GRB 070209
GCN Circular 6218
Subject
Short-Hard GRB 070209: PROMPT Observations
Date
2007-03-19T22:10:03Z (20 years ago)
From
Seth Johnson at U.North Carolina <spjohnso@physics.unc.edu>
S. Johnson, D. Reichart, J. Haislip, M. Nysewander, A. LaCluyze, K.
Ivarsen, J. A. Crain, A. Foster and A. Trotter report on behalf of the
University of North Carolina:
Skynet observed the localization of short-hard GRB 070209 (Sato et al., GCN
6086) with one of the 16" PROMPT telescopes at CTIO beginning 67 seconds
after the burst in BVIR.
Our images include nearly all of the BAT error circle, as well as all three
X-ray sources of Stratta et al. (GCN 6095). No new source is detected
within this region to the following 3-sigma limiting magnitudes:
Filter Mean Time Integration Limiting Calibration
Since GRB Time (sec) Magnitude Stars*
B 0:01:12 10 16.07 1-3
V 0:01:39 10 16.83 1-4,7
R 0:02:11 20 17.33 9-12
I 0:02:49 20 17.24 9-12
B 0:03:27 10 16.27 1-4
V 0:04:11 40 18.08 1-6
R 0:05:16 40 17.94 9-14
I 0:06:13 40 17.68 9-12,15
B 0:07:35 80 18.17 1-6
V 0:09:14 80 18.57 1-6
R 0:10:57 80 18.62 9-15
I 0:12:36 80 18.26 9-14
B 0:14:44 120 18.82 1-6
V 0:17:28 120 19.12 1-6
R 0:20:14 120 18.81 9-14
I 0:23:00 120 18.66 9-15
B 0:25:43 120 18.41 1-6
V 0:29:33 240 19.36 1-6
R 0:34:34 240 19.19 9-14,16
I 0:40:19 240 18.64 9-14,16
B 0:45:45 240 18.41 1-6
V 0:51:06 240 19.37 1-2,4-6
R 0:58:55 560 19.77 9-10,12-14,16
I 1:10:51 560 19.32 9-10,12-14,16
B 1:21:29 480 19.09 1-2,4-7
V 1:33:25 560 19.72 1-2,4-8
*We calibrated the field in B and V using stars from the NOMAD catalog and
in R and I using stars from the USNO-B1.0 catalog. The NOMAD calibration
stars are (1) 0426-0037919, (2) 0426-0037965, (3) 0425-0038295, (4)
0425-0038481, (5) 0425-0038222, (6) 0426-0037846, (7) 0427-0037455 and (8)
0426-0038099. The USNO-B1.0 calibrations stars are (9) 0426-0037895, (10)
0426-0037941, (11) 0425-0038287, (12) 0425-0038472, (13) 0425-0038213, (14)
0426-0037820, (15) 8058-00193-1 and (16) 0426-0038075.
GCN Circular 6119
Subject
GRB 070209: Swift XRT refined analysis
Date
2007-02-20T15:35:37Z (20 years ago)
From
Matteo Perri at ISAC/ASDC <perri@asdc.asi.it>
G. Stratta, M. Perri, M. L. Conciatore (ASDC), D. N. Burrows (PSU) and
G. Sato (GSFC/ISAS) report on behalf of the Swift/XRT team:
The field of the short hard BAT GRB 070209 (Sato et al., GCN Circ. 6086)
has been re-observed by Swift in two epochs at about T+5 days and T+9
days after the BAT trigger. The XRT exposures in Photon Counting mode
were 19.4 ks and 22.8 ks, respectively. We found no X-ray sources within
the BAT refined error circle (Sakamoto et al., GCN Circ. 6087). The three
X-ray sources reported by Stratta et al. (GCN Circ. 6095) close to the
BAT error circle are still detected at the same count rate level of the
first follow-up observation. We conclude that none of these sources is
the afterglow of the burst.
The three sigma upper limit on the 0.7-10 keV count rate during the first
observation within the BAT error circle was about 7e-4 cts/s. Assuming an
absorbed power-law spectral model with Galactic NH (2.3e20 cm-2) and a
photon index of 2 this corresponds to an observed 0.7-10 keV flux of
about 3e-14 erg cm-2 s-1.
