The 18 centimeter OH emission of IC 4553 (Arp 220)

Abstract

view Abstract Citations (40) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The 18 Centimeter OH Emission of IC 4553 (Arp 220) Baan, Willem A. ; Haschick, Aubrey D. Abstract All transitions of hedroxyl have been found in emission in IC 4553 (Arp 220). The line shapes have been decomposed and interpreted in terms of three distinct emission regions: one region at the systemic velocity of the galaxy, and a second at a 334 km/s higher velocity. A third region represents a nuclear outflow with a terminal velocity of approximately 700 km/s. The emission lines for the region I are the strongest and originate in a molecular disk surrounding the nucleus of the galaxy. The infalling foreground region II is thought to be rather extended and has a very prominennt 1612 MHz line. The line ratios of regions I and II are quite different indicating that, although the primary pump for both regions is the infrared radiation field, there are differences in the (secondary) excitation conditions. Regions I and II may represent the two nuclei of the galaxies, which make up the merging IC 4553. The excitation of region III is collisional. Publication: The Astrophysical Journal Pub Date: July 1987 DOI: 10.1086/165356 Bibcode: 1987ApJ...318..139B Keywords: Centimeter Waves; Emission Spectra; Galactic Nuclei; Galactic Rotation; Gas Dynamics; Hydroxyl Emission; Astronomical Spectroscopy; Interstellar Matter; Molecular Clouds; Radial Velocity; Radio Spectra; Astrophysics; GALAXIES: INDIVIDUAL ALPHANUMERIC: IC 4553; GALAXIES: INTERNAL MOTIONS; GALAXIES: NUCLEI; INTERSTELLAR: MOLECULES full text sources ADS | data products SIMBAD (1) NED (1)