GRB 240415A
GCN Circular 36381
Subject
GRB 240415A 1.3m DFOT Optical upper limit
Date
2024-05-03T13:09:26Z (a year ago)
From
ANSHIKA GUPTA at ARIES <anshika05180@gmail.com>
Via
Web form
Anshika Gupta (ARIES), Kuntal Misra (ARIES), Atul Kumar Singh (DDUGU) and Dimple (CMI) report:
We observed the field of GRB 240415A detected by Swift (GCN 36128 ) using the 1.3m Devasthal Fast Optical Telescope (DFOT) located at the Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), Nainital, India. The observation started on 2024-04-16 at 15:29:51 UTC. Multiple frames of 300 sec exposure were acquired in the R band. We do not detect the optical afterglow (earlier reported in GCN 36122, GCN 36123, GCN 36124, GCN 36132) in the stacked image down to a limiting magnitude of 21.8. The photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.
GCN Circular 36225
Subject
GRB 240415A: Swift-XRT refined Analysis
Date
2024-04-22T07:22:59Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 5.4 ks of XRT data for GRB 240415A, from 3.3 ks to
26.8 ks after the BAT trigger. The data comprise 281 s in Windowed
Timing (WT) mode with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.97 (+/-0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.18 (+/-0.16). The
best-fitting absorption column is 2.2 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 2.5 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 3.3 x 10^-11 (4.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.2 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 2.5 x 10^20 cm^-2
Excess significance: 6.4 sigma
Photon index: 2.18 (+/-0.16)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01221874.
This circular is an official product of the Swift-XRT team.
GCN Circular 36148
Subject
GRB 240415A: Glowbug gamma-ray detection
Date
2024-04-17T14:55:09Z (a year ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240415A, which was also detected by Fermi/GBM (GCN 36107, 36134) and Swift/BAT (GCN 36108, 36143).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-04-15 06:26:52.488 with a duration of 8.2 s and a total significance of about 17.7 sigma. The light curve comprises two primary peaks at ~T0+1s and ~T0+4s.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 36143
Subject
GRB 240415A: Swift-BAT refined analysis
Date
2024-04-17T02:09:31Z (a year ago)
From
Mike Moss at NASA GSFC <mikejmoss3@gmail.com>
Via
Web form
M. J. Moss (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC),
T. Sakamoto (AGU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240415A (trigger #1221874)
(Moss, et al., GCN Circ. 36108). The BAT ground-calculated position is
RA, Dec = 129.197, 73.150 deg which is
RA(J2000) = 08h 36m 47.2s
Dec(J2000) = +73d 09' 01.7"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 60%.
The mask-weighted light curve displays a bright pulse lasting for ~15 s and
peaking at ~T0+5 s and another dim pulse of emission at ~T0+30 s.
The T90 (15-350 keV) is 30.96 +- 3.59 sec (estimated error including systematics).
The time-averaged spectrum from T-0.70 to T+37.50 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.28 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+5.09 sec in the 15-150 keV band
is 4.6 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1221874
GCN Circular 36136
Subject
GRB 240415A: Swift/UVOT Detection
Date
2024-04-16T13:38:30Z (a year ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
Via
Web form
M. H. Siegel (PSU) and M. J. Moss (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240415A
3309 s after the BAT trigger (Moss et al., GCN Circ. 36108). A source consistent
with the XRT position (Beardmore et al., GCN Circ. 36128) and the reported
optical transient (Pankov et al., GCN Circ. 36118, Moskvitin et al., GCN Circ. 36122,
Reguitti et al., GCN Circ. 36123, Schneider et al., GCN Circ. 36124, Aryan et al.,
GCN Circ. 36132) is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits 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
white 3877 4077 197 19.92 +/- 0.19
v 4287 4487 197 18.95 +/- 0.28
b 3672 3872 197 >19.2
u 3467 5040 332 18.96 +/- 0.18
w1 4698 4897 197 >19.3
m2 4492 4692 197 >19.1
w2 4083 4282 197 >19.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.022 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 36134
Subject
GRB 240415A: Fermi GBM Observation
Date
2024-04-16T10:26:05Z (a year ago)
From
Cuán de Barra at UCD <cuan.debarra@ucdconnect.ie>
Via
Web form
C. de Barra (UCD) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
At 06:26:57.60 UT on 15 April 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240415A (trigger 734855222/240415269) which was also detected by Swift BAT (M.J. Moss et al. 2024, GCN 36108).
