Structure of the Milky Way stellar halo out to its outer boundary with blue horizontal-branch stars
文献类型：期刊论文
| 作者 | Fukushima, Tetsuya1; Chiba, Masashi1; Homma, Daisuke1,4; Okamoto, Sakurako4,5; Komiyama, Yutaka2,4; Tanaka, Masayuki4; Tanaka, Mikito1; Arimoto, Nobuo3; Matsuno, Tadafumi2,4 |
| 刊名 | PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
 |
| 出版日期 | 2018-08-01 |
| 卷号 | 70期号:4页码:13 |
| ISSN号 | 0004-6264 |
| 关键词 | Galaxy: halo Galaxy: structure stars: horizontal-branch |
| DOI | 10.1093/pasj/psy060 |
| 英文摘要 | We present the structure of the Milky Way stellar halo beyond Galactocentric distances of r = 50 kpc traced by blue horizontal-branch (BHB) stars, which are extracted from the survey data in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). We select BHB candidates based on (g, r, i, z) photometry, where the z-band is on the Paschen series and the colors that involve the z-band are sensitive to surface gravity. About 450 BHB candidates are identified between r = 50 kpc and 300 kpc, most of which are beyond the reach of previous large surveys, including the Sloan Digital Sky Survey. We find that the global structure of the stellar halo in this range has substructures, which are especially remarkable in the GAMA15H and XMM-LSS fields in the HSC-SSP. We find that the stellar halo can be fitted to a single power-law density profile with an index of alpha similar or equal to 3.3 (3.5) with (without) these fields and its global axial ratio is q similar or equal to 2.2 (1.3). Thus, the stellar halo may be significantly disturbed and be made in a prolate form by halo substructures, perhaps associated with the Sagittarius stream in its extension beyond r similar to 100 kpc. For a broken power-law model allowing different power-law indices inside/outside a break radius, we obtain a steep power-law slope of alpha similar or equal to 5 outside a break radius of similar to 100 kpc (200 kpc) for the case with (without) GAMA15H and XMM-LSS. This radius of 200 kpc might be as close as a halo boundary if there is any, although a larger BHB sample is required from further HSC-SSP surveys to increase its statistical significance. |
| 资助项目 | JSPS[25287062] ; MEXT[15H05889] ; MEXT[16H01086] ; MEXT[17H01101] ; MEXT[18H04334] ; Brain Pool Program - Ministry of Science and ICT through the National Research Foundation of Korea[2018H1D3A2000902] ; FIRST program from the Japanese Cabinet Office ; Ministry of Education, Culture, Sports, Science and Technology (MEXT) ; Japan Society for the Promotion of Science (JSPS) ; Japan Science and Technology Agency (JST) ; Toray Science Foundation ; NAOJ ; Kavli IPMU ; KEK ; ASIAA ; Princeton University ; National Aeronautics and Space Administration through the Planetary Science Division of the NASA Science Mission Directorate[NNX08AR22G] ; National Science Foundation[AST-1238877] |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| 出版者 | OXFORD UNIV PRESS |
| WOS记录号 | WOS:000456069400013 |
| 源URL | [http://119.78.226.72/handle/331011/31987]  |
| 专题 | 中国科学院上海天文台 |
| 通讯作者 | Fukushima, Tetsuya |
| 作者单位 | 1.Tohoku Univ, Astron Inst, Aoba Ku, Sendai, Miyagi 9808578, Japan 2.Grad Univ Adv Studies, Osawa 2-21-1, Mitaka, Tokyo 1818588, Japan 3.Seoul Natl Univ, Dept Phys & Astron, Astron Program, 599 Gwanak Ro, Seoul 151742, South Korea 4.Natl Astron Observ Japan, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan 5.Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China |
| 推荐引用方式 GB/T 7714 | Fukushima, Tetsuya,Chiba, Masashi,Homma, Daisuke,et al. Structure of the Milky Way stellar halo out to its outer boundary with blue horizontal-branch stars[J]. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN,2018,70(4):13. |
| APA | Fukushima, Tetsuya.,Chiba, Masashi.,Homma, Daisuke.,Okamoto, Sakurako.,Komiyama, Yutaka.,...&Matsuno, Tadafumi.(2018).Structure of the Milky Way stellar halo out to its outer boundary with blue horizontal-branch stars.PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN,70(4),13. |
| MLA | Fukushima, Tetsuya,et al."Structure of the Milky Way stellar halo out to its outer boundary with blue horizontal-branch stars".PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70.4(2018):13. |
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来源：上海天文台
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