The X-ray spectra of VW Hydri during the outburst cycle

H. W. Hartmann; P. J. Wheatley; J. Heise; J. A. Mattei; F. Verbunt

Home/Archive/arXiv

arXiv · astro-ph/9908096

The X-ray spectra of VW Hydri during the outburst cycle

H. W. Hartmann·P. J. Wheatley·J. Heise·J. A. Mattei·F. Verbunt

View original source ↗Read source document ↗Export metadata ↓

Abstract

We report six BeppoSAX X-ray observations of VW Hydri during and after the outburst of Sep 23 1998. The outburst flux is lower than the quiescent flux in the entire observed energy band (0.1-10 keV), in agreement with earlier observations. The X-ray spectra are fitted with two-temperature plasma and cooling flow spectral models. These fits show a clear spectral evolution in X-rays for the first time in VW Hydri: the hard X-ray turn-up after the outburst is reflected in the emission measure and the temperature. Moreover, during outburst the 1.5-10 keV flux decreases significantly. We argue that this is not consistent with the constant flux during a ROSAT outburst observation made eight years earlier. We conclude from this observation that there are significant differences between outburst X-ray lightcurves of VW Hydri.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

H. W. Hartmann, P. J. Wheatley, J. Heise, J. A. Mattei, F. Verbunt. 1999-08-09. The X-ray spectra of VW Hydri during the outburst cycle. https://arxiv.org/abs/astro-ph/9908096

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Cosmic Conundrums with Quantum Corrections

Darh energy was discovered over 25 years ago and we do not have an explanation of it. Dark matter comprises 95% of matter in the universe and we still don't know what it is. The Webb telescope has been finding fully formed galaxies with massive black holes millions of times the mass of the sun in the early universe and we don't have any explanation. A quantum density limitation will be used to solve these and other outstanding problems.

astro-ph↗

arXiv2026

On binary pulsars and the force of gravity

The energy-momentum budget of the astrophysical systems can be studied by the exact local conservation equation derived by Landau and Lifshitz. We show that a similar equation is valid for the Einstein-Cartan gravity. We reanalyze a binary pulsar system using the Landau-Lifshitz conservation equation and show that the orbital period change rate can be completely understood as a curvature backreaction process. Taking into account the detailed theoretical and observational research of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. We comment upon the LIGO GW events and their alternative explanation, as well as the recent pulsar timing arrays data.

astro-ph↗

arXiv2026

Oscillation frequencies and mode lifetimes in alpha Centauri A

We analyse our recently-published velocity measurements of alpha Cen A (Butler et al. 2004). After adjusting the weights on a night-by-night basis in order to optimize the window function to minimize sidelobes, we extract 42 oscillation frequencies with l=0 to 3 and measure the large and small frequency separations. We give fitted relations to these frequencies that can be compared with theoretical models and conclude that the observed scatter about these fits is due to the finite lifetimes of the oscillation modes. We estimate the mode lifetimes to be 1-2 d, substantially shorter than in the Sun.

astro-ph↗