GRB 090618
GCN Circular 9665
Subject
Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
Date
2009-07-15T08:23:22Z (16 years ago)
From
Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci. <chakraba@bose.res.in>
Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, India), S. K.
Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, India), T. R.
Chidambaram, P. Vinod, S. Sreekumar (VSSC, Thiruvananthapuram, India), Y. D.
Kotov, A. S. Buslov, V. N. Yurov, V. G. Tyshkevich, A. I. Arkhangelskij, R. A.
Zyatkov (MephI, Moscow, Russia) report:
The RT-2 Experiment onboard the CORONAS-PHOTON satellite has clearly detected
GRB 090618 (Schady et al., 2009, GCN 9512) which triggered at T0 = 30507.00
sec (UT) (08h 28m 27s). The satellite was in the SHADOW mode (away from the
SUN) with GOOD time (away from the polar and SAA regions) observation of 700
sec starting at 08h 23m 27sec (UT) and ending at 08h 36m 46.99sec (UT).
The GRB light curve shows a complex profile (Golenetskii et al., 2009, GCN
9553) of time duration of around 150 sec. The burst profile has three main
pulses with the brightest pulse (~700 cts/sec) started at T0+65 sec, the second
one at T0+85 sec and the last one at T0+115 sec.
Both RT-2/S and RT-2/G detectors have registered this multi-structured burst
profile of the light curve in the energy band of 60 - 215 keV. In high-energy
band of 330 - 1000 keV, the profile becomes simple with a single bright peak at
T0+65 sec. It is also noted that the burst width decreases with the increase in
the energy band, a quiet natural phenomena of GRB burst profile. The burst was
incident at an angle of 77 degrees to the detector axis. It showed the typical
Band spectrum with peak energy at about 180 keV and integrated 20 keV - 1MeV
flux of 2.8 X 10^-4 ergs/ cm^2.
The light curve is available at the web-site:
http://csp.res.in/rt2_files/grb090618-lc.html
GCN Circular 9613
Subject
GRB 090618: Mondy optical observations
Date
2009-07-04T00:32:08Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Klunko (ISTP), A. Volnova (SAI MSU), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:
We observed the afterglow (Schady et al., GCN 9512; Cenko et al., GCN 9513;
Perley, GCN 9514; Rujopakarn et al., GCN 9515) of the Swift GRB 090618
between (UT) Jun. 18 18:14 -- 18:43 with 1.5m telescope of Sayan
observatory (Mondy). The afterglow is detected in stacked images.
Preliminary photometry of the stacked images based on USNO-B1.0 star
1683-0077955 (RA=19 36 36.34 Dec=+78 21 07.00) assuming R=16.57 is
following:
T0+ Filter, Exposure, mag., err.
(d) (s)
0.4083 R 10x30 18.60 +/-0.10
GCN Circular 9597
Subject
GRB 090618: RTT150 optical observations
Date
2009-06-30T14:12:04Z (16 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
I. Khamitov, M. Parmaksizoglu, T. Ak, Z. Eker (TUG),
Z. Aslan (Kultur Uni.), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, N. Sakhibullin (KSU/AST),
report:
We observed the OT (Schady et al., GCN 9512; Cenko et al., GCN 9513;
Perley, GCN 9514; Rujopakarn et al., GCN 9515) of the Swift GRB 090618
with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK
National Observatory, Turkey), in Rc band during three nights 25,26 and 27
June 2009 and in B band in 26 June.
Every night we made 3x900s exposures in Rc band and in 26 June we made
additionally 3x900 in B band. The OT is detected in all stacked images in
Rc. The brightness of OT is not changed inside of photometric error.
Our preliminary estimate of its magnitude during these observations is
m_Rc=22.3+/-0.1 (7.68, 8.64, 9.58 days after the burst).
We found no OT on stacked B-image. The limiting magnitude of the frame is
mlim_B=23.4 (8.68 days after the burst).
--
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GCN Circular 9592
Subject
GRB090618: 15GHz radio emission faded
Date
2009-06-29T11:26:44Z (16 years ago)
From
Guy Pooley at MRAO, Cambridge, UK <ggp1@cam.ac.uk>
Further to GCN 9532, Guy Pooley (Cavendish Astrophysics, U. Cambridge)
reports on behalf of the AMI consortium that the radio emission
at 15 GHz from GRB090618 has faded.
Data from the AMI Large Array are given below, including data
taken on 090619 reported in GCN 9532:
yymmdd.ddd hhmm-hhmm S rms
UT microJy microJy
090619.073 0245-0415 425 120
090619.208 0415-0545 640 120
090620.182 0340-0505 415 87
090621.275 0536-0736 139 91
090622.175 0328-0457 63 96
090627.021 0013-0048 -127 190
These results may be quoted in publications.
GCN Circular 9576
Subject
GRB090618: HCT optical observations
Date
2009-06-25T21:41:30Z (16 years ago)
From
D.K. Sahu at Indian Inst of Astrophysics,Bangalore <dks@iiap.res.in>
G.C. Anupama, U.K. Gurugubelli, D.K. Sahu report
Optical afterglow of GRB090618 (Schady et al., GCN 9512) was observed
with the 2m. Himalayan Chandra Telescope of the Indian Astronomical
Observatory, Hanle, India. The optical afterglow was observed in
Bessell R filter and it was detected in all the frames.
