Black-Hole Mass Measurements

The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.Comment: 6 pages. Invited review at `AGN Physics with the Sloan Digital Sky Survey' conference (July 2003), eds. G. Richards and P. Hall (ASP Conf. Series, 2004

Meat quality of hull calves fed only grass or only herbs for 8 weeks prior to slaughter matches that of concentrate-fed bull calves

The organic rules require that bull calves are raised outdoor at least 6 months a year in Denmark and are fed at least 60% roughage of the total diet. These rules are a constraint for an organic production of beef based on the bull calves born in the organic dairy herds because of extra labor costs, expected lower growth rate, difficulties in raising bull calves outdoor, possibly lower meat quality and lack of sufficiently high organic premium payment for the carcass. Thus, the bull calves are sold for conventional fattening. The supply of organic beef from young cattle is concomitantly very limited. However, in order to obtain the necessary higher payment for beef from organic-raised young cattle, it is important that consumers like the beef from grass- and herb-fed young cattle

An Empirical Ultraviolet Iron Spectrum Template Applicable to Active Galaxies

Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and FeIII templates for ultraviolet active galaxy spectra based on HST archival 1100 - 3100 A spectra of IZw1. Their application allows fitting and subtraction of the iron emission in active galaxy spectra. This work has shown that in particular CIII] lambda 1909 can be heavily contaminated by other line emission, including iron transitions. Details of the data processing, generation, and use of the templates, are given by Vestergaard & Wilkes (2001).Comment: 4 pages, including 1 figure, to appear in "Spectroscopic Challenges of Photoionized Plasmas", ASP Conf. Series, Eds. Gary Ferland and Daniel Wolf Savi

Eating quality of Holstein bull calves fed only grass or purely herbs matches that of concentrate-fed veal calves

Organic meat production from Holstein calves born in dairy herds require that the bull calves are raised outdoor at least 6 months a year, and on large quantities of roughage in the diet. This study aimed at elucidating if Holstein bull calves fed either purely grass or purely herbs prior to slaughter would differ in meat quality traits, fatty acid composition and sensory profile and if they differed in quality aspects from concentrate-fed veal calves

Black Hole Masses of High-Redshift Quasars

Black-hole masses of distant quasars cannot be measured directly, but can be estimated to within a factor 3 to 5 using scaling relationships involving the quasar luminosity and broad-line width. Why such relationships are reasonable is summarized. The results of applying scaling relationships to data of quasars at a range of redshifts (z <= 6.3) are presented. Luminous quasars typically have masses of order 1 billion solar masses even at the highest redshifts. The fact that such massive black holes appear as early as at z ~ 6 indicate that black holes form very early or build up mass very fast.Comment: 4 pages with 2 figures, to appear in proceedings of Multiwavelength AGN Surveys, ed. R. Mujica and R. Maiolino (Singapore: World Scientific), 200

A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey

We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The comparison between the N-rich quasars and other quasars shows that the two quasar subsets share many common properties. We also confirm previous results that N-rich quasars have much stronger Lya and NV lambda 1240 emission lines. Strong nitrogen emission in all ionization states indicates high overall nitrogen abundances in these objects. We find evidence that the nitrogen abundance is closely related to quasar radio properties. The radio-loud fraction in the NIII]-rich quasars is 26% and in the NIV]-rich quasars is 69%, significantly higher than ~8% measured in other quasars with similar redshift and luminosity. Therefore, the high nitrogen abundance in N-rich quasars could be an indicator of a special quasar evolution stage, in which the radio activity is also strong.Comment: 8 pages, 4 figures; accepted by ApJ (ApJ June 10, 2008, v680 n1 issue

Determining Central Black Hole Masses in Distant Active Galaxies

An empirical relationship, of particular interest for studies of high redshift active galactic nuclei (AGNs) and quasars, between the masses of their central black-holes and rest-frame ultraviolet (UV) parameters measured in single-epoch AGN spectra is presented. This relationship is calibrated to recently measured reverberation masses of low-redshift AGNs and quasars. An empirical relationship between single-epoch rest-frame optical spectrophotometric measurements and the central masses is also presented. The UV relationship allows reasonable estimates of the central masses to be made of high-redshift AGNs and quasars for which these masses cannot be directly or easily measured by the techniques applicable to the lower luminosity, nearby AGNs. The central mass obtained by this method can be estimated to within a factor of ~3 for most objects. This is reasonable given the intrinsic uncertainty of a factor less than 2 in the primary methods used to measure the central masses of nearby inactive and active galaxies, namely resolved gas and stellar kinematics in the underlying host galaxy and reverberation-mapping techniques. The UV relationship holds good potential for being a powerful tool to study black-hole demographics at high redshift as well as to statistically study the fundamental properties of AGNs. The broad line region size - luminosity relationship is key to the calibrations presented here. The fact that its intrinsic scatter is also the main source of uncertainty in the calibrations stresses the need for better observational constraints to be placed on this relationship. The empirically calibrated relationships presented here will be applied to quasar samples in forthcoming work

Green veal is not dark red

Among many farmers, butchers and consumers, the expectation is that meat arising from grazing cattle generally is darker than meat from cattle primarily fed cereals. Without necessarily being the truth, this dogma is a constraint to the marketing of ‘green’ meat. In an attempt to increase the supply of organic meat from young cattle, we need to know which quality parameters are the characteristics for this type of meat, including colour characteristics

High Redshift Standard Candles: Predicted Cosmological Constraints

We investigate whether future measurements of high redshift standard candles (HzSCs) will be a powerful probe of dark energy, when compared to other types of planned dark energy measurements. Active galactic nuclei and gamma ray bursts have both been proposed as potential HzSC candidates. Due to their high luminosity, they can be used to probe unexplored regions in the expansion history of the universe. Information from these regions can help constrain the properties of dark energy, and in particular, whether it varies over time. We consider both linear and piecewise parameterizations of the dark energy equation of state, $w(z)$, and assess the optimal redshift distribution a high-redshift standard-candle survey could take to constrain these models. The more general the form of the dark energy equation of state $w(z)$ being tested, the more useful high-redshift standard candles become. For a linear parameterization of $w(z)$, HzSCs give only small improvements over planned supernova and baryon acoustic oscillation measurements; a wide redshift range with many low redshift points is optimal to constrain this linear model. However to constrain a general, and thus potentially more informative, form of $w(z)$, having many HzSCs can significantly improve limits on the nature of dark energy.Comment: Accepted MNRAS, 27 Pages, 15 figures, matches published versio