Evaluation of Ball Bearing Separator Materials Operating Submerged in Liquid Nitrogen

Wilson, W. A.; Martin, K. B.; Brennan, J. Keirn; Birmingham, B. W.

doi:10.1080/05698196108972419

Cited by 12 publications

(6 citation statements)

References 3 publications

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“…The rms noise of the maps is ∼1-1.3 mJy beam −1 , and the synthesized beam is ∼25 ′′ . The results of the survey are presented in de Bruyn & Wilson (1976, 1978, Meurs & Wilson (1981, 1984, and Wilson & Meurs (1982). Most of the objects are relatively distant, with < D > ≈ 250 Mpc, and those which were detected have typical powers of P 20 cm ≈ 10 21 − 10 24 W Hz −1 .…”

Section: The Westerbork Surveysmentioning

confidence: 99%

Radio Continuum Survey of an Optically Selected Sample of Nearby Seyfert Galaxies

Ho¹,

Ulvestad²

2001

ASTROPHYS J SUPPL S

284

392

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We have used the Very Large Array (VLA) to conduct a survey for radio continuum emission in the sample of 52 Seyfert nuclei selected from the optical spectroscopic galaxy catalog of Ho, Filippenko, and Sargent. This Seyfert sample is the most complete and least biased available, and, as such, it will be useful for a variety of statistical analyses. Here we present the observations, measurements, and an atlas of radio maps.The observations were made at 6 cm in the B-array and at 20 cm in the A-array, yielding matched angular resolutions of ∼1 ′′ . We detected 44 objects (85%) at 6 cm and 37 objects (71%) at 20 cm above a 3 σ threshold of 0.12 mJy beam −1 . The sources have a wide range of radio powers (P ≈ 10 18 -10 25 W Hz −1 ), spectral indices (α 20 6 ≈ +0.5 to -1), and linear sizes (L ≈ few tens pc -15 kpc). The morphology of the radio emission is predominantly that of a compact core, either unresolved or slightly resolved, occasionally accompanied by elongated, jet-like features. Linearly-polarized emission was detected at 6 cm in 12 sources, 9 of which were also detected at 20 cm.

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Section: The Westerbork Surveysmentioning

confidence: 99%

Radio Continuum Survey of an Optically Selected Sample of Nearby Seyfert Galaxies

Ho¹,

Ulvestad²

2001

ASTROPHYS J SUPPL S

284

392

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“…According to estimates, the total radio emission of Seyfert galaxies includes at least a ∼20% contribution from the disk of the underlying galaxy. We take the total fluxes F T of detected Seyfert galaxies from Wright (1974), Wilson & Meurs (1982), Gioia et al (1983), Tovmassian et al (1984), Ulvestad & Wilson (1984a,b), Unger et al (1986Unger et al ( , 1987, Harnett (1987), Burns et al (1987), , Condon (1987), Antonucci & Barvainis (1988), Ulvestad & Wilson (1989), Kellermann et al (1989), Unger et al (1989), Condon et al (1990), Condon & Broderick (1991), Klein, Weiland & Brinks (1991), Gregory & Condon (1991), van Driel, van den Broek & de Jong (1991), Neff & Hutchings (1992), White & Becker (1992), Cram, North & Savage (1992), Miller, Rawlings & Saunders (1993), Vader et al (1993, Slee et al (1994), Gregorini et al (1994), Bicay et al (1995). We converted the fluxes measured at different frequencies (mostly at ∼1.4 GHz and ∼5 GHz) to 2.3 GHz with the adoption of a spectral index n = −0.7.…”

Section: Radio Cores and Extended Radio Emissionmentioning

confidence: 99%

Compact Radio Cores and Nuclear Activity in Seyfert Galaxies

Giuricin¹,

Fadda²,

Mezzetti

1996

ApJ

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Using recent high-resolution (<0.1") radio observations of a large sample of Seyfert galaxies (Roy et al., 1994), we analyze the relations between their compact radio core emission and several nuclear and host galaxy properties (galaxy morphology, optical, infrared, X-ray, extended radio emissions, interaction parameters, and some emission line properties). We apply survival analysis techniques in order to exploit the information contained in the numerous "censored" data (upper limits on fluxes).We find that Seyfert nuclei hosted in early-type galaxies are, on average, characterized by stronger radio core emission than the norm for Seyfert galaxies. Galaxies with a nearby companion display enhanced radio core emission with respect to objects without companions. Furthermore, we confirm that Seyfert types 2 host more powerful compact radio cores than types 1.Remarkably, radio core emission appears to be unrelated to optical, near-infrared, and far-infrared radiations, but shows some correlation with total radio emission and with tracers of nuclear activity such as the IRAS 12 and 25 µm band, hard X-ray and narrow-line emissions. This favours the view that Seyfert radio cores are typically powered by AGN rather than by radio supernovae.A link between radio core strength and bolometric luminosity is suggested, in analogy to what is observed in the cores of radio-quiet QSOs.

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“…Early radio surveys (de Bruyn & Wilson 1976;Meurs & Wilson 1981;Wilson & Meurs 1982) of Seyferts with the Westerbork Synthesis Radio Telescope demonstrated that, in most Seyferts, most of the radio flux is confined to the central region of the galaxy. Large radio structures analogous to jets in radio galaxies were not generally detected and most of the detected objects were unresolved at this resolution (∼20 ′′ ).…”

Section: Introductionmentioning

confidence: 99%

Large-Scale Outflows in Edge-on Seyfert Galaxies. II. Kiloparsec-Scale Radio Continuum Emission

Colbert¹,

Baum²,

Gallimore³

et al. 1996

ApJ

107

130

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We present deep images of the kpc-scale radio continuum emission in 14 edge-on galaxies (ten Seyfert and four starburst galaxies). Observations were taken with the VLA at 4.9 GHz (6 cm). The Seyfert galaxies were selected from a distance-limited sample of 22 objects (defined in paper I). The starburst galaxies were selected to be well-matched to the Seyferts in radio power, recessional velocity and inclination angle. All four starburst galaxies have a very bright disk component and one (NGC 3044) has a radio halo that extends several kpc out of the galaxy plane. Six of the ten Seyferts observed have large-scale (radial extent ∼ >1 kpc) radio structures extending outward from the nuclear region, indicating that large-scale outflows are quite common in Seyferts.Large-scale radio sources in Seyferts are similar in radio power and radial extent to radio halos in edge-on starburst galaxies, but their morphologies do not resemble spherical halos observed in starburst galaxies. The sources have diffuse morphologies, but, in general, they are oriented at skewed angles with respect to the galaxy minor axes. This result is most easily understood if the outflows are AGN-driven jets that are somehow diverted away from the galaxy disk on scales ∼ >1 kpc. Starburst-driven winds, however, cannot be ruled out. More observational work is needed to determine whether massive star formation is present at high enough rates to drive galactic winds out to kpc scales in Seyfert galaxies.

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Evaluation of Ball Bearing Separator Materials Operating Submerged in Liquid Nitrogen

Cited by 12 publications

References 3 publications

Radio Continuum Survey of an Optically Selected Sample of Nearby Seyfert Galaxies

Radio Continuum Survey of an Optically Selected Sample of Nearby Seyfert Galaxies

Compact Radio Cores and Nuclear Activity in Seyfert Galaxies

Large-Scale Outflows in Edge-on Seyfert Galaxies. II. Kiloparsec-Scale Radio Continuum Emission

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