{"id":62878,"date":"2021-05-28T10:10:46","date_gmt":"2021-05-28T17:10:46","guid":{"rendered":"https:\/\/in.nau.edu\/news\/?p=62878"},"modified":"2021-06-01T11:37:10","modified_gmt":"2021-06-01T18:37:10","slug":"gialluca-grfp","status":"publish","type":"post","link":"https:\/\/in.nau.edu\/news\/gialluca-grfp\/","title":{"rendered":"Dark matter amid the dark skies: In four years at NAU, research takes grad to the ends of the universe"},"content":{"rendered":"

As a first-year student at NAU, Megan Gialluca<\/strong> walked into astronomy professor Ty Robinson\u2019s<\/strong> office, introduced herself and told him she was interested in doing research with him.<\/p>\n

Four years later, she\u2019s leaving NAU as a Goldwater Scholar and with three years of funding for a Ph.D. in hand as a recipient of the NSF\u2019s Graduate Research Fellowship Program (GRFP) award.<\/p>\n

Gialluca graduated in April with a degree in astronomy and has spent her NAU career focused on research and science education, including winning grants to run her own research projects, collaborating with a Harvard researcher to study dark matter and working at Lowell Observatory\u2014an opportunity that helped get the New Hampshire student to NAU four years ago.<\/p>\n

\u201cIt\u2019s been a long road,\u201d said Gialluca, whose next stop is the University of Washington for a Ph.D. in astronomy and astrobiology. \u201cIt\u2019s very much a sum of a lot of hard work and advising, which is why you should just ask. You will be surprised how many people will say yes to you.\u201d<\/p>\n

Gialluca\u2019s doing the kind of research that affects everyday life\u2014but most people don\u2019t know how or why it affects them. Her research with Robinson has been focused on looking for habitability indicators or biosignatures\u2014evidence that other planets could host life or had hosted life at some point in the past. It\u2019s a question that has fascinated many for decades.<\/p>\n

She\u2019s also interested in near-Earth objects and where these objects originate, she wants to get people as excited about the night sky as she is, and then there\u2019s still the matter of dark matter, which makes up most of the universe.<\/p>\n

\u201cI would like to know more about what makes up most of the universe,\u201d Gialluca said. \u201cDark matter is intimately tied to how the universe will eventually end. I think it would be nice to have an idea of where all this is headed.\u201d<\/p>\n

Transit spectroscopy research<\/strong><\/h3>\n

Transit spectroscopy is the science of gathering data from the passage of a celestial object as it passes in front of a star. As an object moves in front of a star, light from that star passes through the planet\u2019s atmosphere which can be used to determine what gases are present there. Knowing what gases exist on a planet is a critical component to tracing biosignatures, or the possibility of some form of life on that planet.<\/p>\n

But her research isn\u2019t just looking at what\u2019s there. It\u2019s looking at what a researcher would expect to see when looking through the lens of the James Webb Space Telescope (JWST)\u2014 planned to succeed the\u00a0Hubble Space Telescope<\/a>\u00a0as NASA’s flagship\u00a0astrophysics<\/a>\u00a0mission sometime this year. Gialluca collected enough data to write a Python program to create a model. She tells the program what\u2019s in the atmosphere, and then it tells her how the data she provided, which is ideal and very detailed, would look through the lens of the JWST\u2014it degrades \u201cperfect\u201d data to what JWST would see, including uncertainties such as light from the sun, broken pixels on the telescope and other potential points of distraction. It will help researchers figure out where to point the JWST to make better use of their telescope time.<\/p>\n

This data is critical because right now, all astronomers throughout the world will use the JWST to track any number of objects, including exoplanets, so time on the telescope is \u201csuper, super, super valuable and really hard to get,\u201d and researchers want to be able to say exactly where they\u2019re looking and what they expect to find. Current models show what the exoplanet atmospheres should look like; Gialluca\u2019s model helps researchers predict what they will see with all the noise.<\/p>\n

Given the vastness of space and the sheer number of variables researchers have to consider, adding a little predictability can go a long way.<\/p>\n

\"Megan<\/a>
Megan Gialluca, spring 2021. Top photo:\u00a0Gialluca at an occultation event for the Lucy mission with Lowell Observatory\u00a0<\/em><\/figcaption><\/figure>\n

