This is the unofficial website of the NSF AAPF program, run by the fellows themselves. For official information about the fellowship, please go to the NSF program announcement.
This year's AAPF symposium will be held from Sunday 7 Jan 1:00 PM - Monday 8 Jan 5:15 PM in the Potomac Ballroom 3 at the Gaylord National Harbor Resort & Convention Center prior to the 231st meeting of the American Astronomical Society.
We encourage all AAS attendees to come to our symposium! However we suggest you arrive at or after the 3:00 PM coffee break on Sunday, since the first two hours will be mainly NSF AAPF logistics and internal discussion.
Participants are required to abide by the AAS Anti-Harrassment Policy and the Guide to AAS Meeting Etiquette
Accessibility: We are committed to making this symposium accessible to everybody. Please see the following link for more information: AAS 231 Accessibility.
Lucianne Walkowicz, Blumberg Chair of Astrobiology at the Library of Congress
Choose Your Own Adventure: Developing A Values-Oriented Framework for Your Career
We’ve all heard how academia evaluates our work: papers, papers, and… more papers. While academic publishing is an essential part of disseminating research results, it is only one activity amongst many that make up a career (or for that matter, a life). In this talk, I offer some practical advice for thinking about one’s work within the larger frame of your personal values and goals. While I will draw examples from my own career, I hope to offer listeners guidance in articulating what is important to them, aligning their career choices with those values, and establishing metrics that go beyond the h-index.
Alex Young, Associate Director for Science in the Heliophysics Science Division of NASA's Goddard Space Flight Center
The Importance of Outreach and Communication for Our Science: A Case Study with the 2017 Solar Eclipse.
This schedule is subject to change All times Eastern. Click on the speaker name for their professional biography. Click on the talk title to scroll down to the abstract.
Cosmology: Development of the next-generation POLARBEAR experiment
Darcy Barron
POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012, and the POLARBEAR team has published a series of results from its first season of observations, including the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. Recently, we released an improved measurement of the B-mode polarization power spectrum, improving our band-power uncertainties by a factor of two, by adding new data from our second observing season and re-analyzing the combined data set. To further improve on these measurements, POLARBEAR is expanding to include an additional two telescopes with multi-chroic receivers observing at 95, 150, 220, and 270 GHz, known as the Simons Array. With high sensitivity and large sky coverage, the Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds.The Advancing Space Science through Undergraduate Research Experience (ASSURE) summer REU program is an NSF-funded REU site at the Space Sciences Lab at UC Berkeley that first started in summer 2014. The program recruits students from all STEM majors, targeting underserved students including community college students and first-generation college students. The students have little or no research experience and a wide variety of academic backgrounds, and the program starts with an intensive first week of introductory lectures and tutorials, including hands-on experience with software and hardware based on the same fundamentals that go into the development of the POLARBEAR cameras.
Galaxies: Working With High School and Community College Students on the TIME Instrument to Strengthen Ties Between Education and Research
Abigail Crites
I will discuss TIME, a mm-wavelength camera being designed to study the epoch of reionization and the progress we made in the summer of 2017 with a cohort of 6 students, including high school and community college students. I will discuss each of of the student projects and how they contributed to the development of the TIME instrument. Example of projects include improving cryogenics for the instrument, temperature calibration, COMSOL simulations, and building a Helmholtz coil to test magnetic susceptibility of the instrument.
Cosmology: Next Generation Radio Observatories with Direct Imaging Correlators
Adam Beardsley
Low frequency radio observatories are pushing the limits of high performance computing to process enormous data rates from many antenna elements. The migration to many small antennas is motivated by the need for high sensitivity, wide field surveys for precision cosmology and broad transient searches. But as arrays grow to thousands of antennas, Moore's law will not be sufficient to keep up with the computational requirements. I will present the E-field Parallel Imaging Correlator (EPIC), which is a direct imaging solution to the data crunch predicament. EPIC alleviates the computational strain for future arrays, while simultaneously opening a window to high time resolution images. A software implementation of EPIC has shown its feasibility, and we are in the process of deploying a GPU version on the Long Wavelength Array in Sevilletta, NM.
