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Full-Text Articles in Physical Sciences and Mathematics
Broad Lyα Emission From Three Nearby Bl Lacertae Objects, John T. Stocke, Charles W. Danforth, Eric S. Perlman
Broad Lyα Emission From Three Nearby Bl Lacertae Objects, John T. Stocke, Charles W. Danforth, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present far-UV HST/COS spectra of four nearby BLLac objects. BLLac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lyα emission in HST/COS spectra of Mrk421 (z = 0.030) and PKS2005-489 (z = 0.071) as well as an archival HST/GHRS observation of Mrk501 (z = 0.0337). Archival HST/STIS observations of PKS2155-304 (z = 0.116) show no Lyα emission to a very low upper limit. Using the assumption that the broad-line region …
The Deep X-Ray Radio Blazar Survey. Iii. Radio Number Counts, Evolutionary Properties, And Luminosity Function Of Blazars, Paolo Padovani, Paolo Giommi, Hermine Landt, Eric S. Perlman
The Deep X-Ray Radio Blazar Survey. Iii. Radio Number Counts, Evolutionary Properties, And Luminosity Function Of Blazars, Paolo Padovani, Paolo Giommi, Hermine Landt, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
Our knowledge of the blazar surface densities and luminosity functions, which are fundamental parameters, relies still on samples at relatively high flux limits. As a result, our understanding of this rare class of active galactic nuclei is mostly based on relatively bright and intrinsically luminous sources. We present the radio number counts, evolutionary properties, and luminosity functions of the faintest blazar sample with basically complete (∼95%) identifications. Based on the Deep X-Ray Radio Blazar Survey (DXRBS), it includes 129 flat-spectrum radio quasars ( FSRQs) and 24 BL Lac objects down to a 5 GHz flux and power ∼50 mJy and …
Broadband Optical Observations Of Bl Lacertae During The 1997 Outburst, Terry D. Oswalt, Daniel Marshall, Tim Robishaw
Broadband Optical Observations Of Bl Lacertae During The 1997 Outburst, Terry D. Oswalt, Daniel Marshall, Tim Robishaw
Aerospace, Physics, and Space Science Faculty Publications
We present BVRI observations of BL Lacertae during its recent outburst. These observations, made during a 3 month period, cover a significant portion of the optical flare. The reduced data are displayed as light curves and broadband spectra. Changes in the spectral index are analyzed, and the results are compared with previous BL Lac observations. We find that the variations are simultaneous in the optical bands, but the higher frequency bands show a higher amplitude of variability. The spectral index is variable during the active period, and there is marginal evidence that the spectrum flattens as the source gets brighter.