GRB 240720A
GCN Circular 36909
Subject
GRB 240720A: Swift detection of a burst
Date
2024-07-20T00:40:15Z (10 months ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
R. Gupta (NASA/GSFC), V. D'Elia (SSDC & INAF-OAR) and
D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 00:24:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240720A (trigger=1243868). Swift did not slew to the burst
due to a pointing constraint.
The BAT on-board calculated location is
RA, Dec 96.700, +30.342 which is
RA(J2000) = 06h 26m 48s
Dec(J2000) = +30d 20' 30"
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 3 sec. The peak count rate
was ~5400 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT
position. There will thus be no immediate XRT or UVOT data for
this trigger.
Burst Advocate for this burst is R. Gupta (rahulbhu.c157 AT gmail.com).
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 36910
Subject
GRB 240720A: Fermi GBM observation
Date
2024-07-20T16:27:50Z (10 months ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
Via
Web form
C. Fletcher (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 00:24:51.22 UT on 20 July 2024, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 240720A (trigger 743127896 / 240720017),
which was also detected by the Swift/BAT (Gupta et al. 2024, GCN 36909) and INTEGRAL SPI/ACS (trigger 10797).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 47 degrees.
The GBM light curve consists of multiple peaks
with a duration (T90) of about 1.8 s (50-300 keV).
The time-averaged spectrum from T0+0.002 s to T0+2.176 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.66 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 1069 +/- 172 keV.
The event fluence (10-1000 keV) in this time interval is
(3.9 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.896 s in the 10-1000 keV band
is 9.1 +/- 1.0 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 36911
Subject
GRB 240720A: AstroSat CZTI detection
Date
2024-07-20T17:11:10Z (10 months ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
J. Joshi (IUCAA), A. Dasgupta (BITS Pilani, Hyderabad), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of GRB 240720A which was also detected by Swift/BAT (Gupta et al., GCN Circ. 36909), Fermi/GBM (Fletcher et al., GCN Circ. 36910), and INTEGRAL/SPI-ACS (Trigger 10797).
The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-07-20 00:24:52.25 UTC. The measured peak count rate associated with the burst is 121 (+42, -36) counts/s above the background in the combined data of three quadrants (out of four), with a total of 212 (+72, -75) counts. The local mean background count rate was 226 (+5, -6) counts/s. Using cumulative rates, we measure a T90 of 2.7 (+0.9, -1.1) s.
The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-07-20 00:24:51.63 UTC. The measured peak count rate associated with the burst is 381 (+66, -71) counts/s above the background in the combined data of all quadrants, with a total of 598 (+150, -160) counts. The local mean background count rate was 1281 (+8, -8) counts/s. We measure a T90 of 2.2 (+0.3, -0.9) s from the cumulative Veto light curve.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 36912
Subject
Fermi GRB 240720A: Global MASTER-Net observations report
Date
2024-07-21T02:15:55Z (10 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 240720A ( C. Fletcher et al., GCN 36910) errorbox 85623 sec after notice time and 85662 sec after trigger time at 2024-07-21 00:12:33 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 77 deg. The sun altitude is -17.6 deg.
The galactic latitude b = 16 deg., longitude l = 174 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2535620
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
85692 | 2024-07-21 00:12:33 | MASTER-Tavrida | (06h 23m 51.35s , +44d 06m 28.9s) | C | 60 | 16.4 |
85692 | 2024-07-21 00:12:33 | MASTER-Tavrida | (06h 23m 44.17s , +44d 11m 29.8s) | C | 60 | 12.9 |
85844 | 2024-07-21 00:15:04 | MASTER-Tavrida | (06h 15m 41.27s , +42d 46m 42.4s) | C | 60 | 16.6 |
85844 | 2024-07-21 00:15:05 | MASTER-Tavrida | (06h 15m 34.35s , +42d 51m 42.1s) | C | 60 | 15.9 |
85919 | 2024-07-21 00:16:20 | MASTER-Tavrida | (06h 32m 34.56s , +45d 24m 21.2s) | C | 60 | 16.5 |
85919 | 2024-07-21 00:16:20 | MASTER-Tavrida | (06h 32m 27.40s , +45d 29m 21.2s) | C | 60 | 14.9 |
87055 | 2024-07-21 00:35:15 | MASTER-Tavrida | (06h 23m 44.72s , +44d 05m 43.9s) | C | 60 | 16.5 |
87055 | 2024-07-21 00:35:16 | MASTER-Tavrida | (06h 23m 38.07s , +44d 10m 39.2s) | C | 60 | 17.0 |
87130 | 2024-07-21 00:36:31 | MASTER-Tavrida | (06h 34m 59.60s , +44d 05m 29.5s) | C | 60 | 16.4 |
87130 | 2024-07-21 00:36:31 | MASTER-Tavrida | (06h 34m 52.78s , +44d 10m 26.1s) | C | 60 | 16.9 |
87206 | 2024-07-21 00:37:47 | MASTER-Tavrida | (06h 15m 38.08s , +42d 44m 56.7s) | C | 60 | 17.0 |
87206 | 2024-07-21 00:37:47 | MASTER-Tavrida | (06h 15m 31.46s , +42d 49m 53.4s) | C | 60 | 17.5 |
87282 | 2024-07-21 00:39:02 | MASTER-Tavrida | (06h 26m 37.68s , +42d 45m 52.5s) | C | 60 | 16.5 |
87282 | 2024-07-21 00:39:02 | MASTER-Tavrida | (06h 26m 30.91s , +42d 50m 49.4s) | C | 60 | 17.1 |
87357 | 2024-07-21 00:40:18 | MASTER-Tavrida | (06h 32m 28.36s , +45d 24m 08.5s) | C | 60 | 16.8 |
87357 | 2024-07-21 00:40:18 | MASTER-Tavrida | (06h 32m 21.42s , +45d 29m 05.2s) | C | 60 | 17.2 |
87433 | 2024-07-21 00:41:33 | MASTER-Tavrida | (06h 43m 51.42s , +45d 23m 16.1s) | C | 60 | 16.7 |
87433 | 2024-07-21 00:41:33 | MASTER-Tavrida | (06h 43m 44.36s , +45d 28m 13.4s) | C | 60 | 17.0 |
87583 | 2024-07-21 00:44:04 | MASTER-Tavrida | (06h 18m 41.97s , +41d 27m 51.9s) | C | 60 | 16.7 |
87584 | 2024-07-21 00:44:04 | MASTER-Tavrida | (06h 18m 35.37s , +41d 32m 49.1s) | C | 60 | 17.1 |
87734 | 2024-07-21 00:46:34 | MASTER-Tavrida | (06h 29m 05.41s , +45d 22m 38.0s) | C | 60 | 16.6 |
87734 | 2024-07-21 00:46:34 | MASTER-Tavrida | (06h 28m 58.60s , +45d 27m 34.8s) | C | 60 | 17.2 |
87885 | 2024-07-21 00:49:06 | MASTER-Tavrida | (06h 20m 29.41s , +44d 03m 06.4s) | C | 60 | 16.7 |
87885 | 2024-07-21 00:49:06 | MASTER-Tavrida | (06h 20m 22.82s , +44d 08m 02.5s) | C | 60 | 17.1 |
88262 | 2024-07-21 00:55:23 | MASTER-Tavrida | (06h 23m 42.82s , +44d 04m 55.1s) | C | 60 | 16.5 |
88262 | 2024-07-21 00:55:23 | MASTER-Tavrida | (06h 23m 36.27s , +44d 09m 51.5s) | C | 60 | 17.0 |
88337 | 2024-07-21 00:56:38 | MASTER-Tavrida | (06h 34m 55.98s , +44d 04m 39.2s) | C | 60 | 16.4 |
88337 | 2024-07-21 00:56:38 | MASTER-Tavrida | (06h 34m 49.31s , +44d 09m 35.9s) | C | 60 | 16.9 |
88414 | 2024-07-21 00:57:55 | MASTER-Tavrida | (06h 15m 34.44s , +42d 44m 18.1s) | C | 60 | 16.7 |
88414 | 2024-07-21 00:57:55 | MASTER-Tavrida | (06h 15m 28.08s , +42d 49m 14.2s) | C | 60 | 17.0 |
88489 | 2024-07-21 00:59:10 | MASTER-Tavrida | (06h 26m 35.20s , +42d 45m 09.6s) | C | 60 | 16.3 |
88489 | 2024-07-21 00:59:10 | MASTER-Tavrida | (06h 26m 28.72s , +42d 50m 05.7s) | C | 60 | 16.8 |
88564 | 2024-07-21 01:00:25 | MASTER-Tavrida | (06h 32m 25.26s , +45d 23m 00.1s) | C | 60 | 16.4 |
88564 | 2024-07-21 01:00:25 | MASTER-Tavrida | (06h 32m 18.62s , +45d 27m 56.1s) | C | 60 | 16.8 |
88645 | 2024-07-21 01:01:46 | MASTER-Tavrida | (06h 43m 48.35s , +45d 22m 28.2s) | C | 60 | 16.2 |
88646 | 2024-07-21 01:01:46 | MASTER-Tavrida | (06h 43m 41.55s , +45d 27m 24.6s) | C | 60 | 16.7 |
88797 | 2024-07-21 01:04:18 | MASTER-Tavrida | (06h 18m 39.42s , +41d 27m 20.1s) | C | 60 | 16.2 |
88797 | 2024-07-21 01:04:18 | MASTER-Tavrida | (06h 18m 33.15s , +41d 32m 16.0s) | C | 60 | 16.6 |
88947 | 2024-07-21 01:06:48 | MASTER-Tavrida | (06h 29m 01.38s , +45d 21m 52.7s) | C | 60 | 16.1 |
88947 | 2024-07-21 01:06:48 | MASTER-Tavrida | (06h 28m 54.99s , +45d 26m 47.6s) | C | 60 | 16.5 |
89097 | 2024-07-21 01:09:18 | MASTER-Tavrida | (06h 20m 26.32s , +44d 02m 29.3s) | C | 60 | 15.9 |
89097 | 2024-07-21 01:09:18 | MASTER-Tavrida | (06h 20m 20.12s , +44d 07m 23.6s) | C | 60 | 16.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 36928
Subject
GRB 240720A: Swift-BAT refined analysis
Date
2024-07-23T20:52:12Z (10 months ago)
From
Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>
Via
email
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
R. Gupta (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), M. J. Moss (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC),
D. Sadaula (GSFC/UMBC)(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240720A (trigger #1243868)
(Gupta, et al., GCN Circ. 36909). The BAT ground-calculated position is
RA, Dec = 96.728, 30.297 deg which is
RA(J2000) = 06h 26m 54.6s
Dec(J2000) = +30d 17' 48.3"
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.
The mask-weighted BAT light curve shows a short hard spike, followed by an extended softer emission with a duration of ~ 200 sec. T90 (15-350 keV) is 181.85 +- 73.84 sec (estimated error including systematics).
The time-averaged spectrum from T-0.12 to T+193.92 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.47 +- 0.22. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+0.44 sec in the 15-150 keV band is 2.5 +- 0.3 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/1243868