J/A+A/687/A94 VVV tiles b248 and b333 proper motions (Griggio+, 2024)
High-precision astrometry with VVV.
II. A near-infrared extension of Gaia into the Galactic plane.
Griggio M., Libralato M., Bellini A., Bedin L.R., Anderson J., Smith L.C.,
Minniti D.
<Astron. Astrophys. 687, A94 (2024)>
=2024A&A...687A..94G 2024A&A...687A..94G (SIMBAD/NED BibCode)
ADC_Keywords: Positional data; Photometry, infrared; Proper motions
Keywords: astrometry - parallaxes - proper motions
Abstract:
We use near-infrared, ground-based data from the VISTA Variables in
the Via Lactea (VVV) survey to indirectly extend the astrometry
provided by the Gaia catalog to objects in heavily extinct regions
toward the Galactic bulge and plane that are beyond Gaia's reach.
We made use of state-of-the-art techniques developed for
high-precision astrometry and photometry with the Hubble Space
Telescope to process the VVV data. We employed empirical, spatially
variable, effective point spread functions and local transformations
to mitigate the effects of systematic errors, like residual geometric
distortion and image motion, and to improve measurements in crowded
fields and for faint stars. We also anchored our astrometry to the
absolute reference frame of Gaia Data Release 3.
We measure between 20 and 60 times more sources than Gaia in the
region surrounding the Galactic center, obtaining a single-exposure
precision of about 12 mas and a proper-motion precision of better than
1mas/yr for bright, unsaturated sources. Our astrometry provides
an extension of Gaia into the Galactic center.We publicly release the
astro-photometric catalogs of the two VVV fields considered in this
work, which contain a total of ∼3.5 million sources. Our catalogs
cover ∼3 sq. degrees, about 0.5% of the entire VVV survey area.
Description:
Proper motions derived with the Vista Variables in the Via Lactea
survey data for tiles b248 and b333.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tileb248.dat 136 1062117 Astro-photometric catalog for VVV tile b248
tileb333.dat 137 3506274 Astro-photometric catalog for VVV tile b333
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See also:
II/376 : VISTA Variable in the Via Lactea Survey (VVV) DR4.2 (Minniti+, 2023)
Byte-by-byte Description of file: tileb248.dat
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Bytes Format Units Label Explanations
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2- 15 F14.10 deg RAdeg Right ascension (ICRS) at Ep=2012.51
18- 31 F14.10 deg DEdeg Declination (ICRS) at Ep=2012.51
35- 40 F6.3 mag Ksmag VIRCAM Ks Vega-mag magnitude
43- 49 F7.3 mag Jmag ?=999 VIRCAM Ks Vega-mag magnitude
51- 58 F8.3 mas/yr pmRA ?=999 Proper-motion along RA
60- 68 F9.3 mas/yr e_pmRA ?=999 Error on proper-motion along RA
70- 77 F8.3 mas/yr pmDE ?=999 Proper-motion along DEC
79- 86 F8.3 mas/yr e_pmDE ?=999 Error on proper-motion along DEC
94- 95 I2 --- nfitRA Number of points used to fit pmRA
101-104 F4.2 yr tfitRA Temporal baseline for pmRA fit
112-113 I2 --- nfitDE Number of points used to fit pmDEC
119-122 F4.2 yr tfitDE Temporal baseline for pmDEC fit
124-129 F6.4 --- QFIT Quality-of-fit parameter for the Ks magnitude
136 I1 --- OKFlag Flag to select reliable sources
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Byte-by-byte Description of file: tileb333.dat
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Bytes Format Units Label Explanations
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2- 15 F14.10 deg RAdeg Right ascension (ICRS) at Ep=2012.29
18- 31 F14.10 deg DEdeg Declination (ICRS) at Ep=2012.29
34- 40 F7.3 mag Ksmag VIRCAM Ks Vega-mag magnitude
43- 49 F7.3 mag Jmag ?=999 VIRCAM Ks Vega-mag magnitude
51- 58 F8.3 mas/yr pmRA ?=999 Proper-motion along RA
60- 68 F9.3 mas/yr e_pmRA ?=999 Error on proper-motion along RA
70- 77 F8.3 mas/yr pmDE ?=999 Proper-motion along DEC
79- 87 F9.3 mas/yr e_pmDE ?=999 Error on proper-motion along DEC
95- 96 I2 --- nfitRA Number of points used to fit pmRA
102-105 F4.2 yr tfitRA Temporal baseline for pmRA fit
113-114 I2 --- nfitDE Number of points used to fit pmDEC
120-123 F4.2 yr tfitDE Temporal baseline for pmDEC fit
125-130 F6.4 --- QFIT Quality-of-fit parameter for the Ks magnitude
137 I1 --- OKFlag [0/1] Flag to select reliable sources (G1)
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Global notes:
Note (G1): Flag to select reliable sources.
The flag is equal to 1 for well-measured objects and 0 otherwise.
An object is considered well-measured if all the following conditions
are verified:
- it is measured in at least 4 images;
- it is not saturated;
- nfitRA > 20
- nfitDE > 20
- abs(pmRA) < (2.5 pixels * 339 mas/pixel)/tfitRA
- abs(pmDE) < (2.5 pixels * 339 mas/pixel)/tfitDEC
- epmRA > 0
- epmDE > 0
- the proper-motion error is smaller than 5mas/yr or than 10%
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Acknowledgements:
Massimo Griggio, massimo.griggio(at)inaf.it
References:
Libralato et al., Paper I 2015MNRAS.450.1664L 2015MNRAS.450.1664L
(End) Patricia Vannier [CDS] 14-May-2024