GRB 121011A

J. L. Racusin (NASA/GSFC), D. N. Burrows (PSU), V. D'Elia (ASDC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
B.P. Gompertz (U Leicester), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), C. Pagani (U Leicester),
K. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/PSU) and
R. L. C. Starling (U Leicester) report on behalf of the Swift Team:

At 11:15:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 121011A (trigger=535764).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 260.200, +41.137 which is 
   RA(J2000) = 17h 20m 48s
   Dec(J2000) = +41d 08' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 10 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 11:17:07.9 UT, 97.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 260.21504,
41.11179 which is equivalent to:
   RA(J2000)  = 17h 20m 51.61s
   Dec(J2000) = +41d 06' 42.4"
with an uncertainty of 4.3 arcseconds (radius, 90% containment). This
location is 99 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 consistent with the Galactic value of 2.34
x 10^20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 6.36e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 108 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	17:20:51.22 = 260.21340
  DEC(J2000) = +41:06:36.9  =  41.11024
with a 90%-confidence error radius of about 0.63 arc sec. This position is 9.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.76 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03. 

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.)

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 121011A (Racusin et al., GCNC 13845)
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 2012-10-11 11:17:00 UT, (~90 sec after the burst)
We detected the previously reported afterglow (Racusin et al., GCNC 13845)
in  all the three bands.

Photometric results of the OT are listed below. We used SDSS catalog
for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'   g'_err Rc    Rc_err Ic    Ic_err
-----------------------------------------------------------------------
0.00449    11:21:58    540.0     17.23 0.09   16.81 0.05   16.11 0.05
0.01159    11:32:11    540.0     17.36 0.10   16.65 0.04   16.10 0.04
------------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

L. P. Xin,  Y. L. Qiu,  J. Y. Wei,  J. Wang,  J. S. Deng, 
C. Wu,  X. H. Han on behalf of EAFON report:

We began to observe GRB121011A ( Racusin  et al., GCN 13845
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  ) 
with Xinglong TNT telescope at  11:17:24(UT), about 2 min after 
the burst. A series of white and R-band images were obtained. 
The OT reported by (Racusin  et al., GCN 13845
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 ; Kuroda et al. 13845 ) 
was detected in all images.  The brightness of this OT was about 
R=16.8 mag at  10 min after the burst, calibrated by USNO B1.0 R2 mag.
The brightness is consistent with the report by Kuroda et al. 13845.

This message may be cited.

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.Sankovich, 
D.Denisenko
Moscow Lomonosov State University, Sternberg Astronomical Institute,

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  GRB121011.47 10 sec s after
notice time and 51 sec after GRB time at 2012-10-11 11:16:21.301 UT in
two polarizations.
The 5-sigma upper limit  of the first (10s exposure) set  has been about
17.0 mag

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was pointed to the  GRB 121011A   65 sec s after notice 
time and 106 sec after GRB time at 2012-10-11 11:17:14 UT in two 
polarizations. On our first 
(10s exposure) set we haven't found optical transient  within SWIFT 
error box. The weather conditions were not very good.

The first individual image on which we see the OT was taken on 2012-10-11 
at 11:19:20, i.e 230 sec. after the GRB time. The maximum brightness
(calibrated to 0.8*R+0.2*B from USNO-B1.0) was 16.1.

The preliminary light curve is available here:
http://master.sai.msu.ru/static/GRB/GRB121011_pre_lc.png

We note that nothing is visible at the position of the OT on the Palomar 
DSS plates and on color-combined SDSS image, implying the host galaxy is 
fainter than 22.5 m.

The reduction of the whole data set is continuing.

This message can be cited.

B. Gendre (ASDC/OaR/INAF), C. Feruglio (IRAM), G. Stratta (OaR) report 
on behalf of a larger collaboration:

The GRB 121011A will be observed by XMM-Newton from 2012 Oct. 11 18:33 
UT, until Oct 12 at 11:30 UT. This observation is coordinated with an 
IRAM observation at the Interferometer of the Plateau de Bure.

