GRB 120404A
GCN Circular 13208
Subject
GRB 120404A: Swift detection of a burst with an optical counterpart
Date
2012-04-04T13:01:42Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
G. Stratta (ASDC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
S. Campana (INAF-OAB), V. D'Elia (ASDC), P. A. Evans (U Leicester),
C. Guidorzi (U Ferrara), S. T. Holland (STScI), E. A. Hoversten (PSU),
J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU),
V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC),
A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB),
P. T. O'Brien (U Leicester), C. Pagani (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
R. L. C. Starling (U Leicester), M. C. Stroh (PSU) and
B.-B. Zhang (PSU) report on behalf of the Swift Team:
At 12:51:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120404A (trigger=519380). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 235.012, +12.882 which is
RA(J2000) = 15h 40m 03s
Dec(J2000) = +12d 52' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single symmetric peak
with a duration of about 35 sec. The peak count rate
was ~1800 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 12:53:12.4 UT, 130.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 235.00884, 12.88446 which
is equivalent to:
RA(J2000) = 15h 40m 02.12s
Dec(J2000) = +12d 53' 04.1"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 14 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 3.42
x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 7.34e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 138 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 15:40:02.29 = 235.00956
DEC(J2000) = +12:53:06.3 = 12.88508
with a 90%-confidence error radius of about 0.65 arc sec. This position is 4.6
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.37 with a 1-sigma error of about 0.16. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.05.
Burst Advocate for this burst is G. Stratta (giulia.stratta AT asdc.asi.it).
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 13209
Subject
GRB 120404A: Faulkes Telescope North afterglow confirmation
Date
2012-04-04T13:13:33Z (13 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB),
J. Japelj (U. Ljubljana) on behalf of a larger collaboration report:
"The 2-m Faulkes Telescope North robotically followed up GRB 120404A
(Stratta et al., GCN Circ. 13208) at 12:55:03 UT, corresponding to 4 min
after the GRB trigger time. We clearly detect the optical afterglow
candidate by Swift-UVOT (GCN 13208) with a magnitude of 18.8 +- 0.3
in the R filter in a 10-s exposure frame, calibrated against nearby
USNOB-1 field stars.
GCN Circular 13210
Subject
GRB 120404A: MASTER early OT limit
Date
2012-04-04T13:24:31Z (13 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
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
Moscow Lomonosov State University, Sternberg Astronomical Institute,
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk 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 GRB120404A 24 sec s after
notice time and 71 sec after GRB time at 2012-04-04 12:52:13.917 UT. On
our first (10s exposure) set we haven`t found optical transient within
SWIFT error-box (Stratta et al., GCN 13208).
The GRB was at 15 degrees under horizont.
The 5-sigma upper limit has been about 15.3 mag.
The message may be cited.
The message may be cited.
GCN Circular 13211
Subject
GRB 120404A: MITSuME Akeno Optical upper limits
Date
2012-04-04T14:51:25Z (13 years ago)
From
Yoichi Yatsu at Tokyo Tech. <yatsu@hp.phys.titech.ac.jp>
Y. Saito, Y. Aoki, S. Song, M. Hayashi, K. Kawakami, K. Tokoyoda,
R. Usui, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of
the MITSuME collaboration:
We observed GRB 120404A (Stratta et al., GCN Circular 13208) with the
optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME
50 cm telescope of Akeno Observatory, Yamanashi, Japan.
We started the observation 84 sec after the BAT trigger
from 2012-04-04 12:52:24.8 UT. And we did not find any new point source
within the XRT error circle in the three bands.
The results of photometry (3sigma upper limits) are listed below.
The photon flux were calibrated against GSC2.3 catalog.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
----------------------------------------------------------------------------------------------------
219 12:54:40 270 > 15.4 > 16.1 > 16.7
----------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]
GCN Circular 13213
Subject
GRB 120404A: Gemini-N Redshift
Date
2012-04-04T15:17:07Z (13 years ago)
From
Antonino Cucchiara at UCSC/UCO Lick <acucchia@ucolick.org>
A. Cucchiara (UCSC/UCO Lick), on behalf of a larger
collaboration reports:
On April 4.58 UT (~60 minutes after the BAT trigger)
we observed the field of GRB 120404A (Stratta et al.,
GCN 13208) using GMOS Spectrograph on the Gemini-North
8-m telescope.
