Star Formation and AGN Activity in Galaxies Classified Using the 1.6 μm Bump and PAH Features at z = 0.4-2
Star Formation and AGN Activity in Galaxies Classified Using the 1.6 μm Bump and PAH Features at z = 0.4-2
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DOI：
10.1093/pasj/64.4.70
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发表时间：
2011-12
影响因子：
2.3
通讯作者：
H. Hanami;T. Ishigaki;N. Fujishiro;Kouichiro Nakanishi;T. Miyaji;M. Krumpe;K. Umetsu;Y. Ohyama;H. Shim;M. Im;Hyoung Mok Lee;Myung Gyoon Lee;S. Serjeant;G. White;C. Willmer;T. Goto;S. Oyabu;T. Takagi;T. Wada;H. Matsuhara
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作者：
H. Hanami;T. Ishigaki;N. Fujishiro;Kouichiro Nakanishi;T. Miyaji;M. Krumpe;K. Umetsu;Y. Ohyama;H. Shim;M. Im;Hyoung Mok Lee;Myung Gyoon Lee;S. Serjeant;G. White;C. Willmer;T. Goto;S. Oyabu;T. Takagi;T. Wada;H. Matsuhara
我们研究了红移范围z=0.4-2的大质量星系的恒星形成和活动星系核活动，这些星系是利用Akari红外天文卫星和斯巴鲁望远镜向北黄道极(NEP)探测到的。用AKARI/IRC中红外(MIR)多波段光度法跟踪多环芳烃(PAH)发射的恒星形成活动，不仅可以区分恒星形成星系和活动星系核(AGN)，而且可以通过将其通量换算为总发射IR(TIR)光度来估计恒星形成率(SFR)。结合恒星组分的分析，我们研究了恒星形成星系和活动星系核的MIRSED特征，总结如下：(1)从多环芳烃和尘埃环面的发射数据可以很好地示踪恒星形成星系和活动星系核的活动，其中7.7-μm和5-μm发光是很好的示踪剂。(2)对于没有活动星系核的尘埃成星星系，其SFR与恒星质量成正比，单位恒星质量的比SFR(SSFR)随红移而增大。从它们的TIR亮度估计的消光比从它们的光学SED配件估计的消光要大，这可能是由于它们中的尘埃的几何变化造成的。(3)即使对于有活动星系核的尘埃恒星形成星系，减去活动星系核的遮蔽贡献，也可以从它们的TIR发光度中得到Sfr，这表明与没有活动星系核的星系相比，它们的Sfr可能在z≃0.8时熄灭。(4)静止标架5-μm光度的活动星系核活动表明，它们的超大质量黑洞(SMBH)在大多数大质量星系中可能已经增长到≃3×108M⊙，在z>；1.2时有10 11M⊙，并且SMBH与其宿主星系之间的质量关系已经由z≃1-2建立。
We studied the star-formation and AGN activity of massive galaxies in the redshift range z = 0.4-2, which were detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and Subaru telescope toward the North Ecliptic Pole (NEP). The AKARI/IRC Mid-InfraRed (MIR) multiband photometry was used to trace the star-forming activities with Polycyclic Aromatic Hydrocarbon (PAH) emission, which is effective not only to distinguish between star-forming and AGN galaxies, but also to estimate the Star Formation Rate (SFR) with converting its flux to the total emitting IR (TIR) luminosity. In combination with the analyses of the stellar components, we studied the MIR SED features of star-forming and AGN-harboring galaxies, which we summarize below: (1) The rest-frame 7.7-μm and 5-μm luminosities are good tracers of star-forming and AGN activities from their PAH and dusty tori emissions, respectively. (2) For dusty star-forming galaxies without AGN, their SFR shows a correlation that is nearly proportional to their stellar mass, and their specific SFR (sSFR) per unit stellar mass increases with redshift. Extinctions estimated from their TIR luminosities are larger than those from their optical SED fittings, which may be caused by geometric variations of dust in them. (3) Even for dusty star-forming galaxies with AGN, SFRs can be derived from their TIR luminosities with subtraction of the obscured AGN contribution, which indicates that their SFRs were possibly quenched around z ≃ 0.8 compared with those without AGN. (4) The AGN activity from their rest-frame 5-μm luminosity suggests that their Super Massive Black Holes (SMBHs) could already have grown to ≃ 3 × 10 8 M ⊙ in most massive galaxies with 10 11 M ⊙ at z > 1.2, and the mass relation between SMBHs and their host galaxies has already become established by z ≃ 1-2.