$Herschel$/PACS OH Spectroscopy of Seyfert, LINER, and Starburst Galaxies

Abstract

We investigated the 65$\mu$m, 71$\mu$m, 79$\mu$m, 84$\mu$m, 119$\mu$m, and 163$\mu$m OH doublets of 178 local (0 < $z$ < 0.35) galaxies. They were observed using the $Herschel$/PACS spectrometer, including Seyfert galaxies, LINERs, and star-forming galaxies. We observe these doublets exclusively in absorption (OH71), primarily in absorption (OH65, OH84), mostly in emission (OH79), only in emission (OH163) and an approximately even mix of the both (OH119). In 19 galaxies we find P-Cygni or reverse P-Cygni line profiles in the OH doublets. We use several galaxy observables to probe spectral classification, brightness of a central AGN/starburst component, and radiation field strength. We find that OH79, OH119, and OH163 are more likely to display strong emission for bright, unobscured AGN. For less luminous, obscured AGN and non-active galaxies, we find populations of strong absorption (OH119), weaker emission (OH163), and a mix of weak emission and weak absorption (OH79). For OH65, OH71 and OH84, we do not find significant correlations with the observables listed above. We do find relationships between OH79 and OH119 with both the 9.7$\mu$m silicate feature and Balmer decrement dust extinction tracers in which more dust leads to weaker emission / stronger absorption. The origin of emission for the observed OH doublets, whether from collisional excitation, or from radiative pumping by infrared photons, is discussed.

29 pages, 10 figures, 5 machine readable tables and 6 supplemental figures available upon request

References in corpus (15)

• Array Programming with NumPy
• The NumPy array: a structure for efficient numerical computation
• Massive molecular outflows and negative feedback in ULIRGs observed by Herschel-PACS
• Mid-IR Galaxy Classification Based on Silicate Obscuration and PAH Equivalent Width
• Molecular outflows in local ULIRGs: energetics from multi-transition OH analysis
• Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
• Far-infrared line spectra of active galaxies from the Herschel/PACS Spectrometer: the complete database
• Spitzer-IRS high resolution spectroscopy of the 12μm Seyfert galaxies: I. First results
• Resolving the AGN and host emission in the mid-infrared using a model-independent spectral decomposition
• On the LINER nuclear obscuration, Compton-thickness and the existence of the dusty torus; Clues from Spitzer/IRS spectra
• A complete census of silicate features in the mid-infrared spectra of active galaxies
• High-excitation OH and H_2O lines in Markarian 231: the molecular signatures of compact far-infrared continuum sources
• Far-infrared line spectra of Seyfert galaxies from the Herschel-PACS Spectrometer
• Galaxy evolution studies with the SPace IR telescope for Cosmology and Astrophysics (SPICA): the power of IR spectroscopy
• Emission Line Properties of Seyfert Galaxies in the 12 Micron Sample

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