September 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 35470] LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
by GCN Circulars 19 Sep '24

19 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37552 SUBJECT: LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate DATE: 24/09/19 06:57:46 GMT FROM: Allen1711449(a)gmail.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240919bn during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-09-19 06:15:59.193 UTC (GPS time: 1410761777.193). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S240919bn is an event of interest because its false alarm rate, as estimated by the online analysis, is 4e-20 Hz, or about one in 1e12 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240919bn The classification of the GW signal, in order of descending probability, is BBH (>99%), BNS (<1%), NSBH (<1%), or Terrestrial (<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%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. 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 [8], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], 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 well fit by an ellipse with an area of 21 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(03h35m, +36d41m, 3.36d, 2.01d, 82.47d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1828 +/- 383 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] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/37552. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35469] EP240918a: Swift-XRT observation
by GCN Circulars 19 Sep '24

19 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37551 SUBJECT: EP240918a: Swift-XRT observation DATE: 24/09/19 03:02:42 GMT FROM: Jonathan Quirola at Radboud University <jaquirola1990(a)gmail.com> J. Quirola-Vasquez (Radboud Univ.), P. G. Jonker (Radboud Univ), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Martin-Carrillo (UCD), A. J. Levan (Radboud Univ. & Warwick Univ.), F. E. Bauer (PUC), J. van Dalen (Radboud Univ.), M. E. Ravasio (Radboud Univ.), D. Mata Sanchez (IAC), M. A. P. Torres (IAC) report on behalf of a larger collaboration: We observed the location of the X-ray counterpart of the fast X-ray transient EP240918a reported by the Einstein Probe WXT instrument and FXT (Zhang et al. GCN 37541) using the Swift-XRT Observatory target of opportunity (ObsID: 00016827001). The observation started at 2024-09-18T22:05:49 UT, (i.e. ~10.7 hrs after the X-ray trigger) and lasted for ~1 ksec. The XRT PC mode was used. We do not detect an X-ray counterpart to the transient. The Swift automatic analysis (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8) results in an upper limit of ~1.5E-2 cnt/s. Assuming an absorbed power law model with photon index 1.5 and column density 2.0E20 cm-2, we obtain a flux upper limit of <6.9E-13 erg cm-2 s-1 (0.3-10 keV). We thank the Neil Gehrels Swift Observatory team for making the X-ray observation possible. View this GCN Circular online at https://gcn.nasa.gov/circulars/37551. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35468] Fermi GRB 240918A: Global MASTER-Net observations report
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37550 SUBJECT: Fermi GRB 240918A: Global MASTER-Net observations report DATE: 24/09/18 23:30:50 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 240918A ( Fermi GBM team, GCN 37549) errorbox 8469 sec after notice time and 8476 sec after trigger time at 2024-09-18 23:16:27 UT, with upper limit up to 13.1 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -11.0 deg. The galactic latitude b = 61 deg., longitude l = 18 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2607032 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 8507 | 2024-09-18 23:16:27 | MASTER-OAFA | (14h 49m 57.03s , +19d 01m 43.5s) | C | 60 | 12.0 | 8770 | 2024-09-18 23:20:50 | MASTER-OAFA | (15h 06m 05.69s , +19d 01m 26.3s) | C | 60 | 12.7 | 8990 | 2024-09-18 23:24:30 | MASTER-OAFA | (14h 48m 30.08s , +15d 13m 06.5s) | C | 60 | 13.1 | 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/37550. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35467] GRB 240918A: Fermi GBM Final Real-time Localization
