The Milky Way tomography with Subaru Hyper Suprime-Cam. I. Halo substructures

IF 2.2 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Publications of the Astronomical Society of Japan Pub Date : 2024-01-31 DOI:10.1093/pasj/psae003

Yoshihisa Suzuki, Masashi Chiba, Yutaka Komiyama, Kohei Hayashi, Masayuki Tanaka, Tetsuya Fukushima, Scott G Carlsten, Akira Tokiwa, Tian Qiu, Masahiro Takada

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Abstract

We analyze the photometric data in the Wide layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) over ∼1200 deg2 to uncover new halo substructures beyond the distance, D⊙ ∼ 30 kpc, from the Sun. For this purpose, we develop an isochrone filter for an old, metal-poor stellar system to extract the faint main-sequence stars at a range of distances. With this method, we detect not only the previously discovered substructures such as the Orphan Stream, but also a new overdensity toward Boötes at about D⊙ ∼ 60 kpc and a new stream-like feature toward Pisces at around D⊙ ∼ 60 kpc. It has been suggested that a small-scale overdensity exists in this direction of Pisces (the so-called Pisces Overdensity), but our results show that the overdensity is widely spread with a tidally elongated feature. Combining our results with the ongoing Hyper Suprime-Cam narrow-band survey and the near-future spectroscopic survey with Prime Focus Spectrograph (PFS) will allow us to place strong constraints on the origin of these halo substructures.

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利用 Subaru Hyper Suprime-Cam 进行的银河层析成像。I. 光环子结构

我们分析了超α-Cam Subaru战略计划（HSC-SSP）中超过∼1200deg2的宽层测光数据，以发现距离太阳D⊙∼30 kpc以外的新的光环子结构。为此，我们为一个古老的、贫金属恒星系统开发了一个等时滤波器，以提取一定距离范围内的暗主序恒星。通过这种方法，我们不仅探测到了以前发现的子结构，如 "孤儿流"，而且还在大约D⊙∼60 kpc处发现了一个新的向Boötes方向的超密度，并在大约D⊙∼60 kpc处发现了一个新的向双鱼座方向的流状特征。有人认为在双鱼座的这个方向上存在一个小规模的超密度（即所谓的双鱼座超密度），但我们的结果表明，这个超密度分布很广，具有潮汐拉长的特征。将我们的研究结果与正在进行的Hyper Suprime-Cam窄波段巡天和近期使用Prime Focus Spectrograph（PFS）进行的光谱巡天结合起来，将使我们能够对这些光环子结构的起源施加强有力的约束。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Publications of the Astronomical Society of Japan 地学天文-天文与天体物理

CiteScore

4.10

自引率

13.00%

发文量

审稿时长

4-8 weeks

期刊介绍： Publications of the Astronomical Society of Japan (PASJ) publishes the results of original research in all aspects of astronomy, astrophysics, and fields closely related to them.