GRB 070612A
GCN Circular 6714
Subject
GRB070612A: Radio upper limit from GMRT
Date
2007-08-07T05:39:00Z (18 years ago)
From
Dipankar Bhattacharya at IUCAA <dipankar@iucaa.ernet.in>
Sabyasachi Pal, C.H. Ishwara-Chandra, Dipankar Bhattacharya and
Atish P. Kamble report on behalf of a larger collaboration:
We observed the field of GRB 070612A (Grupe et al, GCN 6509) at
1280 MHz, using the Giant Meterwave Radio Telescope, from
MJD 54305.08 to 54305.26 (UT 2007 Jul24 01:55:21 to 06:12:36).
This interval corresponds to 41.97-42.15 days after the burst.
The afterglow was not detected. The formal flux density at the
position of the optical afterglow (Cenko et al, GCN 6525)
was 109 +/- 64 micro Jy (1-sigma).
We thank the GMRT staff who made this observation possible.
GMRT is run by the National Centre for Radio Astrophysics of
the Tata Institute of Fundamental Research.
This message may be cited.
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GCN Circular 6600
Subject
VLA detection of GRB 070612A in C Band
Date
2007-07-05T21:49:36Z (18 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB
070612A (GCN 6509) at a frequency of 4.88 GHz on 2007 June 30th at
20.66 UT. We detect the GRB afterglow at P60 optical afterglow position
(GCN 6517). The flux density of the GRB is 189+/-56 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 6583
Subject
GRB 070612A: Allen Telescope Array Observations
Date
2007-06-27T23:06:44Z (19 years ago)
From
Josh Bloom at UC Berkeley <jbloom@astron.berkeley.edu>
R. Forster, M. Wright, J. Hare, J. S. Bloom, G. C. Bower (UC
Berkeley) report on behalf of a large collaboration:
"Using the Allen Telescope Array (ATA, http://ral.berkeley.edu/ata/),
we observed GRB 070612A (Grupe et al., GCN 6509) at 1.4 GHz on 2007
June 16 UT and at 5 GHz on 2007 June 17 UT. The observations made use
of 8 antennas outfitted with dual-polarization receivers. At the
location of the optical afterglow (Updike et al., GCN 6515), we
obtained 3-sigma limits of 50 mJy at 1.4 GHz and 10 mJy at 5 GHz for
the flux density of GRB 070612A at these epochs. The data were
calibrated versus the QSS 0927+392. At L-band the 8 brightest NVSS
were measured to be located within 10% of the synthesized beamwidth
and 100 mJy of the NVSS flux densities. The limits reported herein
are consistent with the tentative WSRT detection at 4.9 GHz (Horst et
al. GCNs 6549, 6576).
A 42-antenna ATA is currently being commissioned."
This message may be cited.
GCN Circular 6576
Subject
GRB 070612A: Second Epoch WSRT Radio Observations
Date
2007-06-24T10:19:49Z (19 years ago)
From
Alexander van der Horst at U of Amsterdam <avdhorst@science.uva.nl>
A.J. van der Horst, R.A.M.J. Wijers, K. Wiersema (University of Amsterdam),
and E. Rol (University of Leicester) report on behalf of a larger
collaboration:
"We reobserved the position of the GRB 070612A afterglow (GCN 6509) at
4.9 GHz with the Westerbork Synthesis Radio Telescope at June 20 7.91 UT
to 19.76 UT, i.e. 8.22 - 8.71 days after the burst.
At the position of the optical counterpart (GCN 6515, GCN 6525) and the
tentative radio counterpart (GCN 6549), we measure a formal flux of
72 +/- 27 microJy, i.e. a possible radio source at 2.7 sigma significance.
In a combined image of the two epochs of WSRT observations, at June 15 and
June 20, the average formal flux is 53 +/- 19 microJy, a 2.8 sigma
detection. Therefore, we cannot state with certainty whether the radio
afterglow (or the possible host galaxy) of GRB 070612A is detected.
