204 citations · 749 across the 17 of their papers we have counts for
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When teaching: Out with magnitudes, in with monochromatic luminosities!
Frank Verbunt
The goal of this document is to illustrate that teaching the concepts of magnitudes is a needless complication in introductory astronomy courses, and that use of monochromatic lumi…
X-ray and optical observations of M55 and NGC 6366: evidence for primordial binaries
C. G. Bassa, D. Pooley, F. Verbunt +3
We present Chandra X-ray Observatory ACIS-S3 X-ray imaging observations and VLT/FORS2 and Hubble Space Telescope optical observations of two low-density Galactic globular clusters;…
The warm absorber in NGC 5548: The lean years
R. G. Detmers, J. S. Kaastra, E. Costantini +2
We study the variability of the warm absorber and the gas responsible for the emission lines in the Seyfert 1 galaxy NGC 5548, in order to constrain the location and physical prope…
Observational evidence for the origin of X-ray sources in globular clusters
Frank Verbunt, Dave Pooley, Cees Bassa
Low-mass X-ray binaries, recycled pulsars, cataclysmic variables and magnetically active binaries are observed as X-ray sources in globular clusters. We discuss the classification…
High-resolution X-ray spectroscopy of the Narrow line Seyfert 1 galaxy NGC 4051 with Chandra LETGS
M. Fenovcik, J. S. Kaastra, E. Costantini +2
We study the absorption and emission properties of the photoionised gas near one of the brightest and most variable AGN, the Seyfert galaxy NGC 4051, in order to constrain the geom…
Evidence for precession of the isolated neutron star RX J0720.4-3125
F. Haberl, R. Turolla, C. P. De Vries +4
The XMM-Newton spectra of the isolated neutron star RX J0720.4-3125 obtained over 4.5 years can be described by sinusoidal variations in the inferred blackbody temperature, the siz…