GRB 180316A
GCN Circular 22500
Subject
GRB 180316A: Swift detection of a burst
Date
2018-03-16T05:09:31Z (7 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Deich (PSU),
D. M. Palmer (LANL) and B. Sbarufatti (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 04:57:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180316A (trigger=814677). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 265.436, +0.737 which is
RA(J2000) = 17h 41m 45s
Dec(J2000) = +00d 44' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 20 sec. The peak count rate
was ~3000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 04:59:00.5 UT, 95.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 265.4290, 0.7497 which is equivalent to:
RA(J2000) = +17h 41m 42.96s
Dec(J2000) = +00d 44' 58.9"
with an uncertainty of 6.1 arcseconds (radius, 90% containment). This
location is 52 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.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 104 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 expected extinction corresponding to E(B-V) of
0.27.
Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.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 22501
Subject
GRB 180316A: Prompt enhanced Swift-XRT position
Date
2018-03-16T05:31:08Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 180316A, we find an
enhanced XRT position of the afterglow: RA, Dec: 265.4289, 0.7483 which
is equivalent to:
RA (J2000) = 17 41 42.94
Dec (J2000) = +00 44 54.0
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/814677.
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.
GCN Circular 22502
Subject
GRB180316A: MASTER-IAC optical detection
Date
2018-03-16T06:23:08Z (7 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, V.Kornilov, E.Gorbovskoy, P.Balanutsa,
V.Vladimirov, A.Krylov, I.Gorbunov, A.Kuznetsov, V.Chazov, D. Kuvshinov,
D.Zimnukhov
(Lomonosov Moscow State University, SAI),
R. Rebolo, M. Serra-Ricart
(The Instituto de Astrofisica de Canarias),
R.Podesta, C.Lopez, F. Podesta
(Observatorio Astronomico Felix Aguilar (OAFA),National University of San Juan,
Argentina),
H. Levato, C. Saffe
(Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San
Juan, Argentina),
D.Buckley, S. Potter
(South African Astronomical Observatory),
O.Gres, N.M.Budnev
(Irkutsk State University),
A. Tlatov, V.Senik, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory)
V.Yurkov, A.Gabovich, Yu.Sergienko
(Blagoveschensk Educational State University, Blagoveschensk),
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in IAC was pointed to the GRB180316A (Melandri et al GCN22500)
15 sec after notice time
and 44 sec after trigger time at 2018-03-16 04:58:09 UT.
There is new changing OT at SWIFT XRT (Evans et al. GCN 22501) coordinates
17 41 42.94 +00 44 54.0
The 5-sigma upper limit on the first 10s image is 17.06mag
The message may be cited.
====================================================================
The observations made on zenit distance = 42 degrees, galaxy latitude b =
15 degree.
The moon ( 2 % bright part) below the horizon (The altitude of the Moon is
-22 degree ).
The sun altitude is -30.4 degree.
The object can be observed till sunrise at 2018-03-16 07:14:55
GCN Circular 22503
Subject
GRB180316A: MASTER-IAC OT light curve
Date
2018-03-16T07:15:51Z (7 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, V.Kornilov, E.Gorbovskoy, P.Balanutsa, V.Vladimirov,
A.Krylov, I.Gorbunov, A.Kuznetsov, V.Chazov, D. Kuvshinov, D.Zimnukhov
(Lomonosov Moscow State University, SAI),
R. Rebolo, M. Serra-Ricart
(The Instituto de Astrofisica de Canarias),
R.Podesta, C.Lopez, F. Podesta
(Observatorio Astronomico Felix Aguilar (OAFA),National University of San Juan,
Argentina),
H. Levato, C. Saffe
(Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San
Juan, Argentina),
D.Buckley, S. Potter
(South African Astronomical Observatory),
O.Gres, N.M.Budnev
(Irkutsk State University),
A. Tlatov, V.Senik, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory)
V.Yurkov, A.Gabovich, Yu.Sergienko
(Blagoveschensk Educational State University, Blagoveschensk),
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in
IAC was pointed to the GRB180316A (Melandri et al GCN22500)
15 sec after notice time and 44 sec after trigger time at 2018-03-16 04:58:09
UT .