Stars: Age-dating Sun-like stars
Jason Curtis
Sun-like dwarf stars slowly grow bigger and brighter over time, which makes it difficult to infer how old they are by comparison to evolutionary model predictions, but they do reveal their age through other ways like the steady loss of angular momentum. Magnetic braking causes these stars to spin down over time, which in turn weakens their magnetic activity. A star's birthday is also encoded in its chemical abundance pattern. Combining these diagnostics allows us to cross-validate the empirical relationships and apply them to isolated stars. Tuning these spin-down and chemical clocks requires well-characterized touchstone stars. I will discuss the observations conducted by the Kepler/K2 mission, the acquisition of high-quality spectroscopy of nearby solar twins and other field stars in search of exoplanets, and the establishment of the 3 Gyr Ruprecht 147 star cluster as a new benchmark, then demonstrate how these advances help us improve our age-dating techniques.
Stars: Using Stellar Activity to Measure the Ages of Stars
James Davenport
While Kepler/K2 has observed almost 400,000 stars in search of exoplanets, it has amassed a revolutionary dataset for the study of stellar magnetism. Rates of stellar flares have been determined for thousands of low-mass stars, and produced direct evidence for the evolution of flare activity with stellar age. I will review how we constrain the rate of stellar flares for every star in the Kepler dataset, and describe the model for flare rate evolution I have developed as part of my NSF Fellowship research.
Cosmology: Realizing the Promise of 21 cm Cosmology with HERA
Josh Dillon
Realizing the promise of 21 cm cosmology to provide an exquisite probe of astrophysics and cosmology during the "Cosmic Dawn" and the epoch of reionization (EoR) has proven extremely challenging. We're looking for a small signal buried under foregrounds orders of magnitude brighter. We need large interferometers, precisely calibrated, producing mountains of data to have any shot of seeing the signal. In this talk, I will survey the new analysis techniques we've developed and the progress we've made toward separating the 21 cm signal from foregrounds using current generation interferometers, the Precision Array for Probing the Epoch of Reionization and the Murchison Widefield Array. Then I will discuss how the progress we've made is shaping the Hydrogen Epoch of Reionization Array (HERA), a purpose-built interferometer currently under construction that is designed not just to detect the EoR but to characterize its evolution and to push into the pre-reionization epoch.
Planets: Inreach vs. Outreach: The Need for Unconventional Education Events
Cameron Hummels
Many traditional outreach efforts are very successful at "inreach", reaching members of our society who are already convinced of the utility of science. However, it is crucial and significantly more difficult to perform true "outreach" by connecting with people ambivalent about the utility of science at all. Engaging these audiences requires a fundamental rethinking of how and why we educate the public overall. I will discuss some ways to perform both inreach and outreach, based on my experiences running Caltech and Columbia's astronomy outreach programs over the last decade.
Galaxies: Star Formation on the Edge & Multicultural Milky Way
Karen Knierman
Mergers between galaxies of different mass are very common in the universe and may affect the majority of galaxies including our own Milky Way galaxy. The debris produced in these minor mergers is a unique place to study the factors that influence star formation since it is away from the dense centers of the mergers. Due to the lower pressures and densities in the tidal debris, this study probes the lower bounds of where star formation is possible. We use star formation tracers such as young star cluster populations and H-alpha and CII emission to determine the different factors that may influence star formation in tidal debris. These tracers were compared to the reservoirs of molecular and neutral gas available for star formation to estimate the star formation efficiency (SFE). The SFR in tidal debris can reach up to 50% of the total star formation in the system. The SFE of tidal tails in minor mergers can range over orders of magnitude on both local and global scales, and include several star forming regions with higher than normal SFE. From the tidal debris environments in our study, this variance appears to stem from the formation conditions of the debris. New results from the first survey of molecular hydrogen in minor merger tidal debris will be presented. Current surveys of the 2.12 micron line of molecular hydrogen, CO(1-0), and HI for 15 minor mergers, are providing a larger sample of environments to study the threshold for star formation that can inform star formation models, particularly at low densities. The astronomy outreach initiative, Multicultural Milky Way, partners the School of Earth and Space Exploration (SESE) at Arizona State University (ASU) with under-served populations in Arizona in learning about our Milky Way and other galaxies. Arizona is home to many diverse populations with rich cultural histories such as Mayan, Navajo, and Apache. Linking astronomy practiced by one's indigenous culture to that of Western astronomy may increase the interest in science. Through multicultural planetarium shows and associated hands-on activities, under-served students and families will learn how the Milky Way is represented in different cultures and about the science of galaxies. New planetarium shows using the Mesa Community College (MCC) Digital Planetarium and STARLAB portable planetarium explore how the Milky Way is interpreted in different cultures. STARLAB shows and associated new hands-on activities have been featured during school visits, teacher trainings, and Community Astronomy Nights around Arizona. For authentic assessment, evaluation techniques and procedures were developed.
