Journal article
The X-shaped Milky Way bulge in OGLE-III photometry and in N-body models
Monthly notices of the Royal Astronomical Society, Vol.447(2), pp.1535-1549
02/21/2015
DOI: 10.1093/mnras/stu2497
Abstract
We model the split red clump of the Galactic bulge in OGLE-III photometry, and compare the results to predictions from two N-body models. Our analysis yields precise maps of the brightness of the two red clumps, the fraction of stars in the more distant peak, and their combined surface density. We compare the observations to predictions from two N-body models previously used in the literature. Both models correctly predict several features as long as one assumes an angle alpha(Bar) approximate to 30 degrees between the Galactic bar's major axis and the line of sight to the Galactic Centre. In particular that the fraction of stars in the faint red clump should decrease with increasing longitude. The biggest discrepancies between models and data are in the rate of decline of the combined surface density of red clump stars towards negative longitudes and of the brightness difference between the two red clumps towards positive longitudes, with neither discrepancy exceeding similar to 25 per cent in amplitude. Our analysis of the red giant luminosity function also yields an estimate of the red giant branch bump parameters towards these high-latitude fields, and evidence for a high rate (similar to 25 per cent) of disc contamination in the bulge at the colour and magnitude of the red clump, with the disc contamination rate increasing towards ightlines further distant from the plane.
Details
- Title: Subtitle
- The X-shaped Milky Way bulge in OGLE-III photometry and in N-body models
- Creators
- David M. Nataf - Australian National UniversityAndrzej Udalski - University of WarsawJan Skowron - University of WarsawMichal K. Szymanski - University of WarsawMarcin Kubiak - University of WarsawGrzegorz Pietrzynski - University of WarsawIgor Soszynski - University of ConcepciónKrzysztof Ulaczyk - University of WarsawLukasz Wyrzykowski - University of WarsawRadoslaw Poleski - The Ohio State UniversityE. Athanassoula - Aix-Marseille UniversitéMelissa Ness - Max Planck SocietyJuntai Shen - Chinese Academy of SciencesZhao-Yu Li - Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.447(2), pp.1535-1549
- Publisher
- Oxford Univ Press
- DOI
- 10.1093/mnras/stu2497
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Number of pages
- 15
- Grant note
- AST-1103471 / NSF; National Science Foundation (NSF) 11073037; 11333003; 11322326 / National Natural Science Foundation of China; National Natural Science Foundation of China (NSFC) 246678 / European Research Council under the European Community; European Research Council (ERC) PITN-GA-2011-289313 / European Union; European Union (EU) 14YF1407700 / Shanghai Yangfan Talent Youth Program 2013 - x2013047098; 2014 - x2014047098 / GENCI-TGCC/CINES PGSD3-403304-2011 / NSERC; Natural Sciences and Engineering Research Council of Canada (NSERC) XDB09000000 / Strategic Priority Research Program 'The Emergence of Cosmological Structures' of Chinese Academy of Sciences FL110100012 / Australian Research Council CNES (Centre National d'Etudes Spatiales - France); Centre National D'etudes Spatiales
- Language
- English
- Date published
- 02/21/2015
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701830302771
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