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22131. The VLT-FLAMES Survey of Massive Stars
ID:
ivo://CDS.VizieR/J/A+A/457/265
Title:
The VLT-FLAMES Survey of Massive Stars
Short Name:
J/A+A/457/265
Date:
21 Oct 2021
Publisher:
CDS
Description:
An analysis is presented of VLT-FLAMES spectroscopy for three Galactic clusters, NGC 3293, NGC 4755 and NGC 6611. Non-LTE model atmosphere calculations have been used to estimate effective temperatures (from either the helium spectrum or the silicon ionization equilibrium) and gravities (from the hydrogen spectrum). Projected rotational velocities have been deduced from the helium spectrum (for fast and moderate rotators) or the metal line spectrum (for slow rotators). The origin of the low gravity estimates for apparently near main sequence objects is discussed and is related to the stellar rotational velocity. The atmospheric parameters have been used to estimate cluster distances (which are generally in good agreement with previous determinations) and these have been used to estimate stellar luminosities and evolutionary masses. The observed Hertzsprung-Russell diagrams are compared with theoretical predictions and some discrepancies including differences in the main sequence luminosities are discussed. Cluster ages have been deduced and evidence for non-coeval star formation is found for all three of the clusters. Projected rotational velocities for targets in the older clusters, NGC 3293 and NGC 4755, have been found to be systematically larger than those for the field, confirming recent results in other similar age clusters. The distribution of projected rotational velocities are consistent with a Gaussian distribution of intrinsic rotational velocities. For the relatively unevolved targets in the older clusters, NGC 3293 and NGC 4755, the peak of the velocity distribution would be 250km/s with a full-width-half-maximum of approximately 180km/s. For NGC 6611, the sample size is relatively small but implies a lower mean rotational velocity. This may be evidence for the spin-down effect due to angular momentum loss through stellar winds, although our results are consistent with those found for very young high mass stars. For all three clusters we deduce present day mass functions with Gamma-values in the range of -1.5 to -1.8, which are similar to other young stellar clusters in the Milky Way.
22132. The VLTI/MIDI survey of Massive YSOs
ID:
ivo://CDS.VizieR/J/A+A/558/A24
Title:
The VLTI/MIDI survey of Massive YSOs
Short Name:
J/A+A/558/A24
Date:
21 Oct 2021
Publisher:
CDS
Description:
Due to inherent difficulties involved in observations and theoretical/numerical simulations of the formation of massive stars, an understanding of the early evolutionary phases of these objects remains elusive. In particular, observationally probing circumstellar material at distances <~100AU from the central star is exceedingly difficult, as such objects are rare (and thus, on average, far away) and typically deeply embedded. Long-baseline mid-infrared interferometry provides one way of obtaining the necessary spatial resolution at appropriate wavelengths to study this class of objects, however, interpreting such observations is often difficult due to sparse spatial-frequency coverage. We aim to characterize the distribution and composition of circumstellar material around young massive stars, and to investigate exactly which physical structures in these objects are probed by long-baseline mid-infrared interferometric observations. We use the two-telescope interferometric instrument MIDI of the Very Large Telescope Interferometer of the European Southern Observatory to observe a sample of 24 intermediate- and high-mass young stellar objects in the N band (8-13 micron). We had successful fringe detections for 20 objects, and present spectrally-resolved correlated fluxes and visibility levels for projected baselines of up to 128m. We fit the visibilities with geometric models to derive the sizes of the emitting regions, as well as the orientation and elongation of the circumstellar material. A subset of 14 objects show the 10 micron silicate feature in absorption in the total and correlated flux spectra. For 13 of these objects, we were able to fit the correlated flux spectra with a simple absorption model, allowing us to constrain the composition and absorptive properties of the circumstellar material.
22133. The VMC survey. XIX. Classical Cepheids in SMC
ID:
ivo://CDS.VizieR/J/ApJS/224/21
Title:
The VMC survey. XIX. Classical Cepheids in SMC
Short Name:
J/ApJS/224/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
The "VISTA near-infrared YJK_s_ survey of the Magellanic Clouds System" (VMC) is collecting deep K_s_-band time-series photometry of pulsating variable stars hosted by the two Magellanic Clouds and their connecting Bridge. In this paper, we present Y, J, K_s_ light curves for a sample of 4172 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with literature V values, allowed us to construct a variety of period-luminosity (PL), period-luminosity-color (PLC), and period-Wesenheit (PW) relationships, which are valid for Fundamental (F), First Overtone (FO), and Second Overtone (SO) pulsators. The relations involving the V, J, K_s_ bands are in agreement with their counterparts in the literature. As for the Y band, to our knowledge, we present the first CC PL, PW, and PLC relations ever derived using this filter. We also present the first near-infrared PL, PW, and PLC relations for SO pulsators to date. We used PW(V, K_s_) to estimate the relative SMC-LMC distance and, in turn, the absolute distance to the SMC. For the former quantity, we find a value of {Delta}{mu}=0.55+/-0.04mag, which is in rather good agreement with other evaluations based on CCs, but significantly larger than the results obtained from older population II distance indicators. This discrepancy might be due to the different geometric distributions of young and old tracers in both Clouds. As for the absolute distance to the SMC, our best estimates are {mu}_SMC_=19.01+/-0.05mag and {mu}_SMC_=19.04+/-0.06mag, based on two distance measurements to the LMC which rely on accurate CC and eclipsing Cepheid binary data, respectively.
