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

[vsnet-grb-info 34675] EP240703a: Liverpool Telescope optical follow-up observations
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36821 SUBJECT: EP240703a: Liverpool Telescope optical follow-up observations DATE: 24/07/04 17:53:09 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek and D. A. Perley (LJMU) report: We observed the field of the X-ray transient and probable gamma-ray burst EP240703a (Wang et al., GCN 36807; Frederiks et al., GCN 36809) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 5x180s exposures with the SDSS-I filter between 2024-07-04 02:27:40 UT and 2024-07-04 02:45:02 UT, approximately 1.1 days after the transient. The limiting magnitude of the stacked image is i > 21.9 mag (AB) for a three-sigma detection limit, with mid-observation time being 2024-07-04 02:34:51 UT. No new sources were identified within the 90% confidence 3 arcmin error circle compared to the Pan-STARRS catalogue. Additionally, no source was detected at the TRT candidate afterglow position (An et al., GCN 36815), now thought to be a probable cosmic ray (An et al., GCN 36820). View this GCN Circular online at https://gcn.nasa.gov/circulars/36821. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34674] EP240703a/GRB 240703A: TRT optical candidate likely not real
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36820 SUBJECT: EP240703a/GRB 240703A: TRT optical candidate likely not real DATE: 24/07/04 10:42:33 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), S.Q. Jiang, X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration: Regarding our previously reported afterglow candidate of EP240703a/GRB 240703A (An et al., GCN 36815), we have checked the five 360 s R-band TRT images one by one. First, the candidate is only present in one of the five images, and not in the other four images. Second, it looks sharper than its neighboring sources, although it does cover multiple pixels in the image. We thus re-did cosmic ray removal with a revised script, and this time the candidate basically disappeared while its neighboring sources were almost unaffected by the same cosmic ray removal process. We thus conclude that the candidate is very likely not real. View this GCN Circular online at https://gcn.nasa.gov/circulars/36820. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34673] EP240703a: Kinder optical follow-up observations
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36819 SUBJECT: EP240703a: Kinder optical follow-up observations DATE: 24/07/04 10:31:37 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> A. Aryan (NCUIA), S. Yang (HNAS), T.-W. Chen, Y.-J. Yang, C.-S. Lin, M.-H. Lee, Y.-C. Pan, H.-Y. Hsiao, W.-J. Hou, C.-C. Ngeow, C.-H. Lai, A. Sankar.K, H.-C. Lin, J.-K. Guo (all NCUIA), S. J. Smartt (Oxford/QUB), H. F. Stevance, S. Srivastav, J. Gillanders, L. Rhodes (all Oxford), M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (IfA, University of Hawaii) report: We observed the field of the fast X-ray transient EP240703a (Wang et al., GCN 36807) using the One-meter Telescope (LOT) at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024arXiv240609270C). The first LOT epoch of observations started at 12:48 UT on 03rd of July 2024 (MJD = 60494.540), 12.32 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. We subtracted the stacked images with the Pan-STARRS1 template image using hotpants (Becker A., 2015, ascl.soft. ascl:1504.004). We do not detect the presence of the proposed optical transient source at R.A. = 18:15:03.89 and Dec. = -09:42:02.96, as reported by An et al., GCN 36815, in the difference and stacked images. Our observations were 1.58 hours before those of the TRT observations and reach 2 magnitudes deeper. However, we detect a slight enhancement in the brightness of the eclipsing binary, ZTF J181510.36-094110.1 (Chen et al. 2020, ApJS, 249, 18) in the difference image at R.A. = 18:15:10.36 and Dec. = -09:41:10.1, which is close to the reported coordinate of EP240703a being only 0.66 arcmin away. Morever, we utilized the python based package, AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the PSF photometry on our stacked frame. The current magnitudes of the eclipsing binary in our stacked frame are r = 19.02 +/- 0.04 mag and i = 18.18 +/- 0.05 mag. Besides ZTF J181510.36-094110.1, we do not detect any new optical source in the reference and stacked frames. The details of the observations and measured 3-sigma upper limit are as follow: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass LOT | r | 60494.540 | 12.32 hrs | 300 sec * 6 | > 22.3 | 1".48 | 1.47 LOT | i | 60494.598 | 13.72 hrs | 300 sec * 6 | > 21.8 | 1".34| 1.22 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) = 1.225 mag in the direction of the burst (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/36819. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34672] EP240703a: Kinder optical follow-up observations
