Einstein Fellows

Laura Blecha

University of Maryland, College Park

Seeking the Origin of Single and Double Active Black Holes

Laura will receive her PhD from Harvard University in May 2012. Prior to this, she completed her bachelors degree at Northwestern University and an MPhil degree at Cambridge University in England. She is originally from Manhattan, KS.

Laura's research concerns the behavior of supermassive black holes and their relationship with their host galaxies, particularly during galaxy mergers. Active black holes play a key role in the evolution of galaxies, and when triggered by mergers, they may be observed as dual or recoiling AGN. These phenomena provide crucial information about the growth history of supermassive black holes as well as their merger rate; such events could be detected with pulsar timing arrays or future gravitational-wave observatories.

As an Einstein Fellow, Laura will use hydrodynamic simulations to model the electromagnetic signatures of black hole pairs during galaxy mergers, motivated by recent discoveries of candidate AGN pairs at an unprecedented rate. A better theoretical understanding of their signatures will aid the design of future surveys and follow-up observations, as well as constraining the timescales for black hole inspiral, merger, and recoil. She also plans to study the various processes in addition to mergers that can trigger AGN activity, especially in the low-luminosity regime where the dominant fueling mechanisms are not well constrained.

Julie Hlavacek-Larrando

Stanford University

Unraveling AGN Feedback: from Isolated Elliptical Galaxies to Massive Clusters of Galaxies

Julie Hlavacek-Larrondo was raised in Montreal, Canada, and is originally half-Chilean, half-Czech. In 2007, she completed a Bachelor’s degree in physics at the University of Montreal, where she was introduced to research through two summer internships, enabling her to consolidate her passion for astrophysics. Julie then pursued a Master’s degree in astrophysics focusing on the kinematical analysis of three Sculptor Group galaxies.

In 2009, she moved to the UK to undertake a Ph. D at the University of Cambridge. During her doctorate, Julie has studied AGN feedback in the most luminous, and therefore massive, clusters of galaxies. Massive clusters of galaxies with strong cool cores require extreme mechanical feedback from their central AGN to offset cooling of the intracluster medium. These are the objects where you expect to find the most powerful examples of AGN-driven outflows. Julie’s work focused on studying the outflow properties in these systems, as well as the radiative properties of the central AGN, thus providing insight into the black holes that power the outflows. Her work involved using both Chandra X-ray observations, as well as radio observations from the Jansky VLA and GMRT. Julie will receive her Ph. D in the summer of 2012.

As an Einstein fellow at Stanford University, Julie will extend her work to the overall population of elliptical galaxies, from isolated ellipticals to those embedded at the centers of massive clusters of galaxies. Her aim is to provide a detailed view on the role AGN outflows play in the formation and evolution of elliptical galaxies, from heating to metal entrainment, as well as black hole growth.

Ann-Marie Madigan

University of California at Berkeley

The Dynamics of Stars in Disks around Massive Black Holes

Originally from Dublin, Ann-Marie earned her B.Sc in Physics and Astronomy at the National University of Ireland, Galway. She received both her M.Sc. and her Ph.D. in Astronomy (February 2012) from Leiden Observatory in the Netherlands.

Ann-Marie is interested in the long-term dynamics of stars orbiting massive black holes in the centers of galaxies. Such dynamics are responsible for illuminating massive black holes both through highly-energetic electromagnetic phenomena (e.g., tidal disruptions of stars) and gravitational-wave emission (in-spirals of compact stellar remnants). As an Einstein Fellow, she will study the formation and dynamics of stars in coherently-eccentric disks near massive black holes. She aims to address questions such as how they affect the (possibly counter-rotating) nuclear star cluster in which the massive black hole is embedded, and how disks from repeated formation events interact with one another.

Smadar Naoz

Harvard University

Black Holes through Cosmic Times

Smadar Naoz is originally from Jerusalem Israel. Her passion for science and astrophysics started at the age of five, ignited by a family tradition of watching Star Trek (the original series). Smadar received her B.Sc. and M.Sc. in the Hebrew University of Jerusalem, and then her Ph.D in Tel Aviv University. In January 2010 she joined Northwestern CIERA as an IAU Gruber fellow postdoc and later moved to Harvard university as an ITC fellow. As an Einstein fellow Smadar is planning to study the evolution and dynamical properties of both massive and stellar mass Black Holes through cosmic times.

The presence of massive black holes at the centers of galaxies influences the star formation and the total radiation released from these galaxies. Galaxies with central BHs go through an active galactic nucleus phase in which they release high-energy radiation as feedback into the intergalactic medium, while galaxies without central BHs tend to release softer radiation. Thus, it seems that BHs evolution is directly linked to the evolution of galaxies and halos.

Furthermore, it seems that major galaxy mergers should inevitably result in the formation of binaries and even triple black hole system. Smadar is planning to study the evolution and dynamical properties of BHs seeds from the first stars to present day. Some of the dynamical properties which are expected for multi-system massive black holes can be scaled down to stellar black holes. This is supported by observations which suggest that many stellar binaries with two compact objects are likely produced through triple evolution. Smadar plans to study triple systems and their crucial role in forming compact objects.

Joey Neilsen

Boston University

Heart of Darkness: High-Resolution X-ray Spectra of Outflows, ADAFs, and Sgr A*

Joey grew up in St. Louis, Missouri and received bachelor's degrees in Physics and Math from Kenyon College in Gambier, OH. He was a graduate student with Julia Lee at Harvard University, where he defended his PhD in April 2011. He is currently a Postdoctoral Associate in the Chandra HETG group at MIT.

Joey's research focuses on understanding the processes that control the mass and energy budget of accreting black holes. How is it that stellar-mass black holes in X-ray binaries can outshine Sgr A*, the supermassive black hole at the center of our Galaxy, by a factor of 1 million? We know that black hole systems can launch powerful relativistic jets and massive, ionized winds, but what determines how much of the accreting mass-energy is channeled into these jets and winds, how much is converted to radiation, and how much is swallowed by the black hole?

As an Einstein Fellow, Joey will search for answers to these questions with parallel X-ray, radio, and infrared studies of X-ray binaries and Sgr A*. He will use high-resolution X-ray spectra from Chandra to probe the links between inflowing gas and outflowing winds, and radio/infrared observations to track the behavior of relativistic jets. By synthesizing his studies of X-ray binaries and supermassive black holes, Joey will search for the physics that connects black holes of all masses to their surroundings.

Chris Nