GRB 090313
GCN Circular 9606
Subject
GRB 090313: optical observations
Date
2009-07-03T10:53:29Z (16 years ago)
From
Graziella Pizzichini at IASF/CNR,Bologna <pizzichini@iasfbo.inaf.it>
E. Maiorano, G. Pizzichini (INAF/IASF Bologna), C. Bartolini, G. Greco,
A. Guarnieri, A. Mantegna, A. Piccioni (Bologna University),
D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"),
F. Terra (Second University of Roma "Tor Vergata"), R. Gualandi
(Bologna Observatory) report:
During the night between 09/03/13 and 09/03/14 we observed the OT of
GRB090313 (Chornock et al., GCN 8979, Mao et al., GCN 8980) with the
1.52 cm telescope of the Bologna Observatory in Loiano. Airmass 1.24
and seeing less than 2" .
Observations were disturbed by the moon. The images were calibrated
using the star quoted by Guidorzi et al., GCN 8989.
By summing 9 images in filter R, with a total duration of 2280s
obtained on March 14 between 00:41:11 and 01:27:59 UT, (mid exposure
time 15.97 hr after the burst) we find R mag = 19.26 +/- 0.15
Our image has been posted in our public directory
from where it can be retrieved by sftp using
sftp publicGRB@137.204.66.221
password: GRB_bo
cd GRB090313
GCN Circular 9017
Subject
Further 15GHz observations of GRB090313
Date
2009-03-23T12:34:06Z (17 years ago)
From
Guy Pooley at MRAO, Cambridge, UK <ggp1@cam.ac.uk>
Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics,
University of Cambridge) reports:
Further observations of the field of GRB090313 have been made with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.
Including those already reported in GCN 9003 and 9007, after minor
recalibration, the flux densities measured were
2009 Mar 16.13 800 +- 80 microJy
2009 Mar 17.06 882 +- 77
2009 Mar 18.05 815 +- 129
2009 Mar 20.16 718 +- 97
2009 Mar 23.05 655 +- 69
Observations lasted between 1 and 3 h, and the resolution is
approximately 60x25 arcsec. The position is consistent with that
of the optical transient (Chornock et al GCN8979).
This message may be quoted.
GCN Circular 9016
Subject
GRB 090313: WSRT Radio Detection
Date
2009-03-23T05:45:35Z (17 years ago)
From
Alexander van der Horst at NASA/MSFC <Alexander.J.VanDerHorst@nasa.gov>
A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of
Amsterdam) report on behalf of a larger collaboration:
"We reobserved the position of the GRB 090313 afterglow at 4.9 GHz with
the Westerbork Synthesis Radio Telescope at March 20 18.89 UT to March 21
6.88 UT, i.e. 7.41 - 7.91 days after the burst (GCN 8980).
We detect a radio source with a flux density of 165 +/- 30 microJy at the
position of the optical counterpart (GCN 8979).
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
GCN Circular 9015
Subject
X-shooter observations of GRB 090313
Date
2009-03-23T02:58:03Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo, S. D�Odorico (ESO PI), J. Vernet, A. Modigliani,
S. Ramsay from ESO Commissioning team;
S. Covino (INAF Brera), H. Flores (Obs. Paris), J. Fynbo, J. Hjorth
(NBI/DARK, U. Copenhagen) and R.A.M.J. Wijers (Astr. Institute,
U. Amsterdam) from the X-shooter GRB team;
F. Hammer (Obs. Paris), L. Kaper (Astr. Institute, U. Amsterdam),
P. Kjaergaard (NBI, U. Copenhagen), S. Randich (INAF Arcetri) as
X-shooter PIs;
P.J. Groot (Radboud Univ. Nijmegen) from the X-shooter Science Team.
On March 15.22 UT we initiated observations of GRB 090313 (Chornock
et al., GCNC 8979; Mao et al., GCNC 8980) with X-shooter at the ESO
Melipal telescope of the Paranal Observatory. X-shooter is the first
of the second-generation VLT instruments and includes three
Echelle spectrographs, the Ultraviolet/Blue (UVB), the Visible (VIS)
and the Near Infrared (NIR), which combined provide a fixed spectral
format and cover in one shot the spectral range 3000 - 24000 A at
medium spectral resolution (R = 4000 - 10000 depending on the arm
and slit width). The mean epoch of the observation was 45.3 hours
after the burst, when the afterglow had faded to R ~ 21.6 (Perley et
al. GCNC 9001; Cobb et al. GCNC 9008). In the 4 x 1500 s combined
spectrum we clearly detect continuum above 5580 A with several
absorption lines; below this, the signal is dominated by background
emission produced by the nearby Moon (90 % illumination at 37 deg
from the field). The spectrum indicates an absorption redshift
of z = 3.3721 � 0.0004 (consistent with that measured by Chornock et
al., GCNC 8994 and Thoene et al., GCNC 9012) through the detection of
Si II (1304.5), C II (1334.5), Si IV (1393.8), Si IV (1402.8), Si II
(1526.7), C IV (1548.2,1550.8), Fe II (1608.5), Fe II (1611.2),
Al III (1854.7), Al III (1862.8), Zn II (2062.6), Fe II (2600.1),
Mg II (2796.3, 2803.5) and Mg I (2853.0). The intervening system
identified by Thoene et al. (GCNC 9012) is resolved into multiple
components through the detection of Fe II, Mg II and Mg I lines with
its main absorption at redshift 1.800. A further system at z = 1.959
shows Fe II, Mg II and Mg I absorption.
