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1311. Barium stars abundances and kinematics
ID:
ivo://CDS.VizieR/J/MNRAS/459/4299
Title:
Barium stars abundances and kinematics
Short Name:
J/MNRAS/459/4299
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scaleheight, radial velocities, abundances of the Na, Al, {alpha}-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars cannot be represented by a single Gaussian distribution. The abundances of {alpha}-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anticorrelated with the metallicity. Our kinematical analysis showed that 90 per cent of the barium stars belong to the thin disc population. Based on their luminosities, none of the barium stars are luminous enough to be an asymptotic giant branch star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.
1312. Barlenses in the CALIFA survey
ID:
ivo://CDS.VizieR/J/A+A/618/A34
Title:
Barlenses in the CALIFA survey
Short Name:
J/A+A/618/A34
Date:
21 Oct 2021
Publisher:
CDS
Description:
It is theoretically predicted that, at low galaxy inclinations, boxy/peanut bar components have a barlens appearance of a round central component embedded in the narrow bar. We investigate barlenses in the Calar Alto Legacy Integral Field Area (CALIFA) survey galaxies, studying their morphologies, stellar populations, and metallicities. We show that, when present, barlenses account for a significant portion of light of photometric bulges, i.e., the excess light on top of the disks, which highlights the importance of bars in accumulating central galaxy mass concentrations in the cosmic timescale. We made multi-component decompositions for a sample of 46 barlens galaxies drawn from the CALIFA survey, where M_{star}_/M_{sun}_=10^9.7^-10^11.4^ and z=0.005-0.03. Unsharp masks of the Sloan Digital Sky Survey (SDSS) r'-band mosaics were used to identify the boxy/peanut or X-shaped features. Barlenses are identified in the images using our simulation snapshots as an additional guide. Our decompositions with GALFIT include bulges, disks, and bars as well as barlenses as a separate component. For 26 of the decomposed galaxies the CALIFA DR2 V500 grating data cubes were used to explore stellar ages and metallicities at the regions of various structure components. We find that 25+/-2% of the 1064 galaxies in the whole CALIFA sample show either X-shaped or barlens features. In the decomposed galaxies with barlenses, on average 13%+/-2% of the total galaxy light belongs to this component, leaving less than 10% for possible separate bulge components. Most importantly, bars and barlenses are found to have similar cumulative stellar age and metallicity distributions. The metallicities in barlenses are on average near solar, but exhibit a large range. In some of the galaxies barlenses and X-shaped features appear simultaneously, in which case the bar origin of the barlens is unambiguous. This is the first time that a combined morphological and stellar population analysis is used to study barlenses. We show that their stars are accumulated in a prolonged time period concurrently with the evolution of the narrow bar.
1313. Barn 335 ALMA datacubes
ID:
ivo://CDS.VizieR/J/A+A/631/A64
Title:
Barn 335 ALMA datacubes
Short Name:
J/A+A/631/A64
Date:
21 Oct 2021
Publisher:
CDS
Description:
The relationship between outflow launching and the formation of accretion disks around young stellar objects is still not entirely understood, which is why spectrally and spatially resolved observations are needed. Recently, the Atacama Large Millimetre/ sub-millimetre Array (ALMA) carried out long-baseline observations towards a handful of young sources, revealing connections between outflows and the inner regions of disks. Here we aim to determine the small-scale kinematical and morphological properties of the outflow from the isolated protostar B335 for which no Keplerian disk has, so far, been observed on scales down to 10au. We used ALMA in its longest-baseline configuration to observe emission from CO isotopologues, SiO, SO_2_, and CH_3_OH. The proximity of B335 provides a resolution of ~3au (0.03"). We also combined our long-baseline data with archival observations to produce a high-fidelity image covering scales up to 700 au (7"). ^12^CO has an X-shaped morphology with arms ~50au in width that we associate with the walls of an outflow cavity, similar to what is observed on larger scales. Long-baseline continuum emission is confined to <7au from the protostar, while short- baseline continuum emission follows the ^12^CO outflow and cavity walls. Methanol is detected within ~30au of the protostar. SiO is also detected in the vicinity of the protostar, but extended along the outflow. The ^12^CO outflow does not show any clear signs of rotation at distances >=30au from the protostar. SiO traces the protostellar jet on small scales, but without obvious rotation. CH_3_OH and SO_2_ trace a region <16au in diameter, centred on the continuum peak, which is clearly rotating. Using episodic, high-velocity, ^12^CO features, we estimate the launching radius of the outflow to be<0.1au and dynamical timescales of the order of a few years.
