TITLE: GCN CIRCULAR
NUMBER: 36796
SUBJECT: LIGO/Virgo/KAGRA S240630t: Updated Sky localization
DATE: 24/06/30 17:06:41 GMT
FROM: Christopher P L Berry at LVK Collaboration <christopher.berry(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 S240630t (GCN Circular 36794). 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/S240630t
For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 670 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3161 +/- 841 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
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TITLE: GCN CIRCULAR
NUMBER: 36795
SUBJECT: LIGO/Virgo/KAGRA S240629by: Updated Sky localization
DATE: 24/06/30 16:59:28 GMT
FROM: Christopher P L Berry at LVK Collaboration <christopher.berry(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 S240629by (GCN Circular 36784). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S240629by
For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 74 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis):
icrs; ellipse(02h04m, +17d20m, 11.98d, 1.99d, 121.16d)
Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1173 +/- 245 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
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TITLE: GCN CIRCULAR
NUMBER: 36794
SUBJECT: LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
DATE: 24/06/30 11:17:00 GMT
FROM: eporcell(a)nikhef.nl
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We identified the compact binary merger candidate S240630t during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-06-30 10:17:03.372 UTC (GPS time: 1403777841.372). The candidate was found by the CWB [1], GstLAL [2], and PyCBC Live [3] analysis pipelines.
S240630t is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-12 Hz, or about one in 1e4 years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S240630t
The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%).
Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] 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 [5], distributed via GCN notice about 23 seconds after the candidate event time.
* bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], 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 1033 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3026 +/- 834 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] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a
[4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
[5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
View this GCN Circular online at https://gcn.nasa.gov/circulars/36794.
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TITLE: GCN CIRCULAR
NUMBER: 36793
SUBJECT: LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
DATE: 24/06/30 02:18:52 GMT
FROM: Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma(a)nasa.gov>
V. Sharma (NASA GSFC/UMBC) reports on behalf of the Fermi-GBM Team:
For S240629by (GCN 36784) and using the initial bayestar skymap, Fermi-GBM was observing 17.8% of the localization probability at event time.
There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S240629by. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates.
Part of the LVK localization region is behind the Earth for Fermi, located at an RA=30.0, Dec=-25.6 with a radius of 67.4 degrees. We therefore set upper limits on impulsive gamma-ray emission for the GW localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2):
Timescale Soft Normal Hard
------------------------------------
0.128 s: 2.1 3.5 7.2
1.024 s: 0.7 1.1 2.1
8.192 s: 0.3 0.5 0.9
Assuming the median luminosity distance of 1205 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128s: 0.6 0.8 2.9
1.024s: 0.2 0.3 0.8
8.192s: 0.1 0.1 0.4
View this GCN Circular online at https://gcn.nasa.gov/circulars/36793.
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TITLE: GCN CIRCULAR
NUMBER: 36792
SUBJECT: LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
DATE: 24/06/30 01:06:11 GMT
FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita(a)phys.aoyama.ac.jp>
M. Nakajima, H. Negoro, K. Takagi (Nihon U.),
N. Kawai, T. Mihara, (RIKEN),
S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU)
report on behalf of the MAXI team:
We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after compact binary merger candidate S240629by at 2024-06-29 14:52:56.859 UTC (GCN 36784).
At the trigger time of S240629by, the high-voltage of MAXI/GSC was off,
and it was turned on at T0+1589 sec (+26.5 min).
The first one-orbit (92 min) scan observation with GSC after the event covered 80%
of the 90% credible region of the bayestar skymap (bayestar.multiorder.fits,1) from 15:39:13 to 15:41:23 UTC (T0+2777 to T0+2907 sec).
No significant new source was found in the region in the one-orbit scan observation.
A typical 1-sigma averaged upper limit obtained in one scan observation
is 20 mCrab at 2-20 keV.
If you require information about X-ray flux by MAXI/GSC at specific coordinates,
please contact the submitter of this circular by email.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36792.
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TITLE: GCN CIRCULAR
NUMBER: 36791
SUBJECT: Fermi trigger No 741356809: Global MASTER-Net observations report
DATE: 24/06/29 23:30:34 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, 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB240629.52 (trigger No 741356809,01h 42m 28.80s , -29d 16m 48.0s, R=5.63) errorbox 37803 sec after notice time and 37829 sec after trigger time at 2024-06-29 22:57:13 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 79 deg. The sun altitude is -80.6 deg.