The spectra of GRB 090313 will be made public on the ESO web as other
data of scientific relevance obtained during the commissioning of the
instrument.
[GCN OPS NOTE923mar09): Per author's request, the Groot-author's
affiliation was changed.]
GCN Circular 9012
Subject
GRB 090313: VLT spectroscopy
Date
2009-03-19T22:51:47Z (17 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
C. C. Thoene (INAF-OAB), P. D'Avanzo (Univ. Bicocca & INAF-OAB), D.
Fugazza (INAF-OAB), A. de Ugarte Postigo (ESO), V. D'Elia, S. Piranomonte
(INAF-OAR), S. Covino, S. Campana (INAF-OAB), G. Chincarini (Univ.
Bicocca) report, on behalf of the MISTICI collaboration:
We observed the optical afterglow of GRB 090313 (Chornock et al. GCN 8979;
Mao et al. GCN 8980) with the ESO VLT about 1.9 days after the burst with
the FORS2 camera in spectroscopic mode. We took 4 exposures of 20 min each
with the 600I grism covering the range 6800-9300 Angstrom with a
resolution of R=1500.
While we confirm the redshift reported by Chornok et al. (GCN 8994), we
also report the detection of a broad double absorption feature around
observed lambda 7830 and 7840 angstrom that does not fit any transition at
the GRB redshift (z = 3.375). This double feature can be interpreted as Mg
II 2796,2803, each consisting of 2 velocity components with a separation
of about 300 km/s, and could be a signature of an intervening system at
z ~ 1.8. We cannot confirm the presence of Mg I 2852 at z = 1.8 due to the
possible overlap with Mg I 1827 absorption at the redshift of the GRB.
We acknowledge excellent support from the ESO staff, in particular Yuri
Beletsky.
GCN Circular 9011
Subject
GRB090313: radio detection with the VLA
Date
2009-03-19T15:40:15Z (17 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
D. A. Frail (NRAO), and P. Chandra (RMC) report on behalf of a larger
collaboration:
"We observed the field of view of GRB 090313 (GCN 8980) with the Very
Large Array (VLA) in 8.46 GHz frequency on 2009 March 19.23 UT. We
detect a radio source at position (J2000) RA 13:13:36.189, Dec
08:05:49.75, which is within 0.3" of the KAIT optical afterglow position
(GCN 8979). The GRB flux density at 8.46 GHz band is 269+/-31 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 9008
Subject
GRB 090313, SMARTS optical/IR observations
Date
2009-03-18T01:06:29Z (17 years ago)
From
Bethany Cobb at UC Berkeley <bcobb@astro.berkeley.edu>
B. E. Cobb (UC Berkeley) reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained
optical/IR imaging of the error region of GRB 090313 (GCN 8980, Mao
et al.) over four epochs (with UT mid-exposure times of: 2009-03-14 04:27,
2009-03-14 06:55, 2009-03-15 06:30 & 2009-03-17 05:07). Total
summed exposure times for each observation amounted to
36 minutes in R and 30 minutes in J.
The GRB afterglow (e.g. GCN 8979, Chornock et al., GCN 8983, Updike et
al. and GCN 8985, Perley et al.) appears in our imaging to be fading
rapidly after ~19 hours post-burst:
mid-exposure time
(hours post-burst) R mag J mag
19.33 19.70+/-0.04 17.38+/-0.15
21.81 19.90+/-0.04 17.62+/-0.15
45.38 21.57+/-0.12 18.91+/-0.16
92.01 > 22.5 > 19.8
These preliminary magnitudes are calibrated using Landolt standard
stars in the optical and a 2MASS star in the IR.
This rapid fading follows the initial plateau phase that was reported by
Perley et al. (GCN 8985) and de Ugarte Postigo et al. (GCN 8992). This
fading is consistent with the light curve break noted by de Ugarte
Postigo et al. (GCN 8999), though the break appears to occur in this
imaging somewhat earlier than suggested by Yoshida et al. (GCN 9002).
GCN Circular 9007
Subject
Further radio observation of GRB 090313
Date
2009-03-17T09:17:34Z (17 years ago)
From
Guy Pooley at MRAO, Cambridge, UK <ggp1@cam.ac.uk>
Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics,
University of Cambridge) reports further to GCN9003:
We observed the field of GRB 090313 again with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.
