A low-dispersion Keck I spectrum of SN 1980K taken in August 1995 (t = 14.8 yr after explosion) and a November 1997 MDM spectrum (t = 17.0 yr) show broad 5500 km s^{-1} emission lines of H\alpha, O I ...6300,6364 A, and O II 7319,7330 A. Weaker but similarly broad lines detected include Fe II 7155 A, S II 4068,4072 A, and a blend of Fe II lines at 5050--5400 A. The presence of strong S II 4068,4072 A emission but a lack of S II 6716,6731 A emission suggests electron densities of 10^{5-6} cm^{-3}. From the 1997 spectra, we estimate an H\alpha flux of 1.3 \pm 0.2 \times 10^{-15} erg cm^{-2} s^{-1} indicating a 25% decline from 1987--1992 levels during the period 1994 to 1997, possibly related to a reported decrease in its nonthermal radio emission.
Astron.J.132:2268-2288,2006 We are performing a uniform and unbiased, ~7x7 degrees imaging survey of the
Large Magellanic Cloud (LMC), using the IRAC and MIPS instruments on board the
Spitzer Space ...Telescope in order to survey the agents of a galaxy's evolution
(SAGE), the interstellar medium (ISM) and stars in the LMC. The detection of
diffuse ISM with column densities >1.2x10^21 H cm^-2 permits detailed studies
of dust processes in the ISM. SAGE's point source sensitivity enables a
complete census of newly formed stars with masses >3 solar masses that will
determine the current star formation rate in the LMC. SAGE's detection of
evolved stars with mass loss rates >1x10^-8 solar masses per year will quantify
the rate at which evolved stars inject mass into the ISM of the LMC. The
observing strategy includes two epochs in 2005, separated by three months, that
both mitigate instrumental artifacts and constrain source variability. The SAGE
data are non-proprietary. The data processing includes IRAC and MIPS pipelines
and a database for mining the point source catalogs, which will be released to
the community in support of Spitzer proposal cycles 4 and 5. We present initial
results on the epoch 1 data with a special focus on the N79 and N83 region. The
SAGE epoch 1 point source catalog has ~4 million sources. The point source
counts are highest for the IRAC 3.6 microns band and decrease dramatically
towards longer wavelengths consistent with the fact that stars dominate the
point source catalogs and that the dusty objects, e.g. young stellar objects
and dusty evolved stars that detected at the longer wavelengths, are rare in
comparison. We outline a strategy for identifying foreground MW stars, that may
comprise as much as 18% of the source list, and background galaxies, that may
comprise ~12% of the source list.
We are performing a uniform and unbiased, ~7x7 degrees imaging survey of the Large Magellanic Cloud (LMC), using the IRAC and MIPS instruments on board the Spitzer Space Telescope in order to survey ...the agents of a galaxy's evolution (SAGE), the interstellar medium (ISM) and stars in the LMC. The detection of diffuse ISM with column densities >1.2x10^21 H cm^-2 permits detailed studies of dust processes in the ISM. SAGE's point source sensitivity enables a complete census of newly formed stars with masses >3 solar masses that will determine the current star formation rate in the LMC. SAGE's detection of evolved stars with mass loss rates >1x10^-8 solar masses per year will quantify the rate at which evolved stars inject mass into the ISM of the LMC. The observing strategy includes two epochs in 2005, separated by three months, that both mitigate instrumental artifacts and constrain source variability. The SAGE data are non-proprietary. The data processing includes IRAC and MIPS pipelines and a database for mining the point source catalogs, which will be released to the community in support of Spitzer proposal cycles 4 and 5. We present initial results on the epoch 1 data with a special focus on the N79 and N83 region. The SAGE epoch 1 point source catalog has ~4 million sources. The point source counts are highest for the IRAC 3.6 microns band and decrease dramatically towards longer wavelengths consistent with the fact that stars dominate the point source catalogs and that the dusty objects, e.g. young stellar objects and dusty evolved stars that detected at the longer wavelengths, are rare in comparison. We outline a strategy for identifying foreground MW stars, that may comprise as much as 18% of the source list, and background galaxies, that may comprise ~12% of the source list.
