GRB 200306C
GCN Circular 27326
Subject
GRB 200306C: Swift detection of a burst with an optical counterpart
Date
2020-03-06T23:02:02Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
J.D. Gropp (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
J. A. Kennea (PSU), S. Laha (GSFC/UMBC/CRESST),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), B. Sbarufatti (PSU), M. H. Siegel (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 22:50:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200306C (trigger=960102). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 198.582, +11.255 which is
RA(J2000) = 13h 14m 20s
Dec(J2000) = +11d 15' 18"
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 50 sec. The peak count rate
was ~1800 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 22:52:35.9 UT, 116.9 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 198.55562, 11.26981 which
is equivalent to:
RA(J2000) = 13h 14m 13.35s
Dec(J2000) = +11d 16' 11.3"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 107 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
https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.91 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.8
(+2.73/-2.37) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 250 seconds with the U filter starting
117 seconds after the BAT trigger. There is a candidate afterglow in the list
of sources generated on-board at
RA(J2000) = 13:14:13.44 = 198.55602
DEC(J2000) = +11:16:11.5 = 11.26985
with a 90%-confidence error radius of about 1.10 arc sec. This position is 1.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.47. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.02.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu).
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/)
GCN Circular 27328
Subject
GRB 200306C: FRAM-ORM afterglow detection
Date
2020-03-06T23:48:16Z (5 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Martin Jelinek, Jan Strobl (ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain)
reacted robotically to the alert of GRB200306C (Gropp
et al GCNC 27326), obtaining a series of 20 s unfiltered
images starting at 22:51:39.3 UT, i.e. 60.3s post trigger.
We clearly detect the source reported by (Gropp et al
GCN 27326 and Lipunov et al GCN 27325), decaying at a
rate of alpha ~ 1.4 +- 0.1. The brightness of the object
was R = 14.1 the first image.
GCN Circular 27329
Subject
GRB 200306C: BOOTES-1 detection of the optical afterglow
Date
2020-03-07T00:04:48Z (5 years ago)
From
Alberto J. Castro-Tirado at IAA-CSIC <ajct@iaa.es>
Y.-D. Hu, A. J. Castro-Tirado and E. Fernandez-Garcia (IAA-CSIC), C.
Perez del Pulgar, A. Reina, A. Castellon, I. Carrasco, I. Perez-Garcia
(UMA), F. Rendon (IAA-CSIC and INTA-CEDEA), on behalf of a larger
collaboration, report:
The 30cm BOOTES-1 robotic telescope at INTA-CEDEA in Huelva (Spain)
automatically responded to the Swift trigger of GRB 200306C (Gropp et
al., GCNC 27326). A sequence of 1-s images (clear filter) were obtained
starting at 22:52:28 UT (i.e. 109s after the burst). At the UVOT
position reported by Swift an optical transient is detected with R =
14.9, in agreement with the MASTER (Lipunov et al. GCNC 27324) and FRAM
detections (Jelinek et al. GCNC 27328). A detailed analysis for the
sequence of images which were obtained is ongoing. The magnitude is
calibrated against the USNO-B1 catalog and is not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff at INTA-CEDEA for its excellent support.
GCN Circular 27332
Subject
GRB 200306C: GOTO upper limits
Date
2020-03-07T00:57:36Z (5 years ago)
From
Kendall Ackley at Monash University <kendall.ackley@monash.edu>
K. Ackley (1); K. Wiersema (2); Y.-L. Mong (1); D. K. Galloway (1);
D. Steeghs (2); V.Dhillon (3); P. O'Brien (4); G. Ramsay (5);
D. Pollacco (2); E. Thrane (1); S. Poshyachinda (6); R. Kotak (7);
L. Nuttall (8); E. Pall\'e (9); K. Ulaczyk (2); J. Lyman (2);
R. Cutter (2); A. Levan (2); T. Marsh (2); R. West (2); E. Stanway (2);
B. Gompertz (2); T. Killestein (2); A. Casey (1); M. Brown (1);
B. Muller (1); M. Dyer (3); J. Mullaney (3); E. Daw (3);
S. Littlefair (3); J. Maund (3); L. Makrygianni (3); U. Burhanudin (3);
R. Starling (4); R. Eyles (4); S. Tooke (4); S. Aukkaravittayapun (6);
U. Sawangwit (6); S. Awiphan (6); D. Mkrtichian (6); P. Irawati (6);
S. Mattila (7); T. Heikkil\"a (7); E. Rol (1)
((1) Monash University, (2) Warwick University, (3) University of
Sheffield, (4) University of Leicester, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of Thailand,
(7) University of Turku, (8) University of Portsmouth, (9) Instituto
de Astrofisica de Canarias)
report on behalf of the GOTO collaboration:
We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to GRB 2000306C
(Palmer et al. 2020; GCN #27326).
