GRB 101024A
GCN Circular 11370
Subject
GRB 101024A: Swift detection of a burst with an optical afterglow
Date
2010-10-24T12:03:25Z (15 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
M. De Pasquale (UCL-MSSL), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), P. T. O'Brien (U Leicester),
C. Pagani (U Leicester), C. J. Saxton (UCL-MSSL),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC) and R. L. C. Starling (U Leicester)
report on behalf of the Swift Team:
At 11:39:29.82 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 101024A (trigger=437016). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 66.475, -77.248 which is
RA(J2000) = 04h 25m 54s
Dec(J2000) = -77d 14' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The lightcurve shows 4 distinct peaks, with the
brightest peaking at T0+10s. Duration was about 23s.
The XRT began observing the field at 11:40:46.8 UT, 77.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 66.5064, -77.2648 which
is equivalent to:
RA(J2000) = 04h 26m 1.54s
Dec(J2000) = -77d 15' 53.2"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 66 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (6.52 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.2
(+1.39/-1.27) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 81 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 04:26:01.73 = 66.50719
DEC(J2000) = -77:15:55.9 = -77.26552
with a 90%-confidence error radius of about 0.64 arc sec. This position is 2.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.38 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.09.
Burst Advocate for this burst is M. De Pasquale (mdp@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.)
GCN Circular 11372
Subject
GRB 101024A: Enhanced Swift-XRT position
Date
2010-10-24T14:20:40Z (15 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 614 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 101024A, 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 = 66.50630, -77.26539 which is equivalent
to:
RA (J2000): 04h 26m 1.51s
Dec (J2000): -77d 15' 55.4"
with an uncertainty of 1.8 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, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 11373
Subject
GRB 101024A: GRAS06 optical observations
Date
2010-10-24T14:59:45Z (15 years ago)
From
Veli-Pekka Hentunen at Taurus Hill Obs,A95 <veli-pekka.hentunen@kassiopeia.net>
Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill
Observatory, Varkaus, Finland) report:
GRAS06 (Global-Rent-a-Scope, Moorook, Australia) RCOS-16 telescope
and SBIG STL-1001E CCD camera were used to detect GRB 101024A
optical afterglow. The observations were started at 2010-10-24 11:58:06 (UT)
and stopped at 2010-10-24 12:30:00 (UT). Three unfiltered observations
with 600s exposure times were made. The afterglow was detected at
following position RA 04 26 01.43 and DEC -77 15 55.9 consistent those
given by Evans P.A. et al. (GCN 11370) to within positional errors.
The following magnitudes were obtained from the observations using
NOMAD1 0127-0023968 (V = 16.94) as the comparison:
Tmid(s) + T0 Filter Exp (sec) Mag Mag err Limit
1416 unfiltered 600 19.2 0.4 21.0
2074 unfiltered 600 20.8 0.8 21.0
2730 unfiltered 600 >21.0 21.0
A jpg image of the 600sec observations is available at the following
URL: http://cutenews.kassiopeia.net/data/upimages/GRB101024A.png
GCN Circular 11374
Subject
GRB 101024A: Swift-BAT refined analysis
Date
2010-10-24T17:55:08Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (GWU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), M. De Pasquale (UCL-MSSL) N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 101024A (trigger #437016)
(De Pasquale, et al., GCN Circ. 11370). The BAT ground-calculated position is
RA, Dec = 66.465, -77.261 deg, which is
RA(J2000) = 04h 25m 51.6s
Dec(J2000) = -77d 15' 39.7"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 76%.
The mask-weighted light curve consists of 4 peats, the first starting at
~T-2 sec, peaking at ~T_zero, then the 3 remaining peaks at T+3 sec,
~T+10, and ~T+18 sec, and returning to background at ~T+30 sec.
T90 (15-350 keV) is 18.7 +- 0.5 sec (estimated error including systematics).
The time-averaged spectrum from T-0.3 to T+20.1 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.15 +- 0.31,
and Epeak of 60.0 +- 9.3 keV (chi squared 49.9 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.5 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+9.39 sec in the 15-150 keV band is
5.5 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.84 +- 0.07 (chi squared 66.9 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/437016/BA/
GCN Circular 11375
Subject
GRB101024A: Swift/UVOT
Date
2010-10-24T19:21:47Z (15 years ago)
From
Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>
M. De Pasquale (UCL-MSSL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 101024A
82 s after the BAT trigger (De Pasquale et al., GCN Circ. 11370).
An optical afterglow is detected within the refined XRT error circle
(Beardmore et al., GCN Circ. 11372) in the white filter finding chart.
