Monitoring Observations of SMC X-1's Excursions (MOOSE) I: Program Description and Initial High-State Spectral Results
arXiv:2206.06558 · doi:10.1093/mnras/stac1674
Abstract
SMC X-1 has exhibited three super-orbital period excursions since the onset of X-ray monitoring beginning with RXTE's launch in 1995. NICER has recently probed a fourth observed excursion beginning in 2021 with our program Monitoring Observations of SMC X-1's Excursions (MOOSE). These sensitive new MOOSE data probe different super-orbital periods and phases within them. Spectral fits to the high-state continuum during April 2021 to January 2022 show that the intrinsic spectral shapes are characterised by a soft (kT~0.19 keV) disc component and a hard (Gamma~0.7) power-law tail. When the 2021-2022 NICER observations, taken during an excursion, are compared to 2016 XMM-Newton observations (outside of an excursion), we find little evidence for intrinsic spectral variability across the high-states, but find evidence for a >3 sigma change in the absorption, although we caution that there may be calibration differences between the two instruments. Thus, over different lengths of super-orbital periods, we see little evidence for intrinsic spectral changes in the high-state. Upcoming studies of the pulse profiles may shed light on the mechanism behind the excursions.
arXiv commentaccepted to MNRAS
References in corpus (45)
- The NumPy array: a structure for efficient numerical computation
- On the Absorption of X-rays in the Interstellar Medium
- Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
- An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
- The Swift/BAT Hard X-ray Transient Monitor
- Optimal binning of X-ray spectra and response matrix design
- False periodicities in quasar time-domain surveys
- Precessing warped accretion discs in X-ray binaries
- A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source
- XMM-Newton and Chandra Cross Calibration Using HIFLUGCS Galaxy Clusters: Systematic Temperature Differences and Cosmological Impact
- Discovery of a 2.8 s pulsar in a 2 d orbit High-Mass X-ray Binary powering the Ultraluminous X-ray source ULX-7 in M51
- Determination of the mass of the neutron star in SMC X-1, LMC X-4 and Cen X-3 with VLT/UVES
- Quasi-Periodic Occultation by a Precessing Accretion Disk and Other Variabilities of SMC X-1
- Long-term Properties of Accretion Disks in X-ray Binaries: I. the variable third period in SMC X-1
- Characterizing X-ray binary long-term variability
- Spectral Changes in the Hyperluminous Pulsar in NGC 5907 as a Function of Super-Orbital Phase
- Super-Eddington Accretion onto the Neutron Star NGC 7793 P13: Broadband X-ray Spectroscopy and Ultraluminous X-ray Sources
- A 78 Day X-ray Period Detected from NGC 5907 ULX1 by Swift
- Nature of the Soft Spectral Component in the X-ray Pulsars SMC X-1 and LMC X-4
- Long-term Properties of Accretion Disks in X-ray Binaries: II. Stability of Radiation-Driven Warping
- Superorbital Periodic Modulation in Wind-Accretion High-Mass X-ray Binaries from Swift BAT Observations
- A ~60-day super-orbital period originating from the ultraluminous X-ray pulsar in M82
- All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2
- Three dimensional SPH simulations of radiation-driven warped accretion discs
- Pulse-phase spectroscopy of SMC X-1 with Chandra and XMM-Newton: reprocessing by a precessing disk?
- Tracking the Orbital and Super-orbital Periods of SMC X-1
- Swift monitoring of M51: A 38-day super-orbital period for the pulsar ULX7 and a new transient ULX
- SPH simulations of irradiation-driven warped accretion discs and the long periods in X-ray binaries
- Robust period estimation using mutual information for multi-band light curves in the synoptic survey era
- BeppoSAX observations of the accretion-powered X-ray pulsar SMC X-1
- Orbital and super-orbital periods in ULX pulsars, disc-fed HMXBs, Be/X-ray binaries and double-periodic variables
- Phase Variation in the Pulse Profile of SMC X-1
- Modeling the precession of the warped inner accretion disk in the pulsars LMC X-4 and SMC X-1 with NuSTAR and XMM-Newton
- Analysis of RXTE-PCA Observations of SMC X-1
- Time-Frequency Analysis of Superorbital Modulation of X-ray Binary SMC X-1 by Hilbert-Huang Transform
- Observing the transient pulsations of SMC X-1 with NuSTAR
- Is superorbital modulation in SMC X-1 caused by absorption in warped precessing accretion disc?
- Longterm properties of accretion discs in X-ray Binaries - III. A search for spin-superorbital correlation in SMC X-1
- Monitoring the Superorbital Period Variation and the Spin Period Evolution of SMC X-1
- An X-Ray Spectroscopic Study of the SMC X-1/Sk 160 System
- Superorbital Phase-Resolved Analysis of SMC X-1
- Photoionized Lines in the X-ray Spectra of SMC X-1
- Evolution of the spin, spectrum and super-orbital period of the ultraluminous X-ray pulsar M51 ULX7
- Investigation of the timing and spectral properties of an Ultra-luminous X-ray pulsar NGC 7793 P13
- Large optical modulations during 2018 outburst of MAXI J1820+070 reveal evolution of warped accretion disc through X-ray state change