The Fermi GBM on-ground location (Fermi GBM Team, GCN 36107) is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 125.0 degrees
The GBM light curve contains a single emission episode with a duration (T90)
of about 10 s (50-300 keV). The time-averaged spectrum
from T0-4.1 to T0+6.1 s is best fit by is best fit by a Comptonized Epeak function with Epeak = 42.10 +/- 5.26 keV, and alpha = -1.58 +/- 0.14
The event fluence (10-1000 keV) in this time interval is (1.8 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.58 s in the 10-1000 keV band is 7.7 +/- 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 36132
Subject
GRB 240415A: Earliest optical followup with the Kinder observations
Date
2024-04-16T10:16:20Z (a year ago)
From
Amar Aryan <amararyan941@gmail.com>
Via
Web form
A. Aryan, T.-W. Chen, W.-J. Hou, H.-Y. Hsiao, C.-H. Lai, Y.-C. Pan (all NCUIA), S. Yang (HNAS), A. Sankar.K, M.-H. Lee, C.-S. Lin, C.-C. Ngeow, H.-C. Lin, J.-K. Guo (all NCUIA), H. F. Stevance, S. J. Smartt (Oxford/QUB), S. Srivastav (Oxford), M. Fulton, T. Moore, C. Angus, and A. Aamer (all QUB) report:
We observed the field of GRB 240415A (Fermi GBM team, GCN 36107; Moss et al., GCN 36108; Evans et al., GCN 36109) using the Lulin One-meter Telescope (LOT) at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen et al., AstroNote 2021-92). The optical afterglow candidate of GRB 240415A was identified (Pankov et al., GCN 36118, GCN 36121) and followed with several instruments (Lipunov et al., GCN 36119; Moskvitin et al., GCN 36122; Reguitti et al., GCN 36123, Schneider et al, GCN 36124).
The first LOT epoch of observations started at 13:17 UT on the 15th of April 2024. We followed the standard IRAF (Tody D., 1993, ASPC, 52, 173) procedure to reduce the images. Additionally, PSF photometry was performed using DAOPHOT II (Stetson P. B., 1987, PASP, 99, 191). The optical afterglow was clearly visible in the combined frame and was within the error box reported by Evans et al. (GCN 36128). The details of the observations and the preliminary magnitude (in the AB system) of the afterglow are as follows:
Telescope | Filter | MJD | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass
LOT | r | 60415.554 | 6.86 hrs | 300 sec * 6 | 21.32 +/- 0.25 | 1".92 | 1.67
The reported magnitude is calibrated using 10 nearby stars from the PanSTARRS catalog and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.02 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular 36128
Subject
GRB 240415A: Enhanced Swift-XRT position
Date
2024-04-16T00:23:15Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 822 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 240415A, 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 = 129.18882, +73.14634 which is equivalent
to:
RA (J2000): 08h 36m 45.32s
Dec (J2000): +73d 08' 46.8"
with an uncertainty of 2.8 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 36124
Subject
GRB 240415A: OHP/T193 optical observations
Date
2024-04-15T22:12:13Z (a year ago)
From
Benjamin Schneider at MIT <bschn@mit.edu>
Via
Web form
B. Schneider (MIT), C. Adami, O. Ilbert, N. A. Rakotondrainibe (LAM/Pytheas/AMU), D. Turpin, E. Le Floc’h (CEA Paris-Saclay), A. Saccardi, S. Vergani (GEPI/Obs. de Paris) report on behalf of a larger collaboration:
We observed the field of the GRB 240415A (Fermi GBM team, GCN 36107