\u201cIn this scenario, I have a model that already tells me what\u2019s in the atmosphere, and the code returns to me what the JWST would see and what the atmosphere would look like to astronomers,\u201d she said. \u201cMy code degrades the data to what the JWST would realistically observe. My work is going to be super useful for people who want to observe transits of planets with JWST and will help researchers argue that it\u2019s worthwhile for them to get JWST time to observe a system because they\u2019ll be able to see it in these conditions.\u201d<\/p>\n

The years of work on this project paid off in Gialluca\u2019s final months at NAU; in March, it was accepted for publication in Astronomical Society of the Pacific.<\/p>\n

The enigma of dark matter<\/strong><\/h3>\n

The summer before her senior year, Gialluca did an NSF-funded Research Experience for Undergraduates (REU) program \u201cat\u201d the Harvard Center for Astrophysics, though the pandemic kept her in Flagstaff. She worked with Ana Bonaca, a postdoctoral scholar at Harvard, to study dark matter, the mysterious substance that makes up most of the universe but about which scientists have vanishingly little knowledge, and stellar streams, which are long, thin streams of stars that are created when satellites of the Milky Way like globular clusters are tidally disrupted (pulled apart by the galaxy\u2019s gravity).<\/p>\n

Bonaca was originally looking at structures called stellar streams, which are created when a globular cluster (a big cluster of stars or a dwarf galaxy) is disrupted by title forces. This means that gravity acts more on parts of the stream that are closer to the sun, which pulls harder on some parts of the cluster than others and shifts the cluster into a long, thin stream. These streams also are quite sensitive to galactic forces, including mass, gravitational potential and dark matter.<\/p>\n

With that last variable, the mystery deepens.<\/p>\n

\u201cThere are big questions with dark matter\u2014does it exist in clumps in the galaxy?\u201d Gialluca said. \u201cHow much is the mass of a dark matter particle? And can we use stellar stream observations to inform us on what a mass of single dark matter particles would be?\u201d<\/p>\n

Combining what they know about dark matter\u2014very little\u2014with what they know about stellar streams, Bonaca and Gialluca looked at the velocity of stars in the stellar stream and how much they deviated from their orbit. This velocity dispersion (the movement along the Y axis as the star moved on the X axis) is affected by the mass of the Milky Way and other factors that come into contact with the stream\u2014factors like dark matter particles, which are hypothesized by some to exist in clumps scientists refer to as dark matter sub-halos. If these particles exacerbate the star\u2019s velocity, that could help them estimate the mass of a dark matter particle.<\/p>\n

Using Python modeling, they came up with an estimate for that mass. That estimate was three magnitudes below the lower limit of what that mass could be, so obviously, Gialluca said, their estimation was incorrect.<\/p>\n

\u201cBut in science, even when you fail, that\u2019s usually an opportunity to learn something new,\u201d she said. \u201cInstead of estimating mass, our overarching goal was to present a well-constrained velocity dispersion measure of this stream (the GD-1 stream) and provide evidence that the stream has been perturbed by an outside object.\u201d<\/p>\n

Their research showed that something had affected those streams, which meant particles were interacting with the stars.<\/p>\n

\u201cIf you account for all of the possible heating sources in the stream and the velocity disruption is still too small, it either means the dark matter model isn\u2019t working or there are other things that have caused the velocity to get larger that we haven\u2019t considered,\u201d she said. \u201cThere\u2019s something else going on in the stream and we don\u2019t know what it is.\u201d<\/p>\n

Science outreach at Lowell Observatory<\/strong><\/h3>\n

Gialluca also has astronomy work that is a little closer to home\u2014literally. Like many NAU astronomy students, she worked at Lowell Observatory while she was here. She started as a public program educator, offering tours and running telescope programs in the evening. Halfway through her junior year, she was promoted to research assistant, helping astronomer Nick Moskovitz on a five-year NSF-funded project, LOCAMS, with the goal of capturing every meteor that shoots through the Arizona sky.<\/p>\n

\u201cThe end goal of this is to have complete coverage of Arizona and parts of New Mexico,\u201d she said. \u201cAnytime anyone is outside camping and they look up and see a super cool meteor go across the sky, we\u2019ve observed it. At least one camera has seen that and recorded it for us.\u201d<\/p>\n

