Systematic Uncertainties in Black Hole Masses Determined from Single Epoch Spectra

We explore the nature of systematic errors that can arise in measurement of black hole masses from single-epoch spectra of active galactic nuclei (AGNs) by utilizing the many epochs available for NGC 5548 and PG1229+204 from reverberation mapping databases. In particular, we examine systematics due to AGN variability, contamination due to constant spectral components (i.e., narrow lines and host galaxy flux), data quality (i.e., signal-to-noise ratio, S/N), and blending of spectral features by comparing the precision and accuracy of single-epoch mass measurements to those of recent reverberation mapping studies. We calculate masses by characterizing the broad Hbeta emission line by both the full width at half maximum and the line dispersion and demonstrate the importance of removing narrow emission-line components and host starlight. We find that the reliability of line width measurements rapidly decreases for S/N lower than ~10 to 20 (per pixel) and that fitting the line profiles instead of direct measurement of the data does not mitigate this problem but can, in fact, introduce systematic errors. We also conclude that a full spectral decomposition to deblend the AGN and galaxy spectral features is unnecessary except to judge the contribution of the host galaxy to the luminosity and to deblend any emission lines that may inhibit accurate line width measurements. Finally, we present an error budget which summarizes the minimum observable uncertainties as well as the amount of additional scatter and/or systematic offset that can be expected from the individual sources of error investigated. In particular, we find that the minimum observable uncertainty in single-epoch mass estimates due to variability is ~ 20 per pixel) spectra.Comment: 60 pages, 20 figures, accepted for publication in Ap

Determining Quasar Black Hole Mass Functions from their Broad Emission Lines: Application to the Bright Quasar Survey

We describe a Bayesian approach to estimating quasar black hole mass functions (BHMF) when using the broad emission lines to estimate black hole mass. We show how using the broad line mass estimates in combination with statistical techniques developed for luminosity function estimation leads to statistically biased results. We derive the likelihood function for the BHMF based on the broad line mass estimates, and derive the posterior distribution for the BHMF, given the observed data. We develop our statistical approach for a flexible model where the BHMF is modelled as a mixture of Gaussian functions. Statistical inference is performed using markov chain monte carlo (MCMC) methods. Our method has the advantage that it is able to constrain the BHMF even beyond the survey detection limits at the adopted confidence level, accounts for measurement errors and the intrinsic uncertainty in broad line mass estimates, and provides a natural way of estimating the probability distribution of any quantities derived from the BHMF. We conclude by using our method to estimate the local active BHMF using the z < 0.5 Bright Quasar Survey sources. At z = 0.2, the quasar BHMF falls off approximately as a power law with slope ~ 2 for M_{BH} > 10^8. Our analysis implies that z < 0.5 broad line quasars have a typical Eddington ratio of ~ 0.4 and a dispersion in Eddington ratio of < 0.5 dex (abridged).Comment: 25 pages, 14 figures, emulate ApJ style, accepted by Ap

X-ray Emission from the Radio Jet in 3C 120

We report the discovery of X-ray emission from a radio knot at a projected distance of 25" from the nucleus of the Seyfert galaxy, 3C 120. The data were obtained with the ROSAT High Resolution Imager (HRI). Optical upper limits for the knot preclude a simple power law extension of the radio spectrum and we calculate some of the physical parameters for thermal bremsstrahlung and synchrotron self-Compton models. We conclude that no simple model is consistent with the data but if the knot contains small regions with flat spectra, these could produce the observed X-rays (via synchrotron emission) without being detected at other wavebands.Comment: 6 pages latex plus 3 ps/eps figures. Uses 10pt.sty and emulateapj.sty. Accepted for publication in the ApJ (6 Jan 99

Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurization and correlation to sensory analysis

