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[vsolj-alert 992] SN 2002bj suddenly faded?



山岡@九大理 です。

さきほど英文でも流しましたが、SN 2002bjが急減光か? との情報を伺いまし
た。明るいIIn型と思われている天体ですが、この種の天体ではこれまでこの
ような急減光が観測されたことはありません。

確認と、今後の動向が非常に急がれます。17等台と考えて観測されることが勧
められます。

			九州大学(六本松地区)理学部物理学教室  山岡  均
			〒810-8560 福岡市中央区六本松4-2-1
			yamaoka@rc.kyushu-u.ac.jp

c.f. 2002bjの発見時の情報です。

>Date: Sat, 2 Mar 2002 10:36:46 +0900 (JST)
From: Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>
Subject: [vsnet-alert 7209] SN 2002bj in NGC 1821

Dear SN watchers,

  A bright (discovery mag 14.7-8) SN was discovered by Puckett Obs.
and the LOTOSS KAIT.  It seems a young object and somewhat luminous as
in NGC 1821. 

  SN 2002bj was discovered on Feb. 28, and confirmed on the next
night at the nearly same magnitude.  It was not detected on Feb. 21,
so it seems a young object.  The position of SN (by KAIT team) is:
R.A. = 5h11m46s.37, Decl. = -15o08'10".7 (2000.0), which is about 5"
east and 6" south of the apparent center of a irregular-shaped
(IB(s)m) galaxy NGC 1821.  It lies superimposed on the central bar.  

  The recession velocity of NGC 1821 is 3608 km/s (NED value) and
there is notable Galactic extinction (A_V \sim 0.3 mag).  If this
velocity is of the Hubble flow, the expected maximum for typical SN Ia
is mag about 15.3, which is already overcome by the discovery mag.  
The spectroscopic confirmation and further magnitude monitoring is
urged.

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

>Date: Thu, 7 Mar 2002 14:08:57 +0900 (JST)
From: Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>
Subject: [vsnet-campaign-sn 363] spectral types of recent SNe

Dear SN watchers,

  IAUC 7844 informed the spectral types of several recent SNe.

(snip)

SN 2002bj: 

In [vsnet-campaign-sn 361] or [vsnet-alert 7209]:
>  The recession velocity of NGC 1821 is 3608 km/s (NED value) and
>there is notable Galactic extinction (A_V \sim 0.3 mag).  If this
>velocity is of the Hubble flow, the expected maximum for typical SN Ia
>is mag about 15.3, which is already overcome by the discovery mag.  
>The spectroscopic confirmation and further magnitude monitoring is
>urged.

  This SN is also of type II, but shows somewhat peculiar feature.  It
does not show a prominent H-alpha emission but a very blue continuum
with shallow features, and it resembles that of SN II 2001hg or
luminous SN IIn 1998S (Gunma team and CfA group).  It is mag about
14.7 on Mar. 3, which suggest that it is quite luminous.

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

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