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

[vsnet-grb-info 34875] EP240801a: NOT optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37008 SUBJECT: EP240801a: NOT optical observations DATE: 24/08/02 00:33:18 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> D. B. Malesani (DAWN/NBI and Radboud Univ.), J. Quirola-Vásquez (Radboud Univ.), J. van Dalen (Radboud Univ.), P. G. Jonker (Radboud Univ), A. J. Levan (Radboud Univ. & Warwick Univ.), F. E. Bauer (PUC), M. E. Ravasio (Radboud Univ.), D. Mata Sanchez (IAC), M. A. P. Torres (IAC), on behalf of a larger collaboration, D. Xu (NAOC), Z. P. Zhu (NAOC): We report on optical follow-up observations of the Einstein Probe fast X-ray transient EP240801a (Zhou et al., GCN 36997). We observed the optical counterpart of EP240801a (Fu et al., GCN 36998) using the ALFOSC instrument mounted on the Nordic Optical Telescope (NOT), with an exposure of 3x300 s in the SDSS-r band. Observations started on 2024-08-01T22:37:41 UT, that is ~13.56 hours after the EP trigger, at an airmass of ~2. An object is detected at a position consistent with the one reported by Fu et al. (GCN 36998), for which we measure a preliminary magnitude r = 21.67 +- 0.04 mag, calibrated against nearby Pan-STARRS sources. We thank the Nordic Optical Telescope team, in particular Alba Casasbuenas Corral, for making these observations possible. View this GCN Circular online at https://gcn.nasa.gov/circulars/37008. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34874] EP240801a: follow-up observation with LCOGT
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37007 SUBJECT: EP240801a: follow-up observation with LCOGT DATE: 24/08/01 23:07:03 GMT FROM: Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf(a)iac.es> I. Pérez-Fournon, F. Poidevin, D. S. Aguado, J. A. Acosta-Pulido, A. López-Oramas, D. Nespral (IAC and ULL), and F. Acero (CEA Saclay and IAC) We report on optical follow-up observations of the Einstein Probe fast X-ray transient EP240801a (Zhou et al. GCN 36997). We observed the field of EP240801a using one of the 1-meter telescopes at the Las Cumbres Observatory node located at Siding Spring Observatory (Australia), with a single 300-sec exposure in SDSS-g band starting on 2024-08-01T16:45:15 (UTC), ~ 7.65 hours after the EP trigger, at an airmass of ~ 2.3. We detect the optical counterpart at the position reported by Fu et al. (GCN 36998) with g = 21.43 +/- 0.2 mag, calibrated with PanSTARRS and not corrected for Galactic extinction. Detections of the optical counterpart have also been reported by Li et al. (GCN 36999), Zheng et al.(GCN 37000), Aryan et al. (GCN 37002), and An et al.(GCN 37004). This work makes use of observations from the Las Cumbres Observatory global telescope network (program IAC2024B-004). View this GCN Circular online at https://gcn.nasa.gov/circulars/37007. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34873] Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37006 SUBJECT: Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB DATE: 24/08/01 22:54:08 GMT FROM: sumanbala2210(a)gmail.com S. Bala (USRA) reports on behalf of the Fermi-GBM Team: AstroSat CZTI detected GRB 240801B at 2024-08-01 04:39:49.5 UTC (GCN 36996). There was a Fermi-GBM onboard trigger (744179961 / 240801194) due to a solar flare around 2024-08-01 04:39:16.781 UTC. Due to the extreme solar flare flux we can not confirm the presence of any GRB. The on-ground calculated location of the peak identified by AstroSat, using the Fermi GBM trigger data, is RA = 124.41, Dec = 13.21 (J2000 degrees, equivalent to J2000 8h 17m, 13d 12') with a statistical uncertainty of 1 degrees. The localization is found to be close to the position of the Sun (RA = 131.531, Dec = 17.97). As the source is highly contaminated by the solar flare flux, the background and the localization is uncertain. The angle from the Fermi LAT boresight is 71 degrees. View this GCN Circular online at https://gcn.nasa.gov/circulars/37006. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34872] GRB 240730A: Swift-BAT refined analysis
