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arXiv 0811.1533astro-ph
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来自斯皮策通量限制样品的平均红外星系光谱

Average Infrared Galaxy Spectra From Spitzer Flux Limited Samples

Daniel W. Weedman, James R. Houck

摘要:

本文报道了一个fv(24 μ m)> 10 mJy的限流星系样品的中红外光谱分析。观测到的源来自斯皮策首视巡天(FLS)目录和位于牧夫座的NOAO深宽视场巡天(NDWFS)区域。光谱样本包括这些组合星表中fv(24 μ m)> 10 mJy的100个源中的60个。新的光谱从斯皮策红外光谱仪提出了25 FLS源和11牧夫座活动星系核,这些结合24牧夫座星爆星系以前公布的,以确定中红外光谱特征的分布为总10毫焦样本。源具有0.01 < z < 2.4和41.8 < log vLv(15 um)< 46.2(ergs/s)。平均光谱被确定为光度的函数;低光度源(log vLv(15 μ m)< 44.0)由PAH特征主导,而高光度源(log vLv(15 μ m)> 44.0)由硅酸盐吸收或发射主导。我们发现,0.4微米的静止帧等效宽度为6.2微米的PAH发射功能提供了一个很好的划分低光度,“纯”星爆和高光度AGN或复合源。使用平均光谱,通量fv(24 μ m),这将与斯皮策MIPS观察到的预测作为红移的函数的源的亮度,对应于平均光谱。在z = 3时,fv(24 μ m)> 1 mJy,可以看到与10 mJy样品相同的活动星系核,但在z = 0.5时,星爆下降到fv(24 μ m)< 1 mJy。这表明,恒星爆发的光度演化需要大量的解释在其他IRS结果中发现的fv(24 um)> 1 mJy和z ~ 2的恒星爆发。

英文摘要:

The mid-infrared spectroscopic analysis of a flux-limited sample of galaxies with fv(24um) > 10 mJy is presented. Sources observed are taken from the Spitzer First Look Survey (FLS) catalog and from the NOAO Deep Wide-Field Survey region in Bootes (NDWFS). The spectroscopic sample includes 60 of the 100 sources in these combined catalogs having fv(24um) > 10 mJy. New spectra from the Spitzer Infrared Spectrograph are presented for 25 FLS sources and for 11 Bootes AGN; these are combined with 24 Bootes starburst galaxies previously published to determine the distribution of mid-infrared spectral characteristics for the total 10 mJy sample. Sources have 0.01 < z < 2.4 and 41.8 < log vLv(15um) < 46.2 (ergs/s). Average spectra are determined as a function of luminosity; lower luminosity sources (log vLv(15um) < 44.0) are dominated by PAH features and higher luminosity sources (log vLv(15um) > 44.0) are dominated by silicate absorption or emission. We find that a rest frame equivalent width of 0.4um for the 6.2um PAH emission feature provides a well defined division between lower luminosity, "pure" starbursts and higher luminosity AGN or composite sources. Using the average spectra, fluxes fv(24um) which would be observed with the Spitzer MIPS are predicted as a function of redshift for sources with luminosities that correspond to the average spectra. AGN identical to those in this 10 mJy sample could be seen to z = 3 with fv(24um) > 1 mJy, but starbursts fall to fv(24um) < 1 mJy by z ~ 0.5. This indicates that substantial luminosity evolution of starbursts is required to explain the numerous starbursts found in other IRS results having fv(24um) > 1 mJy and z ~ 2.

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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