GRB 140108A

J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC),
M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB),
J. A. Kennea (PSU), A. Melandri (INAF-OAB), D. M. Palmer (LANL),
M. H. Siegel (PSU), E. Sonbas (NASA/GSFC/Adiyaman Univ.),
E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (MSU) report on behalf of
the Swift Team:

At 17:18:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140108A (trigger=583338).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 325.178, +58.766 which is 
   RA(J2000)  =  21h 40m 43s
   Dec(J2000) = +58d 45' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several peaks at
T+5, T+35, and T+85 sec with a total duration of about 120 sec.  
The peak count rate was ~8000 counts/sec (15-350 keV), at ~6 sec after the trigger. 

The XRT began observing the field at 17:19:51.1 UT, 68.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 325.1106, 58.7437 which is equivalent to:
   RA(J2000)  = +21h 40m 26.54s
   Dec(J2000) = +58d 44' 37.3"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 149 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. 

The initial flux in the 2.5 s image was 3.34e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 78 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 large, but uncertain extinction expected. 

Burst Advocate for this burst is J. L. Racusin (judith.racusin 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.)

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Using  promptly downlinked XRT event data for GRB 140108A, we find an
enhanced XRT position of the afterglow: RA, Dec: 325.1127, 58.7446
which is equivalent to:
   RA (J2000)  = 21 40 27.04
   Dec (J2000) = +58 44 40.7
with an uncertainty of 2.1 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/583338.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

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

E. Gorbovskoy,  V. Lipunov, D.Denisenko, V.Kornilov, D.Kuvshinov, N.Tyurina, 
P.Balanutsa,  A.Kuznetsov
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, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Kislovodsk was pointed to the  GRB140108A 22 sec after notice 
time and 39 sec after trigger time at 2014-01-08 17:19:21.913 UT in two 
polarizations. On our first (10s exposure) set we haven`t found optical 
transient  within SWIFT error-box ( Racusin et al. GCN 15699
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  ).
The 5-sigma upper limit has been about 17.0 mag.

MASTER II  robotic telescope located in Blagoveschensk was pointed to the 
GRB140108A 30 sec after notice time and 47 sec after trigger time at 
2014-01-08 17:19:29.211 UT  in two polarizations. On our first (10s 
exposure) set we haven`t found optical transient  within SWIFT error-box.
The 5-sigma upper limit has been about 16.0 mag.

The polarizations filters oriented by RA and DEC axis (0 and 90 degrees 
from RA axis) in Kislovodsk, and 45 and 135 degrees from RA axis in 
Blagoveschensk.


The OT candidate apeared in two sites (Blagoveschensk and Kislovodsk) and 
at 2014-01-08 17:19:42 at position:

(J2000) 
RA =  21 40 26.77 
Dec = +58 44 41.4
Error=+-1 arcsc sigma

The message may be cited.

J. Gorosabel (UPV/EHU-IAA/CSIC), R. Hueso (UPV/EHU), M. Fernandez (IAA/CSIC) on behalf of a larger collaboration report:

We observed the field of GRB 140108A (Racusin et al., GCN 15699
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 ) with the 1.23m CAHA telescope. An object  with I~19 is detected at 17:55 UT coincident with the optical candidate position reported by Gorbovskoy et al.  (GCN 15701
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 ). Further observations are in progress.

Jan Strobl (1,3), Martin Jelinek (2), Cyril Polasek (1), Michal Jakubec 
(1), Petr Skala (1,3) and Rene Hudec (1,3) (1. AI ASCR Ondrejov, 2. IAA 
CSIC Granada, 3. FEE CTU Prague)

We observed the field of the Swift GRB 140108A (Racusin et al., GCNC 
15699) with the 0.5m telescope D50 and 0.25m telescope BART in Ondrejov 
(Czech Republic), starting at 17:19:20 UT, i.e. 36s after the trigger.

We detect a new variable and uncatalogued object within the XRT 
coordinates

         21:40:26.813 +58:44:40.17 (J2000) +-1".

Preliminary photometry provides brightness of R~18.0 300s after the GRB 
trigger.

This message can be cited.

