2019MNRAS.488.3308L

Query : 2019MNRAS.488.3308L

2019MNRAS.488.3308L - Mon. Not. R. Astron. Soc., 488, 3308-3323 (2019/September-3)

OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing.

LI S.-S., ZANG W., UDALSKI A., SHVARTZVALD Y., HUBER D., LEE C.-U., SUMI T., GOULD A., MAO S., FOUQUE P., WANG T., DONG S., JORGENSEN U.G., COLE A., MROZ P., SZYMANSKI M.K., SKOWRON J., POLESKI R., SOSZYNSKI I., PIETRUKOWICZ P., KOZLOWSKI S., ULACZYK K., RYBICKI K.A., IWANEK P., YEE J.C., CALCHI NOVATI S., BEICHMAN C.A., BRYDEN G., CAREY S., GAUDI B.S., HENDERSON C.B., ZHU W., ALBROW M.D., CHUNG S.-J., HAN C., HWANG K.-H., JUNG Y.K., RYU Y.-H., SHIN I.-G., CHA S.-M., KIM D.-J., KIM H.-W., KIM S.-L., LEE D.-J., LEE Y., PARK B.-G., POGGE R.W., BOND I.A., ABE F., BARRY R., BENNETT D.P., BHATTACHARYA A., DONACHIE M., FUKUI A., HIRAO Y., ITOW Y., KONDO I., KOSHIMOTO N., LI M.C.A., MATSUBARA Y., MURAKI Y., MIYAZAKI S., NAGAKANE M., RANC C., RATTENBURY N.J., SUEMATSU H., SULLIVAN D.J., SUZUKI D., TRISTRAM P.J., YONEHARA A., CHRISTIE G., DRUMMOND J., GREEN J., HENNERLEY S., NATUSCH T., PORRITT I., BACHELET E., MAOZ D., STREET R.A., TSAPRAS Y., BOZZA V., DOMINIK M., HUNDERTMARK M., PEIXINHO N., SAJADIAN S., BURGDORF M.J., EVANS D.F., FIGUERA JAIMES R., FUJII Y.I., HAIKALA L.K., HELLING C., HENNING T., HINSE T.C., MANCINI L., LONGA-PENA P., RAHVAR S., RABUS M., SKOTTFELT J., SNODGRASS C., SOUTHWORTH J., UNDA-SANZANA E., VON ESSEN C., BEAULIEU J.-P., BLACKMAN J. and HILL K.

Abstract (from CDS):

We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing campaign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an asteroseismic analysis using ground-based data. We find that the source star is an oscillating red giant with average time-scale of ∼9 d. The asteroseismic analysis also provides us source properties including the source angular size (∼27 µas) and distance (∼11.5 kpc), which are essential for inferring the properties of the lens. When fitting the light curve, we test the feasibility of Gaussian processes (GPs) in handling the correlated noise caused by the variable source. We find that the parameters from the GP model are generally more loosely constrained than those from the traditional χ2 minimization method. We note that this event is the first microlensing system for which asteroseismology and GPs have been used to account for the variable source. With both finite-source effect and microlens parallax measured, we find that the lens is likely a ∼0.045 M☉ brown dwarf at distance ∼9.0 kpc, or a ∼0.073 M☉ ultracool dwarf at distance ∼9.8 kpc. Combining the estimated lens properties with a Bayesian analysis using a Galactic model, we find a ∼35 per cent probability for the lens to be a bulge object and ∼65 per cent to be a background disc object.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): asteroseismology - gravitational lensing: micro - stars: fundamental parameters - stars: oscillations

CDS comments: EWS 2016-BLG-0966 is a misprint for EWS 2015-BLG-0966.

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME UKIRT 2017-BLG-001 * 17 46 36.97848 -29 12 40.8996           ~ 5 0
2 MOA 2015-BLG-281 BD? 17 55 01.020 -29 02 49.60           ~ 22 0
3 MOA 2011-BLG-291 * 17 55 28.290 -29 10 14.38           ~ 6 0
4 OGLE BLG-LPV-153890 LP* 17 58 46.95288 -27 39 03.8376     17.714   14.125 ~ 7 0
5 NAME Galactic Bulge reg ~ ~           ~ 4794 0

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