Reanalysis of the <i>Gaia</i> Data Release 2 photometric sensitivity curves using HST/STIS spectrophotometry

Apellániz, J. Maíz; Weiler, Michael

doi:10.1051/0004-6361/201834051

Cited by 172 publications

(121 citation statements)

References 30 publications

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“…Apart from the parallaxes, we also make use of the threeband Gaia DR2 photometry (G, G BP , G RP ). While these are of an unprecedented precision, several recent works (Weiler 2018;Maíz Apellániz & Weiler 2018;Casagrande & VandenBerg 2018) have shown by comparison with absolute spectrophotometry that the G band suffers from a magnitude-dependent offset, and that the nominal passbands need to be slightly corrected. Therefore, in order to compare the Gaia DR2 G magnitudes to the synthetic Gaia DR2 photometry from stellar models, we have applied the G magnitude corrections, as well as the new passband definitions, given by Maíz Apellániz & Weiler (2018).…”

Section: Referencementioning

confidence: 99%

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Anders

Khalatyan

Chiappini

et al. 2019

A&A

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Combining the precise parallaxes and optical photometry delivered by Gaia's second data release (Gaia DR2) with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter than G = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5% in distance, 0.20 mag in Vband extinction, and 245 K in effective temperature for G ≤ 14, degrading towards fainter magnitudes (12%, 0.20 mag, and 245 K at G = 16; 16%, 0.23 mag, and 260 K at G = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in the Kepler, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of the Gaia mirror at the Leibniz-Institut für Astrophysik Potsdam (gaia.aip.de) and as binary tables at data.aip.de. As a first application, we provide distanceand extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic bar.

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Section: Referencementioning

confidence: 99%

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Anders

Khalatyan

Chiappini

et al. 2019

A&A

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295

312

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“…C.2 in Lindegren et al (2018), which we report here for clarity: Evans et al (2018) and Arenou et al (2018) mention that Gaia DR2 photometry is affected by some systematic errors. Evans et al (2018) andMaíz Apellániz &Weiler (2018) propose corrections to mitigate these effects. We apply these corrections and we report them here for clarity:…”

Section: Obtaining a 'Clean' Samplementioning

confidence: 99%

Structure, kinematics, and ages of the young stellar populations in the Orion region

Zari

Brown

Zeeuw

2019

A&A

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We present a study of the three dimensional structure, kinematics, and age distribution of the Orion OB association, based on the second data release of the Gaia satellite (Gaia DR2). Our goal is to obtain a complete picture of the star formation history of the Orion complex and to relate our findings to theories of sequential and triggered star formation. We select the Orion population with simple photometric criteria, and we construct a three dimensional map in galactic Cartesian coordinates to study the physical arrangement of the stellar clusters in the Orion region. The map shows structures that extend for roughly 150 pc along the line of sight, divided in multiple sub-clusters. We separate different groups by using the density based clustering algorithm DBSCAN. We study the kinematic properties of all the groups found by DBSCAN first by inspecting their proper motion distribution, and then by applying a kinematic modelling code based on an iterative maximum likelihood approach, which we use to derive their mean velocity, velocity dispersion and isotropic expansion. By using an isochrone fitting procedure we provide ages and extinction values for all the groups. We confirm the presence of an old population (∼ 15 Myr) towards the 25 Ori region, and we find that groups with ages of 12 − 15 Myr are present also towards the Belt region. We notice the presence of a population of ∼ 10 Myr also in front of the Orion A molecular cloud. Our findings suggest that star formation in Orion does not follow a simple sequential scenario, but instead consists of multiple events, which caused kinematic and physical sub-structure. To fully explain the detailed sequence of events, specific simulations and further radial velocity data are needed.

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“…The data is not only precise but also accurate, as several studies have confirmed with respect to the astrometry and photometry (e.g. Arenou et al 2018;Evans et al 2018;Lindegren et al 2018a;Luri et al 2018;Maíz Apellániz & Weiler 2018, note that this list is incomplete as Gaia DR2 calibration is an ongoing effort). Nevertheless, to achieve the highest accuracy one needs to read the "fine print" of the papers above, as there are biases and quality issues lurking in the data.…”

Section: Introductionmentioning

confidence: 85%

“…where k = 1.08 in all cases and σ s is 0.021 mas for G < 13 and 0.043 mas for G ≥ 13 in the case of parallaxes and 0.032 mas/a for G < 13 and 0.066 mas/a for G ≥ 13 in the case of proper motions. -To properly compare the observed magnitudes and colors one has to use the updated sensitivity curves of Maíz Apellániz & Weiler (2018), noting that G BP has different sensitivities for G (as obtained from the Gaia archive) larger or smaller than 10.87 mag. -The G magnitudes obtained from the archive require a correction and the resulting G should be used.…”

Section: Distances To and Membership Of Stellar Groupsmentioning

confidence: 99%

Gaia DR2 distances to Collinder 419 and NGC 2264 and new astrometric orbits for HD 193 322 Aa,Ab and 15 Mon Aa,Ab

Apellániz

2019

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Context. On the one hand, the second data release of the Gaia mission (Gaia DR2) has opened a trove of astrometric and photometric data for Galactic clusters within a few kpc of the Sun. On the other hand, lucky imaging has been an operational technique to measure the relative positions of visual binary systems for a decade and a half, a time sufficient to apply its results to the calculation of orbits of some massive multiple systems within ∼1 kpc of the Sun. Aims. As part of an ambitious research program to measure distances to Galactic stellar groups (including clusters) containing O stars, I start with two of the nearest examples: Collinder 419 in Cygnus and NGC 2264 in Monoceros. The main ionizing source for both clusters is a multiple system with an O-type primary: HD 193 322 and 15 Mon, respectively. For each of those two multiple systems I aim to derive new astrometric orbits for the Aa,Ab components. Methods. First, I present a method that uses Gaia DR2 G+G BP +G RP photometry, positions, proper motions, and parallaxes to obtain the membership and distance of a stellar group and apply it to Collinder 419 and NGC 2264. Second, I present a new code that calculates astrometric orbits by searching the whole seven-parameter orbit space and apply it to HD 193 322 Aa,Ab and 15 Mon Aa,Ab using as input literature data from the Washington Double Star Catalog (WDS) and the AstraLux measurements recently presented by Maíz Apellániz et al. (2019).Results. I obtain Gaia DR2 distances of 1006 +37 −34 pc for Collinder 419 and 719±16 pc for NGC 2264, with the main contribution to the uncertainties coming from the spatial covariance of the parallaxes. The two NGC 2264 subclusters are at the same distance (within the uncertainties) and they show a significant relative proper motion. The distances are shown to be robust. HD 193 322 Aa,Ab follows an eccentric (e = 0.58 +0.03 −0.04 ) orbit with a period of 44 ± 1 a and the three stars it contains have a total mass of 76.1 +9.9 −7.4 M . The orbit of 15 Mon Aa,Ab is even more eccentric (e = 0.770 +0.023 −0.030 ), with a period of 108 ± 12 a and a total mass of 45.1 +3.6 −3.3 M for its two stars.

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Reanalysis of the Gaia Data Release 2 photometric sensitivity curves using HST/STIS spectrophotometry

Cited by 172 publications

References 30 publications

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Structure, kinematics, and ages of the young stellar populations in the Orion region

Gaia DR2 distances to Collinder 419 and NGC 2264 and new astrometric orbits for HD 193 322 Aa,Ab and 15 Mon Aa,Ab

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