TITLE: GCN CIRCULAR
NUMBER: 35848
SUBJECT: GRB 240225B: Glowbug gamma-ray detection
DATE: 24/03/03 04:22:32 GMT
FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil>
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240225B, which was also detected by MAXI/GSC (GCN 35796), AstroSat/CZTI (GCN 35798), CALET (GCN 35811), and Konus/Wind (GCN 35835).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-25 20:11:58.416 with a duration of 38.9 s and a total significance of ~89 sigma. The light curve comprises a multi-peaked structure with two primary peaks at ~T0+3s and ~T0+8s, and a fainter peak at ~T0+34s.
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission in two defined intervals from T0 to T0+22.5s and T0+22.5s to +38.9s resulted respectively in photon indices dN/dE~E^x of x=0.6 and x=0.7, and cutoff energies ("Epeak") of 324 keV and 262 keV. The respective modeled 10-10000 keV fluences are 9.7e-06 erg/cm^2 and 2.0e-06 erg/cm^2.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
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TITLE: GCN CIRCULAR
NUMBER: 35847
SUBJECT: IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
DATE: 24/03/03 00:57:55 GMT
FROM: Alicia Mand at IceCube/UW-Madison <aemand(a)wisc.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-240229A (https://gcn.nasa.gov/circulars/35841) in a time range of 1000 seconds centered on the alert event time (2024-02-29 15:40:01.510 UTC to 2024-02-29 15:56:41.510 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-240229A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-240229A is 1.4e-01 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 1e+05 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2024-02-28 15:48:21.510 UTC to 2024-03-01 15:48:21.510 UTC). In this case, we report a p-value of 0.03, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-240229A is 1.6e-01 GeV cm^-2 in a 2 day time window.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)
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TITLE: GCN CIRCULAR
NUMBER: 35846
SUBJECT: GRB 240225C: Glowbug gamma-ray detection
DATE: 24/03/02 14:35:03 GMT
FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil>
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240225C, which was also detected by AstroSat/CZTI (GCN 35799), GRBAlpha (GCN 35802), CALET (GCN 35806), INTEGRAL/SPI-ACS (Trigger 10590), and Konus/Wind (Trig_Time 05:19:33.355).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-25 05:19:33.944 with a duration of 13.8 s and a total significance of about 83 sigma. The light curve comprises a single peak.
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.5 and a cutoff energy ("Epeak") of 270 keV. The modeled 10-10000 keV fluence is 6.4e-06 erg/cm^2.
The best-fit localization is RA, Decl. (J2000, deg) = 351.0, 25.7 with a radius of 4.2 deg (95% confidence), with a highly uncertain systematic uncertainty.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
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TITLE: GCN CIRCULAR
NUMBER: 35845
SUBJECT: GRB 240225A (short): Glowbug gamma-ray detection
DATE: 24/03/02 14:34:30 GMT
FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil>
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of the short GRB 240225A, which was also detected by Swift/BAT (GCN 35793) and INTEGRAL/SPI-ACS (Trigger 10589).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-25 04:20:17.488 with a duration of 2.05 s and a total significance of about 25.4 sigma. The light curve comprises a single peak.
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=0.04 and a cutoff energy ("Epeak") of 670 keV. The modeled 10-10000 keV fluence is 1.6e-06 erg/cm^2.
The best-fit localization is RA, Decl. (J2000, deg) = 82.5,-37.9 with a radius of 14.3 deg (95% confidence), with a highly uncertain systematic uncertainty.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
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TITLE: GCN CIRCULAR
NUMBER: 35844
SUBJECT: GRB 240229A: DDOTI Upper Limits on the Afterglow
DATE: 24/03/02 00:54:46 GMT
FROM: Kin O. C. L. Mendoza at Instituto de Astronoma, UNAM <koclopez(a)astro.unam.mx>
Océlotl Lopez (UNAM), Alan M. Watson (UNAM), Rosa L. Becerra (Tor
Vergata Roma),
Margarita Pereyra (UNAM), Nat Butler (ASU), Simone Dichiara (Penn state
university), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD),
Tsvetelina Dimitrova (ASU) and Eleonora Troja (Tor Vergata Roma) report:
We observed the field of the Fermi GBM GRB 240229A (Fermi GBM team 2024,
GCN Circ. 35833) with the DDOTI wide-field imager at the Observatorio
Astronómico Nacional on Sierra San Pedro Mártir (
http://ddoti.astroscu.unam.mx) from 2024-03-01 06:10:00 to 12:58:45 UTC
(16.05 to 22.86 hours after the trigger).
