Sunday, July 28, 2013


Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Supernova in M74 (TOCP Designation: PSN J01364816+1545310) we 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 our images taken on July 27.7, 2013 we can confirm the presence of an optical counterpart with R-filtered CCD magnitude 13.0 and V-filtered CCD magnitude 12.6 at coordinates:

R.A. = 01 36 48.20, Decl.= +15 45 31.0

(equinox 2000.0; UCAC-3 catalogue reference stars).

Our annotated confirmation image (single 120-second exposures under a cloudy sky):

An animation showing a comparison between our confirmation image and the archive POSS2/UKSTU plate (R Filter - 1990). Click here or on the thumbnail for a bigger version:

Animation of Possible Supernova in M74 by E. Guido & N. Howes photo possible_supernova_M74_July_27_2013_Guido_Howes_zps330c6433.gif

UPDATE - July 28, 2013

According to CBET 3606 this transient has been discovered by LOSS supernova survey on unfiltered KAIT images obtained on July 25.45.

D. D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada; M. L. Graham, Las Cumbres Observatory Global Telescope, University of California at Santa Barbara; and E. Y. Hsiao, Las Campanas Observatory, report that a spectrogram (range 369-700 nm, resolution 0.3 nm) of PSN J01364816+1545310 = SN 2013ej, obtained on 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.

This young type II supernova has been officially designated 2013ej.

This is the third supernova in M74 over the last eleven years (previous SN were: SN 2002ap and SN 2003gd).

Other info about this bright supernova are available through Atel (The Astronomer's Telegram):

ATel 5228: Spectroscopic classification for PSN J01364816+1545310 in M74 with FLOYDS at Faulkes Telescope South  

ATel 5229: The Probable Progenitor of PSN J01364816+1545310 in M74

ATel 5230: Possible Spitzer Counterpart of PSN J01364816+1545310

Below you can see our image of supernova 2013ej IN M74 obtained on 2013 July 28.7. Click on it for a bigger version. (R-magnitude 12.8; B-magnitude 12.0)

by Ernesto Guido & Nick Howes

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