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We report the results of long-term reverberation mapping (RM) campaigns of the nearby active galactic nuclei (AGN) NGC 4151, spanning from 1994 to 2022, based on archived observations of the FAST Spectrograph Publicly Archived Programs and our new observations with the 2.3m telescope at the Wyoming Infrared Observatory. We reduce and calibrate all the spectra in a consistent way, and derive light curves of the broad H$\beta$ line and 5100\,{\AA} continuum. Continuum light curves are also constructed using public archival photometric data to increase sampling cadences. We subtract the host galaxy contamination using {\it HST} imaging to correct fluxes of the calibrated light curves. Utilizing the long-term archival photometric data, we complete the absolute flux-calibration of the AGN continuum. We find that the H$\beta$ time delays are correlated with the 5100\,{\AA} luminosities as $\tau_{\rm H\beta}\propto L_{5100}^{0.46\pm0.16}$. This is remarkably consistent with Bentz et al. (2013)'s global size-luminosity relationship of AGNs. Moreover, the data sets for five of the seasons allow us to obtain the velocity-resolved delays of the H$\beta$ line, showing diverse structures (outflows, inflows and disks). Combining our results with previous independent measurements, we find the measured dynamics of the H$\beta$ broad-line region (BLR) are possibly related to the long-term trend of the luminosity. There is also a possible additional $\sim$1.86 years time lag between the variation in BLR radius and luminosity. These results suggest that dynamical changes in the BLR may be driven by the effects of radiation pressure., Comment: Accepted for publication in MNRAS; comments welcome!

The inverse relationship between equivalent width (EW) of broad emission lines and the underlying continuum luminosity, known as the Baldwin effect (BE), is an important and well-studied correlation in active galactic nuclei (AGNs). However, the EW is also considered to be anticorrelated with the Eddington ratio, referred to as the modified Baldwin effect (MBE). Investigating whether the BE or MBE is the stronger correlation is important for studying the ionization mechanism and the broad-line region of AGN. Based on a sample of 85 bright quasars with quasi-simultaneous ultraviolet (UV)-optical spectra and a redshift range of 0.03–1.404 from Shang et al., we first present line fitting and measurements of the O vi line that were not previously available and the Si iv + O iv] line. We then investigate and compare the BE and MBE of multiple UV and optical emission lines from this single sample. We find that the BE of most of the broad emission lines is stronger than the MBE. Furthermore, we confirm the previous result that the slope of the BE steepens with the ionization energy of the line, and also find that the MBE slope shows a similar trend. In addition, compared with the C iv line, the O vi shows a broader line width and a larger peak velocity blueshift with respect to the systemic redshift. These results are also in agreement with previous studies and imply that, compared to the C iv gas, the O vi line-emitting gas is closer to the accretion disc and is more strongly influenced by the accretion disc wind.

The radio emission is an important observable of quasars, but its relationship to Eigenvector 1 and the [O iii] λ5007 Baldwin Effect is not fully understood. We explore these issues based on a sample of 1800 quasars taken from the Sloan Digital Sky Survey Data Release 7. We employ a new approach of selecting subsamples in the plane of fundamental physical parameters of the black hole mass and Eddington ratio, so as to reduce variables and complexity in analyses. Based on these subsamples, we investigate the relationship between radio loudness R and Eigenvector 1 and find that radio loudness is correlated with [O iii] λ5007 emission, but has no clear relationship with optical Fe ii emission, which indicates that the radio power is probably not a driver of Eigenvector 1 but merely a secondary process. In addition, we also investigate the impact of radio loudness on the Baldwin Effect of [O iii] λ5007. We find that when the radio loudness is not strong (log R < 2), the Baldwin Effect of [O iii] λ5007 is clear, while in the samples of extreme radio loudness (log R ≥ 2), the Baldwin Effect of [O iii] λ5007 becomes weaker or even disappears. We suggest that both radio loudness and luminosity influence the relative strength of [O iii].

We present reverberation mapping measurements for the prominent ultraviolet broad emission lines of the active galactic nucleus Mrk817 using 165 spectra obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our ultraviolet observations are accompanied by X-ray, optical, and near-infrared observations as part of the AGN Space Telescope and Optical Reverberation Mapping Program 2 (AGN STORM 2). Using the cross-correlation lag analysis method, we find significant correlated variations in the continuum and emission-line light curves. We measure rest-frame delayed responses between the far-ultraviolet continuum at 1180 A and Ly$\alpha$ $\lambda1215$ A ($10.4_{-1.4}^{+1.6}$ days), N V $\lambda1240$ A ($15.5_{-4.8}^{+1.0}$days), SiIV + OIV] $\lambda1397$ A ($8.2_{-1.4}^{+1.4}$ days), CIV $\lambda1549$ A ($11.8_{-2.8}^{+3.0}$ days), and HeII $\lambda1640$ A ($9.0_{-1.9}^{+4.5}$ days) using segments of the emission-line profile that are unaffected by absorption and blending, which results in sampling different velocity ranges for each line. However, we find that the emission-line responses to continuum variations are more complex than a simple smoothed, shifted, and scaled version of the continuum light curve. We also measure velocity-resolved lags for the Ly$\alpha$, and CIV emission lines. The lag profile in the blue wing of Ly$\alpha$ is consistent with virial motion, with longer lags dominating at lower velocities, and shorter lags at higher velocities. The CIV lag profile shows the signature of a thick rotating disk, with the shortest lags in the wings, local peaks at $\pm$ 1500 $\rm km\,s^{-1}$, and a local minimum at line center. The other emission lines are dominated by broad absorption lines and blending with adjacent emission lines. These require detailed models, and will be presented in future work., Comment: Submitted to ApJ. 25 pages, 8 figures, and 6 tables

