APS Membership Unit Profile: The Division of Astrophysics

By Abigail Dove

With almost 3,000 members, the Division of Astrophysics (DAP) is a home for physicists striving to understand the universe and our place in it through the study of planets, stars, nebulae, galaxies, and other aspects of the cosmos.

DAP was founded in 1970 as a niche for researchers principally concerned with the physics underlying phenomena in space, rather than their observational study—the major focus of astronomy at the time. Now, over 50 years later, astrophysics has matured into an incredibly broad field, encompassing everything from galactic structure and evolution to the early history of the universe to the physical processes occurring in stars.

At the end of 2021, the most pressing research questions in astrophysics were outlined in the Decadal Assessment, a project coordinated every 10 years by the National Academy of Sciences with the aim of educating federal agencies and policymakers about the most important research topics and funding priorities in the field. These include (1) understanding stars and the planets that orbit them, specifically to identify worlds resembling Earth that may have signatures of life; (2) multi-messenger astrophysics, the use of complementary information from four different sources, or “messengers”—electromagnetic radiation, gravitational waves, neutrinos, and cosmic rays—to understand the cosmos; and (3) better understanding so-called “cosmic ecosystems,” particularly the driving forces behind star formation and the growth of galaxies.

“The fun thing about astronomy is that it ties together so many physics fields,” explained DAP chair Chris Fryer (Los Alamos National Laboratory). Indeed, given the major emphasis on early universe cosmology and phenomena like black holes and gravitational waves in the astrophysics community, DAP has fostered very close collaborations with several other APS divisions—most notably the Divisions of Nuclear Physics (see APS News January 2021), Particles and Fields (see APS News April 2021), and Gravitational Physics (see APS News October 2021). DAP also has considerable synergy with the Division of Fluid Dynamics (see APS News July/August 2020) when it comes to the study of nebulae in interstellar space, the Division of Plasma Physics (see APS News October 2020) given the abundance of plasmas in planetary cores and stars, and the Division of Atomic, Molecular, and Optical Physics (see APS News April 2020) as it relates to interpreting the light emitted from objects in space and the molecular basis of star and planet formation from giant molecular clouds.

With such strong interdisciplinary ties across many different areas of physics, a major highlight of DAP’s activities is the APS April Meeting, where the division typically hosts or co-hosts around 50 invited and contributed sessions. DAP has a commanding presence—typically accounting for about 1/6 of the April Meeting’s total content —and every year brings difficult decisions about which research areas to highlight. “There is such a broad set of topics in astrophysics that we can’t hope to cover it all,” Fryer noted.

This year’s April Meeting is right around the corner, slated for April 9-12 in a hybrid format featuring in-person sessions in New York as well as a virtual option. Fryer acknowledged that the option for remote meeting attendance has emerged as one of the unexpected silver linings of the COVID-19 pandemic, allowing meeting attendees to catch up on recorded versions of sessions they missed or could not attend due to concurrent scheduling with other talks. That said, the DAP community is eager to return to in-person experiences as soon as the public health situation allows. “The best way to build collaborations with people outside your institution is through the social aspect of in-person meetings,” Fryer explained. “This is especially important for young scientists.”

Looking forward, the DAP executive committee’s goals for the division involve capitalizing on the unique ability of astrophysics to spark public interest in science. “We like to joke that astrophysics is the gateway drug for getting people interested in physics,” said Fryer. He explained that in public outreach efforts, astronomical phenomena—neutron star mergers or supermassive black holes, for instance—can be an excellent jumping off point for discussing some of the most interesting questions in physics. For example, a non-scientist may not immediately appreciate why researchers are excited about (and why hundreds of millions of dollars have been invested in) the newly constructed Facility for Rare Isotope Beams, but their curiosity could be piqued if the discussion is framed in terms of the project’s relevance to understanding the Big Bang and the forces that shaped the early history of the universe. “Getting the public interested in physics is critical—both for securing funding and for an educated society,” Fryer elaborated. “If astrophysics can help spark interest in more physics fields, that’s what I would like to see.”

Promoting the participation of women and under-represented minorities in the astrophysics community is another key priority within the division. DAP is composed of over 20% women, placing it among the top three APS divisions for gender diversity, but still with ample room for growth. DAP also benefits from strong diversity at the leadership level: Men and women are equally represented in DAP’s four chair line positions, and women account for an impressive 7 out of 11 members on the executive committee as a whole. In a hopeful trend, much of DAP’s recent growth has come from a new and more diverse generation of students and early-career scientists. As it currently stands, nearly 50% of DAP members are undergraduate or graduate students.

Overall, DAP stands out as a close and collaborative community at the cutting edge of one of the most high-profile and dynamic areas in physics. As Fryer put it, “If you’re doing astronomy and you’re trying to build ties with plasma physicists, nuclear physicists, and gravitational physicists, DAP is the conduit. Likewise, if you’re a physicist who wants to broaden your impact on astronomy, DAP is also there to help you.”

More information on this unit can be found on the DAP website.

The author is a freelance writer in Stockholm, Sweden.

Note: Physical Review D has recently expanded its coverage of astrophysics and astronomy with the appointment of a new Associate Editor, Enrico Ramirez-Ruiz, Professor and the Vera Rubin Presidential Chair of Astronomy and Astrophysics at the University of California, Santa Cruz.