Welcome

I am an observational cosmologist that designs and builds novel instruments to improve our understanding of the properties and evolution of the universe. I work as Assistant Professor at the University of Toronto in the Dunlap Institute and the David A. Dunlap Department of Astronomy and Astrophysics.

Research

My research work drives the development of modern and next-generation radio telescopes that require unprecedented levels of signal processing power to unlock their scientific potential, including the world’s largest radio correlator and the world’s most powerful radio transient detector. Furthermore, I analyze and interpret the data from these instruments to advance our knowledge of the universe, from its expansion history to the nature of the radio transient sky.

See below for some of my recent and ongoing projects. My complete list of publications can be found on ADS. You can can also check my CV for additional information.

The CHIME telescope

Dark energy is a property attributed to the large-scale universe in order to explain its accelerated expansion. Understanding its nature is one of the biggest challenges of cosmology today, with profound implications for fundamental physics and our understanding of the universe. I work in the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a novel interferometer radio telescope designed to study the expansion history of the universe and probe the nature of dark energy. CHIME is mapping the large-scale structure of neutral hydrogen gas in the universe by directly detecting its redshifted 21 cm radiation. We will use that information to study the epoch when dark energy generated the transition from decelerated to accelerated expansion of the universe.

I have been part of the CHIME collaboration since the telescope's conception and have been involved with multiple aspects of the experiment: from instrument design and construction to data analysis. Now that CHIME is performing the largest volume astronomical survey to date, my work is centered on the development of calibration and data analysis techniques to characterize the instrument and separate the weak 21 cm signal from bright astrophysical contaminants.

CHIME consists of four 20 m x 100 m cylindrical reflectors instrumented with a total of 1024 dual-polarization antennas operating in the 400-800 MHz band. The cylinders are fixed with no moving parts, so CHIME surveys the northern half of the sky every day as the earth rotates (photo credit: Nolan Denman).

CHIME is located at the Dominion Radio Astrophysical Observatory (DRAO) near Penticton, B.C., Canada.

First antennas installed on the CHIME Pathfinder, the predecessor and technology testbed of CHIME.

The CHIME correlator

Mapping the universe with the 21 cm line requires substantial signal processing capabilities in order to probe large volumes of the universe rapidly. I was a member of the team that designed and commissioned the state-of-the-art backend that implements the CHIME high-bandwidth radio correlator, the world’s largest of its kind.

CHIME has no moving parts, but it can be pointed digitally at different sky locations by combining in real time the signals from all its antennas. The correlator continuously processes more than 13 terabits of data every second (equivalent to all of Canada's internet traffic) and performs more than 800 trillion operations every second in order to enable this all-digital telescope.

Custom-built ICE motherboards implement the digitization, F-engine, and networking engine of the CHIME correlator. The correlator requires 128 ICE motherboards to process the enormous amount of data generated by CHIME.

The CHIME F-engine digitizes and channelizes the signals from the 1024 CHIME antennas. It also implements the high-bandwidth network that re-arranges the data before sending it to the spatial correlator.

The CHIME spatial correlator performs more than 800 trillion operations per second and generates data products for a variety of backends specialized in cosmology and radio transient science (photo credit: Nolan Denman).

CHIME/FRB Outriggers

CHIME is also an excellent platform to study the radio transient sky, including the mysterious Fast Radio Bursts (FRBs). FRBs are short-duration pulses of radio light of unknown extragalactic origin. Even though thousands of FRB events occur over the full sky every day, their detection with traditional radio telescopes is very challenging due to the random, non-repeating nature of the vast majority of bursts. Thanks to its unique design and powerful correlator, CHIME has become the world’s leading FRB detector, finding hundreds of FRBs each year.

I am also working on the design and construction of CHIME/FRB Outriggers, a set CHIME-like telescopes separated by continental-scale distances that will work together as an enourmous radio telescope several thousands of kilometers across, providing precise localizations for FRBs detected by CHIME. These localizations will provide unique information about the physical environments and emission mechanisms that generate FRBs and allow their use as cosmological probes.

CHIME is the world's most powerful FRB detector, finding hundreds of events each year. While it took a decade to collect the first sample of 50 FRBs using traditional telescopes, CHIME detected 13 within the first few weeks of its pre-commissioning phase in 2018.

CHIME detects many FRBs but does not have the ability to localize their host galaxies. CHIME/FRB Outriggers consists of CHIME-like telescopes situated across North America and working with CHIME to localize hundreds of FRBs each year using very-long-baseline interferometry (VLBI) .

CHORD

CHIME/FRB Outriggers represents the first phase of the Canadian Hydrogen Observatory and Radio-transient Detector (CHORD), a next-generation instrument that will complement CHIME and the cylindrical outriggers with large arrays of dish telescopes instrumented with novel ultra-wideband antennas, significantly improving CHIME’s angular resolution and sensitivity for both cosmology and radio transient science.

CHORD will consist of a core telescope array with 512 ultra-wideband dishes and outrigger stations equipped with 64 dishes. As shown in this conceptual illustration, the CHORD core will be located adjacent to CHIME at Dominion Radio Astrophysical Observatory (DRAO).

CHORD prototype telescope with ultra-widebad antenna mounted at the focus.

About me

I am from Medellín, Colombia, where I studied Electronic Engineering at Universidad de Antioquia. After that I moved to Canada to study Honours Mathematics and Physics at McGill University. I received my PhD in Physics from McGill University in 2018, working in the McGill Cosmology Instrumentation Laboratory with Matt Dobbs. After that, I was a Kavli Fellow at the Massachusetts Institute of Technology in the Kavli Institute for Astrophysics and Space Research. I joined the Dunlap Institute and the David A. Dunlap Department of Astronomy and Astrophysics at University of Toronto as Assistant Professor in 2022.

Contact

Dunlap Institute for Astronomy and Astrophysics
University of Toronto
50 St. George Street, Toronto, ON M5S 3H4, Canada

Email: juan.menaparra@utoronto.ca