The optical afterglow is clearly detected in our r-band
acquisition image.
We performed 2x900s spectroscopic observations of the
optical afterglow using the B600 grating centered at 6500
Angstrom (covering the range 5100-7900 A).
The spectrum reveals several absorption features, including
FeII2586,2600, MgII2796,2803 at a common redshift of 1.633.
Other features indicate at least one MgII intervening system at
z=1.101
We therefore suggest that the redshift of GRB 120404A is z=1.633.
We thank the Gemini-North staff for their prompt support.
GCN Circular 13217
Subject
GRB 120404A: Gemini-N Redshift correction
Date
2012-04-04T18:38:17Z (13 years ago)
From
Antonino Cucchiara at UCSC/UCO Lick <acucchia@ucolick.org>
A. Cucchiara (UCSC/UCO Lick), N.R. Tanvir (U. of Leicester) report
on behalf of a larger collaboration:
We re-analyzed the GMOS spectra of GRB 120404A presented
in GCN 13213.
Based on further analysis we report a corrected redshift
for the GRB of z=2.876.
This new value is based on the identification of SiIV1393,1403,
CIV1550,AlIII1855,1963, CII1335, CII*1335, SiII1527, SiII*1533,
SiII1808.
We note that the CIV1448 line at this redshift is partly covered
by the GMOS chip gap.
At least four different intervening systems are identified at
the following redshifts:
z1=2.551 (based on CIV1548,1550 doublet)
z2=1.776 (based on MgII2796,2803 doublet)
z3=1.633 (based on MgII2796,2803 doublet)
z4=1.101 (based on MgII2796,2803 doublet)
We encourage further spectroscopic observations and apologize for
any inconvenience the previous redshift determination may have caused.
GCN Circular 13218
Subject
GRB 120404A: Enhanced Swift-XRT position
Date
2012-04-04T20:47:59Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 852 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 120404A, 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 = 235.00951, +12.88471 which is equivalent
to:
RA (J2000): 15h 40m 2.28s
Dec (J2000): +12d 53' 04.9"
with an uncertainty of 1.6 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.
GCN Circular 13220
Subject
GRB 120404A: Swift-BAT refined analysis
Date
2012-04-05T00:40:32Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (MSU), 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),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU),
G. Stratta (ASDC), J. Tueller (GSFC)
(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 120404A (trigger #519380)
(Strata, et al., GCN Circ. 13208). The BAT ground-calculated position is
RA, Dec = 235.002, 12.883 deg, which is
RA(J2000) = 15h 40m 00.4s
Dec(J2000) = +12d 52' 57.3"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.
The mask-weighted light curve shows several overlapping peaks starting
at ~T-20 sec, peaking at ~T+4 sec, and ending at ~T+80 sec.
T90 (15-350 keV) is 38.7 +- 4.1 sec (estimated error including systematics).
The time-averaged spectrum from T-7.31 to T+38.45 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.85 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.29 sec in the 15-150 keV band
is 1.2 +- 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/519380/BA/
GCN Circular 13221
Subject
GRB 120404A : TNT optical observation
Date
2012-04-05T00:44:27Z (13 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng,
C. Wu, X. H. Han on behalf of EAFON report:
We began to observe GRB 120404A (Stratta et al., GCN Circ. 13208)
with Xinglong TNT telescope in R-band at 19:33:05(UT), 6.7 hours after
the burst. The optical counterpart (Stratta et al., GCN Circ. 13208, Guidorzi et al. GCN Circ. 13209)
was marginal detected with a brightness of 20.3 +/- 0.2 mag
calibrated to USNO B1.0 R2 mag, at the mean time of 7.4 hours after the burst.
Combined with the report by Guidorzi et al. ( GCN Circ. 13209 ), the brightness of this burst
decayed by 1.5 magnitude in R-band during 4 min and 7.4 hour after the burst,
corresponding to a shallow decay index of about 0.3 during this phase.
Further observations are encouraged.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org:8080/grb/index.html
We thank Liang Ma for performing these observations.
GCN Circular 13222
Subject
GRB 120404A: Swift-XRT refined Analysis
Date
2012-04-05T01:02:05Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), V. Mangano
(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),
M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester) and G. Stratta report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 120404A (Stratta et al.
