196,606 research outputs found
M Dwarf Flare Continuum Variations on One-Second Timescales: Calibrating and Modeling of ULTRACAM Flare Color Indices
No full text<p>These files contain the ULTRACAM light curves, the ULTRACAM flare color indices, the APO/DIS spectral data, and the NMSU 1-m U-band photometry from "M Dwarf Flare Continuum Variations on One-Second Timescales: Calibrating and Modeling of ULTRACAM Flare Color Indices", Kowalski, A. F., Mathioudakis, M., Hawley, S. L., Wisniewski, J. P., Dhillon, V. S., Marsh, T. R., Hilton, E. J., & Brown, B. P., 2016, Astrophysical Journal in press. See the included ReadMe file for detailed information on the files.</p>
The 2008 RAS national astronomy meeting
No full textThis year's RAS National Astronomy Meeting was held at Queen's University Belfast from 31 March to 4 April. Also joining NAM 2008 were the meetings of the UK Solar Physics (UKSP) and the Magnetospheric, Ionospheric and Solar-Terrestrial (MIST) special interest groups. The event was organized by QUB scientists within the Astrophysics Research Centre and the Centre for Theoretical Atomic, Molecular and Optical Physics. Alan Fitzsimmons, Mihalis Mathioudakis and Andrew Kavanagh report.</p
Plasma properties and Stokes profiles during the lifetime of a photospheric magnetic bright point
No full textAims: In this paper we aim to investigate the evolution of plasmaproperties and Stokes parameters in photospheric magnetic bright pointsusing 3D magneto-hydrodynamical simulations and radiative diagnostics ofsolar granulation. Methods: Simulated time-dependent radiationparameters and plasma properties were investigated throughout theevolution of a bright point. Synthetic Stokes profiles for the FeI630.25 nm line were calculated, which also allowed the evolution of theStokes-I line strength and Stokes-V area and amplitude asymmetries to beinvestigated. Results: Our results are consistent withtheoretical predictions and published observations describing convectivecollapse, and confirm this as the bright point formation process.Through degradation of the simulated data to match the spatialresolution of SOT, we show that high spatial resolution is crucial forthe detection of changing spectro-polarimetric signatures throughout amagnetic bright point's lifetime. We also show that the signaturedownflow associated with the convective collapse process tends towardszero as the radiation intensity in the bright point peaks, because ofthe magnetic forces present restricting the flow of material in the fluxtube
sj-docx-1-dst-10.1177_19322968231223726 – Supplemental material for Machine Learning Models for Prediction of Diabetic Microvascular Complications
No full textSupplemental material, sj-docx-1-dst-10.1177_19322968231223726 for Machine Learning Models for Prediction of Diabetic Microvascular Complications by Sarah Kanbour, Catharine Harris, Benjamin Lalani, Risa M. Wolf, Hugo Fitipaldi, Maria F. Gomez and Nestoras Mathioudakis in Journal of Diabetes Science and Technology</p
Observations of sausage modes in magnetic pores
No full textWe present here evidence for the observation of the magnetohydrodynamic (MHD) sausage modes in magnetic pores in the solar photosphere. Further evidence for the omnipresent nature of acoustic global modes is also found. The empirical decomposition method of wave analysis is used to identify the oscillations detected through a 4170 Å "blue continuum" filter observed with the Rapid Oscillations in the Solar Atmosphere (ROSA) instrument. Out of phase, periodic behavior in pore size and intensity is used as an indicator of the presence of magnetoacoustic sausage oscillations. Multiple signatures of the magnetoacoustic sausage mode are found in a number of pores. The periods range from as short as 30 s up to 450 s. A number of the magnetoacoustic sausage mode oscillations found have periods of 3 and 5 minutes, similar to the acoustic global modes of the solar interior. It is proposed that these global oscillations could be the driver of the sausage-type magnetoacoustic MHD wave modes in pores
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Research highlights from the 2018 European Respiratory Society International Congress: airway disease
No full textEllerman Bombs with Jets: Cause and Effect
No full textEllerman Bombs (EBs) are thought to arise as a result of photospheric magnetic reconnection. We use data from the Swedish 1-m Solar Telescope(SST), to study EB events on the solar disk and at the limb. Both datasets show that EBs are connected to the foot-points of forming chromospheric jets. The limb observations show that a bright structure in the H blue wing connects to the EB initially fuelling it,leading to the ejection of material upwards. The material moves along a loop structure where a newly formed jet is subsequently observed in the red wing of H. In the disk dataset, an EB initiates a jet which propagates away from the apparent reconnection site within the EB flame.The EB then splits into two, with associated brightenings in the inter-granular lanes (IGLs). Micro-jets are then observed, extending to500 km with a lifetime of a few minutes. Observed velocities of themicro-jets are approximately 5-10 km s, while their chromospheric counterparts range from 50-80 km s. MURaM simulations of quiet Sun reconnection show that micro-jets with similar properties to that of the observations follow the line of reconnection in the photosphere,with associated H brightening at the location of increased temperature
Stellar Surface Magneto-Convection as a Source of Astrophysical Noise. I. Multi-component Parameterisation of Absorption Line Profiles
No full textWe outline our techniques to characterise photospheric granulation as an astrophysical noise source. A four component parameterisation of granulation is developed that can be used to reconstruct stellar line asymmetries and radial velocity shifts due to photospheric convective motions. The four components are made up of absorption line profiles calculated for granules, magnetic intergranular lanes, non-magnetic intergranular lanes, and magnetic bright points at disc centre. These components are constructed by averaging Fe I magnetically sensitive absorption line profiles output from detailed radiative transport calculations of the solar photosphere. Each of the four categories adopted are based on magnetic field and continuum intensity limits determined from examining three-dimensional magnetohydrodynamic simulations with an average magnetic flux of . Using these four component line profiles we accurately reconstruct granulation profiles, produced from modelling 12 x 12 Mm areas on the solar surface, to within 20 cm s on a 100 m s granulation signal. We have also successfully reconstructed granulation profiles from a simulation using the parameterised line profiles from the average magnetic field simulation. This test demonstrates applicability of the characterisation to a range of magnetic stellar activity levels
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