AKARI detections of for dust in luminous infrared galaxles. Search Tot dusty active galactic nuclei
AKARI detections of for dust in luminous infrared galaxles. Search Tot dusty active galactic nuclei
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AKARI 检测发光红外星系中的尘埃。
DOI：
10.1051/0004-6361/201014221
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发表时间：
2011
影响因子：
6.5
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
Oyabu;S.;et al
目标：我们提出了使用 AKARI 中红外 (MIR) 全天巡天目录识别的活动星系核 (AGN) 的新样本。我们的 MIR 搜索具有检测因消光而在光波长处被遮挡的 AGN 的优点。方法。我们首先选择 F(9μm)/F(KS) > 2 的 AKARI 9μm 多余源，其中 KS 幅度取自两微米全天巡天。然后，我们通过 AKARI/IRC 获得了后续近红外光谱，以确认过量是由热尘埃引起的。我们还利用利克天文台 Shane 3 米望远镜上的卡斯特双摄谱仪获得了光学光谱。结果。根据这些观测结果，我们在两个发光红外星系中检测到了特征温度≳500 K 的热尘埃。这些热尘埃被怀疑与活动星系核有关，活动星系核的非恒星活动不是在光学波段，而是在近红外和中红外波段，即它们隐藏着埋藏的活动星系核。与光学选择的 AGN 群中的宿主星系相比，宿主星系的恒星质量约为 4−6 × 109M⊙。之前的巡天观测都遗漏了这些天体，这证明了 AKARI MIR 全天巡天任务在扩大 AGN 搜索范围以包括更多被严重遮挡的天体方面的能力。根据我们目前的数据，不能完全排除多个具有大质量恒星的尘埃星团的存在。
Aims.We present a new sample of active galactic nuclei (AGNs) identified using the catalog of the AKARI Mid-infrared (MIR) All-Sky Survey. Our MIR search has the advantage of detecting AGNs that are obscured at optical wavelengths by extinction.Methods.We first selected AKARI 9μm excess sources withF(9μm)/F(KS) > 2 whereKSmagnitudes were taken from the Two Micron All Sky Survey. We then obtained follow-up near-infrared spectroscopy with the AKARI/IRC to confirm that the excess is caused by hot dust. We also obtained optical spectroscopy with the Kast Double Spectrograph on the Shane 3-m telescope at Lick Observatory.Results.On the basis of these observations, we detected hot dust with a characteristic temperature of ≳ 500 K in two luminous infrared galaxies. The hot dust is suspected to be associated with AGNs that exhibit their nonstellar activity not in the optical, but in the near- and mid-infrared bands, i.e., they harbor buried AGNs. The host galaxy stellar masses of ~4−6 × 109M⊙are small compared with the hosts in optically-selected AGN populations. These objects were missed by previous surveys, demonstrating the power of the AKARI MIR All-Sky Survey to widen AGN searches to include more heavily obscured objects. The existence of multiple dusty star clusters with massive stars cannot be completely ruled out with our current data.