reaking the Degeneracy in Magnetic Cataclysmic Variable X-Ray Spectral Modeling Using X-Ray Light Curve

Author(s):Show less -

Belloni, Diogo ^{[1, 2]} ; Rodrigues, Claudia V. ^[1] ; Schreiber, Matthias R. ^{[2, 3]} ; Castro, Manuel ^[1] ; Costa, Joaquim E. R. ^[1] ; Hayashi, Takayuki ^{[4, 5]} ; Lima, Isabel J. ^[1] ; Luna, Gerardo J. M. ^{[6, 7, 8]} ; Martins, Murilo ^[9] ; Oliveira, Alexandre S. ^[9] ; Parsons, Steven G. ^[10] ; Silva, Karleyne M. G. ^{[11, 12]} ; Stecchini, Paulo E. ^{[1, 13]} ; Stuchi, Teresa J. ^[14] ; Zorotovic, Monica ^[15]

Affiliation:Show less -

^[1] Inst Nacl Pesquisas Espaciais, Av Astronautas 1758, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[2] Univ Tecn Federico Santa Maria, Dept Fis, Av Espana 1680, Valparaiso - Chile

^[3] Millenium Nucl Planet Format NPF, Valparaiso - Chile

^[4] NASA Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 - USA

^[5] Univ Maryland, Baltimore Cty, 1000 Hilltop Circle, Baltimore, MD 21250 - USA

^[6] Univ Buenos Aires, Fac Ciencias Exactas & Nat, Buenos Aires, DF - Argentina

^[7] Univ Buenos Aires, CONICET, Inst Astron Fis Espacio IAFE, Av Inte Guiraldes 2620, C1428ZAA, Buenos Aires, DF - Argentina

^[8] Univ Nacl Hurlingham, Av Gdor Vergara 2222, Buenos Aires, DF - Argentina

^[9] Univ Vale Paraiba, IP&D, BR-12244000 Sao Jose Dos Campos, SP - Brazil

^[10] Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, S Yorkshire - England

^[11] Gemini Observ, Casilla 603, La Serena - Chile

^[12] European Southern Observ, Alonso Cordova 3107, Santiago 19001 - Chile

^[13] Univ Sao Paulo, IAG, Rua Matao 1226, BR-05508900 Sao Paulo, SP - Brazil

^[14] Univ Fed Rio Janeiro, Cidade Univ, BR-21941972 Rio De Janeiro, RJ - Brazil

^[15] Univ Valparaiso, Inst Fsi & Astron, Av Gran Bretana 1111, Valparaiso 2360102 - Chile

• Document type: Journal article
• Source: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES; v. 256, n. 2 OCT 2021.
• Web of Science Citations: 0

Abstract

We present an analysis of mock X-ray spectra and light curves of magnetic cataclysmic variables using an upgraded version of the 3D cyclops code. This 3D representation of the accretion flow allows us to properly model total and partial occultation of the postshock region by the white dwarf as well as the modulation of the X-ray light curves due to the phase-dependent extinction of the preshock region. We carried out detailed postshock region modeling in a four-dimensional parameter space by varying the white dwarf mass and magnetic field strength as well as the magnetosphere radius and the specific accretion rate. To calculate the postshock region temperature and density profiles, we assumed equipartition between ions and electrons; took into account the white dwarf gravitational potential, the finite size of the magnetosphere, and a dipole-like magnetic field geometry; and considered cooling by both bremsstrahlung and cyclotron radiative processes. By investigating the impact of the parameters on the resulting X-ray continuum spectra, we show that there is an inevitable degeneracy in the four-dimensional parameter space investigated here, which compromises X-ray continuum spectral fitting strategies and can lead to incorrect parameter estimates. However, the inclusion of X-ray light curves in different energy ranges can break this degeneracy, and it therefore remains, in principle, possible to use X-ray data to derive fundamental parameters of magnetic cataclysmic variables, which represents an essential step toward understanding their formation and evolution. (AU)

• FAPESP's process: 17/20309-7 - Search and characterization of new magnetic cataclysmic variables
• Grantee: Alexandre Soares de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/26258-4 - Superdense matter in the universe
• Grantee: Manuel Máximo Bastos Malheiro de Oliveira
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/13551-6 - Development of the imaging system of the protoMIRAX experiment and determination of dynamic parameters for the black hole candidate 1E1740.7-2942 through the iron K alfa line
• Grantee: Paulo Eduardo Freire Stecchini
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/05420-1 - Magnetic accretion in cataclysmic variables: SW~Sextantis stars and a search for new objects
• Grantee: Isabel de Jesus Lima
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 15/25972-0 - Development and Characterization of the Detector System of the MIRAX Experiment
• Grantee: Manuel Antonio Castro Ávila
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/14289-3 - Magnetic Cataclysmic variables: secular evolution with the BSE code and emission modelling with the CYCLOPS code
• Grantee: Diogo Teixeira Belloni
• Support Opportunities: Scholarships in Brazil - Post-Doctoral