We made a series of 9x60 s exposures using our wide L-band filter
(400-700 nm) covering the Swift UVOT position (Palmer et al. 2020; GCN
#27326), starting at 1.1 hours after the Swift BAT trigger with
midtime 23:56:45 UT on 06 March 2020.
Using a difference imaging analysis with recent survey observations
of the same pointings as reference, we do not identify the detections
from MASTER (Lipunov et al. GCN #27324), FRAM (Jelinek et al. GCN #27328),
and BOOTES-1 (Castro-Tirado et al. GCN #27329). Our mean 5-sigma detection
limit was g=19.1 mag based on PS1 catalogue calibrators.
GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org)
GCN Circular 27333
Subject
GRB 200306C: SAO RAS observations of OT
Date
2020-03-07T01:20:14Z (5 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. Moskvitin on behalf of the larger GRB follow-up team report.
We observed the field of the GRB 200306C (Gropp et al. GCNC #27326)
with the 1-m telescope of SAO RAS in BVRc filters. The observations
were started in semi-automatic mode since 2 minutes after the trigger.
We clearly detected the OT discovered by Swift/UVOT, MASTER-Net
(Lipunov et al. GCNC #27324/27325/27327), FRAM-ORM (Jelinek et al.
GCNC #27328), BOOTES-1 (Hu et al., GCNC #27329) with the coordinates:
R. A. = 13:14:13.44, Decl. = +11:16:11.8 +/- 0".5, Epoch = 2000.0.
Preliminary R band photometry of the OT:
Tmid-T0, s exp., s Rmag +/- err
151 30 15.29 +/- 0.06
183 30 15.77 +/- 0.03
230 30 15.97 +/- 0.12
276 30 16.14 +/- 0.04
388 60 16.49 +/- 0.05
464 60 16.69 +/- 0.07
541 60 16.99 +/- 0.04
The calibration were done against nearby SDSS stars (Lupton, 2005).
GCN Circular 27334
Subject
GRB 200306C: Liverpool Telescope observations
Date
2020-03-07T02:09:10Z (5 years ago)
From
Luca Izzo at DARK/NBI <luca.izzo@gmail.com>
L. Izzo (DARK/NBI) and D. Perley (LJMU) report:
We observed GRB 200303C (Gropp et al. GCN 27326) with the IO:O camera mounted on the 2-m Liverpool Telescope located in La Palma, Spain. Observations started on March 7th at 01:01:49 UT (2.20 hours after the GRB trigger) and we obtained a series of 5x60s images in the griz filters.
In our stacked i-band and z-band images we detect the afterglow at the position reported by Swift-UVOT and other telescopes (Lipunov et al. GCNC 27324, GCN 27325; Jelinek et al. GCN 27328; Hu et al., GCN 27329; Moskvitin GCN 27333) and we measure a preliminary magnitude of i(AB) = 20.7 +- 0.1 mag (median time 2.46 hr after the GRB trigger) and z(AB) = 21.0 +- 0.3 mag (median time 2.58 hr after the GRB).
[GCN OPS NOTE(07mar20): Per author's request, in the first sentence "200303A" was changed to "200303C".
Also per request, the thrid paragraph was removed as it was an accidental inclusion of a previous circular.]
GCN Circular 27335
Subject
GRB 200306C: OSN 1.5m afterglow detection
Date
2020-03-07T02:51:33Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann, M. Blazek (both HETH/IAA-CSIC), A. de Ugarte Postigo
(HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, J. F. Agui Fernandez (both
HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:
We observed the optical afterglow position of GRB 200306C (Lipunov et
al., GCNs #27324, #27325; Gropp et al., GCN #27326; Jelinek et al., GCN
#27328; Hu et al., GCN #27329; Moskvitin, GCN #27333; Izzo & Perley, GCN
#27334) with the 1.5m telescope of the Sierra Nevada Observatory,
Granada, Spain, in the V filter. Observations began 46 minutes after the
GRB, and we obtained 18 x 30 s images under moonlight. We also obtained
four Rc images before technical problems shut down the telescope, but
stray light from a nearby bright star precludes a detection.
We detect the afterglow in a stacked image centered 0.03985 days after
the GRB, at V = 19.38 +/- 0.14 mag (Vega mag).
The afterglow magnitude was measured against six comparison stars from
the GSC 2.3 catalog.
GCN Circular 27337
Subject
GRB 200306C: LCO Optical Upper Limits
Date
2020-03-07T07:28:15Z (5 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@uvi.edu>
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
We observed Swift GRB 200306C (Gropp et al., GCN 27326) with the LCO 1-m Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on March 7, from 4:50 to 5:21 UT (corresponding to 6.0 to 6.5 hours from the GRB trigger time) with the Bessel I and R filters.
