- ID:
- ivo://CDS.VizieR/J/AJ/130/2541
- Title:
- Core of the Shapley supercluster at 1.4GHz
- Short Name:
- J/AJ/130/2541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The core of the Shapley supercluster (A3556, A3558, SC 1327-312, SC 1329-313, and A3562) is an ideal region in which to study the effects of cluster mergers on the activity of individual galaxies. This paper presents the most comprehensive radio continuum investigation of the region, relying on a 63 pointing mosaic obtained with the Very Large Array yielding an areal coverage of nearly 7{deg}^2^.
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- ID:
- ivo://CDS.VizieR/J/ApJ/887/203
- Title:
- Core rotation period measurements of KIC stars
- Short Name:
- J/ApJ/887/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars between two and three solar masses rotate rapidly on the main sequence, and the detection of slow core and surface rotation in the core-helium burning phase for these stars places strong constraints on their angular momentum transport and loss. From a detailed asteroseismic study of the mixed-dipole mode pattern in a carefully selected, representative sample of stars, we find that slow core rotation rates in the range reported by prior studies are a general phenomenon and not a selection effect. We show that the core rotation rates of these stars decline strongly with decreasing surface gravity during the core He-burning phase. We argue that this is a model-independent indication of significant rapid angular momentum transport between the cores and envelopes of these stars. We see a significant range in core rotation rates at all surface gravities, with little evidence for a convergence toward a uniform value. We demonstrate using evolutionary models that measured surface rotation periods are a biased tracer of the true surface rotation distribution, and we argue for using stellar models for interpreting the contrast between core and surface rotation rates. The core rotation rates we measure do not have a strong mass or metallicity dependence. We argue that the emerging data strongly favor a model where angular momentum transport is much more efficient during the core He-burning phase than in the shell-burning phases that precede and follow it.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A163
- Title:
- Cores in California molecular cloud
- Short Name:
- J/A+A/620/A163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index {alpha}=-0.9+/-0.1 that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency ({epsilon}) from the prestellar core to the star of 15+/-1% and the core formation efficiency (CFE) of 5.5%, we suggest an overall star formation efficiency of about 1% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [HCO^+^]/[HNC] and [HCO^+^]/[N_2_H^+^] in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is ~50000 years.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A99
- Title:
- Cores in HII regions parameters
- Short Name:
- J/A+A/611/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formation of these pockets of ionised gas are unique to the formation of high-mass stars (M>8M_{sun}_), and present an excellent opportunity to study the final stages of accretion, which could include accretion through the HII region itself. This study of the dynamics of the gas on both sides of these ionisation boundaries in very young HII regions aims to quantify the relationship between the HII regions and their immediate environments. We present high-resolution (~0.5") ALMA observations of nine HII regions selected from the Red MSX Source (RMS, Lumsden et al., Cat. J/ApJS/208/11) survey with compact radio emission and bolometric luminosities greater than 10^4^L_{sun}_. We focus on the initial presentation of the data, including initial results from the radio recombination line H29{alpha} some complementary molecules, and the 256GHz continuum emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/1071
- Title:
- Cores in IR Dark Clouds for 300<=l<=330
- Short Name:
- J/MNRAS/422/1071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used data taken as part of the Herschel infrared Galactic Plane survey (Hi-GAL) to study 3171 infrared dark cloud (IRDC) candidates that were identified in the mid-IR (8um) by Spitzer (we refer to these as 'Spitzer-dark' regions). They all lie in the range l=300-330{deg} and |b|<=1{deg}. Of these, only 1205 were seen in emission in the far-IR (250-500um) by Herschel (we call these 'Herschel-bright' clouds). It is predicted that a dense cloud will not only be seen in absorption in the mid-IR, but will also be seen in emission in the far-IR at the longest Herschel wavebands (250-500um). If a region is dark at all wavelengths throughout the mid-IR and far-IR, then it is most likely to be simply a region of lower background IR emission (a 'hole in the sky'). Hence, it appears that previous surveys, based on Spitzer and other mid-IR data alone, may have overestimated the total IRDC population by a factor of ~2. This has implications for estimates of the star formation rate in IRDCs in the Galaxy. We studied the 1205 Herschel-bright IRDCs at 250um and found that 972 of them had at least one clearly defined 250-um peak, indicating that they contained one or more dense cores. Of these, 653 (67 per cent) contained an 8-um point source somewhere within the cloud, 149 (15 per cent) contained a 24-um point source but no 8-um source and 170 (18 per cent) contained no 24- or 8-um point sources. We use these statistics to make inferences about the lifetimes of the various evolutionary stages of IRDCs.