GCN Circ. 13208), from 119 s to 23.3 ks after the BAT trigger. The
data comprise 109 s in Windowed Timing (WT) mode (the first 9 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 13218).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.15 (+0.18, -0.17). At T+544 s the decay
flattens to an alpha of 0.1 (+0.4, -0.6) before breaking again at
T+2930 s to a final decay with index alpha=1.83 (+0.21, -0.19).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.72 (+0.14, -0.13). The
best-fitting absorption column is 2.3 (+4.7, -2.3) x 10^21 cm^-2, at a
redshift of 2.87, in addition to the Galactic value of 3.4 x 10^20
cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index
of 1.90 (+/-0.12) and a best-fitting absorption column of 4.5 (+4.3,
-4.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.3
x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 3.4 x 10^20 cm^-2
Intrinsic column: 4.5 (+4.3, -4.0) x 10^21 cm^-2 at z=2.87
Photon index: 1.90 (+/-0.12)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00519380.
This circular is an official product of the Swift-XRT team.
GCN Circular 13224
Subject
GRB 120404A: MITSuME Okayama Optical Observation
Date
2012-04-05T09:17:14Z (13 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
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 120404A (Stratta et al., GCNC 13208)
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 2012-04-04 17:41:39 UT (~4.8 h after the
burst). We detected the previously reported afterglow (Guidorzi et al.,
GCNC 13209) in Rc and Ic bands.
Photometric results of the OT are listed below. We used SDSS catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Rc_err Ic Ic_err
----------------------------------------------------------------------
0.24381 18:42:07 5760.0 >20.4 20.2 0.3 19.1 0.2
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13225
Subject
GRB 120404A: MITSuME Ishigakijima Optical Observation
Date
2012-04-05T09:17:32Z (13 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (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 120404A (Stratta et al., GCNC 13208)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2012-04-04 14:31:32 UT (~1.7 h after the
burst). We detected the previously reported afterglow (Guidorzi et al.,
GCNC 13209) in only Ic band.
Photometric results of the OT are listed below. We used SDSS catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Ic Ic_err
----------------------------------------------------------------------
0.09215 15:03:44 1080.0 >18.6 >18.7 17.5 0.2
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13226
Subject
GRB 120404A: Swift/UVOT Detection
Date
2012-04-05T11:44:46Z (13 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. A. Breeveld (MSSL-UCL) and G. Stratta (ASDC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120404A
139 s after the BAT trigger (Stratta et al., GCN Circ. 13208).
A source at the UVOT position given in Stratta et al., GCN Circ. 13208,
and consistent with the enhanced XRT position (Osborne et al., GCN Circ.
13218), is detected in the initial UVOT exposures. The source is only
seen in the optical filters and rises initially and then fades. The fact
that the source is not detected in the UV filters is consistent with the
redshift of z=2.876 reported by Cucchiara et al., GCN Circ. 13217.
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 139 288 147 19.43 � 0.12
v 4734 4934 197 17.69 � 0.10
b 606 1178 58 19.22 � 0.28
u 351 1327 304 19.90 � 0.19
w1 729 6779 452 >20.3
m2 704 6574 432 >21.5
w2 656 11408 1179 >22.1
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.05 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 13227
Subject
GRB 120404A: VLT/X-shooter redshift confirmation
Date
2012-04-05T14:05:02Z (13 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D'Elia (INAF-OAR and ASI-ASDC), Paolo Goldoni (APC/U. Paris 7 and SAp/CEA), Daniele Malesani (DARK/NBI), Nial R. Tanvir (U. of Leicester), Johan P. U. Fynbo (DARK/NBI) and Andrea Melandri (INAF-OAB) and report on behalf of a larger collaboration:
We observed the optical/NIR afterglow of the Swift GRB 120404A (Stratta et al., GCN 13208; Guidorzi et al., GCN 13209) with the VLT/UT2 equipped with the X-shooter spectrograph. Observations started around 04:30 UT on 2012-04-05, which is roughly 16 hr after the trigger.
In the acquisition frame (taken 15.9 hr after the GRB), the afterglow is detected at low S/N. Comparison with two closeby SDSS stars yields R ~ 21.3 (Vega), with a systematic uncertainty of ~0.3 mag.
Four exposures in a nodding pattern with an integration time of 2400 s each were obtained in poor sky conditions. The spectrum covers an approximate wavelength range between 3000 and 25000 AA. The slit width was set to 1" in the ultra-violet/blue arm, and 0.9" in the visual and near-infrared arms, resulting in a resolving power range of approximately 4500-7500.