E. Klunko (ISTP), M. Eselevich(ISTP), A. Volnova (IKI), A. 
Pozanenko(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of the Swift GRB 140108A (Racusin et al., GCN 
15699
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 ) with AZT-33IK telescope of Sayan observatory (Mondy) starting 
Jan., 08 (UT) 17:24:55.  We obtained several images in R-filter with 
exposure of 20,60 and 180 seconds. Within the enhanced XRT circle (Evans 
et al., GCN 15700
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 ) we detected  optical afterglow (Gorbovskoy et al., 
GCN 15701
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 ;  Gorosabel  et al., 15702) The  position of the afterglow 
coincids with  previously reported (Gorbovskoy et al., GCN 15701
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 ; Strobl 
et al., 15703). At (UT) 17:32, i.e. ~13.5 min. after GRB trigger the 
R-magnitude of the afterglow is ~19.2.

  The finding chart can be found in 
http://grb.rssi.ru/GRB140108A/GRB140108A_AZT33IK_2014-01-08T_17-30-34.png

Observation is continuing.

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

Using 634 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 140108A, 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 = 325.11211, +58.74464 which is equivalent
to:

RA (J2000): 21h 40m 26.91s
Dec (J2000): +58d 44' 40.7"

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.

P. D'Avanzo (INAF-OAB), J. L. Racusin (NASA/GSFC), P. A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 140108A (Racusin  et al. GCN
Circ. 15699
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 ),  from 58 s to 41.8 ks after the  BAT trigger. The data
comprise 2.4 ks in Windowed Timing (WT) mode (the first 8 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 15705).

The light curve shows some initial flaring activity, with the flares
peaking at around 90 and 220 s after the trigger. The underlying
emission can be modelled with a series of power-law decays. The initial
decay index is alpha=2.8 (+/-0.7). At T+184 s  the decay flattens to an
alpha of 0.52 (+/-0.03) before breaking again at T+7014 s to a final
decay with index alpha=1.20 (+0.08, -0.07).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 1.69 (+0.04, -0.03). The
best-fitting absorption column is  consistent with the Galactic value
of 7.0 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a
photon index of 1.91 (+0.16, -0.15) and a best-fitting absorption
column of 9.3 (+1.3, -1.2) x 10^21 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 5.7 x 10^-11 (1.1 x 10^-10) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     9.3 (+1.3, -1.2) x 10^21 cm^-2
Galactic foreground: 7.0 x 10^21 cm^-2
Excess significance: 3.1 sigma
Photon index:	     1.91 (+0.16, -0.15)

If the light curve continues to decay with a power-law decay index of
1.20, the count rate at T+24 hours will be 0.035 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.0 x
10^-12 (3.8 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/00583338.

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

R. Ruffini, C.L. Bianco, M. Enderli, M. Kovacevic, M. Muccino, A.V.
Penacchioni, G.B. Pisani, J.A. Rueda, Y. Wang report:

The late Swift/XRT observations of GRB 140108A (1,2) evidences the
fullfillment of the IGC paradigm (3,4). A preliminary overlapping of
its X-ray (0.3-10 keV in rest-frame) luminosity with the one of GRB
090618, namely an IGC prototype (5), gives an estimate of the redshift
of z=0.6 (+/- 0.1) (see Fig. 1
<http://www.icranet.org/images/GCN/GRB140108A.pdf>).

As a consequence, a supernova associated to GRB 140108A is expected to
emerge after 16 (+/- 3) days after the trigger.

Given the spectral parameters of the prompt emission by Swift/BAT
(<http://gcn.gsfc.nasa.gov/notices_s/583338/BA/>), this redshift
estimation leads to an isotropic energy of E_iso ~ 4x10^52 erg.

Continuous monitoring and complementary observations in all possible
wavelengths are encouraged.

References:
(1) Racusin et al., GCN 15699
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(2) D'Avanzo et al., GCN 15706
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(3) Rueda & R. Ruffini, ApJLett, 758, L7 (2012)
(4) Pisani et al., A&A, 552, L5 (2013)
(5) Izzo et al., A&A, 548, L5 (2012)

A. A. Breeveld (UCL-MSSL) and J. L. Racusin (NASA/GSFC) report on behalf 
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140108A
78 s after the BAT trigger (Racusin et al., GCN Circ. 15699
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 ).
A fading source consistent with the optical position (Gorbovskoy et al. 
GCN Circ. 15701
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 , Strobl et al. GCN Circ. 15703
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 ) is detected in the 
initial UVOT exposures.

