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Start Over Subject infrared astronomy Content Level Research
281. 4FGL sources with IR/Rad associations
ID:
ivo://CDS.VizieR/J/ApJS/248/23
Title:
4FGL sources with IR/Rad associations
Short Name:
J/ApJS/248/23
Date:
09 Nov 2021 09:30:22
Publisher:
CDS
Description:
Associating {gamma}-ray sources to their low-energy counterparts is one of the major challenges of modern {gamma}-ray astronomy. In the context of the Fourth Fermi Large Area Telescope Source Catalog (4FGL), the associations rely mainly on parameters such as apparent magnitude, integrated flux, and angular separation between the {gamma}-ray source and its low-energy candidate counterpart. In this work, we propose a new use of the likelihood ratio (LR) and a complementary supervised learning technique to associate {gamma}-ray blazars in 4FGL, based only on spectral parameters such as the {gamma}-ray photon index, mid-infrared colors, and radio-loudness. In the LR approach, we crossmatch the Wide-field Infrared Survey Explorer Blazar-Like Radio-Loud Sources catalog with 4FGL and compare the resulting candidate counterparts with the sources listed in the {gamma}-ray blazar locus to compute an association probability (AP) for 1138 counterparts. In the supervised learning approach, we train a random forest algorithm with 869 high-confidence blazar associations and 711 fake associations and then compute an AP for 1311 candidate counterparts. A list with all 4FGL blazar candidates of uncertain type associated by our method is provided to guide future optical spectroscopic follow-up observations.
282. FIR bright sources of M83
ID:
ivo://CDS.VizieR/J/MNRAS/432/2182
Title:
FIR bright sources of M83
Short Name:
J/MNRAS/432/2182
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate star formation and dust heating in the compact far-infrared (FIR) bright sources detected in the Herschel maps of M83. We use the source extraction code GETSOURCES to detect and extract sources in the FIR, as well as their photometry in the mid-infrared and H{alpha}. By performing infrared spectral energy distribution fitting and applying an H{alpha}-based star formation rate (SFR) calibration, we derive the dust masses and temperatures, SFRs, gas masses and star formation efficiencies (SFEs). The detected sources lie exclusively on the spiral arms and represent giant molecular associations, with gas masses and sizes of 106-108M{sun} and 200-300pc, respectively. The inferred parameters show little to no radial dependence and there is only a weak correlation between the SFRs and gas masses, which suggests that more massive clouds are less efficient at forming stars. Dust heating is mainly due to local star formation. However, although the sources are not optically thick, the total intrinsic young stellar population luminosity can almost completely account for the dust luminosity. This suggests that other radiation sources also contribute to the dust heating and approximately compensate for the unabsorbed fraction of UV light.
283. FIR spectra of AGNs from Herschel
ID:
ivo://CDS.VizieR/J/ApJS/226/19
Title:
FIR spectra of AGNs from Herschel
Short Name:
J/ApJS/226/19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a coherent database of spectroscopic observations of far-IR fine-structure lines from the Herschel/Photoconductor Array Camera and Spectrometer (PACS) 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{mu}m 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 [OIV]_25.9um_/[OIII]_88um_ versus [NeIII]_15.6um_/[NeII]_12.8um_ 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 [OIV]_25.9um_/[OIII]_88um_ ratios, which are much higher when compared to the predicted values. Finally, the ([NeIII]_15.6um_+[NeII]_12.8um_)/([SIV]_10.5um_+[SIII]_18.7um_) 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<z<4). This study will be addressed by future deep spectroscopic surveys with present and forthcoming facilities such as the James Webb Space Telescope, the Atacama Large Millimeter/submillimeter Array, and the Space Infrared telescope for Cosmology and Astrophysics.
284. First Byurakan Survey Late Type Stars catalog
ID:
ivo://CDS.VizieR/III/246
Title:
First Byurakan Survey Late Type Stars catalog
Short Name:
III/246
Date:
21 Oct 2021
Publisher:
CDS
Description:
The First Byurakan Survey (FBS), also known as the Markarian survey, covers about 17000 sq. deg. It has been used by Markarian and his collaborators to search for UV excess galaxies (see Cat. VII/172), by Abrahamyan and his collaborators to search for late type stars and UV excess or emission line point sources (stars and starlike objects). The identification, classification, and investigation of late type stars and blue stellar objects constitutes the second part of the First Byurakan Survey and is a natural continuation of it. For this second program, at the present time, a catalogue of 1103 blue objects has been built (see Cat. II/223). In a series of 14 papers, referenced in the "References" section below, have been published lists of 1000 late M type and carbon stars, selected on the FBS plates. We have revised and updated this 14 lists with the new data from recently published optical and infrared catalogs to give access to all available data. As a result, the catalog of the First Byurakan Survey (FBS) Late Type Stars, was compiled. In this catalogue are presented high accurate coordinates, proper motions, spectral, photometric and infrared dates about of 995 FBS late M type and carbon stars. Are given cross-identifications of FBS late type stars with their counterparts from the most popular catalogs (2MASS, USNO-B1, NOMAD, UCAC2, GCVS4.2, NSVS, ASAS, IRAS PS and IRAS FS). On the base of 2MASS (J-K) color indices were determined a luminosity classes for 988 of them. For the 55 stars were determined a spectral classes, and for the another 129 were determined a spectral subclasses on the base of DFBS (http://byurakan.phys.uniroma1.it/) These data were not presented in original lists.
