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Postdocs

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Stacey Alberts

Ph.D., 2014, University of Massachusetts, Amherst
Areas of Interest: Galaxy Formation and Evolution, Galaxy Clusters, Star Formation, Active Galactic Nuclei, High Redshift Galaxies

Stacey's research focuses on galaxy evolution in the context of local environment through studies of massive galaxy clusters out to high redshift. Through multi-wavelength observations focusing on the mid-infrared to submillimeter, she characterizes star formation and AGN in cluster and field galaxies up to z~2 in order to determine how environment shapes galaxy properties and results in the quenched nature of cluster galaxies today. At Arizona, she has joined the Mid-Infrared Instrument (MIRI) team and is involved in planning early observations in preparation for the launch of the James Webb Space Telescope.

Jennifer Andrews

Ph.D., 2011, Louisiana State University
Areas of Interest: Core-Collapse SNe, Evolved Massive Stars, Stellar Clusters, Initial Mass Function

Jennifer is involved in mapping the late-time evolution of massive stars using multi-wavelength observations of their interaction with their surrounding environment. This includes optical and IR light echoes and spectral changes due to circumstellar interaction. She is also interested in how, when, and where dust is formed in CCSNe, particularly with regards to mass loss from the progenitor star.

Nicholas Ballering

Ph.D , 2016, University of Arizona
Areas of Interest: Circumstellar disks, Planet Formation, Exoplanet Detection and Characterization

Nick uses ALMA to study the mass distribution of protoplanetary disks in stellar clusters to assess their potential for planet formation. He works with professor Josh Eisner and is a member of the Earths in Other Solar Systems team. Nick did his Ph.D. at the UA working with George Rieke to measure the structure and composition of debris disks. He was a regular contributor to the astronomy blog Astrobites from 2012-2014.

Yumi Choi

Ph.D , 2016, University of Washington, Seattle
Areas of Interest: Resolved stellar populations, nearby galaxies, Star Formation, escaping ionizing photons, galactic structures, cosmic reionization.

Yumi Choi's research interests focus on the formation and evolution of galaxies. She studies various galactic physics using resolved stellar populations in nearby galaxies, imaged in multiple wavelengths. During her thesis at UW, she traced galactic structures (e.g., spiral arms, rings) of M81 and M31 and explored their origins. Also, she measured the escape fraction of ionizing photons from NGC 4214, which is an excellent analog of high-z star-forming galaxy. She joined Steward Observatory as a SMASH postdoc.

Pierre Christian

SO Prize Fellow in Theoretical and Computational Astrophysics
Ph.D., 2018, Harvard University
Areas of Interest: Black hole astrophysics and gravitational waves

Pierre is interested in studying the interaction of black holes with its environments, and how such interactions could be used to probe the physics of extreme spacetimes. He is also interested in studying the population and formation of gravitational wave sources, e.g. his latest paper studied how gravitational wave observations can be leveraged to constrain the modification of the black hole mass function due to merging black holes in star clusters. Pierre joined Steward Observatory in the fall 2018 semester.

Steve Ertel

Ph.D., 2012, University of Kiel, Germany
Areas of Interest: Debris Disks, exozodiacal dust, planetary systems, planets around evolved stars, Interferometry, high contrast imaging

Steve is instrument scientist for the Large Binocular Telescope Interferometer (LBTI). His research focuses on the formation and evolution of planetary systems, in particular the study of debris disks and exozodiacal dust (warm and hot dust around main sequence stars). He is also interested in the evolution of planetary systems beyond the main sequence life time of their host stars. He received a PhD from the University of Kiel, Germany. After that followed a post-doc at the University of Grenoble, France, and a Fellowship at ESO Chile where he was support astronomer at the Paranal Observatory and VLTI/PIONIER instrument fellow before he started his position at the LBTI.