There is OT(GCN 22502) as the GRB counterpart coordinates
(17h 41m 42s.82, + 00d 44m 53s.6 )
error =+-0.5"
The automatical OT light curve available at
http://master.sai.msu.ru/static/OT/LC_GRB180316A.png
The message may be cited.
====================================================================
The observations made on zenit distance = 42 degrees, galaxy latitude b = 15
degree.
The moon ( 2 % bright part) below the horizon (The altitude of the Moon is -22
degree ).
The sun altitude is -30.4 degree.
The object can be observed till sunrise at 2018-03-16 07:14:55
GCN Circular 22504
Subject
GROND observations of GRB 180316A
Date
2018-03-16T10:40:27Z (7 years ago)
From
Patricia Schady at MPE/Swift <pschady@mpe.mpg.de>
P. Schady and S. Steinmassl (both MPE) report:
We observed the field of GRB 180316A (Swift trigger 814677; Melandri et
al., GCN #22500) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 06:46 UT on March 16, 1.8 hours after the GRB
trigger. They were performed at an average seeing of 1.5" and at an
average airmass of 1.5.
We clearly detect the NIR/optical transient of GRB 180316A within the
enhanced XRT position (Evans et al., GCN #22501), in agreement with the
optical transient detected with MASTER (Lipunov et al., GCN #22502,
#22503). Based on the first 4 minutes of exposure, we measure the
following magnitudes (all in AB system):
g' = 19.4 +/- 0.1 mag
r' = 19.0 +/- 0.1 mag
i' = 18.9 +/- 0.1 mag
z' = 18.8 +/- 0.1 mag
J = 18.2 +/- 0.1 mag
H = 18.0 +/- 0.1 mag
K = 17.8 +/- 0.2 mag
Given magnitudes are calibrated against GROND zeropoints in g'r'i'z' and
2MASS field stars in JHK, and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.24 in the
direction of the burst (Schlafly & Finkbeiner 2011).
We acknowledge the excellent support from the TiO and the current observer
at the 2.2m in La Silla, Sam Kim and Charlotte Brand.
GCN Circular 22507
Subject
GRB 180316A: LCO Cerro Tololo observations
Date
2018-03-16T12:10:56Z (7 years ago)
From
Renato Martone at Universita' di Ferrara <mrtrnt@unife.it>
R. Martone, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large collaboration report:
We observed the field of Swift GRB180316A (Melandri et al., GCN 22500) on March 16, from 07:38 to 07:59 UT (mid time of 0.12 days post burst) with a 1-m unit LCO telescope in Cerro Tololo in the SDSS r��� i' filters. We detect the optical afterglow (Lipunov et al., GCN 22502; Schady and Steinmassl, GCN 22504) with the following magnitudes:
Mid time since GRB Exp Filter Magnitude
(days) (s)
-------------------------------------------------------------
0.11 4x120 SDSS-R 19.04 +- 0.05
0.12 4x120 SDSS-I 18.88 +- 0.05
-------------------------------------------------------------
as calibrated against nearby SDSS stars.
GCN Circular 22508
Subject
GRB 180316A: Enhanced Swift-XRT position
Date
2018-03-16T14:26:58Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 4963 s of XRT Photon Counting mode data and 8 UVOT
images for GRB 180316A, 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 = 265.42854, +0.74813 which is equivalent
to:
RA (J2000): 17h 41m 42.85s
Dec (J2000): +00d 44' 53.3"
with an uncertainty of 1.4 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 22509
Subject
GRB 180316A: RATIR Optical Observations
Date
2018-03-16T14:37:38Z (7 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 180316A (Melandri, et al., GCN 22500) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2018/03 16.39 to 2018/03 16.52 UTC (4.34 to
7.49 hours after the BAT trigger), obtaining a total of 2.29 hours exposure
in the r and i bands.
The afterglow is well-detected within the Swift-XRT error circle (Evans, et
al., GCN 22501). In comparison with the USNO-B1 catalog, we obtain:
r = 20.07 +/- 0.02
i = 19.87 +/- 0.02
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source appears so fade in flux
with time as t^(-1.4+/-0.1).
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 22510
Subject
GRB 180316A: Swift/UVOT Detection
Date
2018-03-16T15:48:27Z (7 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and A. Melandri (INAF-OAB) report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180316A
105 s after the BAT trigger (Melandri et al., GCN Circ. 22500).
