TITLE: GCN CIRCULAR
NUMBER: 34274
SUBJECT: IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
DATE: 23/07/27 07:46:04 GMT
FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites(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-230725A (https://gcn.nasa.gov/circulars/34261) in a time range of 1000 seconds centered on the alert event time (2023-07-25 21:22:31.060 UTC to 2023-07-25 21:39:11.060 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-230725A. 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-230725A is 1.3e-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 (2023-07-24 21:30:51.060 UTC to 2023-07-26 21:30:51.060 UTC). In this case, we report a p-value of 1.00, 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-230725A ranges from 1.5e-01 to 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: 34273
SUBJECT: IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
DATE: 23/07/27 00:38:45 GMT
FROM: Jessie Thwaites at IceCube/U Wisc-Madison <thwaites(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-230724A (https://gcn.nasa.gov/circulars/34265) in a time range of 1000 seconds centered on the alert event time (2023-07-24 01:40:53.380 UTC to 2023-07-24 01:57:33.380 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-230724A. 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-230724A is 1.5e-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 3e+02 GeV and 2e+05 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2023-07-23 01:49:13.380 UTC to 2023-07-25 01:49:13.380 UTC). In this case, we report a p-value of 1.00, 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-230724A 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: 34272
SUBJECT: Integral GRB230726.26: Global MASTER-Net observations report
DATE: 23/07/26 18:57:58 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Integral GRB230726.26 (trigger No 10345,02h 43m 39.77s , +61d 39m 22.3s, R=50) errorbox 43577 sec after notice time and 43585 sec after trigger time at 2023-07-26 18:16:08 UT, with upper limit up to 18.3 mag. Observations started at twilight. The observations began at zenith distance = 42 deg. The sun altitude is -10.0 deg.
The galactic latitude b = 2 deg., longitude l = 136 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2245361
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
43676 | MASTER-Tavrida | C | 180 | 17.6 |
43868 | MASTER-Tavrida | C | 180 | 17.6 |
44059 | MASTER-Tavrida | C | 180 | 17.8 |
44251 | MASTER-Tavrida | C | 180 | 17.9 |
44444 | MASTER-Tavrida | C | 180 | 18.3 |
44635 | MASTER-Tavrida | C | 180 | 18.2 |
44828 | MASTER-Tavrida | C | 180 | 18.1 |
45019 | MASTER-Tavrida | C | 180 | 18.2 |
45211 | MASTER-Tavrida | C | 180 | 18.2 |
45403 | MASTER-Tavrida | C | 180 | 18.1 |
45594 | MASTER-Tavrida | C | 180 | 18.3 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
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TITLE: GCN CIRCULAR
NUMBER: 34271
SUBJECT: GRB 230723B: Further CAHA observations and host galaxy detection
DATE: 23/07/26 17:36:30 GMT
FROM: Antonio de Ugarte Postigo at OCA <deugarte(a)oca.eu>
J.F. Agui Fernandez (IAA-CSIC), A. de Ugarte Postigo (OCA/CNRS), C.C. Thoene (ASU-CAS), J. Flores and Ana Guijarro Roman (CAHA) report:
We have performed follow-up observations on the GRB 230723B field (Page et al. GCN 34324, Osborne et al. GCN 34248) with CAFOS in the 2.2m telescope at the Calar Alto Observatory in Almeria, Spain. Observations consisted of 9x360s in i-band, starting at 2023-07-25T20:46:11 UT with a mean epoch 2.393 days after the burst. We detect the object reported in Agui Fernandez et al. (GCN 34251) at a magnitude consistent with our previous observation.
The early optical detection of the transient at a consistent location by Sasada et al. (GCN 34268) indicates that the detection in the first Calar Alto observation was already dominated by the host galaxy contribution. The interpolation from the observation of Sasada et al. (GCN 34251) to the one of Agui Fernandez et al. (GCN 34251) indicates a decay rate of at least alpha=1.1 (where F_nu ~ t^-alpha). Extrapolating this, the GRB afterglow should be dimmer than 24 mag at the time of our follow-up observations. We do note, that the host galaxy should be in the range for emission line spectroscopy with 8-10m telescopes.
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TITLE: GCN CIRCULAR
NUMBER: 34270
SUBJECT: LIGO/Virgo/KAGRA S230726a: Updated Sky localization
DATE: 23/07/26 17:22:24 GMT
FROM: naresh.adhikari(a)ligo.org
The LIGO Scientific Collaboration, the Virgo Collaboration, and the
KAGRA Collaboration report:
We have conducted further analysis of the LIGO Livingston Observatory
(L1) data around the time of the compact binary merger (CBC) candidate
S230726a (GCN Circular 34264).
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/S230726a
For the Bilby.multiorder.fits,0 sky map, the 90% credible region is
27774 deg2. Marginalized over the whole sky, the a posteriori
luminosity distance estimate is 2132 +/- 714 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/userguide/.
[1] Ashton et al. ApJS 241, 27 (2019)
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TITLE: GCN CIRCULAR
NUMBER: 34269
SUBJECT: Konus-Wind detection of GRB 230723A
DATE: 23/07/26 15:06:31 GMT
FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru>
A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short-duration GRB 230723A
(Fermi GBM detection: The Fermi GBM team, GCN 34232;
AGILE/MCAL detection: Panebianco et al., GCN 34237;
IPN triangulation: Kozyrev et al., GCN 34258)
triggered Konus-Wind at T0=16725.802 s UT (04:38:45.802).
