Mid Infrared Spectra of Radio Galaxies and Quasars

Spitzer Infrared Spectrograph (IRS) observations of 3C radio galaxies and quasars shed new light on the nature of the central engines of AGN. Emission from silicate dust obscuring the central engine can be used to estimate the bolometric luminosity of an AGN. Emission lines from ions such as O IV and Ne V give another indication of the presence or lack of a hidden source of far-UV photons in the nucleus. Radio-loud AGN with relative-to-Eddington luminosity ratios of L/L_Edd < 3E-3 do not appear to have broad optical emission lines, though some do have strong silicate emission. Aromatic emission features from star formation activity are common in low-luminosity radio galaxies. Strong molecular hydrogen pure-rotational emission lines are also seen in some mid-IR weak radio galaxies, caused by either merger shocks or jet shocks in the interstellar medium.Comment: Conference proceedings to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP

Managerial Organization of U.S. Farms: Importance for Classifying Farms and Evaluating the Distribution of Farm Payments

A new typology of U.S. farms is constructed focusing on the managerial organization of farms. Single operator farms are distinguished from those with multiple operators which are divided into four classes: (single generation farms with 1) operators of the same sex, 2) operators of opposite sex, and multiple generation farms with 3) an elder primary operator, and 4) an younger primary operator). The utility of this classification scheme for understanding farm structure is analyzed and findings show that the managerial organization represents an important classification for understanding the distribution of farm payments.Farm Household, Government Policy, Agricultural and Food Policy,

Jet-ISM Interaction in the Radio Galaxy 3C293: Jet-driven Shocks Heat ISM to Power X-ray and Molecular H2 emission

We present a 70ks Chandra observation of the radio galaxy 3C293. This galaxy belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have very luminous emission from warm molecular hydrogen. In radio galaxies, the molecular gas appears to be heated by jet-driven shocks, but exactly how this mechanism works is still poorly understood. With Chandra, we observe X-ray emission from the jets within the host galaxy and along the 100 kpc radio jets. We model the X-ray spectra of the nucleus, the inner jets, and the X-ray features along the extended radio jets. Both the nucleus and the inner jets show evidence of 10^7 K shock-heated gas. The kinetic power of the jets is more than sufficient to heat the X-ray emitting gas within the host galaxy. The thermal X-ray and warm H2 luminosities of 3C293 are similar, indicating similar masses of X-ray hot gas and warm molecular gas. This is consistent with a picture where both derive from a multiphase, shocked interstellar medium (ISM). We find that radio-loud MOHEGs that are not brightest cluster galaxies (BCGs), like 3C293, typically have LH2/LX~1 and MH2/MX~1, whereas MOHEGs that are BCGs have LH2/LX~0.01 and MH2/MX~0.01. The more massive, virialized, hot atmosphere in BCGs overwhelms any direct X-ray emission from current jet-ISM interaction. On the other hand, LH2/LX~1 in the Spiderweb BCG at z=2, which resides in an unvirialized protocluster and hosts a powerful radio source. Over time, jet-ISM interaction may contribute to the establishment of a hot atmosphere in BCGs and other massive elliptical galaxies.Comment: Accepted by ApJ 21 pages in ApJ format, 9 figures, 8 table