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37549 SUBJECT: GRB 240918A: Fermi GBM Final Real-time Localization DATE: 24/09/18 21:04:21 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 20:55:11 UT on 18 Sep 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240918A (trigger 748385716.160644 / 240918872). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 221.6, Dec = 17.0 (J2000 degrees, equivalent to J2000 14h 46m, 17d 00'), with a statistical uncertainty of 10.4 degrees. The angle from the Fermi LAT boresight is 86.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240918872/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240918872/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240918872/… View this GCN Circular online at https://gcn.nasa.gov/circulars/37549. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35466] EP EP240918a: Global MASTER-Net observations report
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37548 SUBJECT: EP EP240918a: Global MASTER-Net observations report DATE: 24/09/18 17:18:36 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the EP EP240918a ( EP Team et al., GCN 37541) errorbox 151 sec after notice time and 7592 sec after trigger time at 2024-09-18 13:31:09 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 11 deg. The sun altitude is -21.2 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP EP240918a errorbox 11305 sec after notice time and 18746 sec after trigger time at 2024-09-18 16:37:03 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 6 deg. The sun altitude is -9.7 deg. The galactic latitude b = 15 deg., longitude l = 78 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2606210 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 7623 | 2024-09-18 13:31:09 | MASTER-Tunka | (19h 18m 13.42s , +46d 08m 39.1s) | C | 60 | 18.7 | Coadd 7862 | 2024-09-18 13:35:08 | MASTER-Tunka | (19h 18m 10.43s , +46d 10m 42.6s) | C | 60 | 18.1 | Coadd 8024 | 2024-09-18 13:37:51 | MASTER-Tunka | (19h 18m 10.13s , +46d 08m 47.7s) | C | 60 | 18.1 | Coadd 8187 | 2024-09-18 13:40:33 | MASTER-Tunka | (19h 18m 13.05s , +46d 09m 18.0s) | C | 60 | 18.1 | Coadd 8424 | 2024-09-18 13:44:31 | MASTER-Tunka | (19h 18m 09.57s , +46d 11m 00.5s) | C | 60 | 17.9 | Coadd 8585 | 2024-09-18 13:47:11 | MASTER-Tunka | (19h 18m 09.30s , +46d 09m 05.9s) | C | 60 | 18.1 | Coadd 8747 | 2024-09-18 13:49:53 | MASTER-Tunka | (19h 18m 12.35s , +46d 09m 17.2s) | C | 60 | 18.2 | Coadd 8987 | 2024-09-18 13:53:53 | MASTER-Tunka | (19h 18m 09.73s , +46d 11m 20.2s) | C | 60 | 18.0 | Coadd 9150 | 2024-09-18 13:56:37 | MASTER-Tunka | (19h 18m 08.75s , +46d 09m 26.5s) | C | 60 | 17.7 | Coadd 9313 | 2024-09-18 13:59:20 | MASTER-Tunka | (19h 18m 11.73s , +46d 09m 54.4s) | C | 60 | 17.6 | Coadd 9559 | 2024-09-18 14:03:26 | MASTER-Tunka | (19h 18m 08.14s , +46d 11m 40.4s) | C | 60 | 17.4 | Coadd 9724 | 2024-09-18 14:06:11 | MASTER-Tunka | (19h 18m 08.54s , +46d 09m 46.4s) | C | 60 | 17.1 | Coadd 9885 | 2024-09-18 14:08:52 | MASTER-Tunka | (19h 18m 10.74s , +46d 10m 01.5s) | C | 60 | 16.8 | Coadd 10121 | 2024-09-18 14:12:48 | MASTER-Tunka | (19h 18m 08.25s , +46d 11m 59.0s) | C | 60 | 17.2 | Coadd 10282 | 2024-09-18 14:15:28 | MASTER-Tunka | (19h 18m 06.43s , +46d 10m 03.6s) | C | 60 | 17.2 | Coadd 10442 | 2024-09-18 14:18:08 | MASTER-Tunka | (19h 18m 09.63s , +46d 10m 27.6s) | C | 60 | 17.2 | Coadd 10678 | 2024-09-18 14:22:04 | MASTER-Tunka | (19h 18m 07.08s , +46d 12m 16.2s) | C | 60 | 17.3 | Coadd 10837 | 2024-09-18 14:24:44 | MASTER-Tunka | (19h 18m 06.80s , +46d 10m 20.8s) | C | 60 | 17.2 | Coadd 10997 | 