James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), G=
ayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) rep=
ort:
Swift/BAT did not localize GRB 241107A onboard (T0: 2024-11-07T23:30:00.1 =
UTC, SVOM/GRM GCN 38125).
3 seconds of TTE data is available covering the time of this burst, associa=
ted with BAT failed trigger #1266248, as the burst triggered BAT's rate tri=
gger algorithm, but failed to localize the burst onboard. There is no long =
duration GUANO data available for this burst due to lack of prompt notice f=
rom other instruments.
The burst is seen clearly in the BAT rates light-curve, but we fail to reco=
ver it in an image.=20
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, =
169), typically requires ~40 s of off-time TTE data to properly fit the bac=
kground, but here we attempt to approximate the background model with ~2.5 =
s of TTE data around the burst.=20
NITRATES detects the burst in a 0.2 s analysis time bin with a sqrt(TS) of =
35.2.=20
An arcminute localization candidate is found with a DeltaLLHPeak of 10.3 an=
d DeltaLLHOut of 2.5.=20
Due to limited data, nonstandard fitting was used, so the position is indep=
endently not highly confident, but matches both the IPN (GCN 38165) and INT=
EGRAL/IBIS (GCN 38172) localizations.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descr=
iptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
The BAT candidate position is
RA, Dec =3D 111.325, -24.487 deg which is
RA(J2000) =3D 07h 25m 18.0s
Dec(J2000) =3D -24 29=E2=80=B2 13.2=E2=80=B3
with an estimated uncertainty of 4 arcmin radius.
GCN Circular #38187
T. Mohan, G. Waratkar, A.P. Saikia, V. Swain, R. Kumar, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of the GRB 241107A (SVOM/GRM team, GCN 38125, Rodi et al., GCN 38164, IPN GCN 38165) with the 0.7m GROWTH-India Telescope (GIT). Once arcminute positions became available (Mereghetti et al., GCN 38172 and DeLaunay et al., GCN 38177), we started observations at 2024-11-12 20:10:35 UT, about 4.8 days after the trigger. We obtained multiple images of 360s each in r' and i' filters. We did not detect any new source in our stacked image around the coordinates given by INTEGRAL IBIS or Swift BAT.
Below is the upper limit in the stacked images:
---------------------------------------------------------------------------------
| MJD (mid) | Filter | Exposure (s) | Limiting Magnitude (AB) |
| ----------- | ------ | ------------ | ----------------------- |
| 60626.85364 | r' | 6x360 | 20.8 |
| 60626.87984 | i' | 6x360 | 20.6 |
---------------------------------------------------------------------------------
The magnitude is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular #38205
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short GRB 241107A (SVOM/GRM detection: Wang et al., GCN 38125;
INTEGRAL/IBIS/PICsIT detection: Rodi et al., GCN 38164;
IPN triangulation: Kozyrev et al., GCN 38165;
INTEGRAL IBIS localization: Mereghetti et al., GCN 38172;
Swift/BAT candidate arcminute localization: DeLaunay et al.: GCN 38177)
triggered Konus-Wind (KW) at T0=84602.493 s UT (23:30:02.493).
The burst light curve starts with a bright, multi-peaked emission pulse
with a duration of ~0.028 s, which is followed by a weaker, decaying emission.
The total duration of the burst is ~0.160 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB241107_T84602/
As observed by Konus-Wind, the burst had
a total fluence of 1.43(-0.33, +0.13)x10^-6 erg/cm^2 and
a 16-ms peak energy flux, measured from T0-0.096 s,
of 3.6 (-1.2, +0.2)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
Since the bulk of the burst emission was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.
The time-averaged spectrum of the burst (measured from T0-0.048 s to T0+0.080 s)
is best fit by a blackbody (BB) function with kT(BB) = 193 (-18, +20) keV.
This spectrum can be also described by a power law with
exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with a hard photon index alpha = 1.32(-1.09,+2.7) and Ep = 760(-91,+390) keV.
The spectrum of the initial pulse alone (measured from T0-0.112 s to T0-0.080 s)
is best described by a blackbody function with kT(BB) = 251 (-31, +38) keV.
The fluence in this pulse is 1.15(-0.38, +0.06)x10^-6 erg/cm^2, or ~80%
of the total fluence.
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.
Previous IAU Circulars 