[IAUC] CBET 648: 20060926 : 2006gy IN NGC 1260

[IAUC mailing list]

                                                  Electronic Telegram No. 648
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html


2006gy IN NGC 1260
     J. L. Prieto, Ohio State University; and P. Garnavich, A. Chronister,
and P. Connick, University of Notre Dame, report that they obtained spectra
of 2006gy (cf. CBET 644, 647) with the Kitt Peak 4-m telescope (+ RC
spectrograph) on Sept. 26.4 UT.  The spectra show a strong red continuum
with broad Balmer emission and broad He I emission at 600 nm.  Deep, narrow
interstellar absorption lines of Na I and Ca II from the host galaxy are
clearly seen.  The equivalent width of the Na I absorption in the host
galaxy is 0.51 nm, suggesting that the continuum color derives from heavy
dust extinction.  The spectrum is suggestive of a dust-extinguished
type-IIn event.  However, the Balmer lines are symmetric, which is unusual
for supernovae in their early phases.  The source showed no offset from the
galaxy core in the 4-m TV guider.  The brightening event could be an
active-galactic-nucleus (AGN) outburst from a strongly extincted galaxy
core.  Comparing the Na I absorption from the Milky Way and host with the
Milky Way reddening, the line-of-sight visual extinction is estimated to be
about 2 magnitudes.  Given the estimated apparent magnitude of the event
(CBET 644), the absolute magnitude of a supernova would be -22, which is
more consistent with an AGN.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2006 CBAT
2006 September 26                (CBET 648)               Daniel W. E. Green