GRB 080430
GCN Circular 8368
Subject
GRB 080430: optical observations
Date
2008-10-13T15:39:36Z (17 years ago)
From
Graziella Pizzichini at IASF/CNR,Bologna <pizzichini@iasfbo.inaf.it>
F. Terra (Second University of Roma "Tor Vergata"), F. Munz (INAF/IASF
Bologna) G. Greco, C. Bartolini, A. Guarnieri,A. Piccioni (Bologna
University), D. Nanni (INAF/OAR and Second University of Rome "Tor
Vergata"), G. Pizzichini(INAF/IASF Bologna), S. Galetti and S. Bernabei
(Bologna Observatory) report:
During the night between 08/04/30 and 080501 we observed the OT of
GRB080430 (Guidorzi et al., GCN 7647, Klotz, Boer & Atteia, GCN 7646)
in Rc, V, B AND I with the 1.52 cm telescope of the Bologna Observatory
in Loiano in good weather conditons, airmass between 1 and 1.6,
seeing less than 4".
Calibration was obtained from the NOMAD catalog in the Rc filter and from
the SDSS observations by Cool et al. in GCN 7649 for the other filters.
We obtain the following magnitudes
obs midpoint duration filter mag error
seconds
2454587.40325 600 Rc 19,47 0,11
2454587.41120 600 V 19,20 0.12
2454587.42067 600 Rc 19,75 0,11
2454587.43274 1200 B 19,54 0,12
2454587.44788 600 Rc 19,60 0,15
2454587.45720 600 I 19,03 0,05
2454587.46673 600 Rc 19,75 0,11
2454587.47927 600 V 19,44 0,12
2454587.48806 600 Rc 19,96 0,10
2454587.51098 600 Rc 20,28 0,09
2454587.52303 600 Rc 20,01 0,09
2454587.53175 600 Rc 20,27 0,15
2454587.53946 600 I 19,14 0,06
2454587.54819 600 Rc 20,53 0,10
Our images have been posted in our public directory
from where they can be retrieved by sftp using
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo
directory: /home/publicGRB/GRB080430/
GCN Circular 7809
Subject
GRB 080430: optical observations
Date
2008-06-04T15:58:14Z (17 years ago)
From
Graziella Pizzichini at IASF/CNR,Bologna <pizzichini@iasfbo.inaf.it>
F. Terra (Second University of Roma "Tor Vergata"), F. Munz (INAF/IASF
Bologna) G. Greco, C. Bartolini, A. Guarnieri,A. Piccioni (Bologna
University), D. Nanni (INAF/OAR and Second University of Rome "Tor
Vergata"), G. Pizzichini(INAF/IASF Bologna), S. Galleti and S. Bernabei
(Bologna Observatory) report:
During the night between 08/04/30 and 08/05/01 we observed the OT of
GRB080430 (Guidorzi et al., GCN 7647, Klotz, Boer & Atteia, GCN 7646)
with the 1.52 cm telescope of the Bologna Observatory in Loiano in good
weather conditons, airmass between 1 and 1.6, seeing less than 4".
We obtained a total of 14 frames in Rc, V, B and I.
Rc magnitudes went from 19.47 +- 0.11 at 2454587.40325 UT to 20.53 +- 0.10
at 2454587.54819 UT.
Rc calibration was obtained from the NOMAD catalog.
Our images have been posted in our public directory
from where they can be retrieved by sftp using
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo
directory: /home/publicGRB/GRB080430/
GCN Circular 7739
Subject
GRB080430: optical observations
Date
2008-05-16T20:15:26Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), Ju.
Babina (CrAO), V. Petkov, A. Kurenya (BNO INR RAS), A. Pozanenko (IKI) on
behalf of larger GRB follow up collaboration report:
We observed the afterglow (Klotz et al. GCN 7646, Guidorzi et al. GCN 7647,
Jelinek et al. GCN 7648) of GRB080430 (Guidorzi et al. GCN 7647) with
Zeiss-600 of Mt.Terskol observatory on May. 01. The afterglow is detected
in a combined image. A photometry of the OT against USNO-B1.0 stars is
following:
UT, Exposure, R_mag
(mid time)
May.01.8795 15x90s 20.9 +/-0.3
The message may be cited.