The preliminary magnitude of the optical afterglow, calibrated
using the USNO B1 (R1 magnitude) of the nearby stars in the
GRB field is as under:
Date Mid UT Exposure R Mag Error
18-06-2009 19:29 300sec 18.70 0.07
18-06-2009 19:36 300sec 18.75 0.06
19-06-2009 22:08 2x300+450 20.30 0.09
GCN Circular 9575
Subject
GRB 090618: SARA Second Epoch Observations
Date
2009-06-25T21:08:25Z (16 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria Updike, Sean Brittain, Dieter Hartmann (Clemson University), Andrew
Colson, Renata Cumbee, Brianne Hackett, Josiah Lewis, and Marten Kronberg
(SARA REU) report:
We re-observed the field of GRB 090618 (Schady et al., GCN 9512) using the
0.9m SARA telescope at Kitt Peak National Observatory beginning 20 hours
after the trigger and continuing for 3 hours. Our observations consisted
of 45 sec exposures in the R and I bands under good conditions. The
afterglow is detected in stacked images. Magnitudes are given below as
compared to the USNOB.1 catalog. Time is given in days after the trigger;
exposure time in seconds.
Time Filter Exp Mag
------------------------------------
0.84 R 1215 19.4 +/- 0.1
0.86 I 1215 18.8 +/- 0.1
http://www.saraobservatory.org/
GCN Circular 9570
Subject
GRB 090618: Correction to GCN 9568
Date
2009-06-24T15:47:37Z (16 years ago)
From
Kazutaka Yamaoka at Aoyama Gakuin U <yamaoka@phys.aoyama.ac.jp>
K. Kono (Univ. of Miyazaki),
on behalf of the Suzaku WAM team, report:
There are some garbled characters and a wrong value reported
in Kono et al. (GCN 9568).
The correct values are as follows:
1-s peak flux : 9.83 (-0.36, +0.26) x 10^-6 erg/cm^2/s
The fluence in 100 - 1000 keV: (1.58 +/- 0.07) x 10^-4 erg/cm^2
The photon index
for time-averaged spectrum : 2.32 +/- 0.04
alpha for 1-s peak spsctrum: 1.21 +/- 0.13
We apologize for any inconvenience.
GCN Circular 9568
Subject
GRB 090618: Suzaku WAM observation of the prompt emission
Date
2009-06-24T13:05:44Z (16 years ago)
From
Kenta Kono at Miyazaki U <kenta0514@astro.miyazaki-u.ac.jp>
K. Kono, A. Daikyuji, E. Sonoda, N. Ohmori, H. Hayashi, K. Noda,
Y. Nishioka, M. Yamauchi (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The bright, long GRB 090618 was detected by the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 08:28:25.592 UT (=T0).
The observed light curve shows a multi-peaked structure
starting at T0-5 s and ending at T0+149 s,
with a duration (T90) of about 105 seconds.
The fluence in 100 - 1000 keV was (1.58 $B!^(B 0.07) x10-4 erg/cm2.
The 1-s peak flux measured from T0+65 s was 20.7 (-0.9, +0.8) photons/cm2/s
and 9.83(-0.36, +0.26) x10-5 erg/cm2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-5 s
to T0+149 s is well fitted by a single power-law with a photon index
of 2.32 $B!^(B 0.04 (chi2/d.o.f = 51/51).
The 1-s peak spectrum is well fitted by a power-law with exponential
cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha: 1.21 $B!^(B 0.13, and
Epeak: 623 (-39, +44) keV (chi2/d.o.f. = 41/50).
Due to the brightness of this burst, a 3% systematic error
was added for low energy channels.
All the quoted errors are at 90% confidence level,
The light curves for this burst are now available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html
GCN Circular 9563
Subject
PAIRITEL observations of GRB 090618
Date
2009-06-23T01:00:35Z (16 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan, C. R. Klein, J. S. Bloom, (UC Berkeley), report:
We observed the location of the optical afterglow of GRB 090618
(Schady et al., GCN 9512) with the 1.3m PAIRITEL located at Mt.
Hopkins, Arizona. Observations began at 2009-06-18 08:29:40 UT, 71
seconds after the Swift Trigger, under non-ideal sky conditions. In
the initial images, we detect a variable infrared source (identified
as the IR afterglow) in individual frames of 7.8 second simultaneous
exposures in the J, H, and Ks bands.
The preliminary photometry on selected stacks of images yield the
following photometry:
time
post burst exp. filt mag m_err
[s] [s]
210 93.6 J 12.7 0.1
210 93.6 H 12.1 0.1
210 93.6 Ks 11.4 0.2
2818 327 J 15.1 0.1
2818 327 H 14.6 0.1
2818 327 Ks 13.7 0.1
10636 585 J 16.2 0.2
10636 585 H 15.7 0.2
10636 585 Ks >14.8 3-sigma
Intermittent clouds led to highly variable transmission and sky
brightnesses during the PAIRITEL observations. All magnitudes are
given in the Vega system, calibrated to 2MASS. No correction for
Galactic extinction has been made to the above reported values.
Further analysis is ongoing.
GCN Circular 9553
Subject
Konus-Wind and Konus-RF observations of GRB 090618
Date
2009-06-22T14:41:45Z (16 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
P. Oleynik, M. Ulanov, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:
The long GRB 090618 (Schady et al. 2009, GCN 9512)
triggered Konus-Wind
at T0=30504.974 s UT (08:28:24.974),
and Konus-RF instrument onboard CORONAS-PHOTON s/c
at T0=30507.060 s UT (08:28:27.060).
The burst light curve shows a smooth multi-peaked structure
with a duration of ~160 s. Significant spectral evolution
was observed during the burst.
--
As observed by Konus-Wind the burst had
a fluence of (2.5 � 0.06)x10-4 erg/cm2,
and a 64-ms peak flux measured from T0+63.616 s
of (1.6 � 0.2)x10-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+142 s) can be fitted
(in the 20 keV - 2 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -1.28 � 0.02,
the high energy photon index beta = -2.66(-0.2, +0.14),
the peak energy Ep = 186 � 8 keV (chi2 = 103/60 dof).
