GRB 120320A

C. B. Markwardt (NASA/GSFC), W. H. Baumgartner (GSFC/UMBC),
S. Campana (INAF-OAB), M. M. Chester (PSU), V. D'Elia (ASDC),
P. A. Evans (U Leicester), B.P. Gompertz (U Leicester),
C. Guidorzi (U Ferrara), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL),
O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
C. Pagani (U Leicester), K. L. Page (U Leicester),
J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), R. L. C. Starling (U Leicester),
C. A. Swenson (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf of
the Swift Team:

At 11:56:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120320A (trigger=518200).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.538, +8.685 which is 
   RA(J2000) = 14h 10m 09s
   Dec(J2000) = +08d 41' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed what appears to be
a series of peaks with a total duration of about 40 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 11:59:07.3 UT, 171.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 212.5177, 8.6969 which
is equivalent to:
   RA(J2000)  = 14h 10m 04.25s
   Dec(J2000) = +08d 41' 49.0"
with an uncertainty of 2.8 arcseconds (radius, 90% containment). This
location is 83 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 consistent with the Galactic value of 2.02
x 10^20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 174 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 84% 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
0.03. 

Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt 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.)

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

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


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

V.Krushinski, I.Zalozhnich,  A. Popov, A. Bourdanov, A. Punanova
Ural Federal University

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 Blagoveschensk was pointed to the  GRB120320A (Markwardt et 
al., GCN 13071
Loading...
 
 ) 32 sec s after notice time and 156 sec after GRB time
at 2012-03-20 11:58:51.633 UT. On our first (30s exposure) set we haven`t
found optical transient  within SWIFT BAT error-box (Markwardt et al., GCN 13071
Loading...
 
 ).
The 5-sigma upper limit has been about 15.4 mag .
The low limit is due to high zenit distance (8 degrees up to horizont).

The message may be cited.

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

Using 995 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 120320A, 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 = 212.51794, +8.69646 which is equivalent
to:

RA (J2000): 14h 10m 4.31s
Dec (J2000): +08d 41' 47.3"

with an uncertainty of 2.2 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.

A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester), T. Wold (JACH) and
R. Mason (Gemini) report on behalf of a larger collaboration:

We obtained observations of the field of GRB 120320A (Markwardt et al.
GCN13071
Loading...
 
 ) with both Gemini-N/GMOS in i and z, and UKIRT/WFCAM in J, H
and K. Our first observations began approximately 30 minutes after the burst,
and continued for a further 2 hours.

Within the refined X-ray error circle (Beardmore et al. GCN 13075
Loading...
 
 ) we detect a
very faint source in our GMOS imaging at position (accuracy ~0.5"):

RA(2000)=14:10:04.28
dec(2000)=08:41:47.9

The source has i~25.7+/-0.3 and z~25.3+/-0.3. It is undetected in the UKIRT
imaging to preliminary limits of J>21.6, H>20.0 and K>19.5.

This source could therefore be related to either the afterglow or the host galaxy of
GRB 120320A, but at the current time we cannot make any statements about fading.

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

Using the data set from T-240 to T+512 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120320A (trigger #518200)
(Markwardt, et al., GCN Circ. 13071
Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 212.517, 8.682 deg which is
    RA(J2000)  =  14h 10m 04.0s
    Dec(J2000) = +08d 40' 54.9"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 60%.

The mask-weighted light curve shows two overlapping weak peaks.  There is
possible low-level emission out to approximately T+90 sec.  T90
(15-350 keV) is 25.74 +- 3.55 sec (estimated error including systematics).

The time-averaged spectrum from T-0.01 to T+29.86 sec is best fit by a power
law with an exponential cutoff.  This fit gives a photon index 0.31 +- 0.95,
and Epeak of 62.8 +- 23.4 keV (chi squared 57.5 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 5.9 +- 1.6 x 10^-07 erg/cm2
and the 1-sec peak flux measured from T+24.10 sec in the 15-150 keV band is
0.5 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.58 +- 0.18 (chi squared 64.7 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/518200/BA/

[GCN OPS NOTE(20mar12):  The subject line was fixed (added the missing 0).
Appreciation goes to D.Fox for pointing out the omission.]

A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), M.C. Stroh (PSU),
D.N. Burrows (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), O.M.
Littlejohns (U. Leicester), J.P. Osborne (U. Leicester), G. Stratta
(ASDC) and C.B. Markwardt report on behalf of the Swift-XRT team:

We have analysed 7.5 ks of XRT data for GRB 120320A (Markwardt	et al.
GCN Circ. 13071
Loading...
 
