Hello there!

 

I'm Mason Ng, a Postdoctoral Researcher at the McGill Department of Physics and the Trottier Space Institute at McGill.

 

I use a range of X-ray telescopes and techniques to understand the evolution and dynamics of neutron star binaries. I am also interested in multiwavelength counterparts to fast radio bursts, and large scale multiwavelength pulsar search surveys!

 

mason.ng@mcgill.ca

About Me

I am Wei Chieh Ng (Mason) (personal pronouns: he/him).

I am currently a Postdoctoral Researcher at McGill's Department of Physics and Trottier Space Institute at McGill. I was previously a graduate (PhD) student at MIT's Department of Physics and the MIT Kavli Institute for Astrophysics and Space Research. I primarily worked with Professor Deepto Chakrabarty and Dr. Herman Marshall on X-ray timing, spectroscopic, and polarimetric analyses of accreting neutron stars with a whole range of X-ray telescopes, including NICER and IXPE. I also "learnt the ropes" from titans like Dr. Paul Ray, Dr. Ronald Remillard, and Dr. Jack Steiner (plus many others along the way). I also collaborate frequently with members of the NICER Science Team and IXPE Science Team.

This website, like myself, are works in progress. Some of the design elements were inspired by Guðmundur Stefánsson. You can learn more about me and my previous endeavors in the other sections of my website.

CV

Here is the most recent version of my CV (November 2024).

This is my CV from prior to September 2018, though lightly edited to reflect my current position. I leave it here for posterity.

Current Research

My present work focuses on these areas:

  • Understanding the evolution and dynamics of interacting neutron star binaries (through X-ray timing, spectroscopy)

  • Developing and maintaining a pipeline for pulsation searches and systematic timing/spectral analysis on archival and incoming NICER data

  • Using X-ray polarimetry to understand the magnetic field morphology and accretion geometries of compact objects (with the recently-ish launched Imaging X-ray Polarimetry Explorer)

Publications (ORCID; NASA/ADS Library)

1 in Nature Astronomy. 1 in Science.

First/Co-first author

Co-author

ATels and GCN Circulars

Presentations

Talks (* = virtual)

    25 (Jul 2024) Invited Talk - Joint IXPE/NICER Workshop. Washington DC, USA. Introduction to ixpeobssim for data analysis.

    24 (Jul 2024) Seminar - Chungbuk National University. Daejeon, South Korea. Multifaceted Understanding of Accreting Neutron stars and their Environments.

    23 (Jul 2024) Seminar - Chungnam National University. Daejeon, South Korea. Exploring the Frontier of Physics with Neutron Stars.

    22 (Jul 2024) Contributed Talk - Committee on Space Research (COSPAR) Assembly 2024. Busan, South Korea. Understanding Polarization Angle Variations in Neutron Stars.

    21 (Jul 2024) Contributed Talk (Substitution) - Committee on Space Research (COSPAR) Assembly 2024. Busan, South Korea. Magnetar x-ray polarization results and implications.

    20 (Jun 2024) Seminar - INAF Osservatorio Astronomico di Roma. Monte Porzio Catone, Rome, Italy. Probing the Atoll/Z Continuum with Neutron Star Low Mass X-ray Binary 1A 1744-361.

    19 (Jun 2024) Seminar - INAF Istituto di Astrofisica e Planetologia Spaziali. Rome, Italy. Probing the Atoll/Z Continuum with Neutron Star Low Mass X-ray Binary 1A 1744-361.

    18 (Apr 2024) Contributed Talk - 21st Divisional Meeting of the High Energy Astrophysics Division. Horseshoe Bay, Texas, USA. Probing the Atoll/Z Continuum with Neutron Star Low Mass X-ray Binary 1A 1744-361.

    17 (Jan 2024) Dissertation Talk - 243rd Meeting of the American Astronomical Society. New Orleans, Louisiana, USA. X-ray and Radio Monitoring of the Neutron Star Low Mass X-ray Binary 1A 1744-361: Quasi Periodic Oscillations, Transient Ejections, and a Disk Atmosphere.

    16 *(Dec 2023) Invited Talk - Washington University in St. Louis. Multifaceted Understanding of Accreting Neutron stars and their Environments: An X-ray Polarimetric Focus.

    15 (Dec 2023) Special Astrophysics Seminar - McGill University. Berkeley, California, USA. Multifaceted Understanding of Accreting Neutron stars and their Environments: An X-ray Polarimetric Focus.