The observation was on 2009 Mar 16 23h51m to Mar 17 02h50m
(3d 18h after the burst).
We measured a flux density of 860 microJy with an rms
noise of 75 microJy, at a position consistent with that reported in
GCN9003. The spectrum over that frequency band is consistent with
a spectral index of zero, but is not well constrained because of
the relatively narrow bandwidth and faint flux.
Since the flux density has not changed significantly, while
radio detections of GRBs at this early stage are often highly variable,
the association of this source with the GRB is currently not confirmed.
GCN Circular 9006
Subject
Further Swift/UVOT observations of GRB 090313
Date
2009-03-16T20:55:05Z (17 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P.Schady (MSSL-UCL), F.E.Marshall (NASA/GSFC) and J. Mao (INAF-OAB) report
on behalf of the Swift/UVOT team:
Following on from GCN 8990 (Schady et al.), we report on Swift/UVOT
observations of GRB 090313 for all optical and ultraviolet filters. A
fading source is detected in the v filter and marginally in the b-band
filter at a position consistent with the optical afterglow reported by
Chornock et al. (GCN 8979). These observations are in agreement with the
spectroscopic redshift z=3.375 (Chornock et al., GCN 8994).
The magnitudes and 3-sigma upper limits for GRB 090313 within each
co-added UVOT filter are as follows:
Filter T_mid (hrs) Exp (s) Mag/3-sigma UL
v 11.0 551 20.10 +/- 0.30 (3.6 sigma)
b 11.2 770 21.50 +/- 0.38 (2.8 sigma)
u 8.1 1024 > 21.44
uvw1 8.6 1771 > 21.78
uvm2 9.3 886 > 21.22
uvw2 10.9 886 > 21.58
where T_mid is the weighted mean time of the observations. The values
quoted above are not corrected for the Galactic extinction due to the
reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al.
1998). All photometry is on the UVOT photometry system described in Poole
et al. (2008, MNRAS, 383, 627).
In addition, we note an error in GCN 8990 (Schady et al.), where we
mistakenly labelled the results for the u filter as b and vice versa.
GCN Circular 9005
Subject
GRB 090313: detection with CARMA in 3mm band
Date
2009-03-16T15:21:35Z (17 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
D. C.-J. Bock (CARMA), P. Chandra (RMC), D. A. Frail (NRAO), and S. R.
Kulkarni (Caltech)
report on behalf of a larger collaboration:
"We observed the field of view of GRB 090313 (GCN 8980) with the Combined
Array for Research in Millimeter-Wave Astronomy (CARMA) at a frequency of
92.5 GHz at the mean observation time of 2009 March 14, 0930 UT, within a
day of detection by the Swift. We detect the GRB at the KAIT optical
afterglow
position (GCN 8979) with a flux density of 4.0+/-0.6 mJy. The map rms
noise
is 0.17 mJy.
We acknowledge excellent support from the staff and observers at CARMA."
GCN Circular 9003
Subject
Radio detection of GRB090313
Date
2009-03-16T10:17:38Z (17 years ago)
From
Guy Pooley at MRAO, Cambridge, UK <ggp1@cam.ac.uk>
Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics,
University of Cambridge) reports:
We detected GRB 090313 in an observation with the
AMI Large Array in the frequency range 14.5 to 17.5 GHz.
The observation was on 2009 Mar 16 from 02h00m to 04h24m (2d 18h after the
burst: Mao et al, GCN 8980). We measured a flux density of 820 microJy with
an rms noise of 71 microJy, at a position 13h13m36.0s +08d05'47",
consistent with the optical position (Chornock et al GCN8979).
The resolution is 63"x24" at p.a. 24deg.
This message may be quoted.
GCN Circular 9002
Subject
GRB 090313: MITSuME Okayama observation
Date
2009-03-16T09:58:21Z (17 years ago)
From
Michitoshi Yoshida at Okayama Astrophysical Obs <yoshida@oao.nao.ac.jp>
M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We observed the field of GRB 090313 (Mao et al. GCN 8980) with
the optical three-color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2009-03-14 14:27:51 UT (29.34 hours
after the alert). We detected a point source at the position of
the X-ray - optical - IR afterglow (Chornock and Filippenko GCN
8979; Mao et al. GCN 8991; Updike et al. GCN 8983; Vaalsta et al.
GCN 8996; de Ugarte Postigo et al. GCN 8992, GCN 8999; Perley
GCN 8997; Perley et al. GCN 9001) in Ic band. Photometric result
is listed below. We used GSC2.3 catalog for flux calibration.
