------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2935 2013 Jly 28 14.46UT 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 ------------------------------------------------------------------- SUPERNOVA 2013ej IN M74 (LOSS) 2013ej Jly 25.45 01 36 48.16 +15 45 31.0 13.5 92.5"E 135 "S The object was observed again on July 26.44 UT at mag 13.1, having increased about 0.4 mag in one day, indicating that it may be a young supernova on the rise. M. W. Richmond, Rochester Institute of Technology, confirms the presence of a bright new transient in Messier 74 at the above position; CCD images taken with the RIT Observatory's 30-cm Schmidt-Cassegrain telescope (+ SBIG ST-8E camera with Bessell filters) around July 27.21 indicate that the variable is very blue. Dave D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada et. al., report that a spectrogram of July 27.41 UT with the 1.82-m Plaskett Telescope of the National Research Council of Canada, shows a moderately blue continuum with weak Balmer emission lines showing P-Cyg profiles, suggesting that this is a core-collapse event. S. D. Van Dyk (IPAC/Caltech) et. al. report on The Astronomer's Telegram 5229 the identification of the probable progenitor in archival Hubble Space Telescope (HST) Advanced J01364816+Camera for Surveys/Wide Field Channel (WFC) images in bands F435W, F555W, and F814W from 2003 November and 2005 June. The exact position of the PSN was located in the HST images via adaptive-optics NIRC2-NGS K'-band imaging at the Keck-II 10-m telescope on 2013 July 27 UT. A precise astrometric registration was performed between the HST F814W drizzled mosaic and a coaddition of the 15 1-sec NIRC2 wide-camera exposures. Even without applying a distortion correction to the NIRC2 frames before coaddition, using 10 stars in close proximity to the PSN in common between the two image sets we were able to achieve an uncertainty of 1.05 WFC pixels (52 milliarcsec) in the X-direction and 0.75 pixels (38 milliarcsec) in the Y-direction. We therefore found the PSN in the NIRC2 images to correspond directly in the HST images to a star which is particularly bright in F814W. We find that the star has B=25.03, V=24.65 (+/-0.02), and I=22.61 mag. Correcting for an assumed distance of 8.6 Mpc and for only the Galactic foreground extinction, we find that the star has M(V)_0=-5.2 and (V-I)_0=1.96 mag. These are consistent with the properties of an M-type red supergiant (RSG), which is not unexpected for the classification of the PSN as a young Type II SN (ATel 5228). We note, however, that (B-V)_0=0.32 mag, which is too blue for a RSG and may indicate that the profile of this star is contaminated by another, bluer object. Messier 74 was also host to the Type Ic SN 2002ap and the Type II-P SN 2003gd. The probable progenitor of the PSN is apparently more luminous than the RSG progenitor of SN 2003gd. Ernesto Guido notifies TAHQ that he and Nick Howes performed some follow-up of this object remotely through a 0.43-m f/6.8 astrograph + CCD of ITelescope network (MPC Code Q62 - Siding Spring, AU). On their images taken on 2013 July 27.7UT they confirm the presence of an optical counterpart with R-filtered CCD magnitude 13.0 and V-filtered CCD magnitude 12.6 at coordinates: RA = 01 36 48.20, DEC +15 45 31.0 (2000) (using UCAC-3) Our annotated confirmation image: http://bit.ly/177HYw5 Guy M Hurst