The galactic latitude b = -78 deg., longitude l = 225 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2512447
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
37859 | 2024-06-29 22:57:13 | MASTER-SAAO | (01h 22m 11.07s , -33d 07m 03.2s) | C | 60 | 18.9 |
38131 | 2024-06-29 23:01:45 | MASTER-SAAO | (01h 20m 25.56s , -31d 11m 15.3s) | C | 60 | 18.9 |
38869 | 2024-06-29 23:14:03 | MASTER-SAAO | (01h 22m 16.91s , -33d 06m 45.3s) | C | 60 | 15.3 |
38948 | 2024-06-29 23:15:22 | MASTER-SAAO | (01h 31m 47.42s , -33d 05m 15.2s) | C | 60 | 16.7 |
39202 | 2024-06-29 23:19:36 | MASTER-SAAO | (01h 20m 24.99s , -31d 12m 23.6s) | C | 60 | 17.3 |
39281 | 2024-06-29 23:20:55 | MASTER-SAAO | (01h 29m 48.10s , -31d 11m 09.0s) | C | 60 | 15.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36791.
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TITLE: GCN CIRCULAR
NUMBER: 36790
SUBJECT: Fermi GRB 240629A: Global MASTER-Net observations report
DATE: 24/06/29 18:45:51 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, 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240629A ( Fermi GBM team, GCN 36786) errorbox 3278 sec after notice time and 3311 sec after trigger time at 2024-06-29 17:49:04 UT, with upper limit up to 15.4 mag. The observations began at zenith distance = 80 deg. The sun altitude is -25.7 deg.
The galactic latitude b = -41 deg., longitude l = 4 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2512867
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
3342 | 2024-06-29 17:49:04 | MASTER-SAAO | (20h 42m 14.15s , -40d 38m 12.5s) | C | 60 | 15.4 |
4274 | 2024-06-29 18:04:36 | MASTER-SAAO | (20h 42m 16.65s , -40d 39m 00.0s) | C | 60 | 14.7 |
4512 | 2024-06-29 18:08:35 | MASTER-SAAO | (20h 43m 44.62s , -36d 52m 01.5s) | C | 60 | 12.7 |
4751 | 2024-06-29 18:12:33 | MASTER-SAAO | (20h 37m 14.45s , -38d 45m 36.9s) | C | 60 | 15.0 |
4910 | 2024-06-29 18:15:12 | MASTER-SAAO | (20h 51m 47.88s , -40d 38m 24.9s) | C | 60 | 14.1 |
5227 | 2024-06-29 18:20:30 | MASTER-SAAO | (20h 42m 13.74s , -40d 38m 12.0s) | C | 60 | 12.8 |
5782 | 2024-06-29 18:29:44 | MASTER-SAAO | (20h 37m 14.76s , -38d 45m 58.6s) | C | 60 | 12.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
View this GCN Circular online at https://gcn.nasa.gov/circulars/36790.
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TITLE: GCN CIRCULAR
NUMBER: 36789
SUBJECT: Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
DATE: 24/06/29 17:59:46 GMT
FROM: Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma(a)nasa.gov>
V Sharma (NASA GSFC/UMBC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:
"The Fermi Gamma-ray Burst Monitor (GBM) trigger 741362867/240629589 at 14:07:42.70 UT
on 29 June 2024, tentatively classified as a GRB, is in fact not due
to a GRB. This trigger is likely due to local particles."
View this GCN Circular online at https://gcn.nasa.gov/circulars/36789.
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TITLE: GCN CIRCULAR
NUMBER: 36788
SUBJECT: Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
DATE: 24/06/29 17:44:05 GMT
FROM: sumanbala2210(a)gmail.com
S. Bala (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:
"The Fermi Gamma-ray Burst Monitor (GBM) trigger 741288821/240628732 at 17:33:36.82 UT
on 28 June 2024, tentatively classified as a GRB by BALROG (Preis et.al. 2024, GCN 36779),
is in fact not due to a GRB. This trigger is likely due to local particles."
View this GCN Circular online at https://gcn.nasa.gov/circulars/36788.
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TITLE: GCN CIRCULAR
NUMBER: 36787
SUBJECT: GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
DATE: 24/06/29 17:19:34 GMT
FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de>
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
741372837 at 16:53:52 on 29 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) = 317.4 deg
Decl.(2000.0) = -47.8 deg
The 1 sigma statistical error radius is 3.5 deg.
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240629704/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240629704/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240629704/json
View this GCN Circular online at https://gcn.nasa.gov/circulars/36787.
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