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arXiv 0910.1091astro-ph.COastro-ph.GA
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BLAST:遥远星系中的远红外/射电相关

BLAST: the far-infrared/radio correlation in distant galaxies

R. J. Ivison, David M. Alexander, Andy D. Biggs, W. N. Brandt, Edward L. Chapin, Kristen E. K. Coppin, Mark J. Devlin, Mark Dickinson, James Dunlop, Simon Dye, … 展开作者

R. J. Ivison, David M. Alexander, Andy D. Biggs, W. N. Brandt, Edward L. Chapin, Kristen E. K. Coppin, Mark J. Devlin, Mark Dickinson, James Dunlop, Simon Dye, Stephen A. Eales, David T. Frayer, Mark Halpern, David H. Hughes, Edo Ibar, A. Kovacs, Gaelen Marsden, L. Moncelsi, Calvin B. Netterfield, Enzo Pascale, Guillaume Patanchon, D. A. Rafferty, Marie Rex, Eva Schinnerer, Douglas Scott, C. Semisch, Ian Smail, A. M. Swinbank, Matthew D. P. Truch, Gregory S. Tucker, Marco P. Viero, Fabian Walter, Axel Weiss, Donald V. Wiebe, Y. Q. Xue

摘要:

我们调查远红外(FIR)和无线电光度在遥远的星系,现代天文学的关键之间的相关性。我们使用的数据来自卫星携带的大孔径亚毫米望远镜(BLAST),斯皮策,大顶点BOlometer CamerA(LABOCA),甚大阵列(VLA)和巨型米波射电望远镜(GMRT)在扩展的钱德拉深场南(ECDFS)。对于BLAST 250微米选定星系的目录,我们重新测量了70- 870微米的通量密度,它们最有可能的24微米对应物的位置,其中值[四分位数]红移为0.74 [0.25,1.57]。由此,我们确定了单色光通量密度比q_250 = log_10(S_250micron / S_1400MHz)和辐射热当量q_IR。在z ~= 0.6时,我们的250微米滤波器探测静止坐标系160微米辐射,我们发现局部星系相对于q_160没有演化。我们还堆叠的FIR和submm图像的位置,24微米和无线电选择的星系。250微米和射电选择星系的q_IR之间的差异表明,在~< 100 μ Jy的射电星系中,恒星形成提供了大部分的红外光度,而在mJy区域的星系中,则较少。对于24微米的样本,射电光谱指数在0 < z < 3范围内是恒定的,但q_IR表现出稳定下降的初步证据,使得q_IR与(1+z)^(-0.15 +/- 0.03)成比例-显著的演化,跨越了星系形成的时代,对依赖FIR/射电相关的技术具有重大意义。我们与模型预测进行比较,并推测我们可能会看到无线电活动的增加,从而产生无线电背景。

英文摘要:

We investigate the correlation between far-infrared (FIR) and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from the Balloon-borne Large Aperture Submillimetre Telescope (BLAST), Spitzer, the Large Apex BOlometer CamerA (LABOCA), the Very Large Array (VLA) and the Giant Metre-wave Radio Telescope (GMRT) in the Extended Chandra Deep Field South (ECDFS). For a catalogue of BLAST 250-micron-selected galaxies, we re-measure the 70--870-micron flux densities at the positions of their most likely 24-micron counterparts, which have a median [interquartile] redshift of 0.74 [0.25, 1.57]. From these, we determine the monochromatic flux density ratio, q_250 = log_10 (S_250micron / S_1400MHz), and the bolometric equivalent, q_IR. At z ~= 0.6, where our 250-micron filter probes rest-frame 160-micron emission, we find no evolution relative to q_160 for local galaxies. We also stack the FIR and submm images at the positions of 24-micron- and radio-selected galaxies. The difference between q_IR seen for 250-micron- and radio-selected galaxies suggests star formation provides most of the IR luminosity in ~< 100-uJy radio galaxies, but rather less for those in the mJy regime. For the 24-micron sample, the radio spectral index is constant across 0 < z < 3, but q_IR exhibits tentative evidence of a steady decline such that q_IR is proportional to (1+z)^(-0.15 +/- 0.03) - significant evolution, spanning the epoch of galaxy formation, with major implications for techniques that rely on the FIR/radio correlation. We compare with model predictions and speculate that we may be seeing the increase in radio activity that gives rise to the radio background.

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