Galaxies: Pushing Galaxy SED Models to the Limit: A Wealth of New Insights with Prospector
Joel Leja
Broadband photometry of galaxies measures an unresolved mix of complex stellar populations, gas, and dust. Interpreting data affected by such a large range of physical processes is a challenge for models. As a result, properties derived from modeling galaxy photometry are systematically uncertain by a factor of two or more. Yet, answering key questions in the field now requires higher accuracy than this. Here, I will present a new model framework specifically designed for these complexities. This model, Prospector-α, includes dust attenuation and re-radiation, a flexible attenuation curve, nebular emission, stellar metallicity, obscured AGN, and a 6-component nonparametric star formation history. The flexibility and range of the parameter space, coupled with MCMC sampling within the Prospector inference framework, is designed to provide unbiased parameters and realistic error bars. I will present a careful assessment of the accuracy of this model on a well-studied sample of nearby galaxies, and discuss prospects for the application of Prospector-α to galaxies in the distant Universe.
Cosmology: MassiveNuS: Cosmology with massive neutrinos
Jia Liu
The non-zero mass of neutrinos suppresses the growth of cosmic structure on small scales. The level of suppression depends on the sum of the masses of the three active neutrino species, to lowest order. As such, the evolution of large-scale structure is a promising tool to constrain the total mass of neutrinos and possibly shed light on the mass hierarchy. To understand these effects, we run a large suite of N-body simulations that include the massive neutrinos using an analytic linear-response approximation: the Cosmological Massive Neutrino Simulations (MassiveNuS). I will present the key results from this project.
Education: The Prison Teaching Initiative in New Jersey
Jia Liu
The Prison Teaching Initiative (PTI) aims to reduce incarceration rates in New Jersey by increasing access to post-secondary education in state prisons. I will share the brief history of this program as well as my classroom experience.
Planets: Debris Disks as Probes of Planetary System Evolution
Meredith MacGregor
At least 20% of nearby main sequence stars are surrounded by disks of dusty material resulting from the collisional erosion of planetesimals, larger bodies similar to asteroids and comets in our own Solar System. The resulting dust can be observed via scattered light at visible to near-infrared wavelengths or thermal emission at mid-infrared to millimeter wavelengths. Since the dust-producing planetesimals are expected to persist in stable regions like belts and resonances, the locations, morphologies, and physical properties of dust in these debris disks provide probes of planet formation and subsequent dynamical evolution. Observations at millimeter wavelengths are especially critical to our understanding of these systems, since the large grains that dominate emission at these long wavelengths do not travel far from their origin and therefore reliably trace the underlying planetesimal distribution. I will present new resolved ALMA observations of the Fomalhaut, HD 32297, and HD 61005 systems that constrain the structure of these well-known debris disks. The observations of Fomalhaut have enabled the first conclusive detection of apocenter glow, a brightness asymmetry due to a surface density enhancement at apocenter resulting from the disk'۪s significant eccentricity, e = 0.12+/-0.01. For HD 32297 and HD 61005, these new observations provide some of the first evidence that large grains may populate extended halos typically assumed to only be composed of small grains visible in scattered light.
Stars: The UV Bright Stellar Population in the Center of M31
Philip Rosenfield
The ability to correctly model UV stellar populations is critical for interpreting galaxy observations from the optical through the far-IR, due to their impact on the production of emission lines and on the heating of dust. Although massive main sequence stars are the most widely known source of UV emission, older stellar populations also host UV-emitting stars that produce significant flux (detectable as a “UV-excess”) in dormant elliptical galaxies or spiral galaxy bulges.
The detection of UV-excess is a direct probe of early galaxy evolution. In old stellar populations, the UV flux is emitted by low mass (<1 Msun) horizontal branch (HB) stars and their hot luminous descendants. Because post-HB stars are the evolved progeny of long-lived, low-mass main sequence stars, they directly probe the earliest epochs of star formation.