GCN Circular 7717
Subject
GRB 080430
Date
2008-05-14T21:48:32Z (17 years ago)
From
Joel Nicolas at none <joel.nicolas@wanadoo.fr>
J.Nicolas reports:
Visible Obervation afterglow radiation of the start gamma GRB080430
TEL 0.28-m F/6.5 reflector
Observatory:Vallauris 07:30:49 E 43:34:40 N B51
Composite of 26 images of 90s without filter
Photometry at magnitude 19
Date 08/04/30 22h15 UT
Using the USNO-A2 catalog, the source is located at:
RA (J200O) = 11h 01m 14.76s
DEC (J2000) = +51d 41' 08.46"
The Image can be found at
http://astrosurf.com/jnicolas/sursaut_gamma.htm
GCN Circular 7681
Subject
GRB 080430: TLS imaging one day after the GRB
Date
2008-05-05T20:00:39Z (17 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, F. Ludwig, R. Filgas and S. Klose (TLS tautenburg) report:
We imaged the afterglow (Klotz et al., GCN 7646) of GRB 080430 (Guidorzi
et al., GCN 7647) with the TLS Schmidt telescope one day after the GRB.
Direct RRM observations a day earlier were unobtainable due to persistent
bad weather. We obtained 22 180 second images starting with twilight under
good conditions and at airmass 1. The afterglow is visible on all single
images.
From the SDSS photometry of the field (Cool et al., GCN 7649), we find
that the bright star southeast of the afterglow, at R.A. = 11:01:16.88,
Dec. = +51:40:38.6 has g = 17.111, r = 16.539 and i = 16.377. Using the
transformations of Jester et al. 2005, we find Rc = 16.458 for this star.
Using it as a comparison star, we derive for the afterglow from a stack of
all images:
time after burst Rc dRc
1.020536 days 21.20 0.06
This is in good agreement with the slightly later measurement of Khamitov
et al. (GCN 7661) but significantly fainter than the magnitude reported by
Pandey et al. (GCN 7663) for an observation a few hours earlier.
Data analysis was delayed by access problems.
This message may be cited.
GCN Circular 7672
Subject
GRB 080430
Date
2008-05-03T18:14:17Z (17 years ago)
From
Francois Kugel at Obs.Chante-Perdix,04 Banon,Fr <fkugel@wanadoo.fr>
C.Rinner ; F.Kugel report:
May 02
We are continuing with the monitoring of the afterglow (Klotz et al. GCN
7646) with the TEL 0.5-m f/3 reflector
located at Observatoire Chante-Perdix - 04 Banon, France (A77 mpc
station, N43.9997 E5.6475)
The observations started at 20:21:42 (UT).36 unfiltered exposures of 120s were
carried out; although weak the source is still visible (SNR = 4.4) on an
addition of 28 exposuress (cloudy passages on the other images). Measured
magnitude = 20.6 two day after the burst.
Astrometry and magnitudes were measured with the USNO-SA2.0 catalogue.
More information and picture here :
http://pagesperso-orange.fr/fkometes/pages/GRB080430.html
GCN Circular 7671
Subject
GRB 080430
Date
2008-05-03T18:03:09Z (17 years ago)
From
Francois Kugel at Obs.Chante-Perdix,04 Banon,Fr <fkugel@wanadoo.fr>
C.Rinner ; F.Kugel report:
We are continuing with the monitoring of the afterglow (Klotz et al. GCN
7646) with the TEL 0.5-m f/3 reflector
located at Observatoire Chante-Perdix - 04 Banon, France (A77 mpc
station, N43.9997 E5.6475)
The observations started at 20:39:12 (UT).
9 unfiltered exposures of 120s were carried out and weather conditions
were good.
We observe a weak reduction in magnitude
RA(J2000.0) = 11h 01m 14.76s
DEC(J2000.0) +51d 41' 08.3"
�0.3"
magnitude = 19.6 �0.3 one day after the burst.
Astrometry and magnitudes were measured with the USNO-SA2.0 catalogue.
