Stefan Collier

A new direct method for measuring the Hubble constant from reverberating accretion discs in active galaxies (2007)

Stefan Collier, Keith Horne, Bradley M. Peterson

We show how wavelength-dependent time delays between continuum flux variations of AGN can be used to test the standard black hole-accretion disc paradigm, by measuring the temperature structure T (R)...

Intensive HST, RXTE and ASCA Monitoring of NGC 3516: Evidence Against Thermal Reprocessing (1999)

Edelson, Rick, Koratkar, Anuradha, Nandra, Kirpal, Goad, Michael, Peterson, Bradley M., Collier, Stefan, ...

During 1998 April 13-16, NGC 3516 was monitored almost continuously with HST for 10.3 hr in the UV and 2.8 d in the optical, and simultaneous RXTE and ASCA monitoring covered the same period. The...

A new direct method for measuring the Hubble constant from reverberating accretion discs in active galaxies (1998)

Collier, Stefan, Horne, Kieth, Wanders, Ignaz, Peterson, Bradley M.

We show how wavelength-dependent time delays between continuum flux variations of AGN can be used to test the standard black hole-accretion disc paradigm, by measuring the temperature structure...

On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei (1998)

Peterson, Bradley M., Wanders, Ignaz, Horne, Keith, Collier, Stefan, Alexander, Tal, Kaspi, Shai, ...

We describe a model-independent method of assessing the uncertainties in cross-correlation lags determined from AGN light curves, and use this method to investigate the reality of lags between UV and...