Mid-UT Td Exp.Time Ic
-------------------------------------------------------------
2009-03-14 16:30:24 31.3775 hr 60sec x 171 19.3 +/- 0.2
-------------------------------------------------------------
Our result and previous reports (Vaalsta et al. GCN 8996; Perley
GCN 8997; de Ugarte Postigo et al. GCN 8999) show that the
afterglow maintained its brightness from 10 hours to 30 hours
after the burst. de Ugarte Postigo et al. (GCN 8999) and Perley
et al. (GCN 9001) reported steep decline of the I band magnitude
of the object after our observation. Thus the break point of the
light curve may exist at around 31 hours after the burst.
GCN Circular 9001
Subject
GRB 090313: Additional Gemini-S photometry
Date
2009-03-15T20:00:06Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, S. B. Cenko, J. S. Bloom, W. Li, and B. E. Cobb (UC
Berkeley) report:
We conducted additional imaging observations of the optical afterglow of
GRB 090313 (GCN 8979, GCN 8780) consisting of 2x90 seconds in g, r, i,
and z filters on Gemini-S (GMOS) between 08:39 and 08:58 UT on
2009-03-15 (47.7 hours after the burst). At this time we measure an
afterglow magnitude (calibrated using SDSS stars in the field) of r =
21.77 +/- 0.05, confirming the steepening in the decay reported by de
Ugarte Postigo et al. (GCN 8999). The amount of fading relative to our
first epoch (GCN 8997) is consistent across all four filters. We measure
an average decay index (F ~ t^-alpha) of alpha=1.77 over this interval.
GCN Circular 9000
Subject
GRB 090313: WSRT Radio Observations
Date
2009-03-15T16:16:34Z (17 years ago)
From
Alexander van der Horst at NASA/MSFC <Alexander.J.VanDerHorst@nasa.gov>
A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of
Amsterdam) report on behalf of a larger collaboration:
"We observed the position of the GRB 090313 afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at March 14 21.06 UT to March 15
7.27 UT, i.e. 1.50 - 1.92 days after the burst (GCN 8980).
We do not detect a radio source at the position of the optical counterpart
(GCN 8979). The three-sigma rms noise in the map around that position is
114 microJy per beam. The formal flux measurement for a point source at the
position of the optical counterpart is 26 +/- 38 microJy.
We would like to thank the WSRT staff for scheduling and obtaining these
observations."
GCN Circular 8999
Subject
GRB 090313: Light curve steepening
Date
2009-03-15T04:39:47Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota,
A.J. Castro-Tirado (IAA-CSIC), S. McBreen (Univ.
College Dublin) and M.R. Zapatero-Osorio (IAC)
report on behalf of a larger collaboration:
We continued the observations of the afterglow (Chornock
et al. GCNC 8979) of GRB 090313 (Mao et al. GCNC 8980)
from the 1.5m OSN telescope at Sierra Nevada Observatory
(Granada, Spain) in I-band, the 0.8m IAC80 telescope at
Teide Observatory (Tenerife, Spain) in R-band and the
2.5m NOT telescope in nIR bands.
The observations show how the light curve maintains its
brightness until at least 0.8341 days after the burst,
where our last image from OSN shows the afterglow at
I=17.9+/-0.2. This is still stable as compared to the
report of Perley et al. (GCNC 8985) 0.12 days after
the burst and our previous report (de Ugarte Postigo
et al. GCNC 8992) 0.56 days after the burst. We note
that our new magnitude is somehow brighter than the one
reported by Perley et al. at a similar epoch (GCNC
8997). This could be due to a calibration issue. We are
using USNO-B1.0 stars as reference.
From the IAC80 we observe the burst during the plateau
0.6482 days after the burst at a magnitude of 19.1+/-0.1.
At NOT telescope we clearly detect the bright afterglow in
J and Ks bands with NOTCAM 0.7989 days after the burst at a
magnitude of Ks=15.2+/-0.3. We used 2MASS for the calibration,
which is the main source of uncertainty in this value.
Observations continued the following night, where we see a
strong drop in the magnitude of the afterglow, which can be
detected at I=20.2 +/- 0.4, 1.5547 days after the burst,
indicating the presence of a break in the light curve.
GCN Circular 8998
Subject
GRB 090313: TAROT La Silla observatory optical detection
Date
2009-03-15T00:38:51Z (17 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Gendre, B. (LAM-OAMP),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 090313 detected by Swift
(trigger 346386) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.
The observations started 104s after the GRB trigger
The elevation of the field decreased from
37 degrees above horizon and weather conditions
were good but the moon was at 20 deg.
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect the OT reported by Chornock et al. (GCNC 8979)
with a limiting magnitude of:
t0+104s to t0+164s : R > 15.3
The second image is 30.0s exposure in tracking mode:
t0+186s to t0+216s : R > 16.6
We co-added a series of exposures.
