GRB 060927
GCN Circular 5627
Subject
GRB 060927: Swift detection of a burst
Date
2006-09-27T14:35:47Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
L. M. Barbier (NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), P. J. Brown (PSU),
D. N. Burrows (PSU), S. Campana (INAF-OAB), M.L. Conciatore (ASDC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB),
S. T. Holland (GSFC/USRA), S. D. Hunsberger (PSU),
J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA),
V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC),
K. M. McLean (LANL/UTD), C. Pagani (PSU), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-OAB), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester), E. Troja (INAF-IASFPA) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 14:07:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060927 (trigger=231362). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA,Dec 329.553, +5.353 {21h 58m 13s, +5d 21' 10"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). There was a data dropout and we did not get
the TDRSS lightcurve. However, we are confident that this is a real GRB
because of the very high detection significance and the 0.25-sec trigger
criteria.
The XRT began taking data at 14:08:40 UT, 65 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in the
image, however analysis of prompt downlinked data from this burst reveals a
fading point source at the following location:
RA(J2000) = 21h 58m 12.3s
Dec(J2000) = +05d 21m 53.5s
with an estimated uncertainty of 6 arcseconds radius (90% containment). This
position lies 43 arcseconds from the BAT position.
UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 71 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
overlap of the 2.7' x 2.7' region for the finding chart and the XRT error
circle is 100%. The limiting magnitude of the finding chart image is
approximately 19.0. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.06.
We are currently in the Malindi gap and will not have event data
analyzed for 6 hours. We note that there is a galaxy in the APM-North
catalog that is 6.7 arcsec from the XRT position. It is B=22, R=20
and has a 5 arcsec major axis diameter.
GCN Circular 5630
Subject
GRB 060927: optical afterglow confirmation
Date
2006-09-27T15:30:43Z (19 years ago)
From
Ken ichi Torii at Osaka U <torii@ess.sci.osaka-u.ac.jp>
K. Torii (Osaka U.) reports on behalf of the ART collaboration:
The error region of GRB 060927 (Barbier et al. GCN 5627) was observed
with the 14 inch ART-3a and 0.35m ART-3b in Toyonaka, Osaka.
Preliminary analysis of the ART-3a data confirms the presence of a
fading source at the position consistent with that reported by
Schaefer et al. (GCN 5629).
===
GCN Circular 5631
Subject
GRB060927 - SDSS Pre-Burst Observations
Date
2006-09-27T15:44:46Z (19 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
GRB060927 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/GRB060927
We supply FITS images in each of the 5 SDSS bands of a 8'x8'
region centered on the GRB position (ra=329.553 (21:58:12.7),
dec=5.35300 (05:21:10.8); Swift-BAT TRIGGER 231362), 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 GRB060927_sdss.calstar.dat, we report photometry
and astrometry of 435 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 GRB060927_sdss.objects_flux.dat and
GRB060927_sdss.objects_magnitudes.dat, we report photometry of
993 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
GRB060927_sdss.objects_flux.dat are in nanomaggies while the
magnitudes listed in GRB060927_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=0.324 mag, A_g=0.239 mag, A_r = 0.173 mag, A_i=0.131
mag, and A_z=0.093 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,
astro-ph/0601218). 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. (2006, ApJS, 162, 38), when using
the data or referring to the technical documentation.
GCN Circular 5633
Subject
GRB060927: Faulkes Telescope South observation
Date
2006-09-27T15:55:29Z (19 years ago)
From
Cristiano Guidorzi at INAF-OAB <cristiano.guidorzi@brera.inaf.it>
C. Guidorzi (Univ Bicocca & INAF-OAB), D. Bersier (Liverpool JMU),
A. Melandri, A. Gomboc (University of Ljubljana), I.A. Steele, R.J. Smith,
C.G. Mundell, A. Monfardini, D. Carter, S. Kobayashi, M. Bode
(Liverpool JMU), P. O'Brien, E. Rol, N. Bannister (Leicester)
report:
The 2m Faulkes Telescope South (Siding Spring, Australia) automatically
reacted to the Swift burst GRB 060927 (trigger 231362, Barbier et al.,
GCN Circ. 5627) and began observing 1.78 minutes after the burst trigger
time.
We find an uncatalogued source in a 220s i'-band stacked image from
5.42 min to 20.35 min after the trigger time, lying 6.4" away from the
XRT centroid and 1.7" away from the ROTSE-III candidate (Schaefer et
al., GCN Circ. 5629):
RA(J2000) = 21:58:12.0
Dec(J2000)= +05:21:49
We estimate i'=18.0 +- 0.5 and from a 390s R-band image we derive R>18.
This source lies 6.4" from the APM galaxy mentioned by Barbier et al.
(GCN Circ. 5627).
Further observations are going on.