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37005 SUBJECT: GRB 240730A: Swift-BAT refined analysis DATE: 24/08/01 19:55:22 GMT FROM: Michael Moss at NASA GSFC <mikejmoss3(a)gmail.com> D. Sadaula (GSFC/UMBC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240730A (trigger #1245636) (Cenko, et al., GCN Circ. 36976). The BAT ground-calculated position is RA, Dec = 37.841, 59.045 deg which is RA(J2000) = 02h 31m 21.9s Dec(J2000) = +59d 02' 43.5" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%. The BAT mask-weighted light curve displays two spectrally soft peaks. The T90 (15-350 keV) is 50.13 +- 7.60 sec (estimated error including systematics). The time-averaged spectrum from T-6.06 to T+53.43 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.50 +- 0.19. The fluence in the 15-150 keV band is 6.8 +- 0.9 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+5.80 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1245636 The long duration and proximity to the Galactic plane raised the initial possibility that this was a Galactic transient. However, its subsequent behavior, including a lack of later BAT detections, is consistent with a GRB, making the Galactic transient interpretation less likely. View this GCN Circular online at https://gcn.nasa.gov/circulars/37005. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34871] EP240801a: GSP follow-up observations of the candidate counterpart
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37004 SUBJECT: EP240801a: GSP follow-up observations of the candidate counterpart DATE: 24/08/01 18:47:30 GMT FROM: Wenxiong Li <liwenxiong1992(a)gmail.com> J. An, D. Xu, W. X. Li, S. J. Xue (NAOC), M. Andrews, J. Farrah, D. A. Howell, M. Newsome, E. Padilla Gonzalez, C. McCully, and G. Terreran (Las Cumbres Observatory), on behalf of a larger collaboration, report: Following the detection of the fast X-ray transient EP240801a by the Einstein Probe (Zhou et al., GCN 36997), we initiated observations of the fast X-ray transient location starting on Aug 1 at 10:26 UT (~1.3 hours after the trigger) in the r band. These observations were conducted using the 1-meter telescope at the Las Cumbres Observatory node located at McDonald Observatory in the USA. The optical counterpart reported by Fu et al. (GCN 36998), Li et al. (GCN 36999) and Zheng et al. (GCN 37000) was detected with r = 20.54+/-0.08 mag. These observations were taken as part of the Global Supernova Project. View this GCN Circular online at https://gcn.nasa.gov/circulars/37004. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34870] Fermi trigger No 744204856: Global MASTER-Net observations report
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37003 SUBJECT: Fermi trigger No 744204856: Global MASTER-Net observations report DATE: 24/08/01 18:30:42 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-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 Fermi GRB240801.48 (trigger No 744204856,08h 38m 07.92s , +19d 25m 01.2s, R=35.17) errorbox 23511 sec after notice time and 23543 sec after trigger time at 2024-08-01 18:06:35 UT, with upper limit up to 13.9 mag. Observations started at twilight. The observations began at zenith distance = 70 deg. The sun altitude is -10.0 deg. The galactic latitude b = 32 deg., longitude l = 206 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2548010 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 23574 | 2024-08-01 18:06:35 | MASTER-Tavrida | (10h 38m 44.18s , +36d 00m 46.7s) | C | 60 | 13.9 | 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/37003. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34869] EP240708a: Kinder follow-up observations of the candidate counterpart
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37002 SUBJECT: EP240708a: Kinder follow-up observations of the candidate counterpart DATE: 24/08/01 18:22:32 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> A. Aryan (NCU), A. K. H. Kong (NTHU), H.-Y. Hsiao, W.-J. Hou, T.-W. Chen, Y. J. Yang (all NCU), S. Yang (HNAS), J. Gillanders (Oxford), C.-C. Ngeow, C.-S. Lin, C.-H. Lai, A. Sankar. K, M.-H. Lee, Y.-C. Pan, H.-C. Lin, J.-K. Guo (all NCU), S. J. Smartt (Oxford/QUB), H.-W. Lin (UMich), G. H. Sun, Z. N. Wang (both HNAS), H. F. Stevance, S. Srivastav, 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 EP240801a (Zhou et al., GCN 36997) 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 13:45 UTC on the 1st of August 2024 (MJD = 60523.573), 4.66 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 clearly detect the optical counterpart reported by Fu et al., (GCN 36998), and confirmed by Li et al. (GCN 36999) and Zheng et al. (GCN 37000). Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the PSF photometry on our stacked frame. The details of the observations and measured photometry (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass SLT | r | 60523.573 | 4.66 hrs | 300 sec * 12 | 20.9 +/- 0.3 | 1".83 | 1.63 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) = 0.10 mag in the direction of the transient (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/37002. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34868] EP240708a: Kinder follow-up observations of the candidate counterpart
