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861. ALMA FITS cubes of CO(1-0) and CO(2-1)
ID:
ivo://CDS.VizieR/J/A+A/605/A116
Title:
ALMA FITS cubes of CO(1-0) and CO(2-1)
Short Name:
J/A+A/605/A116
Date:
21 Oct 2021
Publisher:
CDS
Description:
Our goal is to characterize the intermediate age, detached shell carbon star U Antliae morphologically and physically in order to study the mass-loss evolution after a possible thermal pulse. High spatial resolution ALMA observations of unprecedented quality in thermal CO lines allow us to derive first critical spatial and temporal scales and constrain modeling effects to estimate mass-loss rates for both the present day as well as the ejection period of the detached shell. The detached shell is remarkably thin, overall spherically symmetric, and shows a barely resolved filamentary substructure possibly caused by instabilities in the interaction zone of winds with different outflow velocities. The expansion age of the detached shell is of the order of 2700 years and its overall width indicates a high expansion-velocity and high mass-loss period of only a few hundred years at an average mass-loss rate of ~10^-5^M_{sun}_/yr. The post-high-mass-loss-rate-epoch evolution of U Ant shows a significant decline to a substantially lower gas expansion velocity and a mass-loss rate amounting to 4x10^-8^M_{sun}_/yr, at present being consistent with evolutionary changes as predicted for the period between thermal pulses.
862. ALMA Frontier Fields Survey. I.
ID:
ivo://CDS.VizieR/J/A+A/597/A41
Title:
ALMA Frontier Fields Survey. I.
Short Name:
J/A+A/597/A41
Date:
21 Oct 2021
Publisher:
CDS
Description:
Dusty star-forming galaxies are among the most prodigious systems at high redshift (z>1), characterized by high star-formation rates and huge dust reservoirs. The bright end of this population has been well characterized in recent years, but considerable uncertainties remain for fainter dusty star-forming galaxies, which are responsible for the bulk of star formation at high redshift and thus play a key role in galaxy growth and evolution. In this first paper of our series, we describe our methods for finding high redshift faint dusty galaxies using millimeter observations with ALMA. We obtained ALMA 1.1mm mosaic images for three strong-lensing galaxy clusters from the Frontier Fields Survey, which constitute some of the best studied gravitational lenses to date. The ~2'x2' mosaics overlap with the deep HST WFC3/IR footprints and encompass the high magnification regions of each cluster for maximum intrinsic source sensitivity. The combination of extremely high ALMA sensitivity and the magnification power of these clusters allows us to systematically probe the sub-mJy population of dusty star-forming galaxies over a large surveyed area. We present a description of the reduction and analysis of the ALMA continuum observations for the galaxy clusters Abell 2744 (z=0.308), MACS J0416.1-2403 (z=0.396) and MACS J1149.5+2223 (z=0.543), for which we reach observed rms sensitivities of 55, 59 and 71uJy/beam respectively. We detect 12 dusty star-forming galaxies at S/N>=5.0 across the three clusters, all of them presenting coincidence with near-infrared detected counterparts in the HST images. None of the sources fall close to the lensing caustics, thus they are not strongly lensed. The observed 1.1mm flux densities for the total sample of galaxies range from 0.41 to 2.82mJy, with observed effective radii spanning <~0.05" to 0.37"+/-0.21". The lensing-corrected sizes of the detected sources appear to be in the same range as those measured in brighter samples, albeit with possibly larger dispersion.
863. ALMA Frontier Fields Survey. V.
ID:
ivo://CDS.VizieR/J/A+A/633/A160
Title:
ALMA Frontier Fields Survey. V.
