Publications

View Publication

Observation of Neutron Star-Low-Mass X-ray Binary 4U 1728-34 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals an X-ray polarization degree of ~2%, with no significant polarization in the radio band. This suggests the presence of a Comptonized component of the Neutron star geometry such as a boundary layer. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

Observation of Neutron Star-Low-Mass X-ray Binary GX 349+2 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals a polarization degree of ~1%. This paper reports the first IXPE observation of the source. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

View Publication

Observation of X-ray Pulsar 4U 1538‑52 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals a marginal polarization detection of ~3% and potential evidence of energy-dependent polarization, providing constraints on measurements of magnetic obliquity (~30°) and spin position angle (~19°) of the source. This paper reports the first IXPE observation of the source. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper and supervised spectropolarimetric analysis conducted by R. Kelly.

View Publication

Simulations of the X-ray spectropolarimetric properties of Neutron star populations such as magnetars and X-ray dim isolated Neutron stars show evidence of a proton-cyclotron absorption feature and spectropolarimetric evidence of quantum electrodynamic effects observable by a soft X-ray polarimeter like the sounding rocket mission REDSoX (or its proposed orbital successor GOSoX.) I provided REDSoX and GOSoX instrumental expertise for this paper.

View Publication

View Publication

Observation of Neutron Star-Low-Mass X-ray Binary Z-source GX 340+0 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals polarization of the normal branch aligned with previously reported polarization in the horizontal branch with a lower polarization degree. This paper reports the first IXPE observation conducted across the full Z-track. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper. I also completed branch-resolved polarimetry for this paper.

View Publication

Observation of bright atoll Neutron Star-Low-Mass X-ray Binary Serpens X-1 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope suggests an upper limit of 2% polarization of the source. The observation includes the first X-ray polarimetry observations of type-1 X-ray bursts and puts an upper limit of 80% polarization on these X-ray bursts. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

View Publication

Observation of bright Neutron Star-High-Mass X-ray Binary SMC X-1 with Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals significant polarization across three separate observations of the source with time-dependent changes to both polarization degree and angle over the three observations. This polarization is possibly caused by the winds of the accretion disk scattering light while the accretion disk precesses. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

Multi-Wavelength study of Neutron Star low-mass X-ray binary (NS-LMXB) GX 340+0 finds significant energy-dependent polarization and high-frequency radio emission. I conducted X-ray data analysis using two space telescopes for this paper—the Imaging X-ray Polarimetry Explorer (IXPE) and the Nuclear Spectroscopic Telescope Array (NuSTAR). I conducted polarization PCUBE analysis of IXPE data and performed light curve extraction/hardness-intensity diagram plotting from NuStar data.

View Publication

Observation of the Active Galactic Nucleus (AGN) NGC 1068 by the Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals the AGN’s polarization angle is perpendicular to the direction of the radio jet. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

Observation of Type-I X-Ray Burster GX 13+1 with the Imaging X-Ray Polarimetry Explorer (IXPE) space telescope reveals significant polarization and rotation of the polarization angle by approximately 70 degrees. I conducted polarization PCUBE analysis and spectropolarimetric analysis of IXPE data for this paper.

View Publication

NASA report on SPOCS experiment “Characterizing Antibiotic Resistance in Microgravity Environments” (CARMEN) growing two antagonistic strains of bacteria Staphylococcus aureus and Pseudomonas aeruginosa for 30 days in microgravity aboard the International Space Station to study antibiotic resistance in these space-grown bacteria.

View Publication

White paper outlining recommendations by the NASA GeneLab Microbe Analysis Working Group for future directions of space microbiology. The paper discusses the CARMEn experiment as an example of the recommended systems approach to space microbiology utilizing observational data for rigorous hypothesis and model testing.

View Publication

AIAA Sci-Tech 2021 Conference Paper on sharp-edge detection and removal for astronaut safety aboard the International Space Station-developed at Columbia University and tested at NASA’s Neutral Buoyancy Laboratory. Won 1st place student team presentation at Sci-Tech 2021.

AAS contributed talk in which I introduced the NASA sounding rocket mission REDSoX which will perform the first X-ray spectropolarimetric measurements below 1 keV. I overviewed progress made toward optics shell replication, grating efficiency testing, and detector engineering model testing, and introduced the proposed NASA Pioneer orbital successor to REDSoX—GOSoX. (Anchorage, Alaska).

View

AAS contributed talk in which I showed the results of applying a new method of maximum likelihood estimation to Imaging Polarimetry Explorer (IXPE) telescope polarimetry data from the Neutron star-low-mass X-ray binary GX 13+1. My results using this method agree with the standard method (PCUBE), and I show that this method can produce an agreeing polarization angle rotation rate to that found using PCUBE without the need for manually binning the data. This method also utilizes a Bayesian nested sampling appraoch which allows for more physically-motivated results. (National Harbor, Maryland).

View Slides, View Video

Virtual contributed talk given at NASA’s Physics of the Cosmos Early Career Workshop describing two NASA technology development projects I’ve been involved with—Characterizing Antibiotic Resistance in Microgravity Environments (CARMEn) and the Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX).

Abstract: The Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX) is a NASA sounding rocket mission conducting X-ray spectropolarimetry below 1 keV for targets such as the blazar Mrk 421. The instrument is scheduled for launch in late 2027 and will utilize a focusing Wolter I optic, Critical Angle Transmission (CAT) gratings, and laterally graded multilayer mirrors at Brewster’s angle to perform spectropolarimetry in the energy range of 0.2–0.4 keV. In this talk I discussed my current work on the REDSoX mission and related it to my previous work developing the NASA mission Characterizing Antibiotic Resistance in Microgravity Environments (CARMEn), a 30-day ISS mission studying bacterial antibiotic resistance in space, to highlight similarities and differences in the technology development process for space-based NASA missions across different size scales.

View

COSPAR contributed talk in which I showed the results of applying a new method of maximum likelihood estimation to Imaging Polarimetry Explorer (IXPE) telescope polarimetry data from the Neutron star-low-mass X-ray binary GX 13+1. My results using this method agree with the standard method (PCUBE), and I show that this method can produce an agreeing polarization angle rotation rate to that found using PCUBE without the need for manually binning the data. This method also utilizes a Bayesian approach which allows for more physically-motivated results. (Busan, South Korea).

View

Invited COSPAR talk on behalf of Alan Garner overviewing the progress made on the Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX). I overview the instrument design including a multilayer mirror and custom-manufactured diffraction gratings and present successful shake-test results of the grating. (Busan, South Korea).

View

Pre-launch oral presentation at Kennedy Space Center (Brevard County, FL) describing the science goals and engineering design of the CARMEn mission flown to the ISS on SpaceX CRS-24.

Poster Presentation for NSRC 2020 (Broomfield, CO) on sharp-edge detection and removal for astronaut safety aboard the International Space Station-developed at Columbia University and tested at NASA’s Neutral Buoyancy Laboratory.

View

Poster presentation at Large Synoptic Survey Telescope (LSST) Workshop (Tucson, AZ) on modeling distant galaxies with near-field spectra of Milky Way stars in the SDSS MaStar catalog.

View

View