 ), from 156 s to 24.3 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
13075).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=0.36 (+0.13, -0.15).

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, -0.4). The
best-fitting absorption column is  1.7 (+1.4, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 2.0 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 3.8 x 10^-11 (5.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.7 (+1.4, -1.1) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: 2.1 sigma
Photon index:	     2.0 (+0.5, -0.4)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00518200.

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

J.C. Tello (IAA-CSIC), P. Kubanek (IP AS CR & IAA-CSIC), J. Gorosabel
(IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), S. Guziy (Nikolaev St. Univ.),
Yufeng Fan, Xiaohong Zhao, Jiming Bai, Chuanjun Wang and Yuxin Xin
(Yunnan National Astronomical Observatory) and Chenzhou Cui
(Beijing National Astronomical Observatory),
report on behalf of a larger collaboration:

"We observed the field of GRB 120320A (Markwardt et al., GCNC 13071),
detected by Swift/BAT, with the 0.6m BOOTES-4/MET telescope at the Lijiang
Astronomical Observatory, China. Unfiltered images were obtained
starting 13:48:44UT at high airmass (2h12m after the burst, limited by the
local horizon). The resulting limiting magnitude (63 x 180s) is 16.3 when
calibrated with the R1Mag value of USNO-B1.0 catalogue stars."

This message may be cited.

[GCN OPS NOTE(21mar12): Per author's request CW & YX were added to the 
author list.]

Brajesh Kumar, Vijay Kumar Bhatt and S.B. Pandey (ARIES, Nainital, India,
on behalf of larger Indian GRB collaboration)

We observed the field of GRB 120320A (trigger=518200, Markwardt et al., 
GCN 13071
Loading...
 
 ) with the 1.04m telescope at ARIES Nainital starting at 
UT 18:39:42 on 20-03-2012. Three images in R_c pass-band (300 sec each)
were obtained.

The photometry of the co-added R_c frame did not reveal any new source
within the XRT error-box (Melandri et al., GCN 13079
Loading...
 
 ). The 3-sigma upper
limit of the co-added frame was found to be ~ 19.5 mag. The photometry
was done in comparison to nearby USNO- B1 stars.

This massage may be cited.

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 120320A (Markwardt et al., GCNC 13071)
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 2012-03-20 14:11:31 UT (~2.3 h after the burst)
We did not find any new point source within the enhanced XRT circle
(Beardmore et al., GCNC 13075) in all the three bands.
We also could not detect the previously reported afterglow (Levan et al.,
GCNC 13077).


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

T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.13565    15:11:36    6360.0   >20.7  >20.7  >20.0
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

M. M. Chester (PSU) and C. B. Markwardt (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 120320A
175 s after the BAT trigger (Markwardt et al., GCN Circ 13071
Loading...
 
 ).
No optical afterglow consistent with the enhanced XRT position
(Beardmore et al., GCN Circ 13075
Loading...
 
 ) or optical candidate reported
by Levan et al. (GCN Circ 13077
Loading...
 
 ) is detected in the initial UVOT
exposures.  Preliminary 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the first finding chart (FC) exposure and subsequent exposures are:

Filter    T_start(s)  T_stop(s)    Exp(s)    Mag
White_FC    175          325        147      >20.9
White       175        11021       1435      >22.1		
v           663         6181        452      >19.8		
b           589         6965        416      >20.4		
u           333         6796        678      >20.6		
uvw1        713         6591        432      >20.4		
uvm2        688         6386        432      >20.4		
uvw2        639        11148        570      >20.9

The magnitudes in the table are not corrected for the Galactic  
extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).

V. Golovnya, A. Yatsenko, L. Pakuliak (Main Astro Obs, Kyiv)
report: 
We have undertaken the review of the sky area in vicinity of 
GRB 120320A (A.P. Beardmore et al. GCN Circ.13075
Loading...
 
