Apparently independent discovery reports of a supernova in NGC 3504 have been received (both from observations made at Mauna Kea) from Eric Emsellem, Observatoire de Lyon, via CCD images obtained on Mar. 31.272 UT at the Canada-France-Hawaii Telescope (CFHT), and from Geoffrey Clayton and Karl Gordon, Louisiana State University, via separate J, H, and K images taken on Mar. 2.38 with the NASA Infrared Telescope Facility. Emsellem notes that the star is located at R.A. = 11h03m11s.21, Decl. = +27o58'21".0 (equinox 2000.0), which is 0".6 east and 5".3 south of the center of NGC 3504. Clayton provides position end figures 12s.01, 13".2. Emsellem calculates that the object had a flux of 6.7 x 10E-16 erg sE-1 cmE-2 AE-1 at 900 nm on Mar. 31, and he roughly estimates I about 15. Clayton reports J = 14.5, K = 12.8 for Mar. 2. The star was not present in January, when a K observation of NGC 3504 was obtained with the CFHT Adaptive Optics Bonnette, and it is not present in other archival images, including JHK images taken in May 1996 at the Kitt Peak 2.1-m telescope (Elmegreen et al. 1997, A.J. 114, 1850) and in Dec. 1997 at Mt. Laguna Observatory. Note that this galaxy contains an apparent double nucleus, as well. P. Garnavich, Harvard-Smithsonian Center for Astrophysics, reports that inspection of a spectrum (range 840-900 nm) taken with the CFHT integral spectrograph OASIS on Mar. 31.312 (and provided by Emsellem) reveals what appears to be a broad Ca II P-Cyg profile characteristic of a supernova.
International Astronomical Union Circular
- Pub Date:
- May 1998