[vsnet-alert 18915] Re: V4641 Sgr active (ATEL)

[Alexandre Amorim]

Hi friends

I observed visually V4641 Sgr region today (2015-07-30, ~22:30 TU) and nothing brighter than mag 12.0 was detected. Full Moon and a thin nebulosity interfered.

-
  Conheça os eventos celestes do ano
"Anuário Astronômico Catarinense 2015"
      http://www.costeira1.rg10.net

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Em qui, 30/7/15, Taichi Kato <tkato at kusastro.kyoto-u.ac.jp> escreveu:

 Assunto: [vsnet-alert 18913] V4641 Sgr active (ATEL)
 Para: variable_star_forum at yahoogroups.com, vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp, vsnet-alert at yahoogroups.com, vsnet-campaign-xray at ooruri.kusastro.kyoto-u.ac.jp
 Data: Quinta-feira, 30 de Julho de 2015, 21:47
 
 V4641 Sgr active (ATEL)
 
    As everyone? knows, this object showed
 violent optical
 variation during the active phase in 2002 and others.
 
 ===
 
 ATEL #7858       
            
          
    ATEL #7858
 
 Title:    MAXI/GSC detection of renewed
 activity of the black hole candidate
         V4641 Sgr
 Author:    T. Yoshii (Tokyo Tech), H. Negoro,
 (Nihon U.), S. Ueno, H.
         Tomida, S. Nakahira,
 M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
         T. Mihara, M.
 Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi,
         M. Matsuoka (RIKEN),
 N. Kawai, Y. Tachibana (Tokyo Tech), A. Yoshida,
         T. Sakamoto, Y.
 Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani
         (Osaka U.), M.
 Nakajima, T. Masumitsu, K. Tanaka (Nihon U.), Y. Ueda,
         T. Kawamuro, T. Hori
 (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.),
         M. Yamauchi, D. Itoh
 (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii
         (ISM) report on behalf
 of the MAXI team:
 Queries:    negoro at phys.cst.nihon-u.ac.jp
 Posted:    30 Jul 2015; 15:04 UT
 Subjects:X-ray, Binary, Black Hole, Transient
 
 We report on an enhancement of X-ray flux from the black
 hole candidate
 V4641 Sgr detected with MAXI/GSC. The MAXI/GSC nova alert
 system triggered
 the event at 19:16 on 2015 July 29 (UT) (MJD 57232) (for the
 trigger event,
 see http://maxi.riken.jp/pipermail/x-ray-star/2015-July/000387.html).
 MAXI
 daily light curves of this source show that this new
 outburst has started
 around 2015 July 20, and the 2-4 keV and 4-10 keV fluxes
 have gradually
 increased, reaching 17.3 +/- 8.8 and 26.9 +/- 8.2 mCrab on
 MJD57232.0-57233.0,
 respectively.
 
 The long-term 2-10 keV light curve of MAXI/GSC shows at
 least three outbursts
 with peak fluxes of beyond about 5 mCrab around MJD 55420
 (ATel #2785,
 #2832, #2892) ,MJD 56090 and MJD 56660 (ATel #5803, #5836),
 and the interval
 is about 600 days.
 
 The latest light curves and image of this source are
 available at the following
 URL: http://maxi.riken.jp/top/index.php?cid=1&jname=J1819-254.
 Multi-wavelength
 observations are encouraged.