We present preliminary results from an investigation into broad absorption line (BAL) variability within a sample of 41 radio-loud quasars (RLQs). Using 28 new Hobby-Eberly Telescope (HET) spectra along with earlier Sloan Digital Sky Survey (SDSS) or other archival data, we generate a total set of 50 pairs of BAL equivalent width measurements. Absorption variability in BAL RLQs typically consists of modest changes in the depth of trough segments, and variability is more common on longer rest-frame timescales; these tendencies are similar to previous findings for BAL radio-quiet quasars (RQQs). BAL variability in RLQs does not show any obvious dependence upon radio luminosity or loudness, but there is suggestive support for greater fractional variability within lobe-dominated RLQs.
Evidence has accumulated suggesting the clustering of radio loud quasars is greater than for radio quiet quasars. We interpret these results in a context in which the fraction of radio loud quasar formation is less than or equal to that for radio quiet quasars for all environments and redshift. Because we assume that post-merger cold gas onto large black holes produces either a radio loud or a radio quiet quasar, we show that for largest black hole masses that live in largest dark matter halos, fRLQ approaches 0.5 from below but does not exceed it, such that in rich clusters the formation of a…
We present the study on the X-ray emission for a sample of radio-detected quasars constructed from the cross-matches between SDSS, FIRST catalogs and XMM-Newton archives. A sample of radio-quiet SDSS quasars without FIRST radio detection is also assembled for comparison. We construct the optical and X-ray composite spectra normalized at rest frame $4215\,\rm Å$ (or $2200\,\rm Å$) for both radio-loud quasars (RLQs) and radio-quiet quasars (RQQs) at $z\le3.2$, with matched X-ray completeness of 19\%, redshift and optical luminosity. While the optical composite spectrum of RLQs is similar to that…
Recent work on red and blue quasi-stellar objects (QSOs) has identified peculiar number distributions as a function of radio loudness that we explore and attempt to explain from the perspective of a picture in which a subset of the population of active galaxies evolves from the radio loud to the radio quiet state. Because the time evolution is slowed down by an order of magnitude or more for the radio quiet phase, the numbers of red and blue QSOs approach each other at the extreme end of the radio quiet range of radio loudness with larger numbers. The rapid time evolution of most radio loud ph…
Disclosing the Radio Loudness Distribution Dichotomy in Quasars: An Unbiased Monte Carlo Approach Applied to the SDSS-FIRST Quasar Sample
我们调查的二分法的射电响度分布的类星体通过模拟他们的无线电发射和各种选择的影响，使用蒙特卡罗方法。两个物理上不同的类星体群体的存在，射电响亮和射电安静类星体，是有争议的，在过去的十年中，类星体射电响度的双峰分布既被肯定又有争议。我们用简单的单峰和双峰分布函数模拟类星体的射电光度分布。将得到的模拟样本与从SDSS DR 7类星体目录中提取的8，300个类星体的基准样本进行比较，并与FIRST调查的射电观测相结合。我们的研究结果表明，SDSS-FIRST样本最好由两个分量组成的无线电响度分布来描述，其中12+/-1%的源位于无线电响度分量中。另一方面，在响度分布（双峰）的局部最小值的证据并不强，我们发现，以前的索赔，其存在可能受到影响的第一次调查的不完整性接近其微弱的限制。我们还调查了红移和亮度依赖的射电响度分布，并发现初步证据表明，在高红移射电响亮类星体是罕见的，平均“响亮”，并表现出较小的范围内的射电响度。与最近的其他工作一致，我们得出结论，SDSS-FIRST样本强烈表明类星体的射电响度分布不是一个普适函数，需要比这里提出的更复杂的模型来充分解释现有的观测结果。
We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected by van Velzen et al. with the SDSS DR7 catalog of quasars. Covering factors of FR II quasars are compared with covering factors of the radio-quiet quasars matched with them in redshift, black hole mass, and Eddington-ratio. We found that covering factors, proxied by the infrared-to-bolometric luminosity ratio, are on average slightly smaller in FR II quasar…
