TITLE: GCN CIRCULAR
NUMBER: 36486
SUBJECT: Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
DATE: 24/05/15 15:56:14 GMT
FROM: Cori Fletcher at USRA <cfletcher(a)usra.edu>
The Fermi Gamma-ray Burst Monitor Team Reports:
"The Fermi Gamma-ray Burst Monitor (GBM) triggered on several events during the solar storm from May 8 to May 14, 2024. The following events were tentatively classified as a GRB, but are in fact not due to a GRB and likely due to local particles or solar flares.
240511860 / 737152719
240512038 / 737168073
240512165 / 737179077
240512368 / 737196587
240512624 / 737218721
240513086 / 737258655
240513213 / 737269618
Previous circulars sent for similar events: GCN 36441, 36440, 36439, 36433, 36424, 36418, 36415.
We advise the community that due to the current solar activity, GBM is triggering
regularly on similar events."
View this GCN Circular online at https://gcn.nasa.gov/circulars/36486.
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TITLE: GCN CIRCULAR
NUMBER: 36485
SUBJECT: GRB 240514E: MAXI/GSC detection of a probable afterglow
DATE: 24/05/15 14:59:05 GMT
FROM: Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi(a)nihon-u.ac.jp>
H. Negoro (Nihon. U). S. Ogawa (JAXA), W. Iwakiri (Chiba U.), M. Nakajima, Y. Kudo, H. Shibui,
K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada,
S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN),T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo,
H. Hiramatsu, H. Nishikawa, Y. Kondo, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.),
M. Shidatsu, Y. Niida (Ehime U.),I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada (Kyoto U.),
M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), and
M. Sugizaki (NAOC)
The MAXI/GSC detected an uncatalogued X-ray transient source at 19:04 UT
on May 14, 2024. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (76.718 deg, -21.544 deg) = (05 06 52, -21 32 38) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.61 deg and 0.42 deg, respectively.
The roll angle of long axis from the north direction is 131.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 100 +- 23 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 17:32 UT
with an upper limit of 20 mCrab. No observation for the region was made
for more than 19 hours after the detection.
The source did not show significant rapid variations during the scan.
Given a relatively high galactic longitude, (l, b) = (222.1, -32.2),
and the spectral softness, the source is most likely a GRB afterglow.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36485.
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TITLE: GCN CIRCULAR
NUMBER: 36484
SUBJECT: GRB 240514B: GRBAlpha detection
DATE: 24/05/15 13:00:41 GMT
FROM: Jakub Ripa <ripa.jakub(a)gmail.com>
J. Ripa, M. Dafcikova, 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 short-duration GRB 240514B (Fermi/GBM detection: GCN 36481; INTEGRAL/SPI-ACS peak detection at 2024-05-14 ~04:03:45 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 2024-05-14 04:03:44.7 UTC. The T90 duration measured by GRBAlpha is 1.0 s and the overall significance during T90 reaches 6.1 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240514B_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.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36484.
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TITLE: GCN CIRCULAR
NUMBER: 36483
SUBJECT: LIGO/Virgo/KAGRA S240514x: Updated Sky localization
DATE: 24/05/15 03:43:12 GMT
FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki(a)ligo.org>
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240514x (GCN Circular 36476). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S240514x
For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 142 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2594 +/- 587 Mpc (a posteriori mean +/- standard deviation).
For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/.
[1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380
View this GCN Circular online at https://gcn.nasa.gov/circulars/36483.
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TITLE: GCN CIRCULAR
NUMBER: 36482
SUBJECT: LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
DATE: 24/05/15 02:35:27 GMT
FROM: Chia-Hsuan Hsiung <sw56540(a)gmail.com>
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We identified the compact binary merger candidate S240515m during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-05-15 00:53:01.114 UTC (GPS time: 1399769599.114). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines.
S240515m is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.3e-21 Hz, or about one in 1e13 years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S240515m
The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%).
There was a significant noise transient (glitch) in the Virgo detector near the event time which may affect the localization of the candidate.
Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%.
Two sky maps are available at this time and can be retrieved from the GraceDB event page:
* bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 31 seconds after the candidate event time.
* bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time.
The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 978 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3559 +/- 976 Mpc (a posteriori mean +/- standard deviation).
For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/.
