EDUCATION

  • Doctor of Philosophy, Astronomy and Astrophysics, Univ. of Toronto (Sep 2018 - Aug 2023)

  • Master of Engineering, Electrical and Computer Engineering, Univ. of Toronto (Sep 2016 - June 2018)

  • Bachelor of Science, Electrical and Computer Engineering, Univ. of Manitoba (Sep 2010 - June 2015)

RESEARCH INTERESTS

  • Physical cosmology, large-scale structure

  • Weak gravitational lensing

  • Multi-wavelength observations of galaxy clusters

  • Exoplanets

  • Astronomical instrumentation

    • Low-cost balloon-borne and small-satellite instruments in the era of New Space

    • Near-ultraviolet to near-infrared CMOS/CCD detector characterization

    • Radio astronomy instrumentation

RESEARCH EXPERIENCE

  • Graduate Research: Instrument development and science flight of the Superpressure Balloon-Borne Imaging Telescope (SuperBIT)

    • Department of Astronomy and Astrophysics, University of Toronto (May 2019 - Present)

  • Abstract: Galaxy clusters are the largest gravitationally bound objects in the Universe. The distribution of galaxy clusters as a function of mass and redshift is highly sensitive to the amount of dark energy and dark matter in the Universe. SuperBIT is a near-ultraviolet to near-infrared balloon-borne imaging telescope with a 0.5 meter diameter primary mirror. With a 0.12 square degree field of view (~ 40 times the Advanced Camera for Surveys on the Hubble Space Telescope) and a high resolution of ~ 0.2 - 0.3 arcseconds per pixel, SuperBIT will map the dark matter distribution of up to 100 galaxy clusters using weak gravitational lensing. SuperBIT will launch on a NASA superpressure balloon into the stratosphere (~35 km above sea level) for its long-duration science flight in the spring of 2023 from Wanaka, NZ. My graduate research work has been broad and consisted of the instrumentation, analysis, calibration, testing, and integration of SuperBIT, under the supervision of Dr. Barth Netterfield.

SuperBIT before launch during its engineering test flight from the Timmins Stratospheric Balloon Base (Sep 2019)

  • Graduate Research: Multi-frequency observations of galaxy clusters and filaments with the Atacama Cosmology Telescope and the Planck satellite

    • Department of Astronomy and Astrophysics, University of Toronto (June 2021 - Present)

  • Abstract: The Atacama Cosmology Telescope (ACT) is a six-meter diameter telescope located on Cerro Loco in the Atacama Desert in Chile. ACT makes high sensitivity observations of the cosmic microwave background (CMB), the relic radiation from the Big Bang to: (i) measure the cosmological parameters that describe the very early Universe, and (ii) to measure the properties of distant clusters of galaxies and their environments. When photons from the CMB pass through a galaxy cluster, the hot electrons in the cluster boost the energy of the photons, leading to the thermal Sunyaev–Zeldovich effect. The bulk motion of a galaxy cluster can also affect the CMB photons (kinematic Sunyaev–Zeldovich effect). Under the supervision of Dr. Adam D. Hincks, I am using multi-frequency maps from ACT and the Planck satellite to model the thermal, kinematic, and relativistic Sunyaev–Zeldovich effects from galaxy clusters and their environments.

Observations of the cosmic microwave background from the Planck satellite (left), ACT+Planck (middle), and ACT only (right). Reference: Naess et al. (2021)

Observation of the galaxy cluster pair system (Abell 399 and Abell 401) with the ACT telescope. The bridge connecting the two cluster is a cosmic filament. Reference: Hincks et al. (2021)

  • Graduate Research: A low-cost ultraviolet-to-infrared absolute quantum efficiency characterization system of detectors

    • Department of Astronomy and Astrophysics, University of Toronto (June 2021 - June 2022)

  • Abstract: I developed a low-cost ultraviolet to infrared absolute quantum efficiency detector characterization system using commercial off-the-shelf components. The key components of the experiment include a light source,a regulated power supply, a monochromator, an integrating sphere, and a calibrated photodiode. In the paper, I provide a step-by-step procedure to construct the photon and quantum efficiency transfer curves of imaging sensors. The paper present results for the GSENSE 2020 BSI CMOS sensor and the Sony IMX 455 BSI CMOS sensor. A primary goal of the paper is to be a useful guide for other research groups trying to develop a similar setup. Reference: Gill et al. (2022), SPIE Astronomical Telescopes and Instrumentation, Conference 12191: X-ray, Optical, and Infrared Detectors for Astronomy X, Paper Number: 12191-39 (Montreal, July 2022).