This message can be cited.
GCN Circular 5634
Subject
GRB 060927 : Kiso optical observation
Date
2006-09-27T16:03:53Z (19 years ago)
From
Yuji Urata at Saitama U <urata@crystal.heal.phy.saitama-u.ac.jp>
Y. Sarugaku, N. Miura (Tokyo Univ), Z.W. Zheng (NAOC), K.Y. Huang (NCU)
and Y. Urata (Saitama U/ NCU) on behalf of EAFON report:
"We have observed the XRT error region of GRB 060927 using Kiso 1.05m
Schmit telescope. The observation was started at 14:27 (about 20 min
after the burst). The optical afterglow is marginally detected in our
R band images taken with 90 sec exposure. The brightness in R band
derived by USNO-B1.0 catalog is 19.5 +/- 0.3.
Further observations and analysis are progress."
This message can be cited.
GCN Circular 5635
Subject
GRB 060927: Possible host galaxy (star?) in the SDSS
Date
2006-09-27T16:15:49Z (19 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann (TLS Tautenburg) reports:
There is a faint object visible in the SDSS r' band image (Cool
et al., GCN 5631) at position:
RA = 21:58:11.95 (329.54981)
Dec = +05:21:51.34 (5.36426)
It has model magnitudes:
u' = 24.114 +/- 0.976
g' = 24.414 +/- 0.497
r' = 22.915 +/- 0.216
i' = 23.009 +/- 0.345
z' = 21.672 +/- 0.426
This is very close to the afterglow location determined by
Schaefer et al. (GCN 5629) and Guidorzi et al. (GCN 5633) and
closer than the APM galaxy mentioned by Barbier et al. (GCN
5627).
The object is listed a being a star in the SDSS object table, but
it could also be a very compact host galaxy. If it is a star,
special care must be taken when undertaking deep photometry.
This message may be cited.
GCN Circular 5636
Subject
GRB 060927, optical observation
Date
2006-09-27T16:24:56Z (19 years ago)
From
Shouta Maeno at U.of Miyazaki <shouta@astro.miyazaki-u.ac.jp>
E.Sonoda, S.Maeno, K.Tanaka, H.Tanaka, T.Matsumura, M.Yamauchi
(University of Miyazaki)
We have observed the field covering the error circle of
GRB 060927 (GCN 5627) with the unfiltered CCD camera on
the 30-cm telescope at University of Miyazaki.
The observation was started from 14:08:07 UT on Sep. 27.
The weather condition was cloudy.
We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog, there is no new source
at the position reported by B.E.Schaefer et al.(GCN5629)
The upper limit is as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
14:08:07 14:08:37 1 ~15.6
14:11:54 14:32:44 9 ~16.9
---------------------------------------------------------------
GCN Circular 5638
Subject
GRB 060927: Xinglong TNT optical observations
Date
2006-09-27T17:47:44Z (19 years ago)
From
W.K. Zheng at NAOC <zwk@bao.ac.cn>
M.Zhai, L.P. Xing, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng
Y. Urata and W.K. Zheng on behalf of EAFON report:
We have imaged the field of GRB 060927 with the TNT 0.8m telescope
at Xinglong Observatory.The first image was taken at 14:09:06UT, 91s
after the burst. A series of White and R band images were obtained. The
optical afterglow is detected in out early 19*20s combined White image.
We estimated the mag ~19.8 +/- 0.4 with mean time 320s after the burst
derived from USNO A2.0
This message may be cited.
GCN Circular 5639
Subject
GRB 060927, Swift-BAT refined analysis
Date
2006-09-27T22:40:03Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/ISAS), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-240 to T+362 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 060927 (trigger #231362)
(Barbier, et al., GCN Circ. 5627). The BAT ground-calculated position
is RA,Dec = 329.547, 5.369 deg {21h 58m 11.3s, 5d 22' 9.4"} (J2000) +- 0.8 arcmin,
(radius, sys+stat, 90% containment). The partial coding was 82%.
The masked-weighted lightcurves starts with two overlapping peaks at T-2 sec,
and returning to background at T+9 sec. The third peak starts at T+15 sec
and ends at T+24 sec. T90 (15-350 keV) is 22.6 +- 0.3 sec (estimated error
including systematics).
The time-averaged spectrum from T-1.0 to T+23.8 is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.93 +- 0.38,
and Epeak of 71.7 +- 17.6 keV (chi squared 64.6 for 56 d.o.f.).
For this model the total fluence in the 15-150 keV band is
1.1 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured
from T+0.17 sec in the 15-150 keV band is 2.8 +- 0.2 ph/cm2/sec.
A fit to a simple power law gives a photon index of 1.65 +- 0.08
(chi squared 77.5 for 57 d.o.f.). All the quoted errors are at the 90%
confidence level.
