[vsolj-alert 94] W Com very bright (Tosti)

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

W Com very bright (Tosti)

  BL Lac型天体のW Comが歴史的な明るさに達しつつあります。眼視観測者でも
　Poynerが短時間変動を報告していましたが、それが裏付けられています。
　昨年のBL Lac同様の密度の高い観測が望まれます。

  Forwarded message from Dr. Toshi:

From TOSTI@astrpg.pg.infn.it Wed Apr 22 19:36 JST 1998
Date: Wed, 22 Apr 1998 12:35:10 +0200
To: tkato@kusastro.kyoto-u.ac.jp
Message-ID: <vsolj-alert94@hoge.baba.hajime.jp>
From: <Gino.Tosti@PG.infn.it>
Subject: W Com
Content-Type: text
Content-Length: 1419

Dear Friends,

WCom (ON 231) is becoming one of the brightest Blazar in the sky 

These are our last observation.

WCom 1924.39124 1998.04.20 21.23.23  1.03 360.0 V  13.16 00.04
WCom 1924.55225 1998.04.21 01.15.15  1.46 300.0 V  13.30 00.04

WCom 1925.37585 1998.04.21 21.01.09  1.03 360.0 V  12.74 00.04
WCom 1925.45325 1998.04.21 22.52.37  1.08 360.0 V  12.54 00.03
WCom 1925.49316 1998.04.21 23.50.08  1.18 360.0 V  12.69 00.04
WCom 1925.55310 1998.04.22 01.16.29  1.48 300.0 V  12.58 00.04


We carried  out an intensive  monitoring
campaign in the period from March 1994 to March 1997
(Tosti et al., 1998, A&AS, in press)

During this period WCom was characterized by the
presence of three major outbursts having the observed
maxima in March 1995,  February 1996, and January 1997.
The maximum observed value was V=13.61 during the 1996 burst.

The observation on April 21-22 show that the source has a 
V magnitude that is about 1 mag brighter than in 1996.

Considering that after the deep minimum observed in 1972-74 the  
mean magnitude of the source started to increase and that this  
increasing luminosity trend
is still going on, the photographic value of 11.6 observed in 1911 
by Wolf (1916) should be reconsidered.  

The exceptional activity state of W Com could offer a good opportunity to
study in detail the emission mechanism so intensive multifrequency
monitoring are strongly recommended.


Gino

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