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Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman α forest. We present a catalogue of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are 243 km s−1 smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study.

The correlation between the broad line region radius and continuum luminosity (R-L relation) of active galactic nuclei (AGNs) is critical for single-epoch mass estimates of supermassive black holes (SMBHs). At z ∼ 1-2, where AGN activity peaks, the R-L relation is constrained by the reverberation mapping (RM) lags of the Mg II line. We present 25 Mg II lags from the Australian Dark Energy Survey RM project based on 6 yr of monitoring. We define quantitative criteria to select good lag measurements and verify their reliability with simulations based on both the damped random walk stochastic model and the rescaled, resampled versions of the observed light curves of local, well-measured AGN. Our sample significantly increases the number of Mg II lags and extends the R-L relation to higher redshifts and luminosities. The relative iron line strength RFe has little impact on the R-L relation. The best-fitting Mg II R-L relation has a slope α = 0.39 ± 0.08 with an intrinsic scatter σrl = 0.15+−000203. The slope is consistent with previous measurements and shallower than the H β R-L relation. The intrinsic scatter of the new R-L relation is substantially smaller than previous studies and comparable to the intrinsic scatter of the H β R-L relation. Our new R-L relation will enable more precise single-epoch mass estimates and SMBH demographic studies at cosmic noon.

Reverberation mapping measurements have been used to constrain the relationship between the size of the broad-line region and luminosity of active galactic nuclei (AGN). This R-L relation is used to estimate single-epoch virial black hole masses, and has been proposed to use to standardize AGN to determine cosmological distances. We present reverberation measurements made with Hβ from the 6-yr Australian Dark Energy Survey (OzDES) Reverberation Mapping Program. We successfully recover reverberation lags for eight AGN at 0.12 < z < 0.71, probing higher redshifts than the bulk of Hβ measurements made to date. Our fit to the R-L relation has a slope of α = 0.41 ± 0.03 and an intrinsic scatter of σ = 0.23 ± 0.02 dex. The results from our multi-object spectroscopic survey are consistent with previous measurements made by dedicated source-by-source campaigns, and with the observed dependence on accretion rate. Future surveys, including LSST, TiDES, and SDSS-V, which will be revisiting some of our observed fields, will be able to build on the results of our first-generation multi-object reverberation mapping survey.

ABSTRACT: We present the discovery that ATLAS18mlw was a tidal disruption event (TDE) in the galaxy WISEA J073544.83+663717.3, at a luminosity distance of 334 Mpc. Initially discovered by the Asteroid Terrestrial Impact Last Alert System (ATLAS) on 2018 March 17.3, the TDE nature of the transient was uncovered only recently with the re-reduction of a SuperNova Integral Field Spectrograph (SNIFS) spectrum. This spectrum, taken by the Spectral Classification of Astronomical Transients (SCAT) survey, shows a strong blue continuum and a broad H α emission line. Here, we present roughly 6 yr of optical survey photometry beginning before the TDE to constrain active galactic nucleus activity, optical spectroscopy of the transient, and a detailed study of the host galaxy properties through analysis of archival photometry and a host spectrum. ATLAS18mlw was detected in ground-based light curves for roughly 2 months. From a blackbody fit to the transient spectrum and bolometric correction of the optical light curve, we conclude that ATLAS18mlw is best explained by a low-luminosity TDE with a peak luminosity of log(L [erg s−1]) = 43.5 ± 0.2. The TDE classification is further supported by the quiescent Balmer strong nature of the host galaxy. We also calculated the TDE decline rate from the bolometric light curve and find ΔL40 = −0.7 ± 0.2 dex, making ATLAS18mlw a member of the growing class of ‘faint and fast’ TDEs with low peak luminosities and fast decline rates.

We present the results from an analysis of deep Herschel far-infrared (far-IR) observations of the edge-on disc galaxy NGC 3079. The point spread function-cleaned Photodetector Array Camera and Spectrometer (PACS) images at 100 and 160 μm display a 25 × 25 kpc2 X-shape structure centred on the nucleus that is similar in extent and orientation to that seen in H α, X-rays, and the far-ultraviolet. One of the dusty filaments making up this structure is detected in the Spectral and Photometric Imaging Receiver 250 μm map out to ∼25 kpc from the nucleus. The match between the far-IR filaments and those detected at other wavelengths suggests that the dusty material has been lifted out of the disc by the same large-scale galactic wind that has produced the other structures in this object. A closer look at the central 10 × 10 kpc2 region provides additional support for this scenario. The dust temperatures traced by the 100-160 μm flux ratios in this region are enhanced within a biconical region centred on the active galactic nucleus, aligned along the minor axis of the galaxy, and coincident with the well-known double-lobed cm-wave radio structure and H α-X-ray nuclear superbubbles. PACS imaging spectroscopy of the inner 6 kpc region reveals broad [C ii] 158 μm emission line profiles and OH 79 μm absorption features along the minor axis of the galaxy with widths well in excess of those expected from beam smearing of the disc rotational motion. This provides compelling evidence that the cool material traced by the [C ii] and OH features directly interacts with the nuclear ionized and relativistic outflows traced by the H α, X-ray, and radio emission.

Periodically variable quasars have been suggested as close binary supermassive black holes. We present a systematic search for periodic light curves in 625 spectroscopically confirmed quasars with a median redshift of 1.8 in a 4.6 deg2 overlapping region of the Dark Energy Survey Supernova (DES-SN) fields and the Sloan Digital Sky Survey Stripe 82 (SDSS-S82). Our sample has a unique 20-yr long multicolour (griz) light curve enabled by combining DES-SN Y6 observations with archival SDSS-S82 data. The deep imaging allows us to search for periodic light curves in less luminous quasars (down to r∼23.5 mag) powered by less massive black holes (with masses ≳ 108.5M⊙) at high redshift for the first time. We find five candidates with significant (at >99.74 per cent single-frequency significance in at least two bands with a global p-value of ∼7 × 10-4 -3 × 10-3 accounting for the look-elsewhere effect) periodicity with observed periods of ∼3-5 yr (i.e. 1-2 yr in rest frame) having ∼4-6 cycles spanned by the observations. If all five candidates are periodically variable quasars, this translates into a detection rate of ∼0.8+0.5-0.3 per cent or ∼1.1+0.7-0.5 quasar per deg2. Our detection rate is 4-80 times larger than those found by previous searches using shallower surveys over larger areas. This discrepancy is likely caused by differences in the quasar populations probed and the survey data qualities. We discuss implications on the future direct detection of low-frequency gravitational waves. Continued photometric monitoring will further assess the robustness and characteristics of these candidate periodic quasars to determine their physical origins.

