Meet our Scientists

Featured This Month:

Daan Meerburg

By training I am a theoretical physicist, with roots in the string group in Amsterdam. Working on models of the early Universe I soon learned that model space is enormous and that our only hope of ever testing these models is by carefully studying the relic afterglow from the Big Bang. After my PhD I moved to Princeton, which of course has one of the densest populations of CMB experts and pioneers. From then on my interest started to move towards understanding how we can optimally extract data from the CMB to learn about the earliest moments in our Universe.

It is fascinating to realise that we live in this unique moment in time, where over only a short period in the history of our existence we have learned so much about the origin and the evolution of the Universe. If we can increase our understanding of the cosmos as much as we have in the first 35 years of my life, it’s hard to imagine how many discoveries we will make in the next decades. It is really exciting to me to participate in building an experiment starting from an idea and using this experiment to look back in time, while being part of a large collaboration.

My current role in SO is to lay the foundation for a pipeline that can extract higher order correlation function in the CMB, with an emphasis on those that are sourced by primordial gravitational waves. These relics could be a direct tracer of string theory, the unifying framework in physics. Specifically, some models show that new massive degrees of freedom (particles), which are naturally predicted in string theory, could source deviations from primordial Gaussianity. These particles typically have a spin associated with it and this could result in non-Gaussianities that couple gravitational waves to density waves. SO is uniquely positioned to constrain these interactions, as forecasts show that ideally an experiment is required to have excellent polarisation sensitivity, measurements down to small scales, and a large sky fraction. These are practically the experimental qualities of the SO observatory.

Ultimately, I hope our collaboration will be the first to detect primordial gravitational waves and, as such, establish an era of primordial gravitational wave physics very similar to how gravitational waves have recently caused a paradigm shift in the low redshift Universe.

Eve Vavagiakis

I’m a PhD candidate working in Michael Niemack’s group at Cornell University in Ithaca, NY. Growing up, I was always interested in what I thought of as the two “final frontiers”: the brain, and space. My interest in astronomy led me to pursue an undergraduate degree in physics at Cornell, where I was lucky enough to knock on Gordon Stacey’s door during my first year, allowing me to get started on research in the Astronomy Department. My undergraduate research focused on the mechanical design of cryogenic astronomical instrumentation. As I progressed through my coursework and learned more about various fields of study, my interest in cosmology grew. What could be better than studying all of space at one time?

Excited by the study of the universe as a single system, I applied for physics graduate school and began my research in experimental cosmology. I currently work as a part of three different experiment collaborations: the Atacama Cosmology Telescope, CCAT-prime, and Simons Observatory. Being able to be a part of efforts like the Simons Observatory from day one has been an exceptional experience as a graduate student. It’s been great to be able to see how such an ambitious experiment gets off the ground thanks to the collaborative effort of so many talented people with various complementary sets of experience and skills. One aspect of experimental cosmology that surprised me when I first started was how interpersonal it is. The popular culture image of the lone scientist working in the basement lab in the white coat definitely doesn’t hold true here. Because we all need to work together to build such massive instruments and systems, there are constant email chains, meetings, telecons, and opportunities to travel and meet fellow scientists.

My body of work has included both instrumentation and analysis, which I enjoy because it’s interesting to think about these experiments from the initial design of the instrument and how the detectors function, all the way to the final products: the images we take, and the science that we can do with them. I work on cryogenics design, thinking about how to build systems that are able to cool detectors way down to near absolute zero; data analysis, using maps of the Cosmic Microwave Background (CMB - the oldest light in the universe) to study how galaxy clusters change that light as it passes through them; and detector testing, looking at the behavior of the superconducting devices we use as the pixels of our camera and the readout systems for our data. For Simons Observatory, I’m focusing on how sensitive our devices are to magnetic fields, and considering how we can protect our experiment from fields that could negatively affect our maps of the CMB.

Beyond research, I’m active in outreach activities that inform the public about the awesome work that’s being done in experimental cosmology. As part of this effort, I help run the social media feeds for Simons Observatory. Each week, a different person takes over the accounts and shares interesting photos and updates from their institution. It’s a great way to step into another scientist’s shoes for the day. If you haven’t already, follow us on Twitter and Facebook!