 ) on 
astronegatives, collected in Ukrainian NAS Main astronomical 
observatory plate archive (1976-1996). All the plates with 
the possible object appearance are digitized using Microtek 
ScanMaker 9800XL TMA and Epson Expression 10000XL flatbed 
scanners and have been placed into Golosiiv Plate Archive 
database DBGPA with open access to them.
 	The list of plates is given in the table:
YYYYMMDD/TimeUT	--Plates--	Exp.	LimMag	Star USNOA2 
19820304/012601	GUA040C000022A	22.5	16.30	0975-07400209
19820304/012601	GUA040D000023A	22.5	15.25	0975-07399206
19820513/204316	GUA040C002367	59.8	16.90	0975-07398764
19820513/204322	GUA040D002368	59.7	15.65	0975-07399102
19830510/214749	GUA040C002451	32.5	15.25	0975-07399206
19900223/015615	GUA040C001585A	20.0	15.65	0975-07399102
19900301/014633	GUA040C001620	16.0	15.65	0975-07399102
19910411/231232	GUA040C001778A	22.5	15.65	0975-07399102
19910512/205130	GUA040C001783	18.0	15.25	0975-07399206
Plates: �the plates archive identifier of DWA (D/F=400/2000, 
GUA040C, M=103"/mm) of the Ukrainian NAS Main Astro obs.
GUA040D (Marsden's number - 83) the plate number [1].
Exp.   - Duration of the maximum exposure (minutes). 
LimM   - Limited V mag, derived in the 28 minutes area around 
     the location given in A. Beardmore et al. GCN Circ.13075
Loading...
 
 : 
       RA(J2000)= 14h 10m 04.31s, Dec(J2000)= +08d 41' 47.3"
Star USNOA2 - Comparison star.
  The preview images of 9 areas together with  
the 28x28 min.of arc area from SkyMap can be found in  
http://gua.db.ukr-vo.org/img/grb/120320A/index.html
The images with full resolution are available via e-mail on 
demand.
References: 
1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0),
http://gua.db.ukr-vo.org

D. Macpherson (UWA/ICRAR), D. Coward (UWA), A. Klotz (IRAP-CNRS-OMP),
B. Gendre (ASDC/INAF-OAR), M. Todd (Curtin-ICRAR), M. Boer (UNS-CNRS-OCA),
A. Williams (PO-UWA), R. Martin (PO-UWA) report:

We imaged the field of GRB 120320A detected by SWIFT
(trigger 518200) with the UWA Zadko robotic telescope (D=100cm)
located at Gingin, Australia.

The observations started 6.8 hr after the GRB trigger.
The elevation of the field was 49 deg and humid= 63%.

9 images have been maded with a duration of 180.0s each.
At the position of the XRT afterglow (Beardmore et al., GCN 13075
Loading...
 
 ),
we do not detect any source with a limiting magnitude of
r = 20.7 on the summed images.

The nearest object, which is about 14 arcsec, in our summed image to
the XRT location, is a SDSS galaxy (J141005.65+084149.2 ) with a
photometric z = 0.34 +- 0.167.

This message may be cited.

A.Volnova (SAI MSU), �E. Sinyakov (ISON), D. Varda (ISON), I. Molotov
(KIAM), �A.
Pozanenko (IKI) on behalf of �larger GRB follow up �collaboration report:

We observed the field of the Swift GRB 120320A �(Markwardt �et al.,
GCN 13071
Loading...
 
 ) with ORI-25 (0.25-m) telescope of�ISON-Blagoveschensk
observatory. We took several unfiltered images of �60 s exposure on
Mar.20, starting (UT) 12:06:10, i.e. 10 min after trigger.

Within enhanced XRT position (Beardmore et al., �GCN 13075) we do not
detect any �source in different combined images. Photometry is based
on nearby USNO-B1.0 stars, R2-values.

UT start, � �t-t0 � � � � � filter � � �Exp. � � � �OT � � �UL (3 sigma)
� � � � � � � (mid, days) � � � � � � (s)

12:06:10 �0.00874 � �none � � 10x30 � � � n/d � � �16.7
12:06:10 �0.08435 � �none � 360x30 � � � n/d � � �19.2

A.Volnova (SAI MSU), �I. Korobtsev, E. Klunko (ISTP), A. Pozanenko
(IKI) on behalf of �larger GRB follow up collaboration report:

We observed the field of the Swift GRB 120320A �(Markwardt �et al.,
GCN 13071
Loading...
 
 ) with AZT-33IK telescope of Sayan observatory (Mondy) �on
Mar. 20 under mean seeing 2.6 arcsec. We took several images in
R-filter of �60 s exposure on Mar.20, between (UT) 14:45:13 -
15:58:25.

Within enhanced XRT position (Beardmore et al., �GCN 13075) we do not
detect any �source in a combined image. Photometry is based on nearby
USNO-B1.0 stars, R2-values.

UT start, � �t-t0 � � � � � filter � � �Exp. � � � �OT � � �UL (3 sigma)
� � � � � � � (mid, days) � � � � � � (s)

14:45:13 � 0.14275 � �R � � � 72x60 � � � � n/d � � �21.3