GRB 220627A
GCN Circular 32454
Subject
GRB 220627A: MeerKAT radio observations
Date
2022-08-10T16:47:21Z (3 years ago)
From
Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>
S. Giarratana (U. Bologna, INAF/IRA), J. Leung (U. Sydney, CSIRO),
Z. Wang (U. Sydney, CSIRO), T. An (SHAO), A. Deller (Swinburne),
G. Ghirlanda (INAF/Brera), M. Giroletti (INAF/IRA), D. L. Kaplan (UWM),
E. Lenc (CSIRO), T. Murphy (U. Sydney), L. Rhodes (U. Oxford),
O. S. Salafia (U. Milano-Bicocca, INAF/Brera), C. Spingola (INAF/IRA)
The MeerKAT radio telescope observed GRB 220627A (Fermi GBM team, GCN
32278;
Frederiks et al., GCN 32295; Suresh et al., GCN 32316) at a central
frequency
of 1.28 GHz, with a bandwidth of 0.78 GHz, over two epochs, starting at
18:44 UT on 2022 July 6 (8.9 days post-burst) and at 13:43 UT on 2022
August 2
(35.7 days post-burst). Each observation lasted 2 hours.
From our preliminary analysis, no source is detected with a >3 sigma
significance at a position consistent with previous detections
(de Wet et al., GCN 32289; Izzo et al., GCN 32291; Gropp et al., GCN
32296;
Nicuesa Guelbenzu et al., GCN 32304; Leung et al., GCN 32341).
The rms noise is approximately 9 and 14 uJy/beam, in the first and
second
epoch, respectively.
Further observations are planned.
We would like to thank the MeerKAT personnel for approving, executing,
and processing these observations.
The MeerKAT telescope is operated by the South African Radio Astronomy
Observatory, which is a facility of the National Research Foundation,
an agency of the Department of Science and Innovation.
GCN Circular 32341
Subject
GRB 220627A: ATCA detection of radio counterpart
Date
2022-07-07T14:26:05Z (3 years ago)
From
James Leung at U of Sydney/VAST <jleu9465@uni.sydney.edu.au>
James Leung (U. Sydney, CSIRO), Ziteng Wang (U. Sydney, CSIRO), Tao
An (SHAO), Adam Deller (Swinburne), Giancarlo Ghirlanda (INAF/Brera),
Stefano Giarratana (U. Bologna, INAF/IRA), Marcello Giroletti
(INAF/IRA), David L. Kaplan (UWM), Emil Lenc (CSIRO), Tara Murphy
(U. Sydney), Lauren Rhodes (U. Oxford), Om Sharan Salafia
(U. Milano-Bicocca, INAF/Brera), Cristiana Spingola (INAF/IRA)
The Australia Telescope Compact Array (ATCA) observed GRB 220627A
(Fermi GBM team, GCN Circ. 32278) at multiple frequencies starting at
04:00 UT on 2022 July 5 (7.3 days post-burst). We detected a radio
source with a preliminary flux density of ~0.4 mJy at a central
frequency of 17 GHz at
RA = 13:25:28.48
Dec = -32:25:32.14
with positional uncertainty of ~1.5 arcsec. The position of the radio
source is consistent with the candidate optical (de Wet et al., GCN
Circ. 32289) and X-ray afterglow (Gropp et al., GCN Circ. 32296)
positions.
Further observations with several facilities at different frequencies
are ongoing.
We thank CSIRO staff for rapidly scheduling and supporting these
observations.
GCN Circular 32316
Subject
GRB 220627A: AstroSat CZTI detection
Date
2022-07-02T11:42:11Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
A. Suresh (IITB), G. Waratkar (IITB), R. Gopalakrishnan (IUCAA), V.
Prasad (IUCAA), 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 the long (or possibly
lensed) GRB 220627A which was also detected by Fermi GBM (Fermi GBM
team, GCN 32278; Roberts et al., GCN 32288), Fermi-LAT (Lalla et al.,
GCN 32283), Swift-BAT-GUANO (Raman et al., GCN 32287), Konus-Wind
(Frederiks et al., GCN 32295), and Swift-XRT (Gropp et al. GCN 32302).
