galaxy at a redshift
z=0.2146 (GCN 2627). All observations were performed in the R band in
good seeing and weather conditions with exposure times of 20 minutes
on the first three nights and 25 minutes on July 19. In addition, we
obtained an R-band image of the field with the 40-in telescope at
Siding Springs Observatory on July 14.
Using PSF-matched image subtraction (with the CPM/DDA algorithm, as in
Gal-Yam et al. 2004, ApJ, 609, L59), we detect no sign of
variability. If this is in fact the counterpart of XRF 040701, and
assuming that any optical emission during this period would be
dominated by a SN 1998bw-like event, associated with this XRF, then
the lack of variability may not be surprising. Owing to its broad
peak, SN 1998bw varied by only 0.1 mag in the rest-frame V-band during
the same time. It is also possible that a SN associated with XRF
040701 is extinguished by dust and/or is fainter than SN1998bw."
GCN Circular 2630
Subject
XRF040701: Second-Epoch Chandra Observations
Date
2004-07-22T00:23:59Z (21 years ago)
Edited On
2025-09-09T18:36:36Z (a month ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
D.B. Fox (Caltech) reports on behalf of a larger collaboration:
"We have observed the HETE localization region for XRF040701 (Barraud
et al., GCN 2620) with the Chandra X-ray Observatory + ACIS for 20.4
ksec beginning at 01:07 UT on July 18, 2004. The observation aimpoint
and dither pattern are identical to that of our first-epoch
observation (Fox, GCN 2626); however, a change in the roll angle has
resulted in a slightly different exposure pattern due to the chip gaps
of the ACIS-I array. A comprehensive "wavdetect" analysis provides
the following second-epoch fluxes for sources from the catalog of our
initial observation:
Ep #1 Ep #2 Variability
# RA Dec Flux Unc Flux Unc % Sigma
==================================================================
1 20 47 20.696 -40 19 41.52 25.6 3.2 20.5 3.0 80 -1.6
2 20 48 16.097 -40 11 08.83 11.1 2.1 6.4 1.7 58 -2.2
3 20 47 46.602 -40 13 57.15 9.0 2.0 9.4 2.3 105 0.2
4 20 47 23.970 -40 10 56.07 8.8 2.2 12.2 2.3 138 1.5
5 20 47 19.056 -40 12 34.33 8.5 1.8 7.8 1.9 92 -0.4
6 20 48 05.696 -40 18 23.01 8.1 1.8 7.5 1.8 93 -0.3
7 20 47 51.810 -40 19 36.90 8.0 1.7 5.1 1.5 63 -1.7
8 20 47 06.231 -40 14 45.66 7.8 1.8 7.7 2.0 99 -0.0
9 20 48 05.337 -40 12 33.74 6.1 1.5 7.2 1.7 118 0.8
10 20 47 36.158 -40 16 23.76 6.0 1.4 5.5 1.4 92 -0.3
11 20 47 39.249 -40 17 48.32 5.5 1.4 6.2 1.6 112 0.5
12 20 48 09.981 -40 07 21.19 5.4 1.6 3.8 1.4 71 -1.0
13 20 47 40.281 -40 12 25.99 4.5 1.3 4.8 1.8 107 0.2
14 20 48 23.282 -40 18 01.06 4.3 1.7 4.5 1.6 105 0.1
15 20 47 33.118 -40 14 47.48 4.1 1.2 6.0 1.6 146 1.6
16 20 47 12.288 -40 11 12.49 4.1 1.3 4.4 1.5 106 0.2
17 20 48 10.054 -40 19 32.71 4.1 1.3 3.4 1.3 83 -0.5
18 20 47 51.377 -40 06 03.64 3.9 1.4 1.6 1.0 41 -1.7
19 20 47 56.453 -40 07 15.01 3.9 1.3 2.5 1.2 65 -1.0
20 20 47 55.713 -40 13 47.56 3.8 1.1 4.0 1.3 104 0.1
21 20 47 47.349 -40 15 16.97 3.7 1.1 4.2 1.3 112 0.4
22 20 47 34.678 -40 10 42.16 3.7 1.1 1.9 0.9 53 -1.6
23 20 48 09.739 -40 10 05.74 3.6 1.2 3.4 1.2 95 -0.1
==================================================================
24 20 48 16.866 -40 11 46.55 3.0 1.1 4.1 1.2 135 0.9
25 20 47 49.854 -40 06 27.14 2.8 1.1 2.7 1.2 96 -0.1
26 20 48 10.259 -40 12 56.78 2.7 1.0 3.2 1.2 121 0.5
27 20 47 36.341 -40 14 26.55 2.6 1.0 3.6 1.2 135 1.0
28 20 47 48.624 -40 08 28.52 2.5 1.0 1.6 0.9 64 -0.9
29 20 47 17.085 -40 08 25.65 2.3 1.0 1.5 0.0 66 -0.7
30 20 48 03.514 -40 10 28.77 2.0 0.9 3.7 1.4 180 1.7
31 20 48 03.294 -40 10 47.68 1.8 0.9 <1.5 - <82 <-0.4