Preliminary reduction of the spectrum shows a weak continuum with a trough at ~4720 AA, which we identify as Ly-alpha. We also detect faint absorption lines of OI 1302 and SiIV 1393/1402 at a common redshift of ~2.88. This confirms the redshift determination by Gemini-N (Cucchiara et al., GCN 13217). A second dip matching Lya at z=2.55 is also marginally detected. This is consistent with the CIV intervening absorber reported in Cucchiara et al., GCN 13217.
We are grateful for the excellent support from the Paranal Observatory staff, in particular Claudio Melo. We are in debt to Cristiano Guidorzi for providing us a FTN finding chart.
GCN Circular 13228
Subject
GRB120404A: MOA optical observations of the initial rise afterglow
Date
2012-04-05T15:09:11Z (13 years ago)
From
Akihiko Fukui at Nagoya U/MOA <afukui@stelab.nagoya-u.ac.jp>
P. J. Tristram (MJUO), A. Fukui (NAOJ/OAO) and T. Sako (Nagoya U.)
report on behalf of the MOA collaboration.
We began prompt observations for the afterglow of GRB120404A (Stratta et al., GCN 13208)
at Apr. 4 12:55:44 UT (4.7 min after the Swift trigger 519380),
using the 61-cm B&C telescope at Mt John University Observatory in New Zealand.
We obtained a series of I and V band images with 60 sec exposure times, followed by some
120 and 180 sec exposures, until 18:04 UT (5.2 hours after the trigger).
In the first images, we detected marginal objects having I ~ 18.6 and V ~ 19.0
at the reported coordinate of the afterglow (Osborne et al., GCN13218).
The afterglow was then getting bright, as reported by Breeveld et al. (GCN 13226),
reaching I = 16.6 and V = 17.4 at around 13:40 UT (about 50 min after the trigger).
After the peak, the afterglow had faded out with the rate of +0.7 mag/hour.
The characteristic magnitudes are summarized as bellow.
UT I V
-------------------------------------------------------
12:56 18.6 +2/-0.6 19.0 +1.2/-0.6
13:40 16.6 +/- 0.1 17.4 +/- 0.1
16.50 18.4 +0.6/-0.4 19.5 +0.6/-0.4
-------------------------------------------------------
All the above magnitudes are measured on 60-sec exposure images,
and calibrated by the GSC2.3 star catalog.
The errors represent 1-sigma statistic uncertainties.
We would like to thank Alberto J Castro-Tirado for giving us useful suggestions.
We acknowledge University of Canterbury for allowing the use of the B&C telescope.
GCN Circular 13229
Subject
GRB120404A: GROND observations show steeply decaying afterglow
Date
2012-04-05T15:30:10Z (13 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
V. Sudilovsky, A. Rau , J. Greiner (all MPE Garching), report on behalf
of the GROND team:
We observed the field of GRB120404A (Swift trigger 519380; Stratta et
al., GCN #13208) simultaneously in g'r'i'z'JHK with GROND (Greiner et
al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La
Silla Observatory (Chile). Observations started at 2012-04-05 07:01:16
UT, 18.2 hours after the GRB trigger.
The afterglow (e.g., Stratta et al., GCN #13208; Guidorzi et al., GCN
#13209) is clearly detected. At mid-time of 19.3 hours post trigger and
with an exposure of 20 min we measure the following preliminary SDSS
(g'r'i'z') and 2MASS (JHK) calibrated AB magnitudes:
g' = 23.2 � 0.3
r' = 22.6 � 0.1
i' = 22.3 � 0.1
z' = 22.0 � 0.1
J = 21.2 � 0.3
H = 20.6 � 0.3
K > 20.0
The SED, corrected for the Galactic foreground reddening of E_(B-V)=0.05
mag (Schlegel et al. 1998) is best fit by a power law with a slope of
beta~1.4 and no additional rest frame extinction.
The comparison with the MITSuME observation at 4.8 hours post-trigger
(Kuroda et al., GCN #13224) and TNT measurement at 7.4 hours
post-trigger (Xin et al., GCN #13221) suggests a significant steepening
of the afterglow decay. Assuming the decay started around ~7.4 hours
post-trigger, we estimate the decay slope to be ~2.2.