A fading source consistent with the enhanced XRT position (Evans et al.
GCN Circ. 22508) and the optical transient reported by Lipunov et al.
(GCN Circ. 22503), Shady & Steinmassl (GCN Circ. 22504) and Martone et
al. (GCN Circ. 22507), Butler et al. (GCN Circ. 22509) is detected in
the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 17:41:42.87 = 265.42861 (deg.)
Dec (J2000) = +00:44:53.7 = 0.74824 (deg.)
with an estimated uncertainty of 0.42 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 finding chart (white_fc) and early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_fc 105 254 147 16.27 �� 0.03
white 596 616 20 17.40 �� 0.11
v 646 839 39 17.15 �� 0.18
b 572 592 20 17.40 �� 0.15
u 317 566 246 16.44 �� 0.04
w1 695 22410 1175 >20.4
m2 12527 12578 50 >19.2
w2 622 6753 255 >19.5
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.28 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 22511
Subject
GRB 180316A: Swift-XRT refined Analysis
Date
2018-03-16T15:57:42Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.
Tohuvavohu (PSU) and A. Melandri report on behalf of the Swift-XRT
team:
We have analysed 6.1 ks of XRT data for GRB 180316A (Melandri et al.
GCN Circ. 22500), from 101 s to 28.6 ks after the BAT trigger. The
data comprise 534 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. 22501).
The late-time light curve (from T0+4.4 ks) can be modelled with an
initial power-law decay with an index of alpha=-0.0 (+/-0.6), followed
by a break at T+8729 s to an alpha of 2.1 (+/-0.3).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+0.07, -0.04). The
best-fitting absorption column is 2.038 (+0.286, -0.012) x 10^21
cm^-2, consistent with the Galactic value of 2.0 x 10^21 cm^-2
(Willingale et al. 2013). The PC mode spectrum has a photon index of
2.05 (+/-0.16) and a best-fitting absorption column of 3.3 (+/-0.7) 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 (5.7 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 3.3 (+/-0.7) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^21 cm^-2
Excess significance: 3.2 sigma
Photon index: 2.05 (+/-0.16)
If the light curve continues to decay with a power-law decay index of
2.1, the count rate at T+24 hours will be 2.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.7 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00814677.
This circular is an official product of the Swift-XRT team.
GCN Circular 22512
Subject
GRB 180316A: Swift-BAT refined analysis
Date
2018-03-16T19:49:29Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), A. Melandri (INAF-OAB),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180316A (trigger #814677)
(Melandri et al., GCN Circ. 22500). The BAT ground-calculated position is
RA, Dec = 265.422, 0.737 deg which is
RA(J2000) = 17h 41m 41.3s
Dec(J2000) = +00d 44' 14.3"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 29%.
The mask-weighted light curve shows a main structure with several overlapping
pulses that starts at ~ T-15 s and ends at ~ T+30 s. The major peak occurs at
~ T+1 s. In addition, there are some weak emission before the main structure
that starts at ~ T-80 s, and a weak tail afterward that lasts until ~ T+40 s.
T90 (15-350 keV) is 87.0 +- 20.6 sec (estimated error including systematics).
The time-averaged spectrum from T-79.73 to T+37.27 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.46 +- 0.12. The fluence in the 15-150 keV band is 4.9 +- 0.4 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+1.27 sec in the 15-150 keV band
is 3.3 +- 0.5 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
GCN Circular 22514
Subject
GRB 180316A: RATIR Optical Observations, Possible Re-brightening
Date
2018-03-17T15:19:48Z (7 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 180316A (Melandri,, et al., GCN 22500) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on
the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional
on Sierra San Pedro M��rtir from 2018/03 17.39 to 2018/03 17.52 UTC (28.35
to 31.55 hours after the BAT trigger), obtaining a total of 2.36 hours
exposure in the r and i bands.
The optical afterglow (e.g., Lipunov, et al., GCN 22502) is again cleanly
detected. In comparison with the USNO-B1 catalog, we obtain:
r = 20.23 +/- 0.02
i = 19.93 +/- 0.01
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. These magnitudes are comparable to
those reported for RATIR for 2018/03.16 (Butler, et al., GCN 22509).