Volatile compounds in skim milk and nonstandardised milk subjected to instant infusion pasteurisation at 80°C, 100°C and 120°C were compared with raw milk, high temperature short time pasteurised milk and milk pasteurised at 85°C/30 s. The composition of volatile compounds differed between infusion pasteurisation treated samples and the reference pasteurisations. The sensory properties of skim milk subjected to instant infusion pasteurisation were described by negative attributes, such as cardboard sour and plastic flavours, which are not associated normally with fresh milk. Partial least squares modelling showed good correlation between the volatile compounds and the sensory properties, indicating the predictive and possible causal importance of the volatile compounds for the sensory characteristics

Reverberation Mapping Results from MDM Observatory

We present results from a multi-month reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from around the world. We measure broad line region (BLR) radii and black hole masses for six objects. A velocity-resolved analysis of the H_beta response shows the presence of diverse kinematic signatures in the BLR.Comment: To appear in the Proceedings of the IAU Symposium No. 267: Co-Evolution of Central Black Holes and Galaxies, Rio de Janeiro, 200

Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption

We present Gemini near-infrared spectroscopic observations of six luminous quasars at z=5.8$\sim$6.3. Five of them were observed using Gemini-South/GNIRS, which provides a simultaneous wavelength coverage of 0.9--2.5 $\mu$m in cross dispersion mode. The other source was observed in K band with Gemini-North/NIRI. We calculate line strengths for all detected emission lines and use their ratios to estimate gas metallicity in the broad-line regions of the quasars. The metallicity is found to be supersolar with a typical value of $\sim$4 Z_{\sun}, and a comparison with low-redshift observations shows no strong evolution in metallicity up to z$\sim$6. The FeII/MgII ratio of the quasars is 4.9+/-1.4, consistent with low-redshift measurements. We estimate central BH masses of 10^9 to 10^{10} M_{\sun} and Eddington luminosity ratios of order unity. We identify two MgII $\lambda\lambda$2796,2803 absorbers with rest equivalent width W_0^{\lambda2796}>1 \AA at 2.2<z<3 and three MgII absorbers with W_0^{\lambda2796}>1.5 \AA at z>3 in the spectra, with the two most distant absorbers at z=4.8668 and 4.8823, respectively. The redshift number densities (dN/dz) of MgII absorbers with W_0^{\lambda2796}>1.5 \AA are consistent with no cosmic evolution up to z>4.Comment: 33 pages (including 7 figures and 6 tables), AJ in pres

Spectroscopy of Broad Line Blazars from 1LAC

We report on optical spectroscopy of 165 Flat Spectrum Radio Quasars (FSRQs) in the Fermi 1LAC sample, which have helped allow a nearly complete study of this population. Fermi FSRQ show significant evidence for non-thermal emission even in the optical; the degree depends on the gamma-ray hardness. They also have smaller virial estimates of hole mass than the optical quasar sample. This appears to be largely due to a preferred (axial) view of the gamma-ray FSRQ and non-isotropic (H/R ~ 0.4) distribution of broad-line velocities. Even after correction for this bias, the Fermi FSRQ show higher mean Eddington ratios than the optical population. A comparison of optical spectral properties with Owens Valley Radio Observatory radio flare activity shows no strong correlation.Comment: Accepted for publication in Ap

Parsec-scale radio morphology and variability of a changing-look AGN: the case of Mrk 590

We investigate the origin of the parsec-scale radio emission from the changing-look active galactic nucleus (AGN) of Mrk 590, and examine whether the radio power has faded concurrently with the dramatic decrease in accretion rates observed between the 1990s and the present. We detect a compact core at 1.6 GHz and 8.4 GHz using new Very Long Baseline Array observations, finding no significant extended, jet-like features down to $\sim$1 pc scales. The flat spectral index ($\alpha_{1.6}^{8.4} = 0.03$) and high brightness temperature ($T_{\rm b} \sim 10^{8}\,\rm K$) indicate self-absorbed synchrotron emission from the AGN. The radio to X-ray luminosity ratio of ${\rm log}(L_{\rm R}/L_{\rm X}) \sim -5$, similar to that in coronally active stars, suggests emission from magnetized coronal winds, although unresolved radio jets are also consistent with the data. Comparing new Karl G. Jansky Very Large Array measurements with archival and published radio flux densities, we find $46\%$, $34\%$, and (insignificantly) $13\%$ flux density decreases between the 1990s and the year 2015 at 1.4 GHz, 5 GHz and 8.4 GHz respectively. This trend, possibly due to the expansion and fading of internal shocks within the radio-emitting outflow after a recent outburst, is consistent with the decline of the optical-UV and X-ray luminosities over the same period. Such correlated variability demonstrates the AGN accretion-outflow connection, confirming that the changing-look behaviour in Mrk 590 originates from variable accretion rates rather than dust obscuration. The present radio and X-ray luminosity correlation, consistent with low/hard state accretion, suggests that the black hole may now be accreting in a radiatively inefficient mode.Comment: 14 pages, 5 tables, 5 figures, accepted for publication in MNRA

