- ID:
- ivo://CDS.VizieR/J/A+A/595/A43
- Title:
- Photometry of 119 HII regions in M33
- Short Name:
- J/A+A/595/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the dust properties of a sample of HII regions in the Local Group Galaxy M 33 presenting different spatial configurations between stars, gas, and dust. We obtain the spectral energy distribution (SED) from the UV (GALEX) to the far IR (Herschel) performing photometry in each HII region of the sample. We model the SED using DustEM tool to understand the dust evolution in different environments. The fraction of very small grains can be affected by the conditions of the interstellar environment: strong shocks existing in the interior of the most luminous HII regions can lead to fragmentation of big grains into smaller ones, while the more evolved objects provide a more quiescent environment where reformation of dust big grains might occur.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/473/149
- Title:
- Photometry of sources in IRAS 16362-4845 cluster
- Short Name:
- J/A+A/473/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IRAS 16362-4845 star-forming site in the RCW 108 complex contains an embedded compact cluster that includes some massive O-type stars. Star formation in the complex, and in particular in IRAS 16362-4845, has been proposed to be externally triggered by the action of NGC 6193. We present a photometric study of the IRAS 16362-4845 cluster sensitive enough to probe the massive brown dwarf regime. In particular, we try to verify an apparent scarcity of solar-type and low-mass stars reported in a previous paper (Comeron et al., 2005A&A...433..955C).
- ID:
- ivo://CDS.VizieR/J/MNRAS/338/508
- Title:
- Photometry+spectroscopy of UCM galaxies
- Short Name:
- J/MNRAS/338/508
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the integrated properties of the stellar populations in the Universidad Complutense de Madrid (UCM) Survey of H{alpha}-selected galaxies. In this paper, the first of a series, we describe in detail the techniques developed to model star-forming galaxies using a mixture of stellar populations, and taking into account the observational uncertainties. We assume a recent burst of star formation superimposed on a more evolved population. The effects of the nebular continuum, line emission and dust attenuation are taken into account. We also test different model assumptions, including the choice of specific evolutionary synthesis model, initial mass function, star formation scenario and the treatment of dust extinction. Quantitative tests are applied to determine how well these models fit our multiwavelength observations for the UCM sample. Our observations span the optical and near-infrared, including both photometric and spectroscopic data. Our results indicate that extinction plays a key role in this kind of study, revealing that low- and high-obscured objects may require very different extinction laws and must be treated differently. We also demonstrate that the UCM Survey galaxies are best described by a short burst of star formation occurring within a quiescent galaxy, rather than by continuous star formation. A detailed discussion on the inferred parameters, such as the age, burst strength, metallicity, star formation rate, extinction and total stellar mass for individual objects, is presented in Paper II of this series.
- ID:
- ivo://CDS.VizieR/J/A+A/596/A100
- Title:
- Planck high-z source candidates catalog (PHZ)
- Short Name:
- J/A+A/596/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck mission, thanks to its large frequency range and all-sky coverage, has a unique potential for systematically detecting the brightest, and rarest, submillimetre sources on the sky, including distant objects in the high-redshift Universe traced by their dust emission. A novel method, based on a component-separation procedure using a combination of Planck and IRAS data, has been validated and characterized on numerous simulations, and applied to select the most luminous cold submillimetre sources with spectral energy distributions peaking between 353 and 857GHz at 5' resolution. A total of 2151 Planck high-z source candidates (the PHZ) have been detected in the cleanest 26% of the sky, with flux density at 545GHz above 500mJy. Embedded in the cosmic infrared background close to the confusion limit, these high-z candidates exhibit colder colours than their surroundings, consistent with redshifts z>2, assuming a dust temperature of Txgal=35K and a spectral index of {beta}xgal=1.5. Exhibiting extremely high luminosities, larger than 10^14^L_{sun}_, the PHZ objects may be made of multiple galaxies or clumps at high redshift, as suggested by a first statistical analysis based on a comparison with number count models. Furthermore, first follow-up observations obtained from optical to submillimetre wavelengths, which can be found in companion papers, have confirmed that this list consists of two distinct populations. A small fraction (around 3%) of the sources have been identified as strongly gravitationally lensed star-forming galaxies at redshift 2 to 4, while the vast majority of the PHZ sources appear as overdensities of dusty star-forming galaxies, having colours consistent with being at z>2, and may be considered as proto-cluster candidates. The PHZ provides an original sample, which is complementary to the Planck Sunyaev-Zeldovich Catalogue (PSZ2); by extending the population of virialized massive galaxy clusters detected below z<1.5 through their SZ signal to a population of sources at z>1.5, the PHZ may contain the progenitors of today's clusters. Hence the Planck list of high-redshift source candidates opens a new window on the study of the early stages of structure formation, particularly understanding the intensively star-forming phase at high-z.
- ID:
- ivo://CDS.VizieR/J/ApJS/123/219
- Title:
- Planetary Nebulae in NRAO VLA Sky Survey
- Short Name:
- J/ApJS/123/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to construct a sample of planetary nebulae (PNe) unbiased by dust extinction, we first selected the 1358 sources in the IRAS Point Source Catalog north of J2000 declination DE=-40{deg} having measured S(25{mu}m)>=1 Jy and colors characteristic of PNe: detections or upper limits consistent with both S(12{mu}m)<=0.35S(25{mu}m) and S(25{mu}m)>=0.35S(60{mu}m). The majority are radio-quiet contaminating sources such as asymptotic giant branch stars. Free-free emission from genuine PNe should make them radio sources. The 1.4 GHz NRAO VLA Sky Survey (NVSS) images and source catalog were used to reject radio-quiet mid-infrared sources. We identified 454 IRAS sources with radio sources brighter than S~2.5 mJy/beam (equivalent to T~0.8K in the 45" FHWM NVSS beam) by positional coincidence. They comprise 332 known PNe in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae and 122 candidate PNe, most of which lie at very low Galactic latitudes. Exploratory optical spectroscopic observations suggest that most of these candidates are indeed PNe optically dimmed by dust extinction, although some contamination remains from H II regions, Seyfert galaxies, etc. Furthermore, the NVSS failed to detect only 4% of the known PNe in our infrared sample. Thus it appears that radio selection can greatly improve the reliability of PN candidate samples without sacrificing completeness.
