HAWC-190916A
GCN Circular 25779
Subject
Correction on name for HAWC-190916A to HAWC-190917A
Date
2019-09-18T20:28:20Z (7 years ago)
From
Hugo Ayala at Pennsylvania State University <hgayala@psu.edu>
Due to the reported correction on the trigger time of the HAWC Burst Alert
to
September 17 2019, 01:14:19 UT,
the HAWC collaboration decided to change the name of the event to be in
accordance with the UTC date.
The name will be now HAWC-190917A.
First circular: https://gcn.gsfc.nasa.gov/gcn3/25766.gcn3
Second circular: https://gcn.gsfc.nasa.gov/gcn3/25768.gcn3
Related circulars that followed-up the alert:
https://gcn.gsfc.nasa.gov/gcn3/25769.gcn3
https://gcn.gsfc.nasa.gov/gcn3/25772.gcn3
https://gcn.gsfc.nasa.gov/gcn3/25774.gcn3
https://gcn.gsfc.nasa.gov/gcn3/25775.gcn3
https://gcn.gsfc.nasa.gov/gcn3/25776.gcn3
Hugo Ayala,
On behalf of the HAWC Collaboration
GCN Circular 25776
Subject
HAWC-190916A: Upper limits from Insight-HXMT/HE observations
Date
2019-09-18T15:03:30Z (7 years ago)
From
Shuo Xiao at IHEP <xiaoshuo@ihep.ac.cn>
S. Xiao, Y. G. Zheng, C. Cai, Q. Luo, Q. B. Yi,
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang,
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
Insight-HXMT was taking data normally around the trigger time
(T0=2019-09-16T01:14:19 UTC) of HAWC-190916A event
(GCN #25766), which was monitored without any occultation by
the Earth.
Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are
found in a search of the Insight-HXMT/HE raw light curves.
Assuming the counterpart GRB with three typical GRB Band spectral
models, two typical duration timescales (1 s, 10 s) from the center
of the position of the alert is (RA=321.84 deg, DEC=30.97 deg),
the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are
reported below:
Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1 s: 3.1e-07 erg cm^-2
10 s: 1.2e-06 erg cm^-2
Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s: 3.9e-07 erg cm^-2
10 s: 1.5e-06 erg cm^-2
Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s: 3.0e-07 erg cm^-2
10 s: 1.4e-06 erg cm^-2
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the spacecraft.
Insight-HXMT is the first Chinese space X-ray telescope, which was
funded jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information could be found at: http://www.hxmt.org.
GCN Circular 25775
Subject
HAWC-190916A: IceCube neutrino search
Date
2019-09-18T03:22:35Z (7 years ago)
From
Alex Pizzuto at ICECUBE/U of Wisconsin <pizzuto@wisc.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search for track-like muon neutrino events arriving from the position of HAWC-190916A (GCN 25766, 25768) in a time window 12 hours in duration centered on the burst time (2019-09-16 19:14:19.000 UTC to 2019-09-17 07:14:19.000 UTC). 1 track-like event is found in spatial coincidence with HAWC-190916A
during this time period. This represents a p-value of 0.044 (1.7 sigma) with respect to an atmospheric background only hypothesis. Accordingly,
this event would represent a time-integrated muon-neutrino flux normalization upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 5.2 x 10^-5 TeV cm^-2 for this observation period. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum are between approximately 1 TeV and 500 TeV.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu.
GCN Circular 25774
Subject
HAWC-190916A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
Date
2019-09-17T20:13:17Z (7 years ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
Antonio Martin-Carrillo (UCD), Francesca Onori
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)
on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration
Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed
a search for a prompt gamma-ray counterpart of HAWC-190916A (GCN
25766, 25768).
At the time of the event (2019-09-17 01:14:19 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 114 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (5.8% of optimal) response of ISGRI, strongly suppressed
(32% of optimal) response of IBIS/Veto, and somewhat suppressed (55%
of optimal) response of SPI-ACS.
The background within +/-300 seconds around the event was very stable
(excess variance 1.2).