More information and picture here :
http://pagesperso-orange.fr/fkometes/pages/GRB080430.html
GCN Circular 7670
Subject
GRB 080430
Date
2008-05-03T17:54:03Z (17 years ago)
From
Francois Kugel at Obs.Chante-Perdix,04 Banon,Fr <fkugel@wanadoo.fr>
C.Rinner ; F.Kugel report:
We imaged the field of GRB 080430 detected by SWIFT
with the TEL 0.5-m f/3 reflector
located at Observatoire Chante-Perdix - 04 Banon, France (A77 mpc station)
The observations started at 21:33:18 (UT).
24 exposures of 120s were carried out and weather conditions
were good.
We observe a new source in the error box given by SWIFT
at the following position:
RA(J2000.0) = 11h 01m 14.76s
DEC(J2000.0) +51d 41' 08.3"
+/-0.3"
magnitude = 18.6 +/-0.3
Astrometry and magnitudes were measured with the USNO-SA2.0 catalogue.
No change magnitude was observed during the one hour observation.
More information and pictures here :
http://pagesperso-orange.fr/fkometes/pages/GRB080430.html
GCN Circular 7663
Subject
GRB 080430: Optical observations
Date
2008-05-02T08:33:59Z (17 years ago)
From
Shashi Bhushan Pandey at ARIES, INDIA <shashi@aries.ernet.in>
S. B. Pandey, Rupak Roy and Brijesh Kumar (ARIES, NainiTal, India, on behal=
f of larger Indian GRB collaboration)
We observed Swift GRB 080430 with 1.04m telescope NainiTal starting ~20.0 h=
ours after the burst (Guidorzi et al. GCN 7647). Observations were performe=
d in R_c and I_c filters.
Photometry of one of the R_c frame (exposure time 1800s) shows theafterglow=
around ~ 20.5 mag as reported in GCN 7646 and GCN 7648. The reported magni=
tude is determined in comparison to nearby USNO stars.
This message may be cited.
GCN Circular 7662
Subject
GRB 080430: Shallow decay
Date
2008-05-02T02:51:50Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), C.C. Th�ne (Dark), F. Aceituno (IAA-CSIC),
Nicolaas E. Groeneboom, �ystein Rudjord, Jostein R. Kristiansen (Univ.
Oslo)
and Tapio Purismo (NOT) on behalf of a larger collaboration report:
We are continuing with the monitoring of the afterglow (Klotz et al. GCN
7646)
of GRB 080430 (Guidorzi et al., GCN 7647) with the 1.5m OSN telescope
(Sierra
Nevada Observatory) and the 2.5m NOT+MOSCA (Roque de los Muchachos
Observatory) in I band. During the first day of observations we observe a
steady
decay with a shallow slope of alpha ~ 0.6 (f ~ t^-alpha), being at a
magnitude of
I ~ 20.5 one day after the burst.
Further observations are encouraged. This message can be cited.
GCN Circular 7661
Subject
GRB080430: RTT150 Optical Observations
Date
2008-05-02T00:18:18Z (17 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
I. Khamitov (TUG), I. Bikmaev, R. Gumerov,
A. Nemtinov, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
The optical counterpart (GCN7646) of GRB 080430 (GCN 7647) was observed
with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK
National Observatory, Turkey), starting at May 01, 21:58 UT, i.e.
~26.08 hours after the burst, using Andor CCD.
A series of frames 3*300s in R and 3*600s in B bands were made.
The afterglow is clearly detected in all images. Using USNO-B1 star
(416-022819, RA=11:01:16.86, DEC=+51:40:38.5, B2MAG=17.79, R2MAG=16.61)
we estimated the following magnitudes for the OT on combined images:
t-t0 (h) band mag err
26.25 R 21.3 0.1
27.98 B 22.3 0.1
--
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GCN Circular 7660
Subject
GRB080430: Swift/UVOT observations
Date
2008-05-01T21:49:40Z (17 years ago)
From
Wayne Landsman at GSFC/SSAI <wayne.b.landsman@nasa.gov>
W.B. Landsman (NASA/GSFC) and C. Guidorzi (INAF-OAB) report on behalf
of the Swift/UVOT team
The Swift/UVOT observed the field of GRB 080430 starting at 58s after
the BAT trigger (Guidorzi et al., GCN 7647). We detect the afterglow in
all seven UVOT filters at the position
RA(J2000.0) = 11:01:14.66
DEC(J2000.0) = +51:41:08.4
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This position is consistent with the enhanced XRT position (Guidorzi et
al. GCN 7653)
and the position reported from BOOTES obervations by Jelinek et al.
