- ID:
- ivo://CDS.VizieR/J/A+A/580/A68
- Title:
- 3D observations of S 140
- Short Name:
- J/A+A/580/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The objective of this work is to study in detail the temperatures of dust and gas in the photon-dominated region S140, especially around the deeply embedded infrared sources IRS1-3 and at the ionization front. We derive the dust temperature and column density by combining Herschel PACS continuum observations with SOFIA observations at 37um and SCUBA data at 450um. We model these observations using simple greybody fits and the DUSTY radiative transfer code. For the gas analysis we use RADEX to model the CO 1-0, CO 2-1, ^13^CO 1-0 and C^18^O 1-0 emission lines mapped with the IRAM-30m telescope over a 4' field. Around IRS 1-3, we use HIFI observations of single-points and cuts in CO 9-8, ^13^CO 10-9 and C^18^O 9-8 to constrain the amount of warm gas
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Search Results
212. DRaGONS survey
- ID:
- ivo://CDS.VizieR/J/ApJ/649/63
- Title:
- DRaGONS survey
- Short Name:
- J/ApJ/649/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the Distant Radio Galaxies Optically Non-detected in the SDSS (DRaGONS) survey. Using a novel selection technique for identifying high-redshift radio galaxy (HzRG) candidates, a large sample is compiled using bright (S_1.4GHz_>100mJy) radio sources from the FIRST survey having no optical counterpart in the SDSS. Near-IR K-band imaging for 96 targets allows preliminary identification of HzRG candidates through the well-known K-z relation, for subsequent spectroscopic observation. We measure magnitudes brighter than K~19.5 for 70 of the 96, and limiting magnitudes for the remainder. Redshifts based on a linear fit to the K-z diagram give a mean <z>=2.5 and median z=2.0, showing that this method should be efficient at identifying a large number of HzRGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/790/124
- Title:
- Dust and gas physics of the GOALS sample
- Short Name:
- J/ApJ/790/124
- Date:
- 13 Dec 2021 06:47:30
- Publisher:
- CDS
- Description:
- The Great Observatories All-sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here, we present the results of a multi-component, spectral decomposition analysis of the low-resolution mid-infrared (MIR) Spitzer Infrared Spectrograph spectra from 5-38 {mu}m of 244 LIRG nuclei. The detailed fits and high-quality spectra allow for characterization of the individual polycyclic aromatic hydrocarbon (PAH) features, warm molecular hydrogen emission, and optical depths for both silicate dust grains and water ices. We find that starbursting LIRGs, which make up the majority of the GOALS sample, are very consistent in their MIR properties (i.e., {tau}_9.7 {mu}m_, {tau}_ice_, neon line ratios, and PAH feature ratios). However, as their EQW_6.2 {mu}m_decreases, usually an indicator of an increasingly dominant active galactic nucleus (AGN), LIRGs cover a larger spread in these MIR parameters. The contribution from PAH emission to the total IR luminosity (L(PAH)/L(IR)) in LIRGs varies from 2%-29% and LIRGs prior to their first encounter show significantly higher L(PAH)/L(IR) ratios on average. We observe a correlation between the strength of the starburst (represented by IR8 = L_IR_/L_8 {mu}m_) and the PAH fraction at 8 {mu}m but no obvious link between IR8 and the 7.7 to 11.3 PAH ratio, suggesting that the fractional photodissociation region (PDR) emission, and not the overall grain properties, is associated with the rise in IR8 for galaxies off the starburst main sequence. We detect crystalline silicate features in ~6% of the sample but only in the most obscure sources (s_9.7 {mu}m_< -1.24). Ice absorption features are observed in ~11% (56%) of GOALS LIRGs (ULIRGs) in sources with a range of silicate depths. Most GOALS LIRGs have L(H_2_)/L(PAH) ratios elevated above those observed for normal star-forming galaxies and exhibit a trend for increasing L(H_2_)/L(PAH) ratio with increasing L(H_2_). While star formation appears to be the dominant process responsible for exciting the H_2_ in most of the GOALS galaxies, a subset of LIRGs (~10%) shows excess H_2_emission that is inconsistent with PDR models and may be excited by shocks or AGN-induced outflows.