285. First Byurakan Survey of Late-Type Stars - v2
ID:
ivo://CDS.VizieR/J/MNRAS/489/2030
Title:
First Byurakan Survey of Late-Type Stars - v2
Short Name:
J/MNRAS/489/2030
Date:
21 Oct 2021
Publisher:
CDS
Description:
A total of 18 lists of the First Byurakan Survey of Late-Type Stars (FBS LTS) were published between 1990 and 2016. The stars were found on FBS low-dispersion spectroscopic plates. A systematic search and selection were carried out on a surface of ~16000deg^2^ on almost the whole area of the FBS. As a result, the "Revised and Updated Catalogue of the First Byurakan Survey of Late-Type Stars" was generated (FBS LTS v1; see Cat. III/266 -- 1045 objects). We present the second version of the catalogue of FBS LTS with new data (FBS LTS v2), comprising 1471 objects. It is a homogeneous and complete data base for high-Galactic-latitude, late-type stars, including M and C types. Since 2007, all FBS low-resolution spectral plates have been digitized. All digitized FBS (DFBS) spectral plates have been analysed with FITSVIEW and SAO IMAGE DS9, and numerous relatively faint LTSs have been discovered. We have performed cross-correlations with DFBS, USNO-B1.0, 2MASS, AllWISE, IRAS PSC/FSC, AKARI, ROSAT BSC/FSC, GCVS, SDSS and added updated SIMBAD data. For numerous new detected objects, we present accurate DSS2 positions, approximate spectral subtypes refined from the DFBS low-dispersion spectra, luminosity classes estimated from 2MASS colours, and available proper motions for 1471 FBS LTSs. The Revised and Updated Catalogue v2 lists a large number of completely new objects, which promises to extend very significantly the census of M giants, faint N-type asymptotic giant branch carbon stars, CH-type carbon giants at high Galactic latitudes, and M dwarfs in the Solar vicinity up to 16.0-17.0mag in the visual. Some important data from Gaia DR2 and supplementary spectra from the Byurakan Astrophysical Observatory 2.6m and LAMOST telescopes are presented.
286. FIRST-2MASS dust-reddened QSO spectra
ID:
ivo://CDS.VizieR/J/ApJ/757/51
Title:
FIRST-2MASS dust-reddened QSO spectra
Short Name:
J/ApJ/757/51
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a sample of 120 dust-reddened quasars identified by matching radio sources detected at 1.4GHz in the Faint Images of the Radio Sky at Twenty Centimeters survey (FIRST) with the near-infrared Two Micron All Sky Survey catalog (2MASS) and color-selecting red sources. Optical and/or near-infrared spectroscopy provide broad wavelength sampling of their spectral energy distributions that we use to determine their reddening, characterized by E(B-V). We demonstrate that the reddening in these quasars is best described by Small-Magellanic-Cloud-like dust. This sample spans a wide range in redshift and reddening (0.1<~z<~3, 0.1<~E(B-V)<~1.5), which we use to investigate the possible correlation of luminosity with reddening. At every redshift, dust-reddened quasars are intrinsically the most luminous quasars. We interpret this result in the context of merger-driven quasar/galaxy co-evolution where these reddened quasars are revealing an emergent phase during which the heavily obscured quasar is shedding its cocoon of dust prior to becoming a "normal" blue quasar. When correcting for extinction, we find that, depending on how the parent population is defined, these red quasars make up <~15%-20% of the luminous quasar population. We estimate, based on the fraction of objects in this phase, that its duration is 15%-20% as long as the unobscured, blue quasar phase.
287. FIRST-2MASS faint sources
ID:
ivo://CDS.VizieR/J/ApJ/607/60
Title:
FIRST-2MASS faint sources
Short Name:
J/ApJ/607/60
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have constructed a sample of bright near-infrared sources that are detected at radio wavelengths but undetected on the first-generation Palomar Observatory Sky Survey (POSSI) plates in order to search for a population of dust-obscured quasars. Optical and infrared spectroscopic follow-up of the sample has led to the discovery of 17 heavily reddened quasars (B-K>6.5), 14 of which are reported here for the first time. This has allowed us to define a region in the R-K, J-K color plane in which 50% of the radio-selected objects are highly reddened quasars. We compare the surface density of this previously overlooked population to that of ultraviolet-excess radio-selected quasars, finding that they make up ~20% of the total quasar population for K<~15.5.