We encourage any follow-up at all wavelengths, and specially 
spectroscopic observations to derive a redshift for this event.

This message can be cited.

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

Using 127 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 121011A, 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 = 260.21466, +41.11031 which is equivalent
to:

RA (J2000): 17h 20m 51.52s
Dec (J2000): +41d 06' 37.1"

with an uncertainty of 2.1 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.

M. Stamatikos (OSU), 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), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), G. Sato (ISAS),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 121011A (trigger #535764)
(Racusin, et al., GCN Circ. 13845
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 ).  The BAT ground-calculated position is
RA, Dec = 260.204, 41.123 deg, which is 
   RA(J2000)  =  17h 20m 49.0s 
   Dec(J2000) = +41d 07' 22.4" 
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
 
The mask-weighted light curve shows a single pulse starting at ~T-9 sec,
peaking at ~T+1 sec, and ending at ~T+110 or ~T+150 sec.
T90 (15-350 keV) is 75.6 +- 12.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-7.45 to T+80.10 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.10 +- 0.73, 
and Epeak of 101.5 +- 42.2 keV (chi squared 40.6 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.7 +- 0.7 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-0.69 sec in the 15-150 keV band is
1.2 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.20 +- 0.14 (chi squared 49.2 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/535764/BA/

D. Malesani (DARK), P. D'Avanzo (INAF/OABr), A. Melandri (INAF/OABr), V. 
Nascimbeni (Univ. Padova), C. Padilla (INAF/TNG), report on behalf of 
the CIBO collaboration:

We observed the optical afterglow of GRB 121011A (Racusin et al., GCN 
13845
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 ) with the TNG equipped with DOLoRes.

The afterglow is well detected in a single 5-min exposure, with a mean 
time Oct 11.829 UT (8.63 hr after the GRB). Its magnitude is R = 21.74 
+- 0.06, assuming R = 17.84 for the USNO star at RA = 17:20:44.70, Dec = 
+41:04:52.7.

The afterglow has the following coordinates (calibrated against USNO-B1 
stars):

RA = 17:20:51.22
Dec = +41:06:37.4

with an estimated uncertainty of 0.4".

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

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.Sankovich, 
D.Denisenko
Moscow Lomonosov State University, Sternberg Astronomical Institute,

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

I.Zalozhnich,  A. Popov, A. Bourdanov
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)

Two MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk and Tunka (Baykal lake) was pointed to the GRB 
121011A (Racusin et al., GCNC 13848) 51 sec after Trigger time at
2012-10-11 11:16:21.301 UT and 106 sec after Trigger time at
2012-10-11 11:17:14 UT in four polarizations (Yurkov et al., GCNC 13845).

Unfortunately the weather conditions were not very good at Tunka site.

We detected OT (Racusin et al., GCNC 13848; Kuroda et al. GCNC 13845;
Xin et al., GCNC 13847).

The preliminary results of the photometry calibrated to 0.8*R+0.2*B from 
USNO-B1.0:

     UTC	   Tmean-Tgrb Exp,s.    mag	s/n   magerr  filter  Site  Coadd

  11:16:21.0	56	10	>16.9	N/A	N/A	P/	Amur	No
  11:16:21.0	56	10	>16.9	N/A	N/A	P\	Amur	No
  11:16:21.0	96	80	>18.2	N/A	N/A	P/	Amur   Yes
  11:16:21.0	96	80	>18.2	N/A	N/A	P\	Amur   Yes
  11;18;29.0	200	40	>18.2	N/A	N/A	P/	Amur	No
  11;18;29.0	200	40	>18.2	N/A	N/A	P\	Amur	No
  11:19:20.429	255	50	17,38	5.9	0.18	P/	Amur	No
  11:19:20.461	255	50	17,17	5.8	0.19	P\	Amur	No
  11:20:21.37	321	60	16,89	8.9	0.12	P/	Amur	No
  11:20:21.396	321	60	16,9	8.1	0.13	P\	Amur	No
  11:21:32.001	397	70	16,77	11.1	0.10	P/	Amur	No
  11:21:32.02	397	70	16,81	11.5	0.09	P\	Amur	No
  11:22:52.945	487	90	16,59	14.7	0.07	P/	Amur	No
  11:22:52.998	487	90	16,49	15.8	0.07	P\	Amur	No
  11:24:33.654	599	110	16,42	18.7	0.06	P/	Amur	No
  11:24:33.678	599	110	16,57	16.6	0.07	P\	Amur	No
  11:26:34.121	729	130	16,55	17.6	0.06	P/	Amur	No
  11:26:34.144	729	130	16,5	18.4	0.06	P\	Amur	No
  11:28:54.944	885	160	16,69	18.1	0.06	P/	Amur	No
  11:28:54.947	885	160	16,7	15.5	0.07	P\	Amur	No
  11:31:45.672	1065	180	16,73	15.3	0.07	P/	Amur	No
  11:31:45.706	1065	180	16,72	14.2	0.08	P\	Amur	No
  11:35:11.589	1271	180	17,05	13.5	0.08	P/	Amur	No
  11:35:11.606	1271	180	17,03	11.1	0.10	P\	Amur	No
  11:38:37.563	1477	180	17,23	10.4	0.10	P/	Amur	No
  11:38:37.586	1477	180	17,25	10.3	0.11	P\	Amur	No
  11:42:12.62	1693	180	17,36	9.2	0.12	P/	Amur	No
  11:42:12.636	1693	180	17,48	7.7	0.14	P\	Amur	No
  11:45:38.297	1898	180	17,44	8.2	0.13	P/	Amur	No
  11:45:38.319	1898	180	17,44	7.2	0.15	P\	Amur	No
  11:49:03.877	2104	180	17,67	5.7	0.19	P/	Amur	No
  11:49:03.906	2104	180	17,73	5.0	0.22	P\	Amur	No
  11:52:29.982	2309	180	17,91	4.7	0.23	P/	Amur	No
  11:52:30.004	2309	180	17,82	5.4	0.20	P\	Amur	No
  11:55:55.714	2515	180	18,08	4.7	0.23	P/	Amur	No
  11:55:55.710	2515	180	18,04	3.4	0.32	P\	Amur	No



The mean (F/ - F\)/(F/ + F\) 100 < 2% during detection time.


The light curve between 200 sec and 6600 sec is very simmetrical in
log(F) - log (t) coordinates (like to bell) with parabolic low :

    m - m_max  = - A (log t/t_max)^2     (1)


A = 4.2 +/- 0.1



where t is time from GRB trigger in sec, t_max = 633+-11s, m_max = 
16.60+/-0.02 . We 
stress that this formulae does not depend on redshift.

The phenomenological formula discribed by Kocevski, D., Ryde, F., & Liang, E. 
(2003, ApJ, 596, 389) may be discussed in this situation but after z 
determination.

The preliminary light curve is available here:
http://master.sai.msu.ru/static/GRB/GRB121011_lc.gif

The preliminary approximation (formula(1)) is available here:
http://master.sai.msu.ru/static/GRB/GRB121011_lc_aproximation.png
This message can be cited.

A. Volnova (SAO MSI, IKI), A. Matkin (UAFO, ISON), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of the Swift GRB 121011A (Racusin et al., GCN 13845
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 ) with VT-50 (0.5-m) telescope of UAFO/ISON-Ussuriysk observatory starting on Oct. 11 (UT) 11:21:29, i.e. 6 minutes after burst trigger. We took several unfiltered images of 30 s exposures ending observations on (UT) 12:17:00. In initial frames we clearly detect afterglow (Racusin et al., GCN 13845
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 ). Preliminary photometry of some early images is based on USNO-B1.0 stars (R2):

T_start T0+, Filter, exposure, OT 
(UT) mid (d) (s) 

11:21:29 0.00433 none 30 16.70 +/- 0.08
11:27:04 0.00821 none 30 16.64 +/- 0.07
11:33:14 0.01249 none 30 16.80 +/- 0.10
11:38:12 0.01594 none 30 17.30 +/- 0.10

J. P. U. Fynbo (DARK), D. Xu (WIS), D. Malesani (DARK), A.
Sodor(Konkoly Observatory of Hungary, Royal Observatory of Belgium) ,
P. Jakobsson (U. Iceland) report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 121011A (Racusin et al.,
GCN13845
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 ) using the 2.5m Nordic Optical Telescope (NOT) equipped with
ALFOSC.