The spectrum at the maximum count rate,
measured from T0+62.720 to T0+64.0 s, is well fitted
(in the 20 keV - 2 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -0.99 (-0.06, +0.07),
the high energy photon index beta = -2.29(-0.5, +0.23),
the peak energy Ep = 440 � 70 keV (chi2 = 52/55 dof).
--
As observed by Konus-RF the burst
had a fluence of (2.82 � 0.06)x10-4 erg/cm2
(both in the 20 keV - 2 MeV energy range),
and a 500-ms peak flux measured from T0+63.0 s
of (1.6 � 0.1)x10-5 erg/cm2/s
(in the 20 keV - 1.5 MeV energy range).
The time-integrated spectrum of the burst
(from T0-1.4 to T0+113.0 s) can be fitted
(in the 20 keV - 2 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -1.28 � 0.03,
the high energy photon index beta = -3.06(-0.5, +0.3),
the peak energy Ep = 220 � 8 keV (chi2 = 240/132 dof).
The spectrum at the maximum count rate,
measured from T0+63.0 to T0+63.5 s, is well fitted
(in the 20 keV - 1.5 MeV range) by GRB (Band) model
for which:
the low-energy photon index alpha = -0.89 (-0.1, +0.3),
the high energy photon index beta = -2.56(-1.0, +0.6),
the peak energy Ep = 385 (-136, +64) keV (chi2 = 78/74 dof).
--
All the quoted values are preliminary.
The quoted errors are at the 90% confidence level.
The light curves of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090618_T30504/
GCN Circular 9548
Subject
GRB 090618: RTT150 optical observations
Date
2009-06-22T09:50:24Z (16 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
A. Galeev, I. Bikmaev, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
We observed the OT (Schady et al., GCN 9512; Cenko et al., GCN 9513; Perley,
GCN 9514; Rujopakarn et al., GCN 9515) of the Swift GRB 090618 with
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey), in BRc bands, starting at 22 Jun, 00:03 UT,
i.e. approximately 3.65 days after the burst, using TFOSC.
We made 3x900s exposures in Rc band and 2x900 in B band. The OT is detected
in all images. Using the same USNO-B1 star as it was used by Rumyantsev and
Pozanenko (GCN 9539) we estimate Rc magnitude as m_Rc=21.60+/-0.04 (3.68
days after the burst).
The finding chart can be found at:
http://hea.iki.rssi.ru/grb/090618/indexeng.html
GCN Circular 9542
Subject
GRB090618: Spectrum and photometry from 6.0m BTA
Date
2009-06-21T09:05:13Z (16 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
T. Fatkhullin, A. Moskvitin (SAO-RAS Niznijh Arkhyz, Russia),
A.J. Castro-Tirado (IAA-CSIC Granada), A. de Ugarte Postigo
(ESO, INAF/OAB), on behalf of a larger collaboration, report:
We have observed the field of GRB090618 (Schady et al.,
GCN 9512) with the 6-m telescope of the SAO RAS in
Caucasus. We obtained B, Rc and Ic images as well as a
low-resolution spectrum under non favorable weather conditions.
The range and resolution of the spectrum were 3900-9200AA
and FWHM=15-17A, respectively. A preliminary processing of
the spectrum showed a faint emission line at 5748.55A which we
interpret as [OII] 3727A. A corresponding redshift of 0.54 is in
full agreement with one obtained by Cenko et al. (GCN 9518).
Because of strong night sky OH bands and low resolution of the
spectrum we could not clearly detect expected Hbeta and
[OIII]4959,5007A lines. The photometry was calibrated using a
number of SDSS stars in the field. Below we present a summary
of some of our observations:
middle date, UT results
-------------------------------------------------------
spectrum 19.977 June 2009 [OII]3727A detection
Rc 19.941 June 2009 20.51 +/- 0.06
This message can be cited.
GCN Circular 9541
Subject
GRB 090618: BOAO V-band Observation
Date
2009-06-21T06:09:55Z (16 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
M. Im (CEOU/Seoul National Univ), Y.-B. Jeon (KASI), and
Y. Urata (NCU)
We observed GRB090618 (Schady et al. GCN 9512) in V using
a 15.5cm refractor at Bohyunsan Optical Astronomical Observatory
in Korea, operarted by the Korea Astronomy Space Science Institute.
A series of exposures were taken starting at 2009 June 18, 11:54:19.
The afterglow, identified earlier by many groups
(GCN 9513, 9514, 9515, 9520, 9522), was clearly detected
at V=17.9 +- 0.1 magnitude at mid-time of 2009 12:55:07
(about 4hr 26.6min after the BAT trigger).
The photometry was calibrated against nearby SDSS stars
where the transformation of SDSS magnitude to V-band magnitude
was carried out using the recipe of Chonis & Gaskell (2008).
GCN Circular 9539
Subject
GRB 090618: ZTSh optical observations
Date
2009-06-21T01:01:06Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We observed the afterglow (Schady et al., GCN 9512; Cenko et al., GCN 9513;
Perley, GCN 9514; Rujopakarn et al., GCN 9515) of the Swift GRB 090618
between (UT) Jun. 18 19:51 - Jun. 19 00:51 with Shajn telescope of CrAO.
We detect afterglow in every BVRI of 60 s exposure images of the series.
Coordinates of the afterglow are RA(J2000): 19 35 58.77 Dec(J2000): +78 21
24.2 with uncertainties of 0.3 arcsec.
Preliminary photometry of selected images based on USNO-B1.0 star
1683-0077955 (RA=19 36 36.34 Dec=+78 21 07.00) assuming R=16.57 is
following:
T0+ Filter, Exposure, mag., err.
