https://www.astronomerstelegram.org For reporting and commenting upon new observations of astronomical transients by the professional astrophysics community. en-us https://www.astronomerstelegram.org/?read=17840 Lara Sidoli Lara Sidoli sidoli@lambrate.inaf.it Credentialed by: Lara Sidoli (sidoli@lambrate.inaf.it) The Astronomer's Telegram ATel17840 A new X-ray transient has been recently discovered by the Einstein Probe (EP), EP260531a (ATel#17828). Its sky position has been refined with the Follow-up X-ray Telescope (FXT; ATel#17833). ... 2026-06-10T08:57:32-00:00 https://www.astronomerstelegram.org/?read=17839 Thomas Maccarone on behalf of the South Pole Telescope consortium Thomas Maccarone on behalf of the South Pole Telescope consortium thomas.maccarone@ttu.edu Credentialed by: Tom Maccarone (thomas.maccarone@ttu.edu) The Astronomer's Telegram ATel17839 The South Pole Telescope collaboration report millimeter flaring from SPT-SV J211659.7-592000. The source at this position has been marginally detected in SPT data since 2021, with a mean flux density of 1.6+-0.5mJy at 90 GHz and 1.9+-0.4 mJy at 150 GHz, and with ASKAP at about 9 mJy.. ... 2026-06-08T19:02:33-00:00 https://www.astronomerstelegram.org/?read=17838 E. Jehin, J. Manfroid, S. Hmiddouch, K. Aravind E. Jehin, J. Manfroid, S. Hmiddouch, K. Aravind ejehin@uliege.ac.be Credentialed by: Emmanuel Jehin (ejehin@uliege.be) The Astronomer's Telegram ATel17838 The author reports that they obtained, using the TRAPPIST-North (Z53) telescope located in Morocco, observations of comet 220P on the nights of June 4 and 5, a few days after a large outburst of -6 mag was reported (ATEL#17829). ... 2026-06-08T18:55:30-00:00 https://www.astronomerstelegram.org/?read=17837 L. Qian, Y. C. Zhang, M. Zhu, P. Jiang, G. Y. Zhang, L. Y. Wang, X. Y. Zhang, R. P. Eatough, Z. Pan L. Qian, Y. C. Zhang, M. Zhu, P. Jiang, G. Y. Zhang, L. Y. Wang, X. Y. Zhang, R. P. Eatough, Z. Pan lqian@nao.cas.cn Credentialed by: Lei Qian (lqian@nao.cas.cn) The Astronomer's Telegram ATel17837 We performed a systematic search of single pulses by a TransientX-based pipeline with a dispersion measure range of 10 cm^-3 pc to 5000 cm^-3 pc in the POP (Piggyback Observation of Pulsars, https://fast.bao.ac.cn/cms/article/2034282224688386050) survey, with a S/N threshold of 8.0. ... 2026-06-07T15:46:51-00:00 https://www.astronomerstelegram.org/?read=17836 S. A. Trushkin, P. G. Tsybulev, N. N. Bursov, S. A. Trushkin, P. G. Tsybulev, N. N. Bursov, sergei.trushkin@gmail.com Credentialed by: Sergei Trushkin (satr@sao.ru) The Astronomer's Telegram ATel17836 We carry out the multi-frequency monitoring of the Galactic microquasars with the RATAN-600 radio telescope on 10 January, 6 and 26 April, and now on 6 June 2026 we detected the giant flares from the X-ray and Gamma-ray binary, microquasar Cygnus X-3 at frequencies 1.45 - 30 GHz (see ATel #17742). ... 2026-06-07T09:42:51-00:00 https://www.astronomerstelegram.org/?read=17835 Yuhua Yao, Justin Vandenbroucke for the IceCube Collaboration Yuhua Yao, Justin Vandenbroucke for the IceCube Collaboration justin.vandenbroucke@wisc.edu Credentialed by: Justin Vandenbroucke (justin.vandenbroucke@wisc.edu) The Astronomer's Telegram ATel17835 The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search for track-like muon neutrino events arriving from the direction of the flat-spectrum radio quasar (FSRQ) OQ 334 (B2 1420+326). ... 2026-06-06T21:42:20-00:00 https://www.astronomerstelegram.org/?read=17834 G. L. Huang, Z. X. Li, J. Y. Cao, J. W. Hu, Y. Liu on behalf of the Einstein Probe team G. L. Huang, Z. X. Li, J. Y. Cao, J. W. Hu, Y. Liu on behalf of the Einstein Probe team ep_ta@bao.ac.cn Credentialed by: Yuan Liu (liuyuan@bao.ac.cn) The Astronomer's Telegram ATel17834 In ATel #17828, the Galactic coordinates of the X-ray transient EP260531a were given incorrectly due to a coordinate conversion error. The correct Galactic coordinates are l = 357.773 deg and b = -0.689 deg. ... 2026-06-06T03:08:33-00:00 https://www.astronomerstelegram.org/?read=17833 G. L. Huang, Z. X. Li, J. Y. Cao, J. W. Hu, Y. Liu on behalf of the Einstein Probe team G. L. Huang, Z. X. Li, J. Y. Cao, J. W. Hu, Y. Liu on behalf of the Einstein Probe team ep_ta@bao.ac.cn Credentialed by: Yuan Liu (liuyuan@bao.ac.cn) The Astronomer's Telegram ATel17833 The Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission performed a follow-up observation of the X-ray transient EP260531a (ATel #17828) on 2026-06-04 07:33:43 (UTC), with a net exposure of 6 ks. ... 2026-06-05T08:37:41-00:00 https://www.astronomerstelegram.org/?read=17832 Federico Manzini, David Augustin, Raoul Behrend, Costantino Sigismondi, Virginio Oldani, Alessandra C. Mura, Paolo Ochner, Andrea Farina, Luigi R. Bedin, Andrea Reguitti, Mohamed Aboushelib Federico Manzini, David Augustin, Raoul Behrend, Costantino Sigismondi, Virginio Oldani, Alessandra C. Mura, Paolo Ochner, Andrea Farina, Luigi R. Bedin, Andrea Reguitti, Mohamed Aboushelib manzini.ff@aruba.it Credentialed by: Andrea Reguitti (andreareguitti@gmail.com) The Astronomer's Telegram ATel17832 In ATel #17831, we forgot to report the Telegram Title: Determination of the rotation period of Comet 10P (Tempel). We apologize for the inconvenience. ... 2026-06-04T19:29:11-00:00 https://www.astronomerstelegram.org/?read=17831 Federico Manzini, David Augustin, Raoul Behrend, Costantino Sigismondi, Virginio Oldani, Alessandra C. Mura, Paolo Ochner, Andrea Farina, Luigi R. Bedin, Andrea Reguitti, Mohamed Aboushelib Federico Manzini, David Augustin, Raoul Behrend, Costantino Sigismondi, Virginio Oldani, Alessandra C. Mura, Paolo Ochner, Andrea Farina, Luigi R. Bedin, Andrea Reguitti, Mohamed Aboushelib manzini.ff@aruba.it Credentialed by: Andrea Reguitti (andreareguitti@gmail.com) The Astronomer's Telegram ATel17831 Comet 10P (the second comet discovered by W. Tempel in Milan in 1873), a short period comet, is approaching perihelion on August 2, 2026, at a heliocentric distance of approximately 1.42 AU (JPL/Horizons, https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=10p). ... 2026-06-04T18:10:35-00:00