We performed a series of 5x120s exposures in I and R. We do not detect any sources in the individual frames (nor in stacked images) at the location of previous optical afterglow detections (Lipunov et al., GCN 27325, Jelinek et al., GCN 27328, Castro-Tirado et al., GCN 27329, Moskvitin et al., GCN 27333, Izzo et al., GCN 27334, Kann et al., 27335). Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits:
R > 20.56
I > 19.65
R.S. is funded by NSF AST grant #1831682
GCN Circular 27338
Subject
GRB200306C: First Hour Liverpool Telescope Observations
Date
2020-03-07T09:56:23Z (5 years ago)
From
Iain Steele at Liverpool/JMU <i.a.steele@ljmu.ac.uk>
I.A.Steele (LJMU) reports on behalf of a larger collaboration:
The automated system of the Liverpool 2.0m telescope, La Palma, followed up GRB200306C starting at 23:01:37 UT (i.e. approximately 11 minutes post trigger) in the r���, i���,and z��� band filters for a period of 1 hour.
We clearly detect the afterglow reported in GCN numbers 27326, 27328, 27329, 27334 with a r��� band magnitude of 17.3 in our first frame calibrated with respect to a nearby APASS source. The afterglow continues to fade over the course of the hour.
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GCN Circular 27339
Subject
GRB 200306C: KCT upper limit of the optical afterglow
Date
2020-03-07T14:23:18Z (5 years ago)
From
Gu Lim at Seoul National U <lim9gu@gmail.com>
Gu Lim (SNU), Myungshin Im (SNU), Changbom Park (KIAS), Gregory S. H. Paek
(SNU) on behalf of GECKO
We carried out a follow-up observation of the afterglow of GRB 200306C
(Gropp et al GCNC 27326) using the 14-inch KCT (KIAS Chamnun Telescope) at
DeepSkyChile, Chile. A series of 30x120 s exposures on SDSS i-band were
obtained, starting at 04:37:13.849 UT on 06 March 2020.
We do not detect any sources on the stacked image at the previously
reported position of afterglow detections (Lipunov et al. GCN #27324, GCN
#27325, Jelinek et al. GCN #27328, Castro-Tirado et al. GCN #27329,
Moskvitin et al., GCN 27333, Izzo et al., GCN 27334, Kann et al., 27335).
After the flux calibration using SDSS dr12 photometric catalog, 5-sigma
detection limit is obtained as i > 18.40 AB magnitude.
KIAS Chamnun Telescope (KCT) is a 0.36m telescope of the Korea Institute
for Advanced Study (KIAS), recently installed at the DeepSkyChile site in
Chile. "Chamnun" is a Korean word for "True Eye", meaning the eye that can
see the truth.
Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network
of 10+ 0.5m to 1m class telescopes over the world.
���
GCN Circular 27341
Subject
GRB 200306C: VIRT optical upper limits
Date
2020-03-07T17:53:18Z (5 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
P. Gokuldass (UVI), D. Morris (UVI), N. Orange (OrangeWave Innovative
Science, LLC), A. Cucchiara (College of Marin), R. Strausbaugh (UVI) report:
We observed the field of GRB200306C (Gropp et al., GCN 27326) with the 0.5m
Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 03-07-2020 starting at 01:52:04 UT (T+3.0
hrs). We performed a series of exposures in R filter. The weather
conditions were clear during the hours of observation and the zenith angle
at the start of observations was 68 degrees and rising. We observed the
Swift XRT position with a 20'x20' field of view.
We find no new source at the position of previous optical
detections (Lipunov et al., GCN 27325, Jelinek et al., GCN 27328,
Castro-Tirado et al., GCN 27329, Moskvitin et al., GCN 27333, Izzo et al.,
GCN 27334, Kann et al., 27335) and report upper limits as follows:
T_mid ||Exposure ||Filter ||Limit
T+3.3 hrs ||1025s ||R ||18.0
T+4.0 hrs ||3360s ||R ||19.0
The limits are estimated from comparison to nearby USNO B1 stars and are
not corrected for Galactic extinction. The VIRT is still in the
commissioning phase.
This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST
Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.
GCN Circular 27342
Subject
GRB 200306C: Enhanced Swift-XRT position
Date
2020-03-07T18:07:44Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.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 1935 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 200306C, 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 = 198.55588, +11.26953 which is equivalent
to:
RA (J2000): 13h 14m 13.41s
Dec (J2000): +11d 16' 10.3"
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.
GCN Circular 27345
Subject
GRB 200306C: Swift-XRT refined Analysis
Date
2020-03-07T23:02:03Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
K.L. Page (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (ASDC), V.
D'Elia (ASDC), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea
(PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and
J.D. Gropp report on behalf of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 200306C (Gropp et al. GCN
Circ. 27326), from 101 s to 18.9 ks after the BAT trigger. The data
comprise 36 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. 27342).
