The connection between the UV/optical and X-ray emission in the neutron star low-mass X-ray binary Aql X-1
arXiv:2001.09903 · doi:10.1093/mnras/staa275
Abstract
Accreting neutron stars and black holes in low-mass X-ray binaries (LMXBs) radiate across the electromagnetic spectrum. Linking the emission produced at different wavelengths can provide valuable information about the accretion process and any associated outflows. In this work, we study simultaneous X-ray and UV/optical observations of the neutron star LMXB \source, obtained with the Neil Gehrels Swift Observatory during its 2013, 2014 and 2016 accretion outbursts. We find that the UV/optical and X-ray emission are strongly correlated during all three outbursts. For the 2013 and 2014 episodes, which had the best Swift sampling, we find that the correlation between the UV/optical and X-ray fluxes is significantly steeper during the decay (soft state) of the outburst than during the rise (hard-to-soft state). We observe an UV/optical hysteresis behaviour that is likely linked to the commonly known X-ray spectral hysteresis pattern. For the decays of the three outbursts we obtain a correlation index that cannot be directly explained by any single model. We suspect that this is a result of multiple emission processes contributing to the UV/optical emission, but we discuss alternative explanations. Based on these correlations, we discuss which mechanisms are likely dominating the UV/optical emission of Aql X-1.
arXiv comment11 pages, 6 figures. Accepted in MNRAS
References in corpus (67)
- Astropy: A Community Python Package for Astronomy
- Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
- Correcting for the Effects of Interstellar Extinction
- Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
- HI4PI: A full-sky HI survey based on EBHIS and GASS
- Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991
- The disc instability model of dwarf-novae and low-mass X-ray binary transients
- The Swift/BAT Hard X-ray Transient Monitor
- Ubiquitous equatorial accretion disc winds in black hole soft states
- Jets in neutron star X-ray binaries: a comparison with black holes
- A Global Spectral Study of Black Hole X-ray Binaries
- Global optical/infrared - X-ray correlations in X-ray binaries: quantifying disc and jet contributions
- Multi-wavelength observations of the 2002 outburst of GX 339-4: two patterns of X-ray-optical/near-infrared behavior
- Simultaneous Chandra and RXTE Spectroscopy of the Microquasar H~1743-322: Clues to Disk Wind and Jet Formation from a Variable Ionized Outflow
- Discovery of coherent millisecond X-ray pulsations in Aql X-1
- Black hole-like hysteresis and accretion states in neutron star low mass X-ray binaries
- Regulation of black-hole accretion by a disk wind during a violent outburst of V404 Cygni
- Swift Observations of the Cooling Accretion Disk of XTE J1817-330
- Hot accretion flow in black hole binaries: a link connecting X-rays to the infrared
- The Evolving Accretion Disc in the Black Hole X-ray Transient XTE J1859+226
- The Spin Distribution of Fast Spinning Neutron Stars in Low Mass X-Ray Binaries: Evidence for Two Sub-Populations
- Multiwavelength Spectrum of the Black Hole XTE J1118+480 in Quiescence
- On the Magnetic Prandtl Number Behavior of Accretion Disks
- Strong disc winds traced throughout outbursts in black-hole X-ray binaries
- Hard state neutron star and black hole X-ray binaries in the radio:X-ray luminosity plane
- Spectral State Transitions in Aql X-1: Evidence for `Propeller' Effects
- On the bolometric quiescent luminosity and luminosity swing of black hole candidate and neutron star low mass X-ray transients
- A mechanism for hysteresis in black hole binary state transitions
- A synchrotron self-Compton -- disk reprocessing model for optical/X-ray correlation in black hole X-ray binaries
- Spectral Fits to the 1999 Aql X-1 Outburst Data
- Multiwavelength spectral evolution during the 2011 outburst of the very faint X-ray transient Swift J1357.2-0933
- Stochastic Electron Acceleration During the NIR and X-ray Flares in Sagittarius A*
- The disc-jet coupling in the neutron star X-ray binary Aquila X-1
- Spitzer Reveals Infrared Optically-Thin Synchrotron Emission from the Compact Jet of the Neutron Star X-Ray Binary 4U 0614+091
- The role of the disk magnetization on the hysteresis behavior of X-ray binaries
- A Global Study of the Behaviour of Black Hole X-ray Binary Discs
- Outburst Morphology in the Soft X-ray Transient Aquila X-1
- Multicolour observations of V404 Cyg with ULTRACAM
- The donor of Aquila X-1 revealed by high angular resolution near-infrared spectroscopy
- Thermal Disk Winds in X-ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive Outflows
- A physical model for state transitions in black hole X-ray binaries
- Daily, multiwavelength Swift monitoring of the neutron star low-mass X-ray binary Cen X-4: evidence for accretion and reprocessing during quiescence
- Neutron star crust cooling in KS 1731-260: the influence of accretion outburst variability on the crustal temperature evolution
- Measuring A Truncated Disk in Aquila X-1
- Radio pulse search and X-Ray monitoring of SAX J1808.4-3658: What Causes its Orbital Evolution?