GCN Circular 5640
Subject
GRB 060927 optical limit
Date
2006-09-27T23:03:03Z (19 years ago)
From
Graziella Pizzichini at IASF/CNR,Bologna <pizzichini@iasfbo.inaf.it>
G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna
University), F. Terra, Second University of Roma "Tor Vergata",
D. Nanni (INAF/OAR and Second University of Roma "Tor Vergata"),
S. Galleti, R. Gualandi (INAF Bologna) and G. Pizzichini (INAF/IASF
Bologna) report:
Using the 152 cm Loiano telescope equipped with the BFOSC camera
system, we obtained three 20 min. Rc-band images of the field of
GRB060927 (Barbier et al., GCN 5627), starting at Sept. 27.763 ,
27.779 and 27.795 respectively, seeing 2.2 arcsec.
In our co-added images we do not detect the OT reported by Schaefer,
Yost and Yuan (GCN 5629). Our 3 sigma upper limit is Rc = 21.7 .
GCN Circular 5641
Subject
GRB 060927: Swift XRT Team refined analysis
Date
2006-09-27T23:19:06Z (19 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
E. Troja (INAF-IASFPa), K. L. Page (U. Leicester), D. Burrows (PSU) and L.
M. Barbier (NASA/GSFC) report on behalf of the Swift/XRT team:
We have analysed the first three orbits of Swift data of GRB 060927
(Barbier et al., GCN 5627). The XRT data set consists of 4 ks in Photon
Counting mode (PC).
We derived a refined XRT position of
RA(J2000) = 21h 58m 12.2s
Dec(J2000) = +05d 21' 52.2''
with an error of 6" (90% confidence, including boresight uncertainties).
This position is within 1.8" of the initial XRT position, and 4.6" from
the optical afterglow candidate, reported in GCN 5629 (Schaefer et al.).
The lightcurve shows a break at 4 ks after the trigger. The decay before
the break is 0.7 steepening to 1.4 at later times. The spectrum can be
modelled with an absorbed power-law with a spectral index of 1.96+/-0.2
and a column density of 8+/-3 e20 cm^-2. The Galactic absorption in this
direction is 5.2e20 cm^-2.
The average unabsorbed flux for the first three orbits is 5.6e-12 ergs
cm^-2 s^-1. At this decay rate we predict a count rate of 1.2e-3 cts/s at
T+24h, corresponding to an unabsorbed flux of 7.2e-14 ergs cm^-2 s^-1.
This circular is an official product of the Swift XRT Team.
GCN Circular 5642
Subject
GRB 060927: Early color
Date
2006-09-28T03:53:36Z (19 years ago)
From
Ken ichi Torii at Osaka U <torii@ess.sci.osaka-u.ac.jp>
K. Torii (Osaka U.) reports on behalf of the ART collaboration:
As we reported in GCN 5630, the error region of GRB 060927 (Barbier
et al. GCN 5627) was observed with the 14 inch ART-3a (from 53 s after
the burst in Ic band) and 0.35m ART-3b (from 112 s after the burst in
Rc band) simultaneously.
The optical afterglow (Schaefer et al. GCN 5629) was detected in the
Ic band frames (Ic ~ 16.0 in the first 60 s exposure), but it was not
detected in single Rc band frames.
Combining our measurements and those reported in the circulars
(GCN 5629; Zhai et al. GCN 5638), we roughly estimate the early Rc-Ic
color redder (larger) than 1.5 and probably Rc-Ic ~ 2.0 at 100 s after
the trigger time. This early color is consistent with that derived
from later measurements at t ~ 300-1200 s (Guidorzi et al. GCN 5633;
Sarugaku et al. GCN 5634; GCN 5638). The non detection in the UVOT
white filter (GCN 5629) also suggests that the afterglow was red at t ~
100 s.
===
GCN Circular 5643
Subject
GRB 060927: Swift/UVOT Optical Observations
Date
2006-09-28T11:14:17Z (19 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S.R. Oates (UCL-MSSL), L.M. Barbier (GSFC) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began observing the field of GRB 0609027 at
14:08:45 on 2006-09-27, 51s after the BAT trigger (Barbier
et al., GCN 5627). No new source was detected within the XRT
error circle in the V band 10s settling exposure or in coadded
images in any filter down to the following 3-sigma magnitude upper
limits:
Filter Start End Exposure 3-sigma UL
-------------------------------------------------------------------
V 51 60 10 18.0
V 175 10273 1302 19.73
B 4197 5829 393 20.93
U 3992 5624 393 20.52
UVW1 3788 11355 561 21.44
UVM2 3583 11177 1279 20.42
UVW2 4606 6182 338 19.84
WHITE 70 6033 491 19.65
-------------------------------------------------------------------
These upper limits are not corrected for Galactic extinction
E(B-V) = 0.062.
