Near-infrared observations of ionized hydrogen at the core of the Galaxy

Abstract

view Abstract Citations (15) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-infrared observations of ionized hydrogen at the core of the Galaxy. Bally, J. ; Joyce, R. R. ; Scoville, N. Z. Abstract We report observations of the Ba and By lines in the recombination spectrum of hydrogen from the galactic center. The observed Ba/By intensity ratio compared with that expected from recombination theory yields an estimate of the reddening and the visual extinction to the galactic center of Av = 32 mag. This extinction can be supplied entirely by dust associated with the known gas component (mostly H2) in the galactic disk outside the center region. We therefore conclude that the giant molecular cloud at +40 km 1 seen in the direction of Sgr A is probably on the far side of the nucleus. The observed recombination lines imply quite conclusively that most of the fine structure on scale of 1 "-30" appearing in radio-frequency continuum maps of the galactic center has a thermal rather than a nonthermal origin. The photon production rate required to maintain constant ionization within the inner 1 pc H II region is Q0 = 1050 photons 1 Subject headings: galaxies: Milky Way - galaxies: nuclei - infrared: sources Publication: The Astrophysical Journal Pub Date: May 1979 DOI: 10.1086/157026 Bibcode: 1979ApJ...229..917B Keywords: Galactic Nuclei; Hydrogen; Interstellar Extinction; Ionized Gases; Milky Way Galaxy; Near Infrared Radiation; Gas Ionization; Line Shape; Optical Thickness; Astrophysics; Galactic Center:Hydrogen; Galactic Center:Infrared Radiation full text sources ADS |