We performed a study of high redshift ($z>2$) quasars, looking for the main differences between Radio Loud Quasars (RLQ) and Radio Quiet Quasars (RQQ) in the X-ray band. Our sample of 472 RQQ and 81 RLQ was selected by cross-matching the SDSS DR7 quasars catalog with the Chandra Source Catalog. We computed the X-ray luminosity for the two samples and confirmed the X-ray luminosity excess of RLQ over RQQ. We fit the X-ray spectra assuming the absorbed power law model and obtained the photon index ($Γ$) values for all the sources in the sample. We excluded quasars with a low number of counts ($<…
We report on the Swift/XRT observation and classification of eleven blazar candidates at $z>4$. These sources were selected as part of a sample of extremely radio-loud quasars, in order to focus on quasars with jets oriented roughly close to our line-of-sight. Deriving their viewing angles and their jets bulk Lorentz factors was crucial for a strict blazar classification, and it was possible only thanks to X-ray observations. Out of eleven sources, five show strong and hard X-ray fluxes, that allow their blazar classification, two are uncertain, three host relativistic jets that we observe jus…
Outflows of photoionized gas are commonly detected in the X-ray spectra of Seyfert 1 galaxies. However, the evidence for this phenomenon in broad line radio galaxies, which are analogous to Seyfert 1 galaxies in the radio-loud regime, has so far been scarce. Here, we present the analysis of the X-ray absorption in the radio-loud quasar 4C +74.26. With the aim of characterizing the kinetic and the ionization conditions of the absorbing material, we fitted jointly the XMM-Newton Reflection Grating Spectrometer (RGS) and the Chandra High Energy Transmission Grating Spectrometer (HETGS) spectra, w…
We present a study of a sample of 223 radio-loud quasars (up to redshift $<$0.3) in order to investigate their spectral properties. Twenty-six of these radio-loud quasars are identified as Flat Spectrum Radio Quasars (FSRQs) and fifty-four are identified as Steep Spectrum Radio Quasars (SSRQs) based on their radio spectral index. We study the [O III] line properties of these quasars to investigate the origin and properties of blue wings (shift of the profile towards lower wavelengths) and blue outliers (shift of the whole spectroscopic feature). Most of the quasars show blue wings with velocit…
We have investigated the jet-linked \mbox{X-ray} emission from highly radio-loud quasars (HRLQs; $\log R>2.5$) at high redshift. We studied the X-ray properties of 15 HRLQs at $z>4$, using new {\it Chandra} observations for six objects and archival {\it XMM-Newton} and {\it Swift} observations for the other nine. We focused on testing the apparent enhancement of jet-linked \mbox{X-ray} emission from HRLQs at $z>4$. Utilizing an enlarged (24 objects) optically flux-limited sample with complete X-ray coverage, we confirmed that HRLQs at $z>4$ have enhanced X-ray emission relative to that of HRLQ…
We examine the fundamental plane of black hole activity for correlations with redshift and radio loudness in both radio-loud and radio-quiet quasar populations. Sources are compiled from archival data of both radio-loud and radio-quiet quasars over redshifts $0.1 < z < 5.0$ to produce a sample of 353 sources with known X-ray, radio, and black hole mass measurements. A fundamental plane of accretion activity is fit to a sample of radio-loud and radio-quiet quasars, and we find a dichotomy between radio-loud and radio-quiet sources. The set of best-fit equations that best describe the two sample…
Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the HeII EW and $α_{\rm{ox}}$ in RQQs are strongly correlated, which suggests that their extreme-ultraviolet (EUV) and X-ray emission mechanisms are tightly related. Using 48 RLQs, we show that steep-spectrum radio quasars (SSRQs) and low radio-luminosity ($L_{\rm R}$) flat-spectrum radio quasars (FSRQs) follow the $α_{\rm ox}$--HeII EW relation of RQQs. This suggests that the X-ray and EUV emis…