(d) (s)
0.4763 R 60 18.60 +/-0.05
0.5680 R 60 18.87 +/-0.03
0.6496 R 60 19.17 +/-0.04
0.6796 R 60 19.19 +/-0.10
The power low index of light curve approximation between 0.48 - 0.65 days
is ~ -1.6, while after 0.65 days after burst onset we observe flattening of
the light curve. A finding chart can be found at
http://grb.rssi.ru/GRB090618/GRB090618_090618_R_ZTSh.gif
GCN Circular 9538
Subject
GRB 090618 : WSRT radio detection
Date
2009-06-20T19:59:19Z (16 years ago)
From
Atish Kamble at U. of Amsterdam <A.P.Kamble@uva.nl>
Atish Kamble (University of Amsterdam), A.J. van der Horst (NASA/ORAU)
and Ralph Wijiers (University of Amsterdam) reports on behalf of
a larger collaboration :
"We observed the position of GRB 090618 afterglow at 4.9 GHz
using the Westerbork Synthesis Radio Telescope between
June 19.78 to 20.30 UT i.e. 1.7 days after the burst (GCN 9512,
GCN 9532, GCN 9533). The radio afterglow was clearly detected
and its measured flux density is about 501 +/- 47 microJy.
We would like to thank the WSRT staff for scheduling and carrying out
these observations."
GCN Circular 9537
Subject
GRB090618, underlying supernova search
Date
2009-06-20T09:08:39Z (16 years ago)
From
Arnon Dar at Technion-Israel Inst. of Tech <arnon@physics.technion.ac.il>
S. Dado and A. Dar report:
The inferred photon spectral index Gamma=2.01+/-0.05 of the early time
X-ray afterglow of the relatively nearby bright GRB090618 (z=1.54, GCN
9518) from the Swift XRT observations (Evans et al.
http://www.swift.ac.uk/xrt_spectra/00355083/) implies, in the CB model
(e.g. ApJ 696 (2009), 994), an asymptotic achromatic power-law decline of
the afterglow with a spectral index beta=1.01+/-0.05 and a temporal index
alpha=beta+1/2=1.51+/-0.05. The R-band light curve of the anticipated
underlying supernova akin to SN1998bw is expected to reach maximum
brightness magnitude R=23.9 (Galactic extinction included) around July 10,
2009 (approximately 22 days after GRB090618). Using the latest optical
measurements reported in GCN 9531 and GCN 9536, the GRB afterglow is
expected to decay by July 10, 2009 to a magnitude R=24.6+/-0.20 yielding
R=23.4+/-0.3 for the optical transient superposed on a bright host galaxy
with r=22.7 +/- 0.3 (GCN 9526). Like in the case of GRB 030319 (ApJ 594
(2003), L89), the search for an underlying supernova (GCN 9526) in
GRB060618 may be more successful using large telescopes with high
resolution for photometric and/or spectroscopic follow up measurements of
its optical afterglow.
GCN Circular 9536
Subject
GRB090618: OAA-OAUV Optical observations
Date
2009-06-19T23:05:06Z (16 years ago)
From
Alberto Fernandez-Soto at IFCA (CSIC/UC,Santander) <fsoto@ifca.unican.es>
A. Fernandez-Soto (IFCA-Santander), V. Peris (OAUV-Valencia), and
J. Alonso-Lorite (OAUV-Valencia) report:
We have observed the field of GRB090618 (Schady et al., GCN 9512) with
the OAUV-0.4m telescope at the Observatorio Astronomico de Aras (OAA)
in Aras de Alpuente (Valencia, Spain). Observations began after local
sunset on June 18 (UT 19:32, (t-t0)~11.1 hours).
We took 23 four-minute exposures using a Johnson R filter. The
individual frames have been combined in five groups. The afterglow
reported in GCN9512 and confirmed by Cenko et al. (GCN 9513) is
clearly detected in all five images, with magnitudes and times:
UT(middle) Exposure R Error
---------- -------- ----- -----
21:30:03 5x4min 18.67 0.14
21:50:51 5x4min 18.57 0.09
22:42:14 4x4min 18.62 0.09
23:21:44 5x4min 18.92 0.13
23:45:19 2x4min 18.96 0.13
All magnitudes have been calibrated using stars in the field and the
USNO-B1 catalog (R1 mags).
Our results agree with those reported by Cano et al. (GCN 9531), and
support the presence of a break in the R-band decay, which happened at
(t-t0) ~ 14.6 hours.
A lightcurve combining our data and previous GCNs is posted at
http://ayalga.uv.es/~fsoto/grb090618
OAA is operated by the Observatori Astronomic de la Universitat de
Valencia (OAUV).
GCN Circular 9535
Subject
GRB 090618: Fermi GBM observation
Date
2009-06-19T22:55:39Z (16 years ago)
From
Sheila McBreen at MPE <smcbreen@mpe.mpg.de>
Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:
"At 08:28:26.66 UT on 18 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090618 (trigger 267006508 / 090618353)
which was also detected by Swift/BAT (Schady et al. 2009, GCN 9512)
and AGILE (Longo et al. 2009, GCN 9524).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 133 degrees.
The GBM light curve consists of 4 pulses
with a duration of about 155 s (8-1000 keV).
The time-averaged spectrum from T0 to T0+140 s is
adequately fit by a Band function with Epeak = 155.5 (+11.1/-10.5) keV,
alpha = -1.26 (+0.06/-0.02), and beta = -2.50 (+0.15/-0.33).
We observe significant spectral evolution within the fitted
time interval.
The event fluence (8-1000 keV) in this time interval is
(2.70 +/- 0.06)E-4 erg/cm^2. Using standard cosmology
(Omega_matter = 0.27, Omega_lambda = 0.73, H0=71)
and the reported redshift of 0.54 (Cenko et al. 2009, GCN 9518)
the isotropic equivalent energy in the 8-1000 keV band is
E_iso = 2.0E+53 erg.