(GCN 7648). The detection in the UVW2 (1950 A) filter is consistent
with the
redshift of ~0.76 determined from spectroscopic observations by Deugarte
Postigo et al. (GCN 7650) and Cucchiara & Fox (GCN 7654). The temporal
slope in the white filter out to 30400 seconds is approximately alpha =
0.23.
UVOT photometry from early individual images is reported below.
Filter Tmid(s) Expo(s) Magnitude
-----------------------------------------------------
White 108 98 17.08 � 0.03
White 928 98 18.23 � 0.05
v 364 393 17.64 � 0.06
v 1184 393 18.50 � 0.09
b 5989 197 20.05 � 0.21
u 5784 197 18.92 � 0.12
w1 7014 197 18.89 � 0.16
m2 6809 197 18.88 � 0.22
w2 5684 197 19.24 � 0.20
-----------------------------------------------------
These magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E{B-V} = 0.012 mag (Schlegel et al.
1998). The photometry is on the UVOT flight system described in Poole
et al. (2008,MNRAS,383,627).
GCN Circular 7659
Subject
VLA radio upper limit on GRB 080430
Date
2008-05-01T21:31:39Z (17 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
080430 (GCN 7647) at a frequency of 8.46 GHz at 2008 May 1.17 UT.
We do not detect the GRB afterglow at the UVOT afterglow position (GCN 7647).
The flux density at the GRB afterglow position is 68 � 46 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 7658
Subject
GRB 080430 - multicolor observations of the afterglow
Date
2008-05-01T21:03:39Z (17 years ago)
From
Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr <cthoene@astro.ku.dk>
Christina C. Thoene (DARK), Johan P. U. Fynbo (DARK), Antonio de Ugarte
Postigo (ESO), D. Alexander Kann (TLS), Nicolaas E. Groeneboom, �ystein
Rudjord, Jostein R. Kristiansen (Univ. Oslo) and Tapio Purismo (NOT)
report:
We observed the afterglow (GCN 7646, Klotz et al.) of GRB 080430 (GCN
7647, Guidorzi et al.) with MOSCA at the NOT/La Palma on Apr. 30 starting
1.21h after the burst. Observations in UBVRI filters with exposure times
of 150s in each filter were acquired.
The afterglow is clearly detected in all bands and we derive the following
preliminary magnitudes based on the pre-burst SDSS calibrations (GCN 7649,
Cool et al.) and standard transformations between SDSS and Bessell
filters, times given are the start of the exposures.
t-t0(h) band mag
1.92 U 19.9 +- 0.2
1.74 B 19.8 +- 0.1
1.56 V 19.3 +- 0.1
1.21 R 19.0 +- 0.1
1.38 I 18.7 +- 0.1
The blue colors and the detection down to the U band are consistent with
the low redshift of that burst, z=0.767 as found by de Ugarte Postigo et
al. (GCN 7650) and Cucchiara et al. (GCN 7654).
GCN Circular 7657
Subject
GRB 080430 optical observations
Date
2008-05-01T16:35:47Z (17 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Arto Oksanen (Muurame, Finland) and Veli-Pekka Hentunen (Varkaus, Finland)
report to the AAVSO High Energy Network the following optical observations
of GRB 080430 (Guidorzi et al., GCN Circular #7647):
Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports the detection
of the optical counterpart of GRB 080430. Unfiltered observations were
made using a 0.4-meter RC telescope with an SBIG STL-1001E CCD. The
initial Swift XRT position was observed unfiltered with an initial set of
10 60-second exposures having a mid-point time of 2008 April 30, 20:08:54
UT; the afterglow was detected with a magnitude of 18.1 +/- 0.05
calibrated relative to GSC 3450-0639. Astrometry of the initial frames
yields a position of RA 11:01:14.76 , Dec +51:41:08.9 (USNOA2.0 ref, +/-
0.4 arcseconds), which is within the stated uncertainties of the UVOT
position (GCNCirc #7647).