- Constraining the properties of neutron star crusts with the transient low-mass X-ray binary Aql X-1
- A cooling neutron star crust after recurrent outbursts: Modelling the accretion outburst history of Aql X-1
- The evolving jet spectrum of the neutron star X-ray binary Aql X-1 in transitional states during its 2016 outburst
- Accretion Geometry of the Low-Mass X-ray Binary Aquila X-1 in the Soft and Hard States
- UV emission from young and middle-aged pulsars: Connecting X-rays with the optical
- Truncation of the Accretion Disk at One Third of the Eddington Limit in the Neutron Star Low-Mass X-ray Binary Aquila X-1
- Multiwavelength Observations of Swift J1753.5-0127
- Intermittent dipping in a low-mass X-ray Binary
- Classification and Spectral Evolution of Outbursts of Aql X-1
- An X-ray-UV correlation in Cen X-4 during quiescence
- Quasi-simultaneous radio and X-ray observations of Aql X-1: probing low luminosities
- Multi-Wavelength Coverage of State Transitions in the New Black Hole X-Ray Binary Swift J1910.2-0546
- Sub-mm Jet Properties of the X-Ray Binary Swift J174526
- The Ultraviolet Spectral Energy Distributions of Quiescent Black Holes and Neutron Stars
- Hot Outflowing Gas from the X-ray Binary Hercules X-1
- Hystereses in dwarf nova outbursts and low-mass X-ray binaries
- Hubble Space Telescope Observations of the Black Hole X-ray Transient GRO J0422+32 Near Quiescence
- On the morphology of outbursts of accreting millisecond X-ray pulsar Aquila X-1
- A UV flux drop preceding the X-ray hard-to-soft state transition during the 2010 outburst of GX 339-4
- Evolution of broad-band SED during outburst rise in NS X-ray Nova Aql X-1
- Swift monitoring of Cygnus X-2: investigating the NUV-X-ray connection
- FUSE Observations of a Full Orbit of Scorpius X-1
Cited by in corpus (7)
- Nebular emission from young stellar populations including binary stars
- Time-lag between disk and corona radiation leads to hysteresis effect observed in black-hole X-ray binary MAXI J1348-630
- The Luminosity Phase Space of Galactic and Extragalactic X-ray Transients Out to Intermediate Redshifts
- Optical nebular emission following the most luminous outburst of Aquila X-1
- Return of 4U~1730--22 after 49 years silence: the spectral properties of the 2021/2022 outbursts observed by NICER and Insight-HXMT and the soft-to-hard state transition caused by the propeller effect
- The origin of UV/optical emission in the black hole low-mass X-ray binary Swift J1753.5-0127
- Optical and X-ray variations during 5 outbursts of Aql X-1 in 3.6 years from 2016