AstroSat CZTI was in the South Atlantic Anomaly (SAA) region during the
first burst episode. About 1000s after the first burst, CZTI detected
the second burst episode that was also reported by Fermi-GBM (GCN
32288), and Konus-Wind (GCN 32295). This burst was clearly detected in
the 20-200 keV energy range. The light curve peaks at 2022-06-27
21:38:49.500 UTC. The measured peak count rate associated with the burst
is 233 (+43, -41) counts/s above the background in the combined data of
all four quadrants, with a total of 2707 (+454, -447) counts. The local
mean background count rate was 500 (+3, -4) counts/s. Using cumulative
rates, we measure a T90 of 43 (+2, -12) s.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb. 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.
GCN Circular 32304
Subject
GRB 220627A, GROND observations
Date
2022-06-30T15:07:56Z (3 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
A. Nicuesa Guelbenzu, S. Klose (both TLS Tautenburg), and A. Rau (MPE
Garching) report:
We observed the field of GRB 220627A (Fermi GBM team, GCN 32278) with
GROND mounted at the 2.2m MPG telescope at La Silla Observatory (Chile).
Observations started at 01:30 UT on June 30, 2022, about 2.2 days after
the GRB trigger and were on target for 20 minutes. They were performed at
an average seeing of 0.8 arcsec and at an airmass of 1.1.
The reported optical transient (de Wet et al., GCN 32289; Izzo et al., GCN
32291) is detected in the optical but not in the NIR bands with the
following (preliminary) magnitudes and upper limits (AB mags; 3 sigma):
g' = 23.31 +/- 0.11,
r' = 22.70 +/- 0.06,
i' = 22.50 +/- 0.12,
z' = 22.23 +/- 0.21,
J > 21.4,
H > 20.6,
K > 19.7.
The given limits are derived based on calibrating the optical images
against the SM catalog and the JHK data against 2MASS stars.
We thank Regis Lachaume and Paul Eigenthaler for excellent support and for
performing the observations.
GCN Circular 32302
Subject
GRB 220627A: Swift/UVOT Upper Limits
Date
2022-06-30T12:59:59Z (3 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M.H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220627A
130224 s after the LAT trigger (Di Lalla, et al., GCN Circ. 32283).
No optical afterglow consistent with the optical position (de Wet et al.,
GCN Circ. 32289, Izzo et al., GCN Circ. 33391) or X-ray afterglow
(Gropp et al., GCN Circ. 32296) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 130224 148828 4854 >22.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.047 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 32296
Subject
GRB 220627A: Swift-XRT afterglow detection
Date
2022-06-30T00:29:37Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J. D. Gropp (PSU), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J.A.
Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato
(INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 220627A (Di Lalla et al. GCN Circ. 32283),
collecting 4.9 ks of Photon Counting (PC) mode data between T0+44.3 ks
and T0+148.8 ks.
Fourteen uncatalogued X-ray sources are detected, of which one ("Source
3") is fading with >3-sigma significance, and is therefore likely the
GRB afterglow. Using 1679 s of PC mode data and 1 UVOT image, we find
an enhanced XRT position (using the XRT-UVOT alignment and matching
UVOT field sources to the USNO-B1 catalogue): RA, Dec = 201.36878,
-32.42624 which is equivalent to:
RA (J2000): 13h 25m 28.51s
Dec(J2000): -32d 25' 34.5"
with an uncertainty of 3.1 arcsec (radius, 90% confidence). This
position is 9.6 arcmin from the Fermi/LAT position and is consistent
with the previously detected candidate afterglow (GCN Circ 32289).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.4 (+0.8, -0.5).
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021506.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021506.
This circular is an official product of the Swift-XRT team.