This circular is an official product of the Swift XRT Team.
GCN Circular 6101
Subject
GRB 070209: Redshift of a galaxy in the error circle of XRT source
Date
2007-02-13T07:20:20Z (20 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie Observatories) and D. Fox (Penn State) report on
behalf of a larger collaboration:
"Using GMOS on the Gemini-south telescope we obtained a 2400 spectrum of
an apparent galaxy located within the error circle of XRT source #1 (GCN
6095). This is the only X-ray source which exhibits signs of fading and
is the nearest to the BAT error circle of this burst (GCN 6087). We find
that the redshift of the galaxy is z=0.314 based on the detection of CaII
H&K, as well as [OII] and [OIII] emission lines. At this redshift, the
isotropic-equivalent energy of the burst is 2.6e48 erg."
GCN Circular 6095
Subject
GRB 070209: Swift XRT analysis
Date
2007-02-10T19:49:44Z (20 years ago)
From
Matteo Perri at ISAC/ASDC <perri@asdc.asi.it>
G. Stratta, M. Perri, M. L. Conciatore (ASDC), D. N. Burrows (PSU) and
G. Sato (GSFC/ISAS) report on behalf of the Swift/XRT team:
We have analysed the first 12 orbits of Swift XRT data on the BAT GRB
070209 (Sato et al., GCN Circ. 6086). Data in Photon Counting mode
started at 03:35:10 UT, 89 s after the BAT trigger. With an exposure time
of 26.9 ks we did not find X-ray sources within the BAT refined error
circle (Sakamoto et al., GCN Circ. 6087). We note that the following
X-ray sources are detected in the 0.7-10 keV band in the proximity of the
BAT error circle:
Source #1: CR = (1.1+/-0.3)e-3 cts/s RA/Dec(J2000)=03 04 57.3 -47 19 35.6
Source #2: CR = (7.5+/-2.2)e-4 cts/s RA/Dec(J2000)=03 05 04.9 -47 18 42.8
Source #3: CR = (1.4+/-0.3)e-3 cts/s RA/Dec(J2000)=03 04 39.1 -47 27 57.3
The estimated uncertainty of the positions of the three sources is about
5 arcsec (90% containment).
Source #1 lies 3.1 arcmin from the refined BAT position, just outside the
error circle. We note that this source may be fading, but due to the small
number of counts we are unable to determine clearly if the source is
decaying. A Swift follow-up observation will be performed in a few days to
confirm whether source #1 is fading or not.
This circular is an official product of the Swift XRT Team.
GCN Circular 6087
Subject
GRB 070209, Swift-BAT refined analysis of the short hard burst
Date
2007-02-09T06:31:50Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-240 to T+302 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 070209 (trigger #259803)
(Sato, et al., GCN Circ. 6086). The BAT ground-calculated position is
RA, Dec = 46.213, -47.376 deg which is
RA(J2000) = 03h 4m 51.2s
Dec(J2000) = -47d 22' 34.2"
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
The mask-weighted lightcurve has a single peak. T90 (15-350 keV) is
0.1 +- 0.02 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+0.1 is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.55 +- 0.39. The fluence in the 15-150 keV band is 1.1 +- 0.3 x 10^-8
erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the
15-150 keV band is 2.4 +- 0.6 ph/cm2/sec. All the quoted errors are
at the 90% confidence level.
GCN Circular 6086
Subject
GRB 070209: Swift detection of a short hard burst
Date
2007-02-09T03:53:23Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
G. Sato (GSFC/ISAS), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
M. M. Chester (PSU), C. Gronwall (PSU),
S. T. Holland (CRESST/GSFC/USRA), S. Immler (GSFC/USRA),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. Perri (ASDC),
M. Stamatikos (NASA/ORAU), G. Stratta (ASDC) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 03:33:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070209 (trigger=259803). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 46.237, -47.370 which is
RA(J2000) = 03h 04m 57s
Dec(J2000) = -47d 22' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single spike
with a duration of about 0.2 sec. The peak count rate
was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began taking data at 03:34:59 UT, 78 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in the
image and no prompt position is available. We are waiting for down-linked
data to detect and determine a position for the source.
UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 83 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical
3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the
list of sources generated on-board covers 100% of the BAT 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 0.01.