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0004-637X_736_2_92.pdf | 1.86 MB | Adobe PDF | 見る/開く |
タイトル: | INTRINSIC SHAPE OF STAR-FORMING BzK GALAXIES AT z ~ 2 IN GOODS-N |
著者: | Yuma, Suraphong Ohta, Kouji Yabe, Kiyoto Kajisawa, Masaru Ichikawa, Takashi |
キーワード: | galaxies: evolution galaxies: formation galaxies: high-redshift galaxies: structure |
発行日: | Jul-2011 |
出版者: | American Astronomical Society and IOP Publishing |
誌名: | The Astrophysical Journal |
巻: | 736 |
号: | 2 |
開始ページ: | 92 |
抄録: | We study the structure of star-forming galaxies at z ~ 2 in a Great Observatories Origins Deep Survey North field selected as star-forming BzK (sBzK) galaxies down to K_{AB} < 24.0 mag. Among 1029 sBzK galaxies, 551 galaxies (54%) show a single component in the Advanced Camera for Survey (ACS)/F850LP image obtained with the Hubble Space Telescope; the rest show multiple components. We fit the single-component sBzK galaxies with the single Sérsic profile using the ACS/F850LP image and find that a majority of them (64%) show a Sérsic index of n = 0.5-2.5, indicating that they have a disk-like structure. The resulting effective radii typically range from 1.0 to 3.0 kpc in the rest-frame UV wavelength. After correcting the effective radii to those in the rest-frame optical wavelength, we find that the single-component sBzK galaxies are located in the region where the local and z ~ 1 disk galaxies are distributed in the stellar-mass-size diagram, suggesting comparable surface stellar-mass density between the sBzK and z ~ 0-1 disk galaxies. All these properties suggest that the single-component sBzK galaxies are progenitors of the present-day disk galaxies. However, by studying their intrinsic shape through comparison between the observed distribution of apparent axial ratios and the distribution for triaxial models with axes A > B > C, we find that the mean B/A ratio is 0.61[+0.05]_{ –0.08} and disk thickness C/A is 0.28[+0.03]_{ –0.04}. This indicates that the single-component sBzK galaxies at z ~ 2 have a bar-like or oval shape rather than a round disk shape. The shape seems to resemble a bar/oval structure that forms through bar instability; if this is the case, the intrinsic shape may give us a clue to understand dynamical evolution of baryonic matter in a dark matter halo. |
著作権等: | © 2011. The American Astronomical Society. This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。 |
URI: | http://hdl.handle.net/2433/147140 |
DOI(出版社版): | 10.1088/0004-637X/736/2/92 |
出現コレクション: | 学術雑誌掲載論文等 |
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