THE EXTENDED HALO OF CENTAURUS A: UNCOVERING SATELLITES, STREAMS, AND SUBSTRUCTURES
THE EXTENDED HALO OF CENTAURUS A: UNCOVERING SATELLITES, STREAMS, AND SUBSTRUCTURES
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DOI：
10.3847/0004-637x/823/1/19
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发表时间：
2015-12
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通讯作者：
D. Crnojevi'c;D. Sand;K. Spekkens;N. Caldwell;P. Guhathakurta;B. McLeod;A. Seth;J. Simon;J. Strader;E. P. S. O. Physics;Texas Tech University;Lubbock;Tx;USA.;D. Physics;Royal Military College of Canada;Kingston;Ontario;Canada;H. C. F. Astrophysics;Cambridge;Ma;UCOLick Observatory;U. California;Santa Cruz;Ca;Astronomy;U. Utah;Salt lake City;Ut;Observatories of the Carnegie Institution for Science-Observatories-of-the-Carnegie-Institution-for-102557742;Pasadena;M. University;E. Lansing.;Mi
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作者：
D. Crnojevi'c;D. Sand;K. Spekkens;N. Caldwell;P. Guhathakurta;B. McLeod;A. Seth;J. Simon;J. Strader;E. P. S. O. Physics;Texas Tech University;Lubbock;Tx;USA.;D. Physics;Royal Military College of Canada;Kingston;Ontario;Canada;H. C. F. Astrophysics;Cambridge;Ma;UCOLick Observatory;U. California;Santa Cruz;Ca;Astronomy;U. Utah;Salt lake City;Ut;Observatories of the Carnegie Institution for Science-Observatories-of-the-Carnegie-Institution-for-102557742;Pasadena;M. University;E. Lansing.;Mi
我们提出了最宽的领域解决恒星地图的日期最近的（兆秒差距）大质量椭圆星系NGC 5128（半人马座A;岑A），延伸到一个投影的银河系中心半径为150千秒差距。该数据集是我们正在进行的利用麦哲伦/Megacam成像仪进行的半人马座和雕塑家全景成像调查（PISCeS）的一部分。我们解析了一群老红巨星分支（RGB）星，其亮度低至RGB尖端以下1.5等，达到了低至2等角秒的表面亮度极限。由此产生的空间恒星密度图突出了大量以前未知的流，壳和卫星，包括围绕CenA（CenA-MM-DW 3）的第一个潮汐干扰矮星，这强调了它的活跃吸积历史。我们报告了13颗先前未知的矮卫星候选者，其中9颗被确认位于半人马座A的距离上（其余4颗未被分辨为恒星），星等范围为-13.0，中心表面亮度值为mag arcsec-2，半光半径为。这些值与本星系群矮星一致，但也位于它们分布的暗淡/弥散端;有趣的是，CenA-MM-DW 3与最近发现的室女座和后发座中的超弥散星系具有相似的性质。大多数新的矮星比以前已知的Cen A卫星更暗。根据它们的星族讨论了新发现的矮星和晕子结构，并将它们与PAndAS对M31的巡天观测结果进行了比较。
We present the widest-field resolved stellar map to date of the closest ( Mpc) massive elliptical galaxy NGC 5128 (Centaurus A; Cen A), extending out to a projected galactocentric radius of ∼150 kpc. The data set is part of our ongoing Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) utilizing the Magellan/Megacam imager. We resolve a population of old red giant branch (RGB) stars down to ∼1.5 mag below the tip of the RGB, reaching surface brightness limits as low as mag arcsec−2. The resulting spatial stellar density map highlights a plethora of previously unknown streams, shells, and satellites, including the first tidally disrupting dwarf around Cen A (CenA-MM-Dw3), which underline its active accretion history. We report 13 previously unknown dwarf satellite candidates, of which 9 are confirmed to be at the distance of Cen A (the remaining 4 are not resolved into stars), with magnitudes in the range to −13.0, central surface brightness values of mag arcsec−2, and half-light radii of . These values are in line with Local Group dwarfs but also lie at the faint/diffuse end of their distribution; interestingly, CenA-MM-Dw3 has similar properties to the recently discovered ultradiffuse galaxies in Virgo and Coma. Most of the new dwarfs are fainter than the previously known Cen A satellites. The newly discovered dwarfs and halo substructures are discussed in light of their stellar populations, and they are compared to those discovered by the PAndAS survey of M31.