Images taken between April 30.839 and April 30.969 UT were reanalyzed and
calibrated relative to two USNO-B1.0 stars of magnitude ~16.5. Photometry
of combined frames yields a smoothly decaying light curve during the span
of observations:
obs midpoint CR error
2008 April 30.839 17.798 0.088
2008 April 30.849 18.329 0.120
2008 April 30.860 18.484 0.087
2008 April 30.875 18.751 0.076
2008 April 30.893 18.868 0.055
2008 April 30.911 18.956 0.052
2008 April 30.929 19.044 0.067
2008 April 30.949 19.012 0.064
2008 April 30.969 19.156 0.076
A detailed report of the initial observations is available at the following URL:
ftp://ftp.aavso.org/grb/A.Oksanen_GRB080430_2454587.38588_.txt
A FITS image of this observation is available at the following URL:
ftp://ftp.aavso.org/grb/A.Oksanen_GRB080430_2454587.38588_.fits
Markku Nissinen and Veli-Pekka Hentunen (Taurus Hill Observatory, Varkaus,
Finland) also report the detection of the optical afterglow of GRB 080430.
Observations were made using a Meade LX-200 0.3-meter telescope with an
SBIG ST8-XME CCD; observations were made using both clear and R filters.
A total of six 600-second exposures were obtained having an average
midpoint time of 2008 April 30.943. Photometry of the combined clear and
Rc frames yields magnitudes of CR=19.2+/-0.3 and R=19.5+/-0.5 calibrated
relative to the GSC2.3 star N7JI005540. The observers noted the sky was
not completely dark due to their high latitude and time of year.
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
GCN Circular 7656
Subject
GRB 080430, Swift-BAT refined analysis
Date
2008-05-01T13:19:08Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
C. Guidorzi (INAF-OAB), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (GSFC/ISAS), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080430 (trigger #310613)
(Guidorzi, et al., GCN Circ. 7647). The BAT ground-calculated position is
RA, Dec = 165.331, 51.682 deg, which is
RA(J2000) = 11h 01m 19.4s
Dec(J2000) = +51d 40' 55.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a single FRED peak starting at ~T-0.7 sec,
peaking at ~T+1.5 sec, and ending at ~T+60 sec. T90 (15-350 keV) is
16.2 +- 2.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.3 to T+21.3 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.73 +- 0.09. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.70 sec in the 15-150 keV band
is 2.6 +- 0.2 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/310613/BA/
GCN Circular 7655
Subject
GRB080430: optical observations
Date
2008-05-01T12:01:37Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), Ju.
Babina (CrAO), V. Petkov, A. Kurenya (BNO INR RAS), A. Pozanenko (IKI) on
behalf of larger GRB follow up collaboration report:
We observed the afterglow (Klotz et al. GCN 7646, Guidorzi et al. GCN 7647,
Jelinek et al. GCN 7648) of GRB080430 (Guidorzi et al. GCN 7647) with
Zeiss-600 of Mt.Terskol observatory on Apr.30. The fading afterglow is
clearly detected in combined images. A photometry of the OT against
USNO-B1.0 stars is following:
UT, Exposure, R_mag
(mid time)
Apr.30.8906 15 x 60s 19.10 +/- 0.20
Apr.30.9014 15 x 60s 19.40 +/- 0.20
Apr.30.9130 15 x 60s 19.75 +/- 0.25
The message may be cited.
GCN Circular 7654
Subject
GRB 080430: Hobby-Eberly Telescope Absorption Redshift
Date
2008-05-01T10:47:05Z (17 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara and D. B. Fox (Penn State) report:
"Starting on 2008 May 1.21 UT we used the Marcario LRS spectrograph
on the Hobby-Eberly Telescope (R ~ 230) to obtain a 1200s spectrum
of the optical afterglow of GRB 080430 (Guidorzi et al., GCN 7647).
The spectrum covers the wavelength range 4100 to 10,500 Angstrom. We
clearly observe metal absorption features corresponding to the MgII
doublet (2796, 2803 A) and MgI (2852 A) at redshift z = 0.767. The
spectrum does not show any other significant features, consistent
with Calar Alto telescope observations (de Ugarte Postigo et al.,
GCN 7650).