The same source is detected very marginally in the sum of the following
white filter exposures. It is not found in any other filter, either
in single and in summed 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_FC 82 232 147 19.4 +/- 0.2
u_FC 294 543 246 >20.3
white 573 6068 413 22.3 +/- 0.6 (2.1 sigma)
v 624 6479 413 >20.0
b 549 5864 413 >20.6
u 294 5659 459 >20.6
w1 673 5454 216 >20.1
m2 648 5249 221 >19.7
w2 599 6274 413 >20.5
The values quoted above are not corrected for the non-negligible Galactic
extinction due to the reddening of E(B-V) = 0.09 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 11378
Subject
GRB 101024A: Fermi GBM observation
Date
2010-10-24T22:06:01Z (15 years ago)
From
Sheila McBreen at MPE <smcbreen@mpe.mpg.de>
S. McBreen (UCD/MPE)
report on behalf of the Fermi GBM Team:
"At 11:39:33.60 UT on 24 October 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 101024A (trigger 309613175/101024486)
which was also detected by the Swift-BAT
(De Pasquale et al. 2010, GCN 11370).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 142 degrees.
The GBM light curve consists of three pulses with the first
pulse starting about 5 seconds before the trigger.
The event has a duration (T90) of about 24 (+/-2) s (50-300 keV).
The time-averaged spectrum from T0-0.003 s to T0+19.456 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is 1.4 (+1.6/-0.8) and
the cutoff energy, parameterized as Epeak, is 56.25 (+5.96/-5.54) keV
(CSTAT 447 for 359 d.o.f.).
The event fluence (10-1000 keV) in this time interval is
(1.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.5 s in the 8-1000 keV band
is 8.2 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 11380
Subject
GRB 101024A: Zadko observatory - Gingin. Optical observations
Date
2010-10-25T09:57:20Z (15 years ago)
From
Myrtille LAAS-BOUREZ at U.Western Australia <myrtille.laas@oamp.fr>
GRB 101024A: Zadko observatory - Gingin. Optical observations
-------------------------------------------------------------
M. Laas-Bourez (UWA/ICRAR), A. Klotz (CESR-UPS-CNRS), D. Coward (UWA), D. Blair (UWA),
M. Boer (OHP-CNRS), P. Thierry (CESR-UPS-CNRS) report:
We imaged the field of GRB 101024A detected by SWIFT
(trigger 437016) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.
The observations started 215s after the GRB trigger
(199s after the notice). The elevation of the field increased from
27 degrees above horizon and weather conditions
were good with humidity (77%).
We detect a new fading source in the error box given by SWIFT
We detected the candidate couterpart mentioned by De Pasquale et al. (GCNC 11370)
at the following position (+/- 0.5 arcsec):
RA(J2000.0) = 04h26m01s76
DEC(J2000.0) = -77d15m55s64
The first image is trailed with a duration of 30.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
IT was taken between 214.7s - 244.7s after GRB.
It will be analyzed later.
Next images show the decay of the OT:
OT was R=16.75 between 259s and 289s after GRB, filter C
OT was R=17.07 between 305s and 335s after GRB, filter C
OT was R=17.15 between 349s and 379s after GRB, filter C
OT was R=17.19 between 394s and 424s after GRB, filter C
Magnitudes were estimated with the star : NOMAD1 0127-0023961
and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=290.5330 lat=-34.1439
This message may be cited.
<http://www.zt.science.uwa.edu.au/>
GCN Circular 11381
Subject
GRB 101024A: Swift XRT refined analysis
Date
2010-10-25T11:32:55Z (15 years ago)
From
Rhaana Starling at U of Leicester <rlcs1@star.le.ac.uk>
R.L.C. Starling, P.A. Evans, K.L. Page (U. Leicester) and M. De Pasquale
(UCL-MSSL) report on behalf of the Swift-XRT team:
We have analysed 11 ks of Swift XRT data for GRB 101024A (De Pasquale et
al. GCN Circ. 11370), from 62 s to 57.2 ks after the BAT trigger. The data
comprise 8 s in Windowed Timing (WT) mode (taken while Swift was slewing),
with the remainder in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Beardmore et al. (GCN. Circ 11372).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=5.0 (+5.0, -3.9). At T+77 s the decay
flattens to an alpha of -0.03 (+0.16, -0.18) before breaking again at
T+870 s to a final decay with index alpha=1.30 (+0.10, -0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.95 (+0.13, -0.10). The
best-fitting absorption column is 1.06 (+0.29, -0.13) x 10^21 cm^-2, in
excess of the Galactic value of 6.5 x 10^20 cm^-2 (Kalberla et al. 2005).
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.0 x 10^-11 (5.1 x 10^-11) erg cm^-2
count^-1.
If the light curve continues to decay with a power-law decay index of
1.30, the count rate at T+24 hours will be 6.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x 10^-13
(3.1 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00437016.
