X-ray burst and persistent emission properties of the magnetar SGR 1830-0645 in outburst

Abstract

We report on NICER X-ray monitoring of the magnetar SGR 1830-0645 covering 223 days following its October 2020 outburst, as well as Chandra and radio observations. We present the most accurate spin ephemerides of the source so far: $\nu =0.096008680(2)$~Hz, $\dot{\nu }=-6.2(1)\times 10^{-14}$~Hz~s${}^{-1}$, and a significant second and third frequency derivative terms indicative of non-negligible timing noise. The phase-averaged 0.8--7~keV spectrum is well fit with a double-blackbody (BB) model throughout the campaign. The BB temperatures remain constant at 0.46 and 1.2 keV. The areas and flux of each component decreased by a factor of 6, initially through a steep decay trend lasting about 46 days followed by a shallow long-term one. The pulse shape in the same energy range is initially complex, exhibiting three distinct peaks, yet with clear continuous evolution throughout the outburst towards a simpler, single-pulse shape. The rms pulsed fraction is high and increases from about 40% to 50%. We find no dependence of pulse shape or fraction on energy. These results suggest that multiple hotspots, possibly possessing temperature gradients, emerged at outburst-onset, and shrank as the outburst decayed. We detect 84 faint bursts with \nicer, having a strong preference for occurring close to the surface emission pulse maximum the first time this phenomenon is detected in such a large burst sample. This likely implies a very low altitude for the burst emission region, and a triggering mechanism connected to the surface active zone. Finally, our radio observations at several epochs and multiple frequencies reveal no evidence of pulsed or burst-like radio emission.

arXiv commentApJ accepted

References in corpus (62)

• Magnetars
• A fast radio burst associated with a Galactic magnetar
• A bright millisecond-duration radio burst from a Galactic magnetar
• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• Electrodynamics of Magnetars: Implications for the Persistent X-ray Emission and Spindown of the Soft Gamma Repeaters and Anomalous X-ray Pulsars
• Studies in Astronomical Time Series Analysis. VI. Bayesian Block Representations
• Magnetars: the physics behind observations
• Transient pulsed radio emission from a magnetar
• Unifying the observational diversity of isolated neutron stars via magneto-thermal evolution models
• The Giant Flare of 1998 August 27 from SGR 1900+14: II. Radiative Mechanism and Physical Constraints on the Source
• INTEGRAL discovery of a burst with associated radio emission from the magnetar SGR 1935+2154
• Untwisting magnetospheres of neutron stars
• Explosive reconnection in magnetars
• Magnetar-like Emission from the Young Pulsar in Kes 75
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• A peculiar hard X-ray counterpart of a Galactic fast radio burst
• Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586 during its 2002 Outburst
• Statistical properties of SGR 1900+14 bursts
• PINT: A Modern Software Package for Pulsar Timing
• Systematic study of magnetar outbursts
• Magnetar heating
• Repeating Fast Radio Bursts from Magnetars with Low Magnetospheric Twist
• FETCH: A deep-learning based classifier for fast transient classification
• The outburst decay of the low magnetic field magnetar SGR 0418+5729
• Detection of two bright radio bursts from magnetar SGR 1935+2154
• A Magnetar-like Outburst from a High-B Radio Pulsar
• Magnetar-like activity from the central compact object in the SNR RCW103
• Tearing instability in relativistic magnetically dominated plasmas
• Magnetically-driven crustquakes in neutron stars
• X-ray Bursts from the Transient Magnetar Candidate XTE J1810-197
• The NICER View of the 2020 Burst Storm and Persistent Emission of SGR 1935+2154
• The Distance and Age of the SNR Kes 73 and AXP 1E 1841-045
• 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
• The 2009 outburst of magnetar 1E 1547-5408: Persistent radiative and burst properties
• Radio disappearance of the magnetar XTE J1810-197 and continued X-ray timing
• Thermoplastic waves in magnetars
• The Distances of SNR W41 and overlapping HII regions
• Simultaneous multifrequency radio observations of the Galactic Centre magnetar SGR J1745-2900
• A very young radio-loud magnetar
• Magnetic-field evolution in a plastically-failing neutron-star crust
• High Energy Polarimetry of Prompt GRB Emission
• Global Crustal Dynamics of Magnetars in Relation to their Bright X-ray Outbursts
• Magnetar-like X-ray Bursts from a Rotation Powered Pulsar, PSR J1119-6127
• The wind nebula around magnetar Swift J1834.9-0846
• The 2006-2007 Active Phase of Anomalous X-ray Pulsar 4U 0142+61: Radiative and Timing Changes, Bursts, and Burst Spectral Features
• Young magnetars with fracturing crusts as fast radio burst repeaters
• Particle-in-cell simulations of the twisted magnetospheres of magnetars
• Pulse Morphology of the Galactic Center Magnetar PSR J1745-2900
• Magnetar field evolution and crustal plasticity
• Magnetar activity mediated by plastic deformations of neutron star crust
• Post-Outburst Radio Observations of the High Magnetic Field Pulsar PSR J1119-6127
• A Dual-band Radio Observation of FRB 121102 with the Deep Space Network and the Detection of Multiple Bursts
• NICER Observation of the Temporal and Spectral Evolution of Swift J1818.0-1607: a Missing Link between Magnetars and Rotation Powered Pulsars
• Multiwavelength Radio Observations of Two Repeating Fast Radio Burst Sources: FRB 121102 and FRB 180916.J0158+65
• XMM-Newton observations of SGR 1806-20 over seven years following the 2004 Giant Flare
• Two new outbursts and transient hard X-rays from 1E 1048.1$-$5937
• Swift observations of two outbursts from the magnetar 4U 0142+61
• The impulsive phase of magnetar giant flares: assessing linear tearing as the trigger mechanism
• The new magnetar SGR J1830-0645 in outburst
• Polarized Radiation Transfer in Neutron Star Surface Layers
• Observations of Radio Magnetars with the Deep Space Network

Cited by in corpus (4)

• Quasi-periodic sub-pulse structure as a unifying feature for radio-emitting neutron stars
• Multiwavelength Constraints on the Origin of a Nearby Repeating Fast Radio Burst Source in a Globular Cluster
• The 2022 high-energy outburst and radio disappearing act of the magnetar 1E 1547.0-5408
• AstroSat observation of the magnetar SGR J1830$-$0645 during its first detected X-ray outburst