Morphology and Evolution of Emission-Line Galaxies in the Hubble Ultra Deep Field
Morphology and Evolution of Emission-Line Galaxies in the Hubble Ultra Deep Field
复制标题
哈勃超深场中发射线星系的形态和演化
DOI：
10.1086/498129
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
C. Gronwall
中科院分区：
文献类型：
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作者：
N. Pirzkal;Chun Xu;I. Ferreras;S. Malhotra;B. Mobasher;J. Rhoads;A. Pasquali;N. Panagia;A. Koekemoer;H. Ferguson;C. Gronwall
我们调查的性质和演化的样本的星系选择具有突出的发射线在低分辨率的棱镜光谱的哈勃超深场（HUDF）。这些天体，eGRAPES，是晚型蓝星系，其特征是在4350猎户座框架中的小尺寸（R50 ≤ 2 kpc），低质量（5 × 109 M），以及广泛的光度和表面亮度。这些天体的质量、大小和体积密度在z = 1.5的红移范围内变化很小。另一方面，它们的表面亮度从z = 1.5到0显著降低，而它们的质光比增加了两倍。这可能是一个迹象，表明大多数低红移的eGRAPES的恒星人口比高红移的eGRAPES更老，因此大多数eGRAPES形成于更高的红移。在0.3 <z ≤ 1.5时，eGRAPES的平均体积密度为（1.8 ± 0.3）× 10 - 3 h Mpc-3。许多eGRAPES将被正式归类为明亮的紧凑型蓝色星系（LCBG），如果这些星系是基于小的物理尺寸，蓝色的固有颜色和高表面亮度而选择的，而本文讨论的样本的其余部分则形成了LCBG向更暗光度的延伸。
We investigate the properties and evolution of a sample of galaxies selected to have prominent emission lines in low-resolution grism spectra of the Hubble Ultra Deep Field (HUDF). These objects, eGRAPES, are late-type blue galaxies characterized by small proper sizes (R50 ≤ 2 kpc) in the 4350 Å rest frame, low masses (5 × 109 M☉), and a wide range of luminosities and surface brightnesses. The masses, sizes, and volume densities of these objects appear to change very little up to a redshift of z = 1.5. On the other hand, their surface brightness decreases significantly from z = 1.5 to 0, while their mass-to-light ratio increases twofold. This could be a sign that most low-redshift eGRAPES have a stellar population older than high-redshift eGRAPES and hence that most eGRAPES formed at higher redshifts. The average volume density of eGRAPES is (1.8 ± 0.3) × 10-3 h Mpc-3 at 0.3 < z ≤ 1.5. Many eGRAPES would have been formally classified as luminous compact blue galaxies (LCBGs) if these had been selected based on small physical size, blue intrinsic color, and high surface brightness, while the remainder of the sample discussed in this paper forms an extension of LCBGs toward fainter luminosities.