[vsnet-alert 23551] a new outburst of MAXI J1807+132

[mkimura]

a new outburst of MAXI J1807+132

As Denis noticed that, this object entered a new outburst.
According to the following ATel, the nature of this system is unknown
(the central object is a neutron star, or a black hole, or not ?),
so optical follow-up observations are encouraged.

Regards,
Mariko


-------- Forwarded Message --------
Subject: 	ATel #13097
From: 	atel at astronomerstelegram.org
To: 	mkimura at kusastro.kyoto-u.ac.jp



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The Astronomer's Telegram http://www.astronomerstelegram.org

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ATEL #13097 ATEL #13097

Title: MAXI/GSC detects a new outburst of MAXI J1807+132
Author: . Shidatsu (Ehime U.),H. Negoro, M. Nakajima, W. Maruyama,
M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka
(RIKEN), T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida
(AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo
U.), N. Kawai, M. Sugizaki, M. Oeda, K. Shiraishi (Tokyo Tech), S. 
Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, N. Isobe,
R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada,
S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama,
K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara,
K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka
(Nagoya U.), Y. Kawakubo (LSU) Queries: shidatsu.megumi.wr at ehime-u.ac.jp
Posted: 11 Sep 2019; 08:39 UT
Subjects:X-ray, Binary, Transient, Variables

On September 10, the MAXI/GSC nova-alert system detected the X-ray transient
MAXI J1807+132, discovered in 2017 (Negoro et al. 2017, ATel #10208), after
a ~2-year quiescence. The 4-10 keV flux, averaged for September 8-10, was
estimated to be 19 +/- 6 mCrab. An optical brightening, detected with Gaia
on September 6, was also reported via Variable Star Network (Denisenko
et al. 2019, VSNET-alert 23544). We note that the source was in the FoV
of a low-sensitivity GSC camera until September 7 and has become observable
with normal cameras since September 8. To monitor the outburst and 
investigate the nature of the compact object,
which is still unclear (Shidatsu et al. 2017, Jim'enez-Ibarra et al. 2018),
follow-up observations are highly encouraged.
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Password Certification: Megumi Shidatsu (shidatsu at kusastro.kyoto-u.ac.jp)
http://www.astronomerstelegram.org/?read=13097
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