63 citations · 172 across the 15 of their papers we have counts for
15 papers · 1 filter
The HRX-BL Lac sample - evolution of BL Lac objects
V. Beckmann, D. Engels, N. Bade +1
The unification of X-ray and radio selected BL Lacs has been an outstanding problem in the blazar research in the past years. Recent investigations have shown that the gap between…
The Hamburg/ESO survey for bright QSOs. III. A large flux-limited sample of QSOs
L. Wisotzki, N. Christlieb, N. Bade +4
We present a new sample of 415 bright QSOs and Seyfert~1 nuclei drawn from the Hamburg/ESO survey (HES). The sample is spectroscopically 99 % complete and well-defined in terms of…
The extreme high frequency peaked BL Lac 1517+656
Volker Beckmann, Norbert Bade, Olaf Wucknitz
We present optical spectroscopy data that allowed a measurement of the redshift for the X-ray selected BL Lacertae object 1517+656. With a redshift of z = 0.702 this object has an…
X-ray luminous radio-quiet high redshift QSOs in the ROSAT All-Sky Survey
Xue-Bing Wu, Norbert Bade, Volker Beckmann
X-ray luminous radio-quiet high redshift QSOs are rare and can be used for the investigation of several important astronomical questions. We have conducted a large area survey for…
The giant X-ray outbursts in NGC 5905 and IC 3599: Follow-up observations and outburst scenarios
Stefanie Komossa, Norbert Bade
(abridged) Huge amplitude X-ray outbursts in a few galaxies were reported in the last few years. As one of the exciting possibilities to explain these observations, tidal disruptio…
The giant X-ray outburst in NGC 5905 - a tidal disruption event ?
Stefanie Komossa, Norbert Bade
NGC 5905 is one of the very few galaxies that underwent a giant X-ray outburst, with a change in ROSAT photon countrate of a factor ~100. The outburst spectrum is both, very soft a…