Search

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 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

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

The K2 mission is targeting large numbers of nearby (d < 100 pc) GKM dwarfs selected from the SUPERBLINK proper motion survey (μ > 40 mas yr^(−1), V < 20). Additionally, the mission is targeting low-mass, high proper motion stars associated with the local (d < 500 pc) Galactic halo population also selected from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 26,518 of these cool main-sequence stars. We used the auto-correlation function to search for fast rotators by identifying short-period photometric modulations in the K2 light curves. We identified 481 candidate fast rotators with rotation periods

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 ground-based optical photometric monitoring data for NGC 5548, part of an extended multi-wavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (\emph{BVRI} and \emph{ugriz}). Combined with ultraviolet data from the \emph{Hubble Space Telescope} and \emph{Swift}, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158\,\AA\ to the $z$ band ($\sim\!9160$\,\AA). We find that the lags at wavelengths longer than the {\it V} band are equal to or greater than the lags of high-ionization-state emission lines (such as He\,{\sc ii}\,$\lambda 1640$ and $\lambda 4686$), 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 $\tau \propto \lambda^{4/3}$. 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 ($L = 0.1L_{\rm Edd}$). 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 ($\sim\! 20\%$) can be important for the shortest continuum lags, and likely has a significant impact on the {\it u} and {\it U} bands owing to Balmer continuum emission., Comment: 26 pages, 10 figures, accepted to ApJ. For a brief video describing the main results of this paper, please see: https://www.youtube.com/watch?v=yaYtcDvIoP0&feature=youtu.be

We present the results of a recent reverberation mapping campaign for UGC 06728, a nearby low-luminosity Seyfert 1 in a late-type galaxy. Nightly monitoring in the spring of 2015 allowed us to determine an H$\beta$ time delay of $\tau = 1.4 \pm 0.8$ days. Combined with the width of the variable H$\beta$ line profile, we determine a black hole mass of $M_{\rm BH} = (7.1 \pm 4.0) \times 10^5$ M$_{\odot}$. We also constrain the bulge stellar velocity dispersion from higher-resolution long slit spectroscopy along the galaxy minor axis and find $\sigma_{\star} = 51.6 \pm 4.9$ km s$^{-1}$. The measurements presented here are in good agreement with both the $R_{\rm BLR} - L$ relationship and the $M_{\rm BH}-\sigma_{\star}$ relationship for AGNs. Combined with a previously published spin measurement, our mass determination for UGC 06728 makes it the lowest-mass black hole that has been fully characterized, and thus an important object to help anchor the low-mass end of black hole evolutionary models., Comment: accepted for publication in ApJ; 10 pages, 10 figures, 5 tables

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 to 9157 angstroms) combine simultaneous HST , 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, temperature T1 at 1 light day from the black hole, and a temperature-radius slope, alpha. 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, Comment: V2: Oops wrong title! V1: Accepted for publication in ApJ, 20 Pages, 11 Figures

We present the results of a reverberation-mapping program targeting NGC5273, a nearby early-type galaxy with a broad-lined active galactic nucleus. Over the course of the monitoring program, NGC5273 showed strong variability that allowed us to measure time delays in the responses of the broad optical recombination lines to changes in the continuum flux. A weighted average of these measurements results in a black hole mass determination of $M_{\rm BH} = (4.7 \pm 1.6) \times 10^6$ M$_{\odot}$. An estimate of the size of the black hole sphere of influence in NGC5273 puts it just at the limit of the resolution achievable with current ground-based large aperture telescopes. NGC5273 is therefore an important future target for a black hole mass determination from stellar dynamical modeling, especially because it is the only nearby early-type galaxy hosting an AGN with a reverberation-based mass, allowing the best comparison for the masses determined from these two techniques., 10 pages, 7 figures, 3 tables, accepted for publication in ApJ