We show that individual (single-epoch) spectra of active galactic nuclei (AGNs) can constrain some of the geometry and dynamics of the AGN broad line region. Studies of the cosmic influence of supermassive black holes are limited by the current large uncertainties in the determination of black hole masses. One dominant limitation is the unknown geometry, dynamics, and line-of-sight inclination of the broad line region, used to probe the central black hole mass. Recent progress has been made to constrain the spatial and kinematic structure of the broad line region using dynamical modelling of AGN monitoring data and an underlying physical model for the broad line region. In this work we test the ability of a modified version of this dynamical modelling code to constrain the broad line region structure using single-epoch spectra.We test our modelling code on single-epoch spectra of nearby Arp 151 by comparing our results with those obtained with monitoring data of this same object. We find that a significant fraction of the broad line region parameters can indeed be adequately constrained, with uncertainties that are comparable to, or at most a factor of approximately a few higher than those obtained from modelling of monitoring data. Considering the wealth of available single-epoch spectroscopic observations, this method is promising for establishing the overall AGN population trends in the geometry and dynamics of the broad line region. This method can be applied to spectra of AGNs at low and high redshift making it valuable for studies of cosmological black hole and AGN evolution.

ABSTRACT We observed the Brackett α emission line (4.05 μm) within the nuclear starburst of NGC 253 to measure the kinematics of ionized gas, and distinguish motions driven by star formation feedback from gravitational motions induced by the central mass structure. Using NIRSPEC on Keck II, we obtained 30 spectra through a $0^{\prime \prime }_{.}5$ slit stepped across the central ∼5 arcsec × 25 arcsec (85 × 425 pc) region to produce a spectral cube. The Br α emission resolves into four nuclear sources: S1 at the infrared core (IRC), N1 at the radio core, and the fainter sources N2 and N3 in the northeast. The line profile is characterized by a primary component with Δvprimary ∼90–130 $\rm km\, s^{-1}$ (full width at half-maximum) on top of a broad blue 2wing with Δvbroad ∼300–350 $\rm km\, s^{-1}$, and an additional redshifted narrow component in the west. The velocity field generated from our cube reveals several distinct patterns. A mean NE–SW velocity gradient of +10 $\rm km\, s^{-1}$ arcsec−1 along the major axis traces the solid-body rotation curve of the nuclear disc. At the radio core, isovelocity contours become S-shaped, indicating the presence of secondary nuclear bar of total extent ∼5 arcsec (90 pc). The symmetry of the bar places the galactic centre, and potential supermassive black hole, near the radio peak rather than the IRC. A third kinematic substructure is formed by blueshifted gas near the IRC. This feature likely traces a ∼100–250 $\rm km\, s^{-1}$ starburst-driven outflow, potentially linking the IRC to the galactic wind observed on kpc scales.

We show that individual (single-epoch) spectra of active galactic nuclei (AGNs) can constrain some of the geometry and dynamics of the AGN broad line region. Studies of the cosmic influence of supermassive black holes are limited by the current large uncertainties in the determination of black hole masses. One dominant limitation is the unknown geometry, dynamics, and line-of-sight inclination of the broad line region, used to probe the central black hole mass. Recent progress has been made to constrain the spatial and kinematic structure of the broad line region using dynamical modelling of AGN monitoring data and an underlying physical model for the broad line region. In this work we test the ability of a modified version of this dynamical modelling code to constrain the broad line region structure using single-epoch spectra.We test our modelling code on single-epoch spectra of nearby Arp 151 by comparing our results with those obtained with monitoring data of this same object. We find that a significant fraction of the broad line region parameters can indeed be adequately constrained, with uncertainties that are comparable to, or at most a factor of approximately a few higher than those obtained from modelling of monitoring data. Considering the wealth of available single-epoch spectroscopic observations, this method is promising for establishing the overall AGN population trends in the geometry and dynamics of the broad line region. This method can be applied to spectra of AGNs at low and high redshift making it valuable for studies of cosmological black hole and AGN evolution.

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 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 and C iv have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show a delayed response to continuum variations corresponding to recombination in gas with a density of ∼105 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 ∼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.

We present ∼0.″10 resolution Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) imaging of the arcsecond-scale (r ≈ 150 pc) dusty molecular disk in the giant elliptical galaxy NGC 3258. The data provide unprecedented resolution of the cold gas disk kinematics within the dynamical sphere of influence of a supermassive black hole (BH), revealing a quasi-Keplerian central increase in projected rotation speed rising from 280 km s-1 at the disk's outer edge to >400 km s-1 near the disk center. We construct dynamical models for the rotating disk and fit beam-smeared model CO line profiles directly to the ALMA data cube. Our models incorporate both flat and tilted-ring disks that provide a better fit of the mildly warped structure in NGC 3258. We show that the exceptional angular resolution of the ALMA data makes it possible to infer the host galaxy's mass profile within r = 150 pc solely from the ALMA CO kinematics, without relying on optical or near-infrared imaging data to determine the stellar mass profile. Our model therefore circumvents any uncertainty in the BH mass that would result from the substantial dust extinction in the galaxy's central region. The best model fit yields , with a statistical model-fitting uncertainty of just 0.18% and systematic uncertainties of 0.62% from various aspects of the model construction and 12% from uncertainty in the distance to NGC 3258. This observation demonstrates the full potential of ALMA for carrying out highly precise measurements of in early-type galaxies containing circumnuclear gas disks.

