2,391 research outputs found
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,
Enhancing Concussion Education and Documentation within Belmont University’s Athletic Department
This doctoral capstone project was completed through a partnership with Belmont University’s Sports Medicine Department. The primary purpose of this project was to identify the department’s current needs and to develop deliverables to enhance and facilitate the concussion education and documents provided to Belmont Athletics stakeholders (including student athletes, university educators, coaching staff, and other members of administration). The process included collaboration with university athletic trainers and student-athletes to ensure usability and creation of relevant products. These resources include informational handouts designed for both student-athletes and educators, an on-field concussion assessment and protocol, concussion education resources with increased opportunities for student interaction, and updated concussion forms. Throughout this experience I had the opportunity to further develop interprofessional communication skills, educate others on the scope of occupational therapy, and gain increased insight into the lived experience of collegiate student-athletes who have experienced concussions
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
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