Full list of authors: Bao, Dong-Wei; Brotherton, Michael S.; Du, Pu; McLane, Jacob N.; Zastrocky, T. E.; Olson, Kianna A.; Fang, Feng-Na; Zhai, Shuo; Huang, Zheng-Peng; Wang, Kai; Zhao, Bi-Xuan; Li, Sha-Sha; Yang, Sen; Chen, Yong-Jie; Liu, Jun-Rong; Yao, Zhu-Heng; Peng, Yue-Chang; Guo, Wei-Jian; Songsheng, Yu-Yang; Li, Yan-Rong; Jiang, Bo-Wei; Kasper, David H.; Chick, William T.; Nguyen, My L.; Maithil, Jaya; Kobulnicky, H. A.; Dale, D. A.; Hand, Derek; Adelman, C.; Carter, Z.; Murphree, A. M.; Oeur, M.; Schonsberg, S.; Roth, T.; Winkler, Hartmut; Marziani, Paola; D'Onofrio, Mauro; Hu, Chen; Xiao, Ming; Xue, Suijian; Czerny, Bozena; Aceituno, Jesus; Ho, Luis C.; Bai, Jin-Ming; Wang, Jian-Min; MAHA Collaboration.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., In this third paper of the series reporting on the reverberation mapping campaign of active galactic nuclei with asymmetric Hβ emission-line profiles, we present results for 15 Palomar–Green quasars using spectra obtained between the end of 2016–2021 May. This campaign combines long time spans with relatively high cadence. For eight objects, both the time lags obtained from the entire light curves and the measurements from individual observing seasons are provided. Reverberation mapping of nine of our targets has been attempted for the first time, while the results for six others can be compared with previous campaigns. We measure the Hβ time lags over periods of years and estimate their black hole masses. The long duration of the campaign enables us to investigate their broad-line region (BLR) geometry and kinematics for different years by using velocity-resolved lags, which demonstrate signatures of diverse BLR geometry and kinematics. The BLR geometry and kinematics of individual objects are discussed. In this sample, the BLR kinematics of Keplerian/virialized motion and inflow is more common than that of outflow. © 2022. The Author(s). Published by the American Astronomical Society., We acknowledge the support by the National Science Foundation of China through grants NSFC-12022301, -11991051, -11991054, -11873048, -11833008, by National Key R&D Program of China (grants 2016YFA0400701), by grant No. QYZDJ-SSW-SLH007 from the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), by the Strategic Priority Research Program of CAS grant No.XDB23010400, and by the International Partnership Program of CAS, grant No.113111KYSB20200014. L.C.H. was supported by the National Science Foundation of China (11721303, 11991052) and the National Key R&D Program of China (2016YFA0400702). M.B. enjoyed support from the Chinese Academy of Sciences Presidents International Fellowship Initiative, grant No. 2018VMA0005. YRL acknowledges financial support from the National Natural Science Foundation of China through grant NSFC-11922304 and from the Youth Innovation Promotion Association CAS. H.C. acknowledges financial support from grant NSFC-12122305. We also acknowledge support from a University of Wyoming Science Initiative Faculty Innovation Seed grant. This work is supported by the National Science Foundation under REU grant AST 1852289. T.E.Z. acknowledges support from NSF grant 1005444I., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

It has been inferred from large unbiased samples that $10\%$-$15\%$ of all quasars are radio-loud (RL). Using the quasar catalog from the Sloan Digital Sky Survey, we show that the radio-loud fraction (RLF) for high broad line (HBL) quasars, containing H$\beta$ FWHM greater than $15,000$ km s$^{-1}$, is $\sim 57 \%$. While there is no significant difference between the RL and radio-quiet (RQ) populations in our sample in terms of their black hole mass, Eddington ratio, and covering fraction (CF), optical continuum luminosity of the RL quasars are higher. The similarity in the distribution of their CF indicates that our analysis is unbiased in terms of the viewing angle of the HBL RL and RQ quasars. Hence, we conclude that the accretion disc luminosity of the RL quasars in our HBL sample is higher, which indicates a connection between a brighter disc and a more prominent jet. By comparing them with the non-HBL H$\beta$ broad emission line quasars, we find that the HBL sources have the lowest Eddington ratios in addition to having a very high RLF. That is consistent with the theories of jet formation, in which jets are launched from low Eddington ratio accreting systems. We find that the [O III] narrow emission line is stronger in the RL compared to RQ quasars in our HBL sample, which is consistent with previous findings in the literature, and may be caused by the interaction of the narrow line gas with the jet., Comment: Accepted for publication in MNRAS

Determining black hole masses and accretion rates with better accuracy and precision is crucial for understanding quasars as a population. These are fundamental physical properties that underpin models of active galactic nuclei. A primary technique to measure the black hole mass employs the reverberation mapping of low-redshift quasars, which is then extended via the radius-luminosity relationship for the broad-line region to estimate masses based on single-epoch spectra. An updated radius-luminosity relationship incorporates the flux ratio of optical Fe ii to H$\beta$ ($\equiv \mathcal{R}_{\rm Fe}$) to correct for a bias in which more highly accreting systems have smaller line-emitting regions than previously realized. In this current work, we demonstrate and quantify the effect of using this Fe-corrected radius-luminosity relationship on mass estimation by employing archival data sets possessing rest-frame optical spectra over a wide range of redshifts. We find that failure to use a Fe-corrected radius predictor results in overestimated single-epoch black hole masses for the most highly accreting quasars. Their accretion rate measures ($L_{\rm Bol}/ L_{\rm Edd}$ and $\dot{\mathscr{M}}$), are similarly underestimated. The strongest Fe-emitting quasars belong to two classes: high-z quasars with rest-frame optical spectra, which given their extremely high luminosities, require high accretion rates, and their low-z analogs, which given their low black holes masses, must have high accretion rates to meet survey flux limits. These classes have mass corrections downward of about a factor of two, on average. These results strengthen the association of the dominant Eigenvector 1 parameter $\mathcal{R}_{\rm Fe}$ with the accretion process., Comment: Accepted by MNRAS, 16 pages. All figures are included in the source zip file (Download --> Other formats --> Source)

Current estimates of the normalized accretion rates of quasars (L/L_Edd), rely on measuring the velocity widths of broad optical-UV emission lines (e.g., H$\beta$ and Mg II $\lambda2800$). However, such lines tend to be weak or inaccessible in the most distant quasars, leading to increasing uncertainty in L/L_Edd estimates at $z > 6$. Utilizing a carefully selected sample of 53 radio-quiet quasars that have H$\beta$ and C IV $\lambda1549$ spectroscopy as well as {\sl Chandra} coverage, we searched for a robust accretion-rate indicator for quasars, particularly at the highest-accessible redshifts ($z \sim 6-7$). Our analysis explored relationships between the H$\beta$-based L/L_Edd, the equivalent width (EW) of C IV, and the optical-to-X-ray spectral slope (a_ox). Our results show that EW(C IV) is the strongest indicator of the H$\beta$-based L/L_Edd parameter, consistent with previous studies, although significant scatter persists particularly for sources with weak C IV lines. We do not find evidence for the a_ox parameter improving this relation, and we do not find a significant correlation between a_ox and H$\beta$-based L/L_Edd. This absence of an improved relationship may reveal a limitation in our sample. X-ray observations of additional luminous sources, found at $z \gtrsim 1$, may allow us to mitigate the biases inherent in our archival sample and test whether X-ray data could improve L/L_Edd estimates. Furthermore, deeper X-ray observations of our sources may provide accurate measurements of the hard-X-ray power-law photon index ($\Gamma$), which is considered an unbiased L/L_Edd indicator. Correlations between EW(C IV) and a_ox with $\Gamma$-based L/L_Edd may yield a more robust prediction of a quasar normalized accretion rate., Comment: 13 pages (aastex62), 4 figures. Accepted for publication in ApJ

