1 - 3 of 3
Number of results to display per page
Search Results
- ID:
- ivo://org.gavo.dc/gedr3dist/q/main
- Title:
- Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3 (eDR3)
- Short Name:
- gedr3dist.main
- Date:
- 27 Dec 2024 08:31:06
- Publisher:
- The GAVO DC team
- Description:
- We estimate the distance from the Sun to sources in Gaia eDR3 that have parallaxes. We provide two types of distance estimate, together with their corresponding asymmetric uncertainties, using Bayesian posterior density functions that we sample for each source. Our prior is based on a detailed model of the 3D spatial, colour, and magnitude distribution of stars in our Galaxy that includes a 3D map of interstellar extinction. The first type of distance estimate is purely geometric, in that it only makes use of the Gaia parallax and parallax uncertainty. This uses a direction-dependent distance prior derived from our Galaxy model. The second type of distance estimate is photogeometric: in addition to parallax it also uses the source's G-band magnitude and BP-RP colour. This type of estimate uses the geometric prior together with a direction-dependent and colour-dependent prior on the absolute magnitude of the star. Our distance estimate and uncertainties are quantiles, so are invariant under logarithmic transformations. This means that our median estimate of the distance can be used to give the median estimate of the distance modulus, and likewise for the uncertainties. For applications that cannot be satisfied through TAP, you can download a `full table dump`_. .. _full table dump: /gedr3dist/q/download/form
- ID:
- ivo://org.gavo.dc/hsoy/q/q
- Title:
- The HSOY Catalog
- Short Name:
- HSOY SCS
- Date:
- 27 Dec 2024 08:31:06
- Publisher:
- The GAVO DC team
- Description:
- HSOY is a catalog of 583'001'653 objects with precise astrometry based on PPMXL and Gaia DR1. Typical formal errors at mean epoch in proper motion are below 1 mas/yr for objects brighter than 10 mag, and about 5 mas/yr at the faint end (about 20 mag). South of -30 degrees, astrometry is significantly worse. HSOY also contains, where available, USNO-B, Gaia, and 2MASS photometry. HSOY's positions and proper motions are given for epoch J2000. The catalog becomes severely incomplete faintwards of 16 mag in the G-band. The mean epochs are typically very close to Gaia's J2015. HSOY still contains about 0.7% spurious close "binaries" (non-matched stars) from the original USNO-B (marked with non-NULL clone). Also, failed matches within Gaia DR1 contribute another 1.5% spurious pairs (marked with non-NULL comp). In both cases, astrometry presumably is sub-standard. More information is available at http://dc.g-vo.org/hsoy.