GRB 101017A

M. H. Siegel (PSU), J. M. Gelbord (PSU), D. Grupe (PSU),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
C. B. Markwardt (NASA/GSFC), P. T. O'Brien (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 10:32:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 101017A (trigger=436429).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 291.378, -35.141 which is 
   RA(J2000) = 19h 25m 31s
   Dec(J2000) = -35d 08' 26"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a complex series
of peaks in a FRED envelope about 40 seconds long, with possible
further emission out to T+100 seconds.  The peak count rate
was ~12000 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 10:34:08.4 UT, 81.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 291.38546,
-35.14513 which is equivalent to:
   RA(J2000)  = 19h 25m 32.51s
   Dec(J2000) = -35d 08' 42.5"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 26 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 (7.69 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 4.8
(+3.15/-2.65) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 8.79e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 88 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	19:25:32.56 = 291.38565
  DEC(J2000) = -35:08:41.4  = -35.14482
with a 90%-confidence error radius of about 0.72 arc sec. This position is 2.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.98 with a 1-sigma error of about  0.19. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.17. 

Burst Advocate for this burst is M. H. Siegel (siegel AT astro.psu.edu). 
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.)

S. B. Pandey (U Mich), report on behalf of the ROTSE collaboration:

ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to
GRB 101017A (Swift trigger 436429; M. H. Siegel et al. GCN 11345
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 ),
producing images soon after the GCN notice time. We took 10 5-sec, 10
20-sec and 20 60-sec exposures. These unfiltered images are calibrated
relative to USNO A2.0 (R).

Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle or at the UVOT position, for both single
images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 15.6-16.4; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
10:34:55.2   10:35:15.2        20     16.4          127.8       N
10:37:49.3   10:42:31.6       282     17.5          301.9       Y

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. H. Siegel (PSU), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+240 sec from the recent telemetry 
downlink, we report further analysis of BAT GRB 101017A (trigger 
#436429) (Siegel, et al., GCN Circ. 11345
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 ).  The BAT ground-calculated 
position is RA, Dec = 291.377, -35.141 deg which is
    RA(J2000)  =  19h 25m 30.5s
    Dec(J2000) = -35d 08' 25.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). 
The partial coding was 43%.

The mask-weighted light curve resembles an overall FRED-like profile, 
starting at T-5 sec, peaking at T+2 sec, but with multiple shorter 
spikes superimposed.  An extended tail is detectable out to at least 
T+160 sec.  T90 (15-350 keV) is 70.0 +- 3.0 sec (estimated error 
including systematics).

The time-averaged spectrum from T-5.5 to T+111 sec is best fit by a 
simple power-law model.  The power law index of the time-averaged 
spectrum is 1.45 +- 0.03.  The fluence in the 15-150 keV band is 1.8 +- 
0.1 x 10^-5 erg/cm2.  The 1-sec peak photon flux measured from T+2.58 
sec in the 15-150 keV band is 9.4 +- 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/436429/BA/

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1922 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 101017A, 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 = 291.38586, -35.14514 which is equivalent
to:

RA (J2000): 19h 25m 32.61s
Dec (J2000): -35d 08' 42.5"

with an uncertainty of 2.6 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.

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 101017A, (Swift/BAT trigger=436429:
Siegel et.al, GCN 11345
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 ; Palmer et.al, GCN 11347
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 )
triggered Konus-Wind at T0=37961.692s UT (10:32:41.692)

The burst light curve shows a jagged FRED-like
structure with a total duration of ~45 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/GRB101017_T37961/

As observed by Konus-Wind the burst
had a fluence of (6.7 � 0.4)x10-5 erg/cm2,
and a 256-ms peak flux measured from T0+5.632s
of (7.0 � 0.9)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+40.448 s) is best fit
in the 20 keV - 2 MeV range by a power law
with exponential cutoff model, for which
alpha = -1.18 � 0.06,
and Ep = 600(-45, +52) keV (chi2 = 66/58 dof).

The spectrum at the maximum count rate
(measured from T0+0.256 to T0+7.680 s) is best fit
in the 20 keV - 2 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.9 � 0.1,
and Ep = 742(-90, +113) keV (chi2 = 62/58 dof).

All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.

D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 101017A (Siegel et al., GCN 11345
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 )
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.

