https://www.astronomerstelegram.org Binary, from The Astronomer's Telegram en-us 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=17820 S. Le Stum, F. Cangemi, A. Coleiro, S. Guillot, L. Zhang S. Le Stum, F. Cangemi, A. Coleiro, S. Guillot, L. Zhang lestum@apc.in2p3.fr Credentialed by: Floriane Cangemi (cangemi@apc.in2p3.fr) The Astronomer's Telegram ATel17820 We report a spectral softening of the microquasar Cygnus X-3 detected on 2026 May 27 by the ECLAIRs coded-mask instrument onboard the SVOM mission. The long-term ECLAIRs light curve had shown a progressive hardening of the source from 2026 March 30 until 2026 May 12. ... 2026-05-29T07:12:51-00:00 https://www.astronomerstelegram.org/?read=17818 Alessio Marino, Francesco Coti Zelati, Nanda Rea, Yilong Wang, Giulia Illiano, Minghao Zhang, Chen Wang, Biao Zhang, Jiapei Feng, Haiwu Pan Alessio Marino, Francesco Coti Zelati, Nanda Rea, Yilong Wang, Giulia Illiano, Minghao Zhang, Chen Wang, Biao Zhang, Jiapei Feng, Haiwu Pan marino@ice.csic.es Credentialed by: Alessio Marino (marino@ice.csic.es) The Astronomer's Telegram ATel17818 We report on the detection of a new outburst from the neutron star low-mass X-ray binary MXB 1730-335 (a.k.a. the Rapid Burster) with the Wide-field X-ray Telescope (WXT) onboard Einstein Probe (EP). ... 2026-05-27T15:18:27-00:00 https://www.astronomerstelegram.org/?read=17816 M. Nakajima, T. Mihara, H. Negoro, K. Saito, T. Yokoyama, M. Wada, T. Tamagawa, N. Kawai, M. Matsuoka, T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida, Y. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara, M. Shidatsu, C. Kang, T. Nakamoto, M. Uenishi, T. Usuki, S. Yatsuzuka, I. Takahashi, Y. Yatsu, S. Nakahira, S. Ueno, H. Tomida, M. Kurihara, Y. Ueda, K. Fujiwara, S. Kobayashi, M. Yamauchi, M. Nishio, C. Hiraizumi, K. Yamaoka, M. Sugizaki, W. Iwakiri, T. Kawamuro, S. Yamada, S. Ogawa M. Nakajima, T. Mihara, H. Negoro, K. Saito, T. Yokoyama, M. Wada, T. Tamagawa, N. Kawai, M. Matsuoka, T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida, Y. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara, M. Shidatsu, C. Kang, T. Nakamoto, M. Uenishi, T. Usuki, S. Yatsuzuka, I. Takahashi, Y. Yatsu, S. Nakahira, S. Ueno, H. Tomida, M. Kurihara, Y. Ueda, K. Fujiwara, S. Kobayashi, M. Yamauchi, M. Nishio, C. Hiraizumi, K. Yamaoka, M. Sugizaki, W. Iwakiri, T. Kawamuro, S. Yamada, S. Ogawa nakajima.motoki@nihon-u.ac.jp Credentialed by: Motoki Nakajima (nakajima.motoki@nihon-u.ac.jp) The Astronomer's Telegram ATel17816 The MAXI/GSC nova alert system triggered on a weak X-ray brightening from the Be/X-ray binary pulsar LS V +44 17 (RX J0440.9+4431) on 2026 May 22 (MJD 61182). ... 2026-05-27T02:00:01-00:00 https://www.astronomerstelegram.org/?read=17815 M. Nakajima, T. Mihara, M. Sugizaki, H. Negoro, K. Saito, T. Yokoyama, M. Wada, T. Tamagawa, N. Kawai, M. Matsuoka, T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida, Y. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara, M. Shidatsu, C. Kang, T. Nakamoto, M. Uenishi, T. Usuki, S. Yatsuzuka, I. Takahashi, Y. Yatsu, S. Nakahira, S. Ueno, H. Tomida, M. Kurihara, Y. Ueda, K. Fujiwara, S. Kobayashi, M. Yamauchi, M. Nishio, C. Hiraizumi, K. Yamaoka, W. Iwakiri, T. Kawamuro, S. Yamada, S. Ogawa M. Nakajima, T. Mihara, M. Sugizaki, H. Negoro, K. Saito, T. Yokoyama, M. Wada, T. Tamagawa, N. Kawai, M. Matsuoka, T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida, Y. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara, M. Shidatsu, C. Kang, T. Nakamoto, M. Uenishi, T. Usuki, S. Yatsuzuka, I. Takahashi, Y. Yatsu, S. Nakahira, S. Ueno, H. Tomida, M. Kurihara, Y. Ueda, K. Fujiwara, S. Kobayashi, M. Yamauchi, M. Nishio, C. Hiraizumi, K. Yamaoka, W. Iwakiri, T. Kawamuro, S. Yamada, S. Ogawa nakajima.motoki@nihon-u.ac.jp Credentialed by: Motoki Nakajima (nakajima.motoki@nihon-u.ac.jp) The Astronomer's Telegram ATel17815 The MAXI/GSC nova alert system triggered on an X-ray brightening from the Be/X-ray binary pulsar 1A 0535-66 (also known as 1A 0538-66) on 2026 May 21 (MJD 61181; see the MAXI alert page at https://maxi.riken.jp/alert/novae/1181387701/1181387701.htm ). ... 2026-05-26T14:00:05-00:00 https://www.astronomerstelegram.org/?read=17814 K. Tsubono, K. Asuma, K. Niinuma, K. Takefuji and T. Daishido K. Tsubono, K. Asuma, K. Niinuma, K. Takefuji and T. Daishido tsubono@phys.s.u-tokyo.ac.jp Credentialed by: Kimio Tsubono (tsubono@phys.s.u-tokyo.ac.jp) The Astronomer's Telegram ATel17814 We report the apparent fading of the recent radio rebrightening activity from Cygnus X-3 observed with the Nasu radio telescope array at 1.4 GHz, following our previous reports (ATel #17746, #17758). ... 2026-05-26T04:44:32-00:00 https://www.astronomerstelegram.org/?read=17809 T. Takagi, M. Shidatsu, T. Mihara, M. Nakajima, M. Sugizaki T. Takagi, M. Shidatsu, T. Mihara, M. Nakajima, M. Sugizaki takagi.toshihiro.bb@ehime-u.ac.jp Credentialed by: Megumi Shidatsu (shidatsu.megumi.wr@ehime-u.ac.jp) The Astronomer's Telegram ATel17809 The X-ray binary pulsar GX 1+4 has been in a long-term spin-down phase, characterized by a gradual decrease in pulse frequency, from the 1980s until recently. ... 2026-05-22T17:48:41-00:00 https://www.astronomerstelegram.org/?read=17784 Marchev, D. ; Borisov, B. ; Atanasova-Sartliiska, T. ; Yordanova, G. ; Georgiev, A. ; Marchev, V. Marchev, D. ; Borisov, B. ; Atanasova-Sartliiska, T. ; Yordanova, G. ; Georgiev, A. ; Marchev, V. vlad.marchev@gmail.com Credentialed by: Vladislav Marchev (vlad.marchev@gmail.com) The Astronomer's Telegram ATel17784 We present our recent photometric observations of T CrB obtained on the 5th and 6th of May 2026 and we compare them with the ones from ATel#17052 an year ago. ... 2026-05-09T14:36:32-00:00 https://www.astronomerstelegram.org/?read=17770 F. Cangemi, A. Coleiro, M. Dennefeld, O. Godet, D. Götz, S. Guillot, S. Le Stum, H.-L. Li, S. Schanne, L. Tao, L.-P. Xin, L. Zhang F. Cangemi, A. Coleiro, M. Dennefeld, O. Godet, D. Götz, S. Guillot, S. Le Stum, H.-L. Li, S. Schanne, L. Tao, L.-P. Xin, L. Zhang cangemi@apc.in2p3.fr Credentialed by: Floriane Cangemi (cangemi@apc.in2p3.fr) The Astronomer's Telegram ATel17770 On Monday, April 27, 2026, at 13:58:46.114 UT, the onboard trigger software of the SVOM/ECLAIRs telescope detected and localized a source at R.A. = 284.818 deg and Dec. ... 2026-04-30T09:35:08-00:00 https://www.astronomerstelegram.org/?read=17760 M. Brunet, F. Cangemi, S. Guillot, A. Coleiro, L. Zhang M. Brunet, F. Cangemi, S. Guillot, A. Coleiro, L. Zhang marius.brunet@irap.omp.eu Credentialed by: Floriane Cangemi (cangemi@apc.in2p3.fr) The Astronomer's Telegram ATel17760 On Tuesday, April 19th 2026, at 01:02:07.9 UTC (T0), the SVOM/ECLAIRs (4-150 keV) coded-mask telescope detected a Type I burst via an offline search with the event-by-event data downloaded through the X-band ground station. ... 2026-04-21T13:16:55-00:00