We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-ray to the optical. The facilities included the telescopes of the CMO SAI MSU, the 2.3-m WIRO telescope, and the XRT and UVOT of Swift. We found that NGC 3516 brightened to a high state and could be classified as Sy1.5 during the late spring of 2020. We have measured time delays in the responses of the Balmer and He II 4686 lines to continuum variations. In the case of the best-characterized broad H-beta line, the delay to continuum variability is about 17 days in the blue wing and is clearly shorter, 9 days, in the red, which is suggestive of inflow. As the broad lines strengthened, the blue side came to dominate the Balmer lines, resulting in very asymmetric profiles with blueshifted peaks during this high state. During the outburst the X-ray flux reached its maximum on 1 April 2020 and it was the highest value ever observed for NGC 3516 by the Swift observatory. The X-ray hard photon index became softer, about 1.8 in the maximum on 21 Apr 2020 compared to the mean about 0.7 during earlier epochs before 2020. We have found that the UV and optical variations correlated well (with a small time delay of 1-2 days) with the X-ray until the beginning of April 2020, but later, until the end of Jun. 2020, these variations were not correlated. We suggest that this fact may be a consequence of partial obscuration by Compton-thick clouds crossing the line of sight., 18 pages, 18 figures, accepted by the MNRAS

We present a systematic X-ray and multiwavelength study of a sample of 47 active galactic nuclei (AGNs) with reverberation-mapping measurements. This sample includes 21 super-Eddington accreting AGNs and 26 sub-Eddington accreting AGNs. Using high-state observations with simultaneous X-ray and UV/optical measurements, we investigate whether super-Eddington accreting AGNs exhibit different accretion disk-corona connections compared to sub-Eddington accreting AGNs. We find tight correlations between the X-ray-to-UV/optical spectral slope parameter ($\alpha_{\rm OX}$) and the monochromatic luminosity at $2500~\r{A}$ ($L_{\rm 2500~\r{A}}$) for both the super- and sub-Eddington subsamples. The best-fit $\alpha_{\rm OX}-L_{\rm 2500~\r{A}}$ relations are consistent overall, indicating that super-Eddington accreting AGNs are not particularly X-ray weak in general compared to sub-Eddington accreting AGNs. We find dependences of $\alpha_{\rm OX}$ on both the Eddington ratio ($L_{\rm Bol}/L_{\rm Edd}$) and black hole mass ($M_{\rm BH}$) parameters for our full sample. A multi-variate linear regression analysis yields $\alpha_{\rm OX}=-0.13 {\rm log}(L_{\rm Bol}/L_{\rm Edd})-0.10 {\rm log}M_{\rm BH}-0.69$, with a scatter similar to that of the $\alpha_{\rm OX}-L_{\rm 2500~\r{A}}$ relation. The hard (rest-frame $>2\rm ~keV$) X-ray photon index ($\Gamma$) is strongly correlated with $L_{\rm Bol}/L_{\rm Edd}$ for the full sample and the super-Eddington subsample, but these two parameters are not significantly correlated for the sub-Eddington subsample. A fraction of super-Eddington accreting AGNs show strong X-ray variability, probably due to small-scale gas absorption, and we highlight the importance of employing high-state (intrinsic) X-ray radiation to study the accretion disk-corona connections in AGNs., Comment: 31 pages, 11 figures, accepted for publication in ApJ

We report velocity-delay maps for prominent broad emission lines, Ly_alpha, CIV, HeII and H_beta, in the spectrum of NGC5548. The emission-line responses inhabit the interior of a virial envelope. The velocity-delay maps reveal stratified ionization structure. The HeII response inside 5-10 light-days has a broad single-peaked velocity profile. The Ly_alpha, CIV, and H_beta responses peak inside 10 light-days, extend outside 20 light-days, and exhibit a velocity profile with two peaks separated by 5000 km/s in the 10 to 20 light-day delay range. The velocity-delay maps show that the M-shaped lag vs velocity structure found in previous cross-correlation analysis is the signature of a Keplerian disk with a well-defined outer edge at R=20 light-days. The outer wings of the M arise from the virial envelope, and the U-shaped interior of the M is the lower half of an ellipse in the velocity-delay plane. The far-side response is weaker than that from the near side, so that we see clearly the lower half, but only faintly the upper half, of the velocity--delay ellipse. The delay tau=(R/c)(1-sin(i))=5 light-days at line center is from the near edge of the inclined ring, giving the inclination i=45 deg. A black hole mass of M=7x10^7 Msun is consistent with the velocity-delay structure. A barber-pole pattern with stripes moving from red to blue across the CIV and possibly Ly_alpha line profiles suggests the presence of azimuthal structure rotating around the far side of the broad-line region and may be the signature of precession or orbital motion of structures in the inner disk. Further HST observations of NGC 5548 over a multi-year timespan but with a cadence of perhaps 10 days rather than 1 day could help to clarify the nature of this new AGN phenomenon., 19 pages, 9 figures, ApJ in press

We present spectroscopic measurements for 226 sources from the Gemini Near Infrared Spectrograph - Distant Quasar Survey (GNIRS-DQS). Being the largest uniform, homogeneous survey of its kind, it represents a flux-limited sample (mi . 19.0 mag, H . 16.5 mag) of Sloan Digital Sky Survey (SDSS) quasars at 1.5 . z . 3.5 with a monochromatic luminosity (λLλ) at 5100 ˚A in the range of 1044 − 1046 erg s−1 . A combination of the GNIRS and SDSS spectra covers principal quasar diagnostic features, chiefly the C iv λ1549, Mg ii λλ2798, 2803, Hβ λ4861, and [O iii] λλ4959, 5007 emission lines, in each source. The spectral inventory will be utilized primarily to develop prescriptions for obtaining more accurate and precise redshifts, black hole masses, and accretion rates for all quasars. Additionally, the measurements will facilitate an understanding of the dependence of rest-frame ultraviolet-optical spectral properties of quasars on redshift, luminosity, and Eddington ratio, and test whether the physical properties of the quasar central engine evolve over cosmic time., Facultad de Ciencias Astronómicas y Geofísicas, Instituto de Astrofísica de La Plata

