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14981. Sub-mm observations in Extended Chandra DFS
ID:
ivo://CDS.VizieR/J/MNRAS/411/505
Title:
Sub-mm observations in Extended Chandra DFS
Short Name:
J/MNRAS/411/505
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a joint analysis of the overlapping Balloon-borne Large Aperture Submillimetre Telescope (BLAST) 250, 350, 500um, and LABOCA 870um observations [from the LABOCA ECDFS Submm Survey (LESS) survey] of the Extended Chandra Deep Field-South. Out to z~3, the BLAST filters sample near the peak wavelength of thermal far-infrared (FIR) emission from galaxies (rest-frame wavelengths ~60-200um), primarily produced by dust heated through absorption in star-forming clouds. However, identifying counterparts to individual BLAST peaks is very challenging, given the large beams [full-width at half-maximum (FWHM) 36-60 arcsec]. In contrast, the ground-based 870um observations have a significantly smaller 19 arcsec FWHM beam, and are sensitive to higher redshifts (z~1-5, and potentially beyond) due to the more favourable negative K-correction. We use the LESS data, as well as deep Spitzer and VLA imaging, to identify 118 individual sources that produce significant emission in the BLAST bands.
14982. Submm observations in gravitational lenses
ID:
ivo://CDS.VizieR/J/MNRAS/384/1611
Title:
Submm observations in gravitational lenses
Short Name:
J/MNRAS/384/1611
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have conducted a submillimetre mapping survey of faint, gravitationally lensed sources, where we have targeted 12 galaxy clusters and additionally the New Technology Telescope (NTT) Deep Field. The total area surveyed is 71.5arcmin^2^ in the image plane; correcting for gravitational lensing, the total area surveyed is 40arcmin^2^ in the source plane for a typical source redshift z>>2.5. In the deepest maps, an image plane depth of 1{sigma} rms ~0.8mJy is reached. This survey is the largest survey to date to reach such depths. In total 59 sources were detected, including three multiply imaged sources. The gravitational lensing makes it possible to detect sources with flux density below the blank field confusion limit. The lensing-corrected fluxes range from 0.11 to 19mJy. After correcting for multiplicity, there are 10 sources with fluxes <2mJy of which seven have submJy fluxes, doubling the number of such sources known. Number counts are determined below the confusion limit. At 1mJy, the integrated number count is ~10^4^deg^-2^, and at 0.5mJy it is ~2x10^4^deg^-2^. Based on the number counts, at a source plan flux limit of 0.1mJy, essentially all of the 850-m background emission has been resolved. The dominant contribution (>50 per cent) to the integrated background arises from sources with fluxes S850 between 0.4 and 2.5mJy, while the bright sources S850>6mJy contribute only 10 per cent.
14983. Sub-mm observations of IRS43 and IRS63
ID:
ivo://CDS.VizieR/J/A+A/559/A82
Title:
Sub-mm observations of IRS43 and IRS63
Short Name:
J/A+A/559/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
A fundamental part of the study of star formation is to place young stellar objects in an evolutionary sequence. Establishing a robust evolutionary classification scheme allows us not only to understand how the Sun was born but also to predict what kind of main sequence star a given protostar will become. Traditionally, low-mass young stellar objects are classified according to the shape of their spectral energy distributions. Such methods are, however, prone to misclassification due to degeneracy and do not constrain the temporal evolution. More recently, young stellar objects have been classified based on envelope, disk, and stellar masses determined from resolved images of their continuum and line emission at submillimeter wavelengths. Through detailed modeling of two Class I sources, we aim at determining accurate velocity profiles and explore the role of freeze-out chemistry in such objects. We present new Submillimeter Array observations of the continuum and HCO^+^ line emission at 1.1mm toward two protostars, IRS 63 and IRS 43 in the Ophiuchus star forming region. The sources were modeled in detail using dust radiation transfer to fit the SED and continuum images and line radiation transfer to produce synthetic position-velocity diagrams. We used a chi^2^ search algorithm to find the best model fit to the data and to estimate the errors in the model variables. Our best fit models present disk, envelope, and stellar masses, as well as the HCO^+^ abundance and inclination of both sources. We also identify a ring structure with a radius of about 200AU in IRS 63. Conclusions. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43.
14984. Sub-mm observations of the HDF
ID:
ivo://CDS.VizieR/J/MNRAS/344/887
Title:
Sub-mm observations of the HDF
Short Name:
J/MNRAS/344/887
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an extended analysis of the Submillimetre Common User Bolometer Array (SCUBA) observations of the Hubble Deep Field (HDF), expanding the areal coverage of the Hughes et al. (1998Natur.394..241H) study by a factor of ~1.8 and containing at least three further sources in addition to the five in that study. We also announce the public release of the reduced data products. The map is the deepest ever made in the submillimetre (submm), obtained in excellent conditions (median 850-{mu}m optical depth of 0.16).