Taran Esplin

Peter A. Strittmatter Fellow in Astronomy & Astrophysics
Ph.D., 2017, Pennsylvania State University
Areas of Interest: Nearby Star-forming Regions, Brown Dwarfs, Circumstellar disks, Initial Mass Function, Brown Dwarf Atmospheres

Taran's research has included: searching for the classifying circumstellar disks in nearby star-forming regions, characterizing the photometric variability of the coldest known brown dwarf, measuring a new distortion correction for the Infrared Array Camera on the Spitzer Space Telescope, and determining precise parallaxes for ultra-cool brown dwarfs. He completed his Ph.D. in 2017 advised by Kevin Luhman at Pennsylvania State University. Currently Taran is searching for the least-massive members in nearby star-forming regions as the inaugural Strittmatter Fellow.

Xiao Fang

Ph.D., 2018, Ohio State University
Areas of Interest: Survey Cosmology, Large-Scale Structure, Compact Objects, Hierarchical Systems, stellar dynamics, Type Ia Supernovae

Xiao joined Steward Observatory on September 1, 2018 to work with Prof. Tim Eifler. As a Ph.D. student at Ohio State University, he worked on a broad range of topics, from observational cosmology to compact objects and stellar dynamics. He was also involved in analysis for the upcoming WFIRST mission.

Min Fang

Ph.D., 2011, Heidelberg University
Areas of Interest: Circumstellar disk evolution and accretion behavior of young stars.

Min works in the Steward Observatory and the Lunar and Planetary Laboratory. He studies how the circumstellar disk evolution depends on local environments and stellar properties, while investigating the accretion activities of young stars at different evolutionary stages.

Megan Gralla

Ph.D., 2011, University of Chicago
Areas of Interest: Galaxy Clusters, Active Galactic Nuclei, Dusty star-forming galaxies

Megan studies galaxy clusters and groups, active galactic nuclei, and the relationship between galaxies and their environments. She works with surveys and data sets spanning the radio, millimeter-wavelength, optical and X-ray regimes. Before joining Steward Observatory, Megan worked at Johns Hopkins University and the Smithsonian Astrophysical Observatory.

Kevin Hainline

Ph.D., 2012, UCLA
Areas of Interest: Active Galactic Nuclei, Obscured Quasars in the Context of Galaxy Evolution, high-redshift galaxies

Kevin looks at the relationship between active galactic nuclei and star-forming galaxies, exploring how an active central super-massive black hole grows alongside its host galaxy. His research aims to understand the extent to which obscured AGNs can affect gas throughout their hosts.

Kyle Kaplan

Ph.D., 2017, University of Texas, Austin
Areas of Interest: High resolution spectroscopy in the optical and infrared, the interstellar medium, photodissociation regions, planetary nebulae, molecular hydrogen, feedback from high mass star formation, elemental abundances in nebulae, H II reions, and dust.

Dr. Kaplan graduated with a Ph.D. in Astronomy from the University of Texas at Austin in June 2017. There, he worked with Harriet Dinerstein and Dan Jaffe to study gas clouds out in space surrounding newly born or dying stars. Ultraviolet radiation from the stars excites hydrogen molecules in the gas, causing the molecules to rotate and vibrate. As the molecules slow down, they give off energy in the form of near-infrared radiation. Kyle observed this radiation from the molecules with the high resolution (R~45000) near-infrared spectrograph IGRINS that observes both the H and K bands (1.45-2.45µm) simultaneously. From these observations, I was able to infer the excitation and physical conditions such as the temperature and density within the observed molecular gas. At the University of Arizona, Kaplan will be working with Chad Bender on the high resolution optical NEID spectrograph. He will be helping set up the data reduction pipeline for NEID, which will turn the raw data from stars into precisely measured radial velocities to search for exoplanets.

Sebastiaan Krijt

NASA Hubble Fellow
Ph.D., 2015, Leiden University, The Netherlands
Areas of Interest: Protoplanetary Disks, dust coagulation, Planet Formation

Sebastiaan joined Steward Observatory on September 1, 2018 to work with Prof. Daniel Apai. Sebastiaan uses numerical simulations to study the behavior of dust particles in protoplanetary disks. He is interested in understanding how, where, and when microscopic dust grains coagulate to form km-size planetesimals (the building blocks of planets), and how the dynamical behavior of dust grains influences the chemical composition of the growing solids and the protoplanetary nebula as a whole.

