Advancing Humanity’s Knowledge About Merging Galaxies and Their Blackholes

Derek Hand and Andreea Petric in their office at the Institute for Astronomy, UH Hilo University Park of Science and Technology.

Derek Hand and Andreea Petric at the Institute for Astronomy, University Park of Science and Technology, UH Hilo campus. Click to enlarge.

A budding scientist double majoring in physics and astronomy at the University of Hawai‘i at Hilo has helped make an astonishing discovery about merging galaxies.

After receiving a bachelor of science in astronomy last fall, UH Hilo senior Derek Hand is now finishing up his second baccalaureate degree, this one in physics. He is a NASA Space Grant Fellow who joined forces with astronomer Andreea Petric when she was a science fellow at Gemini Observatories. She now serves as resident astronomer with the Canada-France-Hawai‘i-Telescope.

Together, student and mentor have been working to analyze data that will advance humanity’s knowledge about merging galaxies and the growth of the central black holes they encompass.

While conducting analysis of their observations, Petric and Hand made a surprising discovery that, once verified, will be a new contribution to science.

They found that Active Galactic Nuclei (AGN), or as Petric describes, “super massive black holes that are eating,” can have a dramatic impact on the matter from which galaxies make their stars. This is surprising because the transfer of energy ranges from the very small physical scale to the very vast galaxy-wide scale.

Derek Hand working on his research project.

Derek Hand working on his research project. Courtesy photo.

The project is an independent research process. Hand came up with the research proposal and does the research while Petric provides guidance. Hand gives this scientific description of the work:

Our CO data comes from the Herschel satellite in the far Infrared (~200 -700) microns. We will be observing transitions of the 12 CO carbon monoxide (CO molecule). The CO molecule has rotational kinetic energy, proportional to its angular momentum. Quantum mechanics tell us tells us that the angular momentum and hence the rotational energy are quantized such that the rotational energy is proportional to angular quantum number J as J (J+1), with higher J at higher energy levels.

So the upper-level energies Eu for CO transitions are proportional to J(J+1). The corresponding minimum temperatures for J upper = 13 are on the order of a few hundred K and so high – J lines are weak in cold molecular gas but strong in regions of star-formation or when there is AGN heating the gas.

So for this project with Herschel we observed warm CO, transitions J=4-3 to 13-12, to compare see if and how the CO excitation conditions change in LIRGs as a function of merger stage and AGN contribution to the IR.

In addition I performed a long and tedious literature search to obtain all the CO 1-0 measurements, as this probes the coldest CO an the one that is most closely associated with star-formation. I found measurements for (168??) but there is a small hitch. These observations were performed with single dish observatories and results in these objects being observed differently while the SPIRE/FTS beam size varies between 20 and 40′′, and to correct for this, we must scale this data. To do so, we will employ Herschel Far Infrared observations to estimate the CO(1-0) that may be present in the Herschel aperture (that is, go from a 1-2 arcminute scale to about a 30 arcsecond scale).

Collaboration

The mentorship of Petric has been invaluable to Hand’s start as a serious scientist. Petric, a member of the physics and astronomy faculty at UH Hilo, received her doctor of philosophy from Columbia University and was a postdoctoral fellow at California Institute of Technology, where she worked on infrared and millimeter observations of interacting galaxies and galaxies hosting Active Galactic Nuclei (AGN).

In order to make their recent discovery about AGN, Petric and Hand collaborated with scientists from the University of Virginia, the Caltech Submillimeter Observatory, the Institute for Astronomy at UH Mānoa, and groups in France and Japan. Working together, they used multiple data sets to study the properties of the molecular gas in Luminous Infrared Galaxies.

Petric and Hand are currently using different methods and data from other sources and telescopes to verify the discovery. Once that is done, they have a plan in-the-works to write and publish a paper on their findings.

Applied learning

All of this may not have been possible without the opportunities provided at UH Hilo where students can apply their knowledge gained in the classroom to real life experience.

Petric and Hand met through the Akamai Internship Program. The six-week program offers college and university students an opportunity to gain a summer work experience at an observatory, company or scientific or technical facility in Hawai‘i. Akamai offers training, skill acquisition and first-hand experience working alongside mentors, managers, and fellow interns. Promising college and university students who excel in their chosen industries are given a jump start into their careers.

After Petric and Hand were matched through the Akamai program, they found shared interests and formulated the research idea that would eventually lead them to new discoveries about the role of interacting galaxies on star formations and black hole growth.

This led Hand to pursue a highly competitive Space Grant from NASA. Funding was awarded and the rest may, quite possibly, go down in history.

Becoming an astronomer at UH Hilo

Derek standing in front of observatory dome

Derek Hand on the summit of Maunakea. Courtesy photo.

Hand, who hails from Bemidji, Minnesota, and graduated from Mount Ayr Community High School, Iowa, in 2012, says, “I came to Hawai‘i because the (UH Hilo) astronomy and physics department does have its own observatory.”