The afterglow is clearly detected in each of the two 300s exposures,
with a mean time Oct. 11.830 UT (i.e., 8.666 hr after the BAT
trigger). We found its magnitude R=21.76+/-0.10, calibrated with the
USNO B1 star # 1310-0279773 (R1 = 17.84; same as calibration in
Malesani et al., GCN #13853
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 ).

We also carried out 2x20 min spectroscopic observations after the
above photometry. There is a faint trace in the 2D spectrum but the
S/N in the 1D spectrum is low. Preliminary analysis of the 1D spectrum
shows very weak sign of z~0.58.

D.N. Burrows (PSU), O.M. Littlejohns (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia
(ASDC), A. Maselli  (INAF-IASFPA), J.A. Kennea (PSU), M.C. Stroh (PSU)
and J.L. Racusin report on behalf of the Swift-XRT team:

We have analysed 7.1 ks of XRT data for GRB 121011A (Racusin  et al.
GCN Circ. 13845
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 ), from 103 s to 16.8 ks after the  BAT trigger. The
data comprise 28 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN. Circ 13850).

The light curve can be modelled with  a power-law decay with a decay
index of alpha=1.50 (+/-0.04).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.71 (+0.35, -0.10). The
best-fitting absorption column is  consistent with the Galactic value
of 2.3 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 4.0 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     0 (+4.9, -0) x 10^20 cm^-2
Galactic foreground: 2.3 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.71 (+0.35, -0.10)

If the light curve continues to decay with a power-law decay index of
1.50, the count rate at T+24 hours will be 5.9 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x
10^-14 (2.5 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/00535764.

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

M. Ohno (Hiroshima U.), G. Vianello (Stanford), J. L. Racusin (NASA/GSFC) and E. Sonbas (Adiyaman Univ.), report on behalf of the Fermi-LAT team:

The Fermi Large Area Telescope (LAT) detected emission from GRB 121011A, also detected by Swift (Racusin et al. GCN 13845
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 ) and GBM (trigger 371646928/121011469) at approximately 11:15:25 UT on October 11, 2012.

The burst location was inside the LAT field of view at an angle of ~56 degrees to the LAT boresight, and had a zenith angle of 86 degrees. No significant excess is seen using standard analysis procedures.

Using the non-standard LAT Low Energy (LLE) data selection, over 100 counts above background were detected within a 20 s interval coinciding with the time of the GBM emission, with a significance of 4 sigma. This data selection has insufficient spatial resolution to provide a reliable LAT localization. This detection is due to low energy gamma-rays (below 100 MeV). Indeed, no events were observed above 100 MeV using the standard analysis classes.

A GBM circular on GRB 121011A is forthcoming.

The Fermi LAT point of contact for this burst is Eda Sonbas (edasonbas AT gmail.com).

The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.

Shaolin Xiong (UAH), David Byrne (UCD) and Charles Meegan (USRA)
report on behalf of the Fermi GBM Team:

"At 11:15:25.70 UT on 11 October 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 121011A (trigger 371646928 / 121011469),
which was also detected by the Swift/BAT (Racusin et al. 2012, GCN 13845
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 )
and Fermi/LAT (M. Ohno et al. 2012, GCN 13859
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 ).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is ~56 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve shows a single peak with long tail
with a duration (T90) of about 66 s (10-1000 keV).
The time-averaged spectrum from T0+0.0 s to T0+67.6 s is
adequately 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 1160 +/- 410 keV.

The event fluence (10-1000 keV) in this time interval is
(1.00 +/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+7.23 s in the 10-1000 keV band is 2.2 +/- 0.2 ph/s/cm^2.

