摘要
铁低电离宽吸收线类星体(Fe Low-ionization Board Absorption Line Quasar,FeLoBALQ)是数量最稀少的类星体子类之一.该类型类星体的辐射将周围的物质猛烈吹开,形成强劲高速的外流,其中以铁为代表的低电离物质,吸收类星体的辐射,产生特征的低电离度铁元素宽线吸收谱.FeLoBALQ外流物质携带的能量之高,足以解释超大质量黑洞质量M与宿主星系核球速度弥散度σ_(*)的M-σ_(*)关系,同时有研究表明FeLoBALQ可能与星暴星系或星系主并合存在伴生关系.然而,迄今为止搜寻到的FeLoBALQ数量有限,难以从统计上验证上述理论.此研究计划在已有类星体大样本中开展大规模的搜寻工作,挖掘已发现类星体中的FeLoBALQ,为FeLoBALQ的进一步研究提供样本基础.使用深度学习中的卷积神经网络(Convolutional Neural Network,CNN)方法,将以往发现的FeLoBALQ光谱作为训练样本,对SDSS(Sloan Digital Sky Survey)DR7Q(Data Release 7 Quasar catalog)中、红移范围为0.8<z<2.125的共50931条类星体光谱进行鉴别,新搜寻到了160条FeLoBALQ光谱.研究发现FeLoBALQ的颜色比一般类星体更红,且以往发现的FeLoBALQ比新发现的稍微偏红;这些差异在蓝端更明显,在中红外波段差异则几乎消失.结合以往研究发现的FeLoBALQ,估计FeLoBALQ在该样本的该红移段内,占类星体总数的比例约为0.43%,此比例略高于以往研究,且可能依然偏小.今后希望将此方法扩展至更大样本如SDSS DR16Q(Data Release 16 Quasar catalog)以发现更多的FeLoBALQ,并使用大样本研究FeLoBALQ与宿主星系恒星形成、星系主并合的关系以及星系与中心超大质量黑洞的协同演化等问题.
The Fe Low-ionization Broad Absorption Line Quasar(FeLoBALQ)is one of the rarest types of all quasars.Quasars blow out the surrounding violently,forming extreme outflows from which low ionized elements e.g.Fe provide the absorbing feature in FeLoBALQ spectra.Carrying high kinetic energy,the outflows of FeLoBALQ may possibly be enough for powering the M-σ_(*) relationship between the supermassive black hole mass M and the host-galaxy bulge velocity dispersion σ_(*).On the other hand,evidence has been found for the co-existence of FeLoBALQ with hosts’starburst or recent major merger.However,the FeLoBALQ sample collected so far is not large enough to stand for these theories statistically.This research focuses on digging out hidden FeLoBALQs from large quasar surveys,forming a FeLoBALQ catalog large enough for statistical and physical analyze.Adopting Convolutional Neural Network(CNN)method,160 FeLoBALQs are newly identified from totally 50931 quasars in the SDSS(Sloan Digital Sky Survey)DR7Q(Data Release 7 Quasar catalog)in the redshift range of 0.8<2<2.125,with previous identified FeLoBALQ spectra as training sample.The FeLoBALQs’color are found redder than normal quasars,and previously identified FeLoBALQs are lightly redder than newly fidentified ones;these differences are more obvious on bluer end than on redder end,and nearly disappear in mid-infrared band.The proportion of FeLoBALQs out of all quasars given is 0.43%,higher than previous prediction,but may still be underestimated.F urther researches may expand this method to larger samples e.g.SDSS DR16Q(Data Release 16 Quasar catalog)for larger FeLoBALQ sample,which may help to answer the questions of the relationship between FeLoBALQ and host galaxy star formation,FeLoBALQ and galaxy major merger,and the co-evolution of galaxies and central supermasive black holes.
作者
何子麒
傅煜铭
吴学兵
何凌雪
HE Zi-qi;FU Yu-ming;WU Xue-bing;HE Ling-xue(Department of Astronomy,School of Physics,Peking University,Beijing 100871;Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871;Leiden Observatory,Leiden University,Leiden NL-2300 RA;Kapteyn Astronomical Institute,University of Groningen,Groningen NL-9700 AV;Graduate School of Engineering,The University of Tokyo,Tokyo 1138656)
出处
《天文学报》
北大核心
2025年第3期112-125,共14页
Acta Astronomica Sinica
基金
国家自然科学基金项目(11927804,12133001)资助。
