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Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482

Zub, M. and Kane, S. R. and Ofek, E. O. (2011) Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482. Astronomy and Astrophysics, 525 . Art. No. A15. ISSN 0004-6361.

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Aims. We present a detailed analysis of OGLE 2004-BLG-482, a relatively high-magnification single-lens microlensing event that exhibits clear extended-source effects. These events are relatively rare, but they potentially contain unique information on the stellar atmosphere properties of their source star, as shown in this study. Methods. Our dense photometric coverage of the overall light curve and a proper microlensing modelling allow us to derive measurements of the OGLE 2004-BLG-482source star’s linear limb-darkening coefficients in three bands, including standard Johnson-Cousins I and R, as well as in a broad clear filter. In particular, we discuss in detail the problems of multi-band and multi-site modelling on the expected precision of our results. We also obtained high-resolution UVES spectra as part of a ToO programme at ESO VLT, from which we derive the source star’s precise fundamental parameters. Results. From the high-resolution UVES spectra, we find that OGLE 2004-BLG-482’s source star is a red giant of MK type a bit later than M3, with T_(eff) = 3667 ± 150 K, log g = 2.1 ± 1.0 and an assumed solar metallicity. This is confirmed by an OGLE calibrated colour−magnitude diagram. We then obtain from a detailed microlensing modelling of the light curve linear limb-darkening coefficients that we compare to model-atmosphere predictions available in the literature, and find a very good agreement for the I and R bands. In addition, we perform a similar analysis using an alternative description of limb darkening based on a principal component analysis of ATLAS limb-darkening profiles, and also find a very good agreement between measurements and model predictions.

Item Type:Article
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URLURL TypeDescription
Kane, S. R.0000-0002-7084-0529
Ofek, E. O.0000-0002-6786-8774
Additional Information:© 2010 ESO. Received 8 March 2009, Accepted 2 September 2010, Published online 26 November 2010. Partly based on observations made at ESO (073.D-0575A). We express our gratitude to the ESO staff at Paranal for reacting at short notice to our UVES ToO request. We thank David Warren for financial support for the Mt Canopus Observatory. The OGLE project is partially supported by the Polish MNiSW grant N20303032/4275. M.Z. acknowledges a partial support of the Polish Research Grant N N203 2738 33. AC acknowledges travel support on the French CNRS/ANR grant HOLMES. D.H. was supported by Czech Science Foundation grant GACR 205/07/0824 and by the Czech Ministry of Education project MSM0021620860. This publication makes use of data products from the 2MASS and DENIS projects, as well as the SIMBAD database, Aladin and VizieR catalogue operation tools (CDS Strasbourg, France). C.H. acknowledges the support by Creative Research Initiative Program (2009-008561) of Korea Science and Engineering Foundation. B.G.P. acknowledges the support by Korea Astronomy and Space Science Institute. We thank Subo Dong for his comments on the analysis.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Ministerstwo Nauki i Szkolnictwa Wyższego (MNiSW)N20303032/4275
Ministerstwo Nauki i Szkolnictwa Wyższego (MNiSW)N N203 2738 33
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Czech Science FoundationGACR 205/07/0824
Czech Ministry of EducationMSM0021620860
Korea Science and Engineering Foundation2009-008561
Korea Astronomy and Space Science Institute (KASI)UNSPECIFIED
Agence Nationale pour la Recherche (ANR)UNSPECIFIED
Subject Keywords:gravitational lensing: micro – stars: atmospheres – techniques: high angular resolution – stars: individual: OGLE 2004-BLG-482
Record Number:CaltechAUTHORS:20110124-151916857
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Official Citation:Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482 M. Zub, A. Cassan, D. Heyrovský, P. Fouqué, H. C. Stempels, M. D. Albrow, J.-P. Beaulieu, S. Brillant, G. W. Christie, N. Kains, S. KozÅ‚owski, D. Kubas, J. Wambsganss, V. Batista, D. P. Bennett, K. Cook, C. Coutures, S. Dieters, M. Dominik, D. Dominis Prester, J. Donatowicz, J. Greenhill, K. Horne, U. G. Jørgensen, S. R. Kane, J.-B. Marquette, R. Martin, J. Menzies, K. R. Pollard, K. C. Sahu, C. Vinter, A. Williams, A. Gould, D. L. DePoy, A. Gal-Yam, B. S. Gaudi, C. Han, Y. Lipkin, D. Maoz, E. O. Ofek, B.-G. Park, R. W. Pogge, J. McCormick, A. Udalski, M. K. SzymaÅ„ski, M. Kubiak, G. PietrzyÅ„ski, I. SoszyÅ„ski, O. Szewczyk and Å. Wyrzykowski A&A 525 A15 (2011) DOI: 10.1051/0004-6361/200912007
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21871
Deposited By: Benjamin Perez
Deposited On:25 Jan 2011 00:05
Last Modified:03 Oct 2019 02:30

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