We present the discovery of PS18kh, a tidal disruption event discovered at the center of SDSS J075654.53+341543.6 (d ≃ 322 Mpc) by the Pan-STARRS Survey for Transients. Our data set includes pre-discovery survey data from Pan-STARRS, the All-sky Automated Survey for Supernovae, and the Asteroid Terrestrial-impact Last Alert System as well as high-cadence, multiwavelength follow-up data from ground-based telescopes and Swift, spanning from 56 days before peak light until 75 days after. The optical/UV emission from PS18kh is well-fit as a blackbody with temperatures ranging from T ≃ 12,000 K to T ≃ 25,000 K and it peaked at a luminosity of L ≃ 8.8 × 1043 erg s-1. PS18kh radiated E = (3.45 ± 0.22) × 1050 erg over the period of observation, with (1.42 ± 0.20) × 1050 erg being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked Hα emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the Hα line and its evolution. We find that at early times the high accretion rate leads the disk to emit a wind which modifies the shape of the line profile and makes it bell-shaped. At late times, the wind becomes optically thin, allowing the non-axisymmetric perturbations to show up in the line profile. The line-emitting portion of the disk extends from r in ∼ 60r g to an outer radius of r out ∼ 1400r g and the perturbations can be represented either as an eccentricity in the outer rings of the disk or as a spiral arm in the inner disk.

We present the discovery of PS18kh, a tidal disruption event discovered at the center of SDSS J075654.53+341543.6 (d ≃ 322 Mpc) by the Pan-STARRS Survey for Transients. Our data set includes pre-discovery survey data from Pan-STARRS, the All-sky Automated Survey for Supernovae, and the Asteroid Terrestrial-impact Last Alert System as well as high-cadence, multiwavelength follow-up data from ground-based telescopes and Swift, spanning from 56 days before peak light until 75 days after. The optical/UV emission from PS18kh is well-fit as a blackbody with temperatures ranging from T ≃ 12,000 K to T ≃ 25,000 K and it peaked at a luminosity of L ≃ 8.8 × 1043 erg s-1. PS18kh radiated E = (3.45 ± 0.22) × 1050 erg over the period of observation, with (1.42 ± 0.20) × 1050 erg being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked Hα emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the Hα line and its evolution. We find that at early times the high accretion rate leads the disk to emit a wind which modifies the shape of the line profile and makes it bell-shaped. At late times, the wind becomes optically thin, allowing the non-axisymmetric perturbations to show up in the line profile. The line-emitting portion of the disk extends from r in ∼ 60r g to an outer radius of r out ∼ 1400r g and the perturbations can be represented either as an eccentricity in the outer rings of the disk or as a spiral arm in the inner disk.

We present multiwavelength observations of the tidal disruption event (TDE) iPTF15af, discovered by the intermediate Palomar Transient Factory survey at redshift z = 0.07897. The optical and ultraviolet (UV) light curves of the transient show a slow decay over 5 months, in agreement with previous optically discovered TDEs. It also has a comparable blackbody peak luminosity of . The inferred temperature from the optical and UV data shows a value of (3-5) ×10 4 K. The transient is not detected in X-rays up to within the first 5 months after discovery. The optical spectra exhibit two distinct broad emission lines in the He ii region, and at later times also Hα emission. Additionally, emission from [N iii] and [O iii] is detected, likely produced by the Bowen fluorescence effect. UV spectra reveal broad emission and absorption lines associated with high-ionization states of N v, C iv, Si iv, and possibly P v. These features, analogous to those of broad absorption line quasars (BAL QSOs), require an absorber with column densities cm -2 . This optically thick gas would also explain the nondetection in soft X-rays. The profile of the absorption lines with the highest column density material at the largest velocity is opposite that of BAL QSOs. We suggest that radiation pressure generated by the TDE flare at early times could have provided the initial acceleration mechanism for this gas. Spectral UV line monitoring of future TDEs could test this proposal.

Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled ∼200-350 times in 0.3-10 keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these data sets yields three main results: (1) The X-ray/UV correlations are much weaker than those within the UV/optical, posing severe problems for the lamp-post reprocessing model in which variations in a central X-ray corona drive and power those in the surrounding accretion disk. (2) The UV/optical interband lags are generally consistent with as predicted by the centrally illuminated thin accretion disk model. While the average interband lags are somewhat larger than predicted, these results alone are not inconsistent with the thin disk model given the large systematic uncertainties involved. (3) The one exception is the U band lags, which are on average a factor of ∼2.2 larger than predicted from the surrounding band data and fits. This excess appears to be due to diffuse continuum emission from the broad-line region (BLR). The precise mixing of disk and BLR components cannot be determined from these data alone. The lags in different AGN appear to scale with mass or luminosity. We also find that there are systematic differences between the uncertainties derived by JAVELIN versus more standard lag measurement techniques, with JAVELIN reporting smaller uncertainties by a factor of 2.5 on average. In order to be conservative only standard techniques were used in the analyses reported herein.

We present mosaicked long-slit spectral maps of 18 nearby Active GalacticNuclei (AGNs), 2 LINERs, and 4 star-forming galaxies. With the resulting datacubes taken using the Kast dual spectrograph on the 3 m Shane telescope of theLick Observatory, we measure the aperture effects on the spectroscopicclassification of AGNs. With more starlight included in a larger aperture, thenuclear spectrum that is Seyfert-like may become contaminated. We generatedstandard spectroscopic classification diagrams in different observingapertures. These show quantitatively how the ensemble of Seyferts migratestoward the H $\scriptsize{\textrm{II}}$ region classification when beingobserved with increasing aperture sizes. But the effect ranges widely inindividual active galaxies. Some of the less luminous Seyferts shfit by a largeamount, while some other barely move or even shift in different directions. Wefind that those Seyfert galaxies with the fraction of nuclear H$\alpha$emission lower than 0.2 of the host galaxy, 2-10 keV hard X-ray luminositylower than $10^{43}$ erg s$^{-1}$, and the observed nuclear [O$\scriptsize{\textrm{III}}$] luminosity lower than $10^{40.5}$ erg s$^{-1}$,are more likely to change activity classification type when the entire hostgalaxy is included. Overall, 4 of our 24 galaxies (18 Seyferts) change theirspectral activity classification type when observed with a very large aperture.

Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback and AGN fueling. We investigate this concept further with follow-up optical longslit observations of a sample of 95 Sloan Digital Sky Survey (SDSS) galaxies that have double-peaked narrow AGN emission lines. Based on a kinematic analysis of the longslit spectra, we confirm previous work that finds that the majority of double-peaked narrow AGN emission lines are associated with outflows. We also find that eight of the galaxies have companion galaxies with line-of-sight velocity separations

We present the first results from a reverberation-mapping campaign undertaken during the first half of 2012, with additional data on one active galactic nucleus (AGN) (NGC 3227) from a 2014 campaign. Our main goals are (1) to determine the black hole masses from continuum-Hβ 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 Hβ 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 Hβ 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.

We present models of the Hβ-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well as the mass of the central supermassive black hole. We find that the BLR is generally a thick disk, viewed close to face-on, with preferential emission back toward the ionizing source. The dynamics in our sample range from near-circular elliptical orbits to inflowing or outflowing trajectories. We measure black hole masses of for PG 1310-108, for Mrk 50, for Mrk 141, for Mrk 279, for Mrk 1511, for NGC 4593, and for Zw 229-015. We use these black hole mass measurements along with cross-correlation time lags and line widths to recover the scale factor f used in traditional reverberation mapping measurements. Combining our results with other studies that use this modeling technique, which brings our sample size to 16, we calculate a scale factor that can be used for measuring black hole masses in other reverberation mapping campaigns. When using the root-mean-square (rms) spectrum and using the line dispersion to measure the line width, we find pred = 0.57 0.19. Finally, we search for correlations between f and other AGN and BLR parameters and find marginal evidence that f is correlated with M BH and the BLR inclination angle, but no significant evidence of a correlation with the AGN luminosity or Eddington ratio.

We present an analysis using the MOSFIRE Deep Evolution Field (MOSDEF) survey on the nature of "MIR-excess" galaxies, which have star formation rates (SFRs) inferred from mid-infrared (MIR) data that are substantially elevated relative to those estimated from dust-corrected UV data. We use a sample of ∼200 galaxies and active galactic nuclei (AGNs) at 1.40 < z < 2.61 with 24 μm detections (rest-frame 8 μm) from MIPS/Spitzer. We find that the identification of MIR-excess galaxies strongly depends on the methodologies used to estimate IR luminosity (L1R) and to correct the UV light for dust attenuation. We find that extrapolations of the SFR from the observed 24 μm flux, using luminosity-dependent templates based on local galaxies, substantially overestimate in z ∼ 2 galaxies. By including Herschel observations and using a stellar-mass-dependent, luminosity-independent L1R, we obtain more reliable estimates of the SFR and a lower fraction of MIR-excess galaxies. Once stellar-mass selection biases are taken into account, we identify ∼24% of our galaxies as MIR excess. However, is not elevated in MIR-excess galaxies compared to MIR-normal galaxies, indicating that the intrinsic fraction of MIR excess may be lower. Using X-ray-, IR-, and optically selected AGNs in MOSDEF, we do not find a higher prevalence for AGNs in MIR-excess galaxies relative to MIR-normal galaxies. A stacking analysis of X-ray-undetected galaxies does not reveal a harder spectrum in MIR-excess galaxies relative to MIR-normal galaxies. Our analysis indicates that AGN activity does not contribute substantially to the MIR excess and instead implies that it is likely due to the enhanced polycyclic aromatic hydrocarbon emission.

We present results from a systematic selection of tidal disruption events (TDEs) in a wide-area (4800 deg2), g + R band, Intermediate Palomar Transient Factory (iPTF) experiment. Our selection targets typical optically-selected TDEs: bright (>60% flux increase) and blue transients residing in the center of red galaxies. Using photometric selection criteria to down-select from a total of 493 nuclear transients to a sample of 26 sources, we then use follow-up UV imaging with the Neil Gehrels Swift Telescope, ground-based optical spectroscopy, and light curve fitting to classify them as 14 Type Ia supernovae (SNe Ia), 9 highly variable active galactic nuclei (AGNs), 2 confirmed TDEs, and 1 potential core-collapse supernova. We find it possible to filter AGNs by employing a more stringent transient color cut (g - r < -0.2 mag); further, UV imaging is the best discriminator for filtering SNe, since SNe Ia can appear as blue, optically, as TDEs in their early phases. However, when UV-optical color is unavailable, higher precision astrometry can also effectively reduce SNe contamination in the optical. Our most stringent optical photometric selection criteria yields a 4.5:1 contamination rate, allowing for a manageable number of TDE candidates for complete spectroscopic follow-up and real-time classification in the ZTF era. We measure a TDE per galaxy rate of 1.7 - 1.3 + 2.9 × 10 - 4 gal - 1 yr - 1 (90% CL in Poisson statistics). This does not account for TDEs outside our selection criteria, thus may not reflect the total TDE population, which is yet to be fully mapped.

We present the single-epoch black hole mass (M$_{\rm BH}$) calibrations basedon the rest-frame UV and optical measurements of Mg II 2798\AA\ and H$\beta$4861\AA\ lines and AGN continuum, using a sample of 52 moderate-luminosity AGNsat z$\sim$0.4 and z$\sim$0.6 with high-quality Keck spectra. We combine thissample with a large number of luminous AGNs from the Sloan Digital Sky Surveyto increase the dynamic range for a better comparison of UV and opticalvelocity and luminosity measurements. With respect to the reference M$_{\rmBH}$ based on the line dispersion of H$\beta$ and continuum luminosity at5100\AA, we calibrate the UV and optical mass estimators, by determining thebest-fit values of the coefficients in the mass equation. By investigatingwhether the UV estimators show systematic trend with Eddington ratio, FWHM ofH$\beta$, the Fe II strength, and the UV/optical slope, we find no significantbias except for the slope. By fitting the systematic difference of Mg II-basedand H$\beta$-based masses with the L$_{3000}$/L$_{5100}$ ratio, we provide acorrection term as a function of the spectral index as $\Delta$C = 0.24(1+$\alpha_{\lambda}$) + 0.17, which can be added to the Mg II-based massestimators if the spectral slope can be well determined. The derived UV massestimators typically show $>$$\sim$0.2 dex intrinsic scatter with respect toH$\beta$-based M$_{\rm BH}$, suggesting that the UV-based mass has anadditional uncertainty of $\sim$0.2 dex, even if high quality rest-frame UVspectra are available.