Absolute quantum efficiency of the Sony IMX 455 CMOS sensor (around the QHY600m pro camera) measured using my detector characterization setup. For procedure, parts list, and setup description, see Gill et al. (2022).

Photon transfer curve of the Sony IMX 455 CMOS sensor (around the QHY600m pro camera) measured using my detector characterization setup. For procedure, parts list, and setup description, see Gill et al. (2022).

  • Graduate Research: Instrument upgrade for the 10-meter Algonquin Radio Observatory for Fast Radio Burst localization

    • Department of Astronomy and Astrophysics, University of Toronto (Sep 2018 - April 2019)

  • Abstract: I worked on upgrading the hardware infrastructure of the 10-meter radio telescope called the Algonquin Radio Observatory (ARO) under the supervision of Dr. Keith Vanderlinde and Dr. Mubdi Rahman. The primary science goal of the telescope is to use Very Long Baseline Interferometery (VLBI) to localize Fast Radio Bursts (FRBs) detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Localizing the FRB to the host galaxy can then allow for multi-wavelength observations of the galaxy to better understand the physical mechanism of FRBs. The project was a successful proof-of-concept and demonstrated that localization of 200 milliarcseconds can be achieved. See Cassanelli et al. (2022) for further details.

The 10-m Algonquin Radio Observatory. Reference: Cassanelli et al. (2022)

  • Summer Research: Prospects for Wideband VLBI Correlation in the Cloud for the Event Horizon Telescope

    • Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts (May - August 2018)

  • Abstract: The Event Horizon Telescope (EHT) is telescope array consisting of a global network of radio telescopes. The EHT project correlates data from using Very Long Baseline Interferometry (VLBI) from the radio telescopes to achieve high angular resolution images of supermassive black holes at the centers of galaxies. The data size of EHT observations is ~ petabyte scale, making the processing and storage of the data a challening process. My project consisted of investigating the use of cloud computing both for VLBI correlation computation and for data storage for Big Data projects like the EHT (under the supervision of Dr. Jonathan Weintroub and Dr. Sheperd Doeleman). The details of the work can be found in Gill et al. (2019).

The image of supermassive black hole at the center of M87 gathered by the Event Horizon Telescope. Reference: The Event Horizon Telescope Collaboration (2019)

  • Summer Research: A Study of the Compact Water Vapor Radiometer for Phase Calibration of the Karl G. Jansky Very Large Array

    • National Radio Astronomy Observatory, Socorro, New Mexico (May - August 2017)

  • Abstract: Fluctuations in precipitable water vapor in the atmosphere cause fluctuations in atmospheric brightness emission, which are proportional to phase fluctuations of the astronomical signal seen by a radio interferometer. Water vapor radiometry consists of using a radiometer to measure variations in the atmospheric brightness emission to correct for these phase fluctuations in the data. Under the supervision of Mr. Robert Selina and Dr. Rick Perley, my project consisted of characterizing a 5-channel Water Vapor Radiometer, specifically the channel isolation, gain stability, temperature stability, and the dynamic range. The results of this work can be found in Gill et al. (2018) (also EVLA Memo 203).

Passband measurements of the five channels of the Water Vapor Radiometer.