- ID:
- ivo://CDS.VizieR/J/A+A/447/221
- Title:
- Dust continuum emission from IRAS sources
- Short Name:
- J/A+A/447/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In an ongoing effort to identify and study high-mass protostellar candidates we have observed in various tracers a sample of 235 sources selected from the IRAS Point Source Catalog (Cat. <II/125>), mostly with delta<-30{deg}, with the SEST antenna at millimeter wavelengths. The sample contains 142 Low sources and 93 High, which are believed to be in different evolutionary stages. Both sub-samples have been studied in detail by comparing their physical properties and morphologies.
- ID:
- ivo://CDS.VizieR/J/ApJ/744/150
- Title:
- Dust-obscured galaxies (DOGs) at z=~2
- Short Name:
- J/ApJ/744/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z~2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M_*_) of two populations of Spitzer-selected ULIRGs that have extremely red R-[24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6um associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M_*_ by applying Charlot & Bruzual (1991ApJ...367..126C) stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/116
- Title:
- Dust-obscured galaxies in the local universe
- Short Name:
- J/ApJ/769/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Wide-field Infrared Survey Explorer (WISE), AKARI, and Galaxy Evolution Explorer (GALEX) data to select local analogs of high-redshift (z~2) dust obscured galaxies (DOGs). We identify 47 local DOGs with S_12{mu}m_/S_0.22{mu}m_>=892 and S_12{mu}m_>20mJy at 0.05<z<0.08 in the Sloan Digital Sky Survey data release 7. The infrared (IR) luminosities of these DOGs are in the range 3.4x10^10^(L_{sun}_)<~L_IR_<~7.0x10^11^(L_{sun}_) with a median L_IR_ of 2.1x10^11^(L_{sun}_). We compare the physical properties of local DOGs with a control sample of galaxies that have lower S_12{mu}m_/S_0.22{mu}m_ but have similar redshift, IR luminosity, and stellar mass distributions. Both WISE 12{mu}m and GALEX near-ultraviolet (NUV) flux densities of DOGs differ from the control sample of galaxies, but the difference is much larger in the NUV. Among the 47 DOGs, 36%+/-7% have small axis ratios in the optical (i.e., b/a<0.6), larger than the fraction among the control sample (17%+/-3%). There is no obvious sign of interaction for many local DOGs. No local DOGs have companions with comparable optical magnitudes closer than ~50kpc. The large- and small-scale environments of DOGs are similar to the control sample. Many physical properties of local DOGs are similar to those of high-z DOGs, even though the IR luminosities of local objects are an order of magnitude lower than for the high-z objects: the presence of two classes (active galactic nuclei- and star formation-dominated) of DOGs, abnormal faintness in the UV rather than extreme brightness in the mid-IR, and diverse optical morphology. These results suggest a common underlying physical origin of local and high-z DOGs. Both seem to represent the high-end tail of the dust obscuration distribution resulting from various physical mechanisms rather than a unique phase of galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A121
- Title:
- Dust properties in galaxies
- Short Name:
- J/A+A/582/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we aim to provide a consistent analysis of the dust properties from metal-poor to metal-rich environments by linking them to fundamental galactic parameters. We consider two samples of galaxies: the Dwarf Galaxy Survey (DGS) and the Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel (KINGFISH), totalling 109 galaxies, spanning almost 2dex in metallicity. We collect infrared (IR) to submillimetre (submm) data for both samples and present the complete data set for the DGS sample. We model the observed spectral energy distributions (SED) with a physically-motivated dust model to access the dust properties: dust mass, total-IR luminosity, polycyclic aromatic hydrocarbon (PAH) mass fraction, dust temperature distribution, and dust-to-stellar mass ratio. Using a different SED model (modified black body), different dust composition (amorphous carbon in lieu of graphite), or a different wavelength coverage at submm wavelengths results in differences in the dust mass estimate of a factor two to three, showing that this parameter is subject to non-negligible systematic modelling uncertainties. We find half as much dust with the amorphous carbon dust composition. For eight galaxies in our sample, we find a rather small excess at 500{mu}m (<=1.5{sigma}). We find that the dust SED of low-metallicity galaxies is broader and peaks at shorter wavelengths compared to more metal-rich systems, a sign of a clumpier medium in dwarf galaxies. The PAH mass fraction and dust temperature distribution are found to be driven mostly by the specific star formation rate, sSFR, with secondary effects from metallicity. The correlations