We present the single-epoch black hole mass (M$_{\rm BH}$) calibrations basedon the rest-frame UV and optical measurements of Mg II 2798\AA\ and H$\beta$4861\AA\ lines and AGN continuum, using a sample of 52 moderate-luminosity AGNsat z$\sim$0.4 and z$\sim$0.6 with high-quality Keck spectra. We combine thissample with a large number of luminous AGNs from the Sloan Digital Sky Surveyto increase the dynamic range for a better comparison of UV and opticalvelocity and luminosity measurements. With respect to the reference M$_{\rmBH}$ based on the line dispersion of H$\beta$ and continuum luminosity at5100\AA, we calibrate the UV and optical mass estimators, by determining thebest-fit values of the coefficients in the mass equation. By investigatingwhether the UV estimators show systematic trend with Eddington ratio, FWHM ofH$\beta$, the Fe II strength, and the UV/optical slope, we find no significantbias except for the slope. By fitting the systematic difference of Mg II-basedand H$\beta$-based masses with the L$_{3000}$/L$_{5100}$ ratio, we provide acorrection term as a function of the spectral index as $\Delta$C = 0.24(1+$\alpha_{\lambda}$) + 0.17, which can be added to the Mg II-based massestimators if the spectral slope can be well determined. The derived UV massestimators typically show $>$$\sim$0.2 dex intrinsic scatter with respect toH$\beta$-based M$_{\rm BH}$, suggesting that the UV-based mass has anadditional uncertainty of $\sim$0.2 dex, even if high quality rest-frame UVspectra are available.

Dorn-Wallenstein, Levesque, & Ruan recently presented the identification of a z =0.215 active galaxy∼1

The Seyfert 1 galaxy Arp 151 was monitored as part of three reverberation mapping campaigns spanning 2008-2015. We present modeling of these velocity-resolved reverberation mapping data sets using a geometric and dynamical model for the broad-line region (BLR). By modeling each of the three data sets independently, we infer the evolution of the BLR structure in Arp 151 over a total of 7 yr and constrain the systematic uncertainties in nonvarying parameters such as the black hole mass. We find that the BLR geometry of a thick disk viewed close to face-on is stable over this time, although the size of the BLR grows by a factor of ∼2. The dynamics of the BLR are dominated by inflow, and the inferred black hole mass is consistent for the three data sets, despite the increase in BLR size. Combining the inference for the three data sets yields a black hole mass and statistical uncertainty of log10(/) = with a standard deviation in individual measurements of 0.13 dex.

We present a kinematic study of the nuclear stellar disk in M31 at infrared wavelengths using high spatial resolution integral field spectroscopy. The spatial resolution achieved, FWHM = 0.″12 (0.45 pc at the distance of M31), has only previously been equaled in spectroscopic studies by space-based long-slit observations. Using adaptive-optics-corrected integral field spectroscopy from the OSIRIS instrument at the W. M. Keck Observatory, we map the line-of-sight kinematics over the entire old stellar eccentric disk orbiting the supermassive black hole (SMBH) at a distance of r < 4 pc. The peak velocity dispersion is 381 ±55 km s-1, offset by 0.″13 ±0.″03 from the SMBH, consistent with previous high-resolution long-slit observations. There is a lack of near-infrared (NIR) emission at the position of the SMBH and young nuclear cluster, suggesting a spatial separation between the young and old stellar populations within the nucleus. We compare the observed kinematics with dynamical models from Peiris & Tremaine. The best-fit disk orientation to the NIR flux is [θ l, θ i, θ a] = [-33° ±4°, 44° ±2°, -15° ±15°], which is tilted with respect to both the larger-scale galactic disk and the best-fit orientation derived from optical observations. The precession rate of the old disk is ΩP = 0.0 ±3.9 km s-1 pc-1, lower than the majority of previous observations. This slow precession rate suggests that stellar winds from the disk will collide and shock, driving rapid gas inflows and fueling an episodic central starburst as suggested in Chang et al.

We present spectroscopy of emission lines for 81 Seyfert 1 and 104 Seyfert 2galaxies in the IRAS 12$\mu$m galaxy sample. We analyzed the emission-lineluminosity functions, reddening, and other gas diagnostics. The narrow-lineregions (NLR) of Sy1 and 2 galaxies do not significantly differ from each otherin most of these diagnostics. Combining the H$\alpha$/H$\beta$ ratio with a newreddening indicator-the [SII]6720/[OII]3727 ratio, we find the average$E(B-V)=0.49\pm0.35$ for Sy1s and $0.52\pm0.26$ for Sy2s. The NLR of Sy1galaxies has only marginally higher ionization than the Sy2s. Our sampleincludes 22 Sy1.9s and 1.8s. In their narrow lines, these low-luminositySeyferts are more similar to the Sy2s than the Sy1s. We construct a BPTdiagram, and include the Sy1.8s and 1.9s. They overlap the region occupied bythe Sy2s. The C IV equivalent width correlates more strongly with [OIII]/H$\beta$ than with UV luminosity. The Sy1 and Sy2 luminosity functions of[OII]3727 and [OIII]5007 are indistinguishable. Unlike the LF's of Seyfertgalaxies measured by SDSS, ours are nearly flat at low L. The larger number offaint Sloan "AGN" is attributable to their inclusion of weakly emitting LINERsand H II+AGN "composite" nuclei, which do not meet our classification criteriafor Seyferts. An Appendix investigates which emission line luminosities providethe most reliable measures of the total non-stellar luminosity. The hard X-rayor near-ultraviolet continuum luminosity can be crudely predicted from eitherthe [O III]5007 luminosity, or the combination of [O III]+H$\beta$, or [NII]+H$\alpha$ lines, with a scatter of $\pm\,4$ times for the Sy1s and$\pm\,10$ times for the Sy2s. The latter two hybrid (NLR+BLR) indicators havethe advantage of predicting the same HX luminosity independent of Seyfert type.