GCN Circular 5644
Subject
GRB 060927: pseudo-z from spectral parameters of the prompt emission
Date
2006-09-28T14:40:47Z (19 years ago)
From
Alexandre Pelangeon at LATT,OMP,Toulouse <apelange@ast.obs-mip.fr>
A. Pelangeon & J-L. Atteia (LATT-OMP) report:
We have used the spectral parameters of GRB 060927
provided by Stamatikos et al. (GCNC 5639) to
compute the spectral pseudo-redshift** of this burst
detected by SWIFT-BAT (Barbier et al., GCNC 5627).
We find a pseudo-redshift pz= 2.37 � 0.75
** cf. http://www.ast.obs-mip.fr/grb/pz
GCN Circular 5647
Subject
GRB060927: optical observations
Date
2006-09-28T16:06:09Z (19 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
K. Antoniuk, V. Rumyantsev (CrAO), A. Pozanenko (IKI) on behalf of larger
GRB follow up collaboration report:
We observed the error box of GRB060927 (Barbier et al., GCN 5627) with
AZT-11 (1.25m) telescope of CrAO observatory between Sep. 27 (UT) 17:38:49
and 18:21:35. The OT (Schaefer et al., GCN5629) is clearly detected in a
combined image. A preliminary photometry against USNOA2.0 star (RA 21 58
12.96 Dec +05 22 31.40 18.60R) is following:
Mid time (UT), Exposure, R_mag
Sep. 27.750 15x180 s 21.4 +/- 0.3
The message may be cited.
GCN Circular 5651
Subject
GRB 060927: Spectroscopic redshift z=5.6
Date
2006-09-29T10:30:08Z (19 years ago)
Edited On
2024-11-18T09:52:12Z (7 months ago)
From
Brian Lindgren Jensen at U.of Copenhagen <brian_j@astro.ku.dk>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Johan P. U. Fynbo (DARK Cosmology Centre), Pall Jakobsson (U. of
Hertfordshire), Brian L. Jensen, Jens Hjorth, Jesper Sollerman,
Darach Watson, José María Castro Cerón (DARK Cosmology Centre),
Paul Vreeswijk (ESO), Michael I. Andersen (Potsdam) report on
behalf of a larger collaboration:
"Using FORS1 on the ESO Very Large Telescope we obtained a 3x30 min
spectrum of the afterglow of GRB 060927 (GCNs #5627, 5629) on Sep 28.1.
We detect a sharp continuum break at 8070 A which we interpret as the
onset of the Lyman-alpha forest. Hence the redshift of GRB 060927 is
z=5.6.
We have placed a finding chart and an image of the 2d-spectrum here:
http://www.astro.ku.dk/~brian_j/grb/grb060927.589/
We thank the Paranal staff for excellent support."
GCN Circular 5664
Subject
GRB 060927 : GAO 150cm telescope optical observation
Date
2006-09-30T04:41:01Z (19 years ago)
From
Kenzo Kinugasa at Gunma Astro. Obs/Japan <kinugasa@astron.pref.gunma.jp>
K. Kinugasa (Gunma Astronomical Observatory) and K. Torii (Osaka U.) report:
The error region of GRB 060927 (Barbier et al., GCN 5627) was imaged by
the LN2 cooled CCD camera atattched on the 150 cm telescope of the Gunma
Astronomical Observatory. Starting at Sep.27 14:44:33 UT (37 min after
the burst), thirty 30 s exposures in Rc band were obtained.
In a stacked frame, the optical afterglow (Schaefer et al. GCN 5629) is
detected and the magnitude is rouly estimated as follows relative to
USNO-B1.0 R2 magnitude.
------------------------
MidUT Filter Mag
------------------------
14:56 Rc ~20.3
------------------------
GCN Circular 6099
Subject
GRB 060927: PROMPT Observations
Date
2007-02-12T17:04:16Z (18 years ago)
From
Seth Johnson at U.North Carolina <spjohnso@physics.unc.edu>
S. Johnson, J. Haislip, D. Reichart, M. Nysewander, A. LaCluyze, K.
Ivarsen, J. A. Crain, A. Foster, and A. Trotter report:
Skynet observed the localization of z = 5.6 (Fynbo et al., GCN 5651) GRB
060927 (Barbier et al., GCN 5627) with four of the 16" PROMPT telescopes at
CTIO beginning 9.8 hours after the burst in Ugriz.
We do not detect the afterglow (Schaefer et al., GCN 5629) to 3-sigma
limiting magnitudes of z = 20.4 mag at a mean time of 12.1 hours after the
burst, i = 21.2 mag at 15.1 hours, and r = 21.7 mag at 14.7 hours.