//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30149 SUBJECT: MAXI GRB210607.82: Global MASTER-Net observations report DATE: 21/06/07 23:17:07 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (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. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (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 MAXI GRB210607.82 (trigger No 372671890,17h 33m 42.24s , -22d 37m 22.8s, R=1) errorbox 46 sec after notice time and 12291 sec after trigger time at 2021-06-07 23:07:59 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 68 deg. The sun altitude is -20.3 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the MAXI GRB210607.82 errorbox 97 sec after notice time and 12342 sec after trigger time at 2021-06-07 23:08:50 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 68 deg. The sun altitude is -18.7 deg. The galactic latitude b = 5 deg., longitude l = 4 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1630751 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 12381 | 2021-06-07 23:07:59 | MASTER-Tavrida | (17h 30m 36.86s , -22d 29m 42.1s) | C | 180 | 17.4 | 12433 | 2021-06-07 23:08:50 | MASTER-Kislovodsk | (17h 34m 32.26s , -22d 10m 55.8s) | P| | 180 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30150 SUBJECT: GRB 210607A/MAXI J1733-222: MAXI/GSC detection DATE: 21/06/08 00:12:49 GMT FROM: Hitoshi Negoro at Nihon U K. Kobayashi, H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, K. Asakura, K. Seino (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, K. Komachi, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered on an X-ray transient source at 19:43:06 UT on 2021 June 7. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (263.367 deg, -22.279 deg) = (17 33 28, -22 16 44) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.56 deg and 0.53 deg, respectively. The roll angle of the long axis from the north direction is 69.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 59 +- 21 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at 18:10 UT and in the next transit at 21:16 UT with an upper limit of 20 mCrab for each. Since the source showed a soft X-ray spectrum and no significant time variations during the scan and the source is located in the galactic bulge region at (l, b) ~ (4.2 deg, 5.8 deg), it is possible that the source is a galactic transient source. We tentatively name the source MAXI J1733-222.