Star formation in NGC 4449: MAMA-detector UV imagery and Fabry-Perot Balmer-line imagery

Abstract

view Abstract Citations (31) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Star Formation in NGC 4449: MAMA-Detector UV Imagery and Fabry-Perot Balmer-Line Imagery Hill, Robert S. ; Home, Allen T. ; Smith, Andrew M. ; Bruhweiler, Fred C. ; Cheng, K. P. ; Hintzen, Paul M. N. ; Oliversen, Ronald J. Abstract Using far-ultraviolet (FUV) and Balmer-line imagery, we investigate the star formation history of 22 large OB complexes in the Magellanic irregular galaxy NGC 4449. The FUV luminosity of NGC 4449 is comparable to those of late-type spirals and is greater than that of the LMC by 2.4 mag, indicating substantial star formation in the last 10^8^ yr. FUV data were taken using a sounding-rocket telescope with a Multianode Microchannel Array (MAMA) detector, and Balmer-line data were taken using the Goddard Fabry-Perot Imager. The resulting imagery shows bright, roughly coincident FUV and Hα sources throughout the extent of the visible galaxy. We model these sources using cluster-evolution codes. Although all sources are a few Myr old, clear age differences are found. In particular, several of the most recently active star formation regions are located together in the galaxy's northern periphery, which is apparently coincident with a large H I reservoir. The brightest and most massive OB complexes are found along the northeast-southwest surface brightness ridgeline (the "bar"). Over the entire galaxy, star formation rates are consistent on timescales of 10^6^, 10^8^, and 10^9^ yr. A history of recent star formation is suggested with two main episodes, one predominantly in the bar ending ~5 Myr ago, and an ongoing one associated with an observed H I cloud. Publication: The Astrophysical Journal Pub Date: August 1994 DOI: 10.1086/174431 Bibcode: 1994ApJ...430..568H Keywords: Balmer Series; Galactic Clusters; Galactic Evolution; Irregular Galaxies; Luminosity; Star Formation; Ultraviolet Spectroscopy; Astronomical Models; Cosmology; Fabry-Perot Interferometers; Multi-Anode Microchannel Arrays; Spectrum Analysis; Ultraviolet Astronomy; Ultraviolet Photometry; Astrophysics; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4449; GALAXIES: STELLAR CONTENT; STARS: EVOLUTION; STARS: FORMATION; TECHNIQUES: INTERFEROMETRIC; ULTRAVIOLET: STARS full text sources ADS | data products SIMBAD (29) NED (7)