GRB 101213A
GCN Circular 11448
Subject
GRB 101213A: Swift detection of a burst
Date
2010-12-13T11:18:16Z (14 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori.sakamoto-1@nasa.gov>
T. Sakamoto (NASA/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB), V. D'Elia (ASDC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), N. P. M. Kuin (UCL-MSSL),
O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
C. Pagani (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), A. Rowlinson (U Leicester),
B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester), G. Stratta (ASDC) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 10:49:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 101213A (trigger=440285). Swift slewed immediately to the burst.
The BAT on-board calculated location is RA, Dec 241.286,+21.915 which is
RA(J2000) = 16h 05m09s
Dec(J2000) = +21d54'53"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a FRED-like
structure with a duration of about 100 sec. The peak count rate
was ~1700 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 10:51:08.6 UT, 105.6 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 241.3139, +21.8984 which is equivalent to:
RA(J2000) = 16h 05m 15.33s
Dec(J2000) = +21d 53' 54.2"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 110 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 114 seconds after the BAT 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 covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.06.
Burst Advocate for this burst is T. Sakamoto (Taka.Sakamoto 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 11450
Subject
GRB 101213A: Enhanced Swift-XRT position
Date
2010-12-13T14:46:49Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2148 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 101213A, 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 = 241.31370, +21.89715 which is equivalent
to:
RA (J2000): 16h 05m 15.29s
Dec (J2000): +21d 53' 49.7"
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, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 11451
Subject
GRB 101213A: Swift/UVOT Upper Limits
Date
2010-12-13T16:52:37Z (14 years ago)
From
Wayne Landsman at GSFC/SSAI <wayne.b.landsman@nasa.gov>
W. Landsman (NASA/Adnet) and T. Sakamoto (NASA/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 101213A 114 s after the BAT trigger (Sakamoto et al., GCN Circ. 11448). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 11450) is detected in the initial 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_FC 114 264 147>21.0
u_FC 327 577 246>19.8
white 114 5066 286>21.4
v 3919 4119 197>19.2
b 583 4940 216>20.5
u 327 4733 442>20.4
w1 4329 4529 197>20.3
m2 4124 4323 197>20.4
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 11452
Subject
GRB 101213A: Swift-XRT refined Analysis
Date
2010-12-13T18:29:00Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans (U. Leicester) and T. Sakamoto (NASA/UMBC) report on behalf
of the Swift-XRT team:
We have analysed 4.9 ks of XRT data for GRB 101213A (Sakamoto et al.
GCN Circ. 11448), from 95 s to 16.9 ks after the BAT trigger. The data
comprise 270 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN. Circ 11450).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.33 (+/-0.14). At T+196 s the decay
steepens to an alpha of 3.14 (+0.27, -0.18) before breaking again at
T+407 s to a final decay with index alpha=0.90 (+0.04, -0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.62 (+0.08, -0.07). The
best-fitting absorption column is 5.73 (+0.30, -0.29) x 10^21 cm^-2,
in excess of the Galactic value of 4.6 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.44 (+0.18, -0.17)
and a best-fitting absorption column of 6.5 (+0.9, -0.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.4 x 10^-11 (1.2 x 10^-10) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.5 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 4.6 x 10^20 cm^-2
Excess significance: 13.5 sigma
Photon index: 2.44 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
0.90, the count rate at T+24 hours will be 0.021 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.4 x
10^-13 (2.6 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/00440285.
This circular is an official product of the Swift-XRT team.
GCN Circular 11453
Subject
GRB 101213A, Swift-BAT refined analysis
Date
2010-12-13T21:59:32Z (14 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 101213A (trigger #440285)
(Sakamoto, et al., GCN Circ. 11448). The BAT ground-calculated position is
RA, Dec = 241.297, 21.905 deg which is
RA(J2000) = 16h 05m 11.3s
Dec(J2000) = +21d 54' 17.6"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
The mask-weighted light curve shows two overlapping peaks. The first peak is starting
at ~T-5 sec and peaking at ~T+0. The second peak is peaking at ~T+15 sec, and roughly
exponential decaying out to ~T+100 sec. T90 (15-350 keV) is 135 +- 38 sec
(estimated error including systematics).