The observatory is currently closed for maintenance, but is scheduled to be up-and-running in about eight months. In the meantime, Hand felt he had enough class work and experience to apply for an internship.

“I wanted to work with real data, with real people, working on real research, that’s where I learn the best,” he says.

Hand feels that it helps to apply the tools acquired in the classroom and believes that the application emphasizes their importance.

He says that one of the most valuable lessons he has learned, thanks to his internship and subsequent NASA fellowship working with Petric, has been the independent research process. In the past people had told him what to do, but Hand is grateful for Petric’s approach.

“Andreea more-or-less says ‘this is what needs to happen, you should figure out how to do it,’” explains Hand.

Petric says the long time period of the grant played a large role in the work.

“We had a long time, that’s why I think the Space Grant is a wonderful opportunity,” she says. “A lot of UH students have classes and they also have jobs. On top of that they want to be involved in research, but it’s quite difficult, there isn’t enough time. That’s why the Space Grant is great, it provides extra funding and time.”

Petric also points out other benefits, such as skill development through specific literature searches, computing faculties and technical language acquirement.

The team will continue their research this semester, looking at other founts that will help them understand whether their discovery is in fact confirmable. They plan to write and publish a paper discussing their findings, should they be successful.

Hand will be graduating this May, completing his double major in astronomy and physics. He has applied to graduate school.

The Chemistry of the Universe

UH Hilo undergraduate Jasmin Silva started her journey into astronomy research when she received a NASA Hawai‘i Space Grant Consortium fellowship in 2015.

Jasmin at computer, fronting several screens with data on desk and wall.

Jasmin Silva

Jasmin Silva, a junior at the University of Hawai‘i at Hilo, is working alongside mentor Kathy Cooksey, an assistant professor of physics and astronomy, conducting research contributing to the understanding of the gaseous structures surrounding galaxies and how they evolve over time. It is a way of understanding the chemistry of the universe and what has been created by stars.

Silva, a double major in physics and astronomy with a minor in mathematics, started her journey into research and discovery when she received a NASA Hawai‘i Space Grant Consortium fellowship for the spring and fall 2015 semesters. This fellowship allows undergraduate students enrolled in fields relevant to NASA’s goals to do research alongside a mentor who is typically a faculty member.

Silva has been working on her project, “Understanding Galactic Evolution through Absorption,” under the guidance of Cooksey, a highly accomplished astronomer who arrived at UH Hilo in 2014. Cooksey researches the large-scale gaseous structure in the universe to understand how various elements cycle in and out of galaxies over cosmic time. Her specific area of expertise is the intergalactic medium (IGM), the gas surrounding and between galaxies.

From Waiakea High School to astronomy research

Silva is using data from the Sloan Digital Sky Survey to construct and analyze quasar absorption-line spectra of the cosmos. Some of this work is done remotely at the UH Hilo campus. Silva was also able to observe with the 10-m Keck II Telescope, which is located on Maunakea but data collection is done remotely at the headquarters in Waimea.

The initial interest in the fellowship was sparked by a classroom encounter. Silva was enrolled in one of Cooksey’s classes already having taken physics at Waiakea High School, and this proved helpful.

Cooksey notes, “She was more advanced at some levels and focused on getting her astronomy degree.”

Silva says, “Kathy asked me to do research with her, but before that it was definitely in my head that sometime in my career I would do research. If you want to go to graduate school a lot of it is research. I figured I would want to get that kind of experience, then Kathy gave me a good opportunity.”

It was the first applied learning experience for Silva as a student.

The boost of applied learning

Something that Silva really appreciated about the fellowship was the fact that undergraduates were able to have the experience of writing their own research proposal and organizing a time scale in which to carry it out.

She explains, “It’s important for the future, when you are applying for grants or fellowships, to know how to do that.”

Silva also feels that the applied learning experience encourages students and allows them to see what they are capable of— “It helps me be more confident that I can do graduate school in the future.”

Cooksey herself conducted many research projects as an undergraduate and feels that the experience gained in applied learning is necessary for those wishing to continue on to graduate school.

She says, “Computer skills, thought processes… grad school wants you to hit the ground running. It’s great that the UH System is a Space Grant Institution that is allowed to get this NASA (funding) to pay for interns to get them started. Jasmin is now in a better position to get into more prestigious programs.”

Silva just finished her final semester of research with the fellowship but has continued to work independently with Cooksey. She is also applying to other internship opportunities and grants, including a summer internship with Gemini Observatories.

She feels that her undergraduate education has been supplemented by the fellowship. Silva believes that the experience has helped prepare her to educate the public about the science community (she serves as an astronomy educator in the Hilo-Waiākea Complex Area) and she encourages other university students to apply for similar opportunities.

She plans to continue on to graduate school.

Originally published at UH Hilo Stories