GCN Circular 13230
Subject
GRB 120404A: MASTER OT observations
Date
2012-04-06T16:00:51Z (13 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
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
Moscow Lomonosov State University, Sternberg Astronomical Institute,
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
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 GRB120404A 24 sec after
notice time and 71 sec after GRB time at 2012-04-04 12:52:13.917 UT
(Yurkov et al., GCN 13210).
The observations was made with a full moon and at high zenith distance.
We see an OT (G. Stratta et. al., GCN 13208) on 3 single and some coadd
images. First time the OT seen at coadd of six first images set with
magnitude about 16.8. After this time the object was decay below 17.5
mag for an hour. The OT have a flash to 16.9 mag in our unfiltered band
(0.8R+0.2B) ~ 1 h after trigger time.
The detail imformation about observations in a table 1.
Table 1.
T_mid UT | T-T_grb sec.| Exptime | Coadd | Mag | err.mag
---------+-------------+---------+--------+------+--------
12:55:25 | 263 | 180 | 6 | 16.8 | 0.3
13:46:14 | 3311 | 180 | 1 | 17.2 | 0.4
13:49:40 | 3517 | 180 | 1 | 16.9 | 0.4
13:56:33 | 3930 | 180 | 1 | 17.1 | 0.4
14:10:22 | 4760 | 900 | 5 | 17.8 | 0.3
14:36:13 | 6311 | 1800 | 10 | 18.1 | 0.3
15:21:03 | 9001 | 1800 | 10 | 18.2 | 0.3
----------------------------------------------------------
The message may be cited.
GCN Circular 13231
Subject
GRB 120404A: EVLA Detection
Date
2012-04-06T20:55:35Z (13 years ago)
From
Ashley Zauderer at CfA <bevinashley@gmail.com>
Ashley Zauderer, Tanmoy Laskar and Edo Berger (Harvard) report:
"We observed the position of GRB 120404A (GCN 13208) with the EVLA at 22
GHz beginning 2012 Apr 5.27 UT (0.75 d after the burst). We detect a
source at 22 GHz consistent with the Swift-XRT (GCN 13218) and the UVOT
position (GCN 13208) with a flux of 82 uJy (+/- 22 uJy). The position
of the radio source is
RA 15:40:02.28 (+/- 0.01)
DEC +12:53:06.1 (+/- 0.1)
The source was not detected at 6 GHz (3-sigma upper limit of 33 uJy)."
GCN Circular 13232
Subject
GRB 120404A: SMARTS optical/IR observations
Date
2012-04-06T21:07:50Z (13 years ago)
From
Bethany Cobb at GWU <bcobb@gwu.edu>
B. E. Cobb (GWU) reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 120404A
(GCN 13208, Stratta et al.) with a mid-exposure time of 17.4 hours
post-burst (2012-04-05 06:13 UT). Total summed exposure
times amounted to 36 minutes in I and 30 minutes in J.
No source is detected at the position of the optical
afterglow (e.g. GCN 13208, Stratta et al.; GCN 13209, Guidorzi
et al.) to approximate limiting magnitudes of I > 21.6 and J > 19.6.
Magnitudes are calibrated using USNO-B1.0 stars in I, and 2MASS
stars in J.
GCN Circular 13233
Subject
GRB 120404A: JCMT SCUBA-2 sub-mm observation
Date
2012-04-06T21:32:06Z (13 years ago)
From
Ian Smith at Rice U <ian@spacsun.rice.edu>
I.A. Smith (Rice U.), R.P.J. Tilanus (JAC), N.R. Tanvir (U. of Leicester),
D.A. Frail (NRAO) report:
We observed the counterpart to GRB 120404A (Stratta et al., GCN Circ.
13208) using the SCUBA-2 sub-millimeter continuum camera on the James
Clerk Maxwell Telescope. The observation started at 13:50 UT on
2012-04-04, corresponding to 59 minutes after the burst trigger.
Exposures totaling one hour were made in marginal weather conditions.
No source was detected, with a preliminary RMS of 4.1 mJy at 850 microns.
We thank William Montgomerie for his prompt support of these observations.
