VLA radio recombination line observations of Sagittarius A West

Abstract

view Abstract Citations (31) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS VLA Radio Recombination Line Observations of Sagittarius A West Roberts, D. A. ; Goss, W. M. ; van Gorkom, J. H. ; Leahy, J. P. Abstract With a resolution of 2.4 arcsec and an rms noise of 0.4 mJy/beam, the northern arm and bar of Sagittarius A (Sgr A) West have been observed in the H92-alpha radio recombination line (RRL) at 8.3 GHz, using the Very Large Array (VLA). Zeeman observations of several positions in the northern arm have yielded upper limits of 15 mG (3 sigma) for the line-of-sight magnetic field. In the bar region within 30 arcsec of Sgr A asterisk, the increase in electron temperature suggested by van Gorkom et al. (1985), has been confirmed. Values of the electron temperature in the range 20,000-40,000 K are observed. The H92-alpha spectra have similar shapes to those of (Ne II) at 12.8 microns; thus, pressure broadening is not important in influencing the line widths of these high-frequency recombination lines. Publication: The Astrophysical Journal Pub Date: January 1991 DOI: 10.1086/185899 Bibcode: 1991ApJ...366L..15R Keywords: Galactic Nuclei; Radio Sources (Astronomy); Very Large Array (Vla); Astronomical Spectroscopy; Electron Energy; Interstellar Magnetic Fields; Radio Spectra; Sagittarius Constellation; Zeeman Effect; Astrophysics; GALAXIES: NUCLEI; GALAXIES: THE GALAXY; INTERFEROMETRY; RADIO SOURCES: LINES full text sources ADS | data products SIMBAD (1)