We present spectroscopy of emission lines for 81 Seyfert 1 and 104 Seyfert 2galaxies in the IRAS 12$\mu$m galaxy sample. We analyzed the emission-lineluminosity functions, reddening, and other gas diagnostics. The narrow-lineregions (NLR) of Sy1 and 2 galaxies do not significantly differ from each otherin most of these diagnostics. Combining the H$\alpha$/H$\beta$ ratio with a newreddening indicator-the [SII]6720/[OII]3727 ratio, we find the average$E(B-V)=0.49\pm0.35$ for Sy1s and $0.52\pm0.26$ for Sy2s. The NLR of Sy1galaxies has only marginally higher ionization than the Sy2s. Our sampleincludes 22 Sy1.9s and 1.8s. In their narrow lines, these low-luminositySeyferts are more similar to the Sy2s than the Sy1s. We construct a BPTdiagram, and include the Sy1.8s and 1.9s. They overlap the region occupied bythe Sy2s. The C IV equivalent width correlates more strongly with [OIII]/H$\beta$ than with UV luminosity. The Sy1 and Sy2 luminosity functions of[OII]3727 and [OIII]5007 are indistinguishable. Unlike the LF's of Seyfertgalaxies measured by SDSS, ours are nearly flat at low L. The larger number offaint Sloan "AGN" is attributable to their inclusion of weakly emitting LINERsand H II+AGN "composite" nuclei, which do not meet our classification criteriafor Seyferts. An Appendix investigates which emission line luminosities providethe most reliable measures of the total non-stellar luminosity. The hard X-rayor near-ultraviolet continuum luminosity can be crudely predicted from eitherthe [O III]5007 luminosity, or the combination of [O III]+H$\beta$, or [NII]+H$\alpha$ lines, with a scatter of $\pm\,4$ times for the Sy1s and$\pm\,10$ times for the Sy2s. The latter two hybrid (NLR+BLR) indicators havethe advantage of predicting the same HX luminosity independent of Seyfert type.

We present results from an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 program to map CO(2-1) emission in nearby early-type galaxies (ETGs) that host circumnuclear gas disks. We obtained ∼0.″3 resolution Band 6 observations of seven ETGs selected on the basis of dust disks in Hubble Space Telescope images. We detect CO emission in five at high signal-to-noise ratio with the remaining two only faintly detected. All CO emission is coincident with the dust and is in dynamically cold rotation. Four ETGs show evidence of rapid central rotation; these are prime candidates for higher-resolution ALMA observations to measure the black hole masses. In this paper, we focus on the molecular gas and continuum properties. Total gas masses and H2 column densities for our five CO-bright galaxies are on average ∼108 M and cm-2 over the ∼kpc-scale disks, and analysis suggests that these disks are stabilized against gravitational fragmentation. The continuum emission of all seven galaxies is dominated by a central unresolved source, and in five we also detect a spatially extended component. The ∼230 GHz nuclear continua are modeled as power laws ranging from Sv ∼ V-0.4 to V1.6 within the observed frequency band. The extended continuum profiles of the two radio-bright (and CO-faint) galaxies are roughly aligned with their radio jet and suggest resolved synchrotron jets. The extended continua of the CO-bright disks are coincident with optically thick dust absorption and have spectral slopes that are consistent with thermal dust emission.

We present results from an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 program to map CO(2-1) emission in nearby early-type galaxies (ETGs) that host circumnuclear gas disks. We obtained ∼0.″3 resolution Band 6 observations of seven ETGs selected on the basis of dust disks in Hubble Space Telescope images. We detect CO emission in five at high signal-to-noise ratio with the remaining two only faintly detected. All CO emission is coincident with the dust and is in dynamically cold rotation. Four ETGs show evidence of rapid central rotation; these are prime candidates for higher-resolution ALMA observations to measure the black hole masses. In this paper, we focus on the molecular gas and continuum properties. Total gas masses and H2 column densities for our five CO-bright galaxies are on average ∼108 M and cm-2 over the ∼kpc-scale disks, and analysis suggests that these disks are stabilized against gravitational fragmentation. The continuum emission of all seven galaxies is dominated by a central unresolved source, and in five we also detect a spatially extended component. The ∼230 GHz nuclear continua are modeled as power laws ranging from Sv ∼ V-0.4 to V1.6 within the observed frequency band. The extended continuum profiles of the two radio-bright (and CO-faint) galaxies are roughly aligned with their radio jet and suggest resolved synchrotron jets. The extended continua of the CO-bright disks are coincident with optically thick dust absorption and have spectral slopes that are consistent with thermal dust emission.

We present ground-based and Swift observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6 Mpc. The light curve of the object peaked at an absolute mag Mg = -17.2. The maximum bolometric luminosity (from optical and UV) was Lp ≃ (1.0 ± 0.15) × 1043erg s-1, an order of magnitude fainter than any other optical TDE discovered so far. The luminosity in the first 60 days is consistent with an exponential decay, with L ∝ e-(t-t0)/τ, where t0 = 57631.0 (MJD) and τ ≃ 15 days. The X-ray shows a marginal detection at LX = 2.41.9-1.1 × 1039 erg s-1 (Swift X-ray Telescope). No radio counterpart was detected down to 3σ, providing upper limits for monochromatic radio luminosities of νLν < 1.7 × 1036 erg s-1 and νLν < 2.3 × 1037 erg s-1 (Very Large Array, 6.1 and 22 GHz). The blackbody temperature, obtained from combined Swift UV and optical photometry, shows a constant value of 19,000 K. The transient spectrum at peak is characterized by broad He ii and Hα emission lines, with FWHMs of about 14,000 km s-1 and 10,000 km s-1, respectively. He i lines are also detected at λλ 5875 and 6678. The spectrum of the host is dominated by strong Balmer absorption lines, which are consistent with a post-starburst (E+A) galaxy with an age of ∼650 Myr and solar metallicity. The characteristics of iPTF16fnl make it an outlier on both luminosity and decay timescales, as compared to other optically selected TDEs. The discovery of such a faint optical event suggests a higher rate of tidal disruptions, as low-luminosity events may have gone unnoticed in previous searches.