  • Summer Research: Extended X-ray emission associated with the radio lobes and the environments of 60 radio galaxies

    • Department of Physics and Astronomy, University of Manitoba (May - August 2016)

  • Abstract: This paper studied the faint, diffuse extended X-ray emission associated with the radio lobes and the hot gas in the intracluster medium environment for a sample of radio galaxies. We used shallow (∼10 ks) archival Chandra observations for 60 radio galaxies (7 FR I and 53 FR II) with 0.0222 ≤ z ≤ 1.785 selected from the 298 extragalactic radio sources identified in the 3CR catalog. We used Bayesian statistics to look for any asymmetry in the extended X-ray emission between regions that contain the radio lobes and regions that contain the hot gas in the ICM. In the Chandra broadband (0.5−7.0 keV), which has the highest detected X-ray flux and the highest signal-to-noise ratio, we found that the non-thermal X-ray emission from the radio lobes dominates the thermal X-ray emission from the environment for ∼77% of the sources in our sample. We found that the relative amount of on-jet axis non-thermal emission from the radio lobes tends to increase with redshift compared to the off-jet axis thermal emission from the environment. This suggests that the dominant X-ray mechanism for the non-thermal X-ray emission in the radio lobes is due to the inverse Compton upscattering of cosmic microwave background seed photons by relativistic electrons in the radio lobes, a process for which the observed flux is roughly redshift independent due to the increasing CMB energy density with increasing redshift. For further details, see Gill et al. (2021). I did this work under the supervision of Dr. Christopher O’Dea and Dr. Stefi A. Baum.

R is a measure of whether there is higher X-ray emission in regions in radio galaxies that contain radio lobes (R > 1) or regions in the hot environment of radio galaxies that do not contain radio lobes (R < 1). In the broad (0.5 - 7 keV) band of Chandra, we found that R increases as a function of redshift. This suggests that the on-jet X-ray emission is due to the inverse Compton scattering of Cosmic Microwave Background photons by hot electrons, a non-thermal process for which the observed flux is roughly redshift independent due to the increasing CMB energy density with redshift. Reference: Gill et al. (2021)

  • Summer Research: Study of the energy efficiency of a pelton generator (Baden-Wurttemberg Foundation Scholarship)

    • Hochschule Ravensburg Weingarten, Germany (May - August 2014)

PROFESSIONAL EXPERIENCE

  • Intern: United Nations Headquarters, Manhattan, New York (Oct 2015 - Feb 2016)

  • Junior Fellow: Engineers Without Borders, Ghana (May - August 2013)

PUBLICATIONS (FIRST AUTHOR)

  • Gill, A., et al. A Low-Cost Ultraviolet-to-Infrared Absolute Quantum Efficiency Characterization System Of Detectors, SPIE Astronomical Telescopes and Instrumentation, 12191-39, June 2022.

  • Gill, A., Boyce, M. M, O’Dea, C. P, Baum, S. A., Kharb, P., Campbell, N., Tremblay, G. R., Kundu, S., Extended X-Ray Emission Associated with the Radio Lobes and the Environments of 60 Radio Galaxies, ApJ 912 88. May 2021.

  • Gill, A., Benton, S. J., Brown, A. M., Clark, P., Damaren, C. J., Eifler, T., Fraisse, A. A., M., Galloway, M. N., Hartley, J. W., Holder, B., Huff, E. M., Jauzac, M., Jones, W. C., Lagatutta, D., Leung, J., Li, L., Luu, T., Massey, R. J., McCleary, J., Mullaney, J., Nagy, J., Netterfield, C. B., Redmond, S., Rhodes, J. D., Romualdez, L. J., Schmoll, J., Shaaban, M., Sirks, E., Sivanandam, S., Tam, S. Optical Night Sky Brightness Measurements From The Stratosphere. AJ 160 266. Nov 2020.

  • Gill, A., Blackburn, L., Roshanineshat, A., Chan, C. K., Doeleman, S., Johnson, M., Raymond, A. W., Weintroub, J. Prospects of Wideband VLBI Correlation in the Cloud. PASP 131 124501. Oct 2019.