Short Name:
J/A+A/633/A160
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Hubble Frontier Fields offer an exceptionally deep window into the high-redshift universe, covering a substantially larger area than the Hubble Ultra-Deep field at low magnification and probing 1-2mags deeper in exceptional high-magnification regions. This unique parameter space, coupled with the exceptional multi-wavelength ancillary data, can facilitate for useful insights into distant galaxy populations. We aim to leverage Atacama Large Millimetre Array (ALMA) band 6 (~263GHz) mosaics in the central portions of five Frontier Fields to characterize the infrared (IR) properties of 1582 ultraviolet (UV)-selected Lyman-Break Galaxies (LBGs) at redshifts of z~2-8. We investigated individual and stacked fluxes and IR excess (IRX) values of the LBG sample as functions of stellar mass (M_star), redshift, UV luminosity and slope {beta}, and lensing magnification. LBG samples were derived from color-selection and photometric redshift estimation with Hubble Space Telescope photometry. Spectral energy distributions (SED)-templates were fit to obtain luminosities, stellar masses, and star formation rates for the LBG candidates. We obtained individual IR flux and IRX estimates, as well as stacked averages, using both ALMA images and u-v visibilities. Two (2) LBG candidates were individually detected above a significance of 4.1-sigma, while stacked samples of the remaining LBG candidates yielded no significant detections. We investigated our detections and upper limits in the context of the IRX-M_star and IRX-{beta} relations, probing at least one dex lower in stellar mass than past studies have done. Our upper limits exclude substantial portions of parameter space and they are sufficiently deep in a handful of cases to create mild tension with the typically assumed attenuation and consensus relations. We observe a clear and smooth trend between M* and {beta}, which extends to low masses and blue (low) {beta} values, consistent with expectations from previous works.
864. ALMA galaxy properties in the COSMOS survey field
ID:
ivo://CDS.VizieR/J/ApJ/820/83
Title:
ALMA galaxy properties in the COSMOS survey field
Short Name:
J/ApJ/820/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
ALMA Cycle 2 observations of long-wavelength dust emission in 145 star-forming galaxies are used to probe the evolution of the star-forming interstellar medium (ISM). We also develop a physical basis and empirical calibration (with 72 low-z and z~2 galaxies) for using the dust continuum as a quantitative probe of ISM masses. The galaxies with the highest star formation rates (SFRs) at <z>=2.2 and 4.4 have gas masses up to 100 times that of the Milky Way and gas mass fractions reaching 50%-80%, i.e., gas masses 1-4x their stellar masses. We find a single high-z star formation law: SFR=35 M_mol_^0.89^x(1+z)_z=2_^0.95^x(sSFR)_MS_^0.23^ M_{sun}_/yr - an approximately linear dependence on the ISM mass and an increased star formation efficiency per unit gas mass at higher redshift. Galaxies above the main sequence (MS) have larger gas masses but are converting their ISM into stars on a timescale only slightly shorter than those on the MS; thus, these "starbursts" are largely the result of having greatly increased gas masses rather than an increased efficiency of converting gas to stars. At z>1, the entire population of star-forming galaxies has ~2-5 times shorter gas depletion times than low-z galaxies. These shorter depletion times indicate a different mode of star formation in the early universe - most likely dynamically driven by compressive, high-dispersion gas motions - a natural consequence of the high gas accretion rates.
865. Almagest
ID:
ivo://CDS.VizieR/V/61
Title:
Almagest
Short Name:
V/61
Date:
22 Feb 2022
Publisher:
CDS
Description:
(no description available)
866. ALMA 106GHz continuum observations in Chamaeleon I
ID:
ivo://CDS.VizieR/J/ApJ/823/160
Title:
ALMA 106GHz continuum observations in Chamaeleon I
Short Name:
J/ApJ/823/160
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an Atacama Large Millimeter/submillimeter Array (ALMA) 106 GHz (Band 3) continuum survey of the complete population of dense cores in the Chamaeleon I molecular cloud. We detect a total of 24 continuum sources in 19 different target fields. All previously known Class 0 and Class I protostars in Chamaeleon I are detected, whereas all of the 56 starless cores in our sample are undetected. We show that the Spitzer+Herschel census of protostars in Chamaeleon I is complete, with the rate at which protostellar cores have been misclassified as starless cores calculated as <1/56, or <2%. We use synthetic observations to show that starless cores collapsing following the turbulent fragmentation scenario are detectable by our ALMA observations when their central densities exceed ~10^8^/cm^3^, with the exact density dependent on the viewing geometry. Bonnor-Ebert spheres, on the other hand, remain undetected to central densities at least as high as 10^10^/cm^3^. Our starless core non-detections are used to infer that either the star-formation rate is declining in Chamaeleon I and most of the starless cores are not collapsing, matching the findings of previous studies, or that the evolution of starless cores are more accurately described by models that develop less substructure than predicted by the turbulent fragmentation scenario, such as Bonnor-Ebert spheres. We outline future work necessary to distinguish between these two possibilities.
