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Title: X-Ray Observation of the Roche-lobe-filling White Dwarf plus Hot Subdwarf System ZTF J213056.71+442046.5
Abstract ZTF J213056.71+442046.5 is the prototype of a small class of recently discovered compact binaries composed of a white dwarf and a hot subdwarf that fills its Roche lobe. Its orbital period of only 39 minutes is the shortest known for the objects in this class. Evidence for a high orbital inclination ( i = 86°) and for the presence of an accretion disk has been inferred from a detailed modeling of its optical photometric and spectroscopic data. We report the results of an XMM-Newton observation carried out on 2021 January 7. ZTF J213056.71+442046.5 was clearly detected by the Optical Monitor, which showed a periodic variability in the UV band (200–400 nm), with a light curve similar to that seen at longer wavelengths. Despite accretion on the white dwarf at an estimated rate of the order of 10 −9 M ⊙ yr −1 , no X-rays were detected with the EPIC instrument, with a limit of ∼10 30 erg s −1 on the 0.2–12 keV luminosity. We discuss possible explanations for the lack of a strong X-ray emission from this system.  more » « less
Award ID(s):
2107982
NSF-PAR ID:
10373961
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
931
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
13
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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