Obscured Activity: AGN, Quasars, Starbursts and ULIGs Observed by the Infrared Space Observatory

Verma, Aprajita; Charmandaris, V.; Klaas, U.; Lutz, D.; Haas, Martín

doi:10.1007/1-4020-3844-5_15

Cited by 3 publications

(4 citation statements)

References 211 publications

(323 reference statements)

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“…Because they are difficult to observe from the ground, the observations of the pure rotational lines of H 2 from external galaxies started with the Infrared Space Observatory (ISO), and continued with the Spitzer infrared (IR) satellite (e.g. Valentijn and van der Werf, 1999;Lutz et al, 2003;Verma et al, 2005). In star forming galaxies, rotational H 2 line emission is thought to come from PDRs (Rigopoulou et al, 2002;Higdon et al, 2006;Roussel et al, 2007).…”

Section: H 2 Transitions and Specific Diagnostic Powermentioning

confidence: 99%

H 2 formation on interstellar dust grains: The viewpoints of theory, experiments, models and observations

Wakelam

Bron

Cazaux

et al. 2017

Molecular Astrophysics

231

201

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a b s t r a c tMolecular hydrogen is the most abundant molecule in the universe. It is the first one to form and survive photo-dissociation in tenuous environments. Its formation involves catalytic reactions on the surface of interstellar grains. The micro-physics of the formation process has been investigated intensively in the last 20 years, in parallel of new astrophysical observational and modeling progresses. In the perspectives of the probable revolution brought by the future satellite JWST, this article has been written to present what we think we know about the H 2 formation in a variety of interstellar environments.

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Section: H 2 Transitions and Specific Diagnostic Powermentioning

confidence: 99%

H 2 formation on interstellar dust grains: The viewpoints of theory, experiments, models and observations

Wakelam

Bron

Cazaux

et al. 2017

Molecular Astrophysics

231

201

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“…This ‘warm/cold’ terminology is based on the implication that dust heated by an AGN would reach higher temperatures and hence lower the continuum slope between 25 and 60 μm (or 24 and 70 μm in Spitzer 's case) (e.g. Farrah et al 2005; Verma et al 2005; Frayer et al 2006). Calculating the 25/60 μm continuum slope using the model SEDs reveals that for ∼25 per cent of our sample the classical IRAS warm source criterion of f 25 / f 60 > 0.17 applies.…”

Section: Sed Characterizationmentioning

confidence: 99%

“…Conventional methods of characterizing infrared galaxies include associating flux ratios between various bands to physical processes responsible for emission in the infrared (e.g. Xu et al 2001; Egami et al 2004; Lutz et al 2005; Verma et al 2005). In particular, the f 25 / f 60 parameter has been applied extensively in IRAS studies of such systems to quantify relative AGN/starburst contributions with an indicative value of f 25 / f 60 > 0.17 for AGN‐dominated sources (e.g.…”

Section: Sed Characterizationmentioning

confidence: 99%

The properties of 70 μm-selected high-redshift galaxies in the Extended Groth Strip

Symeonidis¹,

Willner²,

Rigopoulou³

et al. 2008

Monthly Notices RAS

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We examine the infrared properties of 43 high‐redshift (0.1 < z < 1.2), infrared‐luminous galaxies in the Extended Groth Strip (EGS), selected by a deep 70 μm survey with the Multiband Imaging Photometer on Spitzer (MIPS). In addition and with reference to starburst‐type spectral energy distributions (SEDs), we derive a set of equations for estimating the total infrared luminosity (LIR) in the range 8–1000 μm using photometry from at least one MIPS band. 42 out of 43 of our sources' optical/infrared SEDs (λobserved < 160 μm) are starburst type, with only one object displaying a prominent power‐law near‐infrared continuum. For a quantitative analysis, models of radiation transfer in dusty media are fit on to the infrared photometry, revealing that the majority of galaxies are represented by high extinction, Av > 35, and for a large fraction (∼50 per cent) the SED turns over into the Rayleigh–Jeans regime at wavelengths longward of 90 μm. For comparison, we also fit semi‐empirical templates based on local galaxy data; however, these underestimate the far‐infrared SED shape by a factor of at least 2 and in extreme cases up to 10 for the majority (∼70 per cent) of the sources. Further investigation of SED characteristics reveals that the mid‐infrared (70/24 μm) continuum slope is decoupled from various galaxy properties such as the total infrared luminosity and far‐infrared peak, quantified by the L160/L70 ratio. In view of these results, we propose that these high‐redshift galaxies have different properties to their local counterparts, in the sense that large amounts of dust cause heavy obscuration and are responsible for an additional cold emissive component, appearing as a far‐infrared excess in their SEDs.

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“…A large fraction of the extragalactic sources detected in the far infrared were spiral galaxies, quasars (QSOs), Seyfert galaxies, and early type galaxies (Genzel & Cesarsky, 2000), but also new classes of galaxies very bright in the IR, such as ULIRGs (ultra-luminous infrared galaxies), were found. IR satellite missions, focusing on selected areas, were followed by MSX (Midcourse Space Experiment, e.g., Egan et al, 2003), ISO (Infrared Space Observatory,e.g., Verma et al, 2005;Genzel & Cesarsky, 2000), and SST (The Spitzer Space Telescope, e.g., Soifer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Dusty Universe viewed by AKARI far infrared detector

et al. 2013

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We present the results of the analysis of multiwavelength Spectral Energy Distributions (SEDs) of far-infrared galaxies detected in the AKARI Deep Field-South (ADF-S) Survey. The analysis uses a carefully selected sample of 186 sources detected at the 90 μm AKARI band, identified as galaxies with cross-identification in public catalogues. For sources without known spectroscopic redshifts, we estimate photometric redshifts after a test of two independent methods: one based on using mainly the optical-mid infrared range, and one based on the whole range of ultraviolet-far infrared data. We observe a vast improvement in the estimation of photometric redshifts when far infrared data are included, compared with an approach based mainly on the optical-mid infrared range. We discuss the physical properties of our far-infrared-selected sample. We conclude that this sample consists mostly of rich in dust and young stars nearby galaxies, and, furthermore, that almost 25% of these sources are (Ultra)Luminous Infrared Galaxies. Average SEDs normalized at 90 μm for normal galaxies (138 sources), LIRGs (30 sources), and ULIRGs (18 galaxies) show a significant shift in the peak wavelength of the dust emission, and an increasing ratio between their bolometric and dust luminosities which varies from 0.39 to 0.73.

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Obscured Activity: AGN, Quasars, Starbursts and ULIGs Observed by the Infrared Space Observatory

Cited by 3 publications

References 211 publications

H 2 formation on interstellar dust grains: The viewpoints of theory, experiments, models and observations

H 2 formation on interstellar dust grains: The viewpoints of theory, experiments, models and observations

The properties of 70 μm-selected high-redshift galaxies in the Extended Groth Strip

Dusty Universe viewed by AKARI far infrared detector

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