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GRB 101008A

GCN Circular 11318

Subject
GRB 101008A: Swift detection of a burst
Date
2010-10-08T16:52:27Z (15 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU),
S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD),
J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), 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), M. C. Stroh (PSU) and E. Troja (NASA/GSFC/ORAU)
report on behalf of the Swift Team:

At 16:43:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 101008A (trigger=435903).  Swift could not slew to the
burst location due to an Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 328.891, +37.062 which is 
   RA(J2000) = 21h 55m 34s
   Dec(J2000) = +37d 03' 44"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows many peaks
in an overall FRED envelope structure with a duration of about 15 sec. 
The peak count rate was ~2500 counts/sec (15-350 keV), at ~1 sec 
after the trigger. 

Due to an observing constraint, Swift will not slew until 
T0+50.8 minutes. There will be no XRT or UVOT data until
this time. 

Burst Advocate for this burst is W. H. Baumgartner (wayne AT milkyway.gsfc.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 11319

Subject
GRB 101008A: Swift/XRT Detection of an Afterglow with no UVOT Counterpart
Date
2010-10-08T18:34:31Z (15 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <Stephen.T.Holland@nasa.gov>
W. H. Baumgartner (GSFC/UMBC),
P. A. Evans (U Leicester),
S. T. Holland (CRESST/GSFC/USRA),
N. P. M. Kuin (UCL-MSSL),
C. Pagani (U Leicester),
K. L. Page (U Leicester), and
M. H. Siegel (PSU)
report on the behalf of the Swift UVOT team:

    The XRT began observing the field of GRB 101008A (Baumgartner et al. 2010,
GCNC 11318) at 17:35:56.9 UT, 3161.7 seconds after the BAT trigger.  Using promptly
downlinked data we find an uncatalogued X-ray source located at RA, Dec 328.87463,
37.06580 which is equivalent to:

    RA(J2000) =  21h 55m 29.91s
   Dec(J2000) = +37d 03' 56.9"

with an uncertainty of 3.9 arcseconds (radius, 90% containment).  This
location is 48 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.  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 in excess of the Galactic value (1.44 x
10^21 cm^-2, Kalberla et al. 2005), with an excess column of 3
(+4.38/-2.94) x 10^21 cm^-2 (90% confidence).

    UVOT took a finding chart exposure of 150 seconds with the white filter
starting 3167 seconds after the BAT trigger.  No credible afterglow candidate
has been found in the initial data products.  The 2.7' x 2.7' sub-image covers
100% of the XRT error circle.  The preliminary 3-sigma upper limit in the white
filter is 20.3 mag.  No correction has been made for the expected Galactic
extinction corresponding to a reddening of E_{B-V} =  0.19 mag.  Photometry is
on the UVOT photometry system of Poole et al. (2008).

GCN Circular 11320

Subject
GRB 101008A: 1.23m CAHA optical observations
Date
2010-10-08T20:59:00Z (15 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (IAA-CSIC,  Granada),  U. Carsenty  (DLR,  Berlin), P.  
Kubanek  (IAA-CSIC, Granada  &  U. of Valencia), G. Hahn  (DLR,  
Berlin), report on behalf of a larger collaboration:

"We have carried out R-band observations of the Swift GRB 101008A  
(Baumgartner et al., GCNC 11318, GCNC 11319) with the 1.23m Calar Alto  
telescope. The observations were carried out in R-band on October  
8.7957-8.8118 UT (2.38 -  2.76 hours post  trigger) under poor  
atmospheric conditions. We do not detect any optical source consistent  
with the XRT error circle (Baumgartner et al., GCNC 11319) down to a  
limiting magnitude of R=19.7 (3 sigma, calibrated against USNO-B1.0)".

GCN Circular 11321

Subject
GRB 101008A: Enhanced Swift-XRT position
Date
2010-10-08T21:32:43Z (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 1745 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 101008A, 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 = 328.87505, +37.06713 which is equivalent
to:

RA (J2000): 21h 55m 30.01s
Dec (J2000): +37d 04' 01.7"

with an uncertainty of 2.0 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 11324

Subject
GRB 101008A: SAO RAS optical observations
Date
2010-10-09T01:56:35Z (15 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
A. S. Moskvitin, T. A. Fatkhullin, A. V. Zyazeva
report on behalf of a larger collaboration:

We have observed the field of the GRB 101008A (Baumgartner et al.,
GCN#11318, GCN#11319; Beardmore et al., GCN#11321) with the 1m
telescope Zeiss-1000 of SAO RAS, Russia. The observations were carried
out in Rc band on October, 8.763 -- 8.800 UT (1.581 -- 2.484 hours
after the trigger).

