Physical Sciences and Mathematics Commons^™

Results Of Webt, Vlba And Rxte Monitoring Of 3c 279 During 2006-2007, Niall Smith, Et. Al.

Blackrock Castle Observatory Publications

Context. The quasar 3C 279 is among the most extreme blazars in terms of luminosity and variability of flux at all wavebands. Its variations in flux and polarization are quite complex and therefore require intensive monitoring observations at multiple wavebands to characterise and interpret the observed changes.

Aims. In this paper, we present radio-to-optical data taken by the WEBT, supplemented by our VLBA and RXTE observations, of 3C 279. Our goal is to use this extensive database to draw inferences regarding the physics of the relativistic jet.

Methods. We assemble multifrequency light curves with data from 30 ground-based observatories and …

Galaxy And Mass Assembly (Gama): The Effect Of Galaxy Group Environment On Active Galactic Nuclei, Yjan A. Gordon, Kevin A. Pimbblet, Matt S. Owers, Joss Bland-Hawthorn, Sarah Brough, Michael J.I. Brown, Michelle E. Cluver, Scott M. Croom, Benne W. Holwerda, Jonathan Loveday, Smriti Mahajan, Lingyu Wang

Faculty Scholarship

In galaxy clusters, efficiently accreting active galactic nuclei (AGNs) are preferentially located in the infall regions of the cluster projected phase-space, and are rarely found in the cluster core. This has been attributed to both an increase in triggering opportunities for infalling galaxies, and a reduction of those mechanisms in the hot, virialized, cluster core. Exploiting the depth and completeness (98 per cent at r < 19.8mag) of the Galaxy And Mass Assembly survey (GAMA), we probe down the group halo mass function to assess whether AGNs are found in the same regions in groups as they are in clusters. We select 451 optical AGNs from 7498 galaxies with log10(M*/M⊙) > 9.9 in 695 groups with 11.53 ≤ log10(M200/M⊙) ≤ 14.56 at < 0.15. By analysing the projected phase-space positions of these galaxies, we demonstrate that when split both radially, and into physically derived infalling and core populations, AGN position within group projected phase-space is dependent on halo mass. For groups with log10(M200/M⊙) > 13.5,AGNs are preferentially found in the infalling galaxy populationwith 3.6s confidence. At lower halo masses, we observe no difference in AGN fraction between core …

Multiwavelength Observations Of The Blazar Bl Lacertae: A New Fast Tev Gamma-Ray Flare, P. T. Reynolds, Et Al

Physical Sciences Publications

Combined with measurements made by very-long-baseline interferometry, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and only within the last few years have these flares been observed from lower-frequency-peaked BL Lac objects and flat-spectrum radio quasars. We report on a fast TeV gamma-ray flare from the blazar BL Lacertae observed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS). with a rise time of ~2.3 hr and a decay time of ~36 min. The peak flux above 200 GeV …