GRB 100518A
GCN Circular 10772
Subject
GRB 100518A: a long GRB detected with INTEGRAL
Date
2010-05-18T12:32:27Z (15 years ago)
From
Sandro Mereghetti at IASF/CNR <sandro@iasf-milano.inaf.it>
S.Mereghetti, A. Paizis (IASF- Milano), D.Gotz (CEA-Saclay), E. Bozzo,
C.Ferrigno, P. Bordas, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK,
Torun) on behalf of the IBAS Localization Team report:
a long gamma ray burst has been detected by IBAS in the IBIS/ISGRI data at
11:33:35 U.T. on May 18th. It has a FRED light curve lasting about 30 s.
Its refined coordinates (J2000) are:
R.A.: 304.7999 [deg]
DEC.: -24.5609 [deg]
with an uncertainty of 1.6 arcmin (90% c.l.).
A preliminary analysis gives a peak flux in the 20-200 keV range of about
0.5 ph/cmsq/s (1 s integration time) and a fluence over the same energy
range of about 5 10e-7 erg/cmsq.
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.
GCN Circular 10775
Subject
GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
Date
2010-05-18T14:35:35Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), M. M. Chester (PSU),
P. A. Evans (U Leicester), J. M. Gelbord (PSU), J. A. Kennea (PSU),
C. Pagani (U Leicester), J. L. Racusin (NASA/GSFC) and L. Vetere (PSU)
report on behalf of the Swift Team:
Swift began a target of opportunity observation of GRB 100518A on May
18, 2010 at 14:10 UT, approximately 2.6 hours after the burst was
detected by INTEGRAL. Swift data for these observations utilize Target
ID 20138.
The XRT began observing the field at 14:12:42.5 UT, 9.5 ks after the
INTEGRAL trigger. Using promptly downlinked data we find an
uncatalogued X-ray source located at RA, Dec 304.78875, -24.55459 which
is equivalent to:
RA(J2000) = 20h 19m 9.30s
Dec(J2000) = -24d 33' 16.5"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 42 arcseconds from the INTEGRAL position, within the
INTEGRAL error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. We cannot determine whether the source is
fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
6.4e+20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 9551 seconds after the INTEGRAL trigger. No credible
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical
3-sigma upper limit has been about 19.6 mag. The 8'x8' region for
the list of sources generated on-board is typically complete to about
18 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.07.
Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov).
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 10776
Subject
GRB 100518A: Faulkes Telescope North Afterglow Candidate
Date
2010-05-18T15:00:48Z (15 years ago)
From
Zach Cano at ARI/John Moores Liverpool <zec@astro.livjm.ac.uk>
Z. Cano (Liverpool JMU), A. Gomboc (U. Ljubljana), C. Guidorzi (U.
Ferrara) report on behalf of a larger collaboration:
On 2010 May 18 at 11:37:46 UT the 2-m Faulkes Telescope North
automatically began observing the INTEGRAL GRB 100518A (Mereghetti et al.,
GCN 10772).
The LT-TRAP automatically detected a fading object in R and i at the
following position:
Ra: 20:19:09.33
Dec: -24:33:16.50 (J2000)
This lies 0.4 arcseconds from the XRT centroid (Stamatikos et al., GCN
10775).
GCN Circular 10778
Subject
GRB 100518A: BOOTES-3 optical observations
Date
2010-05-19T08:44:42Z (15 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (INAF-OAB), A.J. Castro-Tirado, J. Gorosabel,
M. Jelinek (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC),
R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock (Auckland Univ.),
W.H. Allen (Vintage Lane Obs.), I. Bond (Massey Univ.), G. Christie
(Stardome Obs.) report on behalf of a larger collaboration:
"We have observed the field of the INTEGRAL GRB 100518A
(Mereghetti et al., GCN 10772) using the 0.6m Yock-Allen robotic
telescope (BOOTES-3) located in Blenheim, New Zealand.
Preliminary analysis of a combined 40x60s unfiltered exposure
taken (mid-epoch) on 18th May 2010, 14:01 UT (2.47 hours after
the burst, when acceptable weather allowed to perform the
observations) does not show any source at the position of the
optical afterglow candidate (Cano et al., GCN 10776) down to a
3-sigma limiting magnitude of R ~ 20.7 using USNO-B1.0 as
photometric reference."
GCN Circular 10779
Subject
GRB 100518A: optical afterglow decay
Date
2010-05-19T09:04:53Z (15 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
D. Kopac (U. Ljubljana), C. Guidorzi (U. Ferrara), Z. Cano (Liverpool JMU),
A. Gomboc (U. Ljubljana), report on behalf of a larger collaboration:
The 2-m Faulkes Telescope North observed the optical afterglow of
GRB 100518A (Cano et al. GCN Circ. 10776) from 4.2 min to 3.7 hours from
the INTEGRAL trigger time (Mereghetti et al. GCN Circ. 10772) in
the BVRi filters.
