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arXiv 1109.4685astro-ph.CO
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Ly-alpha发射星系在z = 2.1和z = 3.1之间的演化

The Evolution of Ly-alpha Emitting Galaxies Between z = 2.1 and z = 3.1

Robin Ciardullo, Caryl Gronwall, Christopher Wolf, Emily McCathran, Nicholas A. Bond, Eric Gawiser, Lucia Guaita, John . J. Feldmeier, Ezequiel Treister, Nelson… 展开作者

Robin Ciardullo, Caryl Gronwall, Christopher Wolf, Emily McCathran, Nicholas A. Bond, Eric Gawiser, Lucia Guaita, John . J. Feldmeier, Ezequiel Treister, Nelson Padilla, Harold Francke, Ana Matkovic, Martin Altmann, David Herrera

摘要:

我们描述了一个新的,广泛的调查z=3.1 Ly-alpha发射线星系(LAEs)在扩展的钱德拉深场南(ECDF-S)的结果。通过使用来自MUSYC巡天的近顶帽5010埃滤波器和补充宽带测光,我们识别了141个物体的完整样本,这些物体的单色通量大于2.4E-17尔格/cm ^2/s,双帧等效宽度大于~ 80埃(即,Ly-alpha的静止坐标系中的20个Angstrom)。这个数据集的亮端主要由X射线源和GALEX检测的前景物体主导,但是当这些闯入者被移除时,我们仍然剩下130个LAE候选者的样本,其中39个具有光谱确认。这个样本与早期ECDF-S调查中发现的一组天体重叠,但由于我们的滤波器的红色带通,它还包括68个以前未编目的源。我们确认早期的测量z=3.1 LAE发射线光度函数,并表明,一个明显的反相关等效宽度和连续亮度可能是由于在我们的异方差数据集的相关误差的影响。最后,我们比较了z=3.1 LAEs与z=2.1 LAEs的性质。结果表明,在z~3之后的~1 Gyr,LAE光度函数发生了显著的变化,L* 衰减了~0.4 mag,L > 1.5E42 ergs/s的源的数密度下降了~ 50%,等效宽标度长度从70^{+7}_{-5}埃收缩到50^{+9}_{-6}埃。结合文献结果,我们的观测表明,在红移范围z~0到z~4,LAEs包含不到10%的宇宙的恒星形成率密度。

英文摘要:

We describe the results of a new, wide-field survey for z=3.1 Ly-alpha emission-line galaxies (LAEs) in the Extended Chandra Deep Field South (ECDF-S). By using a nearly top-hat 5010 Angstrom filter and complementary broadband photometry from the MUSYC survey, we identify a complete sample of 141 objects with monochromatic fluxes brighter than 2.4E-17 ergs/cm^2/s and observers-frame equivalent widths greater than ~ 80 Angstroms (i.e., 20 Angstroms in the rest-frame of Ly-alpha). The bright-end of this dataset is dominated by x-ray sources and foreground objects with GALEX detections, but when these interlopers are removed, we are still left with a sample of 130 LAE candidates, 39 of which have spectroscopic confirmations. This sample overlaps the set of objects found in an earlier ECDF-S survey, but due to our filter's redder bandpass, it also includes 68 previously uncataloged sources. We confirm earlier measurements of the z=3.1 LAE emission-line luminosity function, and show that an apparent anti-correlation between equivalent width and continuum brightness is likely due to the effect of correlated errors in our heteroskedastic dataset. Finally, we compare the properties of z=3.1 LAEs to LAEs found at z=2.1. We show that in the ~1 Gyr after z~3, the LAE luminosity function evolved significantly, with L* fading by ~0.4 mag, the number density of sources with L > 1.5E42 ergs/s declining by ~50%, and the equivalent width scale-length contracting from 70^{+7}_{-5} Angstroms to 50^{+9}_{-6} Angstroms. When combined with literature results, our observations demonstrate that over the redshift range z~0 to z~4, LAEs contain less than ~10% of the star-formation rate density of the universe.

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。

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