On the properties of a newborn magnetar powering the X-ray transient CDF-S XT2

Abstract

Very recently \citet{XueYQ2019} reported an important detection of the X-ray transient, CDF-S XT2, whose light curve is analogous to X-ray plateau features of gamma-ray burst afterglows. They suggested that this transient is powered by a remnant stable magnetar from a binary neutron star merger since several pieces of evidence (host galaxy, location, and event rate) all point toward such an assumption. In this paper, we revisit this scenario and confirm that this X-ray emission can be well explained by the internal gradual magnetic dissipation process in an ultra-relativistic wind of the newborn magnetar. We show that both the light curve and spectral evolution of CDF-S XT2 can be well fitted by such a model. Furthermore, we can probe some key properties of the central magnetar, such as its initial spin period, surface magnetic field strength and wind saturation Lorentz factor.

5 pages, 3 figures, ApJL accepted

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Cited by in corpus (13)

• A long-duration gamma-ray burst with a peculiar origin
• The evolution of binary neutron star post-merger remnants: a review
• Science objectives of the Einstein Probe mission
• Extragalactic fast X-ray transient candidates discovered by Chandra (2000-2014)
• Gravitational waves or deconfined quarks: what causes the premature collapse of neutron stars born in short gamma-ray bursts?
• Kilonova Emission From Black Hole-Neutron Star Mergers. II. Luminosity Function and Implications for Target-of-opportunity Observations of Gravitational-wave Triggers and Blind Searches
• On the diversity of magnetar-driven kilonovae
• Discovery of Three Candidate Magnetar-powered Fast X-ray Transients from Chandra Archival Data
• Constraining the long-lived magnetar remnants in short gamma-ray bursts from late-time radio observations
• CDF-S XT1 and XT2: White Dwarf Tidal Disruption Events by Intermediate-Mass Black Holes?
• Energy injection driven by precessing jets in gamma-ray burst afterglows
• New JWST redshifts for the host galaxies of CDF-S XT1 and XT2: understanding their nature
• Evidence of X-ray plateaus driven by the magnetar spindown winds in gamma-ray burst afterglows