We present measurements of the spectral properties for a total of 526,265 quasars, out of which 63% have a continuum signal-to-noise ratio > 3 pixel−1, selected from the fourteenth data release of ...the Sloan Digital Sky Survey (SDSS-DR14) quasar catalog. We performed a careful and homogeneous analysis of the SDSS spectra of these sources to estimate the continuum and line properties of several emission lines such as H , Hβ, Hγ, Mg ii, C iii, C iv, and Ly . From the derived emission line parameters, we estimated single-epoch virial black hole masses (MBH) for the sample using Hβ, Mg ii, and C iv emission lines. The sample covers a wide range in bolometric luminosity ( erg s−1) between 44.4 and 47.3 and between 7.1 and 9.9 M . Using the ratio of Lbol to the Eddington luminosity as a measure of the accretion rate, the logarithm of the accretion rate is found to be in the range between −2.06 and 0.43. We performed several correlation analyses between different emission line parameters and found them to match the correlation known earlier using smaller samples. We note that strong Fe ii sources with a large Balmer line width and highly accreting sources with large MBH are rare in our sample. We make an extended and complete catalog available online that contains various spectral properties of 526,265 quasars derived in this work along with other properties culled from the SDSS-DR14 quasar catalog.
ABSTRACT Supermassive black holes launching plasma jets at close to the speed of light, producing gamma-rays, have ubiquitously been found to be hosted by massive elliptical galaxies. Since ...elliptical galaxies are generally believed to be built through galaxy mergers, active galactic nuclei (AGN) launching relativistic jets are associated with the latest stages of galaxy evolution. We have discovered a pseudobulge morphology in the host galaxy of the gamma-ray AGN PKS 2004-447. This is the first gamma-ray emitter radio-loud AGN found to have been launched from a system where both the black hole and host galaxy have been actively growing via secular processes. This is evidence of an alternative black hole-galaxy co-evolutionary path to develop powerful relativistic jets, which is not merger driven.
Abstract The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift ( z < 0.8) because their definition requires the presence of the H β emission line, which is ...redshifted out of the spectral coverage of major ground-based spectroscopic surveys at z > 0.8. We studied the correlation between the properties of H β and Mg ii lines of a large sample of SDSS DR14 quasars to find high- z NLS1 candidates. Based on the strong correlation of FWHM(Mg II ) = (0.880 ± 0.005) × FWHM(H β ) + (0.438 ± 0.018), we present a sample of high- z NLS1 candidates having FWHM of Mg ii < 2000 km s −1 . The high- z sample contains 2684 NLS1s with redshift z = 0.8–2.5 with a median logarithmic bolometric luminosity of 46.16 ± 0.42 erg s −1 , logarithmic black hole mass of 8.01 ± 0.35 M ⊙ , and logarithmic Eddington ratio of 0.02 ± 0.27. The fraction of radio-detected high- z NLS1s is similar to that of the low- z NLS1s and SDSS DR14 quasars at a similar redshift range, and their radio luminosity is found to be strongly correlated with their black hole mass.
Abstract
We explore the properties of galaxies in the proximity (within a ∼2 Mpc radius sphere) of Type I quasars at 0.1 <
z
<0.35, to check whether and how an active galaxy influences the properties ...of its neighbors. We further compare these with the properties of neighbors around inactive galaxies of the same mass and redshift within the same volume of space, using the Galaxy and Mass Assembly spectroscopic survey. Our observations reveal no significant difference in properties such as the number of neighbors, morphologies, stellar mass, star formation rates, and star formation history between the neighbors of quasars and those of the comparison sample. This implies that quasar activity in a host galaxy does not significantly affect its neighbors (e.g., via interactions with the jets). Our results suggest that quasar host galaxies do not strongly differ from the average galaxy within the specified mass and redshift range. Additionally, the implication of the relatively minor importance of the environmental effect on and from quasars is that nuclear activity is more likely triggered by internal and secular processes.
We present near-IR spectroscopy of 22 luminous low-ionization broad absorption line quasars (LoBAL QSOs) at redshift , with 12 objects at z ∼ 1.5 and 10 at z ∼ 2.3. The spectra cover the rest-frame H ...and Hβ line regions, allowing us to obtain robust black hole mass estimates based on the broad H line. We use these data, augmented by a lower-redshift sample from the Sloan Digital Sky Survey, to test the proposed youth scenario for LoBALs, which suggests that LoBALs constitute an early short-lived evolutionary stage of quasar activity, by probing for any difference in their masses, Eddington ratios, or rest-frame optical spectroscopic properties compared to normal quasars. In addition, we construct the UV to mid-IR spectral energy distributions (SEDs) for the LoBAL sample and a matched non-BAL quasar sample. We do not find any statistically significant difference between LoBAL QSOs and non-BAL QSOs in their black hole mass or Eddington ratio distributions. The mean UV to mid-IR SED of the LoBAL QSOs is consistent with non-BAL QSOs, apart from their stronger reddening. At there is no clear difference in their optical emission line properties. We do not see particularly weak O iii or strong Fe ii emission. The LoBAL QSOs do not show a stronger prevalence of ionized gas outflows as traced by the O iii line, compared to normal QSOs of similar luminosity. We conclude that the optical-MIR properties of LoBAL QSOs are consistent with the general quasar population and do not support them to constitute a special phase of active galactic nucleus evolution.
Quasars are useful tracers of the cosmological evolution of the black hole mass-galaxy relation. We compare the expectations of semi-analytical models (SAMs) of galaxy evolution to the largest ...available data sets of quasar host galaxies out to z≃ 3.
Observed quasar hosts are consistent with no evolution from the local M
BH−L
host relation and suggest a significant increase of the mass ratio
from z= 0 to 3. Taken at face value, this is totally at odds with the predictions of SAMs, where the intrinsic Γ shows little evolution and quasar host galaxies at high redshift are systematically overluminous (and/or have an undermassive BH). However, since quasars preferentially trace very massive black holes (109-1010 M⊙) at the steep end of the luminosity and mass function, the ensuing selection biases can reconcile the present SAMs with the observations. A proper interpretation of quasar host data thus requires the global approach of SAMs so as to account for statistical biases.
We present near-infrared imaging obtained with ESO VLT/ISAAC of a sample of 16 low luminosity radio-quiet quasars (RQQs) at the epoch around the peak of the quasar activity (2 < z < 3), aimed at ...investigating their host galaxies. For 11 quasars, we are able to detect the host galaxies and derive their properties, while for the other 5 quasars, upper limits to the host luminosity are estimated. The luminosities of the host galaxies of RQQs at high redshift are in the range of those of massive inactive elliptical galaxies. This work complements our previous systematic study of quasar hosts aimed to trace the cosmological luminosity evolution of the host galaxies up to z ~ 2 and extends our pilot study of a few luminous quasars at z > 2. The luminosity trend with a cosmic epoch resembles that observed for massive inactive galaxies, suggesting a similar star formation history. In particular, both quasar host galaxies and massive inactive galaxies appear mostly assembled already at the peak age of the quasar activity. This result is of key importance for testing the models of joint formation and evolution of galaxies and their active nuclei.
It is important to understand the interplay between nuclear star formation and nuclear activity when studying the evolution of gas-rich galaxy mergers. We present here new spatially resolved L-band ...integral field unit observations of the inner kpc of the luminous infrared galaxy NGC 1614. A broad ring of 3.3-μm polycyclic aromatic hydrocarbon (PAH) emission is found at a distance of approximately 200 pc from the core. This ring overlaps with a previously established star-forming ring detected with Paα and radio continuum observations, but peaks outside it, especially if determined using the PAH equivalent width. Using the characteristics of the PAH emission and the ionized gas emission, we argue that NGC 1614 features an outward propagating ring of star formation, where the equivalent width of the PAH emission localizes the regions where the current star formation is just expanding into the molecular gas outward of the nucleus. The core itself shows a highly luminous, slightly resolved (at ∼80 pc) L-band continuum source. We find no evidence of active galactic nucleus (AGN) activity and rule out the presence of an obscured AGN using L-band diagnostics. Furthermore, we detect the likely companion galaxy from archival Hubble Space Telescope/Advanced Camera for Surveys (ACS) imaging. The star formation and dynamical characteristics of the system are consistent with a relatively major merger just after its second passage. An outstanding question is how a gas-rich advanced merger such as this one, with strong luminous infrared galaxies level nuclear starburst and major-merger-like tidal features, has not yet developed an active nucleus.
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