I will present preliminary results of an HST survey of the center of the M31 where we are producing the first UV catalog of these hot evolved stars as a function of galaxy radius, with the quality required to constrain their evolution.
Education: PRoboT: The Pasadena High School Robotic Telescope Project
Garreth Ruane
The Pasadena High School Robotic Telescope (PRobot) is an 8 inch Schmidt-Cassegrain telescope assembled, and operated by Pasadena High School students. Located on the rooftop of the Cahill Center for Astronomy and Astrophysics at California Institute of Technology, PRoboT is routinely used for student projects that involve imaging stars, galaxies, planets, and the sun. Students have developed methods to operate all aspects of the telescope software remotely with minimal on-site interaction. Current work seeks to quantify the photometric accuracy of PRoboT with the ultimate goal of detecting known exoplanet transits.
Planets: Imaging Protoplanets: Observing Transition Disks with Non-Redundant Masking
Steph Sallum
Understanding the mechanisms by which planets form requires direct observations of protoplanets themselves. Transition disks, protoplanetary disks with inner clearings that may be shaped by forming planets, are the most promising targets for these studies. While protoplanets are expected to have low infrared contrasts compared to mature exoplanets, the large distances to most transition disks necessitate novel techniques even beyond coronography to make these detections. Non-redundant masking (NRM), which transforms a conventional telescope into an interferometric array, is well posed to detect protoplanets in transition disk clearings. I will present the results of NRM observations of transition disks, as well as strategies for distinguishing accreting protoplanets from light scattered by disk material. I will also discuss potential applications of NRM and related techniques on next generation facilities.
Education: Astronomy Sound of the Month
Greg Salvesen
The Astronomy Sound of the Month website (AstroSoM.com) is scheduled for launch on January 1st, 2018. Each Astro SoM installment will use sound to highlight astrophysics research in a fun way that is accessible to a non-scientific audience. Data sonification --- the use of sound to portray data --- can be more than just a gimmick to generate public excitement about astronomy. Indeed, sound is a multi-dimensional medium that can complement traditional visual representations of a dataset. Furthermore, data sonification allows people with visual impairments to experience the excitement of astronomy, which is an inherently visual science. In this talk, I will show off the new website, give sneak peeks of upcoming Astro SoMs, and solicit data sonification contributions from the astrophysics research community.
Education: How do we include young girls in science?
Rukmani Vijayaraghavan
For the last two years as an AAPF, I have run the "Girls Exploring the Universe" camp for middle school girls in the Charlottesville - Albemarle area. This camp consists of a series of curiosity driven, hands-on activities in areas ranging from exploring Mars to the expansion of the Universe, meeting with other women astronomers, and a field trip to Green Bank Observatory. Through this camp, I hope to have these girls see themselves as future scientists, to motivate them to pursue science and math at a critical juncture in their school years. While of course it is important to support these educational and outreach activities, and ideally on a much broader level, we must also ensure that our field is inclusive and supportive of these girls if and when they decide to eventually pursue a career in astronomy and science. What are our obligations as today's scientists to best do that?
Stars: How Stars Get Their Spots: Toward Linking Dynamo Action and Magnetic Flux
Maria Weber
Our understanding of stellar magnetism has historically been driven by the phenomena we have observed of our own Sun. Yet, as we amass datasets for an increasing number of stars, it is clear that there is a wide variety of stellar magnetic behavior. Establishing the details of magnetic flux emergence plays a key role in deciphering stellar dynamos and observed starspot properties. In the solar context, insight into this process has been obtained by assuming the magnetism giving rise to sunspots consists partly of idealized, buoyantly rising thin flux tubes (TFTs). Here, I present multiple sets of TFT simulations in rotating spherical shells of convection representative of both sun-like stars with outer convection zones and fully convective M dwarfs. The solar simulations reproduce sunspot observables such as low-latitude emergence, tilting action toward the equator following the Joy's Law trend, and a phenomenon akin to active longitudes. In the fully convective M dwarf simulations, the expected starspot latitudes deviate from the solar trend, favoring significantly poleward latitudes unless the differential rotation is sufficiently prograde or the magnetic field is strongly super-equipartition. Only recently have convective dynamo simulations been able to self-consistently capture some elements of magnetic flux emergence. I comment on how the rise of such magnetic structures compares to the computationally inexpensive TFT approach, discuss the implications of including/excluding a tachocline of shear in the these models, and outline plans for 3D dynamo simulations spanning the transition from partially-to-fully convective stars.
