Verification of Photometric Parallaxes with Gaia DR2 Data

Malkov, O. Yu.; Карпов, С.; Kovaleva, D. A.; Sichevsky, S. G.; Chulkov, Dmitry; Dluzhnevskaya, O. B.; Kniazev, A. Y.; Mickaelian, A. M.; Миронов, А. В.; Murthy, Jayant; Sytov, A. Yu.; Zhao, Gang; Жуков, А. О.

doi:10.3390/galaxies7010007

Cited by 6 publications

(4 citation statements)

References 39 publications

(47 reference statements)

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“…The comparison exhibits a good agreement (see Malkov et al (2018b) for details). A comparison of our results with recently released Gaia DR2 data also demonstrates a good agreement for stars as faint as 19 m .6 g SDSS , and shows that our method allows us to determine spectral type, distance and interstellar extinction of objects out to 4.5 kpc Malkov et al (2018a). It indicates that the proposed algorithm (after some modifications, required for low galactic latitudes) can be used for construction of a 3D map of interstellar extinction in the Milky Way Galaxy.…”

Section: Determination Of Interstellar Extinctionsupporting

confidence: 68%

Stellar and interstellar parameters from large photometric surveys

Malkov

Karpov

Kovaleva

et al. 2020

ComBAO

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The parameterization of stars is a well-known problem and used for various purposes in astronomy. We have shown that multicolor photometric data from large modern surveys can be used for parameterization of stars. With sufficiently good quality photometry, one may compute a 3D extinction map by comparing catalogued multicolor photometry with photometry derived from the secondary estimators such as the distance modulus and the interstellar extinction law with suitable calibration tables for absolute magnitudes with reasonable spectral types, extinctions and distances.

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Section: Determination Of Interstellar Extinctionsupporting

confidence: 68%

Stellar and interstellar parameters from large photometric surveys

Malkov

Karpov

Kovaleva

et al. 2020

ComBAO

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show abstract

“…For the latter, we used the conservative value of 5 (roughly two thirds of PSF, in contrast to 3 used e.g. in Bianchi & Shiao (2020)) for GALEX, 2 for WISE, 0.1 for Gaia DR2, and 1 for all groundbased surveys, the same way as in Malkov et al (2018) and Malkov et al (2020). For an initial analysis presented here, we did not perform any comparison of object brightness in various catalogues, thus potentially excluding brighter UV objects where much fainter optical objects are present inside the matching circle.…”

Section: Cross-matching Of Multi-wavelength Surveysmentioning

confidence: 99%

“…This combined photometry can be used for relatively accurate determination of the parameters of galaxies, stars, and the interstellar medium. In particular, it was shown (Malkov et al 2018) that multicolour photometric data from large modern surveys can be used for parameterization of stars closer than around 4.5 kpc and brighter than 𝑔 SDSS = 19. 𝑚 6, including estimation of parallax and interstellar extinction value.…”

Section: Introductionmentioning

confidence: 99%

Search for Ultraviolet Luminous Objects in GALEX data

Karpov,

Malkov,

Zhao

2021

Preprint

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Selection of extreme objects in the data from large-scale sky surveys is a powerful tool for the detection of new classes of astrophysical objects or rare stages of their evolution. The crossmatching of catalogues and analysis of the color indices of their objects is a usual approach for this problem which has already provided a lot of interesting results. However, the analysis of objects that are found in only one of the surveys, and absent in all others, should also attract close attention, as it may lead to the discovery of both transients and objects with extreme color values. Here we report on the initial study aimed at the detection of objects with a significant UV excess in their spectra by cross-matching of the GALEX all-sky catalogue with several other surveys in different wavelength ranges and analyzing the ones visible in GALEX only, or having extreme UV to optical colors (ultraviolet luminous objects). We describe the methodology for such investigation, explain the selection of surveys for this study, and show the initial results based on the search in a small fraction of the sky. We uncovered several prominent UV-only objects lacking the counterparts in the catalogues of longer wavelengths, and discuss their possible nature. We also detected a single source showing an extreme UV to optical color and corresponding to UV flare on a cool sdM subdwarf star. Finally, we discuss the possible populations of objects that may be revealed in a future larger-scale analysis of this kind.

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“…Here A i = f (A V ) is the extinction in the i-th photometric band, and can be determined from the interstel-lar extinction law. The procedure and pilot results (including their comparison with recent Gaia Data Release 2 (DR2) parallaxes) are described in detail in Malkov et al (2010), Sichevskiy et al (2013), Sichevskij et al (2014), Malkov et al (2018a) and Malkov et al (2018b).…”

Section: Introductionmentioning

confidence: 99%

Statistical relations between stellar spectral and luminosity classes and stellar effective temperature and surface gravity

Malkov

Kovaleva

Sichevsky

et al. 2020

Res. Astron. Astrophys.

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We have determined new statistical relations to estimate the fundamental atmospheric parameters of effective temperature and surface gravity, using MK spectral classification, and vice versa. The relations were constructed based on the published calibration tables (for main sequence stars) and observational data from stellar spectral atlases (for giants and supergiants). These new relations were applied to field giants with known atmospheric parameters, and the results of the comparison of our estimations with available spectral classification have been quite satisfactory.

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Verification of Photometric Parallaxes with Gaia DR2 Data

Cited by 6 publications

References 39 publications

Stellar and interstellar parameters from large photometric surveys

Stellar and interstellar parameters from large photometric surveys

Search for Ultraviolet Luminous Objects in GALEX data

Statistical relations between stellar spectral and luminosity classes and stellar effective temperature and surface gravity

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