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arXiv 1106.3565astro-ph.COastro-ph.GA
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Seyfert星系中黑洞生长与恒星形成的关系

The Relationship Between Black Hole Growth and Star Formation in Seyfert Galaxies

Aleksandar M. Diamond-Stanic, George H. Rieke

摘要:

我们给出了塞弗特星系完整样本的黑洞吸积率以及核、扩展和总恒星形成率的估计。利用斯皮策太空望远镜的观测数据,我们用[O IV] 25.89微米发射线测量了活动星系核(AGN)的光度,用11.3微米芳香特征和扩展的24微米连续谱发射测量了恒星形成光度。我们发现,黑洞的生长与主星系中的核(r<1 kpc)恒星形成有很强的相关性,而与扩展(r>1 kpc)恒星形成的相关性很弱。特别是,由11.3微米芳香特征追踪的核恒星形成率(SFR)遵循与黑洞吸积率(BHAR)的关系,其形式为SFR \proptoBHAR^0 .8,观察到的散射为0.5 dex。当在物理匹配的r=1 kpc孔径中包含额外的恒星形成时,这种SFR-BHAR关系仍然存在,形式为SFR \proptoBHAR^0 .6。然而,当考虑总的SFR时,这种关系变得几乎不可辨别。这表明,在局部塞弗特星系中,亚千秒差距和亚千秒差距尺度上的气体之间存在物理联系,与宿主星系中的外部过程无关。它还表明,所观察到的缩放之间的恒星形成和黑洞增长的样本活动星系核将取决于恒星形成是由核或扩展组件。我们估计的综合黑洞和隆起的增长,发生在这些星系,并发现活动星系核的占空比为5-10%将保持黑洞和隆起的质量之间的比例在当地的宇宙。

英文摘要:

We present estimates of black hole accretion rates and nuclear, extended, and total star-formation rates for a complete sample of Seyfert galaxies. Using data from the Spitzer Space Telescope, we measure the active galactic nucleus (AGN) luminosity using the [O IV] 25.89 micron emission line and the star-forming luminosity using the 11.3 micron aromatic feature and extended 24 micron continuum emission. We find that black hole growth is strongly correlated with nuclear (r<1 kpc) star formation, but only weakly correlated with extended (r>1 kpc) star formation in the host galaxy. In particular, the nuclear star-formation rate (SFR) traced by the 11.3 micron aromatic feature follows a relationship with the black hole accretion rate (BHAR) of the form SFR\proptoBHAR^0.8, with an observed scatter of 0.5 dex. This SFR-BHAR relationship persists when additional star formation in physically matched r=1 kpc apertures is included, taking the form SFR\proptoBHAR^0.6. However, the relationship becomes almost indiscernible when total SFRs are considered. This suggests a physical connection between the gas on sub-kpc and sub-pc scales in local Seyfert galaxies that is not related to external processes in the host galaxy. It also suggests that the observed scaling between star formation and black hole growth for samples of AGNs will depend on whether the star formation is dominated by a nuclear or extended component. We estimate the integrated black hole and bulge growth that occurs in these galaxies and find that an AGN duty cycle of 5-10% would maintain the ratio between black hole and bulge masses seen in the local universe.

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