Author: Victoria Kabakian

CFPU

Brown researchers to help build telescope to study exoplanet atmospheres

Victoria Kabakian |

With a new grant from NASA, Brown physicist Gregory Tucker and a team of students will help to build a telescope that can study the atmospheres of distant planets.

PROVIDENCE, R.I. [Brown University] — A Brown University professor and his students will play key roles in building and operating a new telescope designed to unlock the secrets of planets orbiting distant stars.

Gregory Tucker, a professor of physics, received a $2.5 million grant from NASA to build components for the Exoplanet Climate Infrared TElescope (EXCITE). The instrument, which is designed to fly suspended from a high-altitude balloon, combines a powerful telescope with a spectrometer capable of probing the atmospheric characteristics of exoplanets. In particular, EXCITE will study hot Jupiters, planets that are about the size of the largest denizen of the Earth’s solar system but orbit surprisingly close to their host stars.

“When people were first searching for exoplanets, nobody expected hot Jupiters to exist because it’s not clear how they would form,” Tucker said. “But they turn out to be quite common, and because of their size we can measure the properties of their atmospheres and get an understanding of their atmospheric dynamics.”

The EXCITE instrument is designed specifically to do just that. The project is led by Peter Nagler, a researcher at NASA’s Goddard Space Flight Center who helped to develop the idea for the instrument while a Ph.D. student at Brown working with Tucker.

EXCITE is designed specifically to probe atmospheric dynamics.

Tucker says that EXCITE will have some distinct advantages over space telescopes and other large-scale instruments when it comes to studying atmospheres. Observation time on space telescopes is precious, meaning they generally take relatively quick looks at lots of different targets. EXCITE, on the other hand, will be able to stare at individual planets for days at a time as they orbit their host stars.

Hot Jupiters have short orbital periods of less than 10 days, which means EXCITE can gather continuous data from a planet throughout its orbital cycle. That can provide detailed information about the composition of an atmosphere as well as to track key dynamics driven by temperature and pressure.

For example, Tucker says that EXCITE could potentially determine wind speeds on a planet by studying its substellar point — the spot closest to a host star.

“You’d expect this closest point to be the hottest spot on the planet because it’s constantly heated by the star, but in fact we tend to see a small eastward shift,” Tucker said. “That’s because the atmosphere is redistributing that heat, and we can use that shift to determine wind speed.”

To get these kinds of observations, EXCITE will fly 25 miles up in the skies above Antarctica. That altitude removes interference from much of the Earth’s atmosphere, which over Antarctica is already clear, dry and optimal for telescope viewing. To reach that altitude, the SUV-sized EXCITE instrument will be tethered to a balloon about the size of a football stadium when fully inflated.

Among the components to be developed at Brown is a cryogenic system for the instrument’s spectrometer. Interference generated by the optics inside the spectrometer itself could obscure the signals that the researchers are trying to detect. By cooling the optics down, the team can minimize that interference.

“We’re basically putting it in a big Thermos bottle with a mechanical cooler,” Tucker said.

Tucker’s team will also help with integration and assembly of the full instrument. When EXCITE is ready to fly, Tucker and his students will provide flight support and aid in data analysis. The team hopes to start building components next year and begin flights sometime in the next few years.

Ultimately, Tucker hopes that EXCITE will provide data on exoplanet atmospheres that other instruments can’t capture — information that could help scientists better understand how solar systems form and evolve. And the technical insights provided by EXCITE could push the study of exoplanet atmospheres forward even further.

“Eventually we’d like to be able to study the atmospheres of smaller Earth-size exoplanets, but the technology isn’t quite there yet,” Tucker said. “I think this could be a good path to getting toward the study of these more Earth-size planets.”

Original article: https://www.brown.edu/news/2020-10-01/excite

CFPU

2020 Research Seed Award Recipients

Victoria Kabakian |

Congratulations to Prof. Gregory Tucker.

Cosmic History from Mapping the Universe with Neutral Hydrogen
Measuring the intensity of 21 cm emission from neutral hydrogen gas is a novel technique that enables mapping large volumes of the universe in three dimensions.  The Tianlai Pathfinder has been carrying out a North Celestial Cap Survey (NCCS). The Tianlai Pathfinder is unique among 21 cm instruments in being able to point and integrate continuously on a limited patch of sky for extended periods.  With seed funding Brown could contribute to analyzing this rich data set and produce initial results which will strengthen subsequent proposals. One of the ultimate goals of this research is to measure baryon acoustic oscillations over cosmic time to help understand dark energy, which is currently not understood.  This research will also, for example, shed light on the mysterious fast radio bursts (FRBs), detect radio counterparts of gravitational events from sources such as merging neutron stars and lead to a better understanding of galaxy formation. The Tianlai Pathfinder will demonstrate the feasibility of using wide field of view radio interferometers to map the density of neutral hydrogen in the universe after the Epoch of Reionization (EoR).  Such radio interferometers are relatively new, and the necessary techniques are still being developed. The Tianlai Pathfinder is also unique in that it consists of two co-located interferometers utilizing different types of antennae (cylinders and dishes), which provides an important opportunity to compare the ultimate performance of these two types of telescopes as the next generation of more sensitive instruments is planned.
PI: Gregory Tucker, Professor of Physics
Funded: $44,000

Original article: https://www.brown.edu/academics/physics/news/2020/02/2020-research-seed-award-recipients

CFPU

National Society of Black Physicists conference comes to Providence

Victoria Kabakian |

Stephon Alexander, Brown professor and president-elect of the National Society for Black Physicists, discusses the organization’s annual conference, which comes to Providence for the first time this year.

For more than 40 years, the National Society of Black Physicists (NSBP) has provided support and mentorship to African American and black scientists seeking physics careers both in academia and industry. This week, the organization brings its annual conference to Providence for the first time.

The conference, sponsored in part by Brown University, is the largest academic meeting of physicists from historically underrepresented groups in the United States, the organization says. The roughly 400 attendees are a mix of students and professionals from around the country and beyond, coming together for mentorship, networking opportunities and to generate new research collaborations.

For Stephon Alexander, professor of physics at Brown, having the conference in the city where he lives and works is particularly special. Alexander joined NSBP as a young undergraduate and aspiring physicist. Now he’s a member of the Brown faculty and president-elect of NSBP. He’s says it’s gratifying to be part of two organizations with the shared goal of making education and research more inclusive endeavors.

Alexander discussed this year’s conference, which takes place from Nov. 14 to 17 at the Marriot Downtown Hotel, in an interview.

Q: Can you share an overview on NSBP and its mission?

The goal of the NSBP is to promote the professional well-being and success of African American and black physicists, with an emphasis on fostering excellence and innovation. I think the organization is a good example of how a group of people who, for the love of their field, decided to come together at a time when they were explicitly not welcome in some places. Instead of giving in or giving up, they built this community around their passion and desire to do research and to teach.

Q: What’s the aim of this week’s conference?

The conference is a gathering of students and professionals from industry and academia — a very broad and varied group of physicists. The theme of this year’s conference is “Promoting Professional Connections and Persistence in Physics,” so there will be a lot of networking opportunities and chances for people to learn what their fellow physicists from around the country are working on. For the most part, it’s people getting together to talk about their work and their love for physics and science. Hopefully that results in new collaborations and new friendships.

Q: Can you describe your experiences at past conferences?

I’ve been an NSBP member since my freshman year of college, and this conference is where I met many of my mentors, including Jim Gates [a Brown professor and National Medal of Science winner], who will give a keynote talk this year. As an undergraduate, I had a bit of a low opinion of myself in terms of my abilities, and this conference gave me confidence. I remember a moment from one of my first conferences during a lunch break. There was a table of very distinguished black physicists — people from MIT and Duke — and they just called me over to the table like I was their nephew. It was like, ‘come join us here,’ and it gave me a sense of belonging and that I was being taken seriously. Now 20 or 30 years later, these people are my colleagues. Being the incoming president, if I can contribute to enhancing that type of culture, that would be great.

Q: What are some of the highlights on the schedule?

