Near-infrared spectra and classification diagnostics of Seyfert galaxies

Abstract

view Abstract Citations (92) References (60) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-Infrared Spectra and Classification Diagnostics of Seyfert Galaxies Osterbrock, Donald E. ; Tran, Hien D. ; Veilleux, Sylvain Abstract In this second paper of the series, observational results of our spectroscopic survey of Seyfert galaxies in the near-infrared are presented, and the potential for using emission-line ratios in this spectral region as a classification diagnostic tool is examined. Near-infrared CCD spectra, which cover the range λλ7000-10000 at nominal resolution FWHM ~12 A, of 15 additional Seyferts and two starburst galaxies were obtained with the Lick Observatory 3 m Shane telescope. Relative emission-line intensities from these observations, in combination with measurements from our first paper (Osterbrock, Shaw, & Veilleux) and those of Morris & Ward as well as additional Lick observations and measurements of new, high signal-to- noise ratio optical spectra of many of these objects, are used to study the diagnostic diagrams involving [S III] λλ9069, 9531/Hα, [O II] λλ7320, 7330/Hα, [S II] λλ6716, 6731/Hα, and [O III] λ5007/Hβ. Comparisons are made in these diagrams between observational data from the active galaxies and published measurements of H II region-like objects as well as with predictions from simple one-component models calculated for the two types of objects. Our results suggest that diagnostic diagrams using near-IR lines such as [O Il] λλ7320, 7330 and [S III] λλ9069, 9531 promise to provide a powerful method in classifying emission-line galaxies. Most but not all the diagnostic diagrams can be understood on the basis of photoionization models. There may be some heating due to relativistic electrons in addition to photoionization in active galactic nuclei (AGNs), but this is not at all clear. Publication: The Astrophysical Journal Pub Date: April 1992 DOI: 10.1086/171197 Bibcode: 1992ApJ...389..196O Keywords: Active Galactic Nuclei; Emission Spectra; Infrared Sources (Astronomy); Infrared Spectra; Seyfert Galaxies; Sky Surveys (Astronomy); Charge Coupled Devices; H Ii Regions; Infrared Astronomy; Near Infrared Radiation; Photoionization; Signal To Noise Ratios; Starburst Galaxies; Astrophysics; GALAXIES: NUCLEI; GALAXIES: SEYFERT; INFRARED: GALAXIES full text sources ADS | data products SIMBAD (74) NED (21)