It’s big data at work, she said. With low-cost security camera systems installed at sites throughout the state, including Sedona, Prescott, Window Rock, Happy Jack, Flagstaff and others, they should be able to capture everything out there, which can range from a couple hundred to 500 or 600 meteors a night during a meteor shower. Besides simply capturing them in the sky, the camera systems should allow the researchers to determine if meteors dropped any rocks or where they are likely to be, so they can retrieve the rocks quickly.<\/p>\n

\u201cIf we can go get them within a couple of days, we know it\u2019s fresh, it just came from space and it hasn\u2019t been subjected to Earth\u2019s process that might make it less useful,\u201d she said. \u201cOur dream would be a giant meteor coming in that we observed, we see that it dropped rocks, we\u2019re able to retrieve the rocks and we\u2019re able to look at the orbit and identify the parent body of the meteor.\u201d<\/p>\n

\"Megan<\/a>
Gialluca presents at the Undergraduate Research Symposium in 2019.<\/em><\/figcaption><\/figure>\n

In addition to setting the cameras up, Gialluca is helping to create and populate the database where all of this information is living. They want that database to constantly update so someone who sees a meteor one night can check it the next day and learn more about it. That remains an ongoing process, she said.<\/p>\n

Her work at Lowell played a significant role in her GRFP application; the NSF looks for educational outreach efforts among applicants, as bringing science to non-scientists in an interesting, informative way is an important part of the organization\u2019s mission. It\u2019s important to Gialluca too, as the science she\u2019s participating in affects society in so many ways that people often don\u2019t consider. Knowing the history of habitability on Mars or Venus, for example, could be an indicator of Earth\u2019s future or its past. The happenings in the galaxy aren\u2019t quite as far, far away as people believe and have greater effects on Earth than most of us understand. And dark matter, though it\u2019s an enigma, is, quite literally, everywhere.<\/p>\n

Applying for the GRFP<\/strong><\/h3>\n

Undergraduate students are allowed to apply twice: once as a senior moving into graduate school and once as a graduate student. Gialluca went into the process expecting it to be a good practice run for next time.<\/p>\n

Instead, she woke up one day in March to find her phone buzzing with emails, including one from Robinson telling her she had some mail from the NSF. She hadn\u2019t even decided where she was getting her Ph.D. when she found out she received the funding.<\/p>\n

The GRFP is a research grant, but research is not the only factor the NSF considers. The application asks about outreach and science education and asks scholars to talk about their own life stories. Gialluca talked about her life goals, her interests, the broader impact she wanted her work to have and her college career\u2014and, of course, her research, leading with the day she walked into Robinson\u2019s office, introducing herself and asking to work with him in one breath.<\/p>\n

\u201cExtremely few freshmen possess the self-confidence and personal vision required to solicit research opportunities shortly after arriving on campus,\u201d Robinson wrote in his letter to the NSF recommending Gialluca. \u201cMegan arrived with a copy of an independent research study report from high school and ready to answer questions, and she was able to clearly state plans for her research in my group.\u201d<\/p>\n

Gialluca\u2019s initiative continued to impress Robinson; she jumped into learning Python coding, applied for funding, first from NAU and then NASA to lead her own projects, then earned a Goldwater Scholarship as a sophomore. He saw the same drive and organization as she worked through her research projects, which played a significant role in getting publishable results.<\/p>\n

\u201cMegan is clearly on the path to research greatness,\u201d he said. \u201cFew times in our lives do we meet young people where we think, \u2018this person is really headed somewhere!\u2019 That was my initial reaction to meeting Megan, and I am now even more certain of this assessment.\u201d<\/p>\n

\n

Editor\u2019s note: Six NAU students were selected for the National Science Foundation\u2019s Graduate Research Fellowship Program. Read about their research.<\/em><\/h3>\n

Jessica Archibald:<\/strong> Managing mangroves: GRFP recipient Jessica Archibald studies social-ecological approaches to forest restoration<\/a><\/p>\n

Jonathan Chin:<\/strong> Building a better solar panel: NAU graduate wins NSF award to continue research into sustainable energy<\/a><\/p>\n

Ethan Taber:<\/strong> Two years after Museum Fire, NAU grad student looks at what slow regeneration of fire site could mean for the future<\/a><\/p>\n

\"Northern<\/a><\/p>\n

 <\/p>\n

Heidi Toth | NAU Communications
\n(928) 523-8737 | heidi.toth@nau.edu<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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