GCN Circular 32295
Subject
Konus-Wind detection of GRB 220627A
Date
2022-06-29T17:44:21Z (3 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, A.Lysenko, A. Ridnaya, D. Svinkin, A. Tsvetkova,
M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The ultra-long (or possible lensed) GRB 220627A
(Fermi-GBM detection: Roberts et al., GCN 32288;
Fermi-LAT detection: Di Lalla et al., GCN 32283;
Swift/BAT-GUANO detection: Raman et al., GCN 32287)
was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian analysis of the burst light curve (lc) reveals
two separated, multi-peaked emission episodes.
The first episode starts at ~T0-140 s and ends at ~T0+290 s;
the second, weaker episode starts at ~T0+915 s and ends at ~T0+1150 s;
where T0 = T0(GBM) = 21:21:00 UT.
Although the described structure of the burst lc is consistent with that reported by GBM (GCN 32288),
a weak emission tail that can be traced in the KW soft energy band (~20-100 keV) till ~T0+3700 s.
We note that this extended emission is visible in the same KW detector,
i.e., it came from the same (southern) ecliptic hemisphere,
however its attribution to GRB 220627A cannot be unambiguously confirmed from the KW data alone.
The KW light curve of this burst is available
at http://www.ioffe.ru/LEA/GRBs/GRB220627A/
Modeling a time-integrated spectrum of the burst (measured from T0-140 s to T0+1150 s)
by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.23 (-0.14, + 0.19) and Ep = 250 (-49,+60) keV.
In the 10 keV -10 MeV band, standard for the KW analysis,
the total burst fluence is (1.07 �� 0.12)x10^-4 erg/cm^2
and the 2.944 s peak energy flux is (9.7 �� 0.7)x10^-7 erg/cm^2/s.
The spectrum of the first episode alone can be described by a CPL
with alpha = -0.85 (-0.09, + 0.09) and Ep = 324 (-19,+21) keV;
and the spectrum of the second, weaker episode - by a CPL
with alpha = -1.61 (-0.11, + 0.14) and Ep = 301 (-87,+233) keV.
From these fits, fluences in two individual episodes
are estimated to (7.2 �� 0.7)x10^-5 erg/cm^2 and (3.2 �� 1.2)x10^-5 erg/cm^2, respectively.
Assuming the redshift z=3.084 (Izzo et al., GCN 32291)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the burst isotropic energy release E_iso to (2.3 �� 0.3)x10^54 erg,
the isotropic peak luminosity L_iso on the (1+z)*64ms scale to (1.3 �� 0.1)x10^53 erg/s,
and the rest-frame peak energy of the time-integrated spectrum Ep,z to 1020(-200,+250) keV.
With the obtained estimates, GRB 220627A is inside 68% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs
with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB220627A/GRB220627A_rest_frame.pdf
GCN Circular 32291
Subject
GRB 220627A: VLT MUSE redshift
Date
2022-06-29T13:06:24Z (3 years ago)
From
Daniele B Malesani at Radboud U <d.malesani@astro.ru.nl>
L. Izzo (DARK/NBI), V. D'Elia (ASI/SSDC, INAF/OAR), A. de Ugarte Postigo
(OCA), J. P. U. Fynbo (DAWN/NBI), D. A. Kann (IAA-CSIC), A. J. Levan
(Radboud Univ.), D. B. Malesani (Radboud Univ. and DAWN/NBI), A.
Saccardi (GEPI/Paris Obs.), C. C. Thoene (ASU-CAS), J. F. Agui Fernandez
(IAA-CSIC), S. de Wet (UCT), P. J. Groot (Radboud Univ., UCT, SAAO),
report on behalf of the Stargate consortium:
We observed the candidate optical afterglow (de Wet et al., GCN 32289)
of the Fermi GBM and LAT GRB 220627A (Roberts et al., GCN 32288; Di
Lalla et al., GCN 32283) using the ESO VLT equipped with the MUSE
integral-field spectrograph. Observations were carried out starting on
2022 June 29.06 UT (1.17 days after the trigger), and cover the
wavelength range 4800-9300 AA.
