Unveiling the Galaxy Evolution by Multi-wavelength Study of Hyper Extremely Red Odjects

这项研究的目的是通过空间和地面天文台的多波长深河外巡天，发现“超极红星系”并揭示它们的性质。暗物质被认为是遥远的星系，其光谱遭受了巨大的红移。因此，它们是了解宇宙恒星形成历史的重要对象。作为研究的第一步，我们对北黄道极（NEP）进行了光学（SUBARU， CFHT），近红外（KPNPO），中远红外（空间）和无线电（WSRT）深查观测，面积分别为0.38平方度（“深”场）和5.8平方度（“宽”场）。2.4-160微米的空间观测是由2006年2月发射的AKARI红外太空望远镜进行的。第二步是从上述多波长光谱中提取出候选的HERGs。我们进行了图像分析和源提取，并生成和合并目录。由于AKARI在近红外和中红外波段的连续波长覆盖，我们可以获得AKARI独特的星系群，如“PAH（多环芳烃）发光星系”以及极红的中红外天体（ERMOs）。PAH发光星系的数量仅占中红外选定星系总数的1%，然而，它们被解释为非常年轻的恒星形成星系，因此对了解星系演化具有宝贵的意义。另一方面，ermo约占中红外选定星系总数的10%。我们发现相当一部分的ermo可能包含被尘埃遮蔽的AGN（活动星系核）。我们将进一步研究这些新种群，以揭示它们的性质，并为星系演化提供新的图像。

The purpose of this research is to discover "hyper extremely red galaxies(HERGs)" and reveal their natures through multi-wavelength deep extragalactic surveys with space and ground based observatories. The HERGs are thought to be distant galaxies with spectra suffered from large redshift. Therefore they are important objects to understand the star formation history of the universe.As a first step of this research, we performed optical(SUBARU, CFHT), near-infrared(KPNPO), mid & far-infrared(space), and radio(WSRT) deep survey observations toward the north ecliptic pole(NEP), over both 0.38 square degrees("deep" field) and 5.8 square degrees("wide" filed). The space observations at 2.4-160 microns were made with an infrared space telescope AKARI, launched in February 2006.The second step is to extract the candidates of the HERGs from the above multi-wavelengths spectia. We performed the image analysis and the source extraction, and generated and-merged catalogues. Thanks to the continuous wavelength coverage of AKARI in near and mid-infrared, we could obtain AKARI-unique galaxy populations, such as the "PAH(polycyclic aromatic hydrocarbons) luminous galaxies" as well the extremely red mid-infrared objects(ERMOs). The number of PAH luminous galaxies are only one percent of the total mid-infrared selected galaxies, however, are interpreted as very young star-forming galaxies, and thus precious to understand the galaxy evolution. The ERMOs, on the other hand, occupies approximately 10 percent of the total mid-inftared selected galaxies. We found significant portion of ERMOs may harbour the dust obscured AGN(active galactic nuclei). We will further investigate these new populations in order to reveal their natures and give new pictures on the galaxy evolution.