1314. Barnard 1b CO, NH_2_D and SO images
ID:
ivo://CDS.VizieR/J/A+A/606/L3
Title:
Barnard 1b CO, NH_2_D and SO images
Short Name:
J/A+A/606/L3
Date:
21 Oct 2021
Publisher:
CDS
Description:
The extremely young Class 0 object B1b-S and the first hydrostatic core (FSHC) candidate, B1b-N, provide a unique opportunity to study the chemical changes produced in the elusive transition from the prestellar core to the protostellar phase. We present 40"x70" images of Barnard 1b in the ^13^CO 1-0, C^18^O 1-0, NH_2_D 1(1,1)a-1(0,1)s, and SO 3(2)-2(1) lines obtained with the NOEMA interferometer. The observed chemical segregation allows us to unveil the physical structure of this young protostellar system down to scales of ~500au. The two protostellar objects are embedded in an elongated condensation, with a velocity gradient of ~0.2-0.4m/s/au in the east-west direction, reminiscent of an axial collapse. The NH_2_D data reveal cold and dense pseudo-disks (R~500-1000au) around each protostar. Moreover, we observe evidence of pseudo-disk rotation around B1b-S. We do not see any signature of the bipolar outflows associated with B1b-N and B1b-S, which were previously detected in H_2_CO and CH_3_OH, in any of the imaged species.The non-detection of SO constrains the SO/CH_3_OH abundance ratio in the high-velocity gas.
1315. Barnard 1b-N and 1b-S 350GHz images
ID:
ivo://CDS.VizieR/J/A+A/606/A35
Title:
Barnard 1b-N and 1b-S 350GHz images
Short Name:
J/A+A/606/A35
Date:
21 Oct 2021
Publisher:
CDS
Description:
The formation epoch of protostellar disks is debated because of the competing roles of rotation, turbulence, and magnetic fields in the early stages of low-mass star formation. Magnetohydrodynamics simulations of collapsing cores predict that rotationally supported disks may form in strongly magnetized cores through ambipolar diffusion or misalignment between the rotation axis and the magnetic field orientation. Detailed studies of individual sources are needed to cross check the theoretical predictions. We present 0.06-0.1arcsec resolution images at 350GHz toward B1b-N and B1b-S, which are young class 0 protostars, possibly first hydrostatic cores. The images have been obtained with ALMA, and we compare these data with magnetohydrodynamics simulations of a collapsing turbulent and magnetized core. The submillimeter continuum emission is spatially resolved by ALMA. Compact structures with optically thick 350GHz emission are detected toward both B1b-N and B1b-S, with 0.2 and 0.35arcsec radii (46 and 80au at the Perseus distance of 230pc), within a more extended envelope. The flux ratio between the compact structure and the envelope is lower in B1b-N than in B1b-S, in agreement with its earlier evolutionary status. The size and orientation of the compact structure are consistent with 0.2arcsec resolution 32GHz observations obtained with the Very Large Array as a part of the VANDAM survey, suggesting that grains have grown through coagulation. The morphology, temperature, and densities of the compact structures are consistent with those of disks formed in numerical simulations of collapsing cores. Moreover, the properties of B1b-N are consistent with those of a very young protostar, possibly a first hydrostatic core. These observations provide support for the early formation of disks around low-mass protostars.
1316. Barnard 1b-N and 1b-S nascent bipolar outflows
ID:
ivo://CDS.VizieR/J/A+A/577/L2
Title:
Barnard 1b-N and 1b-S nascent bipolar outflows
Short Name:
J/A+A/577/L2
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the theory of star formation, the first hydrostatic core (FHSC) phase is a critical step in which a condensed object emerges from a prestellar core. This step lasts about one thousand years, a very short time compared with the lifetime of prestellar cores, and therefore is hard to detect unambiguously. We present IRAM Plateau de Bure observations of the Barnard 1b dense molecular core, combining detections of H2CO and CH3OH spectral lines and dust continuum at 2.3" resolution (~500AU). The two compact cores B1b-N and B1b-S are detected in the dust continuum at 2mm, with fluxes that agree with their spectral energy distribution. Molecular outflows associated with both cores are detected. They are inclined relative to the direction of the magnetic field, in agreement with predictions of collapse in turbulent and magnetized gas with a ratio of mass to magnetic flux somewhat higher than the critical value, {mu}~2-7. The outflow associated with B1b-S presents sharp spatial structures, with ejection velocities of up to ~7km/s from the mean velocity. Its dynamical age is estimated to be ~2000yr. The B1b-N outflow is smaller and slower, with a short dynamical age of ~1000yr. The B1b-N outflow mass, mass-loss rate, and mechanical luminosity agree well with theoretical predictions of FHSC. These observations confirm the early evolutionary stage of B1b-N and the slightly more evolved stage of B1b-S.