Outside of work, I love to get out of my head and into my body by lifting weights, doing yoga, running and hiking along the beautiful Ithaca gorges and waterfalls, and most recently, taking aerial classes at the local circus school. I also take advantage of the amazing local ingredients the Finger Lakes region has to offer, going to the Farmers’ Market every week during the summer to cook and bake up a storm.

Alexander van Engelen

I am a senior reseach associate at the Canadian Institute for Theoretical Astrophysics in Toronto, Canada.

The most exciting thing about the Simons Observatory to me is the fact that we can use it to study the Universe throughout all of cosmic history. Since light travels at the speed of light, as we look farther out in the Universe, we are looking back in time. Nearby, the SO will provide images of our galaxy, showing clouds of dust. Going beyond our own galaxy, the images will contain radio jets emerging from around black holes at the centers of other galaxies; bright spots from galaxies in the early universe where stars are being formed; and dark shadows corresponding to faraway clusters of galaxies, the most massive objects in the Universe. Looking farther, we expect to see the signatures of moving gas as the gas is being percolated due to the light from some of the ealiest stars. Even farther back, we will make some of the most precise images of the cosmic microwave background, giving us a unique view into the time shortly after the big bang when the Universe was extremely smooth and hot.

For each of these cases, we will be able to compare what we see in these images with what we might expect based on our current understanding of these processes. This will in turn shed light on a wide range of open questions in astrophysics and cosmology. In my work, I focus on the data analysis, where my colleagues and I process the data to enable comparisons with models, and on the theoretical calculations, where we consider what can be learned from each of these measurements.

One great thing about working in this field is how collaborative it is. The instruments, datasets, and theoretical models are too complex for any one person to be the world's top expert on all of it, so teamwork is a big part of what we do. Fortunately, the SO collaboration has experts in all the aspects of the experiment!

At CITA, our expertise is on theoretical modelling of the signals we expect to see, including working with large computer simulations, and on state-of-the-art analysis techniques for the data. It is exciting to be able to understand the process of the formation of structure from the big bang all the way to today!

Joy Didier

I always thought I was going to be a writer growing up, so pretty far from being an astrophysicist! That changed when I was 14 years old and my Physics professor started telling us about black holes. I started reading about them and was mesmerized that such insane objects were real and part of our universe. I read all the science popularization books, like "A Brief History of Time" by Stephen Hawking, and became more and more hooked with Physics and understanding the universe. Realizing that we were just a small planet and star system out of trillions, that looking in the sky was looking in the past, that the universe was evolving and was made mostly of stuff we didn't understand.... all those questions were really exciting, and the idea that your every day job could be about understanding the universe, too good to be true! After going to college in France with a major in engineering, I looked for a cosmology lab in the USA and did a one year internship in Amber Miller's lab at Columbia University. I had been pulled to cosmology because of all the exciting questions that come with the subject, but I stayed because working in a hardware lab was so much fun. That first year as an intern was when the balloon-borne EBEX CMB polarimeter had its test flight. Building the instrument, debugging what didn't work, calibrating all the sensors, writing the flight software, and finally seing the balloon take off in Fort Sumner, NM convinced me that this is what I wanted to do.

I started my PhD at Columbia University in 2009 and continued working on developing EBEX for its science flight. It was really exciting to spend four months in McMurdo, Antarctica to fly the EBEX experiment. The sun would never set at this season! The telescope flew with a helium balloon around the continent, and from 2013 to 2016 I led the data analysis to transform the raw data collected into sky maps of polarized light.

I earned my PhD in 2016 and since then I have been a Research Associate at the University of Southern California where a new experimental cosmology group is being developed. I joined the Simons Observatory (SO) and have been contributing to the study of the systematic errors in SO, particularly related to its Half Wave Plate. I have also been involved in developing the software pipeline that will be used to analyse the massive amount of data SO will collect.

Outside of work, I enjoy spending time with friends, cooking, and taking in the beautiful California nature through hiking and swimming.