We have detected three possible candidates of the OT near the enhanced
XRT error box, which are absent in the DSS R-band image.
A comparison of the DSS and our images is demonstrated at
ftp://ftp.sao.ru/pub/grb/GRB101008A/GRB101008A.jpeg

We have measured the R magnitudes of these three objects according
to R2 = 16.33 of the USNO-B1.0 star 1270-0570798:

S1 R = 20.84 +/- 0.04
S2 R = 21.03 +/- 0.06
S3 R = 21.01 +/- 0.05

All the errors are formal and they do not include the errors of
the USNO-B1.0 to Johnson-Cousins photometric system transformation.

This message may be cited.

GCN Circular 11325

Subject
GRB 101008A: Swift-XRT refined analysis
Date
2010-10-09T08:36:00Z (15 years ago)
From
Claudio Pagani at U of Leicester <cp232@star.le.ac.uk>
C. Pagani (U. Leicester) and W. H. Baumgartner (GSFC/UMBC) report on
behalf of the Swift-XRT team:

We have analysed 5.5 ks of XRT data for GRB 101008A (Baumgartner et al.
GCN Circ. 11318), from 3169 s to 26.9 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Beardmore et al. (GCN. Circ 11321).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.2 (+0.5, -0.3).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+/-0.5). The best-fitting
absorption column is 2.8 (+2.0, -1.4) x 10^21 cm^-2, in excess of the
Galactic value of 1.4 x 10^21 cm^-2 (Kalberla et al. 2005). The counts
to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from
this spectrum is 4.5 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
1.2, the count rate at T+24 hours will be 1.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x
10^-14 (8.9 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00435903.

This circular is an official product of the Swift-XRT team.

GCN Circular 11326

Subject
GRB101008A, GROND detection of a fading afterglow
Date
2010-10-09T10:58:06Z (15 years ago)
From
Marco Nardini at MPE <nardini@mpe.mpg.de>
M. Nardini, P. Schady, J. Greiner (MPE Garching) report on behalf of the
GROND team:

We observed the field of GRB 101008A (Swift trigger 435903; Baumgartner et
al., GCN#11318) 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 00:26 UT 2010 October 9th, 7.8h time after the GRB
trigger, and lasted 2 hours. They were performed at an average seeing of
1.2  and at an average airmass of 2.5.

In all our g'r'i'z'JHK images we detect the 3 objects reported by
Moskvitin et al., GCN#11324.

While sources S1 and S3 do not show any clear fading with respect to that
reported by  Moskvitin et al., GCN#11324, our  preliminary  photometry
shows  that S2 has faded with respect to the value reported by Moskvitin
et al. (GCN#11324). Calibrating our images against the same USNO star as
Moskvitin et al., we calculate a fading of ~0.7mag between the GROND
preliminary photometry centred at 8.7h after the trigger and that reported
in Moskvitin et al.

We therefore conclude that this is the optical/NIR afterglow of GRB101008A.

Our photometry is not corrected for foreground extinction of E(B-V)=0.19.
The detection in g' band implies a redshift constraint z<3.5.

GCN Circular 11327

Subject
GRB 101008A: Swift-BAT refined analysis
Date
2010-10-10T02:30:51Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-248 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 101008A (trigger #435903)
(Baumgartner, et al., GCN Circ. 11318).  The BAT ground-calculated position is
RA, Dec = 328.882, 37.060 deg which is 
   RA(J2000)  =  21h 55m 31.8s 
   Dec(J2000) = +37d 03' 36.4" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 58%.
 
The mask-weighted light curve shows a single FRED-like peak starting ~T-30 sec,
peaking at ~T+0 sec, and returning to background at ~T+100 sec.
T90 (15-350 keV) is 104 +- 35 sec (estimated error including systematics).
 
The time-averaged spectrum from T-4.0 to T+106.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.59 +- 0.24.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.42 sec in the 15-150 keV band
is 1.6 +- 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/435903/BA/

GCN Circular 11328

Subject
GRB 101008A: MASTER prompt optical observations
Date
2010-10-10T18:46:51Z (15 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov
Ural State University, Kourovka

K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres,
S.Yazev, N.M.Budnev,
Irkutsk State University


E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov,
D.Zimnukhov, M. Kornilov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory


V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina
Blagoveschensk Educational State University, Blagoveschensk



MASTER-Net robotic telescopes (MASTER-Net: http://observ.pereplet.ru)
located  near Ekaterinburg (Kourovka)  and Tunka (Baykal Lake) was pointed 
to the Swift GRB 101008A (Baumgartner et al., GCN#11318, GCN#11319; 
Beardmore et al., GCN#11321) 53 s after trigger time (immediately after 
roof opening and with last night focus) and 8309s after trigger time (the 
Tunka delay was due to weather conditions).

