------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2581 2009 Sep 03 15.14UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- UGC 2773 OT2009-1 (=OPTICAL TRANSIT IN UGC 2773) On TA E-Circular 2579 we reported on an optical transit in UGC 2773 found by Tom Boles but which has so far not been confirmed as a supernova. In a further report on The Astronomer's Telegram 2187, E. Berger and R. Foley at Harvard report optical spectroscopy and a possible progenitor for this object. They observed the transient source (hereafter UGC2773 OT2009-1) with the Gemini Multi-Object Spectrograph on the Gemini-North 8-m telescope on 2009 September 2.60UT. A pair of 1200 sec exposures were obtained with a wavelength coverage of 5000-9000A at a resolution of about 3.5A. The spectrum is dominated by a bright and narrow H-alpha emission line with a width of about 350 km/s, strong CaII IR triplet lines with an apparent P Cygni profile (with the minimum blue-shifted by 365 km/s relative to the systemic velocity of UGC 2773),[CaII] emission lines, and NaI D lines with a P Cygni profile. At the distance of UGC 2773 (m-M = 28.82 mag) the discovery absolute magnitude of UGC2773 OT2009-1 is M ~ -12.7 mag (taking into account a Galactic extinction of A_R = 1.5 mag). Additional extinction within the host galaxy is possible. From the GMOS acquisition image they find that the object is located at the following coordinates (J2000): RA = 03:32:07.22 DEC = +47:47:39.7 (2000) They obtained archival Hubble Space Telescope images taken with the Wide Field Planetary Camera 2 instrument. Differential astrometry of the GMOS image relative to the WFPC2/F606W image reveals a coincident source in both WFPC2 filters. The HST images at the location of UGC2773 OT2009-1 are available from: http://www.cfa.harvard.edu/~eberger/ugc2773_ot2009-1_hst.gif The spectral properties of UGC2773 OT2009-1 are reminiscent of the recent intermediate-luminosity transient in NGC300 (Berger et al. 2009, ApJ, 699, 1850). However, the progenitor of NGC300 OT2008-1 was completely dust-obscured and visible only in Spitzer images. Furthermore, no P Cygni absorption was seen in any of the lines. Another possibility is that UGC2773 OT2009-1 is a sub-luminous type IIP supernova similar to SN1997D which had a peak M_V>-14.65 mag (Turatto et al. 1998, ApJ, 498, L129). However, even at +1 year, the spectra of SN1997D exhibited H-alpha FWHM of about twice the width we measure for UGC2773 OT2009-1 (Benetti et al. 2001, MNRAS, 322, 361), while early spectra exhibit an H-alpha P Cygni profile, not see here. A final possibility is an LBV outburst, but the strong CaII emission would be unexpected in this case. SUPERNOVA 2009hl IN ANONYMOUS GALAXY Discovery by CRTS of a possible supernova (CBET 1879): SN 2009 UT R.A. (2000.0) Decl. Mag. Offset 2009hl Jly 11.40 17 31 10.14 +36 25 40.1 18.0 92.7"W,52.4"S J. M. Silverman et. al., University of California, Berkeley, report that CCD spectra of July 16UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows it is a normal type-Ia supernova near maximum light. Guy M Hurst