A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger

Abstract

Neutron star-neutron star mergers are known to be associated with short gamma-ray bursts. If the neutron star equation of state is sufficiently stiff, at least some of such mergers will leave behind a supramassive or even a stable neutron star that spins rapidly with a strong magnetic field (i.e., a magnetar). Such a magnetar signature may have been observed as the X-ray plateau following a good fraction (up to 50%) of short gamma-ray bursts, and it has been expected that one may observe short gamma-ray burst-less X-ray transients powered by double neutron star mergers. A fast X-ray transient (CDF-S XT1) was recently found to be associated with a faint host galaxy whose redshift is unknown. Its X-ray and host-galaxy properties allow several possibleexplanations including a short gamma-ray burst seen off axis, a low-luminosity gamma-ray burst at high redshift, or a tidal disruption event involving an intermediate mass black hole and a white dwarf. Here we report a second X-ray transient, CDF-S XT2, that is associated with a galaxy at redshift z = 0.738. The light curve is fully consistent with being powered by a millisecond magnetar. More intriguingly, CDF-S XT2 lies in the outskirts of its star-forming host galaxy with a moderate offset from the galaxy center, as short bursts often do. The estimated event rate density of similar X-ray transients, when corrected to the local value, is consistent with the double neutron star merger rate density inferred from the detection of GW170817.

29 pages, 4 figures, 3 tables, published in Nature on 11 April 2019

References in corpus (14)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• Constraining the Maximum Mass of Neutron Stars From Multi-Messenger Observations of GW170817
• The Chandra Deep Field-South Survey: 7 Ms Source Catalogs
• Short Duration Gamma-Ray Bursts with Extended Emission from Proto-Magnetar Spin-Down
• X-Ray Flares from Postmerger Millisecond Pulsars
• Stellar masses from the CANDELS survey: the GOODS-South and UDS fields
• The Millisecond Magnetar Central Engine in short GRBs
• The nature of the dwarf starforming galaxy associated with GRB 060218 / SN2006aj
• A Comparative Study of Long and Short GRBs. I. Overlapping Properties
• The Chandra Deep Fields: Lifting the Veil on Distant Active Galactic Nuclei and X-Ray Emitting Galaxies
• Deepest view of AGN X-ray variability with the 7 Ms Chandra Deep Field-South survey

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