The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability
C. J. Grier, P. B. Hall, W. N. Brandt, J. R. Trump, Yue Shen, M. Vivek, N. Filiz Ak, Yuguang Chen, K. S. Dawson, K. D. Denney, Paul. J. Green, Linhua Jiang, C. … 展开作者
C. J. Grier, P. B. Hall, W. N. Brandt, J. R. Trump, Yue Shen, M. Vivek, N. Filiz Ak, Yuguang Chen, K. S. Dawson, K. D. Denney, Paul. J. Green, Linhua Jiang, C. S. Kochanek, Ian D. McGreer, I. Pâris, B. M. Peterson, D. P. Schneider, Charling Tao, W. M. Wood-Vasey, Dmitry Bizyaev, Jian Ge, Karen Kinemuchi, Daniel Oravetz, Kaike Pan, Audrey Simmons
我们报道了在类星体SDSS J141007.74+541203.3中发现的高速CIV宽吸收线槽的快速变化。该天体于2014年作为斯隆数字巡天混响映射项目的一部分被集中观测,在此期间,重子振荡光谱巡天摄谱仪获得了32个光谱时代。我们观察到宽(~4000 km/s宽)CIV槽的等效宽度在休息帧时间尺度上的显著(> 4 sigma)变化,短至1.20天(~29小时),这是迄今为止报道的最短的宽吸收线变化时间尺度。在这些短时间尺度上,等效宽度的变化约为10%,在战役持续期间约为2倍。我们评估了几个潜在的原因的变化,得出的结论是,最可能的原因是一个快速响应事件电离连续的变化。如果流出的半径处复合率高于电离率,则变化的时间尺度将吸收气体密度的下限设为n_e > 3.9 x 10^5 cm^-3。这种类星体的宽吸收线变化特性与以前的类星体研究中观察到的一致,表明这种短期变化实际上可能是常见的,因此可以用来了解流出特性和对类星体/宿主星系反馈情景的贡献。
英文摘要:
We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4sigma) variability in the equivalent width of the broad (~4000 km/s wide) CIV trough on rest-frame timescales as short as 1.20 days (~29 hours), the shortest broad absorption line variability timescale yet reported. The equivalent width varied by ~10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n_e > 3.9 x 10^5 cm^-3. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.
We present the results of a pilot Hubble Space Telescope (HST) imaging study of the host galaxies of ten quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Probing more than an order of magnitude in BH and stellar masses, our sample is the first statistical sample to study the BH-host correlations beyond z>0.3 with reliable BH masses from reverberation mapping rather than from single-epoch spectroscopy. We perform image decomposition in two HST bands (UVIS-F606W and IR-F110W) to measure host colors and estimate stellar masses using empirical relations between br…
The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) program monitors 849 active galactic nuclei (AGN) both spectroscopically and photometrically. The photometric observations used in this work span over four years and provide an excellent baseline for variability studies of these objects. We present the photometric light curves from 2014 to 2017 obtained by the Steward Observatory's Bok telescope and the CFHT telescope with MegaCam. We provide details on the data acquisition and processing of the data from each telescope, the difference imaging photometry used to produce the light cur…
The Sloan Digital Sky Survey Reverberation Mapping Project: H$α$ and H$β$ Reverberation Measurements From First-year Spectroscopy and Photometry
我们目前的混响映射结果从斯隆数字巡天混响映射项目的第一年的光谱和光度观测相结合。我们成功地恢复了共44个类星体的$g+i$带发射和宽H $β$发射线之间的混响时间延迟,以及18个类星体的宽H $α$发射线。使用JAVELIN和CREAM软件和传统的内插互相关联函数(ICCF)计算时间延迟:使用定义明确的标准,我们报告了用JAVELIN测量32 H $β$和13 H $α$滞后,用CREAM测量42 H $β$和17 H $α$滞后,以及用ICCF测量16 H $β$和8 H $α$滞后.三种方法之间的滞后值通常是一致的,尽管我们通常使用JAVELIN和CREAM测量的不确定性比ICCF小,因为前两种方法具有更强的物理动机光曲线插值和更强大的统计建模。我们的H $β$探测到的类星体样本的红移中值为0.53,明显高于以前的混响映射样本。我们发现,在大多数对象中,H $α$发射的时间延迟是一致的或略长于H $β$。我们测量黑洞质量使用我们测量的时间延迟和线宽为这些类星体。这些黑洞质量的测量大多与基于局部M-sigma关系的预期一致,并且也与单历元黑洞质量测量一致。这项工作将混响映射活动星系的当前样本大小增加了约三分之二,并代表了本地宇宙(z < 0.3)以外的混响映射观测的第一个大样本。
Effects of heterogeneous data sets and time-lag measurement techniques on cosmological parameter constraints from MgII and CIV reverberation-mapped quasar data
