Setting the Standard for Farmland Preservation: Do Preservation Criteria Motivate Citizen Support for Farmland Preservation?

The multifunctional set of services provided by farmland complicates the task of identifying which farmland should be preserved. For this reason many states and local governments establish criteria to rank and select parcels of farmland for protection. This study examines whether criteria commonly used by state programs to guide purchases of agricultural conservation easements influence public demand for farmland preservation. The results provide policy makers with additional information to assess current ranking criteria that set the standard for farmland preservation.Land Economics/Use,

Compact Radio Cores in Seyfert Galaxies

We have observed a sample of 157 Seyfert galaxies with a 275 km baseline radio interferometer to search for compact, high brightness temperature radio emission from the active nucleus. We obtain the surprising result that compact radio cores are much more common in Seyfert 2 than in Seyfert 1 galaxies, which at first seems to be inconsistent with orientation unification schemes. We propose a model, involving optical depth effects in the narrow-line region, which can reconcile our result with the standard unified scheme. (Accepted for publication in ApJ 1994 Sep 10)Comment: 21 pages and 7 figures, uuencoded tar-compressed postscript files, ATP18

Net Buyers, Net Sellers, and Agricultural Landowner Support for Agricultural Zoning

Agricultural zoning and land use restrictions are long-standing approaches for controlling non-agricultural development. Agricultural landowners may contest agricultural zoning if they expect zoning to reduce land prices on restricted land. However, it is common to find agricultural landowners on both sides of this issue. A prevailing economic explanation for variation in landowner support is that the price effect of zoning varies across land parcels and therefore, zoning may increases the value of some lands zoned for agricultural use. In this paper, we provide an additional explanation for variation in agricultural landowner support. We use the concepts of net buyers and net sellers of land to suggest that the utility effect of changing land prices depends on an agricultural landowner's position in the agricultural land market. Hence, even in situations where all agricultural landowners expect zoning to reduce agricultural land prices, some subset of agricultural landowners - i.e., net buyers - may benefit. Survey data from agricultural landowners is used to model the probability that an agricultural landowner will support agricultural zoning. The empirical findings are consistent with our hypothesis that net buyers and net sellers of agricultural land will differ in their support for agricultural zoning.Land Economics/Use,

Are the hosts of VLBI selected radio-AGN different to those of radio-loud AGN?

Recent studies have found that radio-AGN selected by radio-loudness show little difference in terms of their host galaxy properties when compared to non-AGN galaxies of similar stellar mass and redshift. Using new 1.4~GHz VLBI observations of the COSMOS field we find that approximately 49$\pm8$\% of high-mass (M $>$ 10$^{10.5}$ M$_{\odot}$), high luminosity (L$_{1.4}$ $>$ 10$^{24}$ W~Hz$^{-1}$) radio-AGN possess a VLBI detected counterpart. These objects show no discernible bias towards specific stellar masses, redshifts or host properties other than what is shown by the radio-AGN population in general. Radio-AGN that are detected in VLBI observations are not special, but form a representative sample of the radio-loud AGN population.Comment: 6 pages, 4 figures, lette

A wider audience: Turning VLBI into a survey instrument

Radio observations using the Very Long Baseline Interferometry (VLBI) technique typically have fields of view of only a few arcseconds, due to the computational problems inherent in imaging larger fields. Furthermore, sensitivity limitations restrict observations to very compact and bright objects, which are few and far between on the sky. Thus, while most branches of observational astronomy can carry out sensitive, wide-field surveys, VLBI observations are limited to targeted observations of carefully selected objects. However, recent advances in technology have made it possible to carry out the computations required to target hundreds of sources simultaneously. Furthermore, sensitivity upgrades have dramatically increased the number of objects accessible to VLBI observations. The combination of these two developments have enhanced the survey capabilities of VLBI observations such that it is now possible to observe (almost) any point in the sky with milli-arcsecond resolution. In this talk I review the development of wide-field VLBI, which has made significant progress over the last three years.Comment: Invited review at the General Assembly of the Astronomische Gesellschaf

Chemical Abundances of new member stars in the Tucana II dwarf galaxy

We present chemical abundance measurements for seven stars with metallicities ranging from [Fe/H] = $-$3.3 to [Fe/H] = $-$2.4 in the Tucana II ultra-faint dwarf galaxy (UFD), based on high-resolution spectra obtained with the MIKE spectrograph on the 6.5 m Magellan-Clay Telescope. For three stars, we present detailed chemical abundances for the first time. Of those, two stars are newly discovered members of Tucana II and were selected as probable members from deep narrow band photometry of the Tucana II UFD taken with the SkyMapper telescope. This result demonstrates the potential for photometrically identifying members of dwarf galaxy systems based on chemical composition. One new star was selected from the membership catalog of Walker et al. (2016). The other four stars in our sample have been re-analyzed, following additional observations. Overall, six stars have chemical abundances that are characteristic of the UFD stellar population. The seventh star shows chemical abundances that are discrepant from the other Tucana II members and an atypical, higher strontium abundance than what is expected for typical UFD stars. While unlikely, its strontium abundance raises the possibility that it may be a foreground metal-poor halo star with the same systemic velocity as Tucana II. If we were to exclude this star, Tucana II would satisfy the criteria to be a surviving first galaxy. Otherwise, this star implies that Tucana II has likely experienced somewhat extended chemical evolution.Comment: 20 pages, 6 figures, 5 tables; Accepted for publication in ApJ. Changes w.r.t. v1: corrected coordinates for TucII-078 in Table

Observation of ground-state quantum beats in atomic spontaneous emission

We report ground-state quantum beats in spontaneous emission from a continuously driven atomic ensemble. Beats are visible only in an intensity autocorrelation and evidence spontaneously generated coherence in radiative decay. Our measurement realizes a quantum eraser where a first photon detection prepares a superposition and a second erases the "which-path" information in the intermediate state.Comment: 4 pages, 4 figures, to appear in Phys. Rev. Letter

COLA. III. Radio Detection of Active Galactic Nucleus in Compact Moderate Luminosity Infrared Galaxies

We present results from 4.8 GHz Very Large Array (VLA) and global very long baseline interferometry (VLBI) observations of the northern half of the moderate FIR luminosity (median L_(IR) = 10^(11.01) L_☉) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the galaxies observed. The radio luminosities of these cores (~10^(21) W Hz^(–1)) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by active galactic nuclei (AGNs). These sub-parsec scale radio cores are preferentially detected toward galaxies whose VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star formation, we conclude that the AGN-powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central supermassive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity