The Milky Way stellar halo out to 40 kpc: squashed, broken but smooth

被引：251

作者：

Deason, A. J. ^{[1
]}

Belokurov, V. ^{[1
]}

Evans, N. W. ^{[1
]}

机构：

[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England

来源：

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | 2011年 / 416卷 / 04期

基金：

英国科学技术设施理事会;

关键词：

Galaxy: stellar content; Galaxy: structure; galaxies: general; galaxies: haloes; galaxies: individual: Milky Way; galaxies: photometry; DIGITAL SKY SURVEY; HORIZONTAL-BRANCH STARS; DARK-MATTER HALOS; GALACTIC HALO; DENSITY DISTRIBUTION; EMPIRICAL-MODELS; DATA RELEASE; STRIPE; 82; FIELD; SDSS;

D O I：

10.1111/j.1365-2966.2011.19237.x

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We introduce a new maximum-likelihood method to model the density profile of blue horizontal branch and blue straggler stars and apply it to the Sloan Digital Sky Survey Data Release 8 photometric catalogue. There are a large number (similar to 20 000) of these tracers available over an impressive 14 000 deg(2) in both Northern and Southern Galactic hemispheres, and they provide a robust measurement of the shape of the Milky Way stellar halo. After masking out stars in the vicinity of the Virgo overdensity and the Sagittarius stream, the data are consistent with a smooth, oblate stellar halo with a density that follows a broken power law. The best-fitting model has an inner slope alpha(in) similar to 2.3 and an outer slope alpha(out) similar to 4.6, together with a break radius occurring at similar to 27 kpc and a constant halo flattening (i.e. ratio of minor axis to major axis) of q similar to 0.6. Although a broken power law describes the density fall-off most adequately, it is also well fitted by an Einasto profile. There is no strong evidence for variations in flattening with radius, or for triaxiality of the stellar halo.

引用

页码：2903 / 2915

页数：13

共 54 条

[1] THE EIGHTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY: FIRST DATA FROM SDSS-III [J].

Aihara, Hiroaki ;

Allende Prieto, Carlos ;

An, Deokkeun ;

Anderson, Scott F. ;

Aubourg, Eric ;

Balbinot, Eduardo ;

Beers, Timothy C. ;

Berlind, Andreas A. ;

Bickerton, Steven J. ;

Bizyaev, Dmitry ;

Blanton, Michael R. ;

Bochanski, John J. ;

Bolton, Adam S. ;

Bovy, Jo ;

Brandt, W. N. ;

Brinkmann, J. ;

Brown, Peter J. ;

Brownstein, Joel R. ;

Busca, Nicolas G. ;

Campbell, Heather ;

Carr, Michael A. ;

Chen, Yanmei ;

Chiappini, Cristina ;

Comparat, Johan ;

Connolly, Natalia ;

Cortes, Marina ;

Croft, Rupert A. C. ;

Cuesta, Antonio J. ;

da Costa, Luiz N. ;

Davenport, James R. A. ;

Dawson, Kyle ;

Dhital, Saurav ;

Ealet, Anne ;

Ebelke, Garrett L. ;

Edmondson, Edward M. ;

Eisenstein, Daniel J. ;

Escoffier, Stephanie ;

Esposito, Massimiliano ;

Evans, Michael L. ;

Fan, Xiaohui ;

Femenia Castella, Bruno ;

Font-Ribera, Andreu ;

Frinchaboy, Peter M. ;

Ge, Jian ;

Gillespie, Bruce A. ;

Gilmore, G. ;

Gonzalez Hernandez, Jonay I. ;

Gott, J. Richard ;

Gould, Andrew ;

Grebel, Eva K. .

ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2011, 193 (02)

[2] GALACTIC GLOBULAR AND OPEN CLUSTERS IN THE SLOAN DIGITAL SKY SURVEY. I. CROWDED-FIELD PHOTOMETRY AND CLUSTER FIDUCIAL SEQUENCES IN ugriz [J].

An, Deokkeun ;

Johnson, Jennifer A. ;

Clem, James L. ;

Yanny, Brian ;

Rockosi, Constance M. ;

Morrison, Heather L. ;

Harding, Paul ;

Gunn, James E. ;

Prieto, Carlos Allende ;

Beers, Timothy C. ;

Cudworth, Kyle M. ;

Ivans, Inese I. ;

Ivezic, Zeljko ;

Lee, Young Sun ;

Lupton, Robert H. ;

Bizyaev, Dmitry ;

Brewington, Howard ;

Malanushenko, Elena ;

Malanushenko, Viktor ;

Oravetz, Dan ;

Pan, Kaike ;

Simmons, Audrey ;

Snedden, Stephanie ;

Watters, Shannon ;

York, Donald G. .

ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2008, 179 (02) :326-354

[3] The accretion origin of the Milky Way's stellar halo [J].

Bell, Eric F. ;

Zucker, Daniel B. ;

Belokurov, Vasily ;

Sharma, Sanjib ;

Johnston, Kathryn V. ;

Bullock, James S. ;

Hogg, David W. ;

Jahnke, Knud ;

De Jong, Jelte T. A. ;

Beers, Timothy C. ;

Evans, N. W. ;

Grebel, Eva K. ;

Ivezic, Zeljko ;

Koposov, Sergey E. ;

Rix, Hans-Walter ;

Schneider, Donald P. ;

Steinmetz, Matthias ;

Zolotov, Adi .

ASTROPHYSICAL JOURNAL, 2008, 680 (01) :295-311

[4] STELLAR POPULATION VARIATIONS IN THE MILKY WAY's STELLAR HALO [J].

Bell, Eric F. ;

Xue, Xiang Xiang ;

Rix, Hans-Walter ;

Ruhland, Christine ;

Hogg, David W. .

ASTRONOMICAL JOURNAL, 2010, 140 (06) :1850-1859

[5] The Hercules-Aquila cloud [J].

Belokurov, V. ;

Evans, N. W. ;

Bell, E. F. ;

Irwin, M. J. ;

Hewett, P. C. ;

Koposov, S. ;

Rockosi, C. M. ;

Gilmore, G. ;

Zucker, D. B. ;

Fellhauer, M. ;

Wilkinson, M. I. ;

Bramich, D. M. ;

Vidrih, S. ;

Rix, H. -W. ;

Beers, T. C. ;

Schneider, D. P. ;

Barentine, J. C. ;

Brewington, H. ;

Brinkmann, J. ;

Harvanek, M. ;

Krzesinski, J. ;

Long, D. ;

Pan, K. ;

Snedden, S. A. ;

Malanushenko, O. ;

Malanushenko, V. .

ASTROPHYSICAL JOURNAL, 2007, 657 (02) :L89-L92

[6] The field of streams: Sagittarius and its siblings [J].

Belokurov, V. ;

Zucker, D. B. ;

Evans, N. W. ;

Gilmore, G. ;

Vidrih, S. ;

Bramich, D. M. ;

Newberg, H. J. ;

Wyse, R. F. G. ;

Irwin, M. J. ;

Fellhauer, M. ;

Hewett, P. C. ;

Walton, N. A. ;

Wilkinson, M. I. ;

Cole, N. ;

Yanny, B. ;

Rockosi, C. M. ;

Beers, T. C. ;

Bell, E. F. ;

Brinkmann, J. ;

Ivezic, Z. . ;

Lupton, R. .

ASTROPHYSICAL JOURNAL, 2006, 642 (02) :L137-L140

[7] Light and motion in SDSS Stripe 82: the catalogues [J].

Bramich, D. M. ;

Vidrih, S. ;

Wyrzykowski, L. ;

Munn, J. A. ;

Lin, H. ;

Evans, N. W. ;

Smith, M. C. ;

Belokurov, V. ;

Gilmore, G. ;

Zucker, D. B. ;

Hewett, P. C. ;

Watkins, L. L. ;

Faria, D. C. ;

Fellhauer, M. ;

Miknaitis, G. ;

Bizyaev, D. ;

Ivezic, Z. ;

Schneider, D. P. ;

Snedden, S. A. ;

Malanushenko, E. ;

Malanushenko, V. ;

Pan, K. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2008, 386 (02) :887-902

[8] VELOCITY DISPERSION PROFILE OF THE MILKY WAY HALO [J].

Brown, Warren R. ;

Geller, Margaret J. ;

Kenyon, Scott J. ;

Diaferio, Antonaldo .

ASTRONOMICAL JOURNAL, 2010, 139 (01) :59-67

[9] Tracing galaxy formation with stellar halos. I. Methods [J].

Bullock, JS ;

Johnston, KV .

ASTROPHYSICAL JOURNAL, 2005, 635 (02) :931-949

[10] Adaptive spatial binning of integral-field spectroscopic data using Voronoi tessellations [J].

Cappellari, M ;

Copin, Y .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2003, 342 (02) :345-354

← 1 2 3 4 5 6 →