3,929 research outputs found

    Understanding Arguments to Protect Farmland in Idaho: Innovative Solutions and Community Insights to Drive Policy Change

    Get PDF
    Between Spring 2022 and Spring 2023, a team of researchers at Boise State University conducted interviews with people involved in farmland protection efforts. Our goal was to understand how interviewees frame the issue of farmland loss. Frames can draw attention to an issue, contextualize decision-making, and influence the policy solutions considered. Through a frame analysis, we gained a clearer understanding of potential approaches for farmland protection in Idaho. We conducted 10 semi-structured interviews with individuals representing government agencies, academic institutions, land trusts, non-profit organizations, and farmers. After conducting the interviews, we analyzed the transcripts in a systematic manner to identify recurring message frames pertaining to farmland loss. The analysis process enabled us to map these frames onto potential policy solutions applicable to Idaho. Our report outlines the advantages and disadvantages of each frame and pinpoints which ones are likely to resonate with specific groups. Our research revealed a diverse range of frames used to address farmland protection, with many interviewees citing multiple frames. The domestic food security, regional economy, and national/global trade frames are expected to have broad appeal, while the national security and environmental benefits frames may appeal to more specific audiences. The threatened resource and cultural importance frames are likely to resonate with those valuing tradition. We identified a variety of solutions, such as agricultural protection areas, support for rural economies, promotion of regenerative agriculture, and expansion of Idaho\u27s Right to Farm Act protections. Our findings underscore the importance of diverse, flexible, and responsive solutions to improve the feasibility of farmland protection in Idaho. We hope that our work will provide a solid basis for future efforts aimed at preserving Idaho\u27s farmland

    Chandra Observations of Radio-Loud Quasars at z > 4: X-rays from the Radio Beacons of the Early Universe

    Full text link
    We present the results of Chandra observations of six radio-loud quasars (RLQs) and one optically bright radio-quiet quasar (RQQ) at z = 4.1-4.4. These observations cover a representative sample of RLQs with moderate radio-loudness (R ~ 40-400), filling the X-ray observational gap between optically selected RQQs and the five known blazars at z > 4 (R ~ 800-27000). We study the relationship between X-ray luminosity and radio-loudness for quasars at high redshift and constrain RLQ X-ray continuum emission and absorption. From a joint spectral fit of nine moderate-R RLQs observed by Chandra, we find tentative evidence for absorption above the Galactic N_H, with a best-fit neutral intrinsic column density of N_H = 2.4^{+2.0}_{-1.8} x 10^{22} cm^{-2}, consistent with earlier claims of increased absorption toward high-redshift RLQs. We also search for evidence of an enhanced jet-linked component in the X-ray emission due to the increased energy density of the cosmic microwave background (CMB) at high redshift, but we find neither spatial detections of X-ray jets nor a significant enhancement in the X-ray emission relative to comparable RLQs at low-to-moderate redshifts. Overall, the z ~ 4-5 RLQs have basic X-ray properties consistent with comparable RLQs in the local universe, suggesting that the accretion/jet mechanisms of these objects are similar as well.Comment: 12 pages, The Astronomical Journal, in pres

    The X-Ray Properties of the Optically Brightest Mini-BAL Quasars from the Sloan Digital Sky Survey

    Get PDF
    We have compiled a sample of 14 of the optically brightest radio-quiet quasars (mim_{i}~\le~17.5 and zz~\ge~1.9) in the Sloan Digital Sky Survey Data Release 5 quasar catalog that have C IV mini-BALs present in their spectra. X-ray data for 12 of the objects were obtained via a Chandra snapshot survey using ACIS-S, while data for the other two quasars were obtained from archival XMM-Newton observations. Joint X-ray spectral analysis shows the mini-BAL quasars have a similar average power-law photon index (Γ1.9\Gamma\approx1.9) and level of intrinsic absorption (NH8×1021 cm2N_H \lesssim 8\times 10^{21} \ {\rm cm}^{-2}) as non-BMB (neither BAL nor mini-BAL) quasars. Mini-BAL quasars are more similar to non-BMB quasars than to BAL quasars in their distribution of relative X-ray brightness (assessed with Δαox\Delta\alpha_{\rm ox}). Relative colors indicate mild dust reddening in the optical spectra of mini-BAL quasars. Significant correlations between Δαox\Delta\alpha_{\rm ox} and UV absorption properties are confirmed for a sample of 56 sources combining mini-BAL and BAL quasars with high signal-to-noise ratio rest-frame UV spectra, which generally supports models in which X-ray absorption is important in enabling driving of the UV absorption-line wind. We also propose alternative parametrizations of the UV absorption properties of mini-BAL and BAL quasars, which may better describe the broad absorption troughs in some respects.Comment: ApJ accepted; 21 pages, 11 figures, and 9 table

    Near Infrared Spectra and Intrinsic Luminosities of Candidate Type II Quasars at 2 < z < 3.4

    Full text link
    We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II quasars selected from the Sloan Digital Sky Survey, using Triplespec on the Apache Point Observatory 3.5m telescope, FIRE at the Magellan/Baade 6.5m telescope, and GNIRS on Gemini. At redshifts of 2 < z < 3.4, our NIR spectra probe the rest-frame optical region of these targets, which were initially selected to have strong lines of CIV and Ly alpha, with FWHM<2000 km/s from the SDSS pipeline. We use the [OIII]5007 line shape as a model for the narrow line region emission, and find that \halpha\ consistently requires a broad component with FWHMs ranging from 1000 to 7500 km/s. Interestingly, the CIV lines also require broad bases, but with considerably narrower widths of 1000 to 4500 km/s. Estimating the extinction using the Balmer decrement and also the relationship in lower-z quasars between rest equivalent width and luminosity in the [OIII] line, we find typical A_V values of 0-2 mag, which naturally explain the attenuated CIV lines relative to Halpha. We propose that our targets are moderately obscured quasars. We also describe one unusual object with three distinct velocity peaks in its [OIII] spectrum.Comment: Accepted for publication in ApJ, 18 pages, 14 figure