The time-averaged spectrum from T-3.1 to T+197.1 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.53 +- 0.09. The fluence in the 15-150 keV band is 5.0 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.26 sec in the 15-150 keV band
is 2.2 +- 0.4 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/440285/BA/
GCN Circular 11454
Subject
GRB 101213A: Fermi GBM observation
Date
2010-12-14T10:01:12Z (14 years ago)
From
David Gruber at MPE <dgruber@mpe.mpg.de>
David Gruber (MPE) reports on behalf of the Fermi GBM Team:
"At 10:49:20.80 UT on 13 December 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 101213A (trigger 313930162 / 101213451)
which was also detected by the Swift/BAT
(Sakamoto et al. 2010, GCN 11448).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 129 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve conists of two overlapping FRED like pulses
with a duration (T90) of about 45 (+/-4) s (50-300 keV).
The time-averaged spectrum from T0-1.536 s to T0+44.545 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.09 (+/-0.07) and
the cutoff energy, parameterized as Epeak, is 315.0 (+46.7/-35.9) keV
(CSTAT 740 for 365 d.o.f.).
The event fluence (10-1000 keV) in this time interval is
(1.40 +/- 0.01)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.944 s in the 10-1000 keV band
is 4.67 (+/-0.32) ph/s/cm^2.
A Band function fits the spectrum equally well (CSTAT 739 for 365 d.o.f.)
with Epeak= 309.7 (+48.9/-40.0) keV, alpha = -1.1 (+/-0.07)
and beta = -2.35 (+0.29/-0.72).
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 11456
Subject
Konus-Wind observation of GRB 101213A
Date
2010-12-14T14:03:15Z (14 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long GRB 101213A (Swift/BAT trigger #440285:
Sakamoto, et al., GCN 11448; Cummings, et al., GCN 11453)
triggered Konus-Wind at T0=38958.472s UT (10:49:18.472)
The burst light curve consists of two overlapping pulses
with a total duration of ~50 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB101213_T38958/
As observed by Konus-Wind, the burst
had a fluence of (1.3 � 0.3)x10-5 erg/cm2,
and a 256-ms peak flux, measured from T0-0.512s,
of (0.60 � 0.15)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+41.216 s) is best fit
in the 20 keV - 2 MeV range by the GRB (Band) model,
for which:
the low-energy photon index alpha = -0.7 (-0.3, +0.4),
the high energy photon index beta = -2.3 (-1.5, +0.3),
the peak energy Ep = 198(-49, +92)keV, chi2 = 51/59 dof.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
GCN Circular 11457
Subject
Redshift solution(s) for GRB101213A from Swift-XRT data
Date
2010-12-15T13:55:47Z (14 years ago)
From
Sergio Campana at INAF-OAB <sergio.campana@brera.inaf.it>
S. Campana (INAF-OAB), S. Covino (INAF-OAB), A. Cucchiara (UCB/LBNL/UCSC),
P. A. Evans (U Leicester), D. Grupe (PSU), D. Malesani (DARK/NBI),
T. Sakamoto (NASA/UMBC) and R. L. C. Starling (U Leicester):
Swift BAT triggered on the early activity of GRB 101213A (Sakamoto et
al. 2010, GCN 11448). Swift XRT started observing 106 s after the
trigger observing the main event. We selected the time interval between
112-154 s during which the hardness ratio (as judged from the Swift/XRT
spectrum repository at http://www.swift.ac.uk/xrt_spectra/00440285/ )
and the power law photon index (as judged from the Swift/XRT burst analyser
http://www.swift.ac.uk/burst_analyser/00440285/ ) are consistent
with a constant. We bin the spectrum to 30 counts per energy bin and
used the latest response matrices v012. The spectrum is in Windowed Timing
mode (WT) and contains about 6,000 counts. We fit the WT spectrum with
XSPEC
using the model tbabs*ztbabs*(cutoff), (the cutoff power-law model provides
much better results in terms of column density evaluation with respect to a
simple power-law model when small spectral variations are present).
We assume a Galactic column density of 4.6x10^20 cm^-2 (Kalberla et al.
2005, A&A 440 775). In the intrinsic column density vs.
redshift plane there is just one deep minimum hinting for a redshift
z=2.9^+0.2_-0.8 (90% confidence level) and an intrinsic column density
N_H(z)=(1.5^+0.7_-0.3)x10^23 cm^-2. The X-ray spectrum is soft with
Gamma~2.5 at the end of the prompt phase and no signs of spectral curvature
(cut-off energy > 30 keV).