We report the discovery by the intermediate Palomar Transient Factory (iPTF) of a candidate tidal disruption event (TDE) iPTF16axa at z = 0.108 and present its broadband photometric and spectroscopic evolution from three months of follow-up observations with ground-based telescopes and Swift. The light curve is well fitted with a t -5/3 decay, and we constrain the rise time to peak to be

Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3-50 keV) and six in the ultraviolet (UV)/optical (1900-5500 Å). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3-4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5-1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the "lamp-post" reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner & Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.

We provide an updated calibration of C iv broad emission line-based single-epoch (SE) black hole (BH) mass estimators for active galactic nuclei (AGNs) using new data for six reverberation-mapped AGNs at redshift with BH masses (bolometric luminosities) in the range106.5-107.5 M⊙(1041.7-1043.8 erg s-1). New rest-frame UV-to-optical spectra covering 1150-5700 Å for the six AGNs were obtained with the Hubble Space Telescope (HST). Multicomponent spectral decompositions of the HST spectra were used to measure SE emission-line widths for the C iv, Mg ii, and Hβ lines, as well as continuum luminosities in the spectral region around each line. We combine the new data with similar measurements for a previous archival sample of 25 AGNs to derive the most consistent and accurate calibrations of the C iv-based SE BH mass estimators against the Hβ reverberation-based masses, using three different measures of broad-line width: full width at half maximum (FWHM), line dispersion (σline), and mean absolute deviation (MAD). The newly expanded sample at redshift z = 0.005-0.234 covers a dynamic range in BH mass (bolometric luminosity) of log MBH M⊙ = 6.5-9.1(log Lbol/erg s-1 = 41.7-46.9), and we derive the new C iv-based mass estimators using a Bayesian linear regression analysis over this range. We generally recommend the use of or MAD rather than FWHM to obtain a less biased velocity measurement of the C iv emission line, because its narrow-line component contribution is difficult to decompose from the broad-line profile.

We provide an updated calibration of C iv broad emission line-based single-epoch (SE) black hole (BH) mass estimators for active galactic nuclei (AGNs) using new data for six reverberation-mapped AGNs at redshift with BH masses (bolometric luminosities) in the range106.5-107.5 M⊙(1041.7-1043.8 erg s-1). New rest-frame UV-to-optical spectra covering 1150-5700 Å for the six AGNs were obtained with the Hubble Space Telescope (HST). Multicomponent spectral decompositions of the HST spectra were used to measure SE emission-line widths for the C iv, Mg ii, and Hβ lines, as well as continuum luminosities in the spectral region around each line. We combine the new data with similar measurements for a previous archival sample of 25 AGNs to derive the most consistent and accurate calibrations of the C iv-based SE BH mass estimators against the Hβ reverberation-based masses, using three different measures of broad-line width: full width at half maximum (FWHM), line dispersion (σline), and mean absolute deviation (MAD). The newly expanded sample at redshift z = 0.005-0.234 covers a dynamic range in BH mass (bolometric luminosity) of log MBH M⊙ = 6.5-9.1(log Lbol/erg s-1 = 41.7-46.9), and we derive the new C iv-based mass estimators using a Bayesian linear regression analysis over this range. We generally recommend the use of or MAD rather than FWHM to obtain a less biased velocity measurement of the C iv emission line, because its narrow-line component contribution is difficult to decompose from the broad-line profile.

We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He ii λ4686 broad emission-line light curves lag that of the 5100 +-optical continuum by 4.17+0.36-0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 ultraviolet continuum light curve measured by the Hubble Space Telescope is ∼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 ∼50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for Hβ 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 Hβ and He ii emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C iv, Lyα, 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 Hβ lag is a factor of five shorter than the expected value implied by the R BLR-L AGN relation based on the past behavior of NGC 5548.

We conduct a multiwavelength continuum variability study of the Seyfert 1 galaxy NGC 5548 to investigate the temperature structure of its accretion disk. The 19 overlapping continuum light curves (1158 A oto 9157 A o) combine simultaneous Hubble Space Telescope, Swift, and ground-based observations over a 180 day period from 2014 January to July. Light-curve variability is interpreted as the reverberation response of the accretion disk to irradiation by a central time-varying point source. Our model yields the disk inclination i = 36° ±10° temperature T1 = 44 ±6 ) × 10 3 K at 1 light day from the black hole, and a temperatureradius slope (T ∞r-a) of a = 0.99 ±0.03. We also infer the driving light curve and find that it correlates poorly with both the hard and soft X-ray light curves, suggesting that the X-rays alone may not drive the ultraviolet and optical variability over the observing period. We also decompose the light curves into bright, faint, and mean accretion-disk spectra. These spectra lie below that expected for a standard blackbody accretion disk accreting at L LEdd = 0.1.

