The Astronomical Journal
An apparent late-time optical recovery of SN 1985L (Type II-L) in the Sb galaxy NGC 5033 is presented and discussed. An Hα emission point source is found within 1'' of both SN 1985L's historically reported position 70'' west and 55'' north of NGC 5033's center and its late-time, radio-measured position. This Hα source is not visible on V-band or narrow red continuum (7000 ± 125 Å) images, but is detected using a 6510 Å filter (FWHM = 30 Å). Its detection at 6510 Å can be attributed to blueshifted Hα emission because of a broad (±5000 km s-1) Hα line profile like that seen in late-time Type II-L spectra. The SN 1985L source has an estimated total Hα flux of (5 ± 1) × 10-16 ergs cm-2 s-1, making it, at a distance of 13 Mpc, about as luminous as the late-time Hα emission from SN 1970G. The presence of Hα emission from SN 1985L suggests that it has a spectrum similar to that of other comparably aged Type II-L supernovae, and further helps establish a late-time radio-optical link for this subclass of Type II events.
Fesen, Robert A., "A Late-Time Optical Detection of SN 1985L in NGC 5033" (1998). Open Dartmouth: Faculty Open Access Articles. 2120.