The preliminary detection and 3-sigma upper limits using the UVOT 
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for 
the finding chart (FC) and other early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white_FC            78          228          147         20.17 � 0.20
white              571         1021          189        >21.3
v                  621         1420           97        >18.9
b                  547         1345           78        >19.8
u                  291         1320          304        >20.6
w1                 670         1462           90        >20.3
m2                 646         1444           97        >19.8
w2                 596         1395           83        >20.2

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 1.00 in the direction of the 
burst (Schlegel et al. 1998).

G. Younes (USRA/NASA-MSFC) reports on behalf of the Fermi GBM Team:

At 17:18:42.99 UT on 08 January 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140108A (trigger 410894325/140108721), which was
also detected with Swift (J. L. Racusin et al., GCN 15699
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 ). The GBM on-ground
location is consistent with the Swift/XRT location of the burst
(P. Evans et al., GCN 15705
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 ). The angle to the Fermi LAT boresight is 87 degrees
from the Swift XRT position.

The GBM light curve consists of a multiple-peak structure with a duration
(T90) of about 95 s (50-300 keV). The time-averaged spectrum from
T0 to T0+105 s is adequately fit by a Comptonized function with Epeak =
240 +/- 23 keV, and an index alpha = -1.24 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is
(1.905 +/- 0.069)E-05  erg/cm^2. The 1-sec peak photon flux measured
starting from T0+85 s in the 10-1000 keV band is 10.3 +/- 0.3 ph/s/cm^2.

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

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 140108A (trigger #583338)
(Racusin, et al., GCN Circ. 15699
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 ).  The BAT ground-calculated position is
RA, Dec = 325.129, 58.749 deg, which is 
   RA(J2000)  =  21h 40m 30.9s 
   Dec(J2000) = +58d 44' 55.3" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 71%.
 
The mask-weighted light curve shows two main peaks; the first starting at
~T-25 sec, peaking at ~T+7 sec, and almost returns to background at T+20 sec.
The second peak starts at ~T+70 sec, peaks at ~T+77 sec, and ends at ~T+110 sec
with some weak emission (2-3 sigma) out to ~T+150 sec.
T90 (15-350 keV) is 97.8 +- 3.3 sec (estimated error including systematics).
 
The time-averaged spectrum from T-24.8 to T+103.3 sec (with 2.5 sec of missing
data in the middle of the 2nd peak) is best fit by a simple power-law model.
The power law index of the time-averaged spectrum is 1.60 +- 0.05.
The fluence in the 15-150 keV band is 6.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.49 sec in the 15-150 keV band
is 6.1 +- 0.3 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/583338/BA/

A. Volnova (IKI), E. Klunko (ISTP), M. Eselevich(ISTP), A.
Pozanenko(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of the Swift GRB 140108A (Racusin et al., GCN
15699
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 ) with AZT-33IK telescope of Sayan observatory (Mondy) starting
Jan., 09 (UT) 15:10:20. We obtained several images in R-filter with
exposure of 180 seconds. On the stacked image we do not detected
the optical afterglow (Gorbovskoy et al., GCN 15701
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 ; Gorosabel et al.,
15702).

The details of the photometry are the following:

UT start,      t-T0           Filter     Exp.     OT    UL
                (mid, days)               (s)                (3 sigma)
15:10:20    0.94627       R         34*180   n/d    22.0

The photometry is based on 3 USNO-B1.0 stars:

USNO-B id        RA                Dec             R2
1487-0322168   21:40:30.85   +58:43:53.1   18.18
1487-0322049   21:40:20.16   +58:43:58.3   17.96
1487-0322069   21:40:21.62   +58:45:00.6   17.29

J. R. Cummings reports on behalf of the Swift-BAT team:

There were some small gaps in the data used in the BAT refined analysis
of GRB 140108A (Cummings et. al, GCN circ # 15710).  With a complete
data set, T90 is slightly shorter, 94 +- 4 seconds, the photon index for
the simple power-law fit to the spectrum is slightly larger, 1.62 +- 0.05,
and the total fluence is slightly larger, (7.0 +- 0.2) x 10^-7 ergs/cm^2.
The energy interval is 15-150 keV and uncertainties are 90% confidence.

In the lightcurve, the second peak is a little larger than it looked
before, and is very similar to the first peak.