We thank the HET staff for performing this observation."
GCN Circular 7653
Subject
GRB 080430: Swift-XRT refined analysis
Date
2008-05-01T10:25:39Z (17 years ago)
From
Cristiano Guidorzi at INAF-OAB <cristiano.guidorzi@brera.inaf.it>
C. Guidorzi, J. Mao (INAF-OAB), P. Evans and K.L. Page (Leicester)
report on behalf of the Swift-XRT team:
The Swift-XRT began observing GRB 080430 (trigger=310613, Guidorzi et
al., GCN Circ. 7647) in Window Timing mode, 55 s after the BAT
trigger. Using 2 ks of overlapping XRT and UVOT data, we can improve
the UVOT-enhanced XRT position given by Evans in al. (GCN Circ. 7652)
to RA, Dec = 165.31104, +51.68558 which is equivalent to:
RA (J2000): 11h 01m 14.65s
Dec (J2000): +51d 41' 08.1"
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
The light curve of the first five orbits, from 55 s to 24.7 ks,
totalling 10.3 ks of exposure, can be modelled with a double broken
power law with the following best-fitting parameters:
alpha_1=2.34+/-0.16, t_break1=309 (-33,+58) s, alpha_2=0.38+/-0.06,
t_break2=10.3 (-2.2,+3.8) ks, alpha_3=0.65+/-0.17 (chisq/dof=77/81).
The WT mode spectrum spanning from 55 to 138 s can be fit by an absorbed
power-law model, with a photon index of 2.42 (-0.14, +0.27) and column
density of 4.6(-2.6, +3.2)e20 cm^-2, which is in excess of the average
Galactic column density in this direction of 9.6e19 cm^-2.
The PC mode spectrum of orbits 2 to 5, spanning from 5.6 to 24.7 ks,
is fit with a higher column density, (2.0+/-0.4)e21 cm^-2 and
a power-law index of 2.3+/-0.2.
The corresponding observed (unabsorbed) 0.3-10 keV flux is 5.0e-12
(8.5e-12) erg cm^-2 s^-1.
If the burst continues to decay at the same rate, we predict an
XRT count rate of 3.8e-2 count/s at T+24 hours, which corresponds
to an observed 0.3-10 keV flux of approximately 1.7e-12 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 7652
Subject
GRB 080430: Enhanced Swift-XRT position
Date
2008-05-01T04:40:50Z (17 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 18 s of overlapping XRT Photon Counting mode and UVOT
data for GRB 080430, 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 = 165.31109, +51.68539 which is equivalent
to:
RA (J2000): 11h 01m 14.66s
Dec (J2000): +51d 41' 07.4"
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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 7651
Subject
GRB080430: Optical observation in AsU CAS Ondrejov & Brno
Date
2008-05-01T04:02:43Z (17 years ago)
From
Matus Kocka at Monteboo Obs,Masaryk U,Brno <koci@astronom.sk>
M. Kocka, M. Nekola, J. Strobl, R. Hudec, C. Polasek (AsU CAS - Ondrejov),
M. Jelinek, P. Kubanek (IAA-CSIC - Granada),
R. Novak (N. Copernicus Observatory - Brno)
F. Munz (IASF/INAF - Bologna)
The 0.5m D50 telescope in AsU CAS Ondrejov, Czech Republic observed
GRB080430. Observation started at 20:57:02 UT. After 29 x 20 sec
exposures we detected optical counterpart at the coordinates:
(J2000) 11:01:14.7 +51:41:08.6 (M. Jelinek & al; GCN CIRCULAR 7648)
Calibrated to near USNO et ESO star in R magnitude ~ 18.9mag (21:02:23
UT mid-time of exposure)
http://physics.muni.cz/~koci/GRB080430/grb080430.jpg
The 0.4m N. Copernicus Observatory telescope at Brno Czech Republic also
observed
same coordinates with the same results.
http://ccder.blogspot.com/
Further analysis is in progress
This message may be cited.