A broad trough is detected centered around 4960 AA, which we interpret
as due to DLA HI absorption. A number of metal lines are also detected,
which we identify as, among others, O I, O I*, Si II, Si II*, C II, C
II*, Si IV, C IV, Al II, at a common redshift z = 3.084. We also note
the presence of a (rich) intervening system at z = 2.665 (as identified
by, e.g., S IV, Si II, C IV, Fe II, Al II).
The redshift and luminosity of this object, together with its X-ray
emission (Evans et al., GCN 32284), make it very likely to be the
afterglow of GRB 220627A. Using the preliminary GBM fluence and spectral
parameters (Roberts et al., GCN 32288), we derive an
isotropic-equivalent quasi-bolometric gamma-ray energy of 3.6*10^54 erg
(0.1 keV - 100 MeV rest frame).
We thank the ESO staff at Paranal for carrying out or observations, in
particular Jonathan Smoker, Camila Navarrete, Rodrigo Palominos, and
Marco Berton.
GCN Circular 32289
Subject
GRB 220627A: MeerLICHT candidate optical afterglow
Date
2022-06-28T22:59:47Z (3 years ago)
From
Simon de Wet at UCT <dwtsim002@myuct.ac.za>
S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO), D.B. Malesani (Radboud and
DAWN/NBI), A.J. Levan (Radboud) and D. Pieterse (Radboud) report on behalf
of the MeerLICHT consortium:
Following the Fermi/LAT detection and localisation of GRB 220627A (Di Lalla
et al., GCN 32283), also proposed to be a lensed or ultra-long GRB
candidate by Fermi/GBM (Roberts et al., GCN 32288), the 0.6 m wide-field
MeerLICHT optical telescope obtained 2x300s observations in the q-band of
two fields encompassing the LAT error box starting at 17:12:15 UT on 2022
June 28, approximately 1.17 days after the GBM trigger. We note that these
two fields were not observed during observations of the Fermi/GBM error box
from the previous night (Groot et al., GCN 32281). We also note that the
two transient candidates from those observations are not consistent with
the Fermi/LAT errorbox, therefore we exclude their association with GRB
220627A.
Within the error box of the uncatalogued X-ray Source 3 discovered by
Swift/XRT through ToO observations (Evans, GCN 32284), we detect a new
transient candidate at the following coordinates:
RA (J2000) = 13:25:28.49 (201.36872d)
Dec (J2000) = -32:25:33.31 (-32.42592d)
calibrated against Gaia DR2, with a positional uncertainty of 0.1" in each
coordinate. The same object is detected in a further 2x300s observations ~1
hour later. The source is detected with an AB magnitude of
q = 21.25 +/- 0.09
in the first exposure. We detect no source at the transient location in an
archival image of the same field down to a 3-sigma limiting magnitude of q
> 21.71. We suggest this may be the afterglow of GRB 220627A. Further
follow-up is encouraged.
MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester and the
University of Amsterdam.
GCN Circular 32288
Subject
GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
Date
2022-06-28T20:22:56Z (3 years ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
O.J. Roberts (USRA/NASA), B. Hristov (UAH) and C. Meegan (UAH) report
on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 21:21:00.09 UT on 27 June 2022, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 220627A (trigger 678057665/220627890)
which was also detected by the LAT (N. Di Lalla, et al. 2022, GCN 32283)
and observed by Swift-BAT-GUANO (G. Raman, et al. 2022, GCN 32287).
The Fermi GBM Final Real-time Localization (GCN 32278) is consistent
with the LAT position.
The angle from the Fermi LAT boresight is 27 degrees.
The GBM light curve shows multiple bursts over a duration (T90) of
about 138 s (10-1000 keV).
The time-averaged spectrum for the this burst from T0-5 s to T0+289 s
is best fit by a power law function with an exponential high-energy
cutoff. The power law index is -0.83 +/- 0.02 and the cutoff energy,
parameterized as Epeak, is 410 +/- 16 keV. The event fluence (10-1000 keV)
in this time interval is (7.88 +/- 0.13)E-05 erg/cm^2.