The observation started on 2010-10-17 10:33:28 UT (~41 sec after
the burst). We did not find any new point source within the
enhanced XRT error circle (Goad et al., GCNC 11348) in all
the three bands.

Three sigma upper limits of the OT are listed below. We used
GSC2.3 catalog for flux calibration.


T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.01517    10:54:37  1800.0     >17.6  >17.9  >17.6
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 101017A 88s after the BAT trigger (Siegel et al.,
GCN Circ. 11345
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 ).  The source reported by Siegel et al.
is confirmed in the u and white filters but has not been detected
since the first orbit.

The 3-sigma upper limits for the finding chart (fc) and
summed exposures are reported below:

FILTER     T_start(s)  T_stop    Exposure     Mag/3uL
========================================================
white (fc)     88        238      147       19.85+-0.22
white          88       1724      409       20.09+-0.17
white        5660       7296      393         >21.03
v             630       1773      136         >18.81
v            6071      11723     1158         >19.93
b             556       1699      116         >19.66
b            5456       7091      393         >20.30
u             301        550      245       19.15+-0.23
u             301       1675      343       19.22+-0.20
u            5250       6886      393         >19.94
uvw1          679       1648      116         >19.22
uvw1         5046      13365     1112         >20.60
uvm2          654       1797      116         >19.08
uvm2         6276      12628     1082         >20.63
uvw2          605       1749      136         >19.52
uvw2         5866       7502      393         >20.22
=======================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.17 (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).

D. Grupe and M. Siegel (PSU) report on behalf of the Swift-XRT team:

We have analyzed 21.8 ks of XRT data for GRB 101017A (Siegel  et al.
GCN Circ. 11345
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 ), from 87 s to 82800 s after the  BAT trigger. The
data comprise 210 s in Windowed Timing (WT) mode with the remainder
in Photon Counting (PC) mode. The light curve can be modeled
with  a multiple broken power-law model. After an initial decay
slope of 2.22+/-0.08 the light curve steepens at T_break=260+40-20 s
with a slope of 3.85+1.13-0.34 and flattens again at T+527+52-69 s
with a decay slope of 1.35+/-0.08.

A spectrum formed from the WT mode data can be fitted with an
absorbed power-law with a photon spectral index of 1.38+/-0.06 and
an absorption column density of 20.85+2.48-2.31 x 10^20 cm^-2 which
is in excess of the Galactic column density of 7.69 x 10^20 cm^-2
(Kalberla et al. 2005). A fit to the pc mode data shows that the
spectrum has steepened with a photon spectral index of 2.08+/-0.20.
The absorption column density of this fit is consistent with the
result from the WT data. The counts to 0.3-10 keV flux conversion
factor deduced from the WT spectrum  is 6.63 x 10^-11 and
7.70 x 10^-11 erg cm^-2 count^-1 for the observed and the absorption
corrected count rates. For the pc mode we found conversion factors
are 5.00 x 10^-11 and 7.57 x 10^-11 ergs cm^-2 counts^-1,
respectively.

If the light curve continues to decay with a power-law decay index
of 1.35, the count rate at T+48 hours will be in the order of
3 x 10^-4 count s^-1, corresponding to an observed (unabsorbed)
0.3-10 keV flux of 1.5 x 10^-14 (2.3 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/00436429.

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

K. Motohara, T. Tanabe, S. Koshida, T. Morokuma,
T. Minezaki, and Y. Yoshii (University of Tokyo)
report on behalf of the TAO project team:

We observed GRB 101017A (Siegel et al., GCN 11345
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 ) with
the near-infrared camera ANIR mounted on the miniTAO 1.0m
telescope at the University of Tokyo Atacama Observatory
on the summit of Co. Chajnantor (5640 m altitude) in
the northern Chile.

The J- and Ks-band observations started from 2010-10-18
00:37 UT (14hours after the burst), and total exposure time
was 300sec for each band. No object was detected within
the enhanced XRT error circle (Goad et al., GCNC 11348).

Three sigma upper limits are listed below, where the flux
calibrations were carried out using 2MASS stars within
the FoV.

Band    Mid-UT    AB-Mag
----------------------------
Ks      00:40:25  >19.3
J       00:46:51  >19.9
----------------------------