The OT is detected:
t0+186s to t0+421s : R = 17.1
All images are unfiltered.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular 8997
Subject
GRB 090313: Gemini-S photometry
Date
2009-03-14T10:38:18Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley (UC Berkeley) reports on behalf of a larger collaboration:
Following our spectroscopic integration on the optical afterglow of GRB
090313 (GCN 8994), we acquired one 60s frame in each of g, r, i, and z
filters using Gemini-S (GMOS) in imaging mode between 05:11 and 05:18 UT
(20.07 hours after the burst). We report the following magnitudes:
g = 21.62 +/- 0.08
r = 20.12 +/- 0.03
i = 19.50 +/- 0.05
z = 19.03 +/- 0.05
The optical SED is well-fit assuming a moderate (A_V ~< 0.4) amount of
SMC-like dust extinction. The presence of a 2175 A dust feature is
strongly ruled out by the z-band measurement.
GCN Circular 8996
Subject
GRB 090313: Zadko Telescope observations
Date
2009-03-14T09:04:51Z (17 years ago)
From
David Coward at U of Western Aus. <coward@physics.uwa.edu.au>
SUBJECT: GRB 090313: Zadko Telescope observations
FROM: D.M Coward at UWA
T. Vaalsta and D.M. Coward report on behalf of the Zadko Telescope Team.
T. Vaalsta, D. Coward, J. Zadko, A. Imerito, D. Blair, R. Burman,
P. Luckas, S. Gordon, K. Frost, A. Fletcher, J. Moore
(University of Western Australia)
M. Todd, M. Zadnik (Curtin University)
M. Boer, A. Klotz (TAROT)
The Zadko telescope started observing the field of
GRB 090313 (trigger=346386, Mao et al. GCN 8980)
4.26h after the Swift trigger, under difficult conditions due to
significant sky brightness from the Moon.
Preliminary photometry of unfiltered images
taken with an iKon DW436BV camera show a slow
decay of the optical afterglow:
Time(s) Magnitude
-------------------------------------
21356 18.02 +/- 0.08
22662 18.49 +/- 0.10
24115 18.49 +/- 0.10
26028 18.62 +/- 0.09
27890 18.78 +/- 0.09
29834 18.84 +/- 0.12
Magnitudes were calibrated with respect to the
nearby USNOB1 star 0980-0264084 (13 13 36.392
+08 04 47.69). The optical afterglow is close
to a 16.37 magnitude galaxy (PGC 1338801).
The Zadko Telescope is currently being commissioned.
This message is quotable in publications
Dr David Coward
Senior Research Fellow
School of Physics
University of Western Australia
Crawley WA 6009
Tel: +61 8 6488 4563
Mobile 0423981240
Fax: +61 8 6488 1170
GCN Circular 8995
Subject
GRB 090313 - PAIRITEL NIR detections
Date
2009-03-14T06:35:06Z (17 years ago)
From
Adam Morgan at PSU/Swift-UVOT <qmorgan@gmail.com>
A. N. Morgan, J. S. Bloom, D. A. Perley (UC Berkeley), and D. Starr
(UCB, LCOGT) report:
We observed the optical afterglow of GRB 090313 (Mao et al. 2009, GCN
8980) with PAIRITEL beginning at 2009-03-13 09:39 UT, 31 minutes after
the Swift Trigger. We detect the afterglow (Chornock et al., GCN
8979) in all 111 47-second mosaics of 7.8 second simultaneous
exposures in the J, H, and Ks taken throughout the night.
Preliminary lightcurves indicate a shallowing of the temporal decay
rate during the 3.5 hours over which the afterglow was observed. The
preliminary photometry yields:
post_burst
t_mid (hr) exp(s) filt mag merr
0.941 1883 J 14.7 0.1
0.941 1883 H 13.8 0.1
0.941 1883 K 12.8 0.1
2.302 2331 J 15.6 0.1
2.302 2331 H 14.6 0.1
2.302 2331 K 13.8 0.1
3.512 1860 J 15.9 0.1
3.512 1860 H 15.4 0.1
3.512 1860 K 14.1 0.1
No correction for Galactic extinction has been made to the above
reported values. Further observations are being taken tonight.
GCN Circular 8994
Subject
GRB 090313: Gemini-S redshift
Date
2009-03-14T05:45:25Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
R. Chornock, D. A. Perley, S. B. Cenko, J. S. Bloom, B. Cobb (UC
Berkeley), and J. X. Prochaska (UCO/Lick) report:
We began a spectroscopic integration on the afterglow of GRB 090313
(Chornock et al., GCN 8979; Mao et al., GCN 8980) using Gemini-South
(GMOS) starting at 04:20 UT on 2009-03-14, approximately 19 hours after
the trigger. We conducted a series of two exposures of 600 seconds each
using the R400 grating, covering a wavelength range of approximately
3900 to 8140 Angstroms. Additional exposures are in progress.
