Mid-infrared spectroscopy of infrared-luminous galaxies at z~0.5-3
A. Hernan-Caballero, I. Perez-Fournon, E. Hatziminaoglou, A. Afonso-Luis, M. Rowan-Robinson, D. Rigopoulou, D. Farrah, C. J. Lonsdale, T. Babbedge, D. Clements,… 展开作者
A. Hernan-Caballero, I. Perez-Fournon, E. Hatziminaoglou, A. Afonso-Luis, M. Rowan-Robinson, D. Rigopoulou, D. Farrah, C. J. Lonsdale, T. Babbedge, D. Clements, S. Serjeant, F. Pozzi, M. Vaccari, F. M. Montenegro-Montes, I. Valtchanov, E. Gonzalez-Solares, S. Oliver, D. Shupe, C. Gruppioni, B. Vila-Vilaro, C. Lari, F. La Franca
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32 pages, 24 figures, 15 tables, accepted for publication in MNRAS
我们目前的低分辨率中红外（MIR）光谱的70个红外发光星系获得的红外光谱（IRS）机载斯皮策。我们从欧洲大面积红外巡天（ELAIS）中选择S15 > 0.8 mJy和光度或光谱z > 1的源。大约一半的样本是光学类星体，而其余的源是星系，包括模糊的活动星系核和恒星爆发。我们使用众所周知的红外诊断，以及一个新的，我们建议，分为三种类型的源：那些占主导地位的一个unobscured活动星系核（类星体），模糊活动星系核，和星爆为主的来源。星暴集中在z ~ 0.6-1.0处，这得益于7.7微米的PAH谱带移至选定的15微米谱带，而AGN则分布在0.5 < z < 3.1范围内。恒星形成率（SFR）估计个别来源的PAH功能的光度。从具有可靠红移的所有源的合成光谱中获得了类星体和被遮蔽活动星系核中PAH平均光度的估计。类星体的估计平均SFR为50-100 Mo yr^-1，但隐含的远红外光度比通过对远红外光度学的叠加分析得到的结果低3-10倍，这表明来自活动星系核的高能光子破坏了PAH载体。在类似的MIR光度的类星体中，在被遮蔽的活动星系核中估计的SFR要高2-3倍。这种差异可能不仅仅是由于光度效应或选择偏差，而是可能表明遮蔽和恒星形成之间的联系。然而，观察到的硅酸盐吸收和近中红外光谱的斜率之间的相关性是兼容的活动星系核发射在这些源中产生的尘埃环的遮蔽。
英文摘要：
We present results on low-resolution mid-infrared (MIR) spectra of 70 infrared-luminous galaxies obtained with the Infrared Spectrograph (IRS) onboard Spitzer. We selected sources from the European Large Area Infrared Survey (ELAIS) with S15 > 0.8 mJy and photometric or spectroscopic z > 1. About half of the sample are QSOs in the optical, while the remaining sources are galaxies, comprising both obscured AGN and starbursts. We classify the spectra using well-known infrared diagnostics, as well as a new one that we propose, into three types of source: those dominated by an unobscured AGN (QSOs), obscured AGN, and starburst-dominated sources. Starbursts concentrate at z ~ 0.6-1.0 favored by the shift of the 7.7-micron PAH band into the selection 15 micron band, while AGN spread over the 0.5 < z < 3.1 range. Star formation rates (SFR) are estimated for individual sources from the luminosity of the PAH features. An estimate of the average PAH luminosity in QSOs and obscured AGN is obtained from the composite spectrum of all sources with reliable redshifts. The estimated mean SFR in the QSOs is 50-100 Mo yr^-1, but the implied FIR luminosity is 3-10 times lower than that obtained from stacking analysis of the FIR photometry, suggesting destruction of the PAH carriers by energetic photons from the AGN. The SFR estimated in obscured AGN is 2-3 times higher than in QSOs of similar MIR luminosity. This discrepancy might not be due to luminosity effects or selection bias alone, but could instead indicate a connection between obscuration and star formation. However, the observed correlation between silicate absorption and the slope of the near- to mid-infrared spectrum is compatible with the obscuration of the AGN emission in these sources being produced in a dust torus.
IRMaGiC: Extending Luminous Red Galaxy Selection into the Infrared with Joint Rubin Observatory's Large Survey of Space Time and Roman's High Latitude Imaging Survey
Duke University（杜克大学）；SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；Stanford University（斯坦福大学）
Luminous Infrared Galaxies with the Submillimeter Array: II. Comparing the CO(3-2) Sizes and Luminosities of Local and High-Redshift Luminous Infrared Galaxies
Water megamasers at 22 GHz with a gas disk configuration in galaxies provide the most precise measurements of supermassive black hole masses, as well as independent constraints on the Hubble constant in the nearby universe. The existence of other maser types, such as jet or outflow masers, represents another tracer for AGN science. However, the detection rate of water megamasers in galaxies is extremely low. Over 40 years, only $\sim$ 160 galaxies are found to harbour maser emission, and $\sim$ 30\% of them show features in their maser emission that indicate a disk-like geometry. Therefore, in…