This circular is an official product of the Swift-XRT team.
GCN Circular 11382
Subject
GRB 101024A: Zadko observatory - Gingin. Optical observations refined analysis
Date
2010-10-26T08:46:02Z (15 years ago)
From
Myrtille LAAS-BOUREZ at U.Western Australia <myrtille.laas@oamp.fr>
GRB 101024A: Zadko observatory - Gingin. Optical observations refined
analysis
-------------------------------------------------------------------------------
M. Laas-Bourez (UWA/ICRAR), A. Klotz (CESR-UPS-CNRS), D. Coward (UWA),
D. Blair (UWA),
M. Boer (OHP-CNRS), P. Thierry (CESR-UPS-CNRS) report:
We analyzed carefully early images of GRB101024A
taken with the Zadko telescope, Gingin, Australia
(see Laas-Bourez et al. 2010 GCNC 11380). Images
are unfiltered. Magnitudes are converted into R
band using the star NOMAD1 0127-0023961 R=13.61
supposing (V-R)=0.6 for the optical counterpart
of the GRB. Magnitudes are not corrected for galactic
dust extinction.
-------------------------------
start end Rmag
(s) (s)
-------------------------------
215 222 16.55 +/-0.15
222 245 16.72 +/-0.15
259 289 16.86 +/-0.12
305 335 17.06 +/-0.12
349 379 17.24 +/-0.12
394 424 17.23 +/-0.12
-------------------------------
Considering a law decay in flux proportional to
t^-alpha, there is a consistent decrease with
alpha ~ 1.1 between 215 and ~ 360 seconds.
After 360 seconds, a plateau seems to be reached
lasting at least 60 seconds.
Compared to the UVOT data taken in the same range
of time (De Pasquale et al. 2010 GCNC 11375) the
optical afterglow is very red, consistent with a
redshift z>2.
This message may be cited.
<http://www.zt.science.uwa.edu.au/>
GCN Circular 11383
Subject
GRB 101024A: GROND optical/NIR observations
Date
2010-10-26T17:45:31Z (15 years ago)
From
Thomas Kruehler at MPE/MPI <kruehler@mpe.mpg.de>
T. Kruehler, F. Olivares, M. Nardini and J. Greiner (all MPE Garching)
report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m MPG/ESO
telescope at La Silla Observatory (Chile), started observations of the
field of GRB 101024A (de Pasquale et al., GCN #11370) in g'r'i'z'JHK at
07:42 UT on 2010-10-26, 43.7 h after the burst. We detect the optical
afterglow (de Pasquale et al., GCNs #11370, 11375, Hentunen et al., GCN
#11373, Laas-Bourez et al., GCNs #11380, 11382) marginally in the r' and
i' bands.
Preliminary AB magnitudes and upper limits at a midtime of 08:14 UT on
2010-10-26 in stacked images with 50 min of total integration time in each
g'r'i'z' and 40 min in JHK are:
g' > 24.1
r' = 24.5 +- 0.3
i' = 23.8 +- 0.2
z' > 23.7
J > 21.8
H > 21.3
K > 20.5
These magnitudes have been derived by calibrating the images against the
GROND zeropoints and 2MASS field stars and are not corrected for the
expected foreground reddening of E(B-V)=0.088 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 11422
Subject
Optical observation of GRB 101024A
Date
2010-11-23T01:47:10Z (15 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Chris Stockdale (Churchill, Victoria, Australia) reports to the AAVSO
International High Energy Network the following optical observation of
GRB 101024 (GCN #11370, De Pasquale et al.):
Chris Stockdale reports a detection of the optical afterglow of GRB
101024 (GCN #11370, De Pasquale et al.; #11371, De Pasquale et al.;
#11373, Hentunen et al.; #11382, Laas-Bourez et al.; #11383 Kruehler et
al.), detecting the afterglow at the same position as the Swift UVOT
position. The afterglow was observed unfiltered for 24 minutes beginning
at 12:42:07 UT on 2010 October 24. Thirteen exposures of 24 minutes
were taken for the detection; a median combination of images 2 through
13 having a midpoint time of 12:54:25 UT on 2010 October 24 yields a CR
magnitude of 19.3 with calculated S/N of 5.5; the magnitude was measured
relative to the R-band catalog magnitude of USNO-B1.0 0127-0023867
(R=15.7). Observations were made using an SBIG ST-7XME CCD camera
attached to a 280 mm Schmidt-Cassegrain. The position of the afterglow
was imaged for an additional 60 minutes subsequent to these frames, but
the source was not detected.
The AAVSO High Energy Network was made possible through grants from the
Charles Curry Foundation and NASA.