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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

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Munster Technological University

2004

Galaxies: active

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

A Search For Tev Gamma-Ray Emission From High-Peaked Flat-Spectrum Radio Quasars Using The Whipple Air Cerenkov Telescope, P. T. Reynolds, Et. Al. Oct 2004

A Search For Tev Gamma-Ray Emission From High-Peaked Flat-Spectrum Radio Quasars Using The Whipple Air Cerenkov Telescope, P. T. Reynolds, Et. Al.

Physical Sciences Publications

Blazars have traditionally been separated into two broad categories based on their optical emission characteristics. Blazars with faint or no emission lines are referred to as BL Lacertae objects (BL Lacs), and blazars with prominent, broad emission lines are commonly referred to as flat-spectrum radio quasars (FSRQs). The spectral energy distribution of FSRQs has generally been thought of as being more akin to the low-peaked BL Lacs, which exhibit a peak in the infrared region of the spectrum, as opposed to high-peaked BL Lacs (HBLs), which exhibit a peak in UV/X-ray region of the spectrum. All blazars that are currently …


Xmm-Newton Observations Of The Bl Lac Ms 0205.7+3509: A Dense, Low-Metallicity Absorber, Niall Smith, Et. Al. Apr 2004

Xmm-Newton Observations Of The Bl Lac Ms 0205.7+3509: A Dense, Low-Metallicity Absorber, Niall Smith, Et. Al.

Blackrock Castle Observatory Publications

The high-frequency-peaked BL Lac, MS 0205.7+3509 was observed twice with XMM-Newton. Both X-ray spectra are synchrotron-dominated, with mean 0.2–10 keV fluxes of and  erg cm-2 s-1. The X-ray spectra are well fit by a power-law with absorption above the Galactic value, however no absorption edges are detected, implying a low metallicity absorber () or an absorber with redshift above one (best-fit for an absorber with solar abundances). In either case the absorbing column density must be  cm-2. A new optical spectrum is presented, with a absorption doublet detected at , but no other significant …