The leaders of each of our scientific program areas — like astrophysics, condensed matter, quantum mechanics and others — will host programming specific to each of those areas. We’ll also have plenary sessions and keynotes for the whole group. I’ll be giving a talk. We’ll also have James Simons, the mathematician and founder of the Simons Foundation. Jami Valentine Miller, the first African American woman to get a Ph.D. from Johns Hopkins, will speak. Jim Gates will give a keynote, as I mentioned, as will Brian Keating, who led the BICEP cosmic microwave background experiments.

Q: As NSBP president elect, what does it mean to you to bring this conference to Providence?

This conference, and NSBP’s mission in general, are very much in line with Brown’s commitment to inclusivity and excellence in the sciences. Our leadership group at NSBP realizes that about Brown, and I think that played a big role in the calculus to bring this to Providence. So as a member of both organizations, that’s very gratifying. The office of Provost Richard Locke has been great about providing sponsorship for the conference, and we’re very appreciative of that support.

Photo credit: Nick Dentamaro

Original article: https://www.brown.edu/academics/physics/news/2019/11/national-society-black-physicists-conference-comes-providence

CFPU

Announcing the new Center for the Fundamental Physics of the Universe (CFPU)

Victoria Kabakian |

The new Center for the Fundamental Physics of the Universe (CFPU) at Brown brings together researchers engaged in experimental and theoretical work aimed at answering some of the major fundamental questions about the physics of the Universe.

The roster includes faculty from various sub-disciplines: four from Astrophysics and Cosmology Experimental work (Dell’Antonio, Gaitskell, Pober, Tucker), three pursuing Astrophysics and Cosmology Theory and Phenomenology (Alexander,  Fan, Koushiappas) and four High Energy Experimentalists (Cutts, Heintz, Landsberg). We are also working in conjunction with Faculty from Condensed Matter research and also Planetary Sciences.

We have a strong group of theorists working on problems relevant to astroparticle cosmology. As illustrated in the figure the theoretical work spans new models from the very earliest  times addressing the inflationary phase at the start of the universe, through models of dark matter and dark energy controlling the evolution of the universe as important features at multiple distance scales are forming, to models addressing the potential production of dark matter at present-day particle accelerators. One of our major goals is to identify and develop new cross-disciplinary techniques for future experimental searches to better understand the dark matter and dark energy. We are encouraging full exploitation of the breadth and depth of the expertise at Brown to develop new experimental techniques, as well as new interpretations of the implications of current experimental data.

The CFPU will also significantly aid recruitment of junior researchers by further raising the profile of our very successful Particle, Astrophysics and Cosmological research programs for the potential new graduate students and postdocs. We must ensure that young researchers share the excitement of the Center’s wide range of interconnected physics activities – attracting the very best researchers is critical to our efforts. The CFPU is providing funding to kick-start new research ideas spanning multiple faculty. The CFPU can also fulfill an important role by acting to coordinate future applications for large-scale funding in block grants/science centers programs.

In our initial start-up we have already been able to provide support for conferences and meetings covering dark matter direct detection (IDM2018), particle detector instrumentation development (CPAD2018) and the Murchison Widefield Array 21-cm signal experiment. We have also supported a new dark matter search proposal in Axion physics that exploits quantum-sensitive NMR techniques developed in the condensed matter research (Mitrovic) at the department. We identified and obtained funding from DOE to exploit deep neural network/machine learning to analyze research results coming from groups in dark matter lensing, dark matter direct detection and high energy accelerator particle searches. The Center is also sponsoring machine learning workshops for undergraduates and researchers at the department to ensure that a wide appreciation of what the new techniques can be used for most effectively.

We will continue to explore new potential synergies between our areas of experimental research. Our research groups are developing and fabricating new detector technologies in related areas of advance photodetectors, low noise detectors, fast electronics and data acquisition systems. We face the challenge of handling large >PB data sets and use similar analysis techniques, so we are developing a plan to best support these efforts. The CFPU is already playing a critical role at the Physics department and we are very optimistic about exploiting future research opportunities that can be carried out at Brown with new resources.

Original article: https://www.brown.edu/academics/physics/news/2019/09/announcing-new-center-fundamental-physics-universe-cfpu