==========================================================================
II/369 VEXAS DR2 catalogs (Khramtsov+, 2021)
The following files can be converted to FITS (extension .fit or fit.gz)
vexasdes.dat vexasps.dat vexassm.dat
==========================================================================
Query from: http://vizier.cds.unistra.fr/viz-bin/VizieR?-source=II/369
==========================================================================
drwxr-xr-x 351 cats archive 8192 Mar 25 10:13 [Up]
drwxr-xr-x 3 cats archive 4096 Dec 19 16:45 [TAR file]
-rw-r--r-- 1 cats archive 486 Dec 19 16:44 .message
-r--r--r-- 1 cats archive 17838 Jul 16 2021 ReadMe
-rw-r--r-- 1 cats archive 1750 Dec 19 16:44 +footg5.gif
-rw-r--r-- 1 cats archive 19850 Dec 19 16:44 +footg8.gif
-r--r--r-- 1 cats archive 3175818049 Jun 17 2021 vexasdes.dat.gz [txt] [txt.gz] [fits] [fits.gz] [html]
-r--r--r-- 1 cats archive 2103745711 Jun 17 2021 vexasps.dat.gz [txt] [txt.gz] [fits] [fits.gz] [html]
-r--r--r-- 1 cats archive 2963793424 Jun 17 2021 vexassm.dat.gz [txt] [txt.gz] [fits] [fits.gz] [html]
Beginning of ReadMe :II/369 VEXAS DR2 catalogs (Khramtsov+, 2021)
================================================================================
VEXAS: VISTA EXtension to Auxiliary Surveys. Data Release 2:
Machine-learning based classification of sources in the Southern Hemisphere.
Khramtsov V., Spiniello C., Agnello A., Sergeyev A.
<Astron. Astrophys., 651, A69 (2021)>
=2021A&A...651A..69K
=2021yCat.2369....0K
================================================================================
ADC_Keywords: Surveys ; QSOs ; Galaxy catalogs ; Photometry
Keywords: astronomical databases: miscellaneous - catalogs - surveys -
methods: data analysis - virtual observatory tools
Abstract:
We present the second public data release of the VISTA EXtension to
Auxiliary Surveys (VEXAS DR2), where we classify objects into stars,
galaxies and quasars based on an ensemble of machine learning
algorithms.
The aim of VEXAS is to build the widest multi-wavelength catalogue,
providing reference magnitudes, colours and morphological information
for a large number of scientific uses.
We apply an ensemble of thirty-two different machine learning models,
based on three different algorithms and on different magnitude sets,
training samples and classification problems (two or three classes) on
the three VEXAS Data Release 1 (DR1) optical+infrared (IR) tables. The
tables were created in DR1 cross-matching VISTA near-infrared data
with Wide-field Infrared Survey Explorer far-infrared data and with
optical magnitudes from the Dark Energy Survey (VEXAS-DESW), the Sky
Mapper Survey (VEXAS-SMW), and the Panoramic Survey Telescope and
Rapid Response System Survey (VEXAS-PSW). We assemble a large table of
spectroscopically confirmed objects (VEXAS-SPEC-GOOD, 415 628 unique
objects), based on the combination of six different spectroscopic
surveys that we use for training. We develop feature imputation to
classify also objects for which magnitudes in one or more bands are
missing.
We classify in total 90106 objects in the Southern Hemisphere. Among
these, 62.9x10^6^ ( 52.6x10^6^) are classified as 'high confidence'
('secure') stars, 920000 ( 750000) as 'high confidence' ('secure')
quasars and 34.8 ( 34.1) millions as 'high confidence' ('secure')
galaxies, with pclass>=0.7 (pclass>=0.9). The DR2 tables update the
DR1 with the addition of imputed magnitudes and membership
probabilities to each of the three classes.
The density of high-confidence extragalactic objects varies strongly
with the survey depth: at pclass>0.7; there are 111/deg^2^ quasars in
the VEXAS-DESW footprint and 103/deg^2^ in the VEXAS-PSW footprint,
while only 10.7/deg^2^ in the VEXASSM footprint. Improved depth in the
midIR and coverage in the optical and nearIR are needed for the SM
footprint that is not already covered by DESW and PSW.
Description:
We present the second public data release of the VISTA EXtension to
Auxiliary Surveys (VEXAS DR2). In the VEXAS DR2, we classify objects
into stars, galaxies and QSOs using an ensemble of machine learning
models. We apply trained models on the three VEXAS optical-infrared
tables: VEXAS-DESW, VEXAS-PSW, and VEXAS-SMW. Also, we provide
imputation for missed optical-infrared magnitudes in all three tables.
As of March 2021, the VEXAS catalogue is the widest and deepest public
optical-infrared photometric dataset of the Southern Hemisphere.
The released VEXAS DR2 catalog includes three VEXAS DR1 tables:
- VISTA cross-match with Dark Energy Survey and AllWISE
(VEXAS-DESW, 35,381,482 sources)
- VISTA cross-match with Pan-STARRS and AllWISE
(VEXAS-PSW, 21,891,609 sources), and
- VISTA cross-match with SkyMapper and AllWISE
(VEXAS-SMW, 31,999,995 sources).
For each source, we provide optical-NIR-MIR photometric information
(including imputed magnitudes), classification (STAR, QSO, GALAXY).