Gwang-Ho Lee

KASI-Arizona Postdoctoral Fellow
Ph.D. in Astronomy, 2017, Seoul National University, Korea
Areas of Interest: Galaxy Formation and Evolution, Environmental Effects on Galaxy Evolution, Galaxy Clusters/ Groups, Post-Starburst Galaxies, Stellar & ISM Properties in Galaxies

Dr. Lee will be joining Steward Observatory in September 2017. Gwang-Ho Lee's research mainly focuses on studying which mechanisms trigger galaxy transition from star-forming galaxies into quiescent galaxies, and what happens during the galaxy transition. During his Ph. D. course, he studied the multi-wavelength properties of galaxies in a full range of environments to understand the environmental effects on galaxy evolution. He is involved in several post-starburst galaxy projects using the Gemini telescope.

Jarron Leisenring

Ph.D., 2011, University of Virginia
Areas of Interest: Protoplanetary Disks, Extrasolar planets, high contrast imaging, IR Instrumentation

Jarron's research focuses on the evolution of protoplanetary disks and how it relates to planet formation. In support of these research goals, Jarron contributes towards the development of IR instrumentation projects such as LBTI/LMIRcam and has most recently joined the JWST NIRCam team as an instrument test scientist.

Michael Lundquist

Areas of Interest: Star Formation, Stellar Clusters, Massive Stars, time domain astronomy, Instrumentation

Michael Lundquist joined Steward Observatory on August 1, 2018. Michael is an observational astronomer with broad research interests. His research background includes studies of classical novae, massive stellar binaries, and intermediate-mass star-forming regions. Michael works with Prof. David Sand as part of the DLT40 supernova survey.

Elena Manjavacas

PhD, Universität Heidelberg, Germany
Areas of Interest: Low-mass stars, Brown Dwarfs, free-floating planets

Elena Manjavacas was born in Mota del Cuervo in Spain. From a young age, she used to admire the clear sky and wondered about the mysteries all those stars were hiding. In 2005, she moved to Madrid to fulfill her dream of becoming an astronomer and studied Physics at Universidad Complutense the Madrid. In 2010, she graduated with a B.A. in Physics, in the specialty of Astrophysics, and received her master’s degree in Astrophysics a year later. Her master’s thesis, “Frequencies and oscillation modes of variable stars in sigma Orionis and NGC 6811", was supervised by Drs. Jose A. Caballero, Orlagh Creevey and Brandon Tingley. She then moved to Heidelberg to start her PhD in Astronomy under the supervision of Prof. Thomas Henning, and Drs. Bertrand Goldman and Sabine Reffert. On February 2015, she defended her PhD thesis entitled "Physical Characterization of Brown Dwarfs". Outside science, Elena is passionate about learning different types of dances, from salsa to belly dance. She also loves swimming and jogging, and enjoy traveling and meeting people with different cultures. Elena speaks Spanish, is fluent in English and German, and has a basic knowledge of French and Italian.

Vivian Miranda

Ph.D., 2015, University of Chicago
Areas of Interest: Dark Energy, Inflation, Cosmic Microwave Background, Weak Lensing, Cluster Cosmology

Vivian Miranda joined Steward Observatory on September 1, 2018 to work with Prof. Elisabeth Krause. Vivian’s research is focused on probing inflation, the epoch of reionization and dark energy with the Cosmic Microwave Background. She has done her Ph.D. at the University of Chicago under the guidance of Prof. Wayne Hu. Vivian is also keen on understanding how extensions of the LCDM model can be constrained via the combination of the CMB with low redshift probes. As a postdoc at University of Pennsylvania, she has developed research on how to test fundamental assumptions about the standard model using model-independent techniques. At the University of Arizona, Vivian intends to dedicate her time to the Dark Energy Survey (DES), in particular, to cluster cosmology and weak lensing. Vivian's work stands on the bridge between theory and data, and she is open to radically new ideas, as long as it can be falsified by either the CMB or the DES/LSST/WFIRST surveys.