From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution (SED) for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and HST/COS in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST/STIS data, in order to disentangle various spectral components of NGC 3227 and recover the underlying continuum. We find the observed NIR-optical-UV continuum is explained well by an accretion disk blackbody component (Tmax = 10 eV), which is internally reddened by E(B-V) = 0.45 with a Small Magellanic Cloud (SMC) extinction law. We derive the inner radius (12 Rg) and the accretion rate (0.1 solar mass per year) of the disk by modelling the thermal disk emission. The internal reddening in NGC 3227 is most likely associated with outflows from the dusty AGN torus. In addition, an unreddened continuum component is also evident, which likely arises from scattered radiation, associated with the extended narrow-line region (NLR) of NGC 3227. The extreme ultraviolet (EUV) continuum, and the 'soft X-ray excess', can be explained with a 'warm Comptonisation' component. The hard X-rays are consistent with a power-law and a neutral reflection component. The intrinsic bolometric luminosity of the AGN in NGC 3227 is about 2.2e+43 erg/s in 2019, corresponding to 3% Eddington luminosity. Our continuum modelling of the new triggered data of NGC 3227 requires the presence of a new obscuring gas with column density NH = 5e+22 cm^-2, partially covering the X-ray source (Cf = 0.6)., Accepted for publication in Astronomy & Astrophysics (A&A), 11 pages, 7 figures

Full list of authors: Kara, Erin; Mehdipour, Missagh; Kriss, Gerard A.; Cackett, Edward M.; Arav, Nahum; Barth, Aaron J.; Byun, Doyee; Brotherton, Michael S.; De Rosa, Gisella; Gelbord, Jonathan; Hernández Santisteban, Juan V.; Hu, Chen; Kaastra, Jelle; Landt, Hermine; Li, Yan-Rong; Miller, Jake A. ; Montano, John; Partington, Ethan; Aceituno, Jesús; Bai, Jin-Ming; Bao, Dongwei; Bentz, Misty C.; Brink, Thomas G.; Chelouche, Doron; Chen, Yong-Jie; Colmenero, Encarni Romero; Dalla Bontà, Elena; Dehghanian, Maryam; Du, Pu; Edelson, Rick; Ferland, Gary J.; Ferrarese, Laura; Fian, Carina; Filippenko, Alexei V.; Fischer, Travis; Goad, Michael R.; González Buitrago, Diego H.; Gorjian, Varoujan; Grier, Catherine J.; Guo, Wei-Jian; Hall, Patrick B.; Ho, Luis C.; Homayouni, Y.; Horne, Keith; Ilić, Dragana; Jiang, Bo-Wei; Joner, Michael D.; Kaspi, Shai; Kochanek, Christopher S.; Korista, Kirk T.; Kynoch, Daniel; Li, Sha-Sha; Liu, Jun-Rong; McHardy, Ian M.; McLane, Jacob N.; Mitchell, Jake A. J.; Netzer, Hagai; Olson, Kianna A.; Pogge, Richard W.; Popović, Luka Č.; Proga, Daniel; Storchi-Bergmann, Thaisa; Strasburger, Erika; Treu, Tommaso; Vestergaard, Marianne; Wang, Jian-Min; Ward, Martin J.; Waters, Tim; Williams, Peter R.; Yang, Sen; Yao, Zhu-Heng; Zastrocky, Theodora E.; Zhai, Shuo; Zu, Ying, We present the first results from the ongoing, intensive, multiwavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this active galactic nucleus was, in part, selected for its historically unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad, and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner broad-line region partially covers the central source. Despite the obscuration, we measure UV and optical continuum reverberation lags consistent with a centrally illuminated Shakura-Sunyaev thin accretion disk, and measure reverberation lags associated with the optical broad-line region, as expected. However, in the first 55 days of the campaign, when the obscuration was becoming most extreme, we observe a de-coupling of the UV continuum and the UV broad emission-line variability. The correlation recovered in the next 42 days of the campaign, as Mrk 817 entered a less obscured state. The short C iv and Lyα lags suggest that the accretion disk extends beyond the UV broad-line region. © 2021. The American Astronomical Society. All rights reserved., E.K. acknowledges support from NASA grant GO1-22116X. E.M.C. and J.A.M. gratefully acknowledge support from NSF grant AST-1909199. Research at UC Irvine was supported by NSF grant AST-1907290. H.L. acknowledges a Daphne Jackson Fellowship sponsored by the Science and Technology Facilities Council (STFC), UK. J.A.J.M. and M.J.W. acknowledge support from STFC grants ST/P000541/1 and ST/T000244/1. G.J.F. and M.D. acknowledge support by NSF (1816537, 1910687), NASA (ATP 17-ATP17-0141, 19-ATP19-0188), and STScI (HST-AR- 15018 and HST-GO-16196.003-A). Y.H. acknowledges support from NASA grants HST-GO-15650 and HST-GO-16-196. D.I. and L.Č. P. acknowledge funding provided by the Astronomical Observatory Belgrade (the contract 451-03-68/2020-14/200002), University of Belgrade—Faculty of Mathematics (the contract 451-03-9/2021-14/200104) through the grants by the Ministry of Education, Science, and Technological Development of the Republic of Serbia. D.I. acknowledges the support of the Alexander von Humboldt Foundation. M.V. gratefully acknowledges financial support from the Independent Research Fund Denmark via grant No. DFF 8021-00130. J.M.W. acknowledges financial support by the National Science Foundation of China (NSFC) through grants NSFC-11833008 and -11991054. P.D. acknowledges financial support from NSFC grants NSFC-12022301, -11873048, and -11991051, and from the Strategic Priority Research Program of the CAS (XDB23010400). C.H. acknowledges financial support from the grant NSFC-11773029 and from the National Key R&D Program of China (2016YFA0400701). Y.R.L. acknowledges financial support from the grant NSFC-11922304 and from the Youth Innovation Promotion Association CAS. J.V.H.S. and K.H. acknowledge support from STFC grant ST/R000824/1. P.B.H. is supported by NSERC. Support for A.V.F.'s group at U.C. Berkeley is provided by the TABASGO Foundation, the Christopher R. Redlich Fund, and the Miller Institute for Basic Research in Science (A.V.F. is a Senior Miller Fellow). M.C.B. gratefully acknowledges support from the NSF through grant AST-2009230. D.K. acknowledges support from the Czech Science Foundation project No. 19-05599Y. L.C.H. was supported by the National Key R&D Program of China (2016YFA0400702) and the National Science Foundation of China (11721303, 11991052). J.G. gratefully acknowledges support from NASA under the ADAP award 80NSSC17K0126., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

We report the results of reverberation mapping three bright Seyfert galaxies, Mrk 79, NGC 3227, and Mrk 841, from a campaign conducted from December 2016 to May 2017 with the Wyoming Infrared Observatory (WIRO) 2.3-meter telescope. All three of these targets have shown asymmetric broad H$\beta$ emission lines in the past, although their emission lines were relatively symmetric during our observations. We measured H\beta\ time lags for all three targets and estimated masses of their black holes -- for the first time in the case of Mrk 841. For Mrk 79 and NGC 3227, the data are of sufficient quality to resolve distinct time lags as a function of velocity and to compute two-dimensional velocity-delay maps. Mrk 79 shows smaller time lags for high-velocity gas but the distribution is not symmetric, and its complex velocity-delay map could result from the combination of both inflowing and outflowing H\beta\ emitting disks that may be part of a single larger structure. NGC 3227 shows the largest time lags for blueshifted gas and the two-dimensional velocity-delay map suggests a disk with some inflow. We compare our results with previous work and find evidence for different time lags despite similar luminosities, as well as evolving broad line region structures., Comment: 18 pages, 9 figures, 7 tables (table 3 is machine-readable and may be found in the source files as table3.txt), accepted by ApJ