We detect transitions corresponding to C IV, Al II, O I, Si II, Si IV,
and Fe II, as well as a broad absorption feature which we associate with
Lyman-alpha, at a common redshift of z=3.375. We also detect Si II* at
this redshift, identifying this as the redshift of the GRB. While
ruling out an association with the bright nearby SDSS galaxy, this
redshift suggests an extraordinary late-time afterglow luminosity. We
continue to encourage sustained late-time follow-up of this event, which
given its continued brightness (Perley et al., GCN 8985; de Ugarte
Postigo et al., GCN 8992) is likely to continue to be observable to
small-aperture telescopes for an extended period of time.
We thank the Gemini staff for conducting these observations.
GCN Circular 8993
Subject
GRB 090313 optical observations
Date
2009-03-14T01:47:12Z (17 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Markku Nissinen (Varkaus, Finland) reports to the AAVSO High Energy Network
the following optical observations of GRB 090313 (Chornock, Li, and
Filippenko, GCN #8979; Mao et al., GCN #8980):
Markku Nissinen reports the detection of the optical counterpart of GRB
090313 using the GRAS-04 telescope sited in Mayhill, NM, USA. A number
of unfiltered observations with varying exposure times were made using
the 0.25-meter telescope with an SBIG ST8XE CCD camera; observations began
approximately 1 hour post burst. The afterglow was detected in all frames
with astrometric positions matching those given by Chornock, Li, and
Filippenko (GCN #8979) and Updike et al (GCN #8983) to within positional
errors.
The following unfiltered magnitudes were obtained from the observations
using USNO-A2.0 U0975_07146255 (R magnitude = 15.9) as the comparison:
obs midpoint(UT) exptime mag(CR) mag.err
2009-03-13 10:14:41 360 sec 16.5 +/- 0.3 (3 x 120 sec)
2009-03-13 10:27:59 300 sec 16.7 +/- 0.3
2009-03-13 10:39:53 600 sec 16.9 +/- 0.3
A FITS image of the 300-second observation is available at the following URL:
ftp://ftp.aavso.org/grb/MarkkuNissinen_GRB090313_2454904.28608_.fits
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
GCN Circular 8992
Subject
GRB 090313: Ongoing plateau phase
Date
2009-03-13T23:39:20Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota, A.J. Castro-Tirado
(IAA-CSIC) report on behalf of a larger collaboration:
We have observed the field of GRB 090313 (Mao et al. GCNC 8980)
with the 1.5m OSN telescope (Granada, Spain) starting on 22:29 UT
(13.4 hours after the burst). Our I-band images show that the optical
afterglow reported by Chornock et al. (GCNC 8979) is still bright.
Preliminary photometry yields I=17.7+/- 0.3. This would imply that the
plateau phase reported by Perley et al. (GCN 8985) is still ongoing,
half a day later.
Further observations are encouraged
GCN Circular 8991
Subject
GRB 090313: Swift-XRT refined analysis
Date
2009-03-13T23:00:22Z (17 years ago)
From
Jirong Mao at INAF-OAB <jirong.mao@brera.inaf.it>
J. Mao & R. Margutti (INAF-OAB) report on behalf of the Swift-XRT team:
We have analysed 2 ks of XRT data for GRB 090313 (Mao et al. GCN Circ.
8980),
from 26.8 ks to 28.6 ks after the BAT trigger. All the data were taken in
Photon Counting (PC) mode. Using 2038 s of XRT Photon Counting mode data
and 1 UVOT image, we find an astrometrically corrected X-ray position
(using
the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 198.40130, 8.09730 which is equivalent to:
RA (J2000): 13 13 36.30
Dec (J2000): +08 05 50.4
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
The optical candidate (Chornock et al. GCN 8979 and Updike et al. GCN
8983) lies within
the XRT error circle.
The lightcurve can be modeled as a single power-law with an index around
5.4. Given the present
data set the value of this parameter is affected by a large uncertainty.
The PC mode spectrum can be fit with an absorbed simple power-law, with
a photon index
of 2.12 � 0.33 and an absorbing column density of 1.29 � 0.97 e21 cm-2,
in excess of the Galactic
value of 2.10e20 cm-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 5.1e-11 (5.9e-11) erg
cm-2 count-1.
Given the very uncertain power-law decay index, no firm prediction of
the lightcurve can be made.
The results of the automatic XRT analysis are available online at
http://www.swift.ac.uk/xrt_products/00346386.
This circular is an official product of the Swift-XRT team.
GCN Circular 8990
Subject
GRB 090313: Swift/UVOT upper limits
Date
2009-03-13T22:50:45Z (17 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P.Schady (MSSL-UCL) S.T. Holland (CRESST/GSFC/USRA) and J. Mao (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 0903013 once it came out
of Moon constraint, 27ks after the BAT trigger (Mao et al., GCN Circ.