  • Gill, A., Selina, R., Butler, B., Jackson, J., Perley, R., Hennies, C., Koski, W., Peck, G., Grammer, W., Willoughby, B. A Study of the Compact Water Vapor Radiometer for Phase Calibration of the Karl G. Jansky Very Large Array. National Radio Astronomy Observatory EVLA Memo Series, EVLA Memo 203. July 2018. arXiv:1807.01690.

PUBLICATIONS (CO-AUTHOR)

  • Shaaban, M., Gill, A. et al., Weak Lensing in the Blue: A Counter-intuitive Observational Strategy for Stratospheric Imaging, To be submitted to ApJ, Fall 2022.

  • McCleary, J. et al. (co-author as part of SuperBIT collaboration), Forecasting Cosmology Performance of SuperBIT 2022, To be submitted to ApJ, Fall 2022.

  • Radiconi, F., Vacca, V., Battistelli, E., Bonafede, A., Capalbo, V., Devlin, M., Di Mascolo, L., Feretti, L., Gallardo, P., Gill, A., Giovannini, G., Govoni, F., Guan, Y., Hilton, M., Hincks, A., Hughes, J., Iacobelli, M., Isopi, G., Loi, F., Moodley, K., Mroczkowski, T., Murgia, M., Orru, E., Paladino, R., Partridge, B., Sarazin, C., Orlowski S, J., Sifon, C., Vargas, C., Vazza, F., Wollack, E. J. The Thermal And Non-Thermal Components Within And Between Galaxy Clusters Abell 399 And Abell 401, submitted to MNRAS, June 2022.

  • Cassanelli, T. et al. (co-author as part of the CHIME/FRB collaboration), Localizing FRBs Through VLBI With The Algonquin Radio Observatory 10-m Telescope, AJ, 163, 65, Jan 2022.

  • Sirks, E. et al. (co-author as part of SuperBIT collaboration), Download By Parachute: Retrieval Of Assets From High Altitude Balloons, JINST, 15, P05014, May 2020.

  • Romualdez, L. J. et al. (co-author as part of SuperBIT collaboration), Robust Diffraction-Limited NIR-To-NUV Wide-Field Imaging From Stratospheric Balloon-Borne Platforms – SuperBIT Science Telescope Commissioning Flight And Performance, RSI, 92, 0019901, Nov 2019.

  • Josephy, A. et al. (co-author as part of the CHIME/FRB collaboration), CHIME/FRB Detection Of The Original Repeating Fast Radio Burst Source FRB 121102, ApJL, 882, L18, Sep 2019.

  • Co-author as part of the CHIME/FRB collaboration, A Second Source Of Repeating Fast Radio Bursts, Nature, 566, 235-238, Jan 2019.

TEACHING EXPERIENCE

  • Teaching Assistant: AST 101: The Sun and Its Neighbours, Fall 2018, 2020, 2021, 2022.

  • Teaching Assistant: AST 121: Origin and Evolution of the Universe, Winter 2021.

  • Teaching Assistant: AST 201: Stars and Galaxies, Winter 2018, 2020, 2022.

  • Instructor: Dunlap Institute Virtual Summer School, Summer 2021. I developed and ran the Optical Instrumentation Jupyter Notebook based virtual lab for students from around the world.

  • Instructor: Dunlap Institute Summer School, Summer 2019. I helped run the X-ray detector lab for students from around the world.

HONORS AND AWARDS

  • Queen Elizabeth II / Walter John Helm Graduate Scholarship in Science & Technology (2021, 2022)

  • Mary And Ron Martin Graduate Fellowship in Astrophysics (2020, 2021)

  • University of Toronto School of Graduate Studies Conference Grant (2018, 2019)

  • USNC-URSI 2018 Travel Fellowship for National Radio Science Meeting (2018)

  • University of Toronto Electrical and Computer Engineering Fellowship (2016, 2017)

  • University of Manitoba Emerging Leader Award (2014, 2015)

  • Baden-Wurttemberg Foundation Scholarship (2014)

SuperBIT pointing in the High Bay at the NASA Columbia Scientific Balloon Facility during its integration campaign (Fall 2022).