We present geometric and dynamical modeling of the broad line region for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The dataset includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the H$\beta$, C IV, and Ly$\alpha$ broad emission lines. We find an extended disk-like H$\beta$ BLR with a mixture of near-circular and outflowing gas trajectories, while the C IV and Ly$\alpha$ BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C IV and Ly$\alpha$ emission arising at smaller radii than the H$\beta$ emission. Using the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of $\log_{10}(M_{\rm BH}/M_\odot) = 7.64^{+0.21}_{-0.18}$. We examine the effect of using the $V$ band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV-optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the $V$ band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the H$\beta$ results to similar models of data obtained in 2008 when the AGN was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remain unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole., Comment: 26 pages, 19 figures, 1 table, accepted for publication in ApJ

High-redshift quasars typically have their redshift determined from rest-frame ultraviolet (UV) emission lines. However, these lines, and more specifically the prominent C IV $��1549$ emission line, are typically blueshifted yielding highly uncertain redshift estimates compared to redshifts determined from rest-frame optical emission lines. We present near-infrared spectroscopy of 18 luminous quasars at $2.15 < z < 3.70$ that allows us to obtain reliable systemic redshifts for these sources. Together with near-infrared spectroscopy of an archival sample of 44 quasars with comparable luminosities and redshifts, we provide prescriptions for correcting UV-based redshifts. Our prescriptions reduce velocity offsets with respect to the systemic redshifts by $\sim140$ km s$^{-1}$ and reduce the uncertainty on the UV-based redshift by $\sim25\%$ with respect to the best method currently used for determining such values. We also find that the redshifts determined from the Sloan Digital Sky Survey Pipeline for our sources suffer from significant uncertainties, which cannot be easily mitigated. We discuss the potential of our prescriptions to improve UV-based redshift corrections given a much larger sample of high redshift quasars with near-infrared spectra., 13 pages (emulateapj), 5 figures, Accepted for publication in ApJ

Radio core dominance measurements, an indicator of jet orientation, sometimes rely on core flux density measurements from large-area surveys like Faint Images of the Radio Sky at Twenty cm (FIRST) that have an angular resolution of only 5''. Such low-resolution surveys often fail to resolve cores from the extended emission resulting in an erroneous measurement. We focus on investigating this resolution effect for a sample of 119 radio-loud quasars. We obtained continuum observations from NSF's Karl G. Jansky Very Large Array (VLA) at 10 GHz in A-array with a 0.2'' resolution. Our measurements show that at FIRST spatial resolution, core flux measurements are indeed systematically high even after considering the core-variability. For a handful of quasars, 10 GHz images reveal extended features, whereas the FIRST image shows a point source. We found that the resolution effect is more prominent for quasars with smaller angular sizes. We further computed two radio core dominance parameters R & R5100 for use in statistical orientation investigations with this sample. We also present the spectral energy distributions between 74 MHz and 1.4 GHz, which we used to measure the spectral index of the extended emission of these quasars. Our results empirically confirm that determination of radio core dominance requires high-spatial resolution data. We highlight the practical issues associated with the choice of frequency and resolution in the measurement of core and extended flux densities., Accepted by ApJ, 40 pages, 10 figures and 4 tables. All figures and machine readable tables are included in the source zip file (Download --> Other formats --> Source)

As one of the most interesting Seyfert 1 galaxies, PG 2130+099 has been the target of several reverberation mapping (RM) campaigns over the years. However, its measured broad Hβ line responses have been inconsistent, with time lags of ∼200 days, ∼25 days, and ∼10 days being reported for different epochs while its optical luminosity changed no more than 40%. To investigate this issue, we conducted a new RM-campaign with homogenous and high cadence (about ∼3 days) for two years during 2017-2019 to measure the kinematics and structure of the ionized gas. We successfully detected time lags of broad Hβ, He ii, He i, and Fe ii lines with respect to the varying 5100 Å continuum, revealing a stratified structure that is likely virialized with Keplerian kinematics in the first year of observations, but an inflow kinematics of the broad-line region from the second year. With a central black hole mass of 0.97+0.15 -0.18 × 107 Mo˙, PG 2130+099 has an accretion rate of 102.1 ± 0.5 LEdd c-2, where L Edd is the Eddington luminosity and c is speed of light, implying that it is a super-Eddington accretor and likely possesses a slim, rather than thin, accretion disk. The fast changes of the ionization structures of the three broad lines remain puzzling. © 2020. The American Astronomical Society. All rights reserved., The authors are grateful to an anonymous referee for very useful reports. The campaign made use of mainly the CAHA 2.2m, and jointly the Lijiang 2.4m and the Sutherland 1.9m telescopes, we acknowledge the support of the staff of these telescopes. This work is based on observations collected at the Centro Astronomico Hispanoen Andalucia (CAHA) at Calar Alto, operated jointly by the Andalusian Universities and the Instituto de Astrofisica de Andalucia (CSIC). Funding for the Lijiang 2.4m telescope has been provided by Chinese Academy of Sciences (CAS) and the People's Government of Yunnan Province. This research is supported by grant 2016YFA0400700 from the Ministry of Science and Technology of China, by NSFC grants NSFC-11773029, -11833008, -11991054, -11922304, -11873048, -11690024, and -11703077, by the CAS Key Research Program through KJZD-EW-M06, by the Key Research Program of Frontier Sciences, CAS, grant QYZDJ-SSWSLH007.