The late-time light curve (from T0+5.5 ks) can be modelled with a
power-law decay with a decay index of alpha=2.2 (+0.4, -0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.56 (+0.11, -0.10). The
best-fitting absorption column is 4.1 (+3.0, -2.2) x 10^20 cm^-2,
consistent with the Galactic value of 1.9 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 4.2 x 10^-11 (4.4 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.1 (+3.0, -2.2) x 10^20 cm^-2
Galactic foreground: 1.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.56 (+0.11, -0.10)
If the light curve continues to decay with a power-law decay index of
2.2, the count rate at T+24 hours will be 4.4 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-14 (1.9 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/00960102.
This circular is an official product of the Swift-XRT team.
GCN Circular 27348
Subject
GRB 200306C: Calar Alto 2.2m upper limit
Date
2020-03-08T07:43:45Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), M. Blazek, C. C. Thoene, J. F. Agui Fernandez (all
HETH/IAA-CSIC), R. Pedro Hedrosa, and E. Gallego (both CAHA) report:
We observed the field of the afterglow of GRB 200306C (Lipunov et al.,
GCNs #27324, #27325; Gropp et al., GCN #27326; Jelinek et al., GCN
#27328; Hu et al., GCN #27329; Moskvitin, GCN #27333; Izzo &
Perley, GCN #27334; Kann et al., GCN #27335; Steele et al., GCN #27338)
with the 2.2m telescope of Calar Alto equipped with CAFOS. We obtained 4
x 720 s images in the Rc band under adverse conditions (moonlight,
passing clouds, bright star still there).
Our stacked image centred at mean epoch 1.25519 d after the GRB shows no
detection to a 3-sigma upper limit of Rc > 23.0 mag (AB). The magnitude
limit was obtained versus SDSS stars in the field.
GCN Circular 27352
Subject
GRB 200306C: Swift/UVOT Detection
Date
2020-03-09T06:03:35Z (5 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 200306C: Swift/UVOT Detection
J. D. Gropp (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200306C
118 s after the BAT trigger (Gropp et al., GCN Circ. 27326).
A fading source consistent with the positions reported by
FRAM-ORM (Jelinek et al., GCN Circ. 27238),
BOOTES-1 (Hu et al., GCN Circ. 27329),
SAO RAS (Moskvitin et al., GCN Circ. 27333)
Liverpool Telescope (Izzo et al., GCN Circ 27334)
and OSN (Kann et al., GCN Circ. 27335)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 13:14:13.46 = 198.55607 (deg.)
Dec (J2000) = +11:16:11.7 = 11.26992 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections 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
u_fc 141 390 245
16.90+-0.05
u 899 1049 147
18.39+-0.16
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 27353
Subject
GRB 200306C: Swift-BAT refined analysis
Date
2020-03-09T06:03:42Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), J.D. Gropp (PSU),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+1065 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200306C (trigger #960102)
(Gropp et al., GCN Circ. 27326). The BAT ground-calculated position is
RA, Dec = 198.577, 11.263 deg which is
RA(J2000) = 13h 14m 18.6s
Dec(J2000) = +11d 15' 47.7"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.
The mask-weighted light curve shows several overlapping pulses
that start at ~T-12 s and end at ~T+50 s. T90 (15-350 keV)
is 53.5 +- 12.8 sec (estimated error including systematics).
The time-averaged spectrum from T-12.33 to T+50.70 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
0.83 +- 0.12. The fluence in the 15-150 keV band is 2.8 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+3.45 sec in the 15-150 keV band
is 1.3 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/960102/BA/
GCN Circular 27354
Subject
GRB 200306C: ALMA 3mm upper limit
Date
2020-03-09T14:01:36Z (5 years ago)
From
Tanmoy Laskar at U of Bath <tanmoylaskar@gmail.com>
T. Laskar (University of Bath), S. Bhandari (CSIRO), K. D. Alexander
(Northwestern), E. Berger (Harvard), W. Fong (Northwestern), R. Margutti
(Northwestern), C. G. Mundell (University of Bath), and P. Schady
(University of Bath) report on behalf of a larger collaboration:
"We observed GRB 200306C (Gropp et al., GCN 27326) with the Atacama Large
Millimeter/Submillimeter Array (ALMA) at 97.5 GHz over two epochs:
(i) on 2020 March 08 beginning at 05:08:54 UT (at a mean time of 0.99 d
after the burst), and
(ii) on 2020 March 09 beginning at 05:46:00 UT (at a mean time of 2.01 d
after the burst).
No mm-band emission is detected at the optical position (Gropp et al., GCN
27326; Moskvitin, GCN 27333) in either epoch. Preliminary 3-sigma upper
limits are ~ 100 uJy and ~ 120 uJy from the individual observations and ~
80 uJy from stacking the two epochs.
We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help
with scheduling and executing these observations."