We present a coherent database of spectroscopic observations of far-IRfine-structure lines from the Herschel/PACS archive for a sample of 170 localAGN, plus a comparison sample of 20 starburst galaxies and 43 dwarf galaxies.Published Spitzer/IRS and Herschel/SPIRE line fluxes are included to extend ourdatabase to the full 10-600 $\mu m$ spectral range. The observations arecompared to a set of CLOUDY photoionisation models to estimate the abovephysical quantities through different diagnostic diagrams. We confirm thepresence of a stratification of gas density in the emission regions of thegalaxies, which increases with the ionisation potential of the emission lines.The new [OIV]25.9$\mu m$/[OIII]88$\mu m$ vs [NeIII]15.6$\mu m$/[NeII]12.8$\mum$ diagram is proposed as the best diagnostic to separate: $i)$ AGN activityfrom any kind of star formation; and $ii)$ low-metallicity dwarf galaxies fromstarburst galaxies. Current stellar atmosphere models fail to reproduce theobserved [OIV]25.9$\mu m$/[OIII]88$\mu m$ ratios, which are much higher whencompared to the predicted values. Finally, the ([NeIII]15.6$\mu m$ +[NeII]12.8$\mu m$)/([SIV]10.5$\mu m$ + [SIII]18.7$\mu m$) ratio is proposed asa promising metallicity tracer to be used in obscured objects, where opticallines fail to accurately measure the metallicity. The diagnostic power of mid-to far-infrared spectroscopy shown here for local galaxies will be of crucialimportance to study galaxy evolution during the dust-obscured phase at the peakof the star formation and black-hole accretion activity ($1 < z < 4$). Thisstudy will be addressed by future deep spectroscopic surveys with present andforthcoming facilities such as JWST, ALMA, and SPICA.

We summarize work on the central parsec of the Galactic center based on imaging and spectroscopic observations at the Keck and Gemini telescopes. These observations include stellar positions in two dimension and the velocity in three dimensions. Spectroscopic observations also enables measurements of the physical properties of individual stars, such as the spectral type and in some cases the effective temperature, metallicity, and surface gravity. These observations show a complex stellar population with a young (4-6 Myr) compact star cluster in the central 0.5 pc embedded in in an older and much more massive nuclear star cluster. Surprisingly, the old late-type giants do not show a cusp profile as long been expected from theoretical work. The majority of the stars have higher than solar metallicity, with only about 6% of the stars having [M/Fe] < -0.5, which is consistent with an origin from the MW disk.

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60-70 days, starting ∼75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission line flux deficits occurred for the high ionization, collisionally excited lines C iv and Si iv(+O iv]), and also He ii(+O iii]), while the anomaly in Lywas substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon broad line region (BLR) clouds by a moving veil of material lying between the inner accretion disk and inner (BLR), perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies >54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation.

We present first results from a program of Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) observations of circumnuclear gas disks in early-type galaxies. The program was designed with the goal of detecting gas within the gravitational sphere of influence of the central black holes (BHs). In NGC 1332, the 0.″3-resolution ALMA data reveal CO emission from the highly inclined () circumnuclear disk, spatially coincident with the dust disk seen in Hubble Space Telescope images. The disk exhibits a central upturn in maximum line-of-sight velocity, reaching ±500 km s-1 relative to the systemic velocity, consistent with the expected signature of rapid rotation around a supermassive BH. Rotational broadening and beam smearing produce complex and asymmetric line profiles near the disk center. We constructed dynamical models for the rotating disk and fitted the modeled CO line profiles directly to the ALMA data cube. Degeneracy between rotation and turbulent velocity dispersion in the inner disk precludes the derivation of strong constraints on the BH mass, but model fits allowing for a plausible range in the magnitude of the turbulent dispersion imply a central mass in the range of ∼(4-8) × 108 . We argue that gas-kinematic observations resolving the BH's projected radius of influence along the disk's minor axis will have the capability to yield BH mass measurements that are largely insensitive to systematic uncertainties in turbulence or in the stellar mass profile. For highly inclined disks, this is a much more stringent requirement than the usual sphere-of-influence criterion.

We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of CO(2-1) emission from the circumnuclear disk in the E/S0 galaxy NGC 1332 at 0.″044 resolution. The disk exhibits regular rotational kinematics and central high-velocity emission (±500 km s-1) consistent with the presence of a compact central mass. We construct models for a thin, dynamically cold disk in the gravitational potential of the host galaxy and black hole and fit the beam-smeared model line profiles directly to the ALMA data cube. Model fits successfully reproduce the disk kinematics out to r = 200 pc. Fitting models just to spatial pixels within projected r = 50 pc of the nucleus (two times larger than the black hole's gravitational radius of influence), we find MBH =(6.64+0.65-0.63) × 108 Mo. This observation demonstrates ALMA's powerful capability to determine the masses of supermassive black holes by resolving gas kinematics on small angular scales in galaxy nuclei.

Using archival data from the 2008 Lick AGN Monitoring Project, Zhang & Feng claimed to find evidence for flux variations in the narrow [O III] emission of the Seyfert 1 galaxy Mrk 142 over a two-month time span. If correct, this would imply a surprisingly compact size for the narrow-line region.We show that the claimed [O III] variations are merely the result of random errors in the overall flux calibration of the spectra. The data do not provide any support for the hypothesis that the [OIII] flux was variable during the 2008 monitoring period.

We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 Å to the z band (∼9160 Å). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii and λ1640 and λ4686), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with τ ∝ λ 4 . However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity (L = 0.1 L Edd ). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (∼20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.

The rapid assembly of the massive black holes that power the luminous quasarsobserved at $z \sim 6-7$ remains a puzzle. Various direct collapse models havebeen proposed to head-start black hole growth from initial seeds with masses$\sim 10^5\,\rm M_\odot$, which can then reach a billion solar mass whileaccreting at the Eddington limit. Here we propose an alternative scenario basedon radiatively inefficient super-critical accretion of stellar-mass holesembedded in the gaseous circum-nuclear discs (CNDs) expected to exist in thecores of high redshift galaxies. Our sub-pc resolution hydrodynamicalsimulations show that stellar-mass holes orbiting within the central 100 pc ofthe CND bind to very high density gas clumps that arise from the fragmentationof the surrounding gas. Owing to the large reservoir of dense cold gasavailable, a stellar-mass black hole allowed to grow at super-Eddington ratesaccording to the "slim disc" solution can increase its mass by 3 orders ofmagnitudes within a few million years. These findings are supported bysimulations run with two different hydro codes, RAMSES based on the AdaptiveMesh Refinement technique and GIZMO based on a new Lagrangian Godunov-typemethod, and with similar, but not identical, sub-grid recipes for starformation, supernova feedback, black hole accretion and feedback. The lowradiative efficiency of super-critical accretion flows are instrumental to therapid mass growth of our black holes, as they imply modest radiative heating ofthe surrounding nuclear environment.