- ID:
- ivo://CDS.VizieR/J/A+A/324/505
- Title:
- Core velocity dispersions of globular clusters
- Short Name:
- J/A+A/324/505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present, for 25 Galactic and 10 old Magellanic globular clusters, projected velocity dispersion ({sigma}_p_) measurements obtained by applying a cross-correlation technique to integrated-light spectra. In order to understand and estimate the statistical errors of these measurements due to small numbers of bright stars dominating the integrated light, we provide an extensive discussion based on detailed numerical simulations. These errors are smaller if the integration area is larger and/or the cluster concentration higher. The simulations show that measurements are reliable when the integrated light within the integration area is brighter than a given magnitude. The statistical errors on the {sigma}_p_ measurements of Magellanic globular clusters are small because of a physically large integration area, whereas they can be important for measurements carried out over small central areas in Galactic clusters. The present observational results are used to outline a few characteristics of the globular cluster fundamental plane. In this respect, the old Magellanic globular clusters appear similar to the Galactic clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A103
- Title:
- CORNISH project. III. UCHII region catalogue
- Short Name:
- J/A+A/615/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of 239 ultra-compact HII regions (UCHIIs) found in the CORNISH survey at 5GHz and 1.5-arcsec resolution in the region 10{deg}<l<65{deg}, |b|<1{deg} is presented. This is the largest complete and well-selected sample of UCHIIs to date and provides the opportunity to explore the global and individual properties of this key state in massive star formation at multiple wavelengths. The nature of the candidates was validated, based on observational properties and calculated spectral indices, and the analysis is presented in this work. The physical sizes, luminosities and other physical properties were computed by utilising literature distances or calculating the distances whenever a value was not available. The near- and mid-infrared extended source fluxes were measured and the extinctions towards the UCHIIs were computed. The new results were combined with available data at longer wavelengths and the spectral energy distributions (SEDs) were reconstructed for 177 UCHIIs. The bolometric luminosities obtained from SED fitting are presented. By comparing the radio flux densities to previous observational epochs, we find about 5% of the sources appear to be time variable. This first high-resolution area survey of the Galactic plane shows that the total number of UCHIIs in the Galaxy is ~750 - a factor of 3-4 fewer than found in previous large area radio surveys. It will form the basis for future tests of models of massive star formation.
- ID:
- ivo://CDS.VizieR/J/ApJS/205/1
- Title:
- CORNISH project. II. Source catalog
- Short Name:
- J/ApJS/205/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CORNISH (Co-Ordinated Radio 'N' Infrared Survey for High-mass star formation) project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5GHz radio continuum part of a series of multi-wavelength surveys that focus on the northern GLIMPSE region (10{deg}<l<65{deg}), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1.5" resolution Stokes I map with a root mean square noise level better than 0.4mJy/beam. Here we describe the data-processing methods and data characteristics, and present a new, uniform catalog of compact radio emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimized to detect emission on size scales up to 14" and for unresolved sources the catalog is more than 90% complete at a flux density of 3.9mJy. We have detected 3062 sources above a 7{sigma} detection limit and present their ensemble properties. The catalog is highly reliable away from regions containing poorly sampled extended emission, which comprise less than 2% of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artifacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: HII regions, planetary nebulae, and radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/480/2423
- Title:
- CORNISH project IV. Radio-selected galactic PN
- Short Name:
- J/MNRAS/480/2423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new radio-selected sample of PNe from the CORNISH survey. We find 90 new PNe, of which 12 are newly discovered and 78 are newly classified as PN. A further 47 previously suspected PNe are confirmed as such from the analysis presented here and 24 known PNe are detected. Eight sources are classified as possible PNe or other source types.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A11
- Title:
- Corona Australis ALMA and X-Shooter data
- Short Name:
- J/A+A/626/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In recent years, the disk populations in a number of young star-forming regions have been surveyed with the Atacama Large Millimeter/submillimeter Array (ALMA). Understanding the disk properties and their correlation with the properties of the central star is critical to understanding planet formation. In particular, a decrease of the average measured disk dust mass with the age of the region has been observed, consistent with grain growth and disk dissipation. We aim to compare the general properties of disks and their host stars in the nearby (d=160pc) Corona Australis (CrA) star forming region to those of the disks and stars in other regions. We conducted high-sensitivity continuum ALMA observations of 43 Class II young stellar objects in CrA at 1.3mm (230GHz). The typical spatial resolution is 0.3''. The continuum fluxes ar e used to estimate the dust masses of the disks, and a survival analysis is performed to estimate the average dust mass. We also obtained new VLT/X-Shooter spectra for 12 of the objects in our sample for which spectral type (SpT) information was missing. Twenty-four disks were detected, and stringent limits have been put on the average dust mass of the nondetections. Taking into account the upper limits, the average disk mass in CrA is 6+/-3M_{sun}_. This value is significantly lower than that of disks in other young (1-3Myr) star forming regions (Lupus, Taurus, Chamaeleon I, and Ophiuchus) and appears to be consistent with the average disk mass of the 5-10Myr-old Upper Sco. The position of the stars in our sample on the Herzsprung-Russel diagram however seems to confirm that CrA has an age similar to Lupus. Neither external photoevaporation nor a lower-than-usual stellar mass distribution can explain the low disk masses. On the other hand, a low-mass disk population could be explained if the disks were small, which could happen if the parent cloud had a low temperature or intrinsic angular momentum, or if the angular momentum of the cloud were removed by some physical mechanism such as magnetic braking. Even in detected disks, none show clear substructures or cavities. Our results suggest that in order to fully explain and understand the dust mass distribution of protoplanetary disks and their evolution, it may also be necessary to take into consideration the initial conditions of star- and disk-formation process. These conditions at the very beginning may potentially vary from region to region, and could play a crucial role in planet formation and evolution.