GCN Circular 13234
Subject
GRB 120404A, Optical Observations
Date
2012-04-07T09:01:17Z (13 years ago)
From
Shashi Bhushan Pandey at ROTSE <shaship@umich.edu>
Brajesh Kumar, Vijay Kumar Bhatt and S.B. Pandey (ARIES, Nainital,
India, on behalf of larger Indian GRB collaboration)
We started to observe the GRB 120404A field (Swift trigger 519380, Stratta
et al., GCN Circ. 13208) with the 1.04m telescope at ARIES, Nainital
starting 2012-04-04 19:18:43 (UT). Several images in R_c and I_c pass-bands
were obtained.
The optical afterglow candidate (Stratta et al., GCN Circ. 13208,
Guidorzi et al. GCN Circ. 13209) was clearly detected in our frames.
The preliminary photometry of co-added R_c (300sec x 4) and I_c
(300sec x 3) frames yield the following magnitudes.
...............................................................
Time (MID-UT) Exp (sec) Filter Magnitude
...............................................................
19:39:40 1200 R_c 20.6 +/- 0.14
19:51:22 900 I_c 19.7 +/- 0.12
...............................................................
The nearby USNO stars have been used for calibration.
This massage may be cited.
GCN Circular 13235
Subject
GRB 120404A: optical observations
Date
2012-04-07T22:40:19Z (13 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), D. Varda (ISON), E. Sinyakov (ISON), E. Litvinenko
(UBAI), V. Kouprianov (GAO), I. Molotov (KIAM), A. Pozanenko (IKI) on behalf
of larger GRB follow up collaboration report:
We observed the field of the Swift GRB 120404A (Stratta et al., GCN 13208)
with ORI-25 (0.25-m) telescope of ISON-Blagoveschensk observatory between
Apr. 04 (UT) 13:06:10 - 14:43:45 and ORI-40 (0.4-m) telescope of ISON-Kitab
observatory between Apr. 04 (UT) 17:13:02 - 18:16:58. Several unfiltered
images were taken in both observatories. We detected optical afterglow
(Stratta et al., GCN 13208; Guidorzi et al., GCN 13209) in combined image
(see below). Coordinates of the OT are (J2000) 15:40:02.17, +12:53:06.5
with unceraininty of 0.75" on both coordinates which is compatible with
coordinates reported by UVOT team (Stratta et al., GCN 13208). A photometry
is based on nearby USNO-B1.0 stars (R2 magnitude):
t_start, t-t0 (mid), filter exp., OT, UL
(UT) d s
13:06:10 0.01529 none 12x25 n/d 16.5
13:21:11 0.03700 none 38x25 17.35 +/- 0.25 17.5
14:08:43 0.06611 none 29x25 n/d 17.9
17:13:02 0.20378 none 60x60 n/d 18.9
Based on initially non-detection of the OT we can confirm the brightening of
the afterglow (Breeveld et al., GCN 13226; Tristram et al., GCN 13228;
Gorbovskoy et al., GCN 13230) with a peak between (UT) 13:21 and 14:06
(i.e. ~ 50 min after burst trigger).
GCN Circular 13236
Subject
GRB 120404A: optical observations in Mondy observatory
Date
2012-04-08T14:58:38Z (13 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A.Volnova (SAI MSU), E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:
We observed the field of the Swift GRB 120404A (Stratta et al., GCN 13208)
with AZT-33IK telescope of Sayan observatory (Mondy). We took several images
in R-filter of 60 s exposure on Apr. 04, starting (UT) 14:31:21. We clearly
detected optical afterglow (Stratta et al., GCN 13208; Guidorzi et al., GCN
13209) in single images. A preliminary photometry of combined images is
based on nearby USNO-B1.0 stars:
t_start, t-t0 (mid), filter exp., OT, err
(UT) d s
14:31:21 0.07142 R 5x60 18.24 0.05
14:37:26 0.07564 R 5x60 18.36 0.04
14:42:30 0.07916 R 5x60 18.40 0.05
14:47:34 0.08268 R 5x60 18.36 0.07
14:52:37 0.08619 R 5x60 18.59 0.07
14:58:42 0.09041 R 5x60 18.59 0.04
15:03:46 0.09393 R 5x60 18.77 0.12
15:08:50 0.09920 R 10x60 18.76 0.06
15:19:58 0.10694 R 10x60 18.95 0.06
15:30:06 0.11432 R 10x60 18.94 0.08
15:41:14 0.12171 R 10x60 19.00 0.08
15:51:21 0.12908 R 10x60 19.30 0.09
Our photometry suggests bumpy light curve of the afterglow during our
observations.