We present an analysis of, [O I]_(63) [O III]_(88), [N II]_(122), and [C II]_(158) far-infrared (FIR) fine-structure line observations obtained with Herschel/PACS, for ~240 local luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. We find pronounced declines ("deficits") of line-to-FIR continuum emission for [N II]_(122) , [O I]_(63) and [C II]_(158) as a function of FIR color and infrared luminosity surface density, Σ_(IR). The median electron density of the ionized gas in LIRGs, based on the [N II]_(122)/[N II]_(205) ratio, is n_e = 41 cm^(−3). We find that the dispersion in the [C II]_(158) deficit of LIRGs is attributed to a varying fractional contribution of photodissociation regions (PDRs) to the observed [C II]_(158) emission, f([C II]^(PDR)_(158)) = [C II]^(PDR)_(158)/[C II]_(158), which increases from ~60% to ~95% in the warmest LIRGs. The [O I]_(63)/[C II]^(PDR)_(158) ratio is tightly correlated with the PDR gas kinetic temperature in sources where [O 1]_(63) is not optically thick or self-absorbed. For each galaxy, we derive the average PDR hydrogen density, n_H, and intensity of the interstellar radiation field, G, in units of G_0 and find G/n_H ratios of ~0.1–50 G_0 cm^3, with ULIRGs populating the upper end of the distribution. There is a relation between G/n_H and Σ_(IR), showing a critical break at Σ*_(IR) 5 × 10^(10) L⊙ kpc^(−2). Below Σ*_(IR), G/n_H remains constant, 0.32 G_0 cm^3, and variations in Σ_(IR) are driven by the number density of star-forming regions within a galaxy, with no change in their PDR properties. Above Σ*_(IR), G/n_H increases rapidly with Σ_(IR), signaling a departure from the typical PDR conditions found in normal star-forming galaxies toward more intense/harder radiation fields and compact geometries typical of starbursting sources.

/pdf/a-herschel-pacs-far-infrared-line-emission-survey-of-local-3tme6kuwah.pdf

A Herschel/PACS Far-infrared line emission survey of local luminous infrared galaxies

https://hal.archives-ouvertes.fr/hal-01800298/document

H2 formation on interstellar dust grains: The viewpoints of theory, experiments, models and observations

International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the University of Bonn; International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the University of Cologne; FONDECYT [1140099]; U.S. National Science Foundation [AST-1312950]; ERC Advanced Investigator programme DUSTYGAL [321334]; Simons Foundation; NSF [AST-1009452, AST-1445357]; NASA HST from the Space Telescope Science Institute [AR-13906.001]; NASA [NAS5-26555]; Cottrell College Science Award - Research Corporation for Science Advancement; Commonwealth of Australia; National Science Foundation [PLR-1248097]; Kavli Foundation; Gordon and Betty Moore Foundation [GBMF 947]; [PHY-1125897]

/pdf/ism-properties-of-a-massive-dusty-star-forming-galaxy-1ek9ae48gt.pdf

ISM properties of a massive dusty star-forming galaxy discovered at z ∼ 7.

Neutral-atomic and molecular outflows are a common occurrence in galaxies, near and far. They operate over the full extent of their galaxy hosts, from the innermost regions of galactic nuclei to the outermost reaches of galaxy halos. They carry a substantial amount of material that would otherwise have been used to form new stars. These cool outflows may have a profound impact on the evolution of their host galaxies and environments. This article provides an overview of the basic physics of cool outflows, a comprehensive assessment of the observational techniques and diagnostic tools used to characterize them, a detailed description of the best-studied cases, and a more general discussion of the statistical properties of these outflows in the local and distant universe. The remaining outstanding issues that have not yet been resolved are summarized at the end of the review to inspire new research directions.

Cool outflows in galaxies and their implications

NSF Astronomy and Astrophysics Postdocoral Fellowship [AST-1402193]; NASA [NNX13AL16G]; CSA (Canada); NAOC (China); CEA (France); CNES (France); CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC (UK); NASA (USA)

/pdf/l-co-l-fir-relations-with-co-rotational-ladders-of-galaxies-1n8p749gf4.pdf

L '(co)/l-fir relations with co rotational ladders of galaxies across the herschel spire archive

(Ultra) luminous infrared galaxies ((U)LIRGs) are objects characterized by their extreme infrared (8-1000 mu m) luminosities (L-LIRG > 10(11) L-circle dot and L-ULIRG > 10(12) L-circle dot). The Herschel Comprehensive ULIRG Emission Survey (PI: van derWerf) presents a representative flux-limited sample of 29 (U)LIRGs that spans the full luminosity range of these objects (10(11)L(circle dot) <= L-IR <= 10(13)L(circle dot)). With the Herschel Space Observatory, we observe [CII] 157 mu m, [O I] 63 mu m, and [O I] 145 mu m line emission with Photodetector Array Camera and Spectrometer, CO J = 4-3 through J = 13-12, [C I] 370 mu m, and [C I] 609 mu m with SPIRE, and low-J CO transitions with ground-based telescopes. The CO ladders of the sample are separated into three classes based on their excitation level. In 13 of the galaxies, the [O I] 63 mu m emission line is self absorbed. Comparing the CO excitation to the InfraRed Astronomical Satellite 60/100 mu m ratio and to far infrared luminosity, we find that the CO excitation is more correlated to the far infrared colors. We present cooling budgets for the galaxies and find fine-structure line flux deficits in the [C II], [Si II], [O I], and [C I] lines in the objects with the highest far IR fluxes, but do not observe this for CO 4 <= J(upp) <= 13. In order to study the heating of the molecular gas, we present a combination of three diagnostic quantities to help determine the dominant heating source. Using the CO excitation, the CO J = 1-0 linewidth, and the active galactic nucleus (AGN) contribution, we conclude that galaxies with large CO linewidths always have high-excitation CO ladders, and often low AGN contributions, suggesting that mechanical heating is important.

https://publications.lib.chalmers.se/records/fulltext/215467/local_215467.pdf

The herschel comprehensive (u)lirg emission survey (hercules): co ladders, fine structure lines, and neutral gas cooling

Recent advances in far-infrared detector technology have led to increases in raw sensitivity of more than an order of magnitude over previous state-of-the-art detectors. With such sensitivity, photon noise becomes the dominant noise component, even when using cryogenically cooled optics, unless a method of restricting the spectral bandpass is employed. The leading instrument concept features reflecting grating spectrometers to post-disperse the light that has been modulated by a polarizing Fourier transform spectrometer (FTS) onto a detector array, thereby reducing the photon noise on each detector. This paper describes the development of a cryogenic (4 K) reflection grating spectrometer which operates over the wavelength range from 285 µm–500 µm and was used to post-disperse the output from a room-temperature polarizing FTS. Measurements of the grating resolving power and diffraction efficiency are presented as a function of both wavelength and polarization to characterize the instrument performance

Determining the efficiency of a cryogenic far-infrared diffraction grating spectrometer used as a post-dispersing module for a high-resolution spectrometer

I. Veenendaal

Papers

The herschel comprehensive (u)lirg emission survey (hercules): co ladders, fine structure lines, and neutral gas cooling

Determining the efficiency of a cryogenic far-infrared diffraction grating spectrometer used as a post-dispersing module for a high-resolution spectrometer

SPEXone, the multi-angle spectropolarimeter for PACE, adjusted and improved for new space applications