Infrared Survey of the Galactic Center with the 1.4-m IRSF telescope at SAAO

使用 SAAO 的 1.4 米 IRSF 望远镜对银河系中心进行红外巡天

• 批准号: 15340061
• 负责人: NAGATA Tetsuya
• 金额: $ 9.98万
• 依托单位: Kyoto University (2004-2005)Nagoya University (2003)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340061/
• 关键词: optical infrared telescope; infrared survey; Galactic center; Galaxy; interstellar dust; interstellar extinction; red clump stars; Galactic structure

Infrared survey of the Galactic center has been performed in the J, H, and K bands with the high resolution of 0.45"/pix. The observed area covers ±1 deg (±150 pc) in the Galactic latitude and ±10 deg (±1.5 kpc) in the Galactic longitude. We used Simultaneous Infrared Imager for Unbiased Survey (SIRIUS) with three 1024x1024 HgCdTe arrays, which were attached to the IRSF 1.4-m telescope placed at South African Astronomical Observatory by Nagoya University. The array read-out has been improved and the efficiency of the observation is now extremely high.First, using the detected red clump stars in the central degree, which are in the core He burning phase, we determined the interstellar reddening law ; this is different from the color-excess method in the literature, and much more accurate. The interstellar extinction is deviated from the Rieke-Lebofsky law (proportional to the -1.6th order of the wavelength), and rather follows to the -2nd order of the wavelength. It has been sometimes argued that the infrared extinction is "universal" in the various lines of sight, but this result has presented clear evidence against it. The determined index itself is also important in dereddening the observed spectra.Then, we derived the peak of distribution of red clump stars in the ±1.5 kpc region around the Galactic center. The apparent magnitude peak changes continuously along the Galactic plane, from K=13.4 mag to 12.2 mag after dereddening. This variation is explained by the bar-like structure found in previous studies, but we find an additional inner structure within the region of 1.2 kpc in diameter, where the apparent magnitude peak changes by only 0.1 mag.

银心红外巡天工作在J、H、K波段进行，高分辨率为0.45英寸/像素。观测区域覆盖银纬度±1度（±150 pc）和银纬度±10度（± 1.5 kpc）在银河经度我们使用同步红外成像仪进行无偏测量（SIRIUS）与三个1024x1024。 HgCdTe阵列，安装在名古屋大学南非天文台的IRSF 1.4米望远镜上，阵列读数得到了改进，观测效率极高。首先，利用探测到的红丛星。在中心度，即核心He燃烧阶段，我们确定了星际红化规律；这与文献中的颜色过剩法不同，并且更加准确。偏离了 Rieke-Lebofsky 定律（与波长的 -1.6 级成比例），而是遵循波长的 -2 级。有时有人认为红外消光在各种谱线中是“普遍的”。目视，但这个结果提供了明确的证据反对它，所确定的指数本身对于观测光谱的去红化也很重要。然后，我们得出了±1.5范围内红团簇星的分布峰值。银河系中心周围的 kpc 区域的视星等峰值沿银河平面不断变化，在去红化后从 K=13.4 星等变化到 12.2 星等，这种变化可以通过之前研究中发现的条状结构来解释，但我们发现了一个额外的内部结构。直径为 1.2 kpc 区域内的结构，其中视星等峰值仅变化 0.1 mag。

项目成果

Nagashima, C.: "An Optical and Near Infrared Search for Brown Dwarfs in the Pleiades Cluster"Mon.Not.R.Astron.Soc. 343. 1263-1270 (2003)

Nagashima, C.：“对昴宿星团中褐矮星的光学和近红外搜索”Mon.Not.R.Astron.Soc。

A Distinct Structure inside the Galactic Bar

• DOI: 10.1086/429291
• 发表时间: 2005-02
• 期刊: The Astrophysical Journal Letters
• 作者: S. Nishiyama;T. Nagata;D. Baba;Y. Haba;R. Kadowaki;D. Kato;M. Kurita;C. Nagashima;T. Nagayama;Yuka Murai;Y. Nakajima;M. Tamura;H. Nakaya;K. Sugitani;T. Naoi;N. Matsunaga;T. Tanabé;N. Kusakabe;S. Sato

A deep near-infrared survey around the giant radio galaxy PKS 1343-601

围绕巨大射电星系 PKS 1343-601 的深度近红外巡天

• 发表时间: 2004
• 期刊: Mon.Notes Roy.Astron.Soc. 354
• 作者: Nagayama;T
• 通讯作者: T

Interstellar Extinction Law in the J, H, and Ks Bands toward the Galactic Center

• DOI: 10.1086/499038
• 发表时间: 2006-01
• 期刊: The Astrophysical Journal
• 作者: S. Nishiyama;T. Nagata;N. Kusakabe;N. Matsunaga;T. Naoi;D. Kato;C. Nagashima;K. Sugitani;M. Tamura

A Near-Infrared Study of the NGC 7538 Star-forming Region

• DOI: 10.1086/425068
• 发表时间: 2004-08
• 期刊: The Astrophysical Journal
• 作者: D. Ojha;M. Tamura;Y. Nakajima;M. Fukagawa;K. Sugitani;C. Nagashima;T. Nagayama;T. Nagata;S. Sato;S. Vig;S. Ghosh;A. Pickles;M. Momose;K. Ogura