Application of the hot white dwarf atmosphere models to the X-ray data of classical novae

Date

1998-09-10

Author

Balman, Şölen

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

174
views

0
downloads

The analyses of X-ray emission from classical novae after outburst have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple black body model of emission. Thus, the ROSAT Position Sensitive Proportional Counter (PSPC) data (0.1-2.4 keV) of the classical novae V1974 Cygni 1992 and some others have been reanalyzed in order to understand the spectral development of novae in the X-ray wavelengths during the outburst stage together with the effect of the enhanced metal abundances in the white Dwarf (WD) atmosphere prior to the outburst. The X-ray spectrum of V1974 Cygni 1992 is fit with a hot white dwarf atmosphere emission model developed for the remnants of classical novae near the Eddington luminosity and a thermal plasma emission model to account for the harder Xray tail in the spectrum of the nova. The post-outburst X-ray spectrum of the remnant white dwarf is examined in the context of evolution on the Hertzsprung-Russell diagram using an O-Ne and a C-O enhanced atmosphere emission model. A constant bolometric luminosity evolution is detected for the first time for a classical nova with increasing effective temperature and decreasing photospheric radius using the O-Ne enhanced model. A peak effective temperature of 51 eV (5.9x10(5) K) is detected at day 511 after outburst. The light curve of the hard X-ray component is found to be independent from the soft one. The maximum of the hard X-ray emission is reached at day similar to 150 after the outburst. The time evolution of the hard X-ray flux and the plasma temperatures decreasing from 10 keV to 1 keV suggest emission from shock heated gas as the origin of the hard X-ray component.

Subject Keywords

Spectral evolution, Emission, Cygni-1992, Outbursts, Accretion, Winds

URI

https://hdl.handle.net/11511/53876

Collections

Department of Physics, Conference / Seminar

Suggestions

OpenMETU
Core

The re-analysis of the ROSAT data of Nova Mus 1983 using white dwarf atmosphere emission models Balman, Şölen; Krautter, J (2001-10-01) The analyses of X-ray emission from classical novae during the outburst stage have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple blackbody model of emission. Thus, ROSAT Position Sensitive Proportional Counter (PSPC) archival data of the classical Nova Mus 1983 (GQ Mus) have been re-analysed in order to understand the spectral development in the X-ray wavelengths during the outburst stage. The X-ray spec...
Assessment and modelling of particle clustering in cast aluminum matrix composites Çetin, Arda; Kalkanlı, Ali; Department of Metallurgical and Materials Engineering (2008) The damage and deformation behaviour of particle reinforced aluminum matrix composites can be highly sensitive to local variations in spatial distribution of reinforcement particles, which markedly depend on melt processing and solidification stages during production. The present study is aimed at understanding the mechanisms responsible for clustering of SiC particles in an Al-Si-Mg (A356) alloy composite during solidification process and establishing a model to predict the risk of cluster formation as a f...
SENSITIVITY OF THE ASYMMETRY OF THE POLARIZED B-QUARK RADIATIVE B-]S-GAMMA-G DECAY TO THE MODEL FCNC Alıyev, Tahmasıb; PAK, NK; REKALO, MP (1995-01-26) The effects induced by the initial b-quark longitudinal polarization in the rare b-->s gamma g decay in the standard (SM) and two Higgs doublet (2HDM) models are investigated. Using the structure functions formalism we calculate different asymmetries in b-->s gamma g decay in terms of the magnetic dipole type form factors, which describe the b-->s gamma and b-->sg transitions. It is shown that the general expressions for the structure functions are model independent; the model dependent information is conta...
Determination of optical parameters of Ga0.75In0.25Se layered crystals IŞIK, MEHMET; Hasanlı, Nızamı (2012-05-01) The optical properties of the Ga0.75In0.25Se crystals have been investigated by means of transmission and reflection measurements in the wavelength range of 380-1100 nm. The analysis of the results performed at room temperature revealed the presence of optical indirect transtions with band gap energy of 1.89 eV. The variation of the band gap energy as a function of temperature was also studied in the temperature range of 10-300 K. The rate of change of band gap energy (? = 6.2 x 10(4) eV/K) and absolute zer...
Theoretical and experimental investigation of bulk glass forming ability in bulk amorphous alloy systems Ayas, Can; Mekrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2005) In this study molecular dynamics simulation program in NVT ensemble using Velocity Verlet integration was written in order to investigate the glass forming ability of two metallic systems. The Zn-Mg system, one of the frontiers of simple metal-metal metallic glasses and Fe-B, inquiring attention due to presence of many bulk glass forming alloy systems evolved from this binary with different alloying element additions. In addition to this, atomistic calculations on the basis of ordering were carried out for ...

Citation Formats

Ş. Balman, “Application of the hot white dwarf atmosphere models to the X-ray data of classical novae,” 1998, vol. 544, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/53876.