A5044446925- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- ECG Monitoring and Analysis
University of Southampton
2023-2025
Center for Astrophysics Harvard & Smithsonian
2023
Abstract An α Ω dynamo, combining shear and cyclonic convection in the tachocline, is believed to generate solar cycle. However, this model cannot explain cycles fast rotators (with minimal shear) or fully convective stars (no tachocline); an analysis of these could therefore provide key insights into how work. We reexamine ASAS data for 15 M dwarfs, 11 which are presumed convective; addition newer ASAS-SN confirms roughly 12 them, while presenting new revised rotation periods 5 stars. The...
WZ Sge stars are highly evolved accreting white dwarf systems (AWDs) exhibiting remarkably large amplitude outbursts (a.k.a. super-outbursts), typically followed by short rebrightenings/echo outbursts. These have some of the lowest mass transfer rates among AWDs, making even low magnetic fields dynamically important. Such often invoked to explain phenomenology observed in these systems, such as their X-ray luminosity and long periods quiescence (30+ years). However, detection is very elusive...
Abstract Magnetic accreting white dwarfs in cataclysmic variables have been known to show bursts driven by different physical mechanisms; however, the burst occurrence is much rarer than their non-magnetic counterparts. DW Cnc a well-studied intermediate polar that showed with 4-magnitude amplitude 2007. Here we report on recent observed ASAS-SN reached peak luminosity of 6.6 × 1033 erg s−1, another 4 mag increase from its quiescent high state level. The released energy suggests these are...
Abstract WZ Sge stars are highly evolved accreting white dwarf systems (AWDs) exhibiting remarkably large amplitude outbursts (a.k.a. super-outbursts), typically followed by short rebrightenings/echo outbursts. These have some of the lowest mass transfer rates among AWDs, making even low magnetic fields dynamically important. Such often invoked to explain phenomenology observed in these systems, such as their X-ray luminosity and long periods quiescence (30+ years). However, detection is...
Abstract Proxima Cen (GJ 551; dM5.5e) is one of only about a dozen fully convective stars known to have stellar cycle, and the long-term X-ray monitoring. A previous analysis found that mid-UV observations, particularly two epochs data from Swift, were consistent with well-sampled ∼7 yr optical cycle seen in All Sky Automated Survey project (ASAS) data, but not convincing by themselves. The present work incorporates several years new ASAS-SN an additional 5 Swift XRT UVOT observations now...
Knitted electrodes provide numerous advantages over the gel typically used in clinical practice when designing wearable Electrocardiogram (ECG) systems. They have enhanced durability, better textile integration and do not dry out. However, higher skin/electrode impedance makes them susceptible to noise from electrical interference. Adding a buffer amplifier circuit close electrode, creating an 'active' is one way mitigate this. choice of where integrate these amplifiers garment remains....
ABSTRACT PBC J0801.2–4625 is an intermediate polar with a primary spin frequency of 66.08 d−1 and unknown orbital period. The long-term All Sky Automated Survey for Supernovae (ASAS-SN) light curve this system reveals four bursts, all which have similar peak amplitudes (∼2 mag) durations d). In work, we primarily study the timing properties system’s 2019 February burst, was simultaneously observed by both ASAS-SN Transiting Exoplanet Satellite (TESS). Pre-burst, 4.064 ± 0.002 d−1(5.906 0.003...
Almost all accreting black hole and neutron star X-ray binary systems (XRBs) exhibit prominent brightness variations on a few characteristic time-scales their harmonics. These quasi-periodic oscillations (QPOs) are thought to be associated with the precession of warped accretion disc, but physical mechanism that generates precessing warp remains uncertain. Relativistic frame dragging (Lense-Thirring precession) is one promising candidate, misaligned magnetic field an alternative, especially...
Proxima Cen (GJ 551; dM5.5e) is one of only about a dozen fully convective stars known to have stellar cycle, and the long-term X-ray monitoring. A previous analysis found that mid-UV observations, particularly two epochs data from Swift, were consistent with well sampled 7 yr optical cycle seen in ASAS data, but not convincing by themselves. The present work incorporates several years new ASAS-SN an additional five Swift XRT UVOT observations now spanning 2009 2021 coverage late 2000....
An $αΩ$ dynamo, combining shear and cyclonic convection in the tachocline, is believed to generate solar cycle. However, this model cannot explain cycles fast rotators (with minimal shear) or fully convective stars (no tachocline); analysis of such could therefore provide key insights into how these work. We reexamine ASAS data for 15 M dwarfs, 11 which are presumed convective; addition newer ASAS-SN confirms roughly a dozen them, while presenting new revised rotation periods five. The...