GCN Circular 7650
Subject
GRB 080430: Spectroscopy from CAHA
Date
2008-05-01T02:51:20Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo, L. Christensen (ESO), J. Gorosabel (IAA-CSIC),
C. Th�ne (Dark), D.A. Kann (TLS), A. Mora (UAM), T. Szeifert (ESO),
M. Jelinek, A.J. Castro-Tirado (IAA-CSIC), S. Pedraz (CAHA),
N. Cardiel, D. Montes (UCM). On behalf of a larger collaboration report:
We have obtained spectroscopic observations of GRB 080430 from the 2.2m
Calar
Alto telescope (+CAFOS) starting at 21:11 UT (78 minutes after the
burst). The
observations consisted of 3x1200s integrations in low resolution. The
signal to noise
ratio is low but after a preliminary reduction we may conclude:
1) Continuum is clearly detected down to 3500 Angstroms, implying a
redshift smaller
than 1.9.
2) We detect an absorption feature at ~4900 Angstroms that we suggest to
be the
MgII doublet (2796.3, 2803.5), implying a most probable redshift of ~0.75.
Further analysis is ongoing. Additional spectroscopic observations are
encouraged.
This message may be cited.
GCN Circular 7649
Subject
GRB 080430 - SDSS Pre-Burst Observations
Date
2008-04-30T20:36:36Z (17 years ago)
From
Richard J. Cool at U.of AZ/Steward Obs <rcool@as.arizona.edu>
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona),
David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel
(LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald
P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst
GRB080430 prior to the burst. As these data should be useful
as a pre-burst comparison and for calibrating photometry,
we are supplying the images and photometry measurements for
this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and
3 files of photometry and astrometry, are being placed at
http://mizar.as.arizona.edu/~grb/public/GRB080430
We supply FITS images in each of the 5 SDSS bands of a 8'x8'
region centered on the GRB position (ra=165.322 (11:01:17.3),
dec=51.6890 (51:41:20.4); Swift-BAT TRIGGER 310613), as well
as 3 gri color-composite JPGs (with different stretches). The
units in the FITS images are nanomaggies per pixel. A pixel
is 0.396 arcsec on a side. A nanomaggie is a flux-density unit
equal to 10^-9 of a magnitude 0 source or, to the extent that
SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS
astrometric information.
In the file GRB080430_sdss.calstar.dat, we report photometry
and astrometry of 193 bright stars (r<20.5) within 15' of the
burst location. The magnitudes presented in this file are asinh
magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118,
1406). Beware that some of these stars are not well-detected
in the u-band; use the errors and object flags to monitor
data quality.
In the files GRB080430_sdss.objects_flux.dat and
GRB080430_sdss.objects_magnitudes.dat, we report photometry
of 582 objects detected within 6' of the GRB position.
We have removed saturated objects and objects with model
magnitudes fainter than 23.0 in the r-band. The fluxes listed
in GRB080430_sdss.objects_flux.dat are in nanomaggies while
the magnitudes listed in GRB080430_sdss.objects_magnitudes.dat
are asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning
that they are very close to AB zeropoints and magnitudes are
quoted in asinh magnitudes. Photometric zeropoints are known
to about 2% rms. None of the photometry is corrected for
dust extinction. The Schlegel, Finkbeiner, and Davis (1998)
predictions for this region are A_U=0.061 mag, A_g=0.045 mag,
A_r = 0.032 mag, A_i=0.025 mag, and A_z=0.017 mag.
There are currently no objects within 6 arcminutes of the GRB
position in the SDSS spectroscopic database.
SDSS astrometry is generally better than 0.1 arcsecond per
coordinate. Users requiring high precision astrometry should
take note that the SDSS astrometric system can differ from
other systems such as those used in other notices; we have
not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases
can be found in our initial data release paper (Cool et
al. 2006, PASP 118, 733). See the SDSS DR4 documentation for
more details: http://www.sdss.org/dr5.
These data have been reduced using a slightly different
pipeline than that used for SDSS public data releases.
We cannot guarantee that the values here will exactly match
those in the data release in which these data are included.
In particular, we expect the photometric calibrations to differ
by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data
release paper, Adelman-McCarthy et al. (2007, ApJS, 172, 634),
when using the data or referring to the technical documentation.