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
GCN Circular 6566
Subject
Observations of GRB070612A at Calar Alto
Date
2007-06-22T08:24:34Z (19 years ago)
From
Elena Pian at ITESRE-CNR,Bologna <pian@iasfbo.inaf.it>
S. Taubenberger (MPA), P. Mazzali (MPA & INAF - OATs), W. Hillebrandt
(MPA), J. Alves (CAHA), U. Thiele (CAHA), S. Pedraz (CAHA),
A. Guijarro (CAHA), M. Alises (CAHA) and E. Pian (INAF - OATs) report:
We observed the afterglow (Updike et al., GCN 6515; Cenko et al., GCN
6525) of GRB 070612A (Grupe et al., GCN 6509) with the Calar Alto 2.2m
Telescope equipped with CAFOS on 2007 Jun 13.86, 14.86 and 15.87 UT.
In all three nights images were taken in the BVRI bands, at high
airmass (~ 3), and under variable seeing and transparency conditions
(2.0" - 5.6" fwhm, clear - thin clouds).
The afterglow was detected on Jun 13.86 at V = 20.40+-0.23 and
R = 19.79+-0.10 (calibrated against the Landolt field PG1633 under
photometric conditions; only measurement errors reported). In R up
to 25% of contamination from the underlying galaxy can be expected
(D'Avanzo et al., GCN 6558).
From the rest of the images only limits could be derived, in
particular V > 20.0 / 19.8 and R > 18.9 / 19.6 on Jun 14.86 / 15.87,
respectively.
Our Jun 13.86 R-band magnitude is consistent with the afterglow's
steep power-law decay suggested by observations with other telescopes
(cf. Malesani et al., GCN 6555, and references therein).
GCN Circular 6558
Subject
GRB 070612A: TNG optical observations
Date
2007-06-20T10:55:14Z (19 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
P. D'Avanzo, S. Covino (INAF-OAB), M. Della Valle (INAF-OA Arcetri), E.
Pian (INAF - OATs), G. Tagliaferri on behalf of the CIBO collaboration,
P. Mazzali (INAF - OATs & MPA), A. Magazzu` and Noemi Pinilla-Alonso
(INAF - TNG) report:
We observed the afterglow (Updike et al., GCN 6515; Cenko et al., GCN
6525) of GRB 070612A (Grupe et al., GCN 6509) with the Italian 3.6m TNG
telescope equipped with
the DOLORES camera on 2007 Jun 18.89 and 19.90 UT. Because of visibility
constraints, images have been taken at high airmass (~ 3). The average
seeing was of about 1.7". An extended object is clearly visible at the
position of the optical afterglow (Cenko et al., GCN 6525) and its
brightness remains constant at both epochs at a level of R ~ 21.4
(calibrated against the USNO B1.0 catalog). This is consistent to what
reported by Malesani et al. (GCN 6555) and suggests that the afterglow's
brightness is now below the host galaxy level.
We acknowledge the support of the TNG staff.
GCN Circular 6556
Subject
GRB070612A: Gemini Spectroscopic Redshift
Date
2007-06-19T04:37:40Z (19 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko (Caltech), D. B. Fox, A. Cucchiara (Penn State), B. P. Schmidt
(Australia National University), E. Berger (Carnegie), P. A. Price (IfA),
and K. C. Roth (Gemini) report on behalf of a larger collaboration:
Starting on 2007 June 17 at 06:10 UT we used GMOS on the Gemini North
telescope to obtain a 600 s spectrum of the afterglow + host galaxy of GRB
070612A (Grupe et al., GCN 6509). The spectrum was taken in twilight at
very high airmass (~ 3.2) and covers the wavelength range ~ 4000-8120 A.
We find a strong, broad (~ 10 A) emission line at ~ 6229 A that, based on
the lack any blueward emission features, we identify as [O II] 3727 at
z=0.617. We also notice another possible emission feature at the very red
edge of our spectrum corresponding to H-beta at the same redshift. No
other features are detected either in emission nor in absorption.
We note that this redshift is significantly larger than the original SDSS
photometric redshift (z ~ 0.1) noted by Cenko, Ofek, and Fox (GCN
6525