Maxwell Moe

NASA Einstein Fellow
Ph.D., 2015, Harvard University
Areas of Interest: Binary Star Formation and Evolution, Eclipsing Binaries, Type Ia Supernovae

Max utilizes large datasets of eclipsing binaries (EBs) to understand the formation, environments, and evolution of massive stars and binaries. In particular, Max measures the statistical distributions of binary star properties to test binary formation models and to provide initial conditions for binary population synthesis studies. He also incorporates EB populations to investigate tidal evolution, binary mass transfer and accretion processes, pre-main-sequence evolution, triple stars, feedback and dust content in young stellar nurseries, and the progenitors of Type Ia supernovae and X-ray binaries.

Burcin Mutlu-Pakdil

Ph.D. , 2017, University of Minnesota, Twin Cities
https://www.burcinmutlupakdil.net/ Areas of Interest: Structure, Morphology, and Dynamics of Galaxies; Galaxy Evolution; Black Hole-Galaxy Co-evolution

Burcin's research interests encompass both theoretical and observational aspects of extragalactic astronomy. She studies the structure and dynamics of galaxies, and examines what these can tell us about the galaxy formation process. Her recent research in galaxy structure has led to a discovery of an extremely rare galaxy. This work has provided a first description of a double ringed elliptical galaxy. Currently, she works on the general topics of nearby galaxies, resolved stellar populations and near-field cosmology.

Paola Pinilla

NASA Hubble Fellow
Ph.D , 2013, University of Heidelberg
http://www.u.arizona.edu/~pinilla/

Paola's research focuses on understanding the first steps of planet formation by developing numerical simulations of gas and dust evolution in disks around young stars. She likes to directly compare the results from these theoretical models to observations, and has had the great opportunity to work also with data from different telescopes, such as ALMA, VLT/SPHERE, and PdBl. She did her bachelor and master studies in Colombia (Universidad de los Andes) and obtained her Ph.D. from the University of Heidelberg, Germany. Afterwards, she was a post-doc for three years at Leiden Observatory in the Netherlands.

Benjamin Rackham

PhD, 2018, University of Arizona
Areas of Interest: Exoplanets, Planetary Atmospheres, Astrobiology

Ben studied the atmospheres of exoplanets via ground-based observations. He uses spectroscopic and photometric approaches to investigate molecular absorption and emission features of super-earths and hot jupiters, which constrain atmospheric models of these planets. These techniques can be applied to future projects characterizing the atmospheres of Earth-like planets in the habitable zones of nearby stars. Ben earned his PhD in Astronomy and Astrophysics from the University of Arizona in 2018, and joined Dr. Daniel Apai's EOS Team on characterizing extrasolar planets with special emphasis on small transiting exoplantes.

Everett Schlawin

Ph.D., 2015, Cornell University
http://mips.as.arizona.edu/~schlawin/ Areas of Interest: Exoplanets, Atmospheres, Instrumentation

Everett is interested in what planets and their atmospheres are made of. He studies planet composition by observing transiting planets - planets that cross in front and behind their host stars. Everett is a member of the James Webb Space Telescope NIRCam team, led by Marcia Rieke. The unprecedented Webb telescope will enable giant leaps in our understanding of planet composition. Personal Website: http://mips.as.arizona.edu/~schlawin/

Irene Shivaei

NASA Hubble Fellow
Ph.D., 2017, UC Riverside

Irene Shivaei earned her Ph.D. at UC Riverside, advised by Professor Naveen Reddy. Her work is part of the MOSDEF project to use the multi-object near-infrared spectrograph MOSFIRE on the Keck I Telescope to study the high redshift (z~2) Universe. She has focused on determining accurate star formation rates, comparing estimates from H alpha and H beta with those from infrared measurements, and on the behavior of the mid-infrared aromatic bands with metallicity. She will expand this work with JWST, using MIRI GTO data in the Hubble Ultra-Deep Field region. Irene is also involved in outreach, for example as a co-founder of the StarYab astrophysical literature website with weekly discussions of recent astronomy research results in Persian.