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37001 SUBJECT: EP240708a: Kinder follow-up observations of the candidate counterpart DATE: 24/08/01 18:22:32 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> A. Aryan (NCU), A. K. H. Kong (NTHU), H.-Y. Hsiao, W.-J. Hou, T.-W. Chen, Y. J. Yang (all NCU), S. Yang (HNAS), J. Gillanders (Oxford), C.-C. Ngeow, C.-S. Lin, C.-H. Lai, A. Sankar. K, M.-H. Lee, Y.-C. Pan, H.-C. Lin, J.-K. Guo (all NCU), S. J. Smartt (Oxford/QUB), H.-W. Lin (UMich), G. H. Sun, Z. N. Wang (both HNAS), H. F. Stevance, S. Srivastav, 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 EP240801a (Zhou et al., GCN 36997) 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 13:45 UTC on the 1st of August 2024 (MJD = 60523.573), 4.66 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 clearly detect the optical counterpart reported by Fu et al., (GCN 36998), and confirmed by Li et al. (GCN 36999) and Zheng et al. (GCN 37000). Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the PSF photometry on our stacked frame. The details of the observations and measured photometry (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass SLT | r | 60523.573 | 4.66 hrs | 300 sec * 12 | 20.9 +/- 0.3 | 1".83 | 1.63 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) = 0.10 mag in the direction of the transient (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/37001. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34867] EP240801a: KAIT optical counterpart observations
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37000 SUBJECT: EP240801a: KAIT optical counterpart observations DATE: 24/08/01 17:41:44 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, automatically responded to the fast X-ray transient EP240801a from the Einstein Probe (Zhou et al. GCNC 36997) starting at 09:27 UT, ~0.41 hours after the trigger. A set of clear (roughly R) filter images were obtained. The optical counterpart reported by Fu et al. (GCN 36998) and Li et al. (GCN 36999) was clearly detected in our coadded images. The preliminary photometry results are shown below calibrated to the PS1 catalog: Tmid-T0(hr) exp(s) Mag err 0.41 6x20s 19.86 0.07 0.54 6x40s 20.02 0.05 0.73 5x60s 20.05 0.04 0.93 5x60s 20.11 0.07 1.54 7x60s 20.17 0.06 1.93 9x60s 20.09 0.06 View this GCN Circular online at https://gcn.nasa.gov/circulars/37000. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34866] EP240801a: GMG observation
by GCN Circulars 01 Aug '24

01 Aug '24

TITLE: GCN CIRCULAR NUMBER: 36999 SUBJECT: EP240801a: GMG observation DATE: 24/08/01 17:06:44 GMT FROM: Rui-Zhi Li at Yunnan Observatories, CAS <liruizhi(a)ynao.ac.cn> R.-Z. Li, B.-T. Wang, J. Mao, X.-L. Zhang and J.-M. Bai (YNAO, CAS) report: We observed the field of EP240801a (Zhou et al., GCN 36997, T0 at 2024-08-01T09:06:03) using the GMG-2.4m telescope at the Lijiang Observatory. The observation began at 2024-08-01T16:19:22, about 7.22 hours after the trigger. The optical counterpart of EP240801a, not visible in the Pan-STARRS1 r-band image, was marginally detected at the coordinates (J2000): RA = 23h00m39.02s DEC = +32d35m37.2s , with a positional uncertainty of 0.5" or better. The position is consistent with TRT observation (GCN 36998). The preliminary analysis results are shown as follows: +---------------+------------+----------+--------------+--------------+ | Tmid-T0 [h] | Exp. [s] | Filter | Mag | 5-sigma UL | +===============+============+==========+==============+==============+ | 7.39 | 1200 | R | 21.21 ± 0.12 | 21.9 | +---------------+------------+----------+--------------+--------------+ The given magnitudes are derived based on calibration against Pan-STARRS1 field stars, and are not corrected for the expected Galactic foreground extinction, corresponding to a reddening of E(B-V) = 0.092 mag in the direction of the optical counterpart (Schlafly & Finkbeiner 2011). We note that this optical counterpart has become fainter compared to the TRT observation (R = 20.32 ± 0.16 mag, GCN 36998). View this GCN Circular online at https://gcn.nasa.gov/circulars/36999. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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