[vsnet-j 608] MKN421 outburst

[Taichi Kato <tkato>]

MKN421 outburst

　BL Lac型天体の MKN421 がアウトバーストしています。観測には都合の良い季節
　です。

Subject: [vsnet-alert 5597] (fwd) Mkn 421 outburst

Date: Mon, 22 Jan 2001 18:00:34 -0500 (EST)
From: Ron Remillard <rr@space.mit.edu>
Subject: [vsnet-alert 0] Mkn 421 outburst

H.G. Boerst (University of Kiel), N. Goetting (University of Hamburg),
and R. Remillard,(MIT) report on behalf of the HEGRA Collaboration 
and the ASM/RXTE Team: 

Following the detection of enhanced X-ray emission from the BL Lac 
object Markarian 421 with the RXTE All Sky Monitor on, observations 
with the Cherenkov telescopes of HEGRA (La Palma, Canary Islands, Spain) 
show very strong TeV activity. Above a threshold energy of 500 GeV, 
daily integrated fluxes (20 minute averages) reach up to 
1, 4, 2, 1.5, 2.5, and 3 times the TeV flux of the Crab Nebula 
in consecutive nights during January 16-22. The ASM observations 
of Mkn 421 in mCrab at 2-12 keV: 44(2) over UT 2001 January 13-18; 
30(3) Jan 19-20; 54(3) on Jan 21, and 80(6) on Jan 22. 
Today's peak is the brightest X-ray flux seen from a BL Lac object 
during the RXTE Mission (since Jan 1996). Observations at other wavelengths 
are strongly encouraged.  

For updates on the TeV activity and the HEGRA schedule, see
"http://vsnet-hegra.desy.de/mrk-421/";.

_____

　位置は以下の通りです。

110427.1 +381231 (2000.0) QSO_MARK421 HP 12. z=0.031

　可視光では 1/17 の Wnt さんの観測が最後で、ここしばらくモニターがやや
　手薄になっていた時期のようです。