8980). There is no afterglow detection in any of the b, u or uvw1 UVOT
filter observations taken at the optical afterglow position reported by
Chornock et al. (GCN 8979), although by coadding all filters into a single
exposure, a source is marginally detected at the 2-sigma level.
The 3-sigma upper limits for GRB090313 within each UVOT filter are as
follows:
Filter T_mid(hrs) Exp(s) 3-sig Mag UL
u 7.98 223 > 20.81
b 7.82 885 > 21.36
uvw1 7.57 886 > 21.32
where Tmid is the weighted mean time of the observations. The values
quoted above are not corrected for the Galactic extinction due to the
reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al.
1998).
GCN Circular 8989
Subject
GRB 090313: Faulkes Telescope North observations
Date
2009-03-13T18:53:56Z (17 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), A. Melandri, I. A. Steele (Liverpool JMU),
A. Gomboc (U. Ljubljana), D. Bersier, C.J. Mottram, C.G. Mundell,
R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:
The 2-m Faulkes Telescope North (Hawaii) automatically reacted to the
Swift burst GRB 090313 (trigger=346386, Mao et al. GCN 8980).
Observations started about 168 s after the trigger time with filters
BRi. We confirm the detection of the optical counterpart (Chornock et
al. GCN 8979,
Updike et al. GCN 8983, Perley et al. GCN 8985).
The afterglow magnitude was observed to rise and peak around
1.3 ks post burst, followed by a rapid decay out to ~ 10 ks.
Further observations suggest a subsequent flattening.
Filter Tmid(s) Exposure(s) Mag
------------------------------------------------
R 880 60 16.12 +/- 0.07
R 1260 120 15.60 +/- 0.05
R 12290 300 18.20 +/- 0.20
------------------------------------------------
Magnitudes are calibrated with respect to the nearby USNOB1 star
13:13:35.789 +08:05:24.11 assuming its catalogue value of R2=17.08.
Further observations are going to be attempted.
GCN Circular 8988
Subject
GRB 090313: Sustained optical brightness (correction)
Date
2009-03-13T13:55:10Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley (UC Berkeley) reports:
In the preceding circular reporting on the continued optical brightness
at ~3 hours, the reference to Sakamoto et al. (GCN 8982) is in error.
That circular addresses GRB 090309, not GRB 090313. As is clear in
Sakamoto et al. (GCN 8986), this event is clearly a long GRB (T90 = 78
+- 19 sec). I apologize for any confusion.
GCN Circular 8986
Subject
GRB 090313: Swift-BAT refined analysis
Date
2009-03-13T13:48:31Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), J. Mao (INAF-OAB), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090313 (trigger #346386)
(Mao, et al., GCN Circ. 8980). The BAT ground-calculated position is
RA, Dec = 198.400, 8.086 deg, which is
RA(J2000) = 13h 13m 36.0s
Dec(J2000) = +08d 05' 10.7"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 15%.
The mask-weighted light curve shows emission starting before T-100 sec
at which time the burst location came into the BAT FOV during a pre-programmed
target slew. BAT triggered on the peak starting at ~T-20 sec, peaking
at ~T+10 sec, and ending at ~T+90 sec. T90 (15-350 keV) is 78 +- 19 sec
(estimated error including systematics).
The time-averaged spectrum from T-21.3 to T+66.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.91 +- 0.29. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+4.86 sec in the 15-150 keV band
is 0.8 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/346386/BA/
GCN Circular 8985
Subject
GRB 090313: Sustained optical brightness
Date
2009-03-13T13:45:27Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, W. Li, R. Chornock, and A. V. Filippenko (UC Berkeley)
report on behalf of the KAIT GRB team:
We continued observing the position of the optical afterglow (Chornock
et al., GCN 8979) of GRB 080313 (Mao et al., GCN 8980) with the Katzman
Automatic Imaging Telescope (KAIT) in unfiltered and I-band images
lasting until 2.9 hours after the trigger. In spite of significant
contamination due to scattered light from the full moon 20 degrees away,
we continue to (marginally) detect the afterglow in 30-second unfiltered
and 120-second I-band exposures with a magnitude of I = 17.7 +/- 0.4
(calibrated relative to nearby USNO standards) at this time.
Given the usually bright late-time optical afterglow, the equatorial and
nearly anti-sun position, and the possibility of an association with the
bright nearby galaxy (the second object mentioned in Berger et al.,
GCN 8984, which has a spectroscopic redshift of z=0.0235 according to
SDSS), and the unclear high-energy classification of this object
(Sakamoto et al., GCN 8982) we strongly encourage continued follow-up in
spite of the presence of the nearby moon.
[GCN OPS NOTE(13mar09): Per author's request, please see GCN 8988
that explains the mistaken sakamoto reference and the high-energy statement
in the last sentence, as explained in the corerction GCN 8988.]