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36819 SUBJECT: EP240703a: Kinder optical follow-up observations DATE: 24/07/04 10:31:37 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> A. Aryan (NCUIA), S. Yang (HNAS), T.-W. Chen, Y.-J. Yang, C.-S. Lin, M.-H. Lee, Y.-C. Pan, H.-Y. Hsiao, W.-J. Hou, C.-C. Ngeow, C.-H. Lai, A. Sankar.K, H.-C. Lin, J.-K. Guo (all NCUIA), S. J. Smartt (Oxford/QUB), H. F. Stevance, S. Srivastav, J. Gillanders, L. Rhodes (all Oxford), M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (IfA, University of Hawaii) report: We observed the field of the fast X-ray transient EP240703a (Wang et al., GCN 36807) using the One-meter Telescope (LOT) at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024arXiv240609270C). The first LOT epoch of observations started at 12:48 UT on 03rd of July 2024 (MJD = 60494.540), 12.32 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. We subtracted the stacked images with the Pan-STARRS1 template image using hotpants (Becker A., 2015, ascl.soft. ascl:1504.004). We do not detect the presence of the proposed optical transient source at R.A. = 18:15:03.89 and Dec. = -09:42:02.96, as reported by An et al., GCN 36815, in the difference and stacked images. Our observations were 1.58 hours before those of the TRT observations and reach 2 magnitudes deeper. However, we detect a slight enhancement in the brightness of the eclipsing binary, ZTF J181510.36-094110.1 (Chen et al. 2020, ApJS, 249, 18) in the difference image at R.A. = 18:15:10.36 and Dec. = -09:41:10.1, which is close to the reported coordinate of EP240703a being only 0.66 arcmin away. Morever, we utilized the python based package, AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the PSF photometry on our stacked frame. The current magnitudes of the eclipsing binary in our stacked frame are r = 19.02 +/- 0.04 mag and i = 18.18 +/- 0.05 mag. Besides ZTF J181510.36-094110.1, we do not detect any new optical source in the reference and stacked frames. The details of the observations and measured 3-sigma upper limit are as follow: Telescope | Filter | MJD (start) | t-t0 | Exposure | Magnitude | avg. Seeing | med. Airmass LOT | r | 60494.540 | 12.32 hrs | 300 sec * 6 | > 22.3 | 1".48 | 1.47 LOT | i | 60494.598 | 13.72 hrs | 300 sec * 6 | > 21.8 | 1".34| 1.22 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) = 1.225 mag in the direction of the burst (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/36819. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34671] EP240703c: EP-WXT detection of an X-ray transient
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36818 SUBJECT: EP240703c: EP-WXT detection of an X-ray transient DATE: 24/07/04 07:01:58 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. J. Zhang (THU), M. J. Liu, S. Q. Jiang, H. W. Pan, C. C. Jin, Z. X. Ling, W. Yuan, Y. Liu, C. Zhang, W. Chen, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, D. Y. Li, H. Y. Liu, Z. Z. Lv, T. Y. Lian, X. Mao, X. Pan, H. Sun, W. X. Wang, Y. L. Wang, S. X. Wen, Q. Y. Wu, X. P. Xu, Y. F. Xu, H. N. Yang, M. Zhang, W. D. Zhang, W. J. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Y. Chen, S. M. Jia, S. N. Zhang (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) on behalf of the Einstein Probe team We report on the detection of an X-ray transient EP240703c at 2024-07-03T18:15:00 (UTC) by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission during a calibration observation. The position of the source is R.A. = 289.264 deg, DEC = -30.325 deg (J2000) with an uncertainty of 3 arcmin (radius, 90% C.L. statistical and systematic). The source lasted for over 1 ks with multipeak structure in its lightcurve. The average 0.5-4 keV spectrum can be fitted with an absorbed power law (with the column density fixed at the Galactic value of 8 x 10^20 cm^-2) with a photon index of 1.3(-0.5/+0.5). The unabsorbed flux is 2.5(-0.8/+0.8) x 10^-10 erg/s/cm^2 in the 0.5-4 keV band. The 90 per cent uncertainties are given for the above parameters. Within the error circle of the WXT position, there is a previous X-ray observation of a high proper motion star LP 924-17 with a flux of 4.6 x 10^-13 erg/cm2/s in the 0.3-10 keV range. Based on the light curve and spectrum of the X-ray transient, we tend to consider that the source is not a stellar flare, although the possibility cannot be ruled out. We have proposed a Swift target of opportunity observation. Further follow-up observations are encouraged to identify the nature of this X-ray transient. The above observation was made with the WXT instrument during the commissioning phase of EP. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/36818. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34670] LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
by GCN Circulars 04 Jul '24

