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- ID:
- ivo://org.gavo.dc/gaia/q3/cone
- Title:
- Gaia DR3 Lite Cone Search
- Short Name:
- DR3 lite Cone
- Date:
- 15 Aug 2024 15:17:00
- Publisher:
- The GAVO DC team
- Description:
- This schema contains data re-published from the official Gaia mirrors (such as ivo://uni-heidelberg.de/gaia/tap) either to support combining its data with local tables (the various Xlite tables) or to make the data more accessible to VO clients (e.g., epoch fluxes). Other Gaia-related data is found in, among others, the gdr3mock, gdr3spec, gedr3auto, gedr3dist, gedr3mock, and gedr3spur schemas.
- ID:
- ivo://org.gavo.dc/gedr3dist/q/cone
- Title:
- Gaia DR3 Lite Distances Subset Cone Search
- Short Name:
- DR3 lite+dist
- Date:
- 15 Aug 2024 15:17:03
- Publisher:
- The GAVO DC team
- Description:
- This service returns the most important Gaia DR3 gaia_source columns together with robust geometric and photogeometric distances for the ~1.47 billion objects in Bailer-Jones et al's distance catalogue.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/2849
- Title:
- Gaia DR1 mass-radius relation of white dwarfs
- Short Name:
- J/MNRAS/465/2849
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gaia Data Release 1 (DR1) sample of white dwarf parallaxes is presented, including six directly observed degenerates and 46 white dwarfs in wide binaries. This data set is combined with spectroscopic atmospheric parameters to study the white dwarf mass-radius relationship (MRR). Gaia parallaxes and G magnitudes are used to derive model atmosphere-dependent white dwarf radii, which can then be compared to the predictions of a theoretical MRR. We find a good agreement between Gaia DR1 parallaxes, published effective temperatures (T_eff_) and surface gravities (logg), and theoretical MRRs. As it was the case for Hipparcos, the precision of the data does not allow for the characterization of hydrogen envelope masses. The uncertainties on the spectroscopic atmospheric parameters are found to dominate the error budget and current error estimates for well-known and bright white dwarfs may be slightly optimistic. With the much larger Gaia DR2 white dwarf sample, it will be possible to explore the MRR over a much wider range of mass, T_eff_, and spectral types.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A60
- Title:
- Gaia DR2 misclassified RR Lyrae list
- Short Name:
- J/A+A/622/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gaia second Data Release (DR2) presents a first mapping of full-sky RR Lyrae stars and Cepheids observed by the spacecraft during the initial 22 months of science operations. The Specific Object Study (SOS) pipeline, developed to validate and fully characterise Cepheids and RR Lyrae stars (SOS Cep&RRL) observed by Gaia, has been presented in the documentation and papers accompanying the Gaia first Data Release. Here we describe how the SOS pipeline was modified to allow for processing the Gaia multi-band (G, GBP, and GRP) time-series photometry of all-sky candidate variables and produce specific results for confirmed RR Lyrae stars and Cepheids that are published in the DR2 catalogue. The SOS Cep&RRL processing uses tools such as the period-amplitude and the period-luminosity relations in the G band. For the analysis of the Gaia DR2 candidates we also used tools based on the GBP and GRP photometry, such as the period-Wesenheit relation in (G,GRP). Multi-band time-series photometry and characterisation by the SOS Cep&RRL pipeline are published in Gaia DR2 for 150359 such variables (9575 classified as Cepheids and 140784 as RR Lyrae stars) distributed throughout the sky. The sample includes variables in 87 globular clusters and 14 dwarf galaxies (the Magellanic Clouds, 5 classical and 7 ultra-faint dwarfs). To the best of our knowledge, as of 25 April 2018, variability of 50570 of these sources (350 Cepheids and 50,220 RR Lyrae stars) has not been reported before in the literature, therefore they are likely new discoveries by Gaia. An estimate of the interstellar absorption is published for 54272 fundamental-mode RR Lyrae stars from a relation based on the G-band amplitude and the pulsation period. Metallicities derived from the Fourier parameters of the light curves are also released for 64,932 RR Lyrae stars and 3,738 fundamental-mode classical Cepheids with period shorter than 6.3 days.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A99
- Title:
- Gaia DR2 Monoceros and ACS candidates
- Short Name:
- J/A+A/646/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gaia astrometric sample allows us to study the outermost Galactic disc, the halo, and their interface. It is precisely at the very edge of the disc where the effects of external perturbations are expected to be the most noticeable. Our goal is to detect the kinematic substructure present in the halo and at the edge of the Milky Way (MW) disc and provide observational constraints on their phase-space distribution. We download, one HP at a time, the proper motion histogram of distant stars, to which we apply a wavelet transformation to reveal the significant overdensities. We then analyse the large coherent structures that appear in the sky. We reveal a sharp yet complex anticentre dominated by Monoceros (MNC) and the Anticentre Stream (ACS) in the north - which we find have intensities comparable to the Magellanic Clouds and the Sagittarius stream - and by MNC South and TriAnd at negative latitudes. Our method allows us to perform a morpho-logical analysis of MNC and the ACS, both of which span more than 100{deg} in longitude, and to provide a high purity sample of giants with which we track MNC down to latitudes as low as ~5{deg}. Their colour-magnitude diagram is consistent with extended structures at a distance of ~10-11kpc that originated in the disc, with a very low ratio of RR-Lyrae over M giants, and with kinematics compatible with the rotation curve at those distances or slightly slower. We present a precise characterisation of MNC and the ACS, two previously known structures that our method reveals naturally, allowing us to detect them without limiting ourselves to a particular stellar type and, for the first time, using only kinematics. Our results will allow future studies to model their chemo-dynamics and evolution, thus constraining some of the most influential processes that shaped the MW.