32 20 48 08.121 -40 18 42.44 1.8 0.9 2.0 1.0 108 0.2
33 20 47 48.309 -40 15 04.50 1.8 0.8 <1.5 - <83 <-0.4
34 20 47 48.316 -40 16 00.24 1.8 0.8 1.6 0.8 89 -0.3
35 20 47 47.796 -40 15 12.32 1.7 0.6 <1.5 - 88 -0.4
36 20 47 58.094 -40 17 35.49 1.4 0.8 <1.5 - <103 <0.1
37 20 47 28.350 -40 14 29.01 1.4 0.8 <1.5 - <107 <0.1
==================================================================
As in the original catalog, fluxes here are in approximate units of
1E-06 photons/cm^2/s. Given a flux F1 and flux uncertainty U1 at the
first epoch, and flux (uncertainty) F2 (U2) at the second epoch, we
calculate the "Variability %" as 100*F2/F1, and the "Variability
Sigma" as (F2-F1)/U1.
Our two Chandra observations take place 7.9 and 16.6 days after the
burst, respectively, and we therefore expect a flux decay of
approximately 53% for an afterglow power-law decay with index alpha ~
-1. The sources showing the strongest evidence for a decrease in flux
of this magnitude are (in decreasing order of confidence) sources #2,
#7, and #18. Source #18 is 13-arcsec outside the HETE localization.
Given the brightness of Source #2, its fading behavior, and its
association with a z=0.2146 galaxy (Kelson et al., GCN 2627), this
source is our preferred candidate of these three."
GCN Circular 2628
Subject
XRF040701: VLA Observations
Date
2004-07-13T22:07:14Z (21 years ago)
Edited On
2025-09-09T18:36:35Z (a month ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
P.B. Cameron and D.B. Fox (Caltech) with D.A. Frail (NRAO) report on
behalf of a larger collaboration:
"We have made several targeted observations within and near the
localization region for XRF040701 (Barraud et al., GCN 2620) with the
VLA in D-configuration, on July 12, 2004, from 08:19 to 09:48:49 UT.
The chief aim was to provide full coverage of the brighter part of the
Chandra source catalog (Fox, GCN 2626); however, the resulting
pointings provide coverage of approximately 75% of the region at
X-band (8.4 GHz) and approximately 10% of the region in C-band (4.9
GHz).
We detect five sources within our coverage area, one of which is an
NRAO VLA Sky Survey (NVSS) 1.4-GHz source, and none of which are
coincident with Chandra sources. In addition, we have marginal (~2
sigma) detections at the positions of three Chandra sources. The
following table reports the VLA source positions, frequency of
detection, and flux in mJy, with uncertainties in the final digits
given in parentheses. In addition, we note whether the particular
source was detected in the NVSS (Y/N), which has an average RMS noise
level of 0.45 mJy/beam at 1.4 GHz but technically is only complete to
a declination of -40 degrees.
VLA# RA Dec Freq Flux NVSS?
==========================================================
1 20 47 37.968 -40 15 44.65 8.35 1.01(10) N
2 20 47 07.707 -40 15 48.02 8.35 0.76(09) Y
3 20 47 35.965 -40 13 34.72 8.35 0.48(10) N
4 20 47 52.542 -40 12 36.45 8.35 0.47(10) N
5 20 47 29.041 -40 11 28.94 8.35 0.32(09) N
==========================================================
We note that VLA source #1 is coincident with a bright star-like
source and USNO B-1.0 object from the DSS.
The following table reports our marginal ~2-sigma detections at the
positions of sources from the Chandra catalog. We give the Chandra ID
number and name from Fox (GCN 2626), the frequency of observation, and
the estimated flux in mJy with uncertainties in the final digits given
in parentheses. In addition, we indicate whether the source has a
counterpart in the DSS (Y/N).
Chandra# Name Freq Flux DSS?