867. ALMA images of HD 135344B
ID:
ivo://CDS.VizieR/J/A+A/619/A161
Title:
ALMA images of HD 135344B
Short Name:
J/A+A/619/A161
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spiral arms, rings and large scale asymmetries are structures observed in high resolution observations of protoplanetary disks, and it appears that some of the disks showing spiral arms in scattered light also show asymmetries in millimeter-sized dust. HD 135344B is one of these disks. Planets are invoked as the origin of these structures, but no planet has been observed so far and up per limits are becoming more stringent with time. We want to investigate the nature of the asymmetric structure in the HD 135344B disk in order to understand the origin of the spirals and of the asymmetry seen in this disk. Ultimately, we aim at understanding whether or not one or more planets are needed to explain such structures. We present new ALMA sub-0.1" resolution observations at optically thin wavelengths (lambda=2.8mm and 1.9mm) of the HD 135344B disk. The high spatial resolution allows us to unambiguously characterize the mm-dust morphology of the disk. The low optical depth of continuum emission probes the bulk of the dust content of the vortex. Moreover, we combine the new observations with archival data at shorter wavelengths to perform a multi-wavelength analysis and to obtain information about the dust distribution and properties inside the observed asymmetry. We resolve the asymmetric disk into a symmetric ring + asymmetric crescent, and observe that: (1) the spectral index strongly decreases at the center of the vortex, consistent with the presence of large grains; (2) for the first time, an azimuthal shift of the peak of the vortex with wavelength is observed; (3) the azimuthal width of the vortex decreases at longer wavelengths, as expected for dust traps. These features allow to confirm the nature of the asymmetry as a vortex. Finally, under the assumption of optically thin emission, a lower limit to the total mass of the vortex is 0.3M_Jupiter_. Considering the uncertainties involved in this estimate, it is possible that the actual mass of the vortex is higher and possibly within the required values (~4M_Jupiter_) to launch spiral arms similar to those observed in scattered light. If this is the case, no outer planet is needed to explain the morphology.
868. ALMA images of the CND and SgrA*
ID:
ivo://CDS.VizieR/J/A+A/618/A35
Title:
ALMA images of the CND and SgrA*
Short Name:
J/A+A/618/A35
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 1"-resolution ALMA observations of the circumnuclear disk (CND) and the environment around SgrA*. The images unveil the presence of small spatial scale CO (J=3-2) molecular "cloudlets" within the central pc of the Milky Way, moving at high speeds, up to 300km/s along the line-of-sight. The CO-emitting structures show intricate morphologies: extended and filamentary at high negative-velocities (v_LSR_<-150km/s), more localized and clumpy at extreme positive-velocities (v_LSR_>+200km/s). Based on the pencil-beam CO absorption spectrum toward SgrA* synchrotron emission, we also present evidence for a diffuse gas component producing absorption features at more extreme negative-velocities (v_LSR_<-200km/s). The CND shows a clumpy spatial distribution. Its motion requires a bundle of non-uniformly rotating streams of slightly different inclinations. The inferred gas density peaks are lower than the local Roche limit. This supports that CND molecular cores are transient. We apply the two standard orbit models, spirals vs. ellipses, invoked to explain the kinematics of the ionized gas streamers around SgrA*. The location and velocities of the CO cloudlets are inconsistent with the spiral model, and only two of them are consistent with the Keplerian ellipse model. Most cloudlets, however, show similar velocities that are incompatible with the motions of the ionized streamers or with gas bounded to the central gravity. We speculate that they are leftovers of more massive, tidally disrupted, clouds that fall into the cavity, or that they originate from instabilities in the inner rim of the CND and infall from there. Molecular cloudlets, all together with a mass of several 10M_{sun}_, exist around SgrA*. Most of them must be short-lived: photoevaporated by the intense stellar radiation field, blown away by winds from massive stars, or disrupted by strong gravitational shears.
