GRB 240527B
GCN Circular 36545
Subject
GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
Date
2024-05-27T14:42:34Z (a year ago)
From
Jochen Greiner at MPE <jcgrog@mpe.mpg.de>
Via
email
T. Preis, B. Biltzinger, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
738511436 at 14:03:51 on 27 May 2024 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
RA(2000.0) = 128.0 deg
Decl.(2000.0) = -15.2 deg
The 1 sigma statistical error radius is 3.4 deg.
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240527586/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240527586/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240527586/json
GCN Circular 36546
Subject
GRB 240527B: Fermi GBM Final Localization
Date
2024-05-27T15:08:45Z (a year ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
Via
Web form
The Fermi GBM team reports the detection of a likely LONG GRB
"At 14:03:51.50 UT on 27 May 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240527B (trigger 738511436/240527586).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 128.51, Dec = -12.68 (J2000 degrees, equivalent to J2000 8h 34m, -12d 40'),
with a statistical uncertainty of 1.70 degrees.
The angle from the Fermi LAT boresight is 78 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240527586/quicklook/glg_skymap_all_bn240527586.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240527586/quicklook/glg_healpix_all_bn240527586.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240527586/quicklook/glg_lc_medres34_bn240527586.gif"
GCN Circular 36547
Subject
Fermi GRB 240527B: Global MASTER-Net observations report
Date
2024-05-27T17:15:55Z (a year 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240527B ( Fermi GBM team, GCN 36546) errorbox 9266 sec after notice time and 9291 sec after trigger time at 2024-05-27 16:38:42 UT, with upper limit up to 19.4 mag. Observations started at twilight. The observations began at zenith distance = 33 deg. The sun altitude is -11.7 deg.
The galactic latitude b = 16 deg., longitude l = 237 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2472451
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
9321 | 2024-05-27 16:38:42 | MASTER-SAAO | (08h 28m 27.08s , -12d 11m 25.9s) | C | 60 | 18.5 |
9401 | 2024-05-27 16:40:02 | MASTER-SAAO | (08h 36m 37.47s , -12d 10m 23.3s) | C | 60 | 18.6 |
10243 | 2024-05-27 16:54:04 | MASTER-SAAO | (08h 28m 28.80s , -12d 10m 06.2s) | C | 60 | 19.1 |
10323 | 2024-05-27 16:55:24 | MASTER-SAAO | (08h 36m 36.04s , -12d 10m 49.2s) | C | 60 | 19.3 |
10403 | 2024-05-27 16:56:44 | MASTER-SAAO | (08h 32m 25.70s , -14d 04m 43.2s) | C | 60 | 19.2 |
10483 | 2024-05-27 16:58:04 | MASTER-SAAO | (08h 40m 34.75s , -14d 05m 43.1s) | C | 60 | 19.2 |
10563 | 2024-05-27 16:59:24 | MASTER-SAAO | (08h 25m 05.25s , -10d 15m 57.2s) | C | 60 | 19.2 |
10642 | 2024-05-27 17:00:43 | MASTER-SAAO | (08h 33m 14.26s , -10d 17m 11.8s) | C | 60 | 19.3 |
10803 | 2024-05-27 17:03:24 | MASTER-SAAO | (08h 24m 52.36s , -14d 03m 20.3s) | C | 60 | 19.2 |
10883 | 2024-05-27 17:04:44 | MASTER-SAAO | (08h 43m 57.14s , -12d 11m 27.0s) | C | 60 | 19.3 |
11042 | 2024-05-27 17:07:23 | MASTER-SAAO | (08h 40m 33.16s , -10d 16m 51.0s) | C | 60 | 19.4 |
11202 | 2024-05-27 17:10:03 | MASTER-SAAO | (08h 28m 19.16s , -12d 10m 06.0s) | C | 60 | 19.3 |
11282 | 2024-05-27 17:11:23 | MASTER-SAAO | (08h 36m 32.47s , -12d 09m 07.5s) | C | 60 | 19.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 36550
Subject
GRB 240527B: Fermi-LAT detection
Date
2024-05-27T23:09:39Z (a year ago)
From
Rahul Gupta at NASA/GSFC <rahulbhu.c157@gmail.com>
Via
email
R. Gupta (NASA/GSFC), F. Longo (University and INFN, Trieste), and A.
Holzmann (DF, University of Buenos Aires, Argentina) report on behalf of
the Fermi-LAT Collaboration:
At 14:03:51.50 on May, 27, 2024 Fermi-LAT detected high-energy emission
from GRB 240527B which was also detected by Fermi-GBM (trigger 738511436 /
240527586, GCN 36546).