4927. Gaia DR2 OB associations
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/663
- Title:
- Gaia DR2 OB associations
- Short Name:
- J/MNRAS/495/663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Historically, it has often been asserted that most stars form in compact clusters. In this scenario, present-day gravitationally-unbound OB associations are the result of the expansion of initially gravitationally-bound star clusters. However, this paradigm is inconsistent with recent results, both theoretical and observational, that instead favour a hierarchical picture of star formation in which stars are formed across a continuous distribution of gas densities and most OB associations never were bound clusters. Instead they are formed in-situ as the low-density side of this distribution, rather than as the remnants of expanding clusters. We utilise the second Gaia data release to quantify the degree to which OB associations are undergoing expansion and, therefore, whether OB associations are the product of expanding clusters, or whether they were born in-situ, as the large-scale, globally-unbound associations that we see today. We find that the observed kinematic properties of associations are consistent with highly substructured velocity fields and additionally require some degree of localised expansion from sub-clusters within the association. While most present-day OB associations do exhibit low levels of expansion, there is no significant correlation between radial velocity and radius. Therefore, the large-scale structure of associations is not set by the expansion of clusters, rather it is a relic of the molecular gas cloud from which the association was formed. This finding is inconsistent with a monolithic model of association formation and instead favours a hierarchical model, in which OB associations form in-situ, following the fractal structure of the gas from which they form.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A19
- Title:
- Gaia DR1 open cluster members
- Short Name:
- J/A+A/601/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. . Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier Hipparcos-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the Hipparcos data, with clearly increased luminosities for older A and F dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A93
- Title:
- Gaia DR2 open clusters in the Milky Way
- Short Name:
- J/A+A/618/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters are convenient probes of the structure and history of the Galactic disk. They are also fundamental to stellar evolution studies. The second Gaia data release contains precise astrometry at the submilliarcsecond level and homogeneous photometry at the mmag level, that can be used to characterise a large number of clusters over the entire sky. In this study we aim to establish a list of members and derive mean parameters, in particular distances, for as many clusters as possible, making use of Gaia data alone. We compiled a list of thousands of known or putative clusters from the literature. We then applied an unsupervised membership assignment code, UPMASK, to the Gaia DR2 (Cat. I/345) data contained within the fields of those clusters. We obtained a list of members and cluster parameters for 1229 clusters. As expected, the youngest clusters are seen to be tightly distributed near the Galactic plane and to trace the spiral arms of the Milky Way, while older objects are more uniformly distributed, deviate further from the plane, and tend to be located at larger Galactocentric distances. Thanks to the quality of Gaia DR2 astrometry, the fully homogeneous parameters derived in this study are the most precise to date. Furthermore, we report on the serendipitous discovery of 60 new open clusters in the fields analysed during this study.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A99
- Title:
- Gaia DR2 open clusters in the Milky Way. II
- Short Name:
- J/A+A/633/A99
- Date:
- 02 Mar 2022 11:45:02
- Publisher:
- CDS
- Description:
- Many of the open clusters listed in modern catalogues were first reported by visual astronomers as apparent over-densities of bright stars. As observational techniques and analysis methods improved, some of them have been shown to be chance alignments of stars and are not true clusters. Recent publications making use of Gaia DR2 data provided membership list for over a thousand clusters, but many nearby objects listed in the literature have so far evaded detection. We update the Gaia DR2 cluster census by performing membership determinations for known clusters that had been missed by previous studies, and for recently discovered clusters. We investigate a subset of non-detected clusters that according to their literature parameters should be easily visible in the Gaia . Confirming or disproving the existence of old, inner-disc, high-altitude clusters is especially important as their survival or disruption is linked to the dynamical processes that drive the evolution of the Milky Way. We employ the Gaia DR2 catalogue and a membership assignment procedure, as well as visual inspection of spatial, proper motion, and parallax distributions. We use membership lists provided by other authors when they are available. We derive membership lists for 150 objects, including 10 that were known prior to Gaia . We compile a final list of members for 1481 clusters. Among the objects that we are still unable to identify with Gaia data, we argue that many (mostly putative old, relatively nearby, high-altitude objects) are not true clusters. At present, the only confirmed cluster located further than 500pc away from the Galactic plane within the Solar circle is NGC 6791. It is likely that the objects discussed in this study only represent a fraction of the non-physical groupings erroneously listed in the catalogues as genuine open clusters, and that those lists need further cleaning.