We present reverberation mapping results for the MgII 2800 A broad emission line in a sample of 193 quasars at 0.35<z<1.7 with photometric and spectroscopic monitoring observations from the Sloan Digital Sky Survey Reverberation Mapping project during 2014 - 2017. We find significant time lags between the MgII and continuum lightcurves for 57 quasars and define a "gold sample" of 24 quasars with the most reliable lag measurements. We estimate false-positive rates for each lag that range from 1-24%, with an average false-positive rate of 11% for the full sample and 8% for the gold sample. There…
Reverberation mapping (RM) of active galactic nuclei (AGNs) has been used over the past three decades to determine AGN broad-line region (BLR) sizes and central black-hole masses, and their relations with the AGN's luminosity. Until recently the sample of objects with RM data was limited to low-luminosity AGNs ($L_{\rm opt} \lesssim 10^{46}$ ergs s$^{-1}$) and low redshifts ($z \lesssim 0.5$). Here we present results from a reverberation-mapping project of some of the most luminous and highest redshift quasars that have been mapped to date. The study is based on almost twenty years of photomet…
Quasar broad emission lines are largely powered by photoionization from the accretion continuum. Increased central luminosity will enhance line emissivity in more distant clouds, leading to increased average distance of the broad-line-emitting clouds and decreased averaged line width, known as the broad-line region (BLR) "breathing". However, different lines breathe differently, and some high-ionization lines, such as C IV, can even show "anti-breathing" where the line broadens when luminosity increases. Using multi-year photometric and spectroscopic monitoring data from the Sloan Digital Sky …
It is well known that reverberation mapping of active galactic nuclei (AGN) reveals a relationship between AGN luminosity and the size of the broad-line region, and that use of this relationship, combined with the Doppler width of the broad emission line, enables an estimate of the mass of the black hole at the center of the active nucleus based on a single spectrum. An unresolved key issue is the choice of parameter used to characterize the line width, either FWHM or line dispersion (the square root of the second moment of the line profile). We argue here that use of FWHM introduces a bias, s…
We present the statistical methods that have been developed to analyse the OzDES reverberation mapping sample. To perform this statistical analysis we have created a suite of customisable simulations that mimic the characteristics of each source in the OzDES sample. These characteristics include: the variability in the photometric and spectroscopic lightcurves, the measurement uncertainties, and the observational cadence. By simulating the sources in the OzDES sample that contain the CIV emission line, we developed a set of criteria that rank the reliability of a recovered time lag depending o…
Continuum Reverberation in Bright Quasars Using NASA/ATLAS
Research School of Astronomy and Astrophysics, Australian National University(澳大利亚国立大学天文与天体物理研究学院);Centre for Gravitational Astrophysics (CGA), Australian National University(澳大利亚国立大学引力天体物理学中心);Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast(贝尔法斯特女王大学数学与物理学院天体物理研究中心);Research Center for Space and Cosmic Evolution, Ehime University(爱媛大学宇宙演化研究中心);University of Belgrade-Faculty of Mathematics, Department of Astronomy(贝尔格莱德大学数学系天文学系);Millennium Institute of Astrophysics (MAS)(天体物理学千年研究所);Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile(智利天主教Pontificia大学物理学院天体物理研究所)
