在GOODS-North中寻找z>=3.5的大质量星系
Searching for massive galaxies at z>=3.5 in GOODS-North
摘要：
在GOODS-N场中，我们将大质量候选星系的空间密度和性质限制在红移z>=3.5处。通过选择斯皮策+IRAC波段中的源，组装了高度恒星质量完整的样品，包括在光学/近红外波段中非常微弱的大质量星系，这些星系将被选择在较短波长的样品所错过。z>=3.5的样品被选择为在4.5微米处低至23等，使用通过在光学、近红外和IRAC波段拟合星系SED而获得的光度红移。我们还要求检测到候选物的最亮波段是IRAC 8微米波段，以确保近红外1.6微米（静止帧）峰值落在该波段内或超出该波段。我们发现了53个z>=3.5的候选者，质量在M~10^10-10^11M_sun之间。这些星系中至少有81%被传统的基于紫外线的莱曼布雷克选择方法错过。在z>=3.5的候选星系中，有60%的星系被探测到Spitzer+MIPS辐射。虽然在某些情况下，这可能表明来自较低红移恒星形成星系或AGN的残留污染，但在最近的SCUBA，AzTEC和MAMBO调查中，这些天体中有37%也在sub-mm/mm波段被检测到，并且具有与z>=3.5的活跃星暴星系完全一致的特性。恒星质量大于等于5 × 10^10 M_sun的星系的共动数密度（对于我们的样本来说，合理的恒星质量完整性极限）是2.6 × 10 ^-5 Mpc ^-3（使用3.5<z<5范围内的体积），相应的恒星质量密度为~2.9x10^6M_sunMpc^-3，或在相同恒星质量极限以上的局域密度的~3%。对于MIPS未检测到的星系的子样本，我们发现数密度约为0.97 × 10 ^-5 Mpc ^-3，恒星质量密度约为1.15 × 10 ^6M_sun Mpc^-3。[删节]
英文摘要：
We constrain the space density and properties of massive galaxy candidates at redshifts of z>=3.5 in the GOODS-N field. By selecting sources in the Spitzer+IRAC bands, a highly stellar mass-complete sample is assembled,including massive galaxies which are very faint in the optical/near-IR bands that would be missed by samples selected at shorter wavelengths. The z>=3.5 sample was selected down to 23 mag at 4.5 micron using photometric redshifts that have been obtained by fitting the galaxies SEDs at optical, near-IR and IRAC bands. We also require that the brightest band in which candidates are detected is the IRAC 8 micron band in order to ensure that the near-IR 1.6 micron (rest-frame) peak is falling in or beyond this band. We found 53 z>=3.5 candidates, with masses in the range of M~10^10-10^11M_sun. At least ~81% of these galaxies are missed by traditional Lyman Break selection methods based on UV light. Spitzer+MIPS emission is detected for 60% of the sample of z>=3.5 galaxy candidates. Although in some cases this might suggest a residual contamination from lower redshift star-forming galaxies or AGN, 37% of these objects are also detected in the sub-mm/mm bands in recent SCUBA,AzTEC and MAMBO surveys, and have properties fully consistent with vigorous starburst galaxies at z>=3.5. The comoving number density of galaxies with stellar masses >= 5x10^10M_sun(a reasonable stellar mass completeness limit for our sample) is 2.6x10^-5Mpc^-3 (using the volume within 3.5<z<5), and the corresponding stellar mass density is ~2.9x10^6M_sunMpc^-3, or~3% of the local density above the same stellar mass limit.For the sub-sample of MIPS-undetected galaxies,we find a number density of ~0.97x10^-5Mpc^-3 and a stellar mass density of ~1.15x10^6M_sun Mpc^-3.[abridged]
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