Jordan Stone

NASA Hubble Fellow
Ph.D., 2015, University of Arizona
http://zelda.as.arizona.edu/~jstone Areas of Interest: Star and Planet Formation, Brown Dwarf and Exoplanetary Atmospheres, High-Contrast Imaging, Interferometry

I've been working to understand the physical nature of protoplanetary disks around young stars to better understand how the late evolution of proto-star--disk--proto-planet systems produce the variety of planetary systems observed.

Carlos J. Vargas

Ph.D., 2018, New Mexico State University
Areas of Interest: Galaxy Evolution, Star Formation, ISM/CGM, Disk-halo interface, Radio/sub-mm Astronomy

Carlos studies the relationship between star formation and the diffuse inner halos of spiral galaxies. He is particularly interested in the mechanisms behind the prevalence and support of matter residing outside of star-forming galaxy disks. He has led studies analyzing the cycling of gas and cosmic rays between galaxy disks and halos, as well as a study of high redshift Lyman-alpha emission. Carlos joined Steward Observatory in September of 2018 to work with Dr. Erika Hamden.

Ryan Westernacher-Schneider

Ph.D., 2018, University of Guelph
Areas of Interest: Turbulence, core-collapse supernovae, Relativistic Astrophysics, Gravitational Waves, Numerical Relativity, Fluid-Gravity Duality

Ryan Westernacher-Schneider will be joining Steward Observatory on September 1, 2018 to work with Prof. Vasilis Paschalidis. Ryan grew up in Toronto, Canada. He was an undergraduate at the University of Toronto, and did his graduate studies at the University of Guelph and the Perimeter Institute for Theoretical Physics with Luis Lehner. He has worked on the statistical theory of relativistic turbulence using analytic techniques and numerical simulations, and applied it to turbulent black holes via the fluid-gravity duality. He has ongoing work on tidal disruption events, as well as gravitational wave asteroseismology of core-collapse supernovae and associated multimessenger detection strategies.

Christina Williams

NSF Fellow
PhD., 2014, University of Massachusetts Amherst
http://mips.as.arizona.edu/~cwilliams/ Areas of Interest: Galaxy Formation and Evolution, Stellar Feedback, galactic outflows

Jinyi Yang

Ph. D. , 2017, Peking University
Areas of Interest: High-z Universe & Reionzation, High-z Quasar/AGN evolution, Super massive black hole growth, Quasar surveys at multi-redshift ranges, and Absorption Systems in quasar spectra

Dr. Yang joined Steward Observatory in November 2017. Jinyi's research focuses on quasar evolution and quasar surveys at high redshift. During her thesis, she measured the quasar luminosity function at z ~ 5 and studied the quasar evolution model at high redshift. She carried out a survey of quasars at the redshift gap (z~5.5) of quasar color selection using a new selection pipeline. She is working on the study of multi-wavelength properties of quasars and the co-evolution between SMBHs and quasar host galaxies at z>~5, and is also involved in searching and follow-up works of quasars at z>~6. Additionally, she is interested in absorption systems towards quasar spectra, which can trace the redshift evolution of neutral hydrogen and metals in the intergalactic and galactic scales. At Steward Observatory, she will continue the research on high redshift quasars and the cosmic reionization.

Huanian Zhang

Ph.D., 2016, University of Arizona
Areas of Interest: Galaxy structure and gas halos, low surface brightness galaxies.

Huanian received his Ph.D in theoretical particle physics, specifically in new physics beyond Standard Model. Huanian's research mainly focuses on ionized gas halos of low redshift galaxies. Using a sample of nearly half a million foreground galaxies, probed by over 7.4 million low-background spectra from the Sloan Digital Sky Survey Data Release 12, Huanian traces Halpha emission to about 100 kpc galactocentric radius. Huanian has also presented the first evidence for a widely distributed, neutral, excited hydrogen component of the Milky Way Galaxy that is observed only as slight absorption in the combined spectra of millions of galaxy spectra. Huanian's research interests also include mapping the CGM of individual galaxies, searching for globular clusters within the local volume, and building the all-sky catalog of Ultra Diffuse Galaxies.