Query : 2022A&A...666A.150M

2022A&A...666A.150M - Astronomy and Astrophysics, volume 666A, 150 (2022/10-1)

An intermediate polar candidate toward the Galactic plane.


Abstract (from CDS):

Context. For the past decade, it has been suggested that intermediate polars (IPs), a subclass of magnetic cataclysmic variables (CVs), are one of the main contributors to the hard diffuse X-ray emission from the Galactic center (GC) and Galactic ridge.
Aims. In our ongoing XMM-Newton survey of the central region of the Galactic disk (20° ×2°), we detected a persistent IP candidate, 1.7° away from the GC. In this work, we better characterize the behavior of this source by looking at the new and archival XMM-Newton data.
Methods. We performed a detailed X-ray spectral modeling of the source. Furthermore, we searched for X-ray pulsations in the light curve as well as its counterpart at other wavelengths.
Results. The XMM-Newton spectrum (0.8-10 keV) of the source is described by a partial covering collisionally ionized diffuse gas with plasma temperature $ kT=15.7^{+20.9}_{-3.6} $ keV. In addition, the spectrum shows the presence of iron lines at E = 6.44, 6.65, and 6.92 keV with equivalent widths of $ 194^{+89}_{-70} $, $ 115^{+79}_{-75} $, and $ 98^{+93}_{-74} $ eV, respectively. The X-ray light curve shows a coherent modulation with a period of P = 432.44 ± 0.36 s, which we infer is the spin period of the white dwarf. The white dwarf mass estimated from fitting a physical model to the spectrum results in $ M_{\mathrm{WD}}=1.05^{+0.16}_{-0.21}\,M_{\odot} $. We were able to find a likely optical counterpart in the Gaia catalog with a G magnitude of 19.26, and the distance to the source derived from the measured Gaia parallax is ∼4.3 kpc.
Conclusions. We provide an improved source localization with subarcsec accuracy. The spectral modeling of the source indicates the presence of intervening circumstellar gas, which absorbs the soft X-ray photons. The measured equivalent width of the iron lines and the detection of the spin period in the light curve are consistent with those from IPs.

Abstract Copyright: © S. Mondal et al. 2022

Journal keyword(s): X-rays: binaries - Galaxy: center - Galaxy: disk - white dwarfs - novae - cataclysmic variables

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 4XMM J174033.8-301501 X 17 40 33.8 -30 15 01           ~ 2 0
2 Suzaku J174035-301416 CV? 17 40 35.6 -30 14 16           ~ 3 0
3 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14463 0
4 NAME Galactic Bulge reg ~ ~           ~ 4309 0
5 NAME Galactic Ridge ? ~ ~           ~ 500 1

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