Gaia status, upcoming data releases, mission extension - Anthony Brown Leiden Observatory, Leiden University - KITP ...
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Gaia status, upcoming data releases,
mission extension
Anthony Brown
Leiden Observatory, Leiden University
brown@strw.leidenuniv.nl
ESA/Gaia/DPAC
Gaia
l Astrometry and spectrophotometry for > 1
billion sources
l Radial velocities for > 100 million sources
l Survey
I Complete to G = 20.7 (V = 20–22)
I Quasi-regular time-sampling over 5 years
(∼ 70 observations)
l Launch December 2013
l 5 years of nominal operations at L2
I mission extended to end 2020 (+1.5 yr)
u Second data release April 25 2018
u Photometric alerts started in 2014
u Alerts on new solar system objects started
end 2016
KITP - 2019.03.08 - 2/13
Gaia instruments and measurements
KITP - 2019.03.08 - 3/13
Mission status
l 55 months of data collected since July 25 2014
I Gaia DR2 based on 22 months
l Operations nominal, with following issues
I stray light, telescope focus evolution
I basic angle variations, contamination
I micro-meteoroids and micro-clanks
I radiation damage
I one transponder lost
KITP - 2019.03.08 - 4/13
Gaia DR2 known issues
l https://www.cosmos.esa.int/web/gaia/dr2-known-issues
l Use of DR2 astrometry: see presentation slides by Lindegren et al.
I guidelines on uncertainty inflation to get external uncertainty estimates
I better astrometric quality indicator: renormalized unit weight error (RUWE)
• quality indicators such as astrometric excess noise, gof, chi2: not recommended
I electronic tables for RUWE calculation
I spatial covariances and how to account for them
l Potentially spurious radial velocities in crowded regions
I Concerns 70 365 sources for which overlaps with spectra of neighbouring sources may lead to wrong radial
velocity
I List available as online table
I See Boubert et al., arXiv:1902.10460
l Recommendation on passbands to use for synthetic photometry
I Use the response curves from Maı́z-Appellániz & Weiler
(https://doi.org/10.1051/0004-6361/201834051)
I Recipe provided for use of these passbands with Gaia DR2 photometry
KITP - 2019.03.08 - 6/13
Gaia DR2 known issues
+10
Gaia DR2 593...064
1000
1.0 103
+8 Gaia DR2 593...352
All RVS stars with GBP − GRP Ntransits ≤ 3
N = 7213655 N = 1024881
Declination offset (arcsec)
+6
500
+4
0.8
+2
0
Radial velocity (km s−1 )
0
102
-2
−500
0.6
# of stars
-4
-6
1000
-8 Has bright neighbours Clean RVS sample
-10 0.4 N = 70365 N = 6145608
-10 -8 -6 -4 -2 0 +2 +4 +6 +8 +10 500
Right ascension offset (arcsec) 101
0
0.2
−500
0.0 100
0.0 4 6 80.2 10 12 14 0.4 16 18 4 0.6 6 8 10 0.812 14 16 1.0
18
Boubert et al., 2019, arXiv:1901.10460 GRP
KITP - 2019.03.08 - 7/13
Contents of Gaia EDR3/DR3
Schedule
u Gaia EDR3 in third quarter of 2020
u Gaia DR3 second half 2021
u Both releases based on same input data and same source list
u (E)DR3 contents on this slide and next are subject to successful processing and validation.
Source numbers are preliminary estimates!
Gaia EDR3 contents
l Astrometry
I including new quality indicators: RUWE and source image quality descriptors
l Integrated G, GBP , GRP photometry and corresponding passbands
l QSO host and galaxy morphological characterization (based on input list)
l Cross-match with external catalogues, Gaia-CRF, DR2-to-DR3 match table
KITP - 2019.03.08 - 8/13Contents of Gaia EDR3/DR3
Gaia DR3 contents
l EDR3 contents
l Classification and astrophysical parameters for TBD subset of sources
l Radial velocities; goal is to include all sources to G = 14 (∼ 40 million)
l Mean BP/RP/RVS spectra for TBD subset of sources
l Photometric variability characterization for ∼ 10 million sources
l Astrometry for ∼ 100 000 minor planets; mean reflectance spectra for ∼ 5000
l Catalogue of astrometric, spectroscopic, eclipsing binaries
KITP - 2019.03.08 - 9/13Gaia DR4
l Final release for the nominal mission
I schedule TBD
l Foreseen data products
I Full astrometric, photometric, and radial-velocity
catalogues
I All available variable-star and non-single-star
solutions
I Source classifications (probabilities) plus multiple
astrophysical parameters (derived from BP/RP, RVS,
and astrometry) for stars, unresolved binaries,
galaxies, and quasars
I Catalogue of binaries and exo-planets
I All epoch and transit data for all sources, including all
BP/RP/RVS spectra
Overall gain in precision for DR3 and DR4: factors 1.2
and 1.7 with respect to DR2
u proper motions improve by factors 1.9 and 4.5 Image credits: ESA/Gaia/DPAC, Mowlavi et al.
KITP - 2019.03.08 - 10/13Gaia extension
l Nominal Gaia mission ends mid-2019 after 5 years of measurements
l Hardware in good shape, only limiting factor is micro-propulsion fuel
I mission can continue to end-2024 (±0.5 yr)
l Proposal submitted to ESA for 5 year extension
I approved to end 2020, preliminary approval to end 2022, submit proposal for 2023–2024 in 2020
u Parallaxes, photometry, radial
velocities improve by 40% with
respect to DR4
u Proper motions improve by factor of
2.8 with respect to DR4
I Improvement of more complex
motions (e.g., planets) up to factors
of 20 Accuracy of Gaia reference frame
vs. time (F. Mignard)
u Accurate tangential motions over
22.6× larger volume
KITP - 2019.03.08 - 11/13Gaia extension
l Larger volume reached throughout
the halo at given proper motion
accuracy
l Uncover more streams
l Probe young and unmixed debris
located beyond 20–30 kpc
l Calibration of spectrophotometric
distance indicators on nearby
samples ⇒ full gain in tangential
motion performance
KITP - 2019.03.08 - 12/13Your papers are the best argument for an extended Gaia mission
Gaia
l Please acknowledge the work by DPAC and ESA in your papers!
I helps us argue the case for continued funding of the data processing
I https://gea.esac.esa.int/archive/documentation/credits.html
l Communicate your Gaia results
I https://www.cosmos.esa.int/web/gaia/communicating-your-results
KITP - 2019.03.08 - 13/13You can also read