We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]) data.
We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 3.3e-07 erg/cm^2 (within the
50% probability containment region of the source localization) for a
burst lasting less than 1 s with a characteristic short GRB spectrum
(an exponentially cut off power law with alpha=-0.5 and Ep=600 keV)
occurring at any time in the interval within 300 s around T0. For a
typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and
Ep=300 keV), the derived peak flux upper limit is ~2.9e-07 (8.8e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
We report for completeness and in order of FAP, all excesses
identified in the search region. We find: 2 likely background
excesses:
scale | T | S/N | flux ( x 1e-06 erg/cm2/s) | FAP
0.65 | 80.8 | 4 | 0.52 +/- 0.134 +/- 0.189 | 0.417
0.75 | 184 | 4.2 | 0.523 +/- 0.124 +/- 0.191 | 0.646
Note that FAP estimates (especially at timescales above 2s) may be
possibly further affected by enhanced non-stationary local background
noise. This list excludes any excesses for which FAP is close to
unity.
All results quoted are preliminary.
This circular is an official product of the INTEGRAL Multi-Messenger
team.
[1] Savchenko et al. 2017, A&A 603, A46
[2] Savchenko et al. 2012, A&A 541A, 122S
GCN Circular 25772
Subject
HAWC-190916A: Upper limits from Fermi-GBM Observations
Date
2019-09-17T17:50:53Z (7 years ago)
From
Joshua Wood at MSFC/Fermi-GBM <joshua.r.wood@nasa.gov>
J. Wood (NASA/MSFC) reports on behalf of the Fermi GBM Team:
For HAWC-190916A, Fermi-GBM was observing the full localization region at event time.
There was no Fermi-GBM onboard trigger around the event time of HAWC-190916A (GCN 25766 and 25768). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around trigger time, and also identified no counterpart candidates.
We therefore set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV (in units of 10^-7 erg/s/cm^2):
Timescale Soft Normal Hard
------------------------------------
0.128 s: 1.5 2.3 4.9
1.024 s: 0.6 0.9 1.9
8.192 s: 0.2 0.4 0.7
GCN Circular 25769
Subject
HAWC-190916A: DDOTI Optical Observations
Date
2019-09-17T04:39:42Z (7 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Eleonora Troja (GSFC/UMD), Rosa L.
Becerra (UNAM), Simone Dichiara (GSFC/UMD), Diego Gonzalez (UNAM), Alexander
Kutyrev (GSFC/UMD), William H. Lee (UNAM), Margarita Pereyra
<mpereyra@astro.unam.mx> (UNAM), and Tanner Wolfram (ASU) report:
We observed the field of HAWC-190916A (Ayala, GCN Circ 25766, 25768) with the
DDOTI wide-field imager at the Observatorio Astronomico Nacional on Sierra San
Pedro Martir (http://ddoti.astroscu.unam.mx) from 2019-09-17 03:14 to 2019-09-17
04:17 UTC (2.0 to 3.1 hours after the trigger).
We obtained a total of 2340 seconds of exposure in the w filter. We calibrated
our images against the APASS catalog. Our 10-sigma limiting magnitude is w =
19.5.
Comparing our 10-sigma detections against the USNO-B1 catalog, we detect no
reliable uncataloged sources with significant fading within 1.7 degrees of the
nominal coordinates.
We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
GCN Circular 25768
Subject
Correction on the Trigger Date HAWC-190916A --> HAWC-190917A
Date
2019-09-17T03:10:18Z (7 years ago)
From
Hugo Ayala at Pennsylvania State University <hgayala@psu.edu>
The HAWC Collaboration reported recently a HAWC Burst alert.
The reported date has a mistake. The trigger time should be:
September 17 2019, 01:14:19 UT
First circular: https://gcn.gsfc.nasa.gov/gcn3/25766.gcn3
Hugo Ayala,
In behalf of the HAWC collaboration.
[GCN OPS NOTE(22sep19): "--> HAWC-190917A" was added to the SUBJECT-line.]