GRB 240619A
GCN Circular 36694
Subject
GRB 240619A: Fermi GBM Final Real-time Localization
Date
2024-06-19T03:54:00Z (a year ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 03:43:31 UT on 19 Jun 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240619A (trigger 740461416.003318 / 240619155).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 162.1, Dec = 17.3 (J2000 degrees, equivalent to J2000 10h 48m, 17d 18'), with a statistical uncertainty of 1.6 degrees.
The angle from the Fermi LAT boresight is 63.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240619155/quicklook/glg_skymap_all_bn240619155.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/bn240619155/quicklook/glg_healpix_all_bn240619155.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240619155/quicklook/glg_lc_medres34_bn240619155.gif
GCN Circular 36695
Subject
GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
Date
2024-06-19T04:41:44Z (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
740461416 at 03:43:31 on 19 June 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) = 162.2 deg
Decl.(2000.0) = 14.8 deg
The 1 sigma statistical error radius is 3.2 deg.
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240619155/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240619155/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240619155/json
GCN Circular 36708
Subject
Fermi GRB 240619A: Global MASTER-Net observations report
Date
2024-06-19T23:45:42Z (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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 240619A ( Fermi GBM team, GCN 36694) errorbox 55438 sec after notice time and 55481 sec after trigger time at 2024-06-19 19:08:12 UT, with upper limit up to 16.7 mag. The observations began at zenith distance = 68 deg. The sun altitude is -17.7 deg.
The galactic latitude b = 60 deg., longitude l = 227 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2499301
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
55512 | 2024-06-19 19:08:12 | MASTER-Kislovodsk | (10h 49m 58.96s , +16d 22m 16.8s) | C | 60 | 16.7 |
57629 | 2024-06-19 19:43:30 | MASTER-Kislovodsk | (10h 43m 55.90s , +14d 27m 58.5s) | C | 60 | 16.3 |
57710 | 2024-06-19 19:44:50 | MASTER-Kislovodsk | (10h 44m 03.04s , +14d 26m 52.8s) | C | 60 | 16.1 |
58111 | 2024-06-19 19:51:32 | MASTER-Kislovodsk | (10h 49m 57.47s , +16d 21m 38.9s) | C | 60 | 15.9 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 36715
Subject
GRB 240619A: GOTO candidate optical afterglow
Date
2024-06-20T21:07:53Z (a year ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
Via
email
B. P. Gompertz, K. Ackley, S. Belkin, T. Killestein, A. J. Levan, B. Godson, R. Starling, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, A. Kumar, D. O'Neill, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 240619A (Fermi GBM Team, GCN 36694). Targeted observations were performed by GOTO-South at 08:21:34 UT on 2024-06-19 (3x90s exposures, 4.7 hours after trigger), and by GOTO-North at 21:40:50 UT on 2024-06-19 (4x90s exposures, 18.0 hours after trigger). Observations were taken in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.
A new optical source AT 2024lwv<https://www.wis-tns.org/object/2024lwv> (GOTO24cvn) is identified within the GBM 90% localisation region at RA = 10:49:34.70, Dec = +17:16:58.07 with an initial magnitude of L = 17.17 +/- 0.17 mags 4.7 hours after trigger, fading to L = 18.38 +/- 0.09 mags at 18.0 hours after trigger. The source is also present in the data available on the ATLAS forced photometry server (Shingles et al. 2021) with an initial magnitude of o = 16.2 +/- 0.04, 2.3 hours after the GRB trigger. Observations are consistent with a power-law decay of approximately t^-0.8. The transient was not detected in the most recent pre-trigger GOTO observation, taken at 21:54:02 UT on 2024-06-17 (~1.25 days prior to the GRB) to a 5-sigma limiting magnitude of L > 19.2 mags.
The transient is spatially coincident (0.1” offset) with the catalogued galaxy PSO J162.3946+17.2828 with a photometric redshift of 0.63 +/- 0.19 in the PS1-STRM catalogue (Beck et al. 2020). Due to the galaxy association, rapid decay, and lack of detection in pre-GRB imaging, we propose this source as the optical afterglow of GRB 240619A.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
Observations are ongoing.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 36717
Subject
GRB 240619A: Fermi GBM Observation
Date
2024-06-21T01:21:00Z (a year ago)
Edited On
2024-06-21T02:07:39Z (a year ago)
From
Sarah Dalessi at UAH <sd0104@uah.edu>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Sarah Dalessi at UAH <sd0104@uah.edu>
Via
Web form
S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 03:43:31.00 UT on 19 June 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240619A (trigger 740461416/240619155), which was also
detected by the Gravitational-wave Optical Transient Observer (GOTO) (Gompertz et al. 2024, GCN 36715).
The Fermi-GBM Final Real-time location (Fermi GBM Team 2024, GCN 36694)
is consistent with the GOTO position.
