A detailed X-ray investigation of PSR J2021+4026 and $\gamma$-Cygni supernova remnant

Abstract

We have investigated the field around the radio-quiet $\gamma$-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and a ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature which suggests the pulsation is originated from a hot polar cap with $T\sim 3\times 10^6$ K on the surface of a rotating neutron star. On the other hand, the power-law component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chandra data, we have confirmed the presence of bow-shock nebula which extends from the pulsar to west by ~10 arcsec. The orientation of this nebular feature suggests that the pulsar is probably moving eastward which is consistent with the speculated proper motion by extrapolating from the nominal geometrical center of the supernova remnant (SNR) G78.2+2.1 to the current pulsar position. For G78.2+2.1, our deep XMM-Newton observation also enables a study of the central region and part of the southeastern region with superior photon statistics. The column absorption derived for the SNR is comparable with that for PSR J2021+4026, which supports their association. The remnant emission in both examined regions are in an non-equilibrium ionization state. Also, the elapsed time of both regions after shock-heating is apparently shorter than the Sedov age of G78.2+2.1. This might suggest the reverse shock has reached the center not long ago. Apart from PSR J2021+4026 and G78.2+2.1, we have also serendipitously detected an X-ray flash-like event XMM J202154.7+402855 from this XMM-Newton observation.

arXiv comment45 pages, 10 figures, 2 tables, accepted for publication in ApJ

References in corpus (30)

• The USNO-B Catalog
• A statistical study of 233 pulsar proper motions
• The Second Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Fermi Large Area Telescope Bright Gamma-ray Source List
• Supernova remnants: the X-ray perspective
• The First Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• The Third US Naval Observatory CCD Astrograph Catalog (UCAC3)
• Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• The Mouse That Soared: High Resolution X-ray Imaging of the Pulsar-Powered Bow Shock G359.23-0.82
• Chandra/ACIS Subpixel Event Repositioning. II. Further Refinements and Comparison between Backside and Front-side Illuminated X-ray CCDs
• A 200-s Quasi-Periodicity Following the Tidal Disruption of a Star by a Dormant Black Hole
• PSR J2021+4026 in the Gamma Cygni region: the first variable gamma-ray pulsar seen by the Fermi LAT
• Long-term Properties of Accretion Disks in X-ray Binaries: I. the variable third period in SMC X-1
• ASCA View of the Supernova Remnant Gamma Cygni (G78.2+2.1): Bremsstrahlung X-ray Spectrum from Loss-flattened Electron Distribution
• Long-term Properties of Accretion Disks in X-ray Binaries: II. Stability of Radiation-Driven Warping
• X-ray emission properties of the old pulsar PSR B2224+65
• Pulsar Wind Nebulae and the X-Ray Emission of Non-Accreting Neutron Stars
• Discovery of TeV Gamma-ray Emission Toward Supernova Remnant SNR G78.2+2.1
• X-ray and Radio Observations of the gamma Cygni Supernova Remnant G78.2+2.1
• XMM-Newton observation of PSR B2224+65 and its jet
• Discovery of X-ray Pulsation from the Geminga-like Pulsar PSR J2021+4026
• A multi-wavelength search for a counterpart of the unidentified gamma-ray source 3EG J2020+4017 (2CG078+2)
• Multiwavelength properties of a new Geminga-like pulsar: PSR J2021+4026
• Bow shocks around pulsars and neutron stars
• Challenges in the modelling of tidal disruption events lightcurves
• The Identification of the X-ray Counterpart to PSR J2021+4026
• Resolving the bow-shock nebula around the old pulsar PSR B1929+10 with multi-epoch Chandra observations
• Identification campaign of supernova remnant candidates in the Milky Way. II. X-ray studies of G38.7-1.4
• The Effects of Rotation on Thermal X-Ray Afterglows Resulting from Pulsar Glitches

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• Study of the GeV to TeV morphology of the $\gamma$-Cygni SNR (G78.2+2.1) with MAGIC and Fermi-LAT
• The Age Evolution of the Radio Morphology of Supernova Remnants
• X-ray study of Variable Gamma-ray Pulsar PSR J2021+4026
• A search for radio pulsars in five nearby supernova remnants
• Strongly pulsed thermal X-rays from a single extended hot spot on PSR J2021+4026
• AGILE study of the gamma-ray emission from the SNR G78.2+2.1 (Gamma Cygni)
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