04 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36817 SUBJECT: LIGO/Virgo/KAGRA S240703ad: Updated Sky localization DATE: 24/07/04 02:26:41 GMT FROM: Aditya Vijaykumar <aditya.vijaykumar(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) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240703ad (GCN Circular 36816). 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/S240703ad For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 3785 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1894 +/- 679 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/36817. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34669] LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
by GCN Circulars 03 Jul '24

03 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36816 SUBJECT: LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate DATE: 24/07/03 19:51:51 GMT FROM: andrei.danilin(a)LIGO.ORG The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S240703ad during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-07-03 19:13:55.283 UTC (GPS time: 1404069253.283). The candidate was found by the GstLAL [1] analysis pipeline. S240703ad is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.2e-13 Hz, or about one in 1e5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240703ad 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%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] 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 [3], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], 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 11463 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2724 +/- 923 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] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/36816. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34668] EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
by GCN Circulars 03 Jul '24

03 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36815 SUBJECT: EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate DATE: 24/07/03 18:28:56 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> J. An, S.Q. Jiang (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration: We observed the field of the X-ray transient, EP240703a, detected by EP/WXT (Wang et al., GCN 36807), and also by Konus-Wind (Frederiks et al., GCN 36809), thus confirming that it is likely GRB 240703A, using the Thai Response Telescope (TRT) SBO node and the JinShan 100C & 50A telescopes. Image subtraction of the stacked 5 x 360 s R-band TRT image against the PanSTARRS archival r-band image reveals multiple optical afterglow candidates, among which an uncatalogued optical transient (OT) is localized at coordinates R.A. (J2000) = 18:15:03.89 Dec. (J2000) = -09:42:02.96 with an uncertainty of ~ 0.5 arcsec. The OT has r ~ 20.4 +/- 0.1 mag at a median time of ~ 13.9 hr post-trigger, calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction of A_r ~ 3 mag. We then obtained 10 x 300 s frames in the Sloan r-band and 10 x 300 s in the Sloan z-band at the JinShan 100C telescope. The OT is not detected in the stacked r-band image down to r ~ 22.2 mag at a median time of 16.07 hr post-trigger, also not detected in z-band down to z ~ 20.6 mag at a median time of 16.91 hr post-trigger, both calibrated with the nearby PanSTARRS field. The presence and the decay of the OT make it an optical afterglow candidate of EP240703a/GRB 240703A. View this GCN Circular online at https://gcn.nasa.gov/circulars/36815. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34667] IPN triangulation of GRB 240627A
by GCN Circulars 03 Jul '24