Within this time interval the afterglow is observed to decay in both
R and i filters with an average power-law decay slope of 0.7 +/- 0.1,
with the following initial magnitudes:
Mid time from Total Exp Filter Magnitude
trigger (min) (s)
-------------------------------------------------
4.9 3x10 R 19.4 +- 0.1
9.8 10 i 18.8 +- 0.2
-------------------------------------------------
Magnitudes have been calibrated from nearby USNOB-1 stars.
GCN Circular 10780
Subject
GRB 100518A: Swift-XRT refined analysis
Date
2010-05-19T09:13:34Z (15 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A. P. Beardmore, R. L. C. Starling, P. A. Evans (U. Leicester) and
M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift-XRT team:
We have analysed 4.7 ks of XRT data for the INTEGRAL triggered GRB
100518A (Mereghetti et al. GCN Circ. 10772, Stamatikos et al. GCN
Circ. 10775), from 9.6 ks to 17.9 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. Using 2.4 ks of PC mode
data and 3 UVOT images 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 = 304.78931, -24.55436 which is
equivalent to:
RA (J2000): 20h 19m 9.43s
Dec (J2000): -24d 33' 15.7"
with an uncertainty of 2.2 arcsec (radius, 90% confidence). Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and
Evans et al. (2009, MNRAS, 397, 1177).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.68 +1.00 -0.96.
A spectrum formed from the entire PC mode dataset can be fitted with
an absorbed power-law with a photon spectral index of 3.6 +1.4 -0.7.
The best-fitting absorption column is (4.5 +3.5 -3.3) x 10^21 cm^-2,
in excess of the Galactic value of 6.4 x 10^20 cm^-2 in the direction
of the burst (Kalberla et al. 2005). The observed (unabsorbed) 0.3-10
keV flux for this spectrum is 6.1 x 10^-13 (5.4 x 10^-12) erg cm^-2
s^-1, resulting in a counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor of 2.7 x 10^-11 (2.4 x 10^-10) erg cm^-2 count^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020138.
This circular is an official product of the Swift-XRT team.
GCN Circular 10781
Subject
GRB 100518A: Swift/UVOT Upper Limits
Date
2010-05-19T11:00:50Z (15 years ago)
From
Peter Curran at MSSL <pac@mssl.ucl.ac.uk>
P.A. Curran (MSSL-UCL) and M. Stamatikos (OSU/NASA/GSFC) report on
behalf of the Swift/UVOT team:
During Swift target of opportunity observations of GRB 100518A
(Stamatikos et al. GCN Circ. 10775), Swift/UVOT began settled
observations starting 9551 seconds after the INTEGRAL trigger
(Mereghetti et al. GCN Circ. 10772). No optical afterglow consistent
with the enhanced XRT position (Beardmore et al. GCN Circ. 10780) or the
optical counterpart (Cano et al. GCN Circ. 10776) is detected in the
UVOT exposures. Preliminary 3-sigma upper limits using the UVOT
photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
------------------------------------------------
white 9551 9701 147 >21.4 (FC)
white 9551 11529 1033 >22.4
v 16324 17231 885 >20.7
b 9711 10618 885 >21.7
m2 17236 17899 652 >20.9
w2 11536 16318 1137 >21.6
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 10782
Subject
GRB 100518A: GROND afterglow observation and photo-z
Date
2010-05-19T15:28:57Z (15 years ago)
From
Thomas Kruehler at MPE/MPI <kruehler@mpe.mpg.de>
P. Afonso, P. Schady, T. Kruehler and J. Greiner (all MPE Garching)
report on behalf of the GROND team:
We observed the field of GRB 100518A (Mereghetti et al., GCN 10772)
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120,
405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 09:12 UT on May 19, 21.7 hours after the GRB
trigger, and continued for 1 hour.
In stacked images of 50 min total integration time in g'r'i'z' we detect
the optical afterglow (Cano et al., GCN 10776) in r'i' and z'.
Preliminary photometry yields the following AB magnitudes and upper limits:
g' > 25.3
r' = 23.8 +- 0.1
i' = 23.6 +- 0.2
z' = 23.5 +- 0.2
calibrated against the GROND zeropoints and 2MASS field stars. After
correcting for the foreground reddening of E(B-V)=0.07 (Schlegel et al.
1998) and assuming no intrinsic extinction, a fit with Hyper-z
(Bolzonella et al. 2000) results in a preliminary photometric redshift
of z = 4.0+0.3-0.5.