NICER Observation of the Temporal and Spectral Evolution of Swift J1818.0-1607: a Missing Link between Magnetars and Rotation Powered Pulsars

Abstract

We report on the hard X-ray burst and the first ~100 days NICER monitoring of the soft X-ray temporal and spectral evolution of the newly-discovered magnetar Swift J1818.0-1607. The burst properties are typical of magnetars with a duration of $T_{90}=10\pm 4$ ms and a temperature of $kT=8.4\pm 0.7$ keV. The 2--8 keV pulse shows a broad, single peak profile with a pulse fraction increasing with time from 30% to 43%. The NICER observations reveal strong timing noise with $\dot{\nu }$ varying erratically by a factor of 10, with an average long-term spin-down rate of $\dot{\nu }=(-2.48\pm 0.03)\times 10^{-11}$~s${}^{-2}$, implying an equatorial surface magnetic field of $2.5\times 10^{14}$ G and a young characteristic age of $\sim$470 yr. We detect a large spin-up glitch at MJD 58928.56 followed by a candidate spin-down glitch at MJD 58934.81, with no accompanying flux enhancements. The persistent soft X-ray spectrum of Swift~J1818.0-1607 can be modeled as an absorbed blackbody with a temperature of ~1 keV. Its flux decayed by ~60% while the modeled emitting area decreased by ~30% over the NICER observing campaign. This decrease, coupled with the increase in the pulse fraction points to a shrinking hot spot on the neutron star surface. Assuming a distance of 6.5 kpc, we measure a peak X-ray luminosity of $1.9\times 10^{35}$ erg/s, lower than its spin-down luminosity of $7.2\times 10^{35}$ erg/s. Its quiescent thermal luminosity is $\lesssim 1.7\times 10^{34}$ erg/s, lower than those of canonical young magnetars. We conclude that Swift J1818.0-1607 is an important link between regular magnetars and high magnetic field rotation powered pulsars.

arXiv comment13 pages, 4 figures, 2tables, accepted for publication in ApJ

References in corpus (54)

• On the Absorption of X-rays in the Interstellar Medium
• The Burst Alert Telescope (BAT) on the Swift MIDEX Mission
• Magnetars
• Calibration of X-ray absorption in our Galaxy
• A study of 315 glitches in the rotation of 102 pulsars
• Unifying the observational diversity of isolated neutron stars via magneto-thermal evolution models
• Cooling neutron star in the Cassiopeia~A supernova remnant: Evidence for superfluidity in the core
• A low-magnetic-field Soft Gamma Repeater
• 1E 1547.0-5408: a radio-emitting magnetar with a rotation period of 2 seconds
• Magneto--thermal evolution of neutron stars
• Magnetar-like Emission from the Young Pulsar in Kes 75
• A Radio-loud Magnetar in X-ray Quiescence
• Magnetar Spin-Down
• A unified model of the magnetar and radio pulsar bursting phenomenology
• Systematic study of magnetar outbursts
• 16 Years of RXTE Monitoring of Five Anomalous X-ray Pulsars
• Discovery of a New Soft Gamma Repeater, SGR 1627-41
• An Anti-Glitch in a Magnetar
• The Correlation between Dispersion Measure and X-ray Column Density from Radio Pulsars
• Physical Mechanisms for the Variable Spin-down of SGR 1900+14
• The Prelude to and Aftermath of the Giant Flare of 2004 December 27: Persistent and Pulsed X-ray Properties of SGR 1806-20 from 1993 to 2005
• The outburst decay of the low magnetic field magnetar SGR 0418+5729
• Radio properties of the magnetar near Sagittarius A* from observations with the Australia Telescope Compact Array
• A Magnetar-like Outburst from a High-B Radio Pulsar
• Magnetar-like activity from the central compact object in the SNR RCW103
• X-ray and radio observations of the magnetar SGR J1935+2154 during its 2014, 2015, and 2016 outbursts
• RXTE Monitoring of the Anomalous X-ray Pulsar 1E 1048.1-5937: Long-Term Variability and the 2007 March Event
• Chandra X-ray Detection of the High-Magnetic-Field Radio Pulsar PSR J1718-3718
• Timing and Flux Evolution of the Galactic Center Magnetar SGR J1745-2900
• Electron-positron flows around magnetars
• The Five Year Fermi/GBM Magnetar Burst Catalog
• Magnetar Broadband X-ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE
• 30 Glitches in slow pulsars
• Radio disappearance of the magnetar XTE J1810-197 and continued X-ray timing
• A very young radio-loud magnetar
• Magnetar-like X-ray Bursts from a Rotation Powered Pulsar, PSR J1119-6127
• X-ray and Radio Timing of the Pulsar in 3C 58
• The wind nebula around magnetar Swift J1834.9-0846
• The X-ray outburst of the Galactic Centre magnetar SGR J1745-2900 during the first 1.5 year
• Deep NuSTAR and Swift Monitoring Observations of the Magnetar 1E 1841-045
• Suzaku Discovery of a Hard X-Ray Tail in the Persistent Spectra from the Magnetar 1E 1547.0-5408 during its 2009 Activity
• Deep X-ray Observations of the Young High-Magnetic-Field Radio Pulsar J1119-6127 and Supernova Remnant G292.2-0.5
• The Sleeping Monster: NuSTAR observations of SGR 1806-20, 11 years after the Giant Flare
• High Magnetic Field Rotation-powered Pulsars
• Post-Outburst Radio Observations of the High Magnetic Field Pulsar PSR J1119-6127
• Oxygen Abundances in the Milky Way Using X-ray Absorption Measurements Towards Galaxy Clusters
• General Relativistic Constraints on Emission Models of Anomalous X-ray Pulsars
• A radiatively-quiet glitch and anti-glitch in the magnetar 1E 2259+586
• Two new outbursts and transient hard X-rays from 1E 1048.1$-$5937
• Swift observations of two outbursts from the magnetar 4U 0142+61
• Chandra Phase-Resolved Spectroscopy of the High Magnetic Field Pulsar B1509-58
• A systematic study of soft X-ray pulse profiles of magnetars in quiescence
• More than meets the eye: magnetars in disguise
• X-Ray Observations of Magnetar SGR 0501+4516 from Outburst to Quiescence

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• High Frequency Radio Observations of Two Magnetars, PSR J1622$-$4950 and 1E 1547.0$-$5408
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