The 1-sec peak photon flux measured starting from T0+63 s
in the 8-1000 keV band is 73.4 +/- 2.0 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 9534
Subject
GRB 090618, Swift-BAT refined spectral analysis
Date
2009-06-19T18:13:00Z (16 years ago)
From
Tilan Ukwatta at GSFC/GWU <tilan.ukwatta@gmail.com>
T. Sakamoto (GSFC/UMBC), T. N. Ukwatta (GWU/GSFC),
S. D. Barthelmy (GSFC), (i.e. the Swift-BAT team):
Using the data set from T-373 to T+962 sec from the
recent telemetry downlink, we report further spectral
analysis of BAT GRB 090618 (trigger #355083)
(Schady, et al., GCN Circ. 9512).
The time-averaged spectrum from T-4.4 to T+213.6 sec
is best fit by a power law with an exponential cutoff.
This fit gives a photon index 1.42 +/- 0.08,
and Epeak of 134 +/- 19 keV (chi squared 14.6
for 56 d.o.f.). For this model the total fluence in
the 15-150 keV band is 1.05 +/- 0.01 x 10^-04 erg/cm2
and the 1-sec peak flux measured from T+65.38 sec in
the 15-150 keV band is 38.8 +/- 0.8 ph/cm2/sec.
A fit to a simple power law gives a photon index
of 1.72 +/- 0.02 (chi squared 55.8 for 57 d.o.f.).
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/355083/BA/
GCN Circular 9533
Subject
VLA radio detection of GRB 090618
Date
2009-06-19T14:04:59Z (16 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of a larger collaboration:
"We used the Very Large Array to observe the field of view toward the
GRB 090618 (GCN 9512) at a frequency of 8.46 GHz on 2009 June 19.33 UT.
We observed the radio afterglow of the GRB at P60 optical afterglow
position reported by Cenko et al. (GCN 9513). The GRB radio afterglow
flux density is 383+/-47 uJy. Further observations are planned.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 9532
Subject
GRB 090618 15GHz radio detection
Date
2009-06-19T09:50:32Z (16 years ago)
From
Guy Pooley at MRAO, Cambridge, UK <ggp1@cam.ac.uk>
Guy Pooley (Cavendish Astrophysics, U. Cambridge) reports on behalf
of the AMI collaboration:
The AMI Large Array (the rebuilt Ryle Telescope) was used to observe
the field of GRB 090618 (Schady et al, GCN9512) on 2009 June 19
from 02h45m to 05h45m UT (18.25 to 21.25h after the burst)
using the position from Cenko et al (GCN9213).
The observing band was 14.6 to 17.5 GHz and the rms noise 85 microJy.
The angular resolution is approx. 50" x 20".
We make a clear detection of a source at the position of the GRB
with a flux density 550 microJy. A split of the data suggests that
the flux density increased from 425 to 640 microJy between the
first and second halves of the observation, but this is barely
statistically significant.
There is no radio source visible at that position in the NVSS (1.4GHz).
This report may be quoted in publications.
GCN Circular 9531
Subject
GRB090618 - Continued optical monitoring and light curve break
Date
2009-06-19T08:56:19Z (16 years ago)
From
Zach Cano at ARI/John Moores Liverpool <zec@astro.livjm.ac.uk>
Z. Cano (Liverpool JMU), C. Guidorzi (U. Ferrara), D. Bersier,
A. Melandri, I.A. Steele, R.J. Smith, C. Mundell (Liverpool JMU)
report, on behalf of a large collaboration:
Following our report of observations (GCN 9520) we continued monitoring
the field of GRB090618 (Swift trigger 355083) on the Liverpool Telescope
(La Palma) from 13.6 hours to 17.9 hours post burst in R and i bands.
Below is a summary of a few R-band images:
t_exp t-T0 R-mag
300s 13.6 hours 18.9 � 0.1
300s 15.6 hours 19.1 � 0.1
300s 17.9 hours 19.3 � 0.1
The calibration is still preliminary and determined against stars in
the USNO catalog.
We note a break in the R-band light curve, and find a decay index of
alpha~1.4 by 17.9 hours post burst, as compared to alpha~0.7 previously
reported (GCNs 9517, 9520).
GCN Circular 9530
Subject
GRB 090618: Swift-BAT refined analysis
Date
2009-06-19T00:43:00Z (16 years ago)
From
Tilan Ukwatta at GSFC/GWU <tilan.ukwatta@gmail.com>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings
(GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm
(GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), P. Schady (MSSL-UCL),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-5 to T+320 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090618 (trigger #355083)
(Schady, et al., GCN Circ. 9512). The BAT ground-calculated position is
RA, Dec = 294.008, 78.352 deg, which is
RA(J2000) = 19h 36m 01.8s
Dec(J2000) = +78d 21' 07.1"
with an uncertainty of 0.46 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 62.5%.
The mask-weighted light curve shows two episodes with four prominent
peaks. The first episode is a smooth 50 sec peak starting at T-5 sec,
and ends at T+45 sec. The second episode is about 275 second long
and consists of three overlapping peaks. The second episode starts
at ~T+45 sec, the first peak is around T+62 sec, the second peak is
around T+80, and the third is around T+112 and finally ends at
T+320 sec. Our T90 (15-350 keV) is 113.2 +/- 0.6 sec (estimated
error including systematics).
The time-averaged spectrum from T-5 to T+109 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.712 +/- 0.018. The fluence in the 15-150 keV band is
1.06 +/- 0.01 x 10^-4 erg/cm2. The 1-sec peak photon flux measured
from T+65.12 sec in the 15-150 keV band is 38.9 +/- 0.8 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/355083/BA/
GCN Circular 9529
Subject
GRB 090618: SARA observations
Date
2009-06-18T23:00:02Z (16 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria Updike, Sean Brittain, Dieter Hartmann (Clemson University), Andrew
Colson, Renata Cumbee, Brianne Hackett, Josiah Lewis, and Marten Kronberg
(SARA REU) report:
We observed the field of GRB 090618 (Schady et al., GCN 9512) using the
0.9m SARA telescope at Kitt Peak National Observatory beginning 1.5 hours
after the trigger and continuing for 2 hours. Our observations consisted
of 45 sec exposures in the I and R bands. The afterglow was detected in
every image. Magnitudes are given below as compared to the USNOB.1
catalog. Time is given in seconds after the trigger; exposure time in
seconds.
