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Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. III - Further observations of NGC 5548 at optical wavelengths

Peterson, B. M.; Alloin, D.; Axon, D.; Balonek, T. J.; Bertram, R.; Boroson, T. A.; Christensen, J. A.; Clements, S. D.; Dietrich, M.; Elvis, Martin S.; Filippenko, A. V.; Gaskell, C. M.; Haswell, C. A.; Huchra, J; Jackson, N.; Kollatschny, W.; Korista, K. T.; Lame, N. J.; Leacock, R. J.; Lin, S.-N.; Malkan, M. A.; Monk, A. S.; Penston, M. V.; Pogge, R. W.; Robinson, A.; Rosenblatt, E. I.; Shields, J. C.; Smith, A. G.; Stirpe, G. M.; Sun, W.-H.; Turner, T. J.; Wagner, R. M.; Wilkes, Belinda Jane; Wills, B. J. (IOP Publishing, 1992)

The results of the second year of an intensive ground-based spectroscopic and photometric study of variability in the bright Seyfert 1 galaxy NGC 5548 are reported in order to study the relationship between continuum and ...

EXOSAT X-ray spectra of quasars

Comastri, Andrea; Setti, Giancarlo; Zamorani, Giovanni; Elvis, Martin; Wilkes, Belinda Jane; McDowell, Jonathan Christopher; Giommi, Paolo (IOP Publishing, 1992)

Measurements of the X-ray spectra in the 0.1-10-keV energy range for 17 AGN (mostly PG quasars) using the Exosat Low and Medium Energy arrays are presented. For each object, the best-fit spectral parameters in the medium-energy ...

X-ray absorption toward the red quasar 3C 212

Elvis, Martin S.; Fiore, Fabrizio; Mathur, Smita; Wilkes, Belinda Jane (IOP Publishing, 1994)

A Roentgen Satellite (ROSAT) X-ray spectrum of the z = 1.049 'red quasar' 3C 212 has a strong low-energy cutoff. The spectrum can be fitted with a power law (of energy index 1.4(+0.8, -0.6) with low-energy photoelectric ...

Multifrequency observations of KAZ 102 during the ROSAT all-sky survey

Treves, A.; Fink, H. H.; Malkan, M.; Wagner, S. J.; Wilkes, Belinda Jane; Baganoff, F.; Heidt, J.; Pian, E.; Sadun, A.; Schaeidt, S.; Bonnell, J. T.; Brinkmann, W.; de Martino, D.; Maraschi, L.; Tanzi, E. G.; Ulrich, M. H.; Wamsteker, W. (IOP Publishing, 1995)

The bright quasar Kaz 102, which lies in the vicinity of the North Ecliptic Pole, was monitored during the ROSAT All Sky Survey for 121.5 days from 1990 July 30 to 1991 January 25. In the course of the survey, optical ...

Absorption in X-ray spectra of high-redshift quasars

Elvis, Martin S.; Fiore, Fabrizio; Wilkes, Belinda Jane; McDowell, Jonathan Christopher; Bechtold, Jill (IOP Publishing, 1994)

We present evidence that X-ray absorption is common in high-redshift quasars. We have studied six high-redshift (z approximately 3) quasars with the ROSAT Position Sensitive Proportional Counter (PSPC) of which four are ...

The ROSAT spectrum of 3C 351 - A warm absorber in an X-ray-'quiet' quasar?

Fiore, Fabrizio; Elvis, Martin S.; Mathur, Smita; Wilkes, Belinda Jane; McDowell, Jonathan Christopher (IOP Publishing, 1993)

3C 351 is one of the most X-ray-quiet radio quasars (alpha(ox) about 1.6). We have observed 3C 351 with the ROSAT position sensitive proportional counter (PSPC) and find a complex X-ray spectrum which is not well reproduced ...

The complex optical to soft x-ray spectrum of the low-redshift radio-quiet quasars

Fiore, Fabrizio; Elvis, Martin S.; McDowell, Jonathan Christopher; Siemiginowska, Aneta L.; Wilkes, Belinda Jane (IOP Publishing, 1994)

Eight high signal-to-noise ROSAT Position Sensitive Proportional Counter (PSPC) observations of six low-redshift (o.048 less than z less than 0.155) radio-quiet quasars have been analyzed to study ant soft excess. All the ...

Consistency of spherical, gravity-dominated dynamics with quasar high-ionization emission-line profiles

Kallman, T. R.; Wilkes, Belinda Jane; Krolik, J. H.; Green, Richard (IOP Publishing, 1993)

Line profile data are used to test a simple kinematic model - spherically symmetric gravitational free fall - in which the number of free parameters is limited by requiring physical self-consistency. The predictions of ...

PKS 0483-436 - A high-redshift quasar with strong X-ray absorption

Wilkes, Belinda Jane; Elvis, Martin S.; Fiore, Fabrizio; McDowell, Jonathan Christopher; Tananbaum, Harvey D.; Lawrence, Andrew (IOP Publishing, 1992)

The first X-ray spectrum of a high-redshift (z = 2.85) quasar is reported. The Rosat PSPC spectrum of PKS 0438-436, covering 0.3-9 keV in the quasar's rest frame, reveals unexpected absorption of about 1 x 10 exp 22/sq cm, ...

Infrared to x-ray spectral energy distributions of high redshift quasars

Bechtold, Jill; Elvis, Martin S.; Fiore, Fabrizio; Kuhn, Olga; Cutri, Roc M.; McDowell, Jonathan Christopher; Rieke, Marcia; Siemiginowska, Aneta L.; Wilkes, Belinda Jane (IOP Publishing, 1994)

We have observed 14 quasars with z greater than 2.8 with the ROSAT-PSPC, and detected 12 of them, including the z=4.11 quasar 0000-263. We present the first x-ray spectrum of a radio quiet quasar with z greater than 3, ...