GCN Circular 8984
Subject
GRB 090313: SDSS object underlying the optical afterglow position
Date
2009-03-13T13:26:03Z (17 years ago)
From
Edo Berger at Harvard <eberger@cfa.harvard.edu>
E. Berger (Harvard) reports:
"Inspection of archival Sloan Digital Sky Survey images reveals a faint
(and apparently extended) object near the position of the optical
afterglow (GCN 8979) of GRB 090313 (GCN 8980). The object is located at:
RA = 13:13:36.08
DEC = 08:05:51.06 (J2000)
which is 2.3" away from the optical afterglow position provided by
Chornock et al. (GCN 8979). The SDSS model magnitudes of this object are:
g = 22.8+/-0.3
r = 21.6+/-0.16
i = 21.1+/-0.18
z = 20.7+/-0.4
A much brigher galaxy is located 17.8" away from the optical afterglow
position at:
RA = 13:13:35.29
DEC = 08:05:38.54 (J2000)
which we consider to be the galaxy mentioned by Chornock et al. (given its
brightness). The SDSS model magnitudes of this galaxy are:
u = 17.07+/-0.01
g = 16.02+/-0.01
r = 15.57+/-0.01
i = 15.32+/-0.01
z = 15.14+/-0.01
A direct determination of the afterglow redshift is required in order to
determine which of the two objects is the host galaxy."
GCN Circular 8983
Subject
GRB 090313, GROND observations
Date
2009-03-13T10:34:51Z (17 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
A. C. Updike (Clemson University), S. Klose (Tautenburg), C. Clemens
and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 090313 (Swift trigger 346386; Mao et al.
2009, GCN 8980) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla
Observatory (Chile).
Observations started at 09:13 UT on March 13, 7 minutes after the GRB
trigger. We confirm that the afterglow candidate reported by Chornock et
al. (GCN 8979) is bright in all bands.
We measure the following preliminary magnitudes at a mean time of about 10
minutes after the burst (Vega mags):
J = 14.0 +/- 0.1
H = 13.1 +/- 0.1
K = 12.3 +/- 0.1
calibrated against 2MASS field stars. Astrometry gives RA, DEC (J2000) =
13:13:36.21, +08:05:49.2 (+/- 0.5 arcsec). As already noted by Chornock
et al., the afterglow is close to a bright galaxy.
These are preliminary data. Data reduction is in progress.
GCN Circular 8981
Subject
GRB 090313: Swift detection of a burst
Date
2009-03-13T09:35:31Z (17 years ago)
From
Jirong Mao at INAF-OAB <jirong.mao@brera.inaf.it>
J. Mao (INAF-OAB), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), G. Tagliaferri (INAF-OAB) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090313 (trigger=346386). The BAT on-board calculated
location is RA, Dec 198.397, +8.107 which is
RA(J2000) = 13h 13m 35s
Dec(J2000) = +08d 06' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a broad series
of multiple peaks from approximately T-10 to T+40. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~4 sec after the trigger. Since
this was an image trigger, the light curve shows only rather weak peaks.
We will have more information upon receipt of the BAT event data
in a few hours.
Due to a Moon observing constraint, Swift cannot slew to the BAT position
until 16:45 UT. There will thus be no prompt XRT or UVOT data for this trigger.
Burst Advocate for this burst is J. Mao (jirong.mao AT brera.inaf.it).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular 8980
Subject
GRB 090313: Swift detection of a burst
Date
2009-03-13T09:34:52Z (17 years ago)
From
Jirong Mao at INAF-OAB <jirong.mao@brera.inaf.it>
J. Mao (INAF-OAB), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA),
R. Margutti (Univ Bicocca&OAB), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), G. Tagliaferri (INAF-OAB) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090313 (trigger=346386). The BAT on-board calculated
location is RA, Dec 198.397, +8.107 which is
RA(J2000) = 13h 13m 35s
Dec(J2000) = +08d 06' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a broad series
of multiple peaks from approximately T-10 to T+40. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~4 sec after the trigger. Since
this was an image trigger, the light curve shows only rather weak peaks.
We will have more information upon receipt of the BAT event data
in a few hours.
Due to a Moon observing constraint, Swift cannot slew to the BAT position
until 16:45 UT. There will thus be no prompt XRT or UVOT data for this trigger.
Burst Advocate for this burst is J. Mao (jirong.mao AT brera.inaf.it).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular 8979
Subject
GRB 090313 OA candidate
Date
2009-03-13T09:27:18Z (17 years ago)
From
Ryan Chornock at UC Berkeley <chornock@astro.berkeley.edu>
R. Chornock, W. Li, and A. V. Filippenko report on behalf of the KAIT GRB team:
The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory slewed to the
position of GRB 090313 and found a new bright source not present in the DSS:
Coordinates (J2000) 13:13:36.21 +08:05:49.8
The bright moon is hindering follow up, but the source appears to be mag ~16 and
is a few arcseconds away from a galaxy.