Time Filter Exp Mag
------------------------------------
5400 I 45 16.2 +/- 0.05
6300 R 45 16.8 +/- 0.05
Further observations are planned.
http://www.saraobservatory.org/
GCN Circular 9528
Subject
GRB090618: Swift-XRT team refined analysis
Date
2009-06-18T19:06:26Z (16 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A.P. Beardmore (U. Leicester) and P. Schady (MSSL-UCL) report on
behalf of the Swift-XRT team:
We have analysed 12.3 ks of Swift-XRT data for GRB 090618 (Schady et
al. GCN Circ. 9512), from 124 s to 25.7 ks after the BAT trigger. The
data span five orbits and comprise 2.3 ks in Windowed Timing (WT) mode
and 10.0 ks in Photon Counting (PC) mode. The UVOT-enhanced XRT
position for this burst was reported by Evans et al. (GCN 9521).
The burst was initially very bright in X-rays, observed at a rate
of ~8000 count s^-1, and decayed rapidly with a slope of ~6, before
breaking at T+310 s to a shallower decay slope of 0.71 +/- 0.02.
A further break is seen at T+4700 s with the decay steepening to
1.22 +/- 0.05.
The WT spectrum from T+250 s to T+1065 s can be fit by an absorbed
powerlaw with a photon index of 2.11 +/- 0.03 and intrinsic absorption
of (1.78 +/- 0.14) x 10^21 cm^-2 (at z=0.54, Cenko et al., GCN 9518),
in addition to the Galactic column of 5.8 x 10^20 cm^-2 in the
direction of the source (Kalberla et al. 2005). The observed 0.3-10
keV flux for this model is (8.2 +0.2 -0.1) x 10^-10 erg cm^-2
s^-1. The corresponding unabsorbed flux is (1.16 +/- 0.02) x 10^-9
erg cm^-2 s^-1.
If the light curve continues to decay at the same rate we predict a
count rate of 0.13 count s^-1 at T+24 hours, which corresponds to an
observed (unabsorbed) 0.3-10 keV flux of 4.9 x 10^-12 (7.2 x 10^-12)
erg cm^-2 s^-1.
The results of the XRT team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00355083.
This circular is an official product of the Swift-XRT team.
GCN Circular 9527
Subject
GRB090618: Swift/UVOT bright afterglow detection
Date
2009-06-18T19:00:10Z (16 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL) reports on behalf of��the Swift UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090618 129s
after the BAT trigger (Schady et al., GCN Circ. 9512) and a
decaying��source is detected in all UVOT filters at the position reported
in Schady et al. (GCN Circ. 9512), consistent with refined XRT error
circle��(Evans et al., GCN Circ. 9521) as well as the optical afterglow
position reported in a number of other GCNs (GCN Circ. 9512, 9514, 9515).
The detection of the afterglow of GRB 090618 in all filters puts��an upper
limit on the redshift��of z < 1.7, consistent with the redshift constraints
reported by Cenko et al. (GCN Circ. 9518).
The magnitudes for the first UVOT observation of GRB 090618 in each filter
are as follows:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 129 279 147 14.27+/-0.01
v 671 691 19 15.60+/-0.09
b 596 616 19 15.92+/-0.06
u 340 590 246 14.62+/-0.01
uvw1 720 740 19 15.09+/-0.08
uvm2 695 715 19 15.23+/-0.12
uvw2 647 667 19 15.27+/-0.10
The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel��et al. 1998). The photometry is on the UVOT photometric system
described��in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 9526
Subject
GRB 090618: SDSS host detection
Date
2009-06-18T16:52:52Z (16 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@astro.ku.dk>
Daniele Malesani (DARK/NBI) reports:
I inspected the SDSS images of the field of GRB 090618 (Schady et al.,
GCN 9512). A faint object is visible in the r and i frames at the
position of the optical afterglow (e.g. Schady et al., GCN 9512; Cenko,
GCN 9513), likely the host galaxy of the GRB. Nothing convincing is
visible in the u, g, and z images. Compared to nearby SDSS stars, the
magnitudes are r = 22.7 +- 0.3 and i = 22.2 +- 0.4. The bright host
magnitude is consistent with the low redshift reported by Cenko et al.
(GCN 9518)
A supernova as bright as SN 1998bw (Galama et al. 1998, Nature, 395,
670) would peak at r(AB) ~ 23.6 at z=0.54.
GCN Circular 9524
Subject
GRB 090618: AGILE observations
Date
2009-06-18T15:21:44Z (16 years ago)
From
Marco Feroci at IASF/INAF <feroci@iasf-roma.inaf.it>
F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
M.Trifoglio, A. Bulgarelli, F. Gianotti F. Fuschino, M. Marisaldi,
C.Labanti, M.Galli, G.DiCocco (INAF/IASF Bologna), S. Cutini, C.
Pittori (ASDC), M.Tavani, E.Striani, G. Pucella, F. D'Ammando,
V.Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini
(INAF/IASF Rome), E. Del Monte, M. Feroci, Y. Evangelista, I. Donnarumma,
L. Pacciani, P. Soffitta, E. Costa, F.Lazzarotto, I. Lapshov, M. Rapisarda
(INAF/IASF Rome) A. Giuliani, A. Chen, S. Mereghetti, F. Perotti, P.
Caraveo (INAF/IASF Milano), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S.
