Publications
First-author
- A. K. Gautam, T. Do, A. M. Ghez, et al. An Estimate of the Binary Star Fraction Among Young Stars at the Galactic Center: Possible Evidence of a Radial Dependence
Journal (open access): ApJ, 964:164, 2024
Preprint (open access): arXiv:2401.12555 - A. K. Gautam, T. Do, A. M. Ghez, et al. An Adaptive Optics Survey of Stellar Variability at the Galactic Center
Journal: ApJ, 871:103, 2019
Preprint (open access): arXiv:1811.04898
Co-authored
- H. Paugnat, T. Do, A. K. Gautam, et al. New Evidence for a Flux-independent Spectral Index of Sgr A* in the Near-infrared
Journal: ApJ [in press]
Preprint (open access): arXiv:2411.11966 - Z. Haggard, A. M. Ghez, S. Sakai, A. K. Gautam, et al. The Galactic Center in Color: Measuring Extinction with High-Proper-Motion Stars
Journal (Open Access): AJ, 168:166, 2024
Preprint (open access): arXiv:2408.03467 - G. C. Weldon, et al, incl. A. K. Gautam. Near-infrared Flux Distribution of Sgr A* from 2005–2022: Evidence for an Enhanced Accretion Episode in 2019
Journal (open access): ApJL, 954:L33, 2023
Preprint (open access): arXiv:2308.09749 - M. S. R. Freeman, J. R. Lu, J. Lyke, A. K. Gautam, et al. An Optical Distortion Solution for the Keck I OSIRIS Imager
Journal (open access): AJ, 166:125, 2023 - S. Jia, et al, incl. A. K. Gautam. Stellar Populations in the Central 0.5 pc of Our Galaxy. III. The Dynamical Substructures
Journal (open access): ApJ, 949:18, 2023
Preprint (open access): arXiv:2302.02040 - D. S. Chu, T. Do, A. M. Ghez, A. K. Gautam, et al. Evidence of a Decreased Binary Fraction for Massive Stars within 20 milliparsecs of the Supermassive Black Hole at the Galactic Center
Journal (open access): ApJ, 948:94, 2023
Preprint (open access): arXiv:2303.16977 - A. Ciurlo, et al, incl. A. K. Gautam. The Swansong of the Galactic Center Source X7: An Extreme Example of Tidal Evolution near the Supermassive Black Hole
Journal (open access): ApJ, 944:136, 2023
Preprint (open access): arXiv:2301.06562 - S. K. Terry, et al, incl. A. K. Gautam. AIROPA IV: Validating point spread function reconstruction on various science cases
Journal (open access): JATIS, 9,1,018003, 2023
Preprint (open access): arXiv:2209.05489 - E. Ramey, et al, incl. A. K. Gautam. Analyzing long-term performance of the Keck-II adaptive optics system
Journal: JATIS, 8,2,028004, 2022 - S. C. Rose, S. Naoz, A. K. Gautam, et al. On Socially Distant Neighbors: Using Binaries to Constrain the Density of Objects in the Galactic Center
Journal: ApJ, 904:2, 2020
Preprint (open access): arXiv: 2008.06512 - M. W. Hosek Jr., J. R. Lu, C. Y. Lam, A. K. Gautam, et al. SPISEA: A Python-Based Simple Stellar Population Synthesis Code for Star Clusters
Journal: AJ, 160:143, 2020
Preprint (open access): arXiv:2006.06691 - A. Hees, et al, incl. A. K. Gautam. Search for a Variation of the Fine Structure Constant around the Supermassive Black Hole in Our Galactic Center
Journal: PRL, 124, 081101, 2020
Preprint (open access): arXiv:2002.11567 - Z. Chen, et al, incl. A. K. Gautam. Consistency of the Infrared Variability of Sgr A* over 22 yr
Journal: ApJL, 882:L28, 2019
Preprint (open access): arXiv:1908.08066 - T. Do, G. Witzel, A. K. Gautam, et al. Unprecedented Near-infrared Brightness and Variability of Sgr A*
Journal: ApJL, 882:L27, 2019
Preprint (open access): arXiv:1908.01777 - T. Do, et al, incl. A. K. Gautam. Relativistic redshift of the star S0-2 orbiting the Galactic center supermassive black hole
Journal: Science, 16 Aug 2019
Preprint (open access): arXiv:1907.10731 - S. Jia, J. R. Lu, S. Sakai, A. K. Gautam, et al. The Galactic Center: Improved Relative Astrometry for Velocities, Accelerations, and Orbits near the Supermassive Black Hole
Journal: ApJ, 873:9, 2019
Preprint (open access): arXiv:1902.02491 - S. Sakai, et al, incl. A. K. Gautam. The Galactic Center: An Improved Astrometric Reference Frame for Stellar Orbits around the Supermassive Black Hole
Journal: ApJ, 873:65, 2019
Preprint (open access): arXiv:1901.08685 - D. S. Chu, et al, incl. A. K. Gautam. Investigating the Binarity of S0-2
Journal: ApJ, 854:12, 2018
Preprint (open access): arXiv:1709.04890
Conference talks and proceedings
