Far-infrared line spectra of active galaxies from the Herschel/PACS spectrometer: The complete database

Journal Article · Sat Oct 01 04:00:00 EDT 2016 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.3847/0067-0049/226/2/19· OSTI ID:22872472

Fernández-Ontiveros, Juan Antonio; Spinoglio, Luigi ^[1]; Pereira-Santaella, Miguel ^[2]; Malkan, Matthew A. ^[3]; Andreani, Paola ^[4]

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1. Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)
2. Centro de Astrobiología (CSIC/INTA), Ctra. de Torrejón a Ajalvir, km 4, E-28850 Torrejón de Ardoz, Madrid (Spain)
3. Astronomy Division, University of California, Los Angeles, CA 90095-1547 (United States)
4. European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748, Garching (Germany)

We present a coherent database of spectroscopic observations of far-IR fine-structure lines from the Herschel/Photoconductor Array Camera and Spectrometer archive for a sample of 170 local active galactic nuclei (AGNs), plus a comparison sample of 20 starburst galaxies and 43 dwarf galaxies. Published Spitzer/IRS and Herschel/SPIRE line fluxes are included to extend our database to the full 10–600 μm spectral range. The observations are compared to a set of Cloudy photoionization models to estimate the above physical quantities through different diagnostic diagrams. We confirm the presence of a stratification of gas density in the emission regions of the galaxies, which increases with the ionization potential of the emission lines. The new [O iv]{sub 25.9μm}/[O iii]{sub 88μm} versus [Ne iii]{sub 15.6μm}/[Ne ii]{sub 12.8μm} diagram is proposed as the best diagnostic to separate (1) AGN activity from any kind of star formation and (2) low-metallicity dwarf galaxies from starburst galaxies. Current stellar atmosphere models fail to reproduce the observed [O iv]{sub 25.9μm}/[O iii]{sub 88μm} ratios, which are much higher when compared to the predicted values. Finally, the ([Ne iii]{sub 15.6μm} + [Ne ii]{sub 12.8μm})/([S iv]{sub 10.5μm} +[S iii]{sub 18.7μm}) ratio is proposed as a promising metallicity tracer to be used in obscured objects, where optical lines fail to accurately measure the metallicity. The diagnostic power of mid- to far-infrared spectroscopy shown here for local galaxies will be of crucial importance to study galaxy evolution during the dust-obscured phase at the peak of the star formation and black hole accretion activity (1

• OSTI ID: 22872472
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 2 Vol. 226; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTROSCOPY
BLACK HOLES
CAMERAS
COSMIC DUST
DIAGRAMS
FAR INFRARED RADIATION
GALAXY NUCLEI
INFRARED SPECTRA
IONIZATION POTENTIAL
METALLICITY
MILKY WAY
PHOTOCONDUCTORS
PHOTODETECTORS
PHOTOIONIZATION
STELLAR ATMOSPHERES
TELESCOPES