Session F03: Astrophysics and Medical Physics

Xray to far infrared spectrum of phosphorus for astrophysical modeling

Phosphorus exists in DNA, RNA and is a basic element of life. It is abundant in the solar system. However, its presence in space has been undetectable until recently. Due to its lack of existence in astrophysical spectra the study has been limited. With the discoveries of the exoplanets the need for searching bio-signature elements, particularly phosphorus has increased significantly in order to find a clue for life. JWST is expected to obtain high resolution infrared spectra of exoplanets. We will report the wavelength regions of interest for searching the phosphorus lines and predict a spectrum ranging from x-ray to far infrared region produced by all ionization stages of phosphorus. These can help astrophysical modeling for diagnostics, abundances and determining the physical condition.   

Detection of a Disk Surrounding the Variably Accreting Young Star HBC722

\newcommand{\msun}{\mbox{M$_\odot$}}% Msun We present new 233~GHz continuum observations collected using the Atacama Large Millimeter/Submillimeter Array (ALMA) on the newly discovered FU Orionis candidate HBC722. Previous millimeter continuum data from the Submillimeter Array (SMA) failed to detect this object, ruling out the possibility of the burst being triggered by gravitational instability in a massive disk. With these data we detect HBC722 at millimeter wavelengths for the first time with a 1.3~mm continuum detection at the expected position. We use this detection to calculate a circumstellar disk mass of 0.024~\msun. With a known stellar mass of approximately 0.5~\msun, our results imply that HBC722 has a disk-to-star mass ratio of approximately 5\%, which is marginally too low for gravitational instabilities to serve as the burst triggering mechanism (such instabilities likely require disk-to-star mass ratios of 10\% or higher). However, due to uncertainties in the ALMA continuum detection, future analysis using radiative transfer modeling is required to better determine the true mass of the HBC722 disk.   

Black hole spin and Lagrange points in the restricted general relativistic three body problem

In this new era of gravitational wave astrophysics, observations have indicated the likely existence of black holes with significant spin. In order to better understand the potential imprint orbital dynamics has on the multi-messenger data, we include rotation of the primary mass to leading order in the analysis of the stability boundary pertaining to the triangular equilibrium points,L4 and L5, in the relativistic, restricted, circular three body problem. For Lagrange point stability these rotation effects are of the same order as the leading order relativistic corrections ignoring rotation and make both L4 and L5 more stable for retrograde orbital motion. (pub. as. Phys. Rev. D. 102, 024052 (2020))   

Thermodynamics of pair black holes in a static deSitter spacetime with matter

Most multi-blackhole static spacetime solutions make use of special (extremal) limits, symmetries and non-gravitational fields. We analyze the semiclassical thermodynamics of static solutions we have found consisting of antipodal uncharged black hole pairs of different masses in 3$+$1 dimensional deSitter space supplied with regular matter in stable orbits. These solutions provide a closed, static instances of ordinary Einstein gravity with which to address aspects of non-stationary semiclassical gravitational effects (e.g. the Hawking process).   

Characterizing the simulated anomalous diffusion of proteins in relation to the nanoporous structure of extracellular matrix-relevant hydrogels

Local drug delivery requires therapeutics to diffuse through the nanoporous structure of the extracellular matrix. To enable the efficient delivery of drugs, both the structure of this hydrogel environment and the diffusion of the drug must be understood. We simulated fluorescence microscopy data of BSA diffusing in binarized images of polyacrylamide at various concentrations. Conventional methods are unable to quantify both nanoscale structure and diffusion, but we were able to overcome these limitations with a correlation technique known as ``fluorescence correlation spectroscopy super-resolution optical fluctuation imaging'' or ``fcsSOFI,'' which can quantify local anomaleity and diffusion coefficients, along with the size, shape, and frequency of nanopore structures. In conditions based on experimental sample and microscope parameters, we observed subdiffusive behavior of BSA in smaller pores. Delauney triangulation was applied to calculate pore sizes, and showed agreement with the ground truth. Combining the characterizations of pore sizes and local anomaleity allowed us to relate the subdiffusivity of simulated proteins with pore size. These findings can help inform drug-delivery applications where nanoparticle therapeutics must diffuse through the extracellular matrix.   

Mathematical Models for Living Forms in Medical Physics Submodel 1: The Information Processing from Teeth to Nerves

This talk continues the presentation at APS March Meeting 2019 and APS April Meeting 2019. In this part of the project the first submodel is presented; The information processing from teeth to the nerves. Information processing is modeled via p-waves passing through the tooth layers enamel and dentin. Odontoblasts located in the liquid in the tubules of the tooth dentin layer perform finally the transformation into electrical information (an electrical signal) that passes along nerves. The presentation was scheduled for the APS March Meeting 2020 Conference (the APS March Meeting 2020 Conference got canceled because of Covid-19), the presentation was given at the APS April Meeting 2020 Conference.