We measure the correlation between black-hole mass $M_{\rm BH}$ and host stellar mass $M_*$ for a sample of 38 broad-line quasars at $0.2\lesssim z\lesssim 0.8$ (median redshift $z_{\rm med}=0.5$). The black-hole masses are derived from a dedicated reverberation mapping program for distant quasars, and the stellar masses are estimated from two-band optical+IR HST imaging. Most of these quasars are well centered within $\lesssim 1$kpc from the host galaxy centroid, with only a few cases in merging/disturbed systems showing larger spatial offsets. Our sample spans two orders of magnitude in stel…
We use multi-epoch quasar spectroscopy to determine how accurately single-epoch spectroscopy can locate quasars in emission-line parameter space in order to inform investigations where time-resolved spectroscopy is not available. We explore the improvements in emission-line characterization that result from using non-parametric information from many lines as opposed to a small number of parameters for a single line, utilizing reconstructions based on an independent component analysis applied to the data from the Sloan Digital Sky Survey Reverberation Mapping project. We find that most of the q…
Broad absorption line disappearance and emergence using multiple-epoch spectroscopy from the Sloan Digital Sky Survey
我们研究宽吸收线(BAL)的消失和出现使用470 BAL-quasar样本在< 0.10-5.25休息帧年,至少有三个光谱历元的每个类星体从斯隆数字巡天。我们确定了与CIV 1548、1550和/或SiIV 1393、1402双联体相关的14个在< 1.73-4.62休息帧年内消失的BALs和18个在< 1.46-3.66休息帧年内出现的BALs,并报告了它们的变异性行为。在我们的数据集中,BAL类星体以2.3%和3.0%的速度分别显示出消失/出现的CIV BALs,BAL到非BAL类星体过渡的频率为1.7%。我们检测到平均< 3.88个休息帧年的4个重新出现的BALs和平均< 4.15个休息帧年的3个重新消失的BALs,这是这些类型的首次报道。我们推断BAL寿命沿视线名义上是< 100-1000年使用消失的CIV BALs在我们的样品。解释(重新)出现和(重新)消失的BALs揭示的证据,共同支持横向运动和电离变化的情况下,解释BAL的变化。我们使用电离变化方案将标称CIV/SiIV BAL流出位置限制为< 100 pc from the central source and a radial size of >1 × 10 ^-7 pc(0.02 au),使用横向运动方案将标称流出位置限制为< 0.5 pc,横向尺寸限制为~0.01 pc。我们的研究结果与以前的工作是一致的…
The Sloan Digital Sky Survey Reverberation Mapping Project: Investigation of Continuum Lag Dependence on Broad-Line Contamination and Quasar Properties
We present a survey of extremely high-velocity outflows (EHVOs) in quasars, defined by speeds between 0.1c and 0.2c. This region of the parameter space has not been included in previous surveys, but it might present the biggest challenge for theoretical models and it might be a large contributor to feedback due to the outflows' potentially large kinetic power. Using the Sloan Digital Sky Survey, we find 40 quasar spectra with broad EHVO CIV absorption, 10 times more than the number of previously known cases. We characterize the EHVO absorption and find that in 26 cases, CIV is accompanied by N…
Zooming into the broad line region of the gravitationally lensed quasar Q2237+0305 = the Einstein Cross: III. Determination of the size and structure of the CIV and CIII] emitting regions using microlensing
AGN Reverberation Mapping with LITMUS: Fundamental Limits on lag Recovery Rates
University of Queensland(昆士兰大学);Macquarie University(麦考瑞大学);The Ohio State University(俄亥俄州立大学);Stanford University(斯坦福大学);Australian National University(澳大利亚国立大学);The University of Sydney(悉尼大学)
The Pennsylvania State University(宾夕法尼亚州立大学);Vanderbilt University(范德堡大学);Fisk University(菲斯克大学);Università degli Studi di Milano-Bicocca(米兰比可卡大学);INAF - Osservatorio Astronomico di Brera(意大利国家天体物理研究所布拉拉天文台);INFN, Sezione di Milano-Bicocca(意大利国家核物理研究所米兰比可卡分部)