869. ALMA Long Baseline maps of G17.64+0.16
ID:
ivo://CDS.VizieR/J/A+A/627/L6
Title:
ALMA Long Baseline maps of G17.64+0.16
Short Name:
J/A+A/627/L6
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the highest angular resolution (20x15mas - 44x33au) Atacama Large Millimeter/sub-millimeter Array (ALMA) observations currently possible of the proto-O-star G17.64+0.16 in Band 6. The Cycle 5 observations with baselines out to 16 km probes scales <50au and reveal the rotating disc around G17.64+0.16, a massive forming O-type star. The disc has a ring-like enhancement in the dust emission, especially visible as arc structures to the north and south. The Keplerian kinematics are most prominently seen in the vibrationally excited water line, H_2_O (Eu=3461.9K). The mass of the central source found by modelling the Keplerian rotation is consistent with 45+/-10M_{sun}_. The H30alpha (231.9GHz) radio-recombination line and the SiO (5-4) molecular line were detected at up to the 10-sigma level. The estimated disc mass is 0.6-2.6M_{sun}_ under the optically thin assumption. Analysis of the Toomre Q parameter, in the optically thin regime, indicates that the disc stability is highly dependent on temperature. The disc currently appears stable for temperatures >150K, this does not preclude that the substructures formed earlier through disc fragmentation.
870. ALMA Magellanic Bridge A molecular clouds
ID:
ivo://CDS.VizieR/J/A+A/641/A97
Title:
ALMA Magellanic Bridge A molecular clouds
Short Name:
J/A+A/641/A97
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Magellanic Bridge is a tidal feature located between both Magellanic Clouds, containing young stars formed in situ. Its proximity allows high-resolution studies of molecular gas, dust and star formation in a tidal, low metallicity environment. Our goal is to characterize gas and dust emission in Magellanic Bridge A, the source with the highest 870um excess of emission found in single dish surveys. Using the ALMA telescope including the Morita Array, we mapped with sub-parsec resolution a 3arcmin, field of view centered on the Magellanic Bridge A molecular cloud, in 1.3mm continuum emission and ^12^CO(2-1 line emission. This region was also mapped in continuum at 870um and in ^12^CO(2-1) line emission at ~6pc resolution with the APEX telescope. To study its dust properties, we also use archival Herschel and Spitzer data. We combine the ALMA and APEX ^12^CO(2-1) line cubes to study the molecular gas emission. Magallanic Bridge A breaks up into two distinct molecular clouds in dust and ^12^CO(2-1) emission, which we call North and South. Dust emission in the North source, according to our best parameters from fitting the far-infrared fluxes, is ~3K colder than in the South source in correspondence to its less developed star formation. Both dust sources present large submillimeter excesses in LABOCA data: according to our best fits the excess over the modified blackbody (MBB) fit to the Spitzer/Herschel continuum is E(870um)~7 and E(870um)~3 for the North and South sources respectively. Nonetheless, we do not detect the corresponding 1.3mm continuum with ALMA. Our limits are compatible with the extrapolation of the MBB fits and therefore we cannot independently confirm the excess at this longer wavelength. The ^12^CO(2-1) emission is concentrated in two parsec-sized clouds with virial masses around 400 and 700M_{sun}_ each. Their bulk volume densities are n(H_2_)~0.7-2.6x10^3^cm^-3^, larger than typical bulk densities of Galactic molecular clouds. The ^12^CO luminosity to H_2_ mass conversion factor {alpha}_CO_ is 6.5 and 15.3M_{sun}_/(K.(km/s)pc^2^) for the North and South clouds, calculated using their respective virial masses and ^12^CO(2-1) luminosities. Gas mass estimates from our MBB fits to dust emission yields masses M~1.3x10^3^M_{sun}_ and 2.9x10^3^M_{sun}_ for North and South respectively, a factor of ~4 larger than the virial masses we infer from ^12^CO.

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