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC~5548 obtained with the Hubble Space Telescope during the 6-month reverberation-mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly$\alpha$ and C IV, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly$\alpha$ and C IV have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show delayed response to continuum variations corresponding to recombination in gas with a density of $\sim 10^5~\rm cm^{-3}$. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in $\sim\,2012$ corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state., Comment: 50 pages, 30 figures, uses aastex62.cls. Accepted for publication in ApJ, 07/06/2019. High-level products page in MAST will go live after 7/15/2019. Replaced Figure 4 on 7/12/2019 to be more red/green color-blind friendly

We analyze a set of optical-to-near-infrared long-slit nuclear spectra of 16 infrared-luminous spiral galaxies. All of the studied sources present H$_2$ emission, which reflects the star-forming nature of our sample, and they clearly display H I emission lines in the optical. Their continua contain many strong stellar absorption lines, with the most common features due to Ca I, Ca II, Fe I, Na I, Mg I, in addition to prominent absorption bands of TiO, VO, ZrO, CN and CO. We report a homogeneous set of equivalent width (EW) measurements for 45 indices, from optical to NIR species for the 16 star-forming galaxies as well as for 19 early type galaxies where we collected the data from the literature. This selected set of emission and absorption-feature measurements can be used to test predictions of the forthcoming generations of stellar population models. We find correlations among the different absorption features and propose here correlations between optical and NIR indices, as well as among different NIR indices, and compare them with model predictions. While for the optical absorption features the models consistently agree with the observations,the NIR indices are much harder to interpret. For early-type spirals the measurements agree roughly with the models, while for star-forming objects they fail to predict the strengths of these indices., accepted for publication in MNRAS

The spectrum of a quasar contains important information about its properties. Thus, it can be expected that two quasars with similar spectra will have similar properties, but just how similar has not before been quantified. Here we compare the ultraviolet spectra of a sample of 5553 quasars from Data Release 7 of the Sloan Digital Sky Survey, focusing on the $1350$ \AA \ $\leq \lambda \leq 2900$ \AA \ rest-frame region which contains prominent emission lines from \SiIV, O IV], \CIV, \CIII, and \MgII\ species. We use principal component analysis to determine the dominant components of spectral variation, as well as to quantitatively measure spectral similarity. As suggested by both the Baldwin effect and modified Baldwin effect, quasars with similar spectra have similar properties: bolometric luminosity, Eddington fraction, and black hole mass. The latter two quantities are calculated from the luminosity in conjunction with spectral features, and the variation between quasars with virtually identical spectra (which we call doppelg\"angers) is driven by the variance in the luminosity plus measurement uncertainties. In the doppelgangers the luminosity differences show 1$\sigma$ uncertainties of 57\% (or 0.63 magnitudes) and $\sim$70\% 1$\sigma$ uncertainties for mass and Eddington fraction. Much of the difference in luminosities may be attributable to time lags between the spectral lines and the continuum. Furthermore, we find that suggestions that the mostly highly accreting quasars should be better standard candles than other quasars are not bourne out for doppelgangers. Finally, we discuss the implications for using quasars as cosmological probes and the nature of the first two spectral principal components., Comment: 12 pages, 14 figures, accepted for publication by MNRAS

Authors: Hu, Chen; Li, Sha-Sha; Guo, Wei-Jian; Yang, Sen; Yang, Zi-Xu; Bao, Dong-Wei; Jiang, Bo-Wei; Du, Pu; Li, Yan-Rong; Xiao, Ming; Songsheng, Yu-Yang; Yu, Zhe; Bai, Jin-Ming; Ho, Luis C.; Bian, Wei-Hao; Brotherton, Michael S.; Yuan, Ye-Fei; Aceituno, Jesús; Winkler, Hartmut; Wang, Jian-Min; SEAMBH Collaboration, We report on the results of a new spectroscopic monitoring campaign of the quasar PG 0026+129 at the Calar Alto Observatory 2.2 m telescope from 2017 July to 2020 February. Significant variations in the fluxes of the continuum and broad emission lines, including Hβ and He ii, were observed in the first and third years, and clear time lags between them are measured. The broad Hβ line profile consists of two Gaussian components: an intermediate-width H with an FWHM of 1964 ± 18 and another very broad H with an FWHM of 7570 ± 83 . H has long time lags of ∼40-60 days in the rest frame, while H shows nearly zero time delay with respect to the optical continuum at 5100 Å. The velocity-resolved delays show consistent results: lags of ∼30-50 days at the core of the broad Hβ line and roughly zero lags at the wings. H has a redshift of ∼400 , which seems to be stable for nearly 30 yr by comparing with archived spectra, and may originate from an infall. The rms spectrum of H shows a double-peaked profile with brighter blue peak and extended red wing in the first year, which matches the signature of a thin disk. Both the double-peaked profile and the near-zero lag suggest that H comes from a region associated with the part of the accretion disk that emits the optical continuum. Adopting the FWHM (in the rms spectrum) and the time lag measured for the total Hβ line, and a virial factor of 1.5, we obtain a virial mass of for the central black hole in this quasar. © 2020. The American Astronomical Society. All rights reserved.., We acknowledge the support of the staff of the CAHA 2.2 m telescope. This work is based on observations collected at the Centro Astronomico Hispanoen Andalucia (CAHA) at Calar Alto, operated jointly by the Andalusian Universities and the Instituto de Astrofisica de Andalucia (CSIC). This research is supported by the National Key R&D Program of China (2016YFA0400701, 2016YFA0400702), by the National Science Foundation of China (11721303, 11773029, 11833008, 11873048, 11922304, 11973029, 11991051, 11991052, 11991054, 12003036, 12022301), by the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (CAS; QYZDJ-SSW-SLH007), by the CAS Key Research Program (KJZDEW-M06), and by the Strategic Priority Research Program of the CAS (XDB23000000, XDB23010400). J.A. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709).

We have started a long-term reverberation mapping project using the Wyoming Infrared Observatory 2.3 meter telescope titled "Monitoring AGNs with H\beta\ Asymmetry" (MAHA). The motivations of the project are to explore the geometry and kinematics of the gas responsible for complex H\beta\ emission-line profiles, ideally leading to an understanding of the structures and origins of the broad-line region (BLR). Furthermore, such a project provides the opportunity to search for evidence of close binary supermassive black holes. We describe MAHA and report initial results from our first campaign, from December 2016 to May 2017, highlighting velocity-resolved time lags for four AGNs with asymmetric H\beta\ lines. We find that 3C 120, Ark 120, and Mrk 6 display complex features different from the simple signatures expected for pure outflow, inflow, or a Keplerian disk. While three of the objects have been previously reverberation mapped, including velocity-resolved time lags in the cases of 3C 120 and Mrk 6, we report a time lag and corresponding black hole mass measurement for SBS 1518+593 for the first time. Furthermore, SBS 1518+593, the least asymmetric of the four, does show velocity-resolved time lags characteristic of a Keplerian disk or virialized motion more generally. Also, the velocity-resolved time lags of 3C 120 have significantly changed since previously observed, indicating an evolution of its BLR structure. Future analyses of the data for these objects and others in MAHA will explore the full diversity of H\beta\ lines and the physics of AGN BLRs., Comment: 19 pages, 6 figures, 7 tables, accepted for publication in The Astrophysical Journal

We present the first results from a reverberation-mapping campaign undertaken during the first half of 2012, with additional data on one AGN (NGC 3227) from a 2014 campaign. Our main goals are (1) to determine the black hole masses from continuum-Hbeta reverberation signatures, and (2) to look for velocity-dependent time delays that might be indicators of the gross kinematics of the broad-line region. We successfully measure Hbeta time delays and black hole masses for five AGNs, four of which have previous reverberation mass measurements. The values measured here are in agreement with earlier estimates, though there is some intrinsic scatter beyond the formal measurement errors. We observe velocity dependent Hbeta lags in each case, and find that the patterns have changed in the intervening five years for three AGNs that were also observed in 2007., Accepted for publication on ApJ; 32 pages, 16 figures, 10 tables