- A. K. Gautam, T. Do, A. M. Ghez, et al. A high stellar binary fraction among the young, massive stars in the central half parsec
Galactic Center Workshop 2023, 2023 April, Talk - A. K. Gautam, T. Do, A. M. Ghez, et al. Understanding the star formation and dynamical histories of the Milky Way Galactic center with stellar binaries
AAS 235, 2020 January, Thesis Talk - A. K. Gautam, T. Do, A. M. Ghez, et al. Constraints on the Density of the Dark Cusp Around the Galactic Center Supermassive Black Hole With a Newly Detected, Old, ≈79 Day Period Stellar Binary System
Galactic Center Workshop 2019, 2019 October, Poster - A. K. Gautam, T. Do, A. M. Ghez, et al. Photometric detection of a candidate low-mass giant binary system at the Milky Way Galactic Center
AAS 231, 2018 January, Talk - A. K. Gautam, T. Do, A. M. Ghez, et al. Constraining the Variability and Binary Fraction of Galactic Center Young Stars
IAU Symposium 322, 2016 July, Poster - A. K. Gautam, A. Siemion, E. J. Korpela, et al. SETI Searches for Radio Transients from Kepler Field Planets and Astropulse Candidates
AAS 224, 2014 June, Talk
Current Research
Stellar and dynamical environment
of the Milky Way Galactic center
My projects primarily study the stellar population and dynamical environment of the Milky Way Galactic center (GC). The center of the galaxy is a unique laboratory that allows us to study how stars form in an extreme environment and how the presence of a supermassive black hole affects the dynamics in a star cluster.
My PhD thesis research projects have largely used near-infrared adaptive optics imaging data of the Galactic center taken using the Keck II telescope. Through my projects, I’ve developed a methodology to extract precise photometry from the UCLA Galactic Center Group’s AO imaging dataset spanning over 13 years. Precise photometry of the GC stars presents a valuable way to help answer the broad questions of my thesis, by understanding the nature of the stars at the Galactic center and the environment they inhabit.
One way I’m using photometry data is by detecting binary star systems to help answer some open questions about the formation of GC stars and dynamical history of the GC. The GC has a surprising collection of young stars in close proximity to the central black hole, and a distribution of old stars that don’t quite match theoretical expectations. Binary star systems are valuable ways to help us better understand both open questions. The number, distribution, and properties of binary star systems can tell us about the star formation of the environment. And the survival of a binary star system can tell us about what kinds of dynamical environments the system has encountered over its lifetime.
This telescope is where most of my PhD research data came from!
Conference Research Pages
- 2019 October, Galactic Center Workshop 2019, Yokohama, Japan: Constraints on Dark Cusp from an Old Binary System at Galactic Center
- 2019 September, Keck Science Meeting, UCLA: Constraints on Dark Cusp from an Old Binary System at Galactic Center
Previous Research
Transient Search
I worked on several projects to search for transients in radio data with the Berkeley SETI Research Center (BSRC). This included radio observations of Kepler Objects of Interest (KOI) in the Kepler Field, re-observations of candidates from the Astropulse survey, and millimeter observations of the galactic center. The goal was to search for SETI signals and signals from natural radio transients such as pulsars, FRBs, and RRATs.
(2011 – 2014)
Analysis of the Guitar Nebula and PSR B2224+65
I worked on analyzing multiple epochs of radio, optical, and x-ray data of the region surrounding the pulsar B2224+65 with Professor Jim Cordes and Dr. Shami Chatterjee at Cornell University. This included the very interesting bow-shock nebula created by the pulsar known as the Guitar Nebula. The work was conducted at Cornell University’s 2012 Astronomy REU Program.
(Summer 2012)
Sgr A* VLBI Calibration
I worked on calibration work for VLBI (Very Long Baseline Interferometry) observations of Sgr A* at millimeter wavelengths with Dr. Melvyn Wright at UC Berkeley.
(Summer 2011)