Sagittarius Tidal Debris 90 Kiloparsecs from the Galactic Center
Sagittarius Tidal Debris 90 Kiloparsecs from the Galactic Center
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DOI：
10.1086/379316
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发表时间：
2003-09
期刊：
影响因子：
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通讯作者：
H. Newberg;B. Yanny;E. Grebel;G. Hennessy;Ž. Ivezić;D. Martinez-Delgado;M. Odenkirchen;H. Rix
中科院分区：
文献类型：
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作者：
H. Newberg;B. Yanny;E. Grebel;G. Hennessy;Ž. Ivezić;D. Martinez-Delgado;M. Odenkirchen;H. Rix
本文给出了一个新的过密度的A色星群，这些恒星位于银河系恒星晕的遥远部分，而斯隆数字巡天的星等为G0=20.3。相关变星RR型天琴座候选星的识别支持了这些是蓝色水平分支恒星的说法。假设这些恒星的绝对星等M=0.7，太阳离银河系中心8.5kpc，推断出这些恒星离银河系中心的距离为90kpc。新的潮汐碎片与其他已证实的人马座矮星系分裂产生的潮汐碎片在同一平面内不到10kpc，可能与后面的潮汐臂有关。从M星推算到射手座的距离大约比我们推测的距离小13%。潮汐碎片的宽度至少为10°，并在天空中被追踪20°以上。球状星团NGC2419位于探测到的潮汐碎片中，也可能曾经与人马座矮星系有关。
A new overdensity of A-colored stars in distant parts of the Milky Way's stellar halo, at a dereddened Sloan Digital Sky Survey magnitude of g0 = 20.3, is presented. Identification of associated variable RR Lyrae candidates supports the claim that these are blue horizontal branch stars. The inferred distance of these stars from the Galactic center is 90 kpc, assuming that the absolute magnitude of these stars is M = 0.7 and that the Sun is 8.5 kpc from the Galactic center. The new tidal debris is within 10 kpc of the same plane as other confirmed tidal debris from the disruption of the Sagittarius dwarf galaxy and could be associated with the trailing tidal arm. Distances to the Sagittarius stream estimated from M stars are about 13% smaller than our inferred distances. The tidal debris has a width of at least 10° and is traced for more than 20° across the sky. The globular cluster NGC 2419 is located within the detected tidal debris and may also have once been associated with the Sagittarius dwarf galaxy.