A Band function fits the spectrum equally well with Epeak= 390 +/- 20 keV,
alpha = -0.81 +/- 0.03 and beta = -2.68 +/- 0.31.
The 1-sec peak photon flux measured starting from T0+171.1 s in the
10-1000 keV band is 5.1 +/- 0.2 ph/s/cm^2.
Separately, about 1000 s later at 21:36:56.39 UT, GBM triggered on
678058621/220627901, which localized to a similar location of
RA: 207.02 deg. Dec: -28.48 deg. (J2000 degrees, equivalent to
J2000 13h 48m, +/- 28d 28'), with a statistical uncertainty of 1.2 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] ).
We find the T90 of this multiple pulsed burst of similar shape, to be
127 s (10-1000 keV). The time-averaged spectrum for the this burst
from T0-47 s to T0+122 s is best fit by a power law function with an
exponential high-energy cutoff. The power law index is -1.12 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 227 +/- 15 keV. The event
fluence (10-1000 keV) in this time interval is (2.47 +/- 0.08)E-05 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+113.2 s in the
10-1000 keV band is 3.5 +/- 0.2 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 32287
Subject
GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
Date
2022-06-28T19:37:07Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:
Swift/BAT did not localize GRB 220627A onboard (T0:
2022-06-27T21:21:00 UTC, Fermi/GBM GCN 32278, INTEGRAL trig #9970, ).
The INTEGRAL and Fermi/GBM notices, 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 90 seconds of BAT event-mode data from
[-45,+45] 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 31 in a 16.384
s analysis time bin.
NITRATES results indicate a burst coming from outside of the coded
FoV, with DeltaLLHOut of -70. The NITRATES maximum likelihood sky
position is consistent with the Fermi GBM and LAT localization region.
See Section 9.1 and Figure 20 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 32284
Subject
GRB 220627A: Swift ToO observations
Date
2022-06-28T09:37:08Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/LAT GRB 220627A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021506
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 32283
Subject
GRB 220627A: Fermi-LAT detection
Date
2022-06-28T07:00:40Z (3 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
N. Di Lalla (Stanford Univ.), M. Axelsson (KTH & Stockholm Univ.), M. Arimoto (Kanazawa Univ.), N. Omodei (Stanford Univ.) and M. Crnogor�evi� (Univ. of Maryland & NASA/GSFC) report on behalf of the Fermi-LAT team:
On June 27, 2022, Fermi-LAT detected high-energy emission from GRB 220627A, which was also detected by Fermi-GBM (trigger 678057665 / 220627890, GCN 32278).
The best LAT on-ground location is found to be
RA, Dec = 201.2, -32.5 (degrees, J2000)
with an error radius of 0.2 deg (90 % containment, statistical error only). This was 27 deg from the LAT boresight at the time of the GBM trigger:
T0 = 21:21:00.9 UT.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The 100 MeV - 1 GeV photon flux in the time interval 0-600 s after the GBM trigger is (1.8 +/- 0.3)E-05 ph/cm2/s, and the photon flux above 1 GeV is (1.3 +/- 0.4)E-06 ph/cm2/s. The estimated photon index above 100 MeV is -2.2 +/- 0.15. The highest-energy photon is a 15.7 GeV event which is observed 176 seconds after the GBM trigger.
A Swift ToO has been requested for this burst.
The Fermi-LAT point of contact for this burst is Milena Crnogor�evi� (mcrnogor@astro.umd.edu<mailto:mcrnogor@astro.umd.edu>).
