EXPLAINING THE [C II]157.7 μm DEFICIT IN LUMINOUS INFRARED GALAXIES-FIRST RESULTS FROM A HERSCHEL/PACS STUDY OF THE GOALS SAMPLE
EXPLAINING THE [C II]157.7 μm DEFICIT IN LUMINOUS INFRARED GALAXIES-FIRST RESULTS FROM A HERSCHEL/PACS STUDY OF THE GOALS SAMPLE
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DOI：
10.1088/0004-637x/774/1/68
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发表时间：
2013-09-01
影响因子：
4.9
通讯作者：
Sturm, E.
中科院分区：
文献类型：
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作者：
Diaz-Santos, T.;Armus, L.;Sturm, E.
我们提出的第一个调查结果的[C II]157.7 μ m的发射线在241个发光红外星系（LIRG），包括大天文台全天LIRG调查（GOALS）的样本，获得与PACS仪器上的赫歇尔空间天文台。GOALS中LIRGs的[C II]亮度L-[C II]范围为10（7）到2 x 10（9）L-圆点。我们发现，随着尘埃平均温度的升高，LIRGs的[CII]/FIR与远红外（FIR）通量密度比有很强的相关性，从10（-2）到10（-4）之间有很强的负相关性。我们发现之间的相关性[C II]/FIR比和9.7 μ m硅酸盐吸收功能的强度，以及与中红外发射区域（西格玛（MIR））的光度表面密度，这表明更温暖，更紧凑的星爆有显着更小的[C II]/FIR比。纯粹的恒星形成LIRG的平均[C II]/FIR近似于4 x 10（-3），而具有低多环芳烃（PAH）等效宽度（EW）的星系，表明活动星系核（AGN）的存在，跨越[C II]/FIR的整个范围。然而，我们表明，即使只考虑纯恒星形成星系，[C II]/FIR比仍然下降了一个数量级，从10（-2）到10-3，与西格玛（MIR）和西格玛（IR），这意味着[C II] 157.7 μ m的光度不是一个很好的指标的星星形成率（SFR）的大多数本地LIRG，因为它与最可能与最年轻的恒星有关的温暖尘埃排放量不成线性关系。此外，即使在LIRGs中，我们在中红外探测到活动星系核，大多数（2/3）的星系显示[C II]/FIR >= 10-3典型的高6.2 μ m PAH EW源，这表明大多数活动星系核没有显着贡献的FIR发射。我们提供了一个经验关系的[C II]/FIR和特定的SFR恒星形成LIRGs。最后，我们提出了预测的基础上观测到的[C II]和FIR光度应该是有用的高红移星系与阿尔马和CCAT未来的调查结果进行比较的星暴的大小。
We present the first results of a survey of the [C II]157.7 mu m emission line in 241 luminous infrared galaxies (LIRGs) comprising the Great Observatories All-sky LIRG Survey (GOALS) sample, obtained with the PACS instrument on board the Herschel Space Observatory. The [C II] luminosities, L-[C II], of the LIRGs in GOALS range from similar to 10(7) to 2 x 10(9) L-circle dot. We find that LIRGs show a tight correlation of [C II]/FIR with far-IR (FIR) flux density ratios, with a strong negative trend spanning from similar to 10(-2) to 10(-4), as the average temperature of dust increases. We find correlations between the [C II]/FIR ratio and the strength of the 9.7 mu m silicate absorption feature as well as with the luminosity surface density of the mid-IR emitting region (Sigma(MIR)), suggesting that warmer, more compact starbursts have substantially smaller [C II]/FIR ratios. Pure star-forming LIRGs have a mean [C II]/FIR similar to 4 x 10(-3), while galaxies with low polycyclic aromatic hydrocarbon (PAH) equivalent widths (EWs), indicative of the presence of active galactic nuclei (AGNs), span the full range in [C II]/FIR. However, we show that even when only pure star-forming galaxies are considered, the [C II]/FIR ratio still drops by an order of magnitude, from 10(-2) to 10-3, with Sigma(MIR) and Sigma(IR), implying that the [C II] 157.7 mu m luminosity is not a good indicator of the star formation rate (SFR) for most local LIRGs, for it does not scale linearly with the warm dust emission most likely associated to the youngest stars. Moreover, even in LIRGs in which we detect an AGN in the mid-IR, the majority (2/3) of galaxies show [C II]/FIR >= 10-3 typical of high 6.2 mu m PAH EW sources, suggesting that most AGNs do not contribute significantly to the FIR emission. We provide an empirical relation between the [C II]/FIR and the specific SFR for star-forming LIRGs. Finally, we present predictions for the starburst size based on the observed [C II] and FIR luminosities which should be useful for comparing with results from future surveys of high-redshift galaxies with ALMA and CCAT.