The absorption pattern towards GRB 101213A is complicated by the galaxy
reported by Malesani & de Ugarte Postigo (2010, GCN 11449). We tried to fit
an extra absorption component fixed either to z=0.1 or z=0.5 (i.e. the two
possible photometric redshifts of the putative host galaxy observed in the
SDSS, z=0.10+/-0.07 and z=0.47+/-0.22, respectively), with basically no
effects on the overall results. This low-redshift component is not able
alone to account for the observed absorption pattern.
Looking at the burst analyser page (see above), we also note that there is
a mismatch in the BAT and XRT power law photon indices during the short
interval during which there are contemporanous data. Motivated by this we
fit the XRT spectrum with a broken power law.
The fit is as good as the power law fit. In this case we obtain a very soft
low-energy photon index of Gamma1=3.1+/-0.2 and a high-energy photon index
Gamma2=2.0+/-0.2 (consistent with the BAT extrapolation). The transition
energy is around 3 keV. In this case, the redshift is z=0.3^+0.4_-0.1
and the
intrinsic column density is (1.1^+0.3_-0.2)x10^22 cm^-2. In this case the
redshift determination is consistent with the putative host galaxy but the
resulting X-ray spectrum is peculiar, with a spectral variation Delta
Gamma~1
and a spectrum that remains (almost) constant for ~150 s, becoming even
softer later on.
Alternatively, the X-ray spectrum could be fit (equally well) with a black
body plus a power law component. In this case the redshift is
z=0.3^+0.1_-0.2
and the intrinsic column density NH=(1.1^+0.3_-0.2)x10^22 cm^-2. The power
law is very soft with Gamma~3.3 and the black body (rest-frame) temperature
is high kT=2.3^+1.3_-0.5 keV. The black body radius is ~2x10^11 cm.
We note that the black body temperature is much higher than what is observed
in, e.g., GRB 060218 (kT~0.2 keV, Campana et al. 2006, Nat 442 1008) or
GRB 100316D (kT~0.1 keV, Starling et al. 2010, MNRAS in press).
We can conclude that in all cases, the X-ray afterglow flux is heavily
absorbed and this is in line with the non-detection with UVOT.
Given the presence of a candidate host galaxy within the XRT refined error
circle (Malesani & de Ugarte Postigo 2010), we cannot rule out a low
redshift solution, but in this case a peculiar X-ray spectrum is observed.
GCN Circular 11458
Subject
GRB 101213A : Suzaku WAM observation of the prompt emission
Date
2010-12-16T10:18:38Z (14 years ago)
From
Yoshitaka Hanabata at Hiroshima U <hanabata@hep01.hepl.hiroshima-u.ac.jp>
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
N. Ohmori, A. Daikyuji, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki),
M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA), K. Yamaoka (Aoyama Gakuin U.),
S. Sugita (Nagoya U.), Y. Terada, M. Tashiro, S. Hong, W. Iwakiri,
K. Takahara, T. Yasuda (Saitama U.), P. Tsai, Y. Urata (NCU),
N. Vasquez (Tokyo Tech.), Y. E. Nakagawa, M. Serino, T. Tamagawa (RIKEN),
K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The multi-spiked long GRB 101213A (Swift/BAT trigger #440285, GCN
11448; Sakamoto et al.,) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at
10:49:19.352 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-1s,
ending at T0+50s with a duration (T90) of about 32 seconds.
The fluence in 100 - 1000 keV was 7.47 (+1.14/-1.06) x 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+2s was 0.84 (+0.10/-0.09) photons/cm^2/s
in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+50s is well fitted by a single power-law with a photon index
of 2.08 (+0.24/-0.21) (chi^2/d.o.f = 19.9/14).
Due to the brightness of this burst, a 3% systematic error was added
for low energy channels.
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular 11544
Subject
GRB 101213A: Gemini-N galaxy redshift
Date
2011-01-07T23:49:00Z (14 years ago)
From
Ryan Chornock at Harvard <rchornock@cfa.harvard.edu>
R. Chornock and E. Berger (Harvard) report:
We obtained a 1200s spectrum of the SDSS galaxy within the XRT error
circle (Malesani & de Ugarte Postigo, GCN 11449) of GRB 101213A
(Sakamoto et al., GCN 11448; Gruber et al., GCN 11454; Golenetskii et
al., GCN 11456; Hanabata et al., GCN 11458) using GMOS on Gemini-North
on Jan. 7.65 UT to cover the spectral range 3900-8100 Angstroms. The
galaxy has a blue continuum and exhibits emission lines of H-beta and [O
III] at a redshift of z=0.414.