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 32281
Subject
GRB 220627A: MeerLICHT detection of two afterglow candidates
Date
2022-06-28T02:12:29Z (3 years ago)
From
Paul Groot at Radboud University Nijmegen <p.groot@astro.ru.nl>
P.J. Groot (Radboud/UCT/SAAO), S. de Wet (UCT/SAAO), P.M. Vreeswijk
(Radboud) report on behalf of the MeerLICHT consortium:
Following the detection of GRB220627A by Fermi (Fermi GBM team, GCN
32278) the MeerLICHT 0.6m wide-field optical telescope, located at
SAAO Sutherland, South Africa, started scanning the error box at
2022-06-27 21:43 UT (T0+23 minutes and 3 minutes after the alert was
received). Observations were obtained in the q-band (440-720nm), using
52 tiles (146 square degrees) to cover a 71% cumulative
probabilty. Before the observability limit of HA=+4.5 hr was reached
32.4 square degrees were covered at least twice, covering a cumulative
probability of 7.5% of the Fermi error box.
Automatic data processing using BlackBOX/ZOGY resulted in 7 new
transients that were observed at least twice and were detected with a
significance >12 in the difference images. Five of these candidates
can be associated to known asteroids.
The remaining two candidates are uncataloged and are both detected
three times:
Candidate 1 is MLTJ143615.50-360417.3,
at RA,Dec (ICRS) 14:36:15.50, -36:04:17.3 (219.06459,-36.07149),
first detected at q_AB = 18.13+/-0.03 on 2022-06-27 22:50:22/05 (MJD
59757.95164). Last non-detection was on MJD 58971.02.19 at q_AB > 20.35
(for a transient source).
Candidate 2 is MLTJ143614.90-373629.0,
at RA,Dec (ICRS) 14:36:14.90. -37:36:29.0 (219.06217,-37.60809),
first detected at q_AB = 19.62+/-0.10, on 2022-06-27 22:53:20.54 (MJD
59757.95371). Last non-detection was on MJD 59737.8835 at q_AB > 20.82
Candidate 1 shows the presence of an underlying object in the MeerLICHT
reference image at q_AB = 20.72, possibly a host galaxy.
Candidate 2 shows no underlying source in the MeerLICHT reference image
with a limiting magnitude of q_AB > 20.28.
During the three MeerLICHT observations Candidate 1 evolved to q_AB =
18.21 +/-0.02 at 2022-06-27 23:16:51 (MJD 59757.97004). Candidate 2
brightened to q_AB = 19.43 +/- 0.10 at 2022-06-27 23:18:14 (MJD
59757.97100).
Follow-up observations of both candidates are encouraged.
MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester and
the University of Amsterdam.
GCN Circular 32280
Subject
Fermi GRB 220627A: Global MASTER-Net observations report
Date
2022-06-27T22:00:31Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(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. Gres, N.M. Budnev
(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),
A. Gabovich, V.Yurkov
(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 220627A ( Fermi GBM team, GCN 32278) errorbox 579 sec after notice time and 592 sec after trigger time at 2022-06-27 21:30:52 UT, with upper limit up to 19.9 mag. The observations began at zenith distance = 39 deg. The sun altitude is -72.1 deg.
The galactic latitude b = 25 deg., longitude l = 320 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2016919
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
653 | 2022-06-27 21:30:52 | MASTER-SAAO | (14h 04m 14.66s , -35d 01m 06.7s) | C | 120 | 19.9 |
802 | 2022-06-27 21:33:12 | MASTER-SAAO | (14h 04m 12.35s , -34d 59m 11.6s) | C | 140 | 19.9 |
1231 | 2022-06-27 21:41:01 | MASTER-SAAO | (14h 06m 01.84s , -34d 45m 29.2s) | C | 60 | 19.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 32278
Subject
GRB 220627A: Fermi GBM Final Real-time Localization
Date
2022-06-27T21:31:11Z (3 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 21:21:00 UT on 27 Jun 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220627A (trigger 678057665.085772 / 220627890).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 211.5, Dec = -35.1 (J2000 degrees, equivalent to J2000 14h 05m, -35d 06'), with a statistical uncertainty of 4.2 degrees.
The angle from the Fermi LAT boresight is 20.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220627890/quicklook/glg_skymap_all_bn220627890.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220627890/quicklook/glg_healpix_all_bn220627890.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220627890/quicklook/glg_lc_medres34_bn220627890.gif