- ID:
- ivo://CDS.VizieR/J/A+A/535/A90
- Title:
- POKER (P. Of k EstimatoR) code
- Short Name:
- J/A+A/535/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the implementation of an angular power spectrum estimator in the at sky approximation. POKER (P. Of k EstimatoR) is based on the MASTER algorithm developped by Hivon and collaborators in the context of CMB anisotropy. It works entirely in discrete space and can be applied to arbitrary high angular resolution maps. It is therefore particularly suitable for current and future infrared to sub-mm observations of diffuse emission, whether Galactic or cosmological.
- ID:
- ivo://CDS.VizieR/J/A+A/569/L1
- Title:
- Polarization hole in a starless core
- Short Name:
- J/A+A/569/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to investigate the polarization properties of a starless core in a very early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to investigate how the polarization degree and angle correlate with the cloud and core gas. We use optical, near infrared and submillimeter polarization observations toward the starless object Pipe-109 in the Pipe nebula. Our data cover a physical scale range of 0.08 to 0.4pc, comprising the dense gas, envelope and the surrounding cloud. The cloud polarization is well traced by the optical data. The near infrared polarization is produced by a mixed population of grains from the core border and the cloud gas. The optical and near infrared polarization toward the cloud reach the maximum possible value and saturate with respect to the visual extinction. The core polarization is predominantly traced by the submillimeter data and have a steep decrease with respect to the visual extinction. Modeling of the submillimeter polarization indicates a magnetic field main direction projected onto the plane-of-sky and loss of grain alignment for densities higher than 6x10^4^cm^-3^ (or A_V_>30mag). Pipe-109 is immersed in a magnetized medium, with a very ordered magnetic field. The absence of internal source of radiation significantly affects the polarization efficiencies in the core, creating a polarization hole at the center of the starless core. This result supports the theory of dust grain alignment via radiative torques.
- ID:
- ivo://CDS.VizieR/J/ApJ/741/21
- Title:
- Polarization of stars in Taurus
- Short Name:
- J/ApJ/741/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present maps of the plane-of-sky magnetic field within two regions of the Taurus molecular cloud: one in the dense core L1495/B213 filament and the other in a diffuse region to the west. The field is measured from the polarization of background starlight seen through the cloud. In total, we measured 287 high-quality near-infrared polarization vectors in these regions. In L1495/B213, the percent polarization increases with column density up to A_V_~9mag, the limits of our data. The radiative torques model for grain alignment can explain this behavior, but models that invoke turbulence are inconsistent with the data. We also combine our data with published optical and near-infrared polarization measurements in Taurus. Using this large sample, we estimate the strength of the plane-of-sky component of the magnetic field in nine subregions. This estimation is done with two different techniques that use the observed dispersion in polarization angles. Our values range from 5 to 82uG and tend to be higher in denser regions. In all subregions, the critical index of the mass-to-magnetic flux ratio is sub-unity, implying that Taurus is magnetically supported on large scales (~2pc). Within the region observed, the B213 filament takes a sharp turn to the north and the direction of the magnetic field also takes a sharp turn, switching from being perpendicular to the filament to becoming parallel. This behavior can be understood if we are observing the rim of a bubble. We argue that it has resulted from a supernova remnant associated with a recently discovered nearby gamma-ray pulsar.
- ID:
- ivo://CDS.VizieR/J/ApJ/733/69
- Title:
- Polarized DRAO sources
- Short Name:
- J/ApJ/733/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Dominion Radio Astrophysical Observatory Deep Field polarization study has been matched with the Spitzer Wide-Area Infrared Extragalactic Survey of the European Large Area Infrared Space Observatory Survey North 1 field. We have used Very Large Array observations with a total intensity rms of 87uJy/beam to match SWIRE counterparts to the radio sources. Infrared color analysis of our radio sample shows that the majority of polarized sources are elliptical galaxies with an embedded active galactic nucleus. Using available redshift catalogs, we found 429 radio sources of which 69 are polarized with redshifts in the range of 0.04<z<3.2. We find no correlation between redshift and percentage polarization for our sample. However, for polarized radio sources, we find a weak correlation between increasing percentage polarization and decreasing luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJ/633/871
- Title:
- Positions and photometry of HII knots in M51
- Short Name:
- J/ApJ/633/871
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-ultraviolet to far-infrared images of the nearby galaxy NGC 5194 (M51a), from a combination of space-based (Spitzer, GALEX, and Hubble Space Telescope) and ground-based data, are used to investigate local and global star formation and the impact of dust extinction. The Spitzer data provide unprecedented spatial detail in the infrared, down to sizes 500 pc at the distance of NGC 5194. The multiwavelength set is used to trace the relatively young stellar populations, the ionized gas, and the dust absorption and emission in HII-emitting knots, over 3 orders of magnitude in wavelength range.