The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Here, we present the hard X-ray NuSTAR observations of the radio-loud quasar 4C 74.26 in a joint analysis with quasi-simultaneous, soft X-ray Swift observations. Ou…
Radio-loud quasars (RLQs) are more X-ray luminous than predicted by the X-ray-optical/UV relation (i.e. $L_\mathrm{x}\propto L_\mathrm{uv}^γ$) for radio-quiet quasars (RQQs). The excess X-ray emission depends on the radio-loudness parameter ($R$) and radio spectral slope ($α_\mathrm{r}$). We construct a uniform sample of 729 optically selected RLQs with high fractions of X-ray detections and $α_\mathrm{r}$ measurements.We find that steep-spectrum radio quasars (SSRQs; $α_\mathrm{r}\le-0.5$) follow a quantitatively similar $L_\mathrm{x}\propto L_\mathrm{uv}^γ$ relation as that for RQQs, suggest…
We present X-ray spectral and long-term variability analyses of an unbiased sample of 361 optically selected radio-loud quasars (RLQs) utilizing sensitive serendipitous X-ray data from the Chandra and XMM-Newton archives. The spectral and temporal properties of RLQs are compared with those of radio-quiet quasars (RQQs) matched in $L_\mathrm{2500A}$ and $z$. The median power-law photon index ($Γ$) of RLQs is $1.84^{+0.01}_{-0.01}$, which is close to that of matched RQQs ($1.90^{+0.02}_{-0.01}$). No significant correlations between $Γ$ and radio-loudness, $L_\mathrm{x}/L_\mathrm{x,rqq}$ (the X-r…
We present VLT/SINFONI observations of 35 quasars at 2.1 < z < 3.2, the majority of which were selected from the Clusters Around Radio-Loud AGN (CARLA) survey. CARLA quasars have large CIV-based black hole (BH) masses (M(BH) > 10^9 Msun) and powerful radio emission (P(500MHz) > 27.5 W/Hz). We estimate Ha-based M(BH), finding a scatter of 0.35 dex compared to CIV. We evaluate several recipes for correcting CIV-based masses, which reduce the scatter to 0.24 dex. The radio power of the radio-loud quasars is at most weakly correlated with the interconnected quantities Ha-width, L(5100A) and M(BH),…
High-redshift radio sources provide plentiful opportunities for studying the formation and evolution of early galaxies and supermassive black holes. However, the number of known radio-loud active galactic nuclei (AGN) above redshift 4 is rather limited. At high redshifts, it appears that blazars, with relativistically beamed jets pointing towards the observer, are in majority compared to radio-loud sources with jets misaligned with respect to the line of sight. To find more of these misaligned AGN, milliarcsec-scale imaging studies carried out with very long baseline interferometry (VLBI) are …
To understand the impact of active galactic nuclei (AGN) on their host galaxies and large scale environment it is crucial to determine their total radiative power across all wavelengths (i.e., bolometric luminosity). In this contribution we describe how quasar accretion disk spectral energy distribution (SED) templates, parameterized by the black hole (BH) mass, Eddington ratio, and spin can be used to estimate their total radiated luminosity. To estimate the bolometric luminosity of AGN, we integrate the accretion disk SEDs from 1$μ$m to 10keV. Our approach self-consistently covers any gaps i…
Jet launching in radio loud (RL) quasars is one of the fundamental problems in astrophysics. Exploring the differences in the inner accretion disk properties between RL and radio quiet (RQ) quasars might yield helpful clues to this puzzle. We previously discovered that the shorter term UV/optical variations of quasars are bluer than the longer term ones, i.e., the so-called timescale-dependent color variation. This is consistent with the scheme that the faster variations come from the inner and hotter disk regions, thus providing a useful tool to map the accretion disk which is otherwise unres…
