About

Ashley Villar is an Assistant Professor of Astronomy at the Harvard Department of Astronomy, affiliated with the Center for Astrophysics | Harvard & Smithsonian. Her research interests include theoretical and observational studies of extragalactic transients, such as core-collapse supernovae and kilonovae. She focuses on developing statistical and deep learning methodologies for wide-field surveys, including the Vera C. Rubin Observatory's Legacy Survey of Space and Time and the Nancy Grace Roman Observatory. Dr. Villar received her B.S. in Physics from MIT in 2014 and her Ph.D. in Astronomy and Astrophysics from Harvard University in 2020. She was a Simons Junior Postdoctoral Fellow at Columbia University from 2020 to 2021 and served as a faculty member at Penn State University from 2021 to 2023 before joining Harvard's faculty in 2023.

Research topics

• Physics
• Astronomy
• Computer Security
• Computer Science
• Data Mining
• Linguistics
• Data science
• Cartography
• Astrophysics
• Geography
• Philosophy
• Astrobiology
• Art history
• History
• Database
• Optics

Selected publications

• Recommendations for Early Definition Science with the Nancy Grace Roman Space Telescope

  arXiv (Cornell University) · 2024 · 3 citations

  Senior authorCorresponding
  • Astronomy
  • History
  • Astrobiology

  The Nancy Grace Roman Space Telescope (Roman), NASA's next flagship observatory, has significant mission time to be spent on surveys for general astrophysics in addition to its three core community surveys. We considered what types of observations outside the core surveys would most benefit from early definition, given 700 hours of mission time in the first two years of Roman's operation. We recommend that a survey of the Galactic plane be defined early, based on the broad range of stakeholders for such a survey, the added scientific value of a first pass to obtain a baseline for proper motions complementary to Gaia's, and the significant potential synergies with ground-based surveys, notably the Legacy Survey of Space and Time (LSST) on Rubin. We also found strong motivation to follow a community definition process for ultra-deep observations with Roman.

  DOI

• A Negative Long Lag from the Optical to the UV Continuum in Fairall 9

  The Astrophysical Journal · 2023 · 17 citations

  Senior authorCorresponding
  • Physics
  • Astrophysics
  • Astronomy

  Abstract We report the detection of a long-timescale negative lag, where the blue bands lag the red bands, in the nearby Seyfert 1 galaxy Fairall 9, with two independent methods. Active Galactic Nuclei (AGNs) light curves show variability over a wide range of timescales. By measuring time lags between different wavelengths, the otherwise inaccessible structure and kinematics of the accretion disk can be studied. One common approach, reverberation mapping, quantifies the continuum and line lags moving outward through the disk at the light-travel time, revealing the size and temperature profile of the disk. Inspired by numerical simulations, we expect longer lags to exist in AGN light curves that travel inward on longer timescales, tracing the accretion process itself. By analyzing AGN light curves in both temporal and frequency space, we report the detection of long-timescale lags (∼−70 days) in Fairall 9 that propagate in the opposite direction to the reverberation lag. The short continuum lag (<10 days) is also detected and is consistent with reverberation lags reported in the literature. When fitting the longer lag as a function of frequency with a model motivated by the thin disk model, we find that the disk scale height likely increases outward in the disk. This detection raises the exciting prospect of mapping accretion disk structures across a wide range of AGN parameters.

  DOI

• From Data to Software to Science with the Rubin Observatory LSST

  arXiv (Cornell University) · 2022 · 3 citations

  • Computer Science
  • Computer Science
  • Data science

  The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) dataset will dramatically alter our understanding of the Universe, from the origins of the Solar System to the nature of dark matter and dark energy. Much of this research will depend on the existence of robust, tested, and scalable algorithms, software, and services. Identifying and developing such tools ahead of time has the potential to significantly accelerate the delivery of early science from LSST. Developing these collaboratively, and making them broadly available, can enable more inclusive and equitable collaboration on LSST science. To facilitate such opportunities, a community workshop entitled "From Data to Software to Science with the Rubin Observatory LSST" was organized by the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) and partners, and held at the Flatiron Institute in New York, March 28-30th 2022. The workshop included over 50 in-person attendees invited from over 300 applications. It identified seven key software areas of need: (i) scalable cross-matching and distributed joining of catalogs, (ii) robust photometric redshift determination, (iii) software for determination of selection functions, (iv) frameworks for scalable time-series analyses, (v) services for image access and reprocessing at scale, (vi) object image access (cutouts) and analysis at scale, and (vii) scalable job execution systems. This white paper summarizes the discussions of this workshop. It considers the motivating science use cases, identified cross-cutting algorithms, software, and services, their high-level technical specifications, and the principles of inclusive collaborations needed to develop them. We provide it as a useful roadmap of needs, as well as to spur action and collaboration between groups and individuals looking to develop reusable software for early LSST science.

  PublisherOA PDFDOI

Frequent coauthors

• B. Tucker

  33 shared

• Daniel Kasen

  32 shared

• A. Rest

  31 shared

• P. Garnavich

  University of Notre Dame

  25 shared

• E. Shaya

  25 shared

• A. Zenteno

  24 shared

• G. Strampelli

  University of California, Santa Barbara

  23 shared

• R. F. Mushotzky

  University of Maryland, College Park

  22 shared

Labs

• Center for Astrophysics | Harvard & SmithsonianPI

Education

• Ph.D., Astronomy

  Harvard University

  2010

• B.A., Physics

  Harvard University

  2005

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