Galaxies: The emergence of quenched galaxies in the era of JWST
Christina Williams
The cessation of star-formation in galaxies remains poorly understood, despite being one of the most influential events in galaxy evolution. It is now known that high stellar mass density is strongly associated with this process at z~2-3, but the reason for this association is also poorly understood. Does high stellar density have a causal link with quenching, or is it a side effect of rapid growth in the early Universe? I will present new spectroscopic studies of stellar ages, molecular gas content, and feedback signatures that collectively provide evidence in favor of the latter scenario: compact galaxies grow fast in the first few billion years, but their high stellar density does not directly cause quenching. Understanding the early evolutionary development of the first quenched galaxies at z>3 is a major science goal of JWST, and I will discuss how future extragalactic surveys with this groundbreaking facility will resolve outstanding questions about their formation scenarios.
Planets: Refractory Abundances of Terrestrial Planets and Their Stars: Testing [Si/Fe] Correlations with TESS and PLATO
Angie Wolfgang
In standard models for planet formation, solid material in protoplanetary disks coagulate and collide to form rocky bodies. It therefore seems reasonable to assume that their chemical composition will follow the abundances of refractory elements, such as Si and Fe, in the host star, which has also accreted material from the disk. Backed by planet formation simulations which validate this assumption, planetary internal structure models have begun to use stellar abundances to break degeneracies in low-mass planet compositions inferred only from mass and radius. Inconveniently, our own Solar System contradicts this approach, as its terrestrial bodies exhibit a range of rock/iron ratios and the Sun's [Si/Fe] ratio is offset from the mean planetary [Si/Fe]. In this work, we explore what number and quality of observations we need to empirically measure the exoplanet-star [Si/Fe] correlation, given future transit missions, RV follow-up, and stellar characterization. Specifically, we generate synthetic datasets of terrestrial planet masses and radii and host star abundances assuming that the planets' bulk [Si/Fe] ratio exactly tracks that of their host stars. We assign measurement uncertainties corresponding to expected precisions for TESS, PLATO, Gaia, and future RV instrumentation, and then invert the problem to infer the planet-star [Si/Fe] correlation given these observational constraints. Comparing the result to the generated truth, we find that 1% precision on the planet radii is needed to test whether [Si/Fe] ratios are correlated between exoplanet and host star. On the other hand, lower precisions can test for systematic offsets between planet and star [Si/Fe], which can constrain the importance of giant impacts for extrasolar terrestrial planet formation.
Summer App Space, A Six Week Apprenticeship in Computational Space Sciences
Christine Moran
Summer App Space ran June 26-August 4, 2017. Summer App Space was a paid apprenticeship for LA students and teachers to learn to program while getting paid to do space-related research. High school students were paid to attend a six-week school learning to program in Python, twenty hours per week. These students were recruited from the local area with a wide net cast: a simple application that took less than a minute to fill out was followed on by a fifteen minute technical and interpersonal interview for every applicant. Out of 120 students, 12 were selected for this elite program. Four weeks were lecture and lab based, and the last two weeks were project based incorporating a deliverable research result and entrepreneurial style teams. For the last two weeks area high school teachers, who self-studied Python, joined and students formed three teams working towards projects to present on our Demo Day August 4 to a panel of judges and industry experts. High school teachers participated with the goal to take the curriculum back into their classroom reaching even more students. Throughout the program every Thursday we hosted a speaker series and student driven Q&A open to the entire Caltech community. This innovation speaker series invites industry leaders in astronomy, astrophysics, aerospace, software engineering, investment, and entrepreneurship (startups) to share their journey and technical knowledge. This series allowed Summer App Space students and the Caltech community to network with a wide range of successful professionals. Summer App Space has open sourced, a custom textbook for the course introducing python and data analysis, a series of python notebooks suitable for weekly assignments, as well as the lecture slides, lecture videos, and videos of the Innovation Speakers series. This content is useful not only for similar programs, but also in training undergraduate researchers in the fundamentals offloading work from research mentors. In this talk, I will discuss the program as well as practical information like finances, logistics, recruiting volunteers, recruiting students, and publicity, as well as our unique interviewing strategy, which resulted in an excellent, diverse class.