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

[vsnet-grb-info 34885] EP240801a: further SAO RAS optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37017 SUBJECT: EP240801a: further SAO RAS optical observations DATE: 24/08/02 23:12:07 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS) report on behalf of the GRB follow-up team. We observed the field of the fast X-ray transient EP240801a (Zhou et al., GCN 36997) with the SAO RAS 1-meter telescope Zeiss-1000 equipped with the CCD-photometer. We obtained 9 x 300 sec frames in Rc band on 2024-08-02T20:14:00 -- 2024-08-02T22:09:01 (UTC), t_mid - T0 = 1.5038 days. The OT (Fu et al., GCN 36998; Li et al., GCN 36999; Zheng et al., GCN 37000; Aryan et al., GCN 37002; An et al., GCN 37004; Perez-Fournon et al., GCN 37007; Malesani et al., GCN 37008; Zhu et al., GCN 37010; Quirola-Vasquez et al., GCN 37013; Moretti et al., GCN 37014; Turpin et al., GCN 37015; Pankov et al., GCN 37016) is clearly detected in the stacked frame with the brightness of R = 22.17 +/- 0.15, calibrated against nearby Pan-STARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/37017. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34884] EP240801a: optical observations at CrAO and AbAO
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37016 SUBJECT: EP240801a: optical observations at CrAO and AbAO DATE: 24/08/02 15:06:19 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO),R. Ya. Inasaridze (AbAO) report on behalf of GRB-IKI-FuN: We observed the field of EP240801a (Zhou et al, GCN 36997) with ZTSh 2.6 m telescope of CrAO, and AS-32 0.7 m telescope of AbAO. The observations were carried out in moderate conditions with seeing of about 2.0 arcsec. We took a series of images in the R-filter, starting on 2024-08-01 20:28 (UT) at CrAO (i.e. 11 hours after the EP trigger). We clearly detect the optical counterpart (Fu et al, GCN 36998; Li et al, GCN 36999; Zheng et al, GCN 37000; Aryan et al, GCN 37002; An et al, GCN 37004; Pérez-Fournon et al, GCN 37007; Malesani et al, GCN 37008; Zhu et al, GCN 37010; Moskvitin & Spiridonova, GCN 37012; Quirola-Vásquez et al, GCN 37013; Moretti et al., GCN 37014; Turpin et al., GCN 37015) in images from CrAO, while obtaining upper limit at AbAO. Preliminary photometry is given below: Date UT start t-T0 Exp. Filter OT Err. UL(3 sigma) Scope (mid, days) (s) 2024-08-01 20:28:07 0.50492 15x120 R 21.3 0.1 23.7 ZTSh 2024-08-01 20:32:01 0.50970 44x60 R n/d n/d 21.0 AS-32 The magnitudes were calibrated using nearby stars from USNO-B1.0 catalog (R2 mags) and are not corrected for the Galactic extinction A(R) = 0.237 mag (S&F 2011) towards the EP source. The obtained results are consistent with observations published earlier. View this GCN Circular online at https://gcn.nasa.gov/circulars/37016. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34883] EP240801a: GRANDMA and Kilonova-Catcher optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37015 SUBJECT: EP240801a: GRANDMA and Kilonova-Catcher optical observations DATE: 24/08/02 14:53:29 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> D. Turpin (CEA-Saclay/Irfu), S. Aghayeva (Shamakhy Obs.), Z. Vidadi (Shamakhy Obs.), N. Kochiashvili (Abastumani Obs.), S. Antier (OCA), S. Karpov (FZU), M. Coughlin (UMN), C. Andrade (UMN), I. Tosta e Melo (UniCT-DFA), P. Hello, N. Leroy (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), M. Masek (FZU), M. Prouza (FZU), M. Freeberg (KNC), S. Leonini (KNC, Montarrenti Obs.), Y. Rajabov (UBAI), M. Serrau (KNC) on behalf of the GRANDMA and Kilonova-Catcher collaborations: We performed observations with GRANDMA and its citizen science project Kilonova-catcher (KNC) on the X-ray transient EP240801a detected by Einstein Probe (EP) WXT on T0 = 2024-08-01T09:06:03 (Zhou et al., GCN 36997). Our observations were made from 2024-08-01T20:32:01 to 2024-08-02T08:49:33 UTC, starting 11.4 hours after the EP trigger. In most of our images, we did not detect the optical counterpart identified by several other follow-up observations (Fu et al., GCN 36998; Li et al. GCN 36999; Zheng et al. 36999; Aryan et al., GCN 37002; An et al., GCN 37004; Pérez-Fournon et al. GCN 37007; Malesani et al., GCN 37008, Zhu et al. GCN 37010, Moskvitin et al. GCN 37012, Quirola-Vásquez et al. GCN 37013; Moretti et al., GCN 37014). Our 5 sigma upper limits are consistent with the reported detections. In addition, we note a marginal detection in one of our stacked frame taken at a midtime ~15.7h after the EP/WXT trigger time with the following magnitude G = 22.1 +/- 0.5. All our observations and upper limits (5 sigma C.L.) can be found here: +--------------+------------+-------+-----------+---------------------+ | MJD | T-T0 (hrs) |Filter | Mag (AB) | Instrument | +==============+============+===================+=====================+ | 60523.855567 | 11.43 | sdssr |20.7 (U.L) | AbAO-T70 | +--------------+------------+-------+-----------+---------------------+ | 60523.951979 | 13.74 | R |20.2 (U.L.)