Research

Next Generation Very Large Array

The Next Generation Very Large Array (ngVLA) is an upcoming ground-based radio telescope array, improving on the sensitivity and spatial resolution of VLA and ALMA. With construction planned for 2025, research is still being done on how to best optimize the design of the array configuration to meet a variety of science goals, including observations of nebulae, galaxies, stellar photospheres, and black holes (for "Key Science Goals," see Bolatto et al. 2017).

The current ngVLA configuration (Credit: NRAO).

My research has focused on comparing current and proposed ngVLA configurations and evaluating their performance for imaging stellar photospheres, as well as comparing results using different imaging methods. Specifically, I have focused a different stellar models for asymptotic giant branch (AGB) and red supergiant (RSG) stars such as Betelgeuse. I began this research in 2021 under the mentorship of Dr. Kazu Akiyama and Dr. Lynn D. Matthews at MIT's Haystack Observatory. We published a memo on comparing the previous (current at the time) ngVLA configuration, called Rev. C, with the current (proposed at the time) Rev. D configuration (Petretti et al. 2021).


Imaging results for four different stellar photosphere models with the Rev. C and Rev. D configurations. The groundtruth images are also shown in the top row. The four stellar photosphere models represent an AGB star (Freytag), an RSG star (Chiavassa), and two disks of uniform brightness with superimposed surface features (UniDisk222pc and Unidisk1kpc) (Petretti et al. 2021).

We are currently finishing work on comparing results of imaging the same stellar photosphere models with the Rev. D configuration and two new proposed configurations (Walker 2022, Carilli 2022).