Is there any evidence that ionized outflows quench star formation in type 1 quasars at z < 1?
Is there any evidence that ionized outflows quench star formation in type 1 quasars at z < 1?
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DOI：
10.1051/0004-6361/201526694
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发表时间：
2015-06
影响因子：
6.5
通讯作者：
B. Balmaverde;B. Balmaverde;A. Marconi;A. Marconi;M. Brusa;M. Brusa;S. Carniani;G. Cresci;E. Lusso;R. Maiolino;F. Mannucci;T. Nagao
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文献类型：
--
作者：
B. Balmaverde;B. Balmaverde;A. Marconi;A. Marconi;M. Brusa;M. Brusa;S. Carniani;G. Cresci;E. Lusso;R. Maiolino;F. Mannucci;T. Nagao
本文的目的是测试 AGN 负反馈的基本模型。根据这个模型，一旦中心黑洞在爱丁顿极限处吸积并达到一定的临界质量，活动星系核驱动的外流就会喷出气体，抑制宿主星系中的恒星形成和自我调节的黑洞生长。我们考虑从赫歇尔在红外波段观察到的 z<1 处的 SDSS 中选出的 224 个类星体样本。我们评估了与由 [OIII]4959,5007 和 [OII]3726,3729 发射线追踪的几个流出特征相关的恒星形成速率，这些特征在大约一半的高质量光谱样本中进行。大多数类星体在[OIII]中显示出不对称且宽阔的翼，我们将其解释为流出特征。我们使用三种不同的标准将类星体分为两组，“弱”和“强”流出。当我们比较两组中五个红移箱的平均恒星形成率时，我们发现强烈流出类星体的恒星形成率相当或稍大。我们通过 SED 拟合估计了恒星质量，类星体沿着恒星形成主序分布，尽管分散度很大。该关系的散射与流出的运动学特性不相关。此外，对于在红外中以星暴或活动星系核发射为主的类星体，我们没有发现恒星形成速率和流出速度之间存在任何相关性，这是先前文献中报道的纯星暴星系的趋势。我们的结论是，基本的 AGN 负反馈情景似乎与我们的结果不一致。尽管我们使用了大量类星体样本，但我们没有发现任何证据表明恒星形成速率在活动星系核驱动的大规模流出的情况下受到抑制。一种可能性是，反馈在比类星体活动的单次事件更长的时间尺度上有效。
The aim of this paper is to test the basic model of negative AGN feedback. According to this model, once the central black hole accretes at the Eddington limit and reaches a certain critical mass, AGN driven outflows blow out gas, suppressing star formation in the host galaxy and self-regulating black hole growth. We consider a sample of 224 quasars selected from the SDSS at z<1 observed in the infrared band by Herschel. We evaluate the star formation rate in relation to several outflow signatures traced by the [OIII]4959,5007 and [OII]3726,3729 emission lines in about half of the sample with high quality spectra. Most of the quasars show asymmetric and broad wings in [OIII], which we interpret as outflow signatures. We separate the quasars in two groups, ``weakly'' and ``strongly'' outflowing, using three different criteria. When we compare the mean star formation rate in five redshift bins in the two groups, we find that the SFRs are comparable or slightly larger in the strongly outflowing quasars. We estimate the stellar mass from SED fitting and the quasars are distributed along the star formation main sequence, although with a large scatter. The scatter from this relation is uncorrelated with respect to the kinematic properties of the outflow. Moreover, for quasars dominated in the infrared by starburst or by AGN emission, we do not find any correlation between the star formation rate and the velocity of the outflow, a trend previously reported in the literature for pure starburst galaxies. We conclude that the basic AGN negative feedback scenario seems not to agree with our results. Although we use a large sample of quasars, we did not find any evidence that the star formation rate is suppressed in the presence of AGN driven outflows on large scale. A possibility is that feedback is effective over much longer timescales than those of single episodes of quasar activity.