Sara Simon

I began working in cosmic microwave background (CMB) cosmology in Nils Halverson’s lab as an undergraduate at the University of Colorado. I had previously worked on solar satellite telemetry code at the Laboratory for Atmospheric and Space Physics, but I was drawn to the big questions that cosmology posed: What is the universe composed of? Where did we come from? What will happen to the universe in the future? What can we learn about the physics of our universe from the CMB? In the two and a half years that I worked for Nils, I developed hardware and analysis code for detector testing and characterization. The two and a half years I worked there only made me more curious and passionate about the subject. I owe a lot to everyone who worked in the lab at that time because they were all really amazing mentors.

I decided to continue research in the CMB at Princeton University, where I worked on several experiments through my NASA Space Technology Research Fellowship, including the Atacama B-mode Search (ABS), ACTPol, and Advanced ACTPol (AdvACT). ABS deployed just as I was beginning my degree, so I spent a lot of time in Chile operating and characterizing the telescope and detectors. ABS was really exciting because it was a pathfinder experiment testing out novel instrumental technologies, which also left room to develop new analysis and characterization techniques. Princeton is the heart of the array assembly and integration for ACTPol and AdvACT. While it wasn’t my primary focus, I helped with array assembly when it was crunch time. I continued to be interested in novel technologies and designed new feedhorns (which couple light onto our detectors) for AdvACT.

I earned my Ph.D. in 2016, and I am currently a postdoctoral fellow at the University of Michigan. I’ve continued my work on AdvACT by designing the feedhorns and detectors for the low-frequency (27/39 GHz) array, and I am also a member of TolTEC, a high-resolution microwave camera for the Large Millimeter Telescope (LMT) in Mexico. I’m interested in combining these data sets with optical data sets to better understand galaxy clusters, which are the largest gravitationally bound objects in the universe and could thus help us better understand dark energy and dark matter. As a member of SO, I am active in the detector group and a leader of the calibration, sensitivity, and systematics (CSS) group. The CSS group is responsible for determining the sensitivity and systematics of various telescope configurations to aid in instrument selection and scientific forecasts, making a plan for characterizing and calibrating the telescope to minimize systematics, and acting as the main interface between the science and design groups.

Equality in STEM fields is one of my core principles. As a graduate student, I was the leader of the graduate women in physics group, where I became very active in working toward equal access and opportunity for all in physics through mentorship, providing career development resources, and improving the climate in STEM fields. It is this experience and passion that have driven me to develop a mentorship program for SO with the mentorship committee, which I also lead. The mentorship program is open to all in SO and will offer one-on-one mentoring between junior and senior members of SO. We’ll begin accepting applications in June around the SO meeting, so keep your eyes peeled! Outside of work, I like to keep busy with lots of hobbies, including baking, cooking, gardening, and photography. Many people in our lab like cooking and/or baking, so there’s always something to eat whether it be caramel, croissants, or smoked pulled pork!

Darcy Barron

I first started working on cosmic microwave background measurements as a graduate student at UC San Diego. As an undergraduate, I had worked in several labs on various technical projects, and really enjoyed the day-to-day building, tinkering, and troubleshooting that comes with getting an experiment to work. I decided to join Professor Brian Keating’s experimental cosmology group building telescopes to measure the cosmic microwave background (CMB) because it shared much of the lab work I enjoyed, but also came with an appealing grand goal of measuring new properties of our universe. I helped commission our first telescope, POLARBEAR-1, and continued to help design and build the next series of telescopes as we expand and improve our experiment, adding two more telescopes as part of the Simons Array. When I first arrived in Chile, our site was just some shipping containers and a bare telescope structure. By the time I graduated, our site wasn’t much more than that, but we had completed our initial CMB observations and published exciting new results detecting the signal we had set out to measure, the B-mode gravitational lensing signal.