288. FIRST-2MASS red quasar survey
ID:
ivo://CDS.VizieR/J/ApJ/667/673
Title:
FIRST-2MASS red quasar survey
Short Name:
J/ApJ/667/673
Date:
21 Oct 2021
Publisher:
CDS
Description:
Combining radio observations with optical and infrared color selection, demonstrated in our pilot study to be an efficient selection algorithm for finding red quasars, we have obtained optical and infrared spectroscopy for 120 objects in a complete sample of 156 candidates from a sky area of 2716deg^2^.
289. First quadrant IRDCs in CS(2-1) with Mopra
ID:
ivo://CDS.VizieR/J/ApJ/764/102
Title:
First quadrant IRDCs in CS(2-1) with Mopra
Short Name:
J/ApJ/764/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
Infrared dark clouds (IRDCs) are believed to host the earliest stages of high-mass star and cluster formation. Because O stars typically travel short distances over their lifetimes, if IRDCs host the earliest stages of high-mass star formation then these cold, dense molecular clouds should be located in or near the spiral arms in the Galaxy. The Galactic distribution of a large sample of IRDCs should therefore provide information on Galactic structure. Moreover, determination of distances enables mass and luminosity calculations. We have observed a large sample of IRDC candidates in the first Galactic quadrant in the dense gas tracer CS(2-1) using the Mopra telescope in order to determine kinematic distances from the molecular line velocities. We find that the IRDCs are concentrated around a Galactocentric distance of ~4.5kpc, agreeing with the results of Simon et al. (2006, J/ApJ/653/1325). This distribution is consistent with the location of the Scutum-Centaurus spiral arm. The group of IRDCs near the Sun in the first quadrant detected in ^13^CO(1-0) in Simon et al. is not detected in the CS data. This discrepancy arises from the differences in the critical densities between the ^13^CO(1-0) and CS(2-1) lines. We determine that the Midcourse Space Experiment selected IRDCs are not a homogeneous population, and ^13^CO(1-0) traces a population of IRDCs with lower column densities and lower 1.1 mm flux densities in addition to more dense IRDCs detected in CS. Masses of the first quadrant IRDCs are calculated from ^13^CO(1-0) maps. We find a strong peak in the Galactocentric IRDC mass surface density distribution at R_Gal_~4.5kpc.
290. Five Herbig-Haro objects SOFIA/FIFI-LS images
ID:
ivo://CDS.VizieR/J/A+A/642/A216
Title:
Five Herbig-Haro objects SOFIA/FIFI-LS images
Short Name:
J/A+A/642/A216
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present SOFIA/FIFI-LS observations of five prototypical, low-mass Class I outflows (HH111, SVS13, HH26, HH34, HH30) in the far-infrared [OI]63um and [OI]145um transitions. Spectroscopic [OI]63um,145um maps enable us to study the spatial extent of warm, low-excitation atomic gas within outflows driven by Class I protostars. These [OI] maps may potentially allow us to measure the mass-loss rates (dM/dt_jet_) of this warm component of the atomic jet. A fundamental tracer of warm (i.e. T~500-1500K), low-excitation atomic gas is the [OI]63um emission line, which is predicted to be the main coolant of dense dissociative J-type shocks caused by decelerated wind or jet shocks associated with protostellar outflows. Under these conditions, the [O I]63um line can be directly connected to the instantaneous mass ejection rate.Thus, by utilising spectroscopic [OI]63um maps, we wish to determine the atomic mass flux rate dM/dt_jet_ ejected from our target outflows. Strong [OI]63um emission is detected at the driving sources HH111IRS, HH34IRS, SVS13, as well as at the bow shock region, HH7. The detection of the [OI]63um line at HH26A and HH8/HH10 can be attributed to jet deflection regions. The far-infrared counterpart of the optical jet is detected in [OI]63um only for HH111, but not for HH34. We interpret the [OI]63um emission at HH111IRS, HH34IRS, and SVS13 to be coming primarily from a decelerated wind shock, whereas multiple internal shocks within the HH111 jet may cause most of the [O I]63um emission seen there. At HH30, no [O I]63um,145um was detected. The [OI]145um line detection is at noise level almost everywhere in our obtained maps. The observed outflow rates of our Class I sample are to the order of dM/dt_jet_~10^-6^M_{sun}_/yr, if proper shock conditions prevail. Independent calculations connecting the [OI]63um line luminosity and observable jet parameters with the mass-loss rate are consistent with the applied shock model and lead to similar mass-loss rates. Wediscuss applicability and caveats of both methods. High-quality spectroscopic [OI]63um maps of protostellar outflows at the jet driving source potentially allow a clear determination of the mass ejection rate.