Mid-Infrared line diagnostics of active galaxies - A spectroscopic AGN survey with ISO-SWS

By E. Sturm, D. Lutz, A. Verma, H. Netzer, A. Sternberg, A. Moorwood, E. Oliva, R. Genzel. 2002

180 citations recorded by the source corpus.

We present medium resolution (R 1500) ISO-SWS 2.4-45m spectra of a sample of 29 galaxies with active nuclei. This data set is rich in fine structure emission lines tracing the narrow line regions and (circum-)nuclear star formation regions, and it provides a coherent spectroscopic reference for future extragalactic studies in the mid-infrared. We use the data set to briefly discuss the physical conditions in the narrow line regions (density, temperature, excitation, line profiles) and to test for possible dierences between AGN sub-types. Our main focus is on new tools for determining the properties of dusty galaxies and on the AGN-starburst connection. We present mid-IR line ratio diagrams which can be used to identify composite (starburst+ AGN) sources and to distinguish between emission excited by active nuclei and emission from (circum-nuclear) star forming regions. For instance, line ratios of high to low excitation lines like (O IV)25.9m/(Ne II)12.8m, that have been used to probe for AGNs in dusty objects, can be examined in more detail and with better statistics now. In addition, we present two- dimensional diagnostic diagrams that are fully analogous to classical optical diagnostic diagrams, but better suited for objects with high extinction. Finally, we discuss correlations of mid-infrared line fluxes to the mid- and far-infrared continuum. We compare these relations to similar relations in starburst galaxies in order to examine the contribution of AGNs to the bolometric luminosities of their host galaxies. The spectra are available in electronic form from the authors.

Subfields: Astronomy and Astrophysics, Instrumentation, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/e0fe276ea2a871bf92c28a668a42e2afa455cc89

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Citations in the corpus

Towards a complete census of AGN in nearby Galaxies: a large population of optically unidentified AGN (2009, background): “Local mid-IR surveys (e.g., Sturm et al. 2002; the Spitzer Infrared Nearby Galaxy Survey [SINGS] Legacy Project [Dale et al. 2006; hereafter D06] and S08) have shown the advantages of using mid-IR spectroscopy as an AGN diagnostic.”
Mid-Infrared Spectra of Classical AGNs Observed with the Spitzer Space Telescope (2005, methodology): “The presence of AGN is best verified by the detection of high ionization lines such as [NeV] and/or [OIV] (Sturm et al. 2002).”
Star Formation in NGC 5194 (M51a): The Panchromatic View from GALEX to Spitzer (2005, background): “One of the 133 regions coincides with the Seyfert 2 nucleus (Ford et al. 1985; Goad & Gallagher 1985; Terashima & Wilson 2001; Sturm et al. 2002), which is excluded from our analysis.”
A NEW DIAGNOSTIC OF ACTIVE GALACTIC NUCLEI: REVEALING HIGHLY ABSORBED SYSTEMS AT REDSHIFT >0.3 (2011, background): “9µm or [Nev]λ14µm in the infrared regime (Sturm et al. 2002; Armus et al. 2004, 2007; Diamond-Stanic et al. 2009; Rigby et al. 2009; LaMassa et al. 2010).”
ISM properties in low-metallicity environments I. mid-infrared spectra of dwarf galaxies (2005, background): “…demonstrated the widely-varying MIR characteristics of low metallicity starburst galaxies (Madden 2000), which differ remarkably from those of the more metal-rich starburst galaxies (e.g. Rigopoulou et al. 1999; Laurent et al. 2000; Sturm et al. 2000, 2002; Förster Schreiber et al. 2003).”