The burst light curve shows a multipeaked structure,
which starts at T0-0.346 s and has a total duration of ~0.62 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230723_T16725/
As observed by Konus-Wind, the burst
had a fluence of 1.66(-0.06,+0.54)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.220 s,
of 8.56(-1.76,+3.29)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.
Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.346 s to T0+0.620 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.21(-0.26,+0.27) and Ep = 659(-99,+162) keV.
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.
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TITLE: GCN CIRCULAR
NUMBER: 34268
SUBJECT: GRB 230723B: MITSuME Akeno optical afterglow candidate detection
DATE: 23/07/26 13:34:48 GMT
FROM: Mahito Sasada at Tokyo Institute of Technology <sasada(a)hp.phys.titech.ac.jp>
M. Sasada, I. Takahashi, M. Niwano, S. Sato, S. Hayatsu, N. Higuchi, H. Takei, H. Seki, Y. Yatsu (Tokyo Tech), K. L. Murata (Kyoto U) and N. Kawai (Riken) report on behalf of the MITSuME collaboration:
We observed the field of GRB 230723B (Page et al. GCN Circular #34234, Campana et al. #34236, Page et al. #34238, Lipunov et al. #34239, Siegle et al. #34240, Agui Fernandez et al. #34241, Adami et al. #34247, Osborne et al. #34248, Mangan et al. #34249, Quadri et al. #34250, Agui Fernandez et al. #34251, Leonini et al. #34252, Ruocco et al. #34253, Pavoni et al. #34254, Lopresti et al. #34259, Anderson et al. #34267) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno.
The observation with a series of 10 sec exposures started at 2023-07-23 11:43:20 UT (48 seconds after the Swift/BAT detection). We stacked the images with good conditions. In the stacked image at 454 seconds after the burst, we detected an object of Ic=17.1+/-0.2 at the coordinate reported by Agui Fernandez et al. #34251. We also report the g’-, Rc- and Ic-band 3-sigma upper limits of the stacked images.
T0+[sec] |MID-UT | T-EXP[sec] | 3-sigma limits
------------------------------------------------------------------------------------------------
454 | 2023-07-23 11:50:06 | 220 | g’>18.0, Rc>17.8, Ic>17.6
1419 | 2023-07-23 12:06:11 | 1020 | g’>18.6, Rc>18.5, Ic>18.2
3763 | 2023-07-23 12:45:15 | 1890 | g'>19.0, Rc>18.5, Ic>18.0
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration. The catalog magnitudes in PS1 r and i bands were converted to our Rc- and Ic-band magnitudes following Tonry et al. (2012), Table 6. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
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TITLE: GCN CIRCULAR
NUMBER: 34267
SUBJECT: GRB 230723B: ATCA rapid radio follow-up
DATE: 23/07/26 05:29:00 GMT
FROM: Gemma Anderson at Curtin U <gemma.anderson(a)curtin.edu.au>
G. E. Anderson (Curtin), A. Gulati (USyd), J. K. Leung (USyd), A. J. van der Horst (GWU), L. Rhodes (Oxford), S. Chastain (UNM) on behalf of the PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) performed rapid-response follow-up observations of the long GRB 230723B (Page et al. GCN 34234) at 5.5, 9, 16.7, and 21.2 GHz as part of the Large ATCA “PanRadio GRB” follow-up programme C3542 (PI. Anderson). ATCA was on target observing at 2023-07-23 11:51 UT, just 9 minutes post-burst and observed for 4 hrs. There is no radio source coincident with the enhanced XRT position (Page et al. GCN 34238) with 3 sigma upper limits of 150, 90, 90 and 150 microJy/beam at 5.5, 9.0, 16.7 and 21.2 GHz, respectively. Further observations are planned.
We thank the CSIRO Space and Astronomy staff for supporting these observations and maintaining the ATCA rapid-response observing mode.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
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TITLE: GCN CIRCULAR
NUMBER: 34266
SUBJECT: LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
DATE: 23/07/26 04:36:27 GMT
FROM: acz2122(a)columbia.edu
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
A search for track-like muon neutrino events detected by IceCube consistent with the sky
localization of the low-significance gravitational wave candidate S230726b in a time range of 1000 seconds
centered on the alert event time (2023-07-26 01:06:47 UTC to 2023-07-26 01:23:27 UTC)
has been performed [1,2]. During this time period IceCube was collecting good quality data.
One hypothesis test was conducted for this low-significance gravitational wave event. The
search uses a Bayesian approach to quantify the joint GW + neutrino event significance, which
assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source
distance, in the significance estimate [3].
One track-like event is found in spatial and temporal coincidence with the gravitational-wave
candidate S230726b calculated from the map circulated by LVK as S230726b-2-Preliminary. This
represents an overall pre-trial p-value of 0.0089 for the Bayesian search.
The reported p-value here does not account for any trials correction (multiple hypotheses testing). The false alarm rate of these coincidences can be obtained by multiplying the p-values with their corresponding GW trigger rates. Further details are available at https://gcn.nasa.gov/missions/icecube.
Properties of the coincident event(s) are shown below.
dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(generic transient) p-value(Bayesian)
-----------------------------------------------------------------------------------------------------
80.15 131.82 1.68 1.889 not applicable 0.0098
...
where:
dt = Time of track event minus time of GW trigger (sec)
Angular uncertainty = Angular uncertainty of track event: the radius of a circle
representing 90% CL containment by area.
p-value = the p-value for this specific track event from each search.
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] M. G. Aartsen et al 2020 ApJL 898 L10
[2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80
[3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017
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