    14 (Nov 2023) Department Lunch Talk (Astronomy) - University of California, Berkeley. Berkeley, California, USA. Multifaceted Understanding of Accreting Neutron stars and their Environments: An X-ray Polarimetric Focus.

    13 (Nov 2023) Astronomy Tea Talk - California Institute of Technology. Pasadena, California, USA. Multifaceted Understanding of Accreting Neutron stars and their Environments: An X-ray Polarimetric Focus.

    12 (Nov 2023) KIPAC Tea Talk - Stanford University. Stanford, California, USA. Understanding Neutron Star Geometry through the Lens of X-ray Polarization.

    11 (Oct 2023) Seminar - NASA Goddard Space Flight Center. Greenbelt, Maryland, USA. Probing the Accretion Geometry of Neutron Stars with X-ray Polarization.

    10 (Oct 2023) Seminar - U.S. Naval Research Laboratory. Washington DC, USA. Probing the Accretion Geometry of Neutron Stars with X-ray Polarization.

    9 (Oct 2023) Seminar - University of Michigan. Ann Arbor, Michigan, USA. Probing the Accretion Geometry of Neutron Stars with X-ray Polarization.

    8 (Jan 2023) Contributed Talk - 241st Meeting of the American Astronomical Society. Seattle, Washington, USA. IXPE Observations of the Pulsar 4U 1626-67.

    7 (Dec 2022) Seminar - Nanyang Technological University. Singapore. IXPE Observations of the Neutron Star Low-Mass X-ray Binary 4U 1626-67.

    6 (Nov 2022) Seminar - JAXA/ISAS. Tokyo, Japan. IXPE Observations of the Neutron Star Low-Mass X-ray Binary 4U 1626-67.

    5 (Nov 2022) Seminar - Kyoto University. Kyoto, Japan. IXPE Observations of the Neutron Star Low-Mass X-ray Binary 4U 1626-67.

    4 *(Sep 2022) Contributed Talk - Astrophysical Polarimetry in the Time-Domain Era. Lecco, Italy. IXPE Observations of the Pulsar 4U 1626-67.

    3 (Jul 2022) Contributed Talk - Committee on Space Research (COSPAR) Assembly 2022. Athens, Greece. IXPE Observations of the Pulsar 4U 1626-67.

    2 (Aug 2016) Invited Talk - Auckland Astronomical Society. Auckland, New Zealand. Modelling the spectra of hot stars.

    1 (Apr 2016) Contributed Talk - Royal Astronomical Society of New Zealand Conference. Napier, New Zealand. Modelling the spectra of hot stars.

Posters

    5 (Jun 2024) XMM-Newton 2024 Science Workshop: The X-ray Mysteries of Neutron Stars and White Dwarfs. Madrid, Spain. Probing the Atoll/Z Continuum with Neutron Star Low Mass X-ray Binary 1A 1744-361.

    4 (Mar 2023) 20th Divisional Meeting of the High Energy Astrophysics Division. Waikōloa, Hawai'i, USA. Discovery of a 7.8 Hz QPO from the High-Intensity Outburst of Dipping NS LMXB 1A 1744-361.

    3 (Mar 2023) 20th Divisional Meeting of the High Energy Astrophysics Division. Waikōloa, Hawai'i, USA. IXPE Observations of the Pulsar 4U 1626-67.

    2 (Mar 2022) 19th Divisional Meeting of the High Energy Astrophysics Division. Pittsburgh, Pennsylvania, USA. NICER Pulsation Search and Spectroscopy of the Original Black Widow Pulsar, PSR B1957+20.

    1 (Dec 2019) Celebrating 20 Years of Chandra Science Symposium. Boston, Massachusetts, USA. Spectral Evolution of NGC 300 ULX-1.

Past Research

I previously worked on many facets of astrophysics...

In reverse chronological order,

Investigated the effects of different magnetic field strengths and configurations on the structure of the stellar atmosphere of solar-type stars.