| UBAI-NT60 | +--------------+------------+-------+-----------+---------------------+ | 60523.953785 | 13.79 | R |19.3 (U.L.)| KNC-Montarrenti Obs.| +--------------+------------+-------+-----------+---------------------+ | 60523.997921 | 14.85 | R |18.4 (U.L.)| FRAM-CTA-N | +--------------+------------+-------+-----------+---------------------+ | 60524.032112 | 15.67 | Gaia G|22.1+/-0.5 | KNC-Dauban Meade 12"| +--------------+------------+-------+-----------+---------------------+ | 60524.055914 | 16.24 | sdssr |21.0 (U.L.)| KNC-CDK17 | +--------------+------------+-------+-----------+---------------------+ | 60524.279711 | 21.61 | sdssr |21.2 (U.L.)| KNC-T160FL | +--------------+------------+-------+-----------+---------------------+ Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 Synphot catalog, images taken with Sloan filters were calibrated using the Pan-STARRS DR1 Catalog while images taken with Gaia G filters were calibrated using the Gaia eDR3 catalog. All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022). We use the Skyportal application (skyportal.io) to monitor our observational campaign. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). View this GCN Circular online at https://gcn.nasa.gov/circulars/37015. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34882] EP240801a: Leavitt Observatory optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37014 SUBJECT: EP240801a: Leavitt Observatory optical observations DATE: 24/08/02 13:20:21 GMT FROM: leavittob(a)gmail.com L. Moretti and E. Pavoni (Leavitt Observatory, Italy), in a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report: We imaged the field of the X-ray transient EP240801a detected by Einstein Probe (EP, Zhou et al., GCN 36997; Fu et al., GCN 36998; Li et. al. GCN 36999; Zheng et al, GCN 37000; Aryan et al. GCN 37002; An et al., GCN 37004; Pérez-Fournon et al., GCN 37007; Malesani et al., GCN 37008; Zhu et al., GCN 37010; Moskvitin et al., GCN 37012), with the telescope of Leavitt Observatory, Italy. Member of: UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili, GRB section. ATA - Associazione Tuscolana di Astronomia. The transient event started at 2024-08-01 09:06:03 (UTC). Our observations started about 11 hours after the EP trigger, with a RC telescope D=250 mm F/D=8. Weather conditions were good. We co-added 12 images of 120 sec each. All images are unfiltered, calibrated with masterdark and masterflat. An uncatalogued optical transient (OT) is marginally detected in the stacked image at coordinates: R.A. (J2000) = 23:00:39.02 Dec. (J2000) = +32:35:37.2 with the following photometry: Date UT Middle: 2024-08-01 20:48:27 UTC CR-mag 21.4 +/- 0.2 Given the low S/N for the OT, we cannot completely rule out it being due to background fluctuation. Magnitudes were estimated with the Pan-STARRS cat. and converted using Lupton (2005) equations. No corrected for galactic dust extinction. Reference: https://leavittobservatory.altervista.org The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/37014. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34881] EP240801a: GTC spectroscopy and absorption redshift
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37013 SUBJECT: EP240801a: GTC spectroscopy and absorption redshift DATE: 24/08/02 10:44:40 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> J. Quirola-Vásquez (Radboud Univ.), J. van Dalen (Radboud Univ.), D. B. Malesani (DAWN/NBI and 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), report on behalf of a larger collaboration: We observed the optical counterpart of EP240801a (Zhou et al., GCN 36997; Fu et al., GCN 36998) using the 10.4 m GTC located in La Palma, Canary Islands. Observations started on 2024 Aug 2.169 UT (0.79 days after the EP trigger), consisted of 4 exposures of 1200 s each, and were carried out using grism R1000R, which covers the wavelength range 5100-10000 AA. The counterpart magnitude was r = 21.98 +- 0.05 (AB) as measured in a 30-s acquisition image, calibrated against nearby Pan-STARRS sources. Continuum is well detected over the entire wavelength range. Several absorption lines are visible, which we interpret as due to Mg II and Fe II at a common redshift z = 1.673, which we suggest to be the likely redshift of EP240801a. We acknowledge excellent support from the GTC staff, in particular Stefan Geier and Antonio Luis Cabrera Lavers. View this GCN Circular online at https://gcn.nasa.gov/circulars/37013. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34880] EP240801a: SAO RAS optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37012 SUBJECT: EP240801a: SAO RAS optical observations DATE: 24/08/02 10:06:40 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS) report on behalf of the GRB follow-up team. We observed the field of the fast X-ray transient EP240801a (Zhou et al., GCN 36997) with the SAO RAS 1-meter telescope Zeiss-1000 equipped with the CCD-photometer. We obtained 5 x 300 sec frames in Rc band on 2024-08-01T23:55:51 -- 2024-08-02T00:54:48 (UTC), t_mid - T0 = 15.32 hours. The OT (Fu et al., GCN 36998; Li et al., GCN 36999; Zheng et al., GCN 37000; Aryan et al., GCN 37002; An et al., GCN 37004; Perez-Fournon et al., GCN 37007; Malesani et al., GCN 37008; Zhu et al., GCN 37010) is clearly detected in the stacked frame with the brightness of R = 21.7 +/- 0.1, calibrated against nearby Pan-STARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/37012. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34879] GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37011 SUBJECT: GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare DATE: 24/08/02 03:09:48 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> G. Parwani (IITB), U. Pathak (IITB), D. Saraogi (IITB), G. Waratkar (IITB), and V. Bhalerao (IITB) report on behalf of the AstroSat CZTI collaboration: We undertook a detailed analysis of GRB 240801B (Dasgupta et al., GCN Circ. 36996) with the AstroSat/CZTI localization framework (Saraogi et al., 2024, MNRAS, 530, 2; doi:10.1093/mnras/stae435). Our recovered sky localization from this framework is consistent with the location of the Sun. We thus classify this trigger as a likely solar flare, consistent with the classification by Fermi/GBM (S. Bala, GCN Circ. 37006). CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. View this GCN Circular online at https://gcn.nasa.gov/circulars/37011. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34878] EP240801a: JinShan optical observations
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37010 SUBJECT: EP240801a: JinShan optical observations DATE: 24/08/02 02:38:31 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> Z.P. Zhu, X. Liu, J. An, S.Y. Fu, S.Q. Jiang, L.B. He, D. Xu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration: We observed the field of EP240801a detected by EP/WXT (Zhou et al., GCN 36997), using the JinShan 100cm-C telescope (100C) located at Altay, Xinjiang, China. The observation started at 17:17:48 UT on 2024-08-01, ~ 8.20 hr after the EP/WXT trigger and ended at 22:06:04 UT the same night. A series of exposures were obtained in the Sloan g-, r-, i-, and z- filters. The previously reported optical counterpart by TRT (Fu et al. GCN 36998) has decayed to r = 21.44 +/- 0.06 at 9.63 hr after EP/WXT trigger, calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction. The optical counterpart has also been reported by GMG (Li et al., GCN 36999), KAIT (Zheng et al., GCN 37000), Kinder (Aryan et al., GCN 37002), LCO (An et al., GCN 37004; Pérez-Fournon et al., GCN 37007), and NOT (Malesani et al., GCN 37008). We acknowledge the excellent support from S.W. Luo, M.M. Yang, Z.K. Feng, Q.C. Zhao and L.F. Huo for enabling these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/37010. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34877] GRB 240727C: SVOM/GRM observation
by GCN Circulars 02 Aug '24

02 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37009 SUBJECT: GRB 240727C: SVOM/GRM observation DATE: 24/08/02 00:55:50 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Yong-Wei Dong, Jiang-Tao Liu, Shi-Jie Zheng, Jian-Chao Sun, Wen-Jun tan, Jiang He, Min Gao, Hao-Xuan Guo, Yue Huang, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Wen-Long Zhang, Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Patrick Maeght (LUPM), Frédéric Piron (LUPM), Jingwei Wang (IAP) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), JeanLuc Attéia (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV) report on behalf of the SVOM team: During the commissioning phase, the SVOM/GRM was triggered in-flight by a long GRB 240727C at 2024-07-27T17:30:09 UT (T0), which also triggered AstroSat (GCN 36957) and GRBAlpha (GCN 36979). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single pulse with a duration of about 10 s. The GRM light curve can be found here: https://www.bursthub.cn/admin/static/svgrb240727C.png At the time of this burst the ECLAIRs trigger was active, but no uncatalogued point source could be found inside the ECLAIRs field of view. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/37009. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34876] 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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