GRB 240129A
GCN Circular 35653
Subject
GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
Date
2024-01-30T18:32:45Z (a year ago)
From
Jimmy DeLaunay at Penn State <delauj2@gmail.com>
Via
Web form
James DeLaunay (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 240129A onboard (T0: 2024-01-29T15:09:22.53 UTC, Fermi trig 728233767)
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 15.8 in a 16.384 s analysis time bin, starting at T0 - 4.096 s.
NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of 2.4.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN Circular 35655
Subject
GRB 240129A: Fermi GBM Observation
Date
2024-01-31T15:28:04Z (a year ago)
From
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov>
Via
Web form
S. Dalessi (UAH), V Sharma (NASA-GSFC/UMBC) and C. Meegan (UAH) report
on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 15:09:22.53 UT on 29 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240129A (trigger 728233767/240129632), which was also
detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35653).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 108.02, Dec = 34.60 (J2000 degrees, equivalent to
J2000 07h 12m, 34d 36'), with a statistical uncertainty of 3.18 degrees.
(radius, 1-sigma containment, statistical only; there is additionally a
systematic error which we have characterized as a core-plus-tail model,
with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger
than 10 deg systematic error [Connaughton et al. 2015, ApJS, 216, 32]).
The angle from the Fermi LAT boresight is 114 degrees.
The GBM light curve of a single emission episode with a duration (T90)
of about 28 s (50-300 keV). The time-averaged spectrum
from T0+6.1 to T0+21.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.24 +/- 0.09 and the cutoff energy,
parameterized as Epeak, is 74 +/- 6 keV.
The event fluence (10-1000 keV) in this time interval is
(4.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.38 s in the 10-1000 keV band is 4.9 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/."
GCN Circular 39130
Subject
GRB 240129A: further SAO RAS optical observations
Date
2025-02-03T14:10:39Z (4 months ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
Via
Web form
A. Moskvitin, R. Uklein, Yu. Sotnikova (SAO RAS),
A. Ghosh, S. Razzaque (CAPP, University of Johannesburg)
report on behalf of the GRB follow-up team.
We observed the field of GRB 250129A (Beardmore et al., GCN 39066;
Goad et al., GCN 39082; Frederiks et al., GCN 39116) with the SAO RAS
1-m telescope Zeiss-1000 equipped with the multi-mode focal reducer
MAGIC on 2025 February 2, 01:23:43--01:43:23 UT (t_mid - T0 = 3.8669
days). We obtained 3 x 300 sec. images in R band.
The OT (Francile et al., GCN 39065; GCN 39075, Beardmore et al.,
GCN 39066, Schneider et al., GCN 39071, Belkin et al., GCN 39072;
Izzo et al., GCN 39073; Izzo and Malesani, GCN 39074; Ghosh et al.,
GCN 39077; Schneider et al., GCN 39078; Brivio et al., GCN 39079;
Siegel and Beardmore, GCN 39085; Zheng and Filippenko, GCN 39090;
GCN 39102; Schlekat et al., GCN 39091; Antier et al., GCN 39096;
Odeh et al., GCN 39097; Ferro et al., GCN 39098; Bochenek and Perley,
GCN 39099; Malesani et al., GCN 39100; Romanov, GCN 39101;
Watson et al., GCN 39104; Vinko et al., GCN 39105; Akl et al.,
GCN 39106; Moskvitin et al., GCN 39107; Calapai GCN 39109;
Schlekat et al., GCN 39110; Gompertz et al., GCN 39114; Ror et al.,
GCN 39115; Lipunov et al., GCN 39119; Wu et al., GCN 39124;
Paek et al., GCN 39129) is clearly detected in our stacked image
with the brightness of R = 21.06 +/- 0.14 (calibrated against R2
magnitudes of nearby UNSO-B1 stars and not corrected for the MW
extinction).