14985. submm point sources from the Archeops experiment
ID:
ivo://CDS.VizieR/J/A+A/481/411
Title:
submm point sources from the Archeops experiment
Short Name:
J/A+A/481/411
Date:
21 Oct 2021
Publisher:
CDS
Description:
Archeops is a balloon-borne experiment, mainly designed to measure the Cosmic Microwave Background (CMB) temperature anisotropies at high angular resolution (~12 arcminutes). By-products of the mission are shallow sensitivity maps over a large fraction of the sky (about 30 %) in the millimetre and submillimetre range at 143, 217, 353 and 545GHz. From these maps, we produce a catalog of bright submillimetre point sources. We present in this paper the processing and analysis of the Archeops point sources. Redundancy across detectors is the key factor allowing us to distinguish glitches from genuine point sources in the 20 independent maps. We look at the properties of the most reliable point sources, totalling 304. Fluxes range from 1 to 10000Jy (at the frequencies covering 143 to 545GHz). All sources are either planets (2) or of galactic origin. The longitude range is from 75 to 198-degrees. Some of the sources are associated with the well-known Lynds Nebulae and HII compact regions in the galactic plane. A large fraction of the sources have an IRAS counterpart. Except for Jupiter, Saturn, the Crab and Cas A, all sources show a dust-emission-like modified blackbody emission spectrum. Temperatures cover a range from 7 to 27K. For the coldest sources (T<10K), a steep nu^beta^ emissivity law is found with a surprising beta~3 to 4. An inverse relationship between T and beta is observed. The number density of sources at 353GHz with flux brighter than 100Jy is of the order of 1 per degree of Galactic longitude. These sources will provide a strong check for the calibration of the Planck HFI focal plane geometry as a complement to planets. These very cold sources observed by Archeops should be prime targets for mapping observations by the Akari and Herschel space missions and ground-based observatories.
14986. Submm polarization of Galactic clouds
ID:
ivo://CDS.VizieR/J/ApJS/201/13
Title:
Submm polarization of Galactic clouds
Short Name:
J/ApJS/201/13
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Hertz and SCUBA polarimeters, working at 350um and 850um, respectively, have measured the polarized emission in scores of Galactic clouds. Of the clouds in each data set, 17 were mapped by both instruments with good polarization signal-to-noise ratios. We present maps of each of these 17 clouds comparing the dual-wavelength polarization amplitudes and position angles at the same spatial locations.
14987. Sub-stellar birth rate from UKIDSS
ID:
ivo://CDS.VizieR/J/MNRAS/430/1171
Title:
Sub-stellar birth rate from UKIDSS
Short Name:
J/MNRAS/430/1171
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new sample of mid-L to mid-T dwarfs with effective temperatures of 1100-1700K selected from the UKIDSS Large Area Survey (LAS) and confirmed with infrared spectra from X-shooter/Very Large Telescope. This effective temperature range is especially sensitive to the formation history of Galactic brown dwarfs and allows us to constrain the form of the sub-stellar birth rate, with sensitivity to differentiate between a flat (stellar like) birth rate and an exponentially declining form. We present the discovery of 63 new L and T dwarfs from the UKIDSS LAS DR7, including the identification of 12 likely unresolved binaries, which form the first complete sub-set from our programme, covering 495 square degrees of sky, complete to J=18.1. We compare our results for this sub-sample with simulations of differing birth rates for objects of masses 0.10-0.03M_{sun}_ and ages 1-10Gyr. We find that the more extreme birth rates (e.g. a halo type form) can likely be excluded as the true form of the birth rate. In addition, we find that although there is substantial scatter we find a preference for a mass function, with a power-law index {alpha} in the range -1<{alpha}<0 that is consistent (within the errors) with the studies of late T dwarfs.
14988. Sub-stellar companions in Taurus
ID:
ivo://CDS.VizieR/J/ApJ/799/155
Title:
Sub-stellar companions in Taurus
Short Name:
J/ApJ/799/155
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ~3M_{sun}_ and low-mass stars at ~0.2M_{sun}_. We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ~2M_Jup_. The inferred multiplicity frequency within our sensitivity limits between ~10-1500AU is 26.3_-4.9_^+6.6^%. Applying a completeness correction, 62%+/-14% of all Taurus stars between 0.7 and 1.4M_{sun}_ appear to be multiple. Higher order multiples were found in 1.8_-1.5_^+4.2^% of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ~3.5%-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ~2Myr and ~20Myr, respectively.
14989. (Sub)Stellar companions of exoplanet hosts
ID:
ivo://CDS.VizieR/J/other/FrASS/8.624907
Title:
(Sub)Stellar companions of exoplanet hosts
Short Name:
J/other/FrASS/8.
Date:
22 Feb 2022
Publisher:
CDS
Description:
We present the latest results of an ongoing multiplicity survey of exoplanet hosts, which was initiated at the Astrophysical Institute and University Observatory Jena, using data from the second data release of the ESA-Gaia mission. In this study the multiplicity of 289 targets was investigated, all located within a distance of about 500pc from the Sun. In total, 41 binary, and five hierarchical triple star systems with exoplanets were detected in the course of this project, yielding a multiplicity rate of the exoplanet hosts of about 16%. A total of 61 companions (47 stars, a white dwarf, and 13 brown dwarfs) were detected around the targets, whose equidistance and common proper motion with the exoplanet hosts were proven with their precise Gaia DR2 astrometry, which also agrees with the gravitational stability of most of these systems. The detected companions exhibit masses from about 0.016 up to 1.66M_{sun}_ and projected separations in the range between about 52 and 9555au.
14990. Substellar population of lambda Ori
ID:
ivo://CDS.VizieR/J/ApJ/610/1064
Title:
Substellar population of lambda Ori
Short Name:
J/ApJ/610/1064
Date:
21 Oct 2021
Publisher:
CDS
Description:
By collecting optical and infrared photometry and low-resolution spectroscopy, we have identified a large number of low-mass stars and brown dwarf candidates belonging to the young cluster (~5Myr) associated with the binary star {lambda} Orionis. The lowest mass object found is an M8.5 with an estimated mass of 0.02M_{Sun}_ (~0.01M_{Sun}_ for objects without spectroscopic confirmation). For those objects with spectroscopy, the measured strength of the H{alpha} emission line follows a distribution similar to other clusters with the same age range, with larger equivalent widths for cooler spectral types.

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