GCN Circular 7648
Subject
GRB 080430: Bootes observation
Date
2008-04-30T20:21:25Z (17 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
M. Jelinek, P. Kubanek, J. Gorosabel, A. J. Castro-Tirado, F.
Aceituno (IAA-CSIC Granada), L. Sabau-Graziati (INTA Madrid),
A. de Ugarte Postigo (ESO Santiago), R. Hudec (ASU-CAS
Ondrejov), P. Perez-Gonzalez and J. Zamorano (UCM Madrid)
report on behalf of a larger collaboration:
The BOOTES-1 0.3m telescope in South Spain observed GRB
080413A, starting at 19:53:36 UT (34 sec after the GRB). A
sequence of preprogrammed 6 sec, 20 and 60 sec exposures was
obtained. We find an optical counterpart at the coordinates
(J2000)
11:01:14.777 +51:41:08.61
with an unfiltered magnitude ~17.0 at ~60s after the GRB.
We continue observing the object with the 1.5m telescope at
Observatorio Sierra Nevada, which confirms the reality of the
object.
--
Martin Jelinek, +420602105255, +34617840945, sirrah.cz/mates
Instituto de Astrofisica de Andalucia, Granada
# vim:set ai et sts=8 tw=60:
GCN Circular 7647
Subject
GRB 080430: Swift detection of a burst with optical afterglow
Date
2008-04-30T20:16:10Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
C. Guidorzi (INAF-OAB), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
O. Godet (U Leicester), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
W.L Landsman (GSFC), C. B. Markwardt (CRESST/GSFC/UMD),
K. M. McLean (GSFC/UMD), P. T. O'Brien (U Leicester),
D. M. Palmer (LANL), D. Perez (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB),
T. N. Ukwatta (GSFC/GWU), D. E. Vanden Berk (PSU) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 19:53:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080430 (trigger=310613). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 165.322, +51.689 which is
RA(J2000) = 11h 01m 17s
Dec(J2000) = +51d 41' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single FRED peak
structure with a duration of about 20 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 19:53:50.9 UT, 48.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
165.31041, 51.68546 which is equivalent to:
RA(J2000) = 11h 01m 14.50s
Dec(J2000) = +51d 41' 07.7"
with an uncertainty of 2.7 arcseconds (radius, 90% containment). This
location is 28 arcseconds from the BAT onboard position, within the BAT
error circle.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (9.59e+19
cm^-2, Kalberla et al. 2005), with an excess column of 3 (+1.33/-1.17)
x 10^21 cm^-2 (90% confidence). The relation of Grupe et al. (2007)
implies that this burst has a redshift z<3.5, although high redshift
fits to the absorbed XRT spectrum are possible if paired with an
anomalously large column. A summary of the promptly downlinked data is
given at http://www.swift.ac.uk/sper/310613/.
The initial flux in the 2.5 s image was 1.26e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 400 seconds with the v filter starting
164 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 11:01:14.71 = 165.3113
DEC(J2000) = +51:41:08.5 = 51.6857
with a 1-sigma error radius of about 0.5 arc sec. This position is 2.2 arc sec.
from the center of the XRT error circle. The estimated magnitude is 17.6 with a
1-sigma error of about 0.5 mag. A white filter finding chart exposure was also
taken before the v filter, showing that the afterglow is fading. No correction
has been made for the expected extinction of about 0.04 magnitudes.
Burst Advocate for this burst is C. Guidorzi (cristiano.guidorzi 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 7646
Subject
GRB 080430: TAROT Calern observatory optical observations
Date
2008-04-30T20:09:33Z (17 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 080430 detected by SWIFT
(trigger 310613) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 18.8s after the GRB trigger
(7.2s after the notice). The elevation of the field increased from
from 82 degrees above horizon and weather conditions
were good.
We detect a new fading source in the error box given by SWIFT
at the following position (+/- 3 arcsec):
RA(J2000.0) = 11h 01m 14.2s
DEC(J2000.0) +51d 41' 08"
OT was R~16 at 18.8s after GRB.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=155.5591 lat=+57.8882
and the galactic extinction in R band is 0.0 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.
51�41'08"