The angle from the Fermi LAT boresight is 63 degrees.
The GBM light curve two emission episodes with a duration (T90)
of about 36.1 s (50-300 keV). The time-averaged spectrum
from T0+0.002 to T0+36.129 s is best fit by
a Band function with Epeak = 110 +/- 50 keV,
alpha = -1.3 +/- 0.2, and beta = -1.70 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(1.19 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.096 s in the 10-1000 keV band is 19.1 +/- 0.4 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 36719
Subject
GRB 240619A: CALET Gamma-Ray Burst Monitor detection
Date
2024-06-21T07:03:46Z (a year ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
S. Torii (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR),
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 240619A (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 36694; BALROG localization: Preis et al., GCN Circ. 36695; Fermi GBM
Observation: Dalessi et al., GCN Circ. 36717) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 03:43:30.40 UTC on 19 June 2024
(https://cgbm.calet.jp/cgbm_trigger/flight/1402803348/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked structure that starts
at T+0.6 sec, peaks at T+1.1 sec, and ends at T+37.4 sec.
The T90 and T50 durations measured by the SGM data are 35.0 +/- 1.3 sec
and 28.5 +/- 1.1 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1402803348/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 36720
Subject
GRB 240619A: Swift ToO observations
Date
2024-06-21T07:31:35Z (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 team:
Swift has initiated a ToO observation of the Fermi/GBM GRB 240619A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021697
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/GBM 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 36721
Subject
GRB 240619A: Swift-XRT probable afterglow detection
Date
2024-06-21T08:07:00Z (a year ago)
Edited On
2024-06-21T13:52:56Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of P.A. Evans at U. Leicester <pae9@leicester.ac.uk>
Via
email
M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC &
INAF-OAR), S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U.
Toronto), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester)
and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 240619A (GCN Circ. 36694), collecting 1.7
ks of Photon Counting (PC) mode data between T0+174.0 ks and T0+175.7
ks at the location of the GOTO afterglow candidate AT 2024lwv (Gompertz
et al., GCN Circ. 36715).
An uncatalogued X-ray source is detected at RA, Dec=162.3944, +17.2829
which is equivalent to:
RA (J2000): 10:49:34.66
Dec(J2000): +17:16:58.5
with an uncertainty of 4.3 arcsec (radius, 90% confidence). This
position is 0.7 arcsec from the GOTO position and thus we suggest it is
related to that object and likely the GRB afterglow. The source has a
mean count rate of 2.5e-02 ct/sec; we cannot determine at the present
time whether it is fading.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021697.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021697.
This circular is an official product of the Swift-XRT team.
GCN Circular 36724
Subject
GRB 240619A: GRBAlpha detection
Date
2024-06-21T14:40:54Z (a year ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 240619A (Fermi/GBM detection: GCN 36694; CALET/CGBM detection: GCN 36719; INTEGRAL/SPI-ACS peak detection at 2024-06-19 ~03:43:31 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2024-06-19 03:43:30.7 UTC. The T90 duration measured by GRBAlpha is 4.5 s and the overall significance during T90 reaches 10 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240619A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 36739
Subject
GRB 240619A: J-band detection with WINTER
Date
2024-06-23T01:24:30Z (a year ago)
From
Geoffrey Mo at MIT <gmo@mit.edu>
Via
Web form
Geoffrey Mo (MIT), Robert Stein (Caltech), Benjamin Schneider (MIT), Viraj Karambelkar (Caltech), Danielle Frostig (MIT), Nathan Lourie (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:
We observed the field of GRB 240619A (Fermi GBM team, GCN 36694; Greiner et al., GCN 36695; Dalessi et al., GCN 36717; Torii et al., GCN 36719; Dafcikova et al., GCN 36724) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020).
Observations began at 2024-06-21T03:44:09 UTC (~48 hours after the GRB) and consisted of 30 x 120 s exposures. The images were processed using the WINTER data reduction pipeline (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.10888436), with image subtraction performed relative to J-band images from the UKIRT Hemisphere survey (Dye et al., 2017).
We report the marginal (3-sigma) detection of a source at the position of the GOTO-discovered counterpart (Gompertz et al., GCN 36715; Lipunov et al., GCN 36708; Evans et al., GCN 36720; Capalbi et al., GCN 36721), with magnitude J ~ 19.3 (AB).
WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
GCN Circular 36740
Subject
GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
Date
2024-06-23T01:24:00Z (a year ago)
Edited On
2024-06-23T01:31:08Z (a year ago)
From
Geoffrey Mo at MIT <gmo@mit.edu>
Edited By
Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Via
Web form
This was a duplicate submission of GCN 36739.