Vercellone (INAF/IASF Palermo), P. Picozza, A. Morselli (INFN Roma-2), M.
Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), A.
Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi, P. Santolamazza, F.
Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:
The AGILE satellite detected GRB 090618 (P. Schady et al. GCN #9512)
at about 36 degrees off axis.
Super-AGILE, operating in the 18-60 keV energy range, triggered and
localized the burst in the 1-D region of the field of view at a position
consistent with the Swift/BAT localization. The emission from this bright
GRB with a complex lightcurve was detected at high significance despite
the large off-axis direction.
AGILE-MCAL, operating in the 350 keV - 100 MeV energy range, triggered
this GRB at 08:28:24.772 UT (T0). The MCAL overall burst duration is
about 100 sec. The burst is composed by three main pulses, the
brightest starting at T0+62sec and lasting about 14 seconds.
The total MCAL spectrum between T0 and T0+120 sec can be fit by a
simple powerlaw with photon index 3.16 (-0.30, +0.39) (90% c.l.),
with reduced chi^2 0.99 (9 d.o.f.), in the 0.5-10 MeV energy range.
The estimated fluence is (3.2 +/- 0.6) 10^{-5} erg cm^-2 in the same
energy range.
From a preliminary analysis of the AGILE-GRID data in the energy range
30 MeV-30 GeV no significant gamma-ray emission above 30 MeV is detected
in the GRB error box during both the first and second main pulse for
a total duration of about 130 sec. A preliminary upper limit is 0.1
ph cm^-2 over a 130 s duration.
GRB 090618 provides a clear evidence for a class of GRBs bright below
a few MeV, showing the lack of significant gamma-ray emission above 30
MeV.
GCN Circular 9522
Subject
GRB 090618: LOAO R-band Observation
Date
2009-06-18T15:01:20Z (16 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
M. Im, W.K. Park (CEOU/Seoul National Univ) and Y. Urata (NCU)
on behalf of EAFON team.
We observed GRB090618 (Schady et al. GCN 9512) in R using
the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by
the Korea Astronomy Space Science Institute.
The observation started about 50min after the BAT trigger.
The first image taken with the mid-point at June 18,
09:52 UT (53m42s after the BAT trigger) shows a clear detection
of the afterglow at R=15.9 +- 0.1 mag, reported earlier by a number of
groups (GCN 9513, 9514, 9515, 9520).
The photometry was calibrated against R1mag of USNO-B1 stars
in the vicinity of GRB.
More data were taken, and they are being analyzed.
We thank the LOAO operator, Y. Baek for her assistance of this
observation.
GCN Circular 9521
Subject
GRB 090618: Enhanced Swift-XRT position
Date
2009-06-18T15:00:51Z (16 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2422 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090618, 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 = 293.99304, +78.35702 which is equivalent
to:
RA (J2000): 19h 35m 58.33s
Dec (J2000): +78d 21' 25.3"
with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 9520
Subject
GRB 090618 Faulkes Telescope North observations
Date
2009-06-18T13:32:21Z (16 years ago)
From
David Bersier at Liverpool John Moores U <dfb@astro.livjm.ac.uk>
A.Melandri (Liverpool JMU), C. Guidorzi (U. Ferrara), D. Bersier,
Z. Cano, I.A. Steele, C.G. Mundell (Liverpool JMU), P. O'Brien,
N. Tanvir (U. Leicester) on behalf of a larger collaboration report:
We have been monitoring the field of GRB090618 (Swift trigger 355083),
with the Faulkes Telescope North (Hawaii), starting ~80 minutes after
the trigger time (Schady et al. GCN 9512).
Observations were performed with BVRi filters. The optical afterglow
reported by Cenko (GCN 9513), Perley (GCN 9514) and Rujopakarn et al.
(GCN 9515) is clearly visible and detected in all filters.
We find a magnitude of R=17.01 � 0.03 (at 2.5 hrs after the burst)
and R=17.25 � 0.05 (at 3.1 hrs). We confirm the decay of alpha~0.7
reported by Li et al. (GCN 9517).
Observations are continuing.
GCN Circular 9519
Subject
Optical observations of GRB 090618
Date
2009-06-18T12:37:13Z (16 years ago)
From
Alberto Carraminana at AzTEC <alberto@inaoep.mx>
A. Carraminana (INAOE), C. Alvarez Ochoa (UNACh)
and G. Miramon (OAGH-INAOE) report:
We clearly detected the optical counterpart of GRB 090618 (GCN 9512)
with the 2.1m telescope of the Observatorio Astrofisico
Guillermo Haro at Cananea, Sonora, Mexico. Observations started
at 08:43 UT, 14 minutes after the BAT trigger and continued
until dawn. Observations were made under non photometric conditions.
We measured a lineal faddening of the burst compared to
a reference star of amplitude 0.5 magnitudes between t=870s
to 1600s. A non calibrated graph is available at
http://www.inaoep.mx/~alberto/gamma/grb090618_lc.jpg
Spectroscopic data were also obtained and are under analysis.
GCN Circular 9518
Subject
GRB 090618: Lick/KAST Spectroscopy
Date
2009-06-18T12:37:12Z (16 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, D. A. Perley (UC Berkeley), V. Junkkarinen, M. Burbidge (UC
San Diego), and K. Miller (UCO Lick Observatory) report on behalf of a
larger collaboration:
We have obtained a spectrum of the afterglow (GCNs 9512, 9513, 9514, 9515)
of GRB 090618 with the KAST spectrograph on the 3-m Shane telescope at
Lick Observatory. Observations began at 08:48 UT on 18 June 2009,
approximately 20 minutes after the burst. On the blue channel (using the
830/3460 grism, providing wavelength coverage from 3200 - 4400 A), we
detect a number of strong absorption features that we identify as Mg II,
Mg I, and Fe II at a common redshift of z = 0.54. We believe this likely
to be the redshift of the GRB, as the lack of Lyman-alpha absorption
limits the GRB host to lie at z <~ 1.6.