1317. Barnard 30 dark cloud IR and submm data
ID:
ivo://CDS.VizieR/J/A+A/612/A79
Title:
Barnard 30 dark cloud IR and submm data
Short Name:
J/A+A/612/A79
Date:
21 Oct 2021
Publisher:
CDS
Description:
The early evolutionary stage of brown dwarfs (BDs) is not very well characterized, especially during the embedded phase. Our goal is to gain insight into the dominant formation mechanism of very low-mass objects and BDs. We have conducted deep observations at 870um obtained with the LABOCA bolometer at the APEX telescope in order to identify young submillimeter (submm) sources in the Barnard 30 dark cloud. We have complemented these data with multi-wavelength observations from the optical to the far-IR and compiled complete spectral energy distributions in order to identify the counterparts, characterize the sources and to assess their membership to the association and stellar or substellar status based on the available photometric information. We have identified 34 submm sources and a substantial number of possible and probable Barnard 30 members within each individual APEX/LABOCA beam. They can be classified into three distinct groups. First, 15 of these 34 have a clear optical or IR counterpart to the submm peak and nine of them are potential proto-BD candidates. Moreover, a substantial number of them could be multiple systems. A second group of 13 sources comprises candidate members with significant infrared excesses located away from the central submm emission. All of them include BD candidates, some displaying IR excess, but their association with submm emission is unclear. In addition, we have found six starless cores and, based on the total dust mass estimate, three might be pre-substellar (or pre-BDs) cores. Finally, the complete characterization of our APEX/LABOCA sources, focusing on those detected at 24 and/or 70um, indicates that in our sample of 34 submm sources there are, at least: two WTTs, four CTTs, five young stellar objects, eight proto-BD candidates (with another three dubious cases), and one very low luminosity objects.
1318. Barnard's Catalogue of 349 Dark Objects in the Sky
ID:
ivo://CDS.VizieR/VII/220A
Title:
Barnard's Catalogue of 349 Dark Objects in the Sky
Short Name:
VII/220A
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalogue was created based on the original published catalogue by Barnard E.E., 1927, Carnegie Institution of Washington, "A photographic Atlas of selected regions of the Milky Way". The catalogue contains positions of 349 Barnard Objects. The objects with numbers from 1 to 175 are classified in the first Barnard catalogue (1919ApJ....49....1B); three of the objects in that list have been omitted here (Nos 52, 131a, and 172) because these objects had been listed twice. The objects from Barnard's second list are numbered from 201 to 370 -- there are therefore no objects having the numbers from 176 to 200. Their positions were determined by Miss Calvert. The epoch for all positions in the original published catalogue was 1875.0. Positions for both 1875.0 and 2000.0, the diameters and the notes are included in this machine-readable catalogue.
1319. Barred galaxies structural decomposition
ID:
ivo://CDS.VizieR/J/MNRAS/473/4731
Title:
Barred galaxies structural decomposition
Short Name:
J/MNRAS/473/4731
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of two-component (disc+bar) and three-component (disc+bar+bulge) multiwavelength 2D photometric decompositions of barred galaxies in five Sloan Digital Sky Survey (SDSS) bands (ugriz). This sample of ~3500 nearby (z<0.06) galaxies with strong bars selected from the Galaxy Zoo citizen science project is the largest sample of barred galaxies to be studied using photometric decompositions that include a bar component. With detailed structural analysis, we obtain physical quantities such as the bar- and bulge-to-total luminosity ratios, effective radii, Sersic indices and colours of the individual components. We observe a clear difference in the colours of the components, the discs being bluer than the bars and bulges. An overwhelming fraction of bulge components have Sersic indices consistent with being pseudo-bulges. By comparing the barred galaxies with a mass-matched and volume-limited sample of unbarred galaxies, we examine the connection between the presence of a large-scale galactic bar and the properties of discs and bulges. We find that the discs of unbarred galaxies are significantly bluer compared to the discs of barred galaxies, while there is no significant difference in the colours of the bulges. We find possible evidence of secular evolution via bars that leads to the build-up of pseudo-bulges and to the quenching of star formation in the discs. We identify a subsample of unbarred galaxies with an inner lens/oval and find that their properties are similar to barred galaxies, consistent with an evolutionary scenario in which bars dissolve into lenses. This scenario deserves further investigation through both theoretical and observational work.
1320. Barred S0 galaxies in the Coma cluster
ID:
ivo://CDS.VizieR/J/MNRAS/439/1749
Title:
Barred S0 galaxies in the Coma cluster
Short Name:
J/MNRAS/439/1749
Date:
21 Oct 2021
Publisher:
CDS
Description:
This study uses r-band images from the Eighth Data Release of the Sloan Digital Sky Survey (SDSS DR8) to study bars in lenticular (S0) galaxies in one of the nearest rich cluster environments, the Coma cluster. We develop techniques for bar detection and assess their success when applied to SDSS image data. To detect and characterize bars, we perform 2D bulge+disc+bar light decompositions of galaxy images with galfit. Using a sample of artificial galaxy images, we determine the faintest magnitude at which bars can be successfully measured at the depth and resolution of SDSS. We perform detailed decompositions of 83 S0 galaxies in Coma, 64 from a central sample, and 19 from a cluster outskirt sample. For the central sample, the S0 bar fraction is 72^+5^_-6_%. This value is significantly higher than that obtained using an ellipse-fitting method for bar detection, 48^+6^_-6_%. At a fixed luminosity, barred S0s are redder in g-r colour than unbarred S0s by 0.02mag. The frequency and strength of bars increase towards fainter luminosities. Neither central metallicity nor stellar age distributions differ significantly between barred and unbarred S0s. There is an increase in the bar fraction towards the cluster core, but this is at a low significance level. Bars have at most a weak correlation with cluster-centric radius.

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