===========================================================
2 CXOU J204816.1-401108 8.35 0.22(10) Y
16 CXOU J204712.3-401112 8.35 0.19(09) N
25 CXOU J204749.9-400627 8.35 0.23(10) Y
===========================================================
Chandra source #2, which is associated with a z=0.2146 emission-line
galaxy (Kelson et al., GCN 2627) has a marginal detection in X-band
but not C-band."
GCN Circular 2627
Subject
XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
Date
2004-07-13T07:35:50Z (21 years ago)
Edited On
2025-09-09T18:36:33Z (a month ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
D.D. Kelson and K. Koviak (Carnegie), with E. Berger and D.B. Fox
(Caltech), report on behalf of a larger collaboration:
"We have observed the DSS-resolved galaxy associated with
CXOU J204816.1-401108, Source #2 from the catalog of Fox (GCN 2626),
which is potentially associated with XRF040701 (Barraud et al., GCN
2620), with the Magellan Baade 6.5-m telescope + IMACS spectrograph.
We find the spectrum of this galaxy to be rich in emission lines
including Hbeta4861A, [OIII]4959A,5007A, Halpha6563A, [NII]6548A,6583A,
and [SII]6717,6731. The redshift is z=0.2146."
GCN Circular 2626
Subject
XRF040701: First-Epoch Chandra Observations
Date
2004-07-12T17:09:09Z (21 years ago)
Edited On
2025-09-09T18:36:32Z (a month ago)
From
Derek Fox at CIT <derekfox@astro.caltech.edu>
Edited By
courey.elliott@gmail.com
D.B. Fox (Caltech) reports on behalf of a larger collaboration:
"We have observed the HETE localization region for XRF040701 (Barraud
et al., GCN 2620) with the Chandra X-ray Observatory + ACIS for 22.3
ksec beginning at 07:35 UT on July 9, 2004. The observation aimpoint
and dither pattern provide coverage of the full 8'-radius error
circle, with some decrease in exposure over the chip gaps of the
ACIS-I array. A comprehensive "wavdetect" analysis provides the
following catalog of sources detected with >3-sigma confidence in or
near (<15") the HETE localization region (coordinates are J2000):
# Name RA Dec Flux DSS?
==================================================================
1 CXOU J204720.7-401941 20 47 20.696 -40 19 41.52 25.6
2 CXOU J204816.1-401108 20 48 16.097 -40 11 08.83 11.1 Y*
3 CXOU J204746.6-401357 20 47 46.602 -40 13 57.15 9.0
4 CXOU J204724.0-401056 20 47 23.970 -40 10 56.07 8.8 Y
5 CXOU J204719.1-401234 20 47 19.056 -40 12 34.33 8.5
6 CXOU J204805.7-401823 20 48 05.696 -40 18 23.01 8.1
7 CXOU J204751.8-401936 20 47 51.810 -40 19 36.90 8.0
8 CXOU J204706.2-401445 20 47 06.231 -40 14 45.66 7.7
9 CXOU J204805.3-401233 20 48 05.337 -40 12 33.74 6.1
10 CXOU J204736.2-401623 20 47 36.158 -40 16 23.76 6.0 Y
11 CXOU J204739.2-401748 20 47 39.249 -40 17 48.32 5.5 Y
12 CXOU J204810.0-400721 20 48 09.981 -40 07 21.19 5.4
13 CXOU J204740.3-401225 20 47 40.281 -40 12 25.99 4.5
14 CXOU J204823.3-401801 20 48 23.282 -40 18 01.06 4.3
15 CXOU J204733.1-401447 20 47 33.118 -40 14 47.48 4.1
16 CXOU J204712.3-401112 20 47 12.288 -40 11 12.49 4.1
17 CXOU J204810.1-401932 20 48 10.054 -40 19 32.71 4.1
18 CXOU J204751.4-400603 20 47 51.377 -40 06 03.64 3.9
19 CXOU J204756.5-400715 20 47 56.453 -40 07 15.01 3.9
20 CXOU J204755.7-401347 20 47 55.713 -40 13 47.56 3.8 Y
21 CXOU J204747.3-401516 20 47 47.349 -40 15 16.97 3.7 Y
22 CXOU J204734.7-401042 20 47 34.678 -40 10 42.16 3.7
23 CXOU J204809.7-401005 20 48 9.739 -40 10 05.74 3.6
==================================================================
24 CXOU J204816.9-401146 20 48 16.866 -40 11 46.55 3.0
25 CXOU J204749.9-40 627 20 47 49.854 -40 06 27.14 2.8 Y
26 CXOU J204810.3-401256 20 48 10.259 -40 12 56.78 2.7
27 CXOU J204736.3-401426 20 47 36.341 -40 14 26.55 2.6
28 CXOU J204748.6-40 828 20 47 48.624 -40 08 28.52 2.5
29 CXOU J204717.1-40 825 20 47 17.085 -40 08 25.65 2.3
30 CXOU J204803.5-401028 20 48 03.514 -40 10 28.77 2.0