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

V. Lipunov
Moscow Lomonosov State University, Sternberg Astronomical Institute,


The correct   formula (1) (Yurkov et al.,GCNC 13854) is:

"The light curve between 200 sec and 6600 sec is very simmetrical in
log(F) - log (t) coordinates (like to bell) with parabolic low :

    m - m_max  = A (log t/t_max)^2     (1)


A = 4.2 +/- 0.1

where t is time from GRB trigger in sec, t_max = 633+-11s, m_max =
16.60+/-0.02 . We
stress that this formulae does not depend on redshift."

This message can be cited.

J. P. U. Fynbo (DARK/NBI), D. Malesani (DARK/NBI), D. Xu (WIS), report 
on behalf of a larger collaboration:

We performed a careful analysis of the spectrum secured at the NOT 
(Fynbo et al., GCN 13856
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 ) of the afterglow of GRB 121011A (Racusin et 
al., GCN 13845
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 ). We confirm that a faint continuum is visible in our 
data, but we cannot detect any clear feature with confidence. The 
redshift z = 0.58 suggested in GCN 13856
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  is therefore not correct.

A sharp break is detected at the blue end of our spectrum around 4100 
AA, but its interpretation is not straightforward. If due to Ly alpha at 
z = 2.3, than we would expect surviving flux blueward of the break. If 
due to the Lyman limit at z = 3.4, than we would expect to see the Lyman 
forest redward of the break, which we do not. We thus believe this break 
to be an artifact of the data, but encourage other observers to attempt 
spectroscopy with large area telescopes, also given the detection of the 
GRB by Fermi/LAT (Ohno et al., GCN 13859
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 ).

S. T. Holland (STScI) 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 121011A 109 s after
the BAT trigger (Racusin et al., GCN Circ. 13845
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 ).  A source consistent with the
XRT position (Evans et al. GCN Circ. 13850
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 ) is detected in the initial UVOT
exposures.

The preliminary UVOT position is:
    RA  (J2000) =  17:20:51.23 = 260.21346 (deg.)
    Dec (J2000) = +41:06:37.1  = +41.11030 (deg.)
with an estimated uncertainty of 0.52 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white              109          258          147         18.96 +/- 0.06
v                 4093         5729          393         19.81 +/- 0.21
b                 3476         3676          197         19.51 +/- 0.18
u                 4708         4908          197         19.67 +/- 0.18
w1                4503        15916         1183        >20.9
m2                4298         5933          393        >22.6
w2                3888         5524          393        >21.0

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).

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


Follow-up observations of GRB 121011A (Racusin et al., GCN13845
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 ) were done
using 1.04m telescope at Nainital in good sky conditions starting at
13:17:03 (UT) on 11-10-2012. Several frames in B, V, R_c and I_c pass-bands
were obtained with exposure time of 300 sec each.

The optical afterglow candidate (Racusin et al., GCNC 13845) is clearly
detected in our frames. The preliminary photometry for the first R_c and
I_c frames were 19.59 +- 0.02 mag and 19.14 +- 0.05 mag respectively,
calibrated against nearby USNO stars. Further observations are continued.

This massage may be cited.

A.J. van der Horst (University of Amsterdam) reports on behalf
of a large collaboration:

"We observed the position of the GRB 121011A afterglow at 4.9 GHz
with the Westerbork Synthesis Radio Telescope at October 14 10.01
to 18.14 UT, i.e. 2.95 - 3.29 days after the burst (GCN 13845
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 ).
We do not detect a radio source at the position of the optical
counterpart (GCN 13853
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 ). The three-sigma rms noise in the map around
that position is 75 microJy per beam. The formal flux measurement for
a point source at the position of the optical counterpart is 44 +/- 25 
microJy.

We would like to thank the WSRT staff for scheduling and obtaining these
observations."