    Evidence for a Two-stage Melting Transition of the Vortex Matter in Bi2Sr2Ca1Cu2O8+d Single Crystals obtained by Muon Spin Rotation

    Full text link
    From muon spin rotation measurements on under- to overdoped Bi-2212 crystals we obtain evidence for a two-stage transition of the vortex matter as a function of temperature. The first transition is well known and related to the irreversibility line (IL). The second one is located below the IL and has not been previously observed. It occurs for all three sets of crystals and is unrelated to the vortex mobility. Our data are consistent with a two-stage melting scenario where the intra-planar melting of the vortex lattice and the inter-planar decoupling of the vortex lines occur independently.Comment: 9 pages and 3 figure

    Candidate Type II Quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III

    Full text link
    At low redshifts, dust-obscured quasars often have strong yet narrow permitted lines in the rest-frame optical and ultraviolet, excited by the central active nucleus, earning the designation Type II quasars. We present a sample of 145 candidate Type II quasars at redshifts between 2 and 4.3, encompassing the epoch at which quasar activity peaked in the universe. These objects, selected from the quasar sample of the Baryon Oscillation Spectroscopic Survey of the Sloan Digital Sky Survey III, are characterized by weak continuum in the rest-frame ultraviolet (typical continuum magnitude of i \approx 22) and strong lines of CIV and Ly \alpha, with Full Width at Half Maximum less than 2000 kms-1. The continuum magnitudes correspond to an absolute magnitude of -23 or brighter at redshift 3, too bright to be due exclusively to the host galaxies of these objects. Roughly one third of the objects are detected in the shorter-wavelength bands of the WISE survey; the spectral energy distributions (SEDs) of these objects appear to be intermediate between classic Type I and Type II quasars seen at lower redshift. Five objects are detected at rest frame 6\mu m by Spitzer, implying bolometric luminosities of several times 10^46 erg s-1. We have obtained polarization measurements for two objects; they are roughly 3% polarized. We suggest that these objects are luminous quasars, with modest dust extinction (A_V ~ 0.5 mag), whose ultraviolet continuum also includes a substantial scattering contribution. Alternatively, the line of sight to the central engines of these objects may be partially obscured by optically thick material.Comment: 26 pages, 13 figures, 10 tables, 4 machine readable tables. Accepted for publication in MNRA

    X-ray Sources in the Hubble Deep Field Detected by Chandra

    Full text link
    We present first results from an X-ray study of the Hubble Deep Field North (HDF-N) and its environs obtained using 166 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. This is the deepest X-ray observation ever reported, and in the HDF-N itself we detect six X-ray sources down to a 0.5--8 keV flux limit of 4E-16 erg cm^-2 s^-1. Comparing these sources with objects seen in multiwavelength HDF-N studies shows positional coincidences with the extremely red object NICMOS J123651.74 +621221.4, an active galactic nucleus (AGN), three elliptical galaxies, and one nearby spiral galaxy. The X-ray emission from the ellipticals is consistent with that expected from a hot interstellar medium, and the spiral galaxy emission may arise from a `super-Eddington' X-ray binary or ultraluminous supernova remnant. Four of the X-ray sources have been detected at radio wavelengths. We also place X-ray upper limits on AGN candidates found in the HDF-N, and we present the tightest constraints yet on X-ray emission from the SCUBA submillimeter source population. None of the 10 high-significance submillimeter sources reported in the HDF-N and its vicinity is detected with Chandra ACIS. These sources appear to be dominated by star formation or have AGN with Compton-thick tori and little circumnuclear X-ray scattering.Comment: 11 pages, ApJ, in press, also available from http://www.astro.psu.edu/users/niel/hdf/hdf-chandra.htm

    The Chandra Deep Field North Survey. IX. Extended X-ray Sources

    Full text link
    The ~1 Ms Chandra Deep Field North observation is used to study the extended X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N), yielding the most sensitive probe of extended X-ray emission at cosmological distances to date. A total of six such sources are detected, the majority of which align with small numbers of optically bright galaxies. Their angular sizes, band ratios, and X-ray luminosities -- assuming they lie at the same distances as the galaxies coincident with the X-ray emission -- are generally consistent with the properties found for nearby groups of galaxies. One source is notably different and is likely to be a poor-to-moderate X-ray cluster at high redshift (i.e., z > 0.7). We are also able to place strong constraints on the optically detected cluster of galaxies ClG 1236+6215 at z=0.85 and the wide-angle-tail radio galaxy VLA J123725.7+621128 at z~1-2. With rest-frame 0.5--2.0 keV X-ray luminosities of <(3-15)e42 ergs s^{-1}, the environments of both sources are either likely to have a significant deficit of hot intra-cluster gas compared to local clusters of galaxies, or they are X-ray groups. We find the surface density of extended X-ray sources in this observation to be 167 (+97,-67) deg^{-2} at a limiting soft-band flux of approximately 3e-16 ergs s^{-1} cm^{-2}. No evolution in the X-ray luminosity function of clusters is needed to explain this value. (Abridged)Comment: 16 pages, 14 figures (8 color), LaTeX emulateapj5.sty, accepted for publication by the Astronomical Journal. Manuscript with full resolution embedded images available at http://www.astro.psu.edu/users/niel/hdf/hdf-chandra.htm
    corecore