2024-09-18 14:27:24 | MASTER-Tunka | (19h 18m 08.71s , +46d 10m 37.6s) | C | 60 | 17.1 | Coadd 11234 | 2024-09-18 14:31:21 | MASTER-Tunka | (19h 18m 05.10s , +46d 12m 31.8s) | C | 60 | 17.1 | Coadd 18777 | 2024-09-18 16:37:03 | MASTER-Tavrida | (19h 17m 32.41s , +46d 05m 00.9s) | C | 60 | 17.2 | 18777 | 2024-09-18 16:37:03 | MASTER-Tavrida | (19h 17m 33.33s , +46d 09m 15.9s) | C | 60 | 17.4 | 19669 | 2024-09-18 16:51:55 | MASTER-Tavrida | (19h 17m 31.56s , +46d 04m 47.0s) | C | 60 | 18.1 | 19669 | 2024-09-18 16:51:55 | MASTER-Tavrida | (19h 17m 33.22s , +46d 08m 14.1s) | C | 60 | 18.4 | 19920 | 2024-09-18 16:56:07 | MASTER-Tavrida | (19h 17m 32.46s , +46d 02m 40.9s) | C | 60 | 18.0 | 19921 | 2024-09-18 16:56:07 | MASTER-Tavrida | (19h 17m 30.82s , +45d 58m 44.6s) | C | 60 | 18.4 | 20774 | 2024-09-18 17:10:21 | MASTER-Tavrida | (19h 17m 33.63s , +46d 03m 39.5s) | C | 60 | 18.1 | 20775 | 2024-09-18 17:10:21 | MASTER-Tavrida | (19h 17m 35.14s , +46d 07m 37.3s) | C | 60 | 18.4 | 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/37548. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35465] EP EP240918a: Global MASTER-Net observations report
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37548 SUBJECT: EP EP240918a: Global MASTER-Net observations report DATE: 24/09/18 17:18:36 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the EP EP240918a ( EP Team et al., GCN 37541) errorbox 151 sec after notice time and 7592 sec after trigger time at 2024-09-18 13:31:09 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 11 deg. The sun altitude is -21.2 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP EP240918a errorbox 11305 sec after notice time and 18746 sec after trigger time at 2024-09-18 16:37:03 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 6 deg. The sun altitude is -9.7 deg. The galactic latitude b = 15 deg., longitude l = 78 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2606210 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 7623 | 2024-09-18 13:31:09 | MASTER-Tunka | (19h 18m 13.42s , +46d 08m 39.1s) | C | 60 | 18.7 | Coadd 7862 | 2024-09-18 13:35:08 | MASTER-Tunka | (19h 18m 10.43s , +46d 10m 42.6s) | C | 60 | 18.1 | Coadd 8024 | 2024-09-18 13:37:51 | MASTER-Tunka | (19h 18m 10.13s , +46d 08m 47.7s) | C | 60 | 18.1 | Coadd 8187 | 2024-09-18 13:40:33 | MASTER-Tunka | (19h 18m 13.05s , +46d 09m 18.0s) | C | 60 | 18.1 | Coadd 8424 | 2024-09-18 13:44:31 | MASTER-Tunka | (19h 18m 09.57s , +46d 11m 00.5s) | C | 60 | 17.9 | Coadd 8585 | 2024-09-18 13:47:11 | MASTER-Tunka | (19h 18m 09.30s , +46d 09m 05.9s) | C | 60 | 18.1 | Coadd 8747 | 2024-09-18 13:49:53 | MASTER-Tunka | (19h 18m 12.35s , +46d 09m 17.2s) | C | 60 | 18.2 | Coadd 8987 | 2024-09-18 13:53:53 | MASTER-Tunka | (19h 18m 09.73s , +46d 11m 20.2s) | C | 60 | 18.0 | Coadd 9150 | 2024-09-18 13:56:37 | MASTER-Tunka | (19h 18m 08.75s , +46d 09m 26.5s) | C | 60 | 17.7 | Coadd 9313 | 2024-09-18 13:59:20 | MASTER-Tunka | (19h 18m 11.73s , +46d 09m 54.4s) | C | 60 | 17.6 | Coadd 9559 | 2024-09-18 14:03:26 | MASTER-Tunka | (19h 18m 08.14s , +46d 11m 40.4s) | C | 60 | 17.4 | Coadd 9724 | 2024-09-18 14:06:11 | MASTER-Tunka | (19h 18m 08.54s , +46d 09m 46.4s) | C | 60 | 17.1 | Coadd 9885 | 2024-09-18 14:08:52 | MASTER-Tunka | (19h 18m 10.74s , +46d 10m 01.5s) | C | 60 | 16.8 | Coadd 10121 | 2024-09-18 14:12:48 | MASTER-Tunka | (19h 18m 08.25s , +46d 11m 59.0s) | C | 60 | 17.2 | Coadd 10282 | 2024-09-18 14:15:28 | MASTER-Tunka | (19h 18m 06.43s , +46d 10m 03.6s) | C | 60 | 17.2 | Coadd 10442 | 2024-09-18 14:18:08 | MASTER-Tunka | (19h 18m 09.63s , +46d 10m 27.6s) | C | 60 | 17.2 | Coadd 10678 | 2024-09-18 14:22:04 | MASTER-Tunka | (19h 18m 07.08s , +46d 12m 16.2s) | C | 60 | 17.3 | Coadd 10837 | 2024-09-18 14:24:44 | MASTER-Tunka | (19h 18m 06.80s , +46d 10m 20.8s) | C | 60 | 17.2 | Coadd 10997 | 2024-09-18 14:27:24 | MASTER-Tunka | (19h 18m 08.71s , +46d 10m 37.6s) | C | 60 | 17.1 | Coadd 11234 | 2024-09-18 14:31:21 | MASTER-Tunka | (19h 18m 05.10s , +46d 12m 31.8s) | C | 60 | 17.1 | Coadd 18777 | 2024-09-18 16:37:03 | MASTER-Tavrida | (19h 17m 32.41s , +46d 05m 00.9s) | C | 60 | 17.2 | 18777 | 2024-09-18 16:37:03 | MASTER-Tavrida | (19h 17m 33.33s , +46d 09m 15.9s) | C | 60 | 17.4 | 19669 | 2024-09-18 16:51:55 | MASTER-Tavrida | (19h 17m 31.56s , +46d 04m 47.0s) | C | 60 | 18.1 | 19669 | 2024-09-18 16:51:55 | MASTER-Tavrida | (19h 17m 33.22s , +46d 08m 14.1s) | C | 60 | 18.4 | 19920 | 2024-09-18 16:56:07 | MASTER-Tavrida | (19h 17m 32.46s , +46d 02m 40.9s) | C | 60 | 18.0 | 19921 | 2024-09-18 16:56:07 | MASTER-Tavrida | (19h 17m 30.82s , +45d 58m 44.6s) | C | 60 | 18.4 | 20774 | 2024-09-18 17:10:21 | MASTER-Tavrida | (19h 17m 33.63s , +46d 03m 39.5s) | C | 60 | 18.1 | 20775 | 2024-09-18 17:10:21 | MASTER-Tavrida | (19h 17m 35.14s , +46d 07m 37.3s) | C | 60 | 18.4 | 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/37548. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35464] EP240918a: JinShan optical upper limits
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37547 SUBJECT: EP240918a: JinShan optical upper limits DATE: 24/09/18 16:46:22 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> S.Y. Fu, X. Liu, S.Q. Jiang, J. An, Z.P. Zhu, D. Xu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration: We observed the field of EP240918a detected by EP/WXT (Zhang et al., GCN 37541), using the 50cm-A/B and 100cm-C telescopes (50A, 50B and 100C) of the JinShan project, located at Altay, Xinjiang, China. Observations started at 13:38:24 UT on 2024-09-18, i.e., 2.23 hr after the EP trigger, and a series of frames were obtained in the Sloan g-, r-, i- and z- bands. No new optical source is detected within the EP/FXT error circle (Zhang et al., GCN 37541), down to the following 5-sigma upper limits: T_mid (UT) | T_mid (hr) | Telescope | filter | U.L. (AB) ---------------------------------------------------- 2024-09-18T13:53:45.0 | 2.49 | 50B | z | 17.1 2024-09-18T13:55:53.5 | 2.52 | 50A | r | 19.3 2024-09-18T14:24:52.5 | 3.00 | 50B | i | 18.2 2024-09-18T14:26:51.0 | 3.04 | 50A | g | 19.2 2024-09-18T15:52:16.8 | 4.46 | 100C | r | 21.2 calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction. We acknowledge the excellent support from X. Yao, S.W. Luo, and Z.K. Feng for enabling these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/37547. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35463] EP240918a: YAHPT Optical Upper Limit
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37546 SUBJECT: EP240918a: YAHPT Optical Upper Limit DATE: 24/09/18 16:00:01 GMT FROM: Tianrui Sun at Purple Mountain Obs,CAS <trsun(a)pmo.ac.cn> Tian-Rui Sun, Jin-Jun Geng, Jian Chen, Yan-Long Hua, Yi-Fang Liang (Purple Mountain Observatory, CAS) and Lei Hu (CMU) report on behalf of the YAHPT team: Following the detection of EP240918a by Einstein Probe (Zhang et al., GCN 37541), we use the Yaoan High Precision Telescope at Yaoan Astronomy Observation Station (Yunnan province, China) to search and follow up. We observed the target position in both Rc and Ic starting from 2024-09-18T13:13:31 with 180s exposure. We did not detect any possible new optical counterpart with an uncertainty of 20 arcsec in the coadded image. UT (start) |5 sigma Upper Limit| Exposure Time | Filter 2024-09-18T13:13:31| 20.3 | 180*5s | Rc 2024-09-18T13:16:34| 19.1 | 180*5s | Ic This non-detection result of the transient is in agreement with the previous circulars (Wang et al., GCN 37544). We used the USNO B1.0 catalogue (R2mag and Imag) as the magnitude reference for calibration. View this GCN Circular online at https://gcn.nasa.gov/circulars/37546. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35462] EP240918a: Optical upper limits with Kinder observations