We observed a region of 7 degrees in RA by 7 degrees in declination
centered on the Fermi GBM Final Position of RA = 199.18 and Dec = 16.77
(J2000 degrees). This region contains 1 instrumental field or about 49
square degrees. We obtained 103 minutes of exposure per instrumental field
in the w filter. We obtained AB photometry by calibration against the APASS
catalog.
We detect no likely candidates for the afterglow to our 10-sigma upper
limits of w = 19.90 - 20.64 (inter-quartile).
We thank the staff of the Observatorio Astronómico Nacional on San Pedro
Mártir.
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TITLE: GCN CIRCULAR
NUMBER: 35843
SUBJECT: GRB 240218A: NOEMA upper limit
DATE: 24/03/01 16:27:52 GMT
FROM: Antonio de Ugarte Postigo at OCA <deugarte(a)oca.eu>
A. de Ugarte Postigo (CNRS/OCA & LAM), T. Laskar (Utah), M. Bremer (IRAM),
C. C. Thoene (ASU-CAS), J. F. Agui Fernandez (CAHA), S. Antier (OCA), S. Basa (LAM), M. Michalowski (AOI-AMU), D. A. Perley (LJMU), S. Martin (ESO, ALMA),
K. D. Alexander (Arizona), E. Berger (Harvard), R. Chornock (Berkeley), W. Fong (Northwestern), R. Margutti (UC Berkeley), C. Peña (Utah), P. Schady (Bath), G. Schroeder (Northwestern),
report:
We observed the field of GRB 240218A (Page et al. 35742, Svinkin et al. GCN 35758) at a redshift of z = 6.782 (Saccardi et al. GCN 35756) with NOEMA at 74 and 90 GHz at a mean epoch 10.88 days after the burst.
Our observations show no detection of the afterglow (D’Avanzo et al. GCN 35747, Malesani et al. GCN 35749, Rossi et al. GCN 35762, Schroeder et al. GCN 35794) down to a 3-sigma limit of 65 microJy.
Based on observations carried out under project number W23DI with the IRAM NOEMA Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
View this GCN Circular online at https://gcn.nasa.gov/circulars/35843.
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TITLE: GCN CIRCULAR
NUMBER: 35842
SUBJECT: GRB 240229A: CALET Gamma-Ray Burst Monitor detection
DATE: 24/03/01 04:42:26 GMT
FROM: Yuta Kawakubo at Louisiana State University <kawakubo1(a)lsu.edu>
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,
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 240229 (Fermi GBM Final Real-time Localization:
Fermi GBM team, GCN Circ. 35833; BALROG localization: Biltzinger et al.,
GCN Circ 35834; INTEGRAL SPI ACS: Trigger Num. 10602)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at
14:07:07.40 UTC on 29 February 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1393250567/).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked structure that starts
at T+2.9 sec, peaks at T+26.5 sec, and ends at T+36.8 sec.
The T90 and T50 durations measured by the SGM data are 27.6 +/- 2.5 sec
and 19.2 +/- 0.4 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1393250567/index.html
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35842.
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TITLE: GCN CIRCULAR
NUMBER: 35841
SUBJECT: IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
DATE: 24/03/01 00:32:04 GMT
FROM: Marcos Santander at U of Alabama <jmsantander(a)ua.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2024-02-29 at 15:48:21.52 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_Bronze alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 1.336 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.
After the initial automated alert, more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2024-02-29
Time: 15:48:21.52 UT
RA: 72.25 (+1.28, -1.26 deg 90% PSF containment) J2000
Dec: +15.79 (+1.08, -0.92 deg 90% PSF containment) J2000
We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.
There is one known Fermi-LAT source (either in the 4FGL-DR4 or 3FHL catalogs) located within the 90% uncertainty region of the event: 4FGL J0445.7+1535, located at RA: 71.44 deg, Dec: 15.60 deg J2000 (0.81 deg away from the best-fit event position).
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu
View this GCN Circular online at https://gcn.nasa.gov/circulars/35841.
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