Studied absorber kinematics of 31 OVI absorbers, which exhibited a strong halo mass dependence, where absorbers hosted by L* galaxies have the largest velocity dispersions compared with lower masses and group environments, due to a match between virial temperature and the temperature at which OVI ionization fraction is greatest. Total column densities follow the same behavior, consistent with simulations. Relative absorber--galaxy kinematics of the same sample was studied, though the mass dependence was first normalized out to account for the range of halo masses in the sample. Non-virialized motions due to outflowing gas was observed. Accreting gas signatures were not observed due to multiple line-of-sight structures that were observed, resulting in "kinematic blurring". These results indicate that OVI is not an accurate probe of baryon cycle processes.

There were two projects I carried out:

1) I performed evidence calculations with a trio of codes (CosmoMC, PolyChord, and ModeCode) on several inflationary models, most notable of which is the inflection point inflationary model. Results obtained showed that it is comparable in likelihood to quadratic potentials.

2) I also looked at quantifying the impacts of dark matter on the cosmic microwave background using the 2015 Planck likelihoods, in order to demonstrate the predictive power of dark matter. It was found that dark matter was needed at least at the $10^{100}$ level. While the physical effects of dark matter are well-understood, this quantitative calculation has not been reported in the literature.owave Background.

The results are all summarized in my Senior thesis (US)/Honours thesis (NZ/Aus).

The project involved training a computer to predict image quality from the SkyMapper telescope by considering environmental conditions and telescope configurations. The SkyMapper telescope atop Siding Spring Observatory surveys the entire Southern sky in multiple wavelengths. SkyMapper will inevitably find millions of celestial objects. One result was that the angle of rotation of the CCD camera resulted in visibly lower quality images. Once this was discovered, the SkyMapper team disabled that telescope setting.

Working with Georgie Taylor, we created over 1300 stellar atmosphere models for use in BPASS, the state-of-the-art code incorporating binary stellar systems to predict properties of stellar populations. Results of our work have contributed to the analysis of the recently announced gravitational waves, where it was concluded that similar events are more likely to occur in low-metallicity environments.

Advocacy and Outreach

Since April 2024, I have been a committee member of the newly established American Astronomical Society Working Group for International Students and Researchers in Astronomy. We are charged with supporting the international scholars, and U.S. citizens pursuing astronomical research overseas, within the AAS community. Stay tuned for updates from us!

From 2023-2024, I was the Vice-Chair of the Graduate Research and Development (GRAD) Coalition, the student arm of the GRAD Caucus in the House of Representatives, which represents over 200,000 graduate students in 32 universities over 17 U.S. states. I was responsible for executing the strategic vision set by the Chair, ultimately advocating for graduate student issues, and liaising with Congressional staffers to discuss and advance legislation addressing these issues. Our most notable accomplishment was organizing the Congressional briefing on graduate advising and mentorship in October 2023 in Washington D.C. Before that, I was the Vice-Chair of the MIT Graduate Student Council External Affairs Board (GSC EAB), and was responsible for general programming and maintaining the EAB newsletter. The GSC EAB is broadly the external arm of the MIT GSC, advocating on behalf of MIT graduate students in issues of concern to the group (e.g., climate change, research funding). We typically liaise with staffers in Congress and the Biden administration through letters and meetings. We have also sent out statements endorsing certain and relevant legislation (see here.) I have led an Astrobites article on the formation of the Graduate Research and Development (GRAD) Caucus in the House of Representatives. I have also led a delegation of 10 MIT graduate students for a two-day advocacy trip in Spring 2023 where we met with over 60 House, Senate, and committee staffer in-person meetings (plus about 10 virtual meetings) on topics from graduate student mentorship to international student issues.

I have co-led the PhysGAAP initiative, where it provides application guidance resources to prospective applicants to reduce the barriers for application to the MIT Physics PhD program, and to address the underrpresentation of students from historically excluded communities. PhysGAAP offers a one-on-one mentorship program, virtual webinars, as well as a Q&A service. More information can be found here. Please reach out to me if you would like me to speak to your student group about demystifying the graduate school admissions process! This is a free service and I especially encourage requests from schools who do not typically have students going into MIT or graduate school in physics in general.

I was also a part of MIT Astrogazers, a group of MIT astrophysics graduate students, who take out telescopes on clear nights to the public and invites them to marvel at bright celestial targets like the Moon, Saturn, and Jupiter (when they are up!)

Personal History

I come from New Zealand, though my roots stem from Malaysia, where both my parents are from. I have lived in six cities in four countries, over three continents throughout my life!

Travel

Fun graphic illustrating the countries I have visited thus far! I am always thinking about the next travel adventure!

Resources