Zobrazeno 1 - 10
of 164
pro vyhledávání: '"Verbunt, Frank"'
Autor:
Schrimpf, Andreas, Verbunt, Frank
Near the end of the 16th century Wilhelm IV, Landgraf von Hessen-Kassel, set up an observatory with the main goal to increase the accuracy of stellar positions primarily for use in astrology and for calendar purposes. A new star catalogue was compile
Externí odkaz:
http://arxiv.org/abs/2103.10801
Autor:
Verbunt, Frank, Schrimpf, Andreas
We analyse a manuscript star catalogue by Wilhem IV, Landgraf von Hessen-Kassel, from 1586. From measurements of altitudes and of angles between stars, given in the catalogue, we find that the measurement accuracy averages 26 arcsec for eight fundame
Externí odkaz:
http://arxiv.org/abs/2103.03034
Autor:
Verbunt, Frank, van der Sluys, Marc
In 1717 Halley compared contemporaneous measurements of the latitudes of four stars with earlier measurements by ancient Greek astronomers and by Brahe, and from the differences concluded that these four stars showed proper motion. An analysis with m
Externí odkaz:
http://arxiv.org/abs/1909.13636
Autor:
Verbunt, Frank, Cator, Eric
Publikováno v:
J.Astrophys.Astr. (2017) 38:40
We take a fresh look at the determination of distances and velocities of neutron stars. The conversion of a parallax measurement into a distance, or distance probability distribution, has led to a debate quite similar to the one involving Cepheids, c
Externí odkaz:
http://arxiv.org/abs/1709.07448
We argue that comparison with observations of theoretical models for the velocity distribution of pulsars must be done directly with the observed quantities, i.e. parallax and the two components of proper motion. We develop a formalism to do so, and
Externí odkaz:
http://arxiv.org/abs/1708.08281
The mass distribution of stellar mass black holes can provide important clues to supernova modeling, but observationally it is still ill constrained. Therefore it is of importance to make black hole mass measurements as accurate as possible. The X-ra
Externí odkaz:
http://arxiv.org/abs/1708.08209
Autor:
Verbunt, Frank, Freire, Paulo C. C.
The stellar encounter rate Gamma has been shown to be strongly correlated with the number of X-ray binaries in clusters and also to the number of radio pulsars. However, the pulsar populations in different clusters show remarkably different character
Externí odkaz:
http://arxiv.org/abs/1310.4669
Autor:
Berg, Maureen van den, Verbunt, Frank, Tagliaferri, Gianpiero, Belloni, Tomaso, Bedin, Luigi R., Platais, Imants
We present the first X-ray study of NGC6791, one of the oldest open clusters known (8 Gyr). Our Chandra observation is aimed at uncovering the population of close interacting binaries down to Lx ~ 1e30 erg/s (0.3-7 keV). We detect 86 sources within 8
Externí odkaz:
http://arxiv.org/abs/1301.2331
Autor:
Pinto, Ciro, Ness, Jan-Uwe, Verbunt, Frank, Kaastra, Jelle S., Costantini, Elisa, Detmers, Rob G.
Publikováno v:
A&A 543, A134 (2012)
The X-ray flux of Nova V2491 Cyg reached a maximum some forty days after optical maximum. The X-ray spectrum at that time, obtained with the RGS of XMM-Newton, shows deep, blue-shifted absorption by ions of a wide range of ionization. We show that th
Externí odkaz:
http://arxiv.org/abs/1206.2143
Autor:
Verbunt, Frank, van Gent, Robert H.
In late antiquity and throughout the middle ages, the positions of stars on the celestial sphere were obtained from the star catalogue of Ptolemaios. A catalogue based on new measurements appeared in 1437, with positions by Ulugh Beg, and magnitudes
Externí odkaz:
http://arxiv.org/abs/1206.0628