The masses of the black holes powering quasars represent a fundamental parameter of active galaxies. Estimates of quasar black hole masses using single-epoch spectra are quite uncertain, and require quantitative improvement. We recently identified a correction for C IV $\lambda$1549-based scaling relationships used to estimate quasar black hole masses that relies on the continuum-subtracted peak flux ratio of the ultraviolet emission-line blend Si IV + OIV] (the $\lambda$1400 feature) to that of C IV. This parameter correlates with the suite of associated quasar spectral properties collectively known as "Eigenvector 1" (EV1). Here we use a sample of 85 quasars with quasi-simultaneous optical-ultraviolet spectrophotometry to demonstrate how biases in the average EV1 properties can create systematic biases in C IV-based black hole mass scaling relationships. This effect results in nearly an order of magnitude moving from objects with small $ $, which have overestimated black hole masses, to objects with large $ $, which have underestimated values. We show that existing reverberation-mapped samples of quasars with ultraviolet spectra -- used to calibrate C IV-based scaling relationships -- have significant EV1 biases that result in predictions of black hole masses nearly 50\% too high for the average quasar. We offer corrections and suggestions to account for this bias.

In order to better understand the nature of post-starburst quasars (PSQs) in the context of galaxy evolution, we compare their properties to those of post-starburst galaxies and quasars from appropriately selected samples possessing similar redshift ($z \sim 0.3$), luminosity ($M_r \sim -$23), and data quality. We consider morphologies, spectral features, and derived physical properties of the stellar populations and central supermassive black hole. PSQs themselves come in two types: the more luminous AGNs with more luminous post-starburst stellar populations hosted by elliptical galaxies, some which are clearly merger products, and the less luminous systems existing within relatively undisturbed spiral galaxies and possessing signs of a more extended period of star formation. Post-starburst galaxies (PSQs) have elliptical and disturbed/post-merger morphologies similar to those of the more luminous PSQs, display similar spectral properties, but also can have younger stellar populations for a given starburst mass. Quasars at similar redshifts and luminosities around the Seyfert/quasar transition possess similar AGN characteristics, in terms of black hole mass and accretion rate, compared with those of PSQs, but do not appear to be hosted by galaxies with significant post-starburst populations. Recent studies of more luminous quasars find hosts consistent with those of our luminous PSQs, suggesting that these PSQs may be in transition between post-starburst galaxies and a more luminous quasar stage when the post-starburst stellar population remains dominant. The lower luminosity PSQs appear to differ from lower luminosity quasars (Seyfert galaxies) in terms of more significant star formation in their past., 13 pages, 9 figures, accepted for publication to MNRAS

Type 1 active galactic nuclei display broad emission lines, regarded as arising from photoionized gas moving in the gravitational potential of a supermassive black hole. The origin of this broad-line region gas is unresolved so far, however. Another component is the dusty torus beyond the broad-line region, likely an assembly of discrete clumps that can hide the region from some viewing angles and make them observationally appear as Type 2 objects. Here we report that these clumps moving within the dust sublimation radius, like the molecular cloud G2 discovered in the Galactic center, will be tidally disrupted by the hole, resulting in some gas becoming bound at smaller radii while other gas is ejected and returns to the torus. The clumps fulfill necessary conditions to be photoionized. Specific dynamical components of tidally disrupted clumps include spiral-in gas as inflow, circularized gas, and ejecta as outflow. We calculate various profiles of emission lines from these clouds, and find they generally agree with H$\beta$ profiles of Palomar-Green quasars. We find that asymmetry, shape and shift of the profiles strongly depend on [O III], luminosity, which we interpret as a proxy of dusty torus angles. Tidally disrupted clumps from the torus may represent the source of the broad-line region gas., Comment: appear in Nature Astronomy on October 9, 59 pages, 9 figures, 3 tables

We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multi-wavelength reverberation mapping campaign. The campaign spanned six months and achieved an almost daily cadence with observations from five ground-based telescopes. The H$\beta$ and He II $\lambda$4686 broad emission-line light curves lag that of the 5100 $\AA$ optical continuum by $4.17^{+0.36}_{-0.36}$ days and $0.79^{+0.35}_{-0.34}$ days, respectively. The H$\beta$ lag relative to the 1158 $\AA$ ultraviolet continuum light curve measured by the Hubble Space Telescope is roughly $\sim$50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is $\sim$50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for H$\beta$ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broad-line region dominated by Keplerian motion. The responses of both the H$\beta$ and He II $\lambda$4686 emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C IV, Ly $\alpha$, He II(+O III]), and Si IV(+O IV]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured H$\beta$ lag is a factor of five shorter than the expected value implied by the $R_\mathrm{BLR} - L_\mathrm{AGN}$ relation based on the past behavior of NGC 5548., Comment: 22 pages, 13 figures, accepted to ApJ

We present the results of a multiwavelength study of a sample of high-redshift radio-loud (RL) broad absorption line (BAL) quasars. This way, we extend to higher redshift previous studies on the radio properties and broad-band optical colours of these objects. We have selected a sample of 22 RL BAL quasars with 3.6 ≤ z ≤ 4.8 cross-correlating the FIRST radio survey with the Sloan Digital Sky Survey (SDSS). Flux densities between 1.25 and 9.5 GHz have been collected with the Jansky Very Large Array and Effelsberg-100 m telescopes for 15 BAL and 14 non-BAL quasars used as a comparison sample. We determine the synchrotron peak frequency, constraining their age. A large number of gigahertz peaked spectrum and high-frequency peakers sources have been found in both samples (80 per cent for BAL and 71 per cent for non-BAL quasars), not suggesting a younger age for BAL quasars. The spectral index distribution provides information about the orientation of these sources, and we find statistically similar distributions for the BAL and non-BAL quasars in contrast to work done on lower redshift samples. Our sample may be too small to convincingly find the same effect, or might represent a real evolutionary effect based on the large fraction of young sources. We also study the properties of broad-band colours in both optical (SDSS) and near- and mid-infrared (UK Infrared Telescope Deep Sky Survey and Wide-field Infrared Survey Explorer –WISE) bands, finding that also at high-redshift BAL quasars tend to be optically redder than non-BAL quasars. However, these differences are no more evident at longer wavelength, when comparing colours of the two samples by mean of the WISE survey., This work has been funded by the Spanish Ministerio de Economía y Competitividad (MINECO) under projects AYA2011-29517-C03-02 and AYA2014-58861-C3-2-P. The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreement no. 283393 (RadioNet3).