Time duration of the  GRB 101008A is 104 +- 35 sec (Barthelmy et al., 
GCN#11327). So we have prompt optical limit at Kourovka site.
We see marginaly possible OT (S2,  Moskvitin et al.,GCN#11324; Nardini et 
al., GCN#11326) at Tunka observations.

We have next unfiltered estimation:

t_start-t_trig(s)   mean time     exp_time(s)     m             Coadd? 
Site
--------------------------------------------------------------------------
       53            58    10         >14.5        N             Kourovka
       53           141   410         >16.0        Y             Kourovka
     8309         10260   540       19.5+-1.0      Y             Tunka
--------------------------------------------------------------------------
MASTER II have 2 images per exposition time.
The message may be cited.

mailto: lipunov@sai.msu.ru

GCN Circular 11329

Subject
GRB 101008A: MASTER prompt optical observations (correction to GCN#11328)
Date
2010-10-10T18:59:43Z (15 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
I am sorry, the table in GCN#11328
  is :

t_start-t_trig(s)   mean time     exp_time(s)     m      Coadd?    Site
--------------------------------------------------------------------------
       53              58            10          >14.5     N      Kourovka
       53             141           410          >16.0     Y      Kourovka
     8309           10260           540        19.5+-1.0   Y      Tunka
--------------------------------------------------------------------------

The message may be cited.

mailto: lipunov@sai.msu.ru

GCN Circular 11330

Subject
GRB 101008A: Fermi GBM observation
Date
2010-10-11T16:29:13Z (15 years ago)
From
Lin Lin at UAH/NAOC <ll0005@uah.edu>
Lin Lin (UAH)
report on behalf of the Fermi GBM Team: 

"At 16:43:15.61 UT on 08 Oct. 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 101008A (trigger 308248997 / 101008697).

The burst was also detected by the SWIFT-BAT
(W. H. Baumgartner et al. 2010, GCN 11318)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight is 79 degrees.

The GBM light curve shows a fast rise - slow decay peak
with a duration (T90) of about 7 s (50-300 keV). 
The time-averaged spectrum from T0-1.536 s to T0+5.376 s is 
best fit by a simple power law function with index -1.42 +/- 0.03
(C-stat 1249.1 for 612 d.o.f.).

The event fluence (10-1000 keV) over the above time interval is 
(2.016 +/- 0.083)E-6 erg/cm^2. The 0.064-sec peak photon flux measured 
starting from T0+1.344 s in the 10-1000 keV band 
is 4.90 +/- 0.84 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."

GCN Circular 11352

Subject
GRB 101008A: optical observations
Date
2010-10-18T10:06:08Z (15 years ago)
From
Alina Volnova at SAI MSU <alinusss@gmail.com>
V. Rumyantsev (CrAO),  A. Pozanenko (IKI)  report on behalf of larger GRB
follow-up collaboration:

We observed  the field  of the Swift GRB 101008A (Baumgartner et al., GCN
11318) with ZTE telescope of SAI MSU observatory on Oct. 12 (UT) 18:57 -
20:42. We clearly detect objects S1 and S3 (Moskvitin  et al., GCN 11324) in
coordinates (J2000) RA=21 55 29.91, Dec=+37 03 56.6 and RA=21 55 29.85,
Dec=+37 04 05.0, correspondingly. We do not detect the object  S2
(Moskvitin  et al., GCN 11324; Nardini et al., GCN 11326). The photometry is
based on the same USNO star as Moskvitin et al.

Source,  T0+,     Filter,   Exposure,    mag.,        Upper Limit (3 sigma)
             (mid, d)              (s)

S1        4.1297    R       97x60           21.0 +/- 0.1      22.4
S2        4.1297    R       97x60           21.6 +/- 0.2      22.4

Since we do not detect the afterglow candidate S2 up to R=22.4 we can
confirm the GRB 101008A afterglow detection.
The finding chart can be found at
http://grb.rssi.ru/GRB101008A/GRB101008a_101012_ZTE.gif

GCN Circular 11353

Subject
GRB 101008A: correction to the GCN 11352
Date
2010-10-18T12:31:09Z (15 years ago)
From
Alina Volnova at SAI MSU <alinusss@gmail.com>
V. Rumyantsev (CrAO), �A. Pozanenko (IKI) �report on behalf of larger
GRB follow-up collaboration:

We do not detect the object �S2 �(Moskvitin �et al., GCN 11324;
Nardini et al., GCN 11326). And the table should be read as

Source, �T0+, � � Filter, � Exposure, � �mag., � � � �Upper Limit (3 sigma)
� � � � � � �(mid, d) � � � � � � �(s)

S1 � � � �4.1297 � �R � � � 97x60 � � � � � 21.0 +/- 0.1 � � �22.4
S3 � � � �4.1297 � �R � � � 97x60 � � � � � 21.6 +/- 0.2

We apologize for possible inconvenience

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