GRB 240118A
GCN Circular 35607
Subject
GRB 240118A: Swift/UVOT Upper Limits
Date
2024-01-23T17:35:39Z (2 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
Via
Web form
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240118A
96191 s after the LAT trigger (Bissaldi et al., GCN Circ. 35560). No optical afterglow consistent with the
LAT position or the XRT position (Beardmore et al., GCN Circ. 35587) 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 96191 103639 3161 >20.8
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.056 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 35588
Subject
GRB 240118A: Mondy optical observations
Date
2024-01-20T23:54:29Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of IKI GRB FuN:
We observed the field of Fermi LAT localization of GRB 240118A (Bissaldi, GCN 35560), which was also detected by Fermi GBM (Fermi GBM team, GCN 35558; Hamburg, GCN 35563), NuSTAR (Grefenstette, GCN 35564), Konus-Wind (Frederiks, GCN 35567), Swift BAT (DeLaunay, GCN 35568), and GRBAlpha (Dafcikova et al., GCN 35580), and the localization area observed by MASTER-Tunka observatory (Lipunov et al., GCN 35561) and Abastumani observatory (Pankov et al., GCN 35572).
Observations started on 2024-01-18 (UT) 14:13:46 with AZT-33IK telescope of Sayan observatory (Mondy) in the R-filter. The observations have been carried out in moderate weather conditions with FWHM of 2.5". We report observations of XRT candidates detected in the Swift TOO program (Evans et al., GCN 35573).
XRT #1 - out of FOV
XRT #2 - matches bright USNO-B1.0 star with R2=9.98 mag
XRT #3 - within the XRT #3 error circle we detect a faint source, which matches SDSS J011408.49+294753.1 source with SDSS DR12 r'= 22.117 and redshift of z_phot = 0.68
XRT #4 - out of FOV
XRT #5 - matches bright Gaia DR3 star with G=6.48 mag
XRT #6 - out of FOV
XRT #7 - out of FOV
Preliminary photometry of the faint source XRT #3 suggested as an X-ray afterglow (Beardmore et al., GCN 35587) is following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2024-01-18 14:13:46 0.537932 R 29*120 22.1 0.3 22.1
The photometry is based on nearby USNO-B1.0 stars.
At this time we cannot say anything about the variability of the source. The source at coordinates 01:14:08.48 +29:47:53.2, spatially coinciding with the galaxy SDSS J011408.49+294753.1 with a redshift of 0.68 could be a host galaxy of GRB 240118A.
GCN Circular 35587
Subject
GRB 240118A: Swift-XRT afterglow detection
Date
2024-01-20T22:41:31Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi
(INAF-IASFPA) , M. Capalbi (INAF-IASFPA), A. Tohuvavohu (U. Toronto),
D.N. Burrows (PSU), J. D. Gropp (PSU), 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/LAT-detected burst GRB 240118A, collecting 4.7 ks of Photon
Counting (PC) mode data between T0+96.2 ks and T0+109.0 ks.
Two uncatalogued X-ray sources are detected consistent with being
within 296 arcsec of the Fermi/LAT position, of which one ("Source 3")
is believed to be the afterglow. Using 4697 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 = 18.53587, +29.79798 which is equivalent to:
RA (J2000): 01h 14m 08.61s
Dec(J2000): +29d 47' 52.7"
with an uncertainty of 2.7 arcsec (radius, 90% confidence). This
position is 2.1 arcmin from the Fermi/LAT position. The light curve is
consistent with a constant source of mean count rate 3.6e-02 ct/sec. A
power-law fit gives an index of 1.9 (+1.0, -2.8).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.2 (+/-0.6). The
best-fitting absorption column is 1.1 (+0.8, -0.6) x 10^22 cm^-2, in
excess of the Galactic value of 7.1 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 4.5 x 10^-11 (9.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.1 (+0.8, -0.6) x 10^22 cm^-2
Galactic foreground: 7.1 x 10^20 cm^-2
Excess significance: 3.1 sigma
Photon index: 2.2 (+/-0.6)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021644.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021644.
This circular is an official product of the Swift-XRT team.
GCN Circular 35580
Subject
GRB 240118A: GRBAlpha detection
Date
2024-01-19T17:40:49Z (2 years ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (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. Kolar, 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 bright long-duration GRB 240118A (Fermi/GBM detection: GCN 35558; Fermi/LAT detection: GCN 35560; NuSTAR detection: GCN 35564; Konus/Wind detection: GCN 35567; Swift/BAT detection: GCN 35522; INTEGRAL/SPI-ACS detection: trigger no. 10477) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).
The detection was confirmed at the peak time 2024-01-18 01:49:22 UTC. The T90 duration measured by GRBAlpha is 58 s and the overall significance during T90 reaches 174 sigma.
The light curve shows a multiple-peaked structure which is consistent with light curves observed by other missions. However, GRBAlpha was passing through the van Allen radiation belt during the entire burst duration and therefore the measured count rate is subject to a higher variable background which cannot be distinguished from the burst itself.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240118A_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 35573
Subject
GRB 240118A: Swift ToO observations
Date
2024-01-19T04:29:59Z (2 years 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/LAT GRB 240118A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021644
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 35572
Subject
GRB 240118A: AbAO optical upper limit
Date
2024-01-19T01:25:42Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), S. Belkin (IKI) report on behalf of IKI GRB FuN:
We observed the field of Fermi LAt localization of GRB 240118A (Bissaldi, GCN 35560) and detected also Fermi GBM (Fermi GBM team, GCN 35558; Hamburg, GCN 35563), NuSTAR (Grefenstette, GCN 35564), Swift BAT (DeLaunay, GCN 35568), and Konus-Wind (Frederiks, GCN 35567) with AS-32 telescope of Abastumani observatory (AbAO) in R-filter starting on 2024-01-18 (UT) 16:47:55. No optical candidate is detected in the LAT localization area (Bissaldi, GCN 35560