Quasar redshifts require the best possible precision and accuracy for a number of applications, such as setting the velocity scale for outflows as well as measuring small-scale quasar-quasar clustering. The most reliable redshift standard in luminous quasars is arguably the narrow [OIII] $\lambda\lambda$4959,5007 emission line doublet in the rest-frame optical. We use previously published [OIII] redshifts obtained using near-infrared spectra in a sample of 45 high-redshift (z > 2.2) quasars to evaluate redshift measurement techniques based on rest-frame ultraviolet spectra. At redshifts above z = 2.2 the MgII $\lambda$2798 emission line is not available in observed-frame optical spectra, and the most prominent unblended and unabsorbed spectral feature available is usually CIV $\lambda$1549. Peak and centroid measurements of the CIV profile are often blueshifted relative to the rest-frame of the quasar, which can significantly bias redshift determinations. We show that redshift determinations for these high-redshift quasars are significantly correlated with the emission-line properties of CIV (i.e., the equivalent width, or EW, and the full width at half maximum, or FWHM) as well as the luminosity, which we take from the Sloan Digital Sky Survey Data Release 7. We demonstrate that empirical corrections based on multiple regression analyses yield significant improvements in both the precision and accuracy of the redshifts of the most distant quasars and are required to establish consistency with redshifts determined in more local quasars.

We have used optical Integral Field Spectroscopy in order to map the star formation history of the inner kiloparsec of the Post-Starburst Quasar (PSQ) J0330--0532 and to map its gas and stellar kinematics as well as the gas excitation. PSQs are hypothesized to represent a stage in the evolution of galaxies in which the star formation has been recently quenched due to the feedback of the nuclear activity, as suggested by the presence of the post-starburst population at the nucleus. We have found that the old stellar population (age $\ge$ 2.5 Gyr) dominates the flux at 5100 \AA\ in the inner 0.26 kpc, while both the post-starburst (100 Myr $\le$ age $, Comment: 16 pages, 11 figures. arXiv admin note: text overlap with arXiv:1210.1208

Studying the relationships among quasar spectral features is essential to unveil the origins of the emission lines and the quasars’ physical processes. Principal component analysis (PCA) is a powerful tool to investigate correlations between variables. Here, we present the results of PCA on the spectra of low-redshift SDSS quasars. The rest-frame wavelength range studied is 4000 – 5500 Å, involving some typical features of quasar spectra, such as Hβ, [O iii] and Fe ii emission lines. The first principal component is the anti-correlation between [O iii] and Fe ii, the well-known eigenvector one (EV1). The next six principal components also show clear (anti-)correlations between line strengths and/or velocity widths of various features, which agree well with measured spectral properties. By comparing the weights of these principal components with other quasar properties, we can identify their underlying drivers. We find that the second principal component represents spectral slope, and can quantify quasar host fraction, intrinsic slope and reddening well. The third component exhibits the velocity width variation of Hβ, and may be a proxy for orientation. In addition, we calculate the fractional-contribution spectra to investigate which components dominate the variance at individual wavelength ranges. Our results also indicate that the optical Fe ii emission may have distinct origins.

We analyse a set of optical-to-near-infrared long-slit nuclear spectra of 16 infrared-luminous spiral galaxies. All of the studied sources present H2 emission, which reflects the star-forming nature of our sample, and they clearly display H I emission lines in the optical. Their continua contain many strong stellar absorption lines, with the most common features due to Ca I, Ca II, Fe I, Na I, Mg I, in addition to prominent absorption bands of TiO, VO, ZrO, CN, and CO. We report a homogeneous set of equivalent width (EW) measurements for 45 indices, from optical to NIR species for the 16 star-forming galaxies as well as for 19 early-type galaxies where we collected the data from the literature. This selected set of emission and absorption-feature measurements can be used to test predictions of the forthcoming generations of stellar population models. We find correlations among the different absorption features and propose here correlations between optical and NIR indices, as well as among different NIR indices, and compare them with model predictions. Although for the optical absorption features the models consistently agree with the observations, the NIR indices are much harder to interpret. For early-type spirals the measurements agree roughly with the models, while for star-forming objects they fail to predict the strengths of these indices.

We report the discovery of extreme X-ray variability in a type 1 quasar: SDSS J$075101.42+291419.1$. It has a black hole mass of $1.6\times 10^7~\rm M_\odot$ measured from reverberation mapping (RM), and the black hole is accreting with a super-Eddington accretion rate. Its XMM-Newton observation in 2015 May reveals a flux drop by a factor of $\sim 22$ with respect to the Swift observation in 2013 May when it showed a typical level of X-ray emission relative to its UV/optical emission. The lack of correlated UV variability results in a steep X-ray-to-optical power-law slope ($\alpha_{\rm OX}$) of -1.97 in the low X-ray flux state, corresponding to an X-ray weakness factor of 36.2 at rest-frame 2 keV relative to its UV/optical luminosity. The mild UV/optical continuum and emission-line variability also suggest that the accretion rate did not change significantly. A single power-law model modified by Galactic absorption describes well the $0.3-10$ keV spectra of the X-ray observations in general. The spectral fitting reveals steep spectral shapes with $\Gamma\approx3$. We search for active galactic nuclei (AGNs) with such extreme X-ray variability in the literature and find that most of them are narrow-line Seyfert 1 galaxies and quasars with high accretion rates. The fraction of extremely X-ray variable objects among super-Eddington accreting AGNs is estimated to be $\approx 15-24\%$. We discuss two possible scenarios, disk reflection and partial covering absorption, to explain the extreme X-ray variability of SDSS J$075101.42+291419.1$. We propose a possible origin for the partial covering absorber, which is the thick inner accretion disk and its associated outflow in AGNs with high accretion rates., Comment: 15 pages, 9 figures, accepted for publication in ApJ

We study the kinematics and excitation mechanisms of H 2 and [Fe ii] lines in a sample of 67 emission-line galaxies with Infrared Telescope Facility SpeX near-infrared (0.8–2.4 μm) spectroscopy together with new photoionization models. H 2 emission lines are systematically narrower than narrow-line region lines, suggesting that the two are, very likely, kinematically disconnected. The new models and emission-line ratios show that the thermal excitation plays an important role not only in active galactic nuclei but also in star-forming galaxies. The importance of the thermal excitation in star-forming galaxies may be associated with the presence of supernova remnants close to the region emitting H 2 lines. This hypothesis is further supported by the similarity between vibrational and rotational temperatures of H 2 . We confirm that the diagram involving the line ratios H 2 2.121 μm/Brγ and [Fe ii] 1.257 μm/Paβ is an efficient tool for separating emission-line objects according to their dominant types of activities. We suggest new limits to the line ratios in order to discriminate between the different types of nuclear activities.