Long-term feedlot studies have shown positive effects (i.e., improved ADG and reduced morbidity and mortality) of dietary supplementation with ethoxyquin (AGRADO). This may be due to improving the antioxidant capacity at the ruminal, postruminal, or postabsorption levels. This study was designed to investigate the role of ethoxyquin at the rumen level. A finishing diet (12.5% CP; DM basis) was formulated to contain (on a DM basis) 77.5% flaked corn, 10% corn cobs, 10% protein/vitamin/mineral supplement, and 2.5% tallow. In a randomized complete block design experiment, the treatments were arranged as a 2 x 2 factorial. The main factors were two ethoxyquin treatments (without or with 150 ppm) and two monensin/tylosin treatments (without or with monensin and tylosin at 0.0028 and 0.0014% of dietary DM, respectively). Eight dual-flow, continuous culture fermenters were used in two experimental periods (blocks; 8 d each with 5 d for adjustment and 3 d for sample collection) to allow for four replications for each treatment. No interactions (P0.05) were detected for any of the measurements evaluated. Therefore, results of the main factors were summarized. Ethoxyquin supplementation improved (P0.05) true digestibility of OM (from 38.8 to 45.0%) but it did not alter (P0.05) concentrations of total VFA (averaging 131 mM) or acetate (averaging 58.8 mM). Ethoxyquin decreased (P0.05) propionate concentration from 51.1 to 42.4 mM and increased (P0.05) butyrate concentration from 18.4 to 22.9 mM. Digestion of total nonstructural carbohydrates was not altered (P0.05) by the treatments and averaged 86%. With the exception of increased (P0.05) concentration of propionate (from 42.0 to 51.5 mM) and decreased (P0.05) concentration of butyrate (from 25.9 to 16.3 mM), no effects (P0.05) were detected for monensin/tylosin. Ruminal N metabolism, including efficiency of bacterial protein synthesis (averaging 21.2 g N/kg OM truly digested), was not affected (P0.05) by the treatments. Results suggest positive effects of ethoxyquin on ruminal digestion of OM and unique changes in VFA production.

The $^{3}\mathrm{He}$ magnetic form factor has been measured for momentum transfers between 0.7 and 11 ${\mathrm{fm}}^{\ensuremath{-}2}$ with improved precision over previous measurements. The charge form factor has been measured for momentum transfers less than 1 ${\mathrm{fm}}^{\ensuremath{-}2}$. The charge radius was determined to be 1.935\ifmmode\pm\else\textpm\fi{}0.03 fm, and the magnetic radius 1.935\ifmmode\pm\else\textpm\fi{}0.04 fm. Comparisons are made with calculations which include meson exchange corrections and reasonable agreement is found.NUCLEAR REACTIONS $d(e, {e}^{\ensuremath{'}})d$, ${q}^{2}=0.7 \mathrm{to} 11$ ${\mathrm{fm}}^{\ensuremath{-}2}$, $\ensuremath{\theta}=160\ifmmode^\circ\else\textdegree\fi{}$, measured magnetic form factor; ${q}^{2}l1$ ${\mathrm{fm}}^{\ensuremath{-}2}$, $\ensuremath{\theta}=60\ifmmode^\circ\else\textdegree\fi{}$, measured charge radius.

This paper reports the first measurement of the tensor polarization t/sub 20/ in e-d elastic scattering. The polarization of the recoil deuterons was measured for two values of momentum transfer, q = 1.74 and 2.03 fm/sup -1/, with a high-efficiency polarimeter. The results are in good agreement with reasonable models for the deuteron.

We investigate the possibility of using perturbation theory to compute the binding energy for infinite systems in which the particles are localized. For the case of the linear chain of coupled harmonic oscillators, we prove that the perturbation series for the ground‐state energy per particle is convergent. Exact expressions for the generalized Pade approximants are derived. The generalized approximants provide a manifestly convergent sequence of approximations to the energy.

Our spray program is far from reaching its optimal stage at this time. For example, we are not sure that we have the best technique to spray tar-impregnated brick; and if the dolomitic variety of refractories requires a different spraying approach than the magnesite variety. In addition, we are attempting to make the spraying practice more uniform by examining the feasibility of incorporating an automatic spray machine in the shop.

A boundary condition model for proton-proton scattering, which features potential tails, was found to yield a good description of the p-p data up to 310 Mev. The boundary conditions were applied at the same radius for all states of a given spin angular momentum. Preliminary values of the boundary conditions were obtained by inward stepwise calculations of the wave functions for each state. The boundar condition method was also tried with the one-pion exchange potential in the outer region. (M.C.G.)