[1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004
[2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625
[3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913
[4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913
[5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
[6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
View this GCN Circular online at https://gcn.nasa.gov/circulars/36482.
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TITLE: GCN CIRCULAR
NUMBER: 36481
SUBJECT: GRB 240514B: Fermi GBM Detection
DATE: 24/05/14 22:49:03 GMT
FROM: Oliver J Roberts at USRA/NASA <oliver.roberts(a)nasa.gov>
O.J. Roberts (USRA-NASA/MSFC) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 04:03:45.04 UT on 14 May 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240514B (trigger 737352230/240514169).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 5.1, Dec = 44.5 (J2000 degrees, equivalent to J2000 22h 47m, -1d 19'),
with a statistical uncertainty of 4.0 degrees. 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).
This is an improved localization that replaces the Final Position notice
GCN sent out earlier (Fermi GBM Team, 2021, GCN 36469).
The angle from the Fermi LAT boresight is 111 degrees.
The GBM light curve shows two bright peaks with a duration (T90)
of about 1.7 s (50-300 keV). The time-averaged spectrum
from T0-0.06 to T0+0.70 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.75 +/- 0.07 and the cutoff energy,
parameterized as Epeak, is 957 +/- 130 keV.
The event fluence (10-1000 keV) in this time interval is
(2.7 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.32 s in the 10-1000 keV band is 16 +/- 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/"
View this GCN Circular online at https://gcn.nasa.gov/circulars/36481.
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TITLE: GCN CIRCULAR
NUMBER: 36479
SUBJECT: GRB 240513A: Fermi GBM observation
DATE: 24/05/14 15:49:19 GMT
FROM: Elisabetta Bissaldi at Politecnico and INFN Bari <elisabetta.bissaldi(a)ba.infn.it>
E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 07:22:02 UT on 13 May 2024, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 240513A (trigger 737277727 / 240513307),
which was also detected by the Fermi/LAT (Cutini et al. 2024, GCN 36462)
and AstroSat CZTI (Joshi et al. 2024, GCN 36455).
The GBM on-ground location is consistent with the LAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 34 degrees.
The GBM light curve consists of two emission episodes
with a duration (T90) of about 7 s (50-300 keV).
The time-averaged spectrum from T0-0.3 s to T0+6.5 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.87 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 1700 +/- 400 keV.
The event fluence (10-1000 keV) in this time interval is
(3.93 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.8 s in the 10-1000 keV band
is 4.1 +/- 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/"
View this GCN Circular online at https://gcn.nasa.gov/circulars/36479.
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TITLE: GCN CIRCULAR
NUMBER: 36478
SUBJECT: GRB 240513A: Swift-XRT observations
DATE: 24/05/14 14:35:11 GMT
FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk>
M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. Tohuvavohu (U. Toronto),
D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U. Leicester),
J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA) 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 240513A in a series of observations tiled
on the sky. The total exposure time is 5.1 ks, distributed over 7
tiles; the maximum exposure at a single sky location was 1.6 ks. The
data were collected between T0+46.1 ks and T0+80.7 ks, and are entirely
in Photon Counting (PC) mode.
Three uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:
Source 2:
RA (J2000.0): 163.8237 = 10:55:17.69
Dec (J2000.0): -27.6225 = -27:37:20.9
Error: 9.7 arcsec (radius, 90% conf.)
Count-rate: (8.6 [+4.8, -3.5])e-3 ct s^-1
Distance: 1422 arcsec from Fermi/LAT position.
Source 4:
RA (J2000.0): 163.9338 = 10:55:44.10
Dec (J2000.0): -27.5934 = -27:35:36.2
Error: 7.6 arcsec (radius, 90% conf.)
Count-rate: (7.4 [+4.8, -3.4])e-3 ct s^-1
Distance: 1736 arcsec from Fermi/LAT position.
Source 6:
RA (J2000.0): 163.4544 = 10:53:49.05
Dec (J2000.0): -27.4116 = -27:24:41.7
Error: 5.1 arcsec (radius, 90% conf.)
Count-rate: 0.0224 [+0.0072, -0.0060] ct s^-1
Distance: 362 arcsec from Fermi/LAT position.
Flux: (1.64 [+0.53, -0.44])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Two catalogued sources were also detected.
The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00125.
This circular is an official product of the Swift-XRT team.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36478.
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