2MASS All-Sky Point Source Catalog

The 2MASS project made uniformly-calibrated observations of the entire sky in the J (1.24 µm), H (1.66 µm) and Ks (2.16 µm) near-infrared bands with a pixel size of 2.0 arcsec. Sources brighter than about 1 mJy in each band were detected with a signal-to-noise ratio (SNR) greater than 10.

2MASS provides:

An unprecedented view of the Milky Way, nearly free of the obscuring effects of interstellar dust, that is revealing the true distribution of luminous mass and thus the largest structures over the extent of the Galaxy.

The first all-sky photometric census of galaxies brighter than Ks=13.5 mag, including galaxies in the 60 degree-wide "Zone of Avoidance," where dust within the Milky Way renders optical galaxy surveys incomplete. The final Catalog of >1,500,000 galaxies provides a rich statistical database, including photometric measurements in three wavelengths and a few structural parameters for large samples of galaxies in differing environments, measured at wavelengths which are sensitive to the stellar populations dominating the luminous mass.

The statistical basis to search for rare, but astrophysically important, objects, which are either cool, and thus extremely red (e.g., extremely low-luminosity stars and brown dwarfs), or heavily obscured at optical wavelengths (e.g., dust-obscured AGNs and globular clusters located in the Galactic plane).

Please include the following standard acknowledgment in any published material that makes use of 2MASS data products:

"This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation."

This dataset or service is made available by the Infrared Science Archive (IRSA) at IPAC, which is operated by the California Institute of Technology under contract with the National Aeronautics and Space Administration.

2微米全天巡天（Two Micron All Sky Survey，2MASS）项目在J（1.24 µm）、H（1.66 µm）与Ks（2.16 µm）近红外波段对全天域开展了统一校准的观测，像素尺寸为2.0角秒。在各波段中，亮度约高于1 mJy的源的信噪比（signal-to-noise ratio，SNR）均大于10。

2MASS可提供以下核心成果：
其一，近乎不受星际尘埃消光效应干扰的银河系全景观测，得以揭示发光物质的真实分布，进而勾勒出银河系全域的最大尺度结构；
其二，首个全天域亮于Ks=13.5星等的星系测光普查，覆盖了宽达60°的“回避带（Zone of Avoidance）”——该区域因银河系内的尘埃遮蔽导致光学星系巡天数据残缺不全。最终发布的包含150万余个星系的星表，提供了极为丰富的统计数据库，涵盖三个波段的测光数据与不同环境下大样本星系的若干结构参数，且观测波段对主导发光物质的恒星群体具有高灵敏度；
其三，为搜寻稀有但具有重要天体物理意义的天体提供了统计基础，这类天体要么温度极低因而呈现极强红化特征（例如极低光度恒星与褐矮星（brown dwarfs）），要么在光学波段被严重遮蔽（例如位于银道面的尘埃遮蔽活动星系核（active galactic nucleus, AGN）与球状星团）。

任何使用2MASS数据集产品的出版材料，均需包含以下标准致谢声明：
“本出版物使用了2微米全天巡天（Two Micron All Sky Survey）的数据集产品，该项目是马萨诸塞大学与红外处理与分析中心/加州理工学院的合作项目，由美国国家航空航天局（National Aeronautics and Space Administration，NASA）与美国国家科学基金会（National Science Foundation，NSF）资助。”

本数据集或服务由加州理工学院下属的红外科学档案馆（Infrared Science Archive, IRSA）提供，该机构受美国国家航空航天局合同委托运营。

搜集汇总

背景与挑战

背景概述

2MASS全天点源目录是一个近红外天文数据集，基于1997-2001年的观测，于2003年发布，覆盖全天J、H、Ks波段，提供统一校准数据，检测亮度约高于1 mJy的天体。其关键特点包括：揭示银河系质量分布，避免星际尘埃影响；首次全天星系普查，包含超过150万个星系的测光和结构参数；支持搜索罕见天体如褐矮星和尘埃遮蔽活动星系核，为天文研究提供重要统计基础。