22134. The VO @ ASTRON Dataset Delivery
ID:
ivo://astron.nl/~
Title:
The VO @ ASTRON Dataset Delivery
Short Name:
ASTRON VO DL
Date:
09 Jan 2020 07:54:53
Publisher:
ASTRON
Description:
This service delivers (most of) the datasets held at The VO @ ASTRON. In addition to the default (nonstandard) way of just appending accrefs to the get access URL, there is also a very simple datalink service here that, for each dataset, essentially just gives the dataset itself and possibly a preview. More advanced datalink services might be available. Some datasets may be embargoed, in which case the access yields a 403. Credentials for individual files may be obtained by contacting the site operators.
22135. The VO @ ASTRON Registry
ID:
ivo://astron.nl/__system__/services/registry
Title:
The VO @ ASTRON Registry
Short Name:
ASTRON VO Reg
Date:
09 Jan 2020 07:54:53
Publisher:
The staff at the The VO @ ASTRON
Description:
The publishing registry for the The VO @ ASTRON.
22136. The VO @ ASTRON SIAP Version 2 Service
ID:
ivo://astron.nl/__system__/siap2/sitewide
Title:
The VO @ ASTRON SIAP Version 2 Service
Short Name:
ASTRON VO SIA2
Date:
09 Jan 2020 07:54:53
Publisher:
ASTRON
Description:
The The VO @ ASTRON's sitewide SIAP version 2 service publishes all the images published through the site. For more advanced queries including uploads, all this data is also available through ObsTAP.
22137. The VO @ ASTRON TAP service
ID:
ivo://astron.nl/tap
Title:
The VO @ ASTRON TAP service
Short Name:
ASTRON VO TAP
Date:
22 Feb 2021 22:05:19
Publisher:
ASTRON
Description:
The The VO @ ASTRON's TAP end point. The Table Access Protocol (TAP) lets you execute queries against our database tables, inspect various metadata, and upload your own data. It is thus the VO's premier way to access public data holdings. Tables exposed through this endpoint include: main from the lbcs schema, main, msssvf_img_main from the mvf schema, frb_det, frb_obs from the arts_dr1 schema, img_main, main from the lofartier1 schema, mosaic, source_catalog from the lolss schema, frb_det, frb_obs from the arts_dr2 schema, main from the svc schema, img_main, main from the tgssadr schema, main, mom0 from the sauron schema, images, source_catalog from the apertif_dr_bootes schema, columns, groups, key_columns, keys, schemas, tables from the tap_schema schema, hetdex_images, main, main_merged from the hetdex schema, img_main from the msss schema, obscore from the ivoa schema, beam_cubes, calibrated_visibilities, continuum_images, flux_cal_visibilities, pol_cal_visibilities, pol_cubes, raw_visibilities, source_catalog, spectral_cubes from the apertif_dr1 schema, main_gausses, main_sources, mosaics from the lotss_dr2 schema.
22138. The VSOP (the VLBI Space Observatory Programme) 5 GHz AGN (Active Galactic Nuclei) Survey Program Analysis Data
ID:
ivo://jvo/isas/darts/halca/halca_vsop_survey_program_data
Title:
The VSOP (the VLBI Space Observatory Programme) 5 GHz AGN (Active Galactic Nuclei) Survey Program Analysis Data
Short Name:
HALCA_AGN
Date:
19 Oct 2021 06:40:34
Publisher:
JVO
Description:
A significant fraction of the mission time of VSOP was to be dedicated to the VSOP Survey Programme of bright compact Active Galactic Nuclei (AGN) at 5 GHz, which was lead by ISAS. The VSOP Survey Sources are an unbiased dataset of 294 targets, of which 82% were successfully observed.
22139. The VVV Variables (V^4^) catalog
ID:
ivo://CDS.VizieR/J/ApJ/864/11
Title:
The VVV Variables (V^4^) catalog
Short Name:
J/ApJ/864/11
Date:
21 Oct 2021
Publisher:
CDS
Description:
Time-varying phenomena are one of the most substantial sources of astrophysical information, and their study has led to many fundamental discoveries in modern astronomy. We have developed an automated tool to search for and analyze variable sources in the near-infrared Ks band using the data from the VISTA Variables in the Via Lactea (VVV) ESO Public Large Survey. This process relies on the characterization of variable sources using different variability indices calculated from time series generated with point-spread function (PSF) photometry of sources under analysis. In particular, we used two main indices, the total amplitude {Delta}Ks and the eta index {eta}, to identify variable sources. Once the variable objects are identified, periods are determined with generalized Lomb-Scargle periodograms and the information potential metric. Variability classes are assigned according to a compromise between comparisons with VVV templates and the period of the variability. The automated tool is applied on VVV tiles d001 and d002 and led to the discovery of 200 variable sources. We detected 70 irregular variable sources and 130 periodic ones. In addition, nine open-cluster candidates projected in the region are analyzed, and the infrared variable candidates found around these clusters are further scrutinized by cross-matching their locations against emission star candidates from VPHAS+ survey H{alpha} color cuts.
22140. The Washington Visual Double Star Catalog
ID:
ivo://CDS.VizieR/B/wds
Title:
The Washington Visual Double Star Catalog
Short Name:
B/wds
Date:
07 Mar 2022 08:05:57
Publisher:
CDS
Description:
The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems.

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