31 CXOU J204803.3-401047 20 48 03.294 -40 10 47.68 1.8
32 CXOU J204808.1-401842 20 48 08.121 -40 18 42.44 1.8
33 CXOU J204748.3-401504 20 47 48.309 -40 15 04.50 1.8
34 CXOU J204748.3-401600 20 47 48.316 -40 16 00.24 1.8
35 CXOU J204747.8-401512 20 47 47.796 -40 15 12.32 1.7
36 CXOU J204758.1-401735 20 47 58.094 -40 17 35.49 1.5
37 CXOU J204728.4-401429 20 47 28.350 -40 14 29.01 1.4
==================================================================
Source positions have been adjusted for the observation boresight
correction of (0.4" E, 0.1" S), determined by reference to DSS images
of the field, and are uncertain by +/- 0.5" (two-sigma). Approximate
0.3-8.0 keV fluxes are given in units of 1E-06 photons/cm^2/s, and
sources with an identifiable counterpart in the DSS are indicated
("Y"). Source #2, CXOU J204816.1-401108, is unique among these ("Y*")
in that it is associated with a resolved galaxy or galaxies in the
DSS, perhaps reminiscent of the host galaxy of GRB031203 (Prochaska et
al. 2004, astro-ph/0402085).
We expect the X-ray afterglow of XRF040701 to be found in the brighter
portions of the above catalog. In particular, most known X-ray
afterglows would have F_X above the 3E-06 photons/cm^2/s division
indicated in the table.
A second observation of this region is scheduled for July 18, 2004,
with processed data products expected within three days of the
observation. Results of the observation and a comparison of the two
epochs will be reported by GCN at that time."
We acknowledge an extraordinary effort by the CXC in providing rapid
processing of this challenging data-set, thereby enabling this report.
GCN Circular 2621
Subject
XRF 040701, optical observations
Date
2004-07-05T21:55:51Z (21 years ago)
Edited On
2025-09-09T18:36:31Z (a month ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Edited By
courey.elliott@gmail.com
A. de Ugarte Postigo (IAA-CSIC, Granada),
P. Tristram (Univ. of Canterbury),
Sasaki (Stelab, Nagoya Univ.),
J. Gorosabel (IAA-CSIC),
Ph. Yock (Univ. of Auckland), and
A. J. Castro-Tirado (IAA-CSIC),
report:
"We have imaged the entire XRF 040701 error box provided
by HETE-2 (Barraud et al. GCN #2620) with the 0.6-m
telescope (+ MOA camera) at Mt.John Observatory starting
on July 4.459 UT. Observations were performed with the MOA
broad R-band filter with individual exposure times of 300 s.
Visual comparison of the stacked first three images with
the DSS-2 red plate revealed no optical counterpart
candidate brighter than R~20.2."
This message may be cited.
GCN Circular 2620
Subject
XRF040701 (=U11548): a bright XRF detected by HETE
Date
2004-07-03T15:58:32Z (21 years ago)
Edited On
2025-09-09T18:36:29Z (a month ago)
From
Roland Vanderspek at MIT <roland@space.mit.edu>
Edited By
courey.elliott@gmail.com
XRF040701 (=U11548): a bright XRF detected by HETE
C. Barraud, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley,
on behalf of the HETE Science Team;
T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki,
T. Tamagawa, K. Torii, Y. Urata, T. Yamazaki, Y. Yamamoto,
and A. Yoshida, on behalf of the HETE WXM Team;
N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and
HETE Optical-SXC Teams;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE
FREGATE Team
report:
Post-processing analysis of HETE data has revealed the presence of
XRF 040701, a bright XRF. The burst was detected at 13:00:55 UT
and had a duration of roughly 60 seconds. The XRF has been localized
to a circle of radius 8' centered at
RA = 20h 47m 46.3s, dec = -40d 14m 13s (J2000).
Preliminary spectral analysis shows the burst can be best fit with a
power law of index 2.395 +/- 0.3; the 2-25 keV energy fluence is
4.5 +/- 0.8 x 10^-7 erg/cm2.
Details of this burst can be found on the HETE web page at
http://space.mit.edu/HETE/Bursts/GRB040701
This message may be cited.