The updated results have been posted at:
http://gcn.gsfc.nasa.gov/notices_s/583338/BA/

My apologies; I made a typographical error in the posted update, GCN
Circ. #15717
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 .  The total fluence should be (7.0 +- 0.2) x 10^-6 ergs/cm^2.
The corrected circular text is below:

J. R. Cummings reports on behalf of the Swift-BAT team:

There were some small gaps in the data used in the BAT refined analysis
of GRB 140108A (Cummings et. al, GCN circ # 15710).  With a complete
data set, T90 is slightly shorter, 94 +- 4 seconds, the photon index for
the simple power-law fit to the spectrum is slightly larger, 1.62 +- 0.05,
and the total fluence is slightly larger, (7.0 +- 0.2) x 10^-6 ergs/cm^2.
The energy interval is 15-150 keV and uncertainties are 90% confidence.

In the lightcurve, the second peak is a little larger than it looked
before, and is very similar to the first peak.

The updated results have been posted at:
http://gcn.gsfc.nasa.gov/notices_s/583338/BA/

T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto (Saitama U.),
M. Yamauchi, N. Ohmori, M. Akiyama, R. Kinoshita (Univ. of Miyazaki),
M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.),
K. Yamaoka (Nagoya U.),  S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun,
T. Takahashi (ISAS/JAXA), W. Iwakiri(RIKEN), Y. Hanabata (ICRR),
Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo)
on behalf of the Suzaku WAM team, report:


The long GRB 140108A (Swift/BAT trigger #583338; Racusin et al., GCN 15699
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 )
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 17:18:48.879 UT (=T0).

The observed light curve shows a multi-peaked structure starting at T0-11 s,
ending at T0+104 s with a duration (T90) of about 90 seconds.
The fluence in 100 - 1000 keV was 1.19 (+0.12/-0.50) x 10^-5 erg/cm^2.	
The 1-s peak flux measured from T0+79 s was 4.70 (+0.14/-1.81) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-11 s to T0+104 s is well fitted by a power-law with exponential cutoff model:
dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha       0.70 (+0.68/-0.85), and
Epeak       427 (+137/-72) keV (chi^2/d.o.f. = 5.8/10).

All the quoted errors are at statistical 90% confidence level.


The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html

J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program
at the Konkoly Observatory.

Starting on the evening of 08/01/2014 we observed the field of GRB 140108A
(Racusin et al., GCN 15699
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 ) 8802 sec. after the burst, using a 60/90/180 cm
Schmidt telescope located at the Mountain Station of the Konkoly
Observatory, equipped with an Apogee CCD camera through R filter. On the coadded
R images (total exp.time 900 sec) we marginally detected the OT at the
position indicated the finding chart provided by Pozarenko, GCN 15704
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 .
Based on the nearby UCAC-4 stars we provide 22.6 +/- 0.3 magnitude in the R
band for the OT. 

time from GRB.    exp    filter     Mag.      

  8802 s.         900 s     R       22.6 +/-0.3

A.Volnova (IKI), E. Klunko (ISTP), M. Eselevich(ISTP), A. Pozanenko(IKI) 
report on behalf of larger GRB follow-up collaboration:

We analyzed observations of AZT-33IK telescope of Sayan observatory, 
Mondy (Klunko et al., GCN 15704
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 ; Volnova et al., GCN 15713
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 ) of the 
Swift GRB 140108A (Racusin et al., GCN 15699
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 ).  Using bright time 
interval of the afterglow we calculated coordinates of the OT:

RA(J2000)=   21:40:26.75
RA(J2000)=  +58:44:41.3
with uncertainty of 0.4 arcsec of each coordinate.

The OT coordinates are within the enhanced XRT position (Osborne et al., 
GCN 15705
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 ) and compatible with positions reported early (Gorbovskoy et 
al., GCN 15701
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 ; Strobl et al., 15703).

The light curve of the afterglow can be found in 
http://grb.rssi.ru/GRB140108A/GRB140108A_lc_preliminary.png.

The photometry is based on USNO-B1.0 stars:
s1	1487-0322168	21:40:30.85	+58:43:53.1	18.18
s2	1487-0322049	21:40:20.16	+58:43:58.3	17.96
s3	1487-0322069	21:40:21.62	+58:45:00.6	17.29
s4	1487-0322305	21:40:41.61	+58:45:28.0	15.73

Maximum of afterglow brightness of R=18.50 +/- 0.08 was detected at 
0.00468 days after GRB trigger. It is also interesting a sharp drop at 
~0.85 days (confirmed by observations reported by Kelemen (GCN 15727
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 )) 
which could be related to a jet break observed in XRT light curve (see 
http://www.swift.ac.uk/xrt_live_cat/00583338/).