B. Gendre (INAF-OAR/ASDC), C. Feruglio (IRAM), G. Stratta (INAF-OAR), A. 
Antonelli (INAF-OAR/ASDC), J.L. Atteia (IRAP/OMP), S. Basa (LAM/OAMP), 
M. Bo�r (Artemis/CNRS), S. Cutini (INAF-OAR/ASDC), V. D'Elia 
(INAF-OAR/ASDC), A. Klotz (IRAP/OMP), L. Piro (INAF-IAPS),  repport:

we observed the position of GRB 121011A (Racusin et al., GCN 13845
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 ) with 
the Interferometer of the Plateau de Bure on 2012-10-11, starting at 
15:30 UT for 1.46 hours, at frequency 130 GHz. The observing conditions 
were good, with a stable atmosphere (phase rms below 35 degrees), 
Tsys~200 and water vapor about 6 mm.

No afterglow has been detected, with an upper limit of 214 micro Jy.

Given the radio non detection (van der Horst, GCN 13868
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 ) and the 
faintness of this object as seen in X-ray (Burrows et al., GCN 13857
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 ), 
no further observations are planned.

We thank the technical staff of IRAM for fast support of the trigger.

This message can be cited.

Based on observations carried out with the IRAM Plateau de Bure 
Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) 
and IGN (Spain).

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

The long GRB 121011A (Swift/BAT trigger #535764; Racusin et al., GCN 13845
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 ;
Fermi-LAT detection: Ohno et al., GCN 13777
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 ) was detected by
the Suzaku Wide-band  All-sky Monitor (WAM) which covers an energy range
of 50 keV - 5 MeV at 11:15:30.264 UT (=T0).


The observed light curve shows a single peak structure starting
at T0-10 s, ending at T0+30 s with the total duration (T90) is about 31
seconds. The fluence of main pulse in 100 - 1000 keV was
  4.70 (-0.15, +0.10) x 10^-6 erg/cm^2
The 1-s peak flux measured at T0-1.0 s was
0.41 (-0.31, +0.29) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-10 s
to T0+30 s is well fitted by by a single power-law with a photon index
of 1.61 (-0.14, +0.18) (chi^2/d.o.f = 20.4/25).


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

A. Volnova (SAI MSU, IKI), A. Matkin (UAFO, ISON), I. Molotov (KIAM), A. 
Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We report the light curve of the optical afterglow of the Swift GRB 121011A 
(Racusin et al., GCN 13845
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 ). The afterglow was observed with VT-50 (0.5-m) 
telescope of UAFO/ISON-Ussuriysk observatory starting on Oct. 11 (UT) 
11:21:29 (Volnova et al., GCN 13855
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 ). The light curve obtained from series 
of 30 s unfiltered imaging can be found at

http://grb.rssi.ru/GRB121011A/GRB121011A_lc.png

The photometry is based on several nearby USNO-B1.0 stars (R2).

A. Volnova (SAI MSU, IKI), Moskvitin (SAO RAS), V. Rumyantsev (CrAO),
A. Pozanenko (IKI)


We observed the field of the Swift GRB 121011A (Racusin et al., GCN
13845
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 ) with ZTSh telescope of CrAO on Oct. 15 between (UT) 17:36 and
18:54 under good weather condition with mean seeing of about 1.5
arcsec. We took 70 frames with exposure of 60 seconds in filter R.  In
a stacked image we do not detect any source within enhanced XRT error
circle (Evans et al., GCN 13850
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 ).

We also observed the field of this GRB with Zeiss-1000 telescope of
SAO RAS on Oct. 17 between (UT) 17:45 and 18:38 under good weather
conditions with mean seeing of about 2.4 arcsec. We took 12 frames
with exposure of 200 seconds. On a stacked image we do not detect any
source either. The photometry based on a USNO-B1 star #1310-0279773
(R1 = 17.84; same
as calibration in Fynbo et al., GCN Circ. 13856
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 ; Malesani et al., GCN
13853
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 ) is following:

T0+        Filter,  Exposure, OT,  UL (3 sigma),  Telescope
(days)               (s)

4.292      R       70x60        n/d   23.5                ZTSh
6.294      R       12x200      n/d   22.3                Zeiss-1000