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37545 SUBJECT: EP240918a: Optical upper limits with Kinder observations DATE: 24/09/18 15:59:55 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> A. K. H. Kong (NTHU), A. Aryan, T.-W. Chen, C.-H. Lai, H.-Y. Hsiao, C.-S. Lin (all NCU), S. Yang (HNAS), S. J. Smartt (Oxford/QUB), A. Sankar. K, Y. J. Yang, W.-J. Hou, C.-C. Ngeow, M.-H. Lee, Y.-C. Pan, H.-C. Lin, J.-K. Guo (all NCU), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, J. Gillanders, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the fast X-ray transient EP240918a (Zhang et al., GCN 37541) using the 40cm SLT at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024arXiv240609270C). The first SLT epoch of observations started at 13:43 UTC on the 18th of September 2024 (MJD = 60571.571), 2.30 hrs after the EP trigger. We utilized the astroalign (Beroiz et al., 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al., 2022, ApJ, 935, 167) packages to align and stack the individual frames. In the stacked frames, we do not detect any evidence of a new uncataloged source within the FXT error circle of 20" reported by Zhang et al. (GCN 37541). Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the photometry on our stacked frame. The details of the observations and measured 3-sigma upper limit (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass SLT | r | 60571.571 | 2.30 hrs | 300 sec * 16 | >20.5 | 1".83 | 1.37 The presented magnitudes are calibrated using the field stars from the Pan-STARRS1 catalog and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.08 mag in the direction of the transient (Schlafly & Finkbeiner 2011). Our result is consistent with Wang et al. (GCN 37544). We thank the Einstein Probe team for useful communication. View this GCN Circular online at https://gcn.nasa.gov/circulars/37545. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 35461] EP240918a: Optical upper limits with Kinder observations
by GCN Circulars 18 Sep '24

18 Sep '24

TITLE: GCN CIRCULAR NUMBER: 37545 SUBJECT: EP240918a: Optical upper limits with Kinder observations DATE: 24/09/18 15:59:55 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> A. K. H. Kong (NTHU), A. Aryan, T.-W. Chen, C.-H. Lai, H.-Y. Hsiao, C.-S. Lin (all NCU), S. Yang (HNAS), S. J. Smartt (Oxford/QUB), A. Sankar. K, Y. J. Yang, W.-J. Hou, C.-C. Ngeow, M.-H. Lee, Y.-C. Pan, H.-C. Lin, J.-K. Guo (all NCU), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, J. Gillanders, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the fast X-ray transient EP240918a (Zhang et al., GCN 37541) using the 40cm SLT at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024arXiv240609270C). The first SLT epoch of observations started at 13:43 UTC on the 18th of September 2024 (MJD = 60571.571), 2.30 hrs after the EP trigger. We utilized the astroalign (Beroiz et al., 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al., 2022, ApJ, 935, 167) packages to align and stack the individual frames. In the stacked frames, we do not detect any evidence of a new uncataloged source within the FXT error circle of 20" reported by Zhang et al. (GCN 37541). Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the photometry on our stacked frame. The details of the observations and measured 3-sigma upper limit (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass SLT | r | 60571.571 | 2.30 hrs | 300 sec * 16 | >20.5 | 1".83 | 1.37 The presented magnitudes are calibrated using the field stars from the Pan-STARRS1 catalog and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.08 mag in the direction of the transient (Schlafly & Finkbeiner 2011). Our result is consistent with Wang et al. (GCN 37544). We thank the Einstein Probe team for useful communication. View this GCN Circular online at https://gcn.nasa.gov/circulars/37545. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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