03 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36814 SUBJECT: IPN triangulation of GRB 240627A DATE: 24/07/03 17:35:46 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team, E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, G. Waratkar, V. Jethwani, J.Joshi, V. Bhalerao, D. Bhattacharya, and S. Vadawale, on behalf of the Astrosat-CZTI team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The bright, long-duration GRB 240627A (AstroSat-CZTI detection: Joshi et al., GCN 36776; NuSTAR anti-coincidence shields detection: Grefenstette, GCN 36778; CALET-CGBM detection: Kobayashi et al., GCN 36798) was detected by Astrosat (CZTI), Konus-Wind, INTEGRAL (SPI-ACS), NuSTAR (ACS), CALET (CGBM), and Mars-Odyssey (HEND) at about 86341 s UT (23:59:01). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 164.155 (10h 56m 37s) +72.806 (+72d 48' 23") Corners: 166.270 (11h 05m 05s) +73.674 (+73d 40' 25") 166.346 (11h 05m 23s) +73.611 (+73d 36' 38") 162.228 (10h 48m 55s) +71.917 (+71d 55' 02") 162.147 (10h 48m 35s) +71.979 (+71d 58' 45") --------------------------------------------- The error box area is 416 sq. arcmin, and its maximum dimension is 2.1 deg (the minimum one is 3.4 arcmin). The Sun distance was 60 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB240627_T86332/IPN The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/36814. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34666] GRB 240619A: Host galaxy redshift from VLT/X-shooter
by GCN Circulars 03 Jul '24

03 Jul '24

TITLE: GCN CIRCULAR NUMBER: 36813 SUBJECT: GRB 240619A: Host galaxy redshift from VLT/X-shooter DATE: 24/07/03 15:58:09 GMT FROM: Laura Cotter <laura.cotter(a)ucdconnect.ie> L. Cotter (UCD), B. Schneider (MIT), D. Xu (NAOC), J. T. Palmerio (GEPI, Obs. de Paris), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. de Ugarte Postigo (CNRS, OCA, LAM), G. Pugliese (Amsterdam), B. P. Gompertz (Birmingham), A. Martin-Carrillo (UCD), A. Rossi (INAF), D. Hartmann (Clemson Univ.), T. Aishwarya (INAF), N. R. Tanvir (Leicester), A. J. Levan (Radboud) report on behalf of the Stargate collaboration: We observed the location (Gompertz et al., GCN 36715; Capalbi et al., GCN 36721; Mo et al., GCN 36739; Rhodes et al., GCN 36744) of the Fermi GRB 240619A (Fermi GBM team, GCN 36694; Preis et al., GCN 36695; Dalessi et al., GCN 36717) using the X-shooter spectrograph mounted on the ESO VLT UT3 (Melipal). The observation was performed on 2024 July 02 (13.8 days after the GRB). It consisted of 4 exposures of 600 s each and covered the wavelength range 3000-21000 AA. The target is faintly detected in the r-band acquisition image, with an AB magnitude r ~ 22.8 (calibration is difficult due to paucity of calibrators in the field). This is significantly brighter than the archival object visible in the Pan-STARRS and Legacy surveys, first noticed by Gompertz et al. (GCN 36715), and likely includes a transient contribution. In a preliminary reduction, we detect several strong emission lines that we identify as H-alpha, H-beta, H-gamma, the [O II] doublet, [O III] 4959, [O III] 5007, and [Ne III] 3869 at a common redshift of z = 0.3965, which is lower than the photometric value reported in the PS1-STRM catalog (Beck et al. 2020) for galaxy PSO J162.3946+17.2828. We therefore propose this to be the redshift of the GRB. The Legacy survey images also show a second, fainter object about 1.7" west of the optical afterglow position. This was also included in the slit, and we measure for it z = 1.338 from detection of [O II] and H-alpha. Given the larger offset, we consider this galaxy to be unrelated to the GRB. We acknowledge expert support from the ESO staff in Paranal, in particular Matias Jones and Thomas Szeifert. View this GCN Circular online at https://gcn.nasa.gov/circulars/36813. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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