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Unambiguous Detection of Reflection in Magnetic Cataclysmic Variables: Joint NuSTAR–XMM-Newton Observations of Three Intermediate Polars

Mukai, K. and Rana, V. and Bernardini, F. and de Martino, D. (2015) Unambiguous Detection of Reflection in Magnetic Cataclysmic Variables: Joint NuSTAR–XMM-Newton Observations of Three Intermediate Polars. Astrophysical Journal Letters, 807 (2). Art. No. L30. ISSN 2041-8205. doi:10.1088/2041-8205/807/2/L30.

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In magnetic cataclysmic variables (CVs), X-ray emission regions are located close to the white dwarf surface, which is expected to reflect a significant fraction of intrinsic X-rays above 10 keV, producing a Compton reflection hump. However, up to now, a secure detection of this effect in magnetic CVs has largely proved elusive because of the limited sensitivity of non-imaging X-ray detectors. Here we report our analysis of joint NuSTAR–XMM-Newton observations of three magnetic CVs, V709 Cas, NY Lup, and V1223 Sgr. The improved hard X-ray sensitivity of the imaging NuSTAR data has resulted in the first robust detection of Compton hump in all three objects, with amplitudes of ~1 or greater in NY Lup, and likely <1.0 in the other two. We also confirm earlier reports of a strong spin modulation above 10 keV in V709 Cas, and we report the first detection of small spin amplitudes in the others. We interpret this as due to different height of the X-ray emitting region among these objects. A height of ~0.2 white dwarf radii provides a plausible explanation for the low reflection amplitude of V709 Cas. Since emission regions above both poles are visible at certain spin phases, this can also explain the strong hard X-ray spin modulation. A shock height of ~0.05 white dwarf radii can explain our results on V1223 Sgr, while the shock height in NY Lup appears negligible.

Item Type:Article
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URLURL TypeDescription Paper
Rana, V.0000-0003-1703-8796
Additional Information:© 2015 American Astronomical Society. Received 20 May 2015, accepted for publication 23 June 2015, Published 10 July 2015. This research has made use of data obtained with the NuSTAR mission, a project led by the California Institute of Technology (Caltech), managed by the Jet Propulsion Laboratory (JPL) and funded by NASA. We acknowledge financial support from NASA under XMM-Newton grant NNX15AK63G and from ASI/INAF contract I/037/12/0.
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/037/12/0
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:novae, cataclysmic variables – X-rays: binaries
Issue or Number:2
Record Number:CaltechAUTHORS:20150810-154140351
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Official Citation:K. Mukai et al. 2015 ApJ 807 L30 doi:10.1088/2041-8205/807/2/L30
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59370
Deposited By: George Porter
Deposited On:11 Aug 2015 15:05
Last Modified:10 Nov 2021 22:19

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