During that observation, the afterglow was fading strongly. We again
observe the afterglow to be fading, as t^(-0.7+/-0.3), and we infer that
the afterglow may have brightened between our epochs, at a time around 1
day after the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 22516
Subject
GRB 180316A: TSHAO optical observations
Date
2018-03-18T18:33:32Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva
(FAPHI), E. Mazaeva (IKI), M. Krugov (FAPHI) report on behalf of larger
GRB follow-up collaboration:
We observed the field of GRB GRB 180316A (Melandri et al., GCN 22500)
with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory
starting on Mar. 17 (UT) 23:19:40. We obtained several images in
R-filter. The optical afterglow (Lipunov et al., GCN 22502; Schady et
al. GCN 22504; Martone et al. GCN 22507; Butler et al., GCN 22509;
Breeveld et al. GCN 22510) is marginally detected in a stacked image.
Preliminary photometry of the field is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-03-17 23:19:40 1.78280 R 36*60 21.5 0.5 21.0
The photometry is based on several nearby USNO-B1.0 stars.
GCN Circular 22517
Subject
GRB 180316A: MITSuME Okayama optical upper limits
Date
2018-03-19T07:23:59Z (7 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. L. Murata, R. Itoh, T. Yoshii, Y. Tachibana, S. Harita, K. Morita, T.
Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180316A (A. Melandri et
al., GCN Circular #22500) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Okayama Astrophysical
Observatory, Japan.
The observation started on 16:19:04 UT. We did not find any new point
source within enhanced XRT circle (P.A. Evans et al., GCN Circular #22508)
in all three bands.
We obtained following limits for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------------
-------------------------------------------
12.22 19:44:32 1980 >17.3 >17.4 >17.4
------------------------------------------------------------
-------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 22518
Subject
GRB 180316A: MITSuME Akeno optical upper limits
Date
2018-03-19T07:26:57Z (7 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. L. Murata, R. Itoh, T. Yoshii, Y. Tachibana, S. Harita, K. Morita, T.
Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180316A (A. Melandri et
al., GCN Circular #22500) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.
The observation started on 16:39:08 UT. We did not find any new point
source within enhanced XRT circle (P.A. Evans et al., GCN Circular #22508)
in all three bands.
We obtained following limits for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------------
-------------------------------------------
11.71 18:28:36 11620 >20.6 >19.7 >18.9
------------------------------------------------------------
-------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 22519
Subject
GRB 180316A: RATIR Optical Observations
Date
2018-03-19T14:38:20Z (7 years ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and
Vicki Toy (UMD) report:
We observed the field of GRB 180316A (Melandri et al., GCN 22500) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico
Nacional on Sierra San Pedro M��rtir from 2018/03 19.38 to 2018/03 19.52
UTC (76.23 to 79.44 hours after the BAT trigger), obtaining a total of
2.44 hours exposure in the r and i bands.
For a source within the Swift-XRT error circle, in comparison with the
USNO-B1 and 2MASS catalogs, we obtain the following 3-sigma upper
limits:
r > 23.72
i > 23.59
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 22548
Subject
Konus-Wind observation of GRB 180316A
Date
2018-03-26T15:10:45Z (7 years ago)
From
Anastasia Tsvetkova at Ioffe Institute <tsvetkova@mail.ioffe.ru>
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 180316A
(Swift detection of a burst: Melandri et al., GCN 22500;
Cummings et al., GCN 22512)
triggered Konus-Wind at T0=17845.869 s UT (04:57:25.869).
The burst light curve shows a single emission episode
which starts at ~T0-13 s and has a total duration of ~29 s.
The emission is seen up to ~1.2 MeV.
As observed by Konus-Wind, the burst
had a fluence of 1.43(-0.21,+0.38)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+2.976 s,
of 2.77(-1.16,+1.49)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+16.640 s)
is best fit in the 20 keV - 1.2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -1.23(-0.23,+0.27),
and Ep = 439(-139,+424) keV (chi2 = 74/60 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -1.87 (chi2 = 74/59 dof).
The spectrum near the peak count rate
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model
with�� alpha = -1.19(-0.22,+0.26),
and Ep = 498(-165,+498) keV (chi2 = 54/61 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -1.75 (chi2 = 53/60 dof).
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180316_T17845/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.