XMM-Newton and Chandra Observations of the Candidate Fermi-LAT Pulsar 4FGL J1015.5-6030

• Published in: The Astrophysical journal Vol. 951; no. 1; pp. 80 - 88
• Main Authors: Hare, Jeremy, Kargaltsev, Oleg, Younes, George, Pavlov, George G., Volkov, Igor
• Format: Journal Article
• Language: English
• Published: Goddard Space Flight Center The American Astronomical Society 01-07-2023; American Astronomical Society; IOP Publishing
• Subjects: Astronomy; Astrophysics; Blackbody; Emission; Emissions; Gamma-ray sources; Luminosity; Magnetospheres; Nebulae; Neutron stars; Point sources; Power law; Pulsar wind nebulae; Pulsar winds; Pulsars; Stellar winds; X ray sources; X ray spectra; X-ray astronomy; X-rays; XMM (spacecraft); Gamma-Ray Sources; X-Ray Sources; Pulsar Wind Nebulae; Pulsars
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/acd24e

4FGL J1015.5-6030 is an unidentified Fermi-LAT source hosting a bright, extended X-ray source whose X-ray spectrum is consistent with that of a young pulsar, yet no pulsations have been found. Here we report on XMM-Newton timing and Chandra imaging observations of the X-ray counterpart of 4FGL J1015.5-6030. We find no significant periodicity from the source and place a 3σ upper limit on its pulsed fraction of 34%. The Chandra observations resolve the point source from the extended emission. We find that the point source's spectrum is well fit by a blackbody model, with temperature kT = 0.205 ± 0.009 keV, plus a weak power-law component, which is consistent with a thermally emitting neutron star with a magnetospheric component. The extended emission spans angular scales of a few arcseconds up to about 30'' from the point source and its spectrum is well fit by a power-law model with a photon index Γ = 1.70 ± 0.05. The extended emission's spectrum and 0.5–10 keV luminosity of 4 × 1032 erg s−1 (at a plausible distance of 2 kpc) are consistent with that of a pulsar wind nebula. Based on a comparison to other GeV and X-ray pulsars, we find that this putative pulsar is likely a middle-aged (i.e., τ ∼ 0.1–1 Myr) radio-quiet pulsar with Ė~1034-1035erg s−1.