GCN Circular 36744
Subject
GRB 240619A: detection of a radio counterpart with AMI-LA
Date
2024-06-24T10:36:50Z (a year ago)
From
Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk>
Via
Web form
Lauren Rhodes, Rob Fender (Oxford), Dave Green, Dave Titterington (Cambridge) report:
We observed the field of GRB 240619a (GCN 36694) with the Arcminute Microkelvin Imager - Large Array (AMI-LA) at 15.5 GHz beginning at UT 13:45:34 on 22-June-2024 for a total of 4 hours. The flux standard 3c286 was used to calibrate the bandpass response and flux scale of the AMI-LA and J1051+2119 was used as an interleaved complex gain calibrator.
We detected an unresolved radio source at the position of the afterglow candidate (GCN 36715) with a flux density of about 1.5mJy/beam. The rms noise in the field is about 60uJy/beam.
More observations are ongoing.
We thank the staff at the Mullard Radio Astronomy Observatory for carrying out these observations and operating the AMI-LA.
GCN Circular 36768
Subject
Konus-Wind detection of GRB 240619A
Date
2024-06-26T21:43:33Z (a year ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 240619A
(Fermi-GBM detection: The Fermi GBM team, GCN 36694;
CALET-CGBM detection: Torii et al., GCN 36719;
GRBAlpha detection: Dafcikova et al., GCN 36724;
GOTO OT detection: Gompertz et al., GCN 36715;
Swift-XRT afterglow detection: Capalbi et al., GCN 36721)
triggered Konus-Wind at T0=13408.204 s UT (03:43:28.204).
The burst light curve shows two separated emission episodes.
The initial harder episode starts at ~T0-0.2 s and has a total duration of ~14 s. The following softer episode starts at ~T0+22 s and ends at ~T0+36 s. The total burst duration is ~36 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240619_T13408/
As observed by Konus-Wind, the burst
had a fluence of 1.35(-0.36,+0.79)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.052 s,
of 1.48(-0.50,+0.49)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+41.216 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.62(-0.21,+0.32)
and Ep = 557(-300,+4475) keV (chi2 = 93/86 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 93/85 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.60(-0.52,+0.86),
the high energy photon index beta = -1.98(-8.02,+0.25),
the peak energy Ep = 480(-218,+870) keV
(chi2 = 29/40 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 36813
Subject
GRB 240619A: Host galaxy redshift from VLT/X-shooter
Date
2024-07-03T15:58:09Z (a year ago)
Edited On
2024-09-30T20:29:48Z (10 months ago)
From
Laura Cotter <laura.cotter@ucdconnect.ie>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Aishwarya L Thakur at INAF-IAPS, Rome <aishth@outlook.com>
Via
Web form
L. Cotter (UCD), B. Schneider (MIT), D. Xu (NAOC), J. T. Palmerio (GEPI, Obs. de Paris), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. de Ugarte Postigo (CNRS, OCA, LAM), G. Pugliese (Amsterdam), B. P. Gompertz (Birmingham), A. Martin-Carrillo (UCD), A. Rossi (INAF), D. Hartmann (Clemson Univ.), A.L. Thakur (INAF), N. R. Tanvir (Leicester), A. J. Levan (Radboud) report on behalf of the Stargate collaboration:
We observed the location (Gompertz et al., GCN 36715; Capalbi et al., GCN 36721; Mo et al., GCN 36739; Rhodes et al., GCN 36744) of the Fermi GRB 240619A (Fermi GBM team, GCN 36694; Preis et al., GCN 36695; Dalessi et al., GCN 36717) using the X-shooter spectrograph mounted on the ESO VLT UT3 (Melipal). The observation was performed on 2024 July 02 (13.8 days after the GRB). It consisted of 4 exposures of 600 s each and covered the wavelength range 3000-21000 AA.
The target is faintly detected in the r-band acquisition image, with an AB magnitude r ~ 22.8 (calibration is difficult due to paucity of calibrators in the field). This is significantly brighter than the archival object visible in the Pan-STARRS and Legacy surveys, first noticed by Gompertz et al. (GCN 36715), and likely includes a transient contribution.
In a preliminary reduction, we detect several strong emission lines that we identify as H-alpha, H-beta, H-gamma, the [O II] doublet, [O III] 4959, [O III] 5007, and [Ne III] 3869 at a common redshift of z = 0.3965, which is lower than the photometric value reported in the PS1-STRM catalog (Beck et al. 2020) for galaxy PSO J162.3946+17.2828. We therefore propose this to be the redshift of the GRB.
The Legacy survey images also show a second, fainter object about 1.7" west of the optical afterglow position. This was also included in the slit, and we measure for it z = 1.338 from detection of [O II] and H-alpha. Given the larger offset, we consider this galaxy to be unrelated to the GRB.
We acknowledge expert support from the ESO staff in Paranal, in particular Matias Jones and Thomas Szeifert.