The optical spectrum of PKS 1222+216 and its black hole mass

We investigate the optical spectral properties of the blazar PKS 1222+216 during a period of 3 years. While the continuum is highly variable the broad line emission is practically constant. This supports a scenario in which the broad line region is not affected by jet continuum variations. We thus infer the thermal component of the continuum from the line luminosity and we show that it is comparable with the continuum level observed during the phases of minimum optical activity. The mass of the black hole is estimated through the virial method from the FWHM of MgII, Hbeta, and Halpha broad lines and from the thermal continuum luminosity. This yields a consistent black hole mass value of 6x10^8 solar masses.Comment: 7 pages, 4 figures, accepted for publication in MNRA

Coccidiose hos kvæg: En oversigt over coccidiearter, patogenese, epidemiologi og forebyggelse specielt i økologiske besætninger

Coccidiose hos kalve forårsages af arter af de encellede parasitter, Eimeria, der findes vidt udbredt i alle verdensdele, og som giver anledning til diarré og utrivelighed hos især unge og modtagelige dyr. Hos kvæg findes 12 forskellige Eimeria arter, der adskiller sig fra hinanden med hensyn til morfologi, livscyklus og patogenitet. Infektion med Eimeria kan diagnosticeres ved forskellige la-boratoriemetoder, hvorved bl.a. antallet og arten af coccidier forsøges fastslået. Således skabes grundlag for bestemmelse af hvilke forebyggende tiltag, der eventuelt bør iværksættes. Ved under-søgelse af 258 kalve fra 25 danske økologiske malkekvægsbesætninger fandt vi Eimeria-arter i alle (100%) besætninger og i 88% af kalvene. De fleste kalve udskilte meget lavgradige mængder af coccidier i gødningen, medens nogle havde særdeles høje coccidieudskillelser. Coccidiose er en multifaktoriel sygdom, og sværhedsgraderne af sygdommen varierer derfor fra subkliniske tilfælde til nogle med løs, pastøs fæces af en enkelt dags varighed eller profus diarré med dysenteri, tenesmus og evt. mors. De kliniske symptomer tillægges traditionelt tilstedeværelsen af coccidiearterne Eimeria zuernii og E. bovis. Kalvens modtagelighed for coccidiose afhænger bl.a. af råmælksforsyning og immunitet, ernæringsstatus, stress, og evt. forekomst af andre sygdomme (f.eks. samtidige helminth- eller virusinfektioner). Endelig har også miljøet betydning for udvikling af coccidiose, herunder opstaldningstæthed, klima og hygiejne. Total udryddelse af coccidier er ikke muligt pga. parasittens ubikvitære forekomst og resistens i miljøet, men kalven kan styrkes ved sikring af tilstrækkelige råmælksmængder og ved opretholdelse af høj hygiejne i kælvningsboksen, samt efterfølgende opstaldningsforhold. Aktiv immunisering (vaccination) har endnu ikke vist sig effektiv i større målestok. Der foreligger ikke yderligere retningslinier for forebyggelse i perspektiv af de økologiske regler. Kalve, der har klinisk coccidiose, bør isoleres fra de øvrige kalve og gives væsketerapi for at opretholde væskebalancen. Den bedste behandling er imidlertid forebyggelse - med fokus på belægningsgrad og høj hygiejne inklusive rigeligt med tør strøelse