between metallicity and dust mass or total-IR luminosity are direct consequences of the stellar mass-metallicity relation. The dust-to-stellar mass ratios of metal-rich sources follow the well-studied trend of decreasing ratio for decreasing sSFR. The relation is more complex for low-metallicity galaxies with high sSFR, and depends on the chemical evolutionary stage of the source (i.e. gas-to-dust mass ratio). Dust growth processes in the ISM play a key role in the dust mass build-up with respect to the stellar content at high sSFR and low metallicity. We conclude that the evolution of the dust properties from metal-poor to metal-rich galaxies derives from a complex interplay between star formation activity, stellar mass, and metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/829/78
- Title:
- Dust properties of major-merger galaxy pairs
- Short Name:
- J/ApJ/829/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of dust properties of a sample of close major-merger galaxy pairs selected by Ks magnitude and redshift. The pairs represent the two populations of spiral-spiral (S+S) and mixed morphology spiral-elliptical (S+E). The Code Investigating GALaxy Emission (CIGALE) software is used to fit dust models to the Two Micron All Sky Survey, Wide-Field Infrared Survey Explorer, and Herschel flux density measurements, and to derive the parameters describing the polycyclic aromatic hydrocarbons contribution, interstellar radiation field, and photodissociation regions. Model fits verify our previous Spitzer Space Telescope analysis that S+S and S+E pairs do not have the same level of enhancement of star formation and differ in dust composition.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/96
- Title:
- Dusty star-forming galaxies with LABOCA 870um obs.
- Short Name:
- J/ApJ/862/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present images obtained with LABOCA of a sample of 22 galaxies selected via their red Herschel SPIRE colors. We aim to see if these luminous, rare, and distant galaxies are signposting dense regions in the early universe. Our 870{mu}m survey covers an area of ~1deg^2^ down to an average rms of 3.9mJy/beam, with our five deepest maps going 2x deeper still. We catalog 86 dusty star-forming galaxies (DSFGs) around our "signposts," detected above a significance of 3.5{sigma}. This implies a 100+/-30% overdensity of S_870_>8.5mJy (or L_FIR_=6.7x10^12^-2.9x10^13^L_{sun}_) DSFGs, excluding our signposts, when comparing our number counts to those in "blank fields." Thus, we are 99.93% confident that our signposts are pinpointing overdense regions in the universe, and 95% [50%] confident that these regions are overdense by a factor of at least >=1.5x[2x]. Using template spectral energy distributions (SEDs) and SPIRE/LABOCA photometry, we derive a median photometric redshift of z=3.2+/-0.2 for our signposts, with an inter-quartile range of z=2.8-3.6, somewhat higher than expected for 850{mu}m selected galaxies. We constrain the DSFGs that are likely responsible for this overdensity to within |{delta}_z_|<=0.65 of their respective signposts. These "associated" DSFGs are radially distributed within (physical) distances of 1.6+/-0.5Mpc from their signposts, have median star formation rates (SFRs) of ~(1.0+/-0.2)x10^3^M_{sun}_/yr (for a Salpeter stellar initial mass function) and median gas reservoirs of ~1.7x10^11^M_{sun}_. These candidate protoclusters have average total SFRs of at least ~(2.3+/-0.5)x10^3^M_{sun}_/yr and space densities of 9x10^-7^Mpc^-3^, consistent with the idea that their constituents may evolve to become massive early-type galaxies in the centers of the rich galaxy clusters we see today.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A44
- Title:
- Dwarfs, giants and supergiants Equivalent widths
- Short Name:
- J/A+A/641/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar population studies in the infrared (IR) wavelength range have two main advantages with respect to the optical regime: they probe different populations, because most of the light in the IR comes from redder and generally older stars and allow us to see through dust because the IR light is less affected by extinction. Our project investigates the sensitivity of various spectral features in the 1-5um wavelength range to the physical properties of stars (Teff, [Fe/H], logg) and aims to objectively define spectral indices that can characterize age and metallicity of unresolved stellar populations. We implemented a method that uses derivatives of the indices as functions of Teff, [Fe/H] of log g across the entire available wavelength range to reveal the most sensitive indices to these parameters and the ranges in which these indices work. Here, we complement the previous work in the I and K bands reporting a new system for Y, J, H and L atmospheric windows. We list the equivalent widths of these indices for the Infrared Telescope Facility (IRTF) spectral library stars.