J/A+A/629/A1 Mapping the stellar age of the Milky Way (Surot+, 2019)
Mapping the stellar age of the Milky Way bulge with the VVV.
II. Deep JKs catalog release based on PSF photometry
Surot F., Valenti E., Hidalgo S.L., Zoccali M., Gonzalez O.A., Soekmen E.,
Minniti D., Rejkuba M., Lucas P.W.
<Astron. Astrophys. 629, A1 (2019)>
=2019A&A...629A...1S 2019A&A...629A...1S (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Galaxy catalogs
Keywords: catalogs - techniques: photometric - Galaxy: bulge -
Galaxy: stellar content
Abstract:
The bulge represents the best compromise between old and massive
Galactic component, and as such its study is a valuable opportunity to
understand how the bulk of the Milky Way formed and evolved. In
addition, being the only bulge in which we can individually resolve
stars in all evolutionary sequences, the properties of its stellar
content provide crucial insights on the formation of bulges at large.
We aim at providing a detailed and comprehensive census of the Milky
Way bulge stellar populations by producing deep and accurate
photometric catalogs of the inner ∼300 sqdeg of the Galaxy.
We perform DAOPHOT/ALLFRAME PSF-fitting photometry of multi-epochs J
and Ks images provided by the VVV survey to obtain deep photometric
catalogs. Artificial star experiments have been conducted on all
images to properly assess the completeness and the accuracy of the
photometric measurements. We present a photometric database containing
nearly 600 million stars across the bulge area surveyed by the VVV.
Through the comparison of derived color-magnitude diagrams of selected
fields representative of different levels of extinction and crowding,
we show the quality, completeness and depth of the new catalogs. With
the exception of the fields located along the plane, this new
photometry samples stars down to ∼1-2mag below the MS-TO with
unprecedented accuracy. To demonstrate the tremendous potential
inherent to this new dataset, we give few examples of possible
applications such as: i) star counts studies through the dataset
completeness map; ii) surface brightness map; and iii)
cross-correlation with Gaia DR2.
The database presented here represents an invaluable collection for
the whole community, and we encourage its exploitation. The
photometric catalogs including completeness information are publicly
available through the ESO Science Archive.
Description:
We have used a combination of J and Ks observations of the bulge
fields of the VISTA Variables in the Via Lactea (VVV) survey
(-10°<l≤10° and -10°<b<5°), collected with the wide
field near-IR imager VIRCAM mounted at the VISTA 4-m telescope at the
ESO Paranal Observatory, to derive deep JKs PSF-fitting photometry
catalogs across the whole Galactic bulge coverage. These catalogs
include J and Ks magnitude observations of about half a billion stars,
with additional information such as goodness-of-fit indicators,
completeness and color-excess values.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 42 3888 List of the VVV stacked pawprint images used in
this work, together with the corresponding
image quality, airmass and ellipticity as
derived by the fits header
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See also:
http://archive.eso.org/scienceportal/home : ESO Archive Home Page
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Filename Name of the FITS image file
20- 23 A4 --- Tile Name of the tile (VVV naming convention)
25- 26 A2 --- Band [J Ks] Passband of the image (either J or Ks)
28- 32 F5.3 --- Airmass Airmass of the observation
34- 37 F4.2 arcsec Seeing Seeing of the observation
39- 42 F4.2 --- Ell Ellipticity of the observation
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Acknowledgements:
Francisco Surot, frsurot(at)uc.cl
References:
Surot et al.:, Paper I 2019A&A...623A.168S 2019A&A...623A.168S
(End) Francisco Surot [IAC], Patricia Vannier [CDS] 23-Jul-2019