In 2015, I finished my Ph.D. at UC San Diego and moved to UC Berkeley to continue working on the POLARBEAR/Simons Array project. I received an NSF Astronomy and Astrophysics postdoctoral fellowship, which supports me to continue my research as well as expand my involvement in education and outreach. Through the Multiverse group at UC Berkeley’s Space Sciences Lab, I am leading an NSF-funded research experience for undergraduates (REU) program, aimed at first-generation college students and community college students. The program brings a group of students to the lab for the summer to complete a research project in support of one of the NASA missions or other projects at the lab. I get to teach the students important skills and tools for research they wouldn't have encountered in their classes, as well as follow each student’s project and learn about new topics myself.

For Simons Observatory, I have begun working on optimization: helping study how to build the best experiment we can, given our capabilities and budget. While my research background helps me to frame and understand the technical problems we are studying, the question of how to best spend our resources also interests me. As a student, as I became more involved in research and learned along the way about the sources of funding, I became more interested in science policy and how these funding decisions are made. Advancements in astronomy and particle physics can require large (and expensive!) collaborative hardware projects to progress the field. The community and funding agencies must coordinate not just at the largest scales for mega projects like James Webb Space Telescope, but with overall priorities. Writing papers describing the current state of our field and what we plan to do next is an important part of this process, and I really enjoy being a part of it.

Outside of lab, I enjoy spending as much time as I can in the mountains backpacking, hiking, and stargazing. As a graduate student, I volunteered for the local Mountain Rescue Association team. In addition to all the useful technical training I received, being part of such a large team, running like a well-oiled machine, was an amazing experience. I have always enjoyed leading backpacking trips with friends, but this took the organization and preparedness to a whole new level. You quickly learn that self-sufficiency isn’t enough to be prepared to accomplish difficult tasks, or to help others in need.

I also enjoy the traveling that do as part of my job and research. My favorite part is trying new foods, whether it’s new dishes at restaurants or exploring snacks at a local grocery store. I’ve probably eaten over a hundred kinds of chips in the past several years! Most recently, I had fried pasta chips from a 7-Eleven in Japan; they were delicious.

Simone Aiola

Many people ask me why I chose Cosmology over other “more concrete” fields, and my answer is always “wouldn’t you do something that keeps you awake at night (and lets you travel a lot)?!”. I have been working on the Cosmic Microwave Background since I was an undergraduate student in Rome (Italy), where I investigated different designs for future balloon-borne experiments aiming to detect the signature of the first instances of the universe (called Inflation). During my masters, I worked on two aspects of the proposed Large-Scale Polarization Explorer: optimizing the strategy for pointing our telescope and putting our raw data into maps of the sky (in this field we call this “map-making”). In 2012, I moved to the US and started my graduate studies at the University of Pittsburgh under the guidance of Prof. Arthur Kosowsky, with the desire of focusing on more theoretical aspects of cosmology. For a couple of years, I studied the statistics and anomalies of CMB photons that emanate from two points on the sky that are far apart (i.e. large angular scales). Following these studies, I got involved with the Atacama Cosmology Telescope collaboration and started working in three quite different areas ranging from analyzing the raw data to looking for cosmological signals (for the experts out there… map-making, time-domain analyses, as well as the detection of the kinetic Sunyaev-Zeldovich effect via pair-wise momentum). In September 2016, I became a postdoc at Princeton University, where I have the pleasure to keep analyzing the raw data coming from the ACTPol/AdvACT polarimeters, making high-quality CMB maps, and, more recently, looking at the gravitational-lensing effects of CMB photons coming from nearly the same point on the sky (i.e. small angular scales).

As a member of the SO collaboration, I am active in the time-domain working group. There is a lot that can be learnt from currently operating CMB experiments, and this group can offer insightful guidance towards realistic forecasting and an optimized telescope design.

Although my work keeps me awake at night, I do like to set the weekends away from my job. I am not much of a “nature” person; rather I enjoy the vibes of big, vivid, and active European and American cities –– Princeton is only one hour away from either Philadelphia or New York City! I like art, photography (although I am not great at producing breath-taking shots), and good food, especially if I make it. I used to practice a lot of classical and modern dance when I was young. Currently, I moved that need to jump up and down in the gym, just to make sure that “mens sana in corpore sano (healthy mind in a healthy body)”.