Further analysis is in progress.
GCN Circular 9517
Subject
GRB 090618: OA behavior from KAIT
Date
2009-06-18T11:21:26Z (16 years ago)
From
Weidong Li at UC Berkeley KAIT/LOSS <weidong@astron.berkeley.edu>
W. Li, D. A. Perley, and A. V. Filippenko, University of California at
Berkeley, on behalf of the KAIT GRB team:
We have analyzed the KAIT observations on GRB 090618 (GCN 9512) as
reported in GCN 9514. Our first 2s unfiltered observation started
at 08:29:44 UT, 75 s after the BAT trigger. The OA as reported in
GCN 9512, 9513, 9514, and 9515 is clearly detected. Subsequent
observations show that the OA declined and reached a bottom at t=92 s,
then brightened and reached a peak at t=120 s. After the peak, the
OA declined as a smooth power-law, with an obvous change of decay
index at t ~ 600 s (from alpha = -1.08 +/- 0.05 to -0.70 +/- 0.02).
Selected photometry, all unfiltered calibrated to the R band via USNO B1:
t_mid(seconds) exp(s) mag mag_err
---------------------------------------
76 2.0 13.61 0.03
92 2.0 13.99 0.04
117 2.0 13.50 0.03
237 20.0 14.02 0.02
436 20.0 14.73 0.02
729 20.0 15.26 0.02
2601 20.0 16.22 0.02
7329 120.0 17.02 0.03
GCN Circular 9516
Subject
GRB 090618: planned XMM-Newton observation
Date
2009-06-18T11:11:39Z (16 years ago)
From
Sergio Campana at INAF-OAB <sergio.campana@brera.inaf.it>
S. Campana (INAF-Osservatorio astronomico di Brera)
and the XMM-Newton SOC (ESAC)
XMM-Newton will observe GRB 090618 at location
(RA=19h 35m 58.69s, DEC=-+78d 21' 24.4", J2000),
starting at 13:30 UT, on June 18, 2009,
for an exposure of 24 kiloseconds.
Coordinated observations are welcome.
GCN Circular 9515
Subject
GRB 090618: ROTSE-III Detection of Optical Counterpart
Date
2009-06-18T08:57:11Z (16 years ago)
From
Wiphu Rujopakarn at U AZ/Steward <wiphu@as.arizona.edu>
W. Rujopakarn (Steward), T. Guver (U Arizona), S. B. Pandey (Michigan),
and F. Yuan (Michigan) report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090618 (Swift trigger 355083, Schady et al., GCN 9512). The first image
was at 08:28:53.7 UT, 23.9 s after the burst (6.7 s after the GCN notice
time). The unfiltered images are calibrated relative to USNO A2.0. We
detect a 14.1 magnitude source with coordinates:
19:35:58.65 +78:21:24.03 (J2000), with positional uncertainty of 1" or
better
start UT mag mlim(of image)
----------------------------------
08:28:29.8 14.1 16.2
This source is not visible in DSS (second epoch), 2MASS or the MPChecker
database. Continuing observations are in progress.
GCN Circular 9514
Subject
GRB 090618: KAIT optical afterglow
Date
2009-06-18T08:52:20Z (16 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley reports on behalf of the KAIT GRB team:
The Katzman Automatic Imaging Telescope (KAIT) responded to GRB 090618
and began taking data at 08:31:10 (UT). A bright (~14th magnitude)
optical afterglow is visible in the initial set of exposures at the
following position:
RA 19:35:58.80
dec +78:21:25.5
Further follow-up is in progress.
GCN Circular 9513
Subject
GRB090618: P60 Optical Afterglow
Date
2009-06-18T08:49:37Z (16 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:
We have imaged the field of GRB090618 (Swift trigger 355083) with the
automated Palomar 60-inch telescope beginning at 08:30 UT on 18 June 2009
(approximately 2 minutes after the burst). At the edge of the XRT error
circle we detect a bright point source with coordinates:
RA: 19:35:58.68 Dec: +78:21:24.4 (J2000.0)
Using several SDSS stars in the field as reference, we estimate
an initial magnitude of r' ~ 13.8. Given the brightness of the source,
we consider it highly likely to be the optical afterglow of GRB090618.
Further observations are ongoing.
GCN Circular 9512
Subject
GRB 090618: Swift detection of a bright burst with optical afterglow
Date
2009-06-18T08:48:39Z (16 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@astro.psu.edu>
P. Schady (MSSL-UCL), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
P.A. Curran (MSSL-UCL), C. Guidorzi (U Ferrara), J. A. Kennea (PSU),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), M. H. Siegel (PSU), G. Stratta (ASDC) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 08:28:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090618 (trigger=355083). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 294.021, +78.353 which is
RA(J2000) = 19h 36m 05s
Dec(J2000) = +78d 21' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed multi peak
structure with a duration of about 130 sec. The peak count rate
was ~40,000 counts/sec (15-350 keV), at 80 sec after the trigger.
The XRT began observing the field at 08:30:30.8 UT, 120.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 293.9897, +78.3576 which is equivalent to:
RA(J2000) = 19h 35m 57.52s
Dec(J2000) = +78d 21' 27.3"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 28 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 128 seconds after the BAT trigger. There is a
candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 19:35:58.69 = 293.99456
DEC(J2000) = +78:21:24.3 = 78.35676 with a 90%-confidence
error radius of about 0.74 arc sec. This position is 4.6 arc sec.
from the center of the XRT error circle. The estimated magnitude is
14.36 with a 1-sigma error of about 0.01. No correction has been
made for the expected extinction corresponding to E(B-V) of 0.09.
Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk).
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.)