The best LAT on-ground location is found to be
RA, Dec = 128.10, -14.48 (J2000)
with an error radius of 0.19 deg (90 % containment, statistical error only).
This was 77 deg from the LAT boresight at the time of the trigger.
The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the trigger with high
significance. The photon flux above 100 MeV in the time interval 0-3000 s
after the GBM trigger is (6.2 +/- 3.0) E-7 ph/cm2/s. The estimated photon
index above 100 MeV is - 1.6+/- 0.2.
The highest-energy photon is a 4.0 GeV event which is observed about
1200 seconds after the GBM trigger.
A Swift ToO has been approved.
The Fermi-LAT point of contact for this burst is Rahul Gupta (
rahul.gupta@nasa.gov).
The Fermi-LAT is a pair conversion telescope designed to cover the energy
band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
GCN Circular 36553
Subject
GRB 240527B: Fermi GBM Observation
Date
2024-05-28T03:01:00Z (a year 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 Gamma-ray Burst Monitor Team:
"At 14:03:51.50 UT on 27 May 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240527B (trigger 738511436/240527586).
which was also detected by Fermi LAT (R. Gupta et al. 2024, GCN 36550).
The Fermi GBM on-ground location (GCN 36546) is consistent with the Fermi LAT position.
The angle from the Fermi LAT boresight is 78 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 24.8 s (50-300 keV). The time-averaged spectrum
from T0+0.003 to T0+29.440 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.07 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 280 +/- 20 keV.
The event fluence (10-1000 keV) in this time interval is
(1.46 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+14 s in the 10-1000 keV band is 10.9 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 201 +/- 20 keV, alpha = -0.95 +/- 0.05 and beta = -2.1 +/- 0.1.
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/"C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 14:03:51.50 UT on 27 May 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240527B (trigger 738511436/240527586).
which was also detected by Fermi LAT (R. Gupta et al. 2024, GCN 36550).
The Fermi GBM on-ground location (GCN 36546) is consistent with the Fermi LAT position.
The angle from the Fermi LAT boresight is 78 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 24.8 s (50-300 keV). The time-averaged spectrum
from T0+0.003 to T0+29.440 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.07 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 280 +/- 20 keV.
The event fluence (10-1000 keV) in this time interval is
(1.46 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+14 s in the 10-1000 keV band is 10.9 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 201 +/- 20 keV, alpha = -0.95 +/- 0.05 and beta = -2.1 +/- 0.1.
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 36558
Subject
GRB 240527B: Swift-XRT afterglow detection
Date
2024-05-29T05:53:44Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
J. D. Gropp (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato
(INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 240527B, collecting 5.2 ks of Photon
Counting (PC) mode data between T0+27.3 ks and T0+135.5 ks.
Eight uncatalogued X-ray sources are detected, of which one ("Source
7") is above the RASS 3-sigma upper limit at this position and fading
with >3-sigma significance, and is therefore likely the GRB afterglow.
Using 1624 s of PC mode data and 3 UVOT images, we find an enhanced XRT
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 128.15387, -14.43738 which is
equivalent to:
RA (J2000): 08h 32m 36.93s
Dec(J2000): -14d 26' 14.6"
with an uncertainty of 2.0 arcsec (radius, 90% confidence). This
position is 4.0 arcmin from the Fermi/LAT position.
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.23 (+0.16, -0.14).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.70 (+0.08, -0.06). The
best-fitting absorption column is consistent with the Galactic value
of 5.7 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 3.8 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 5.7 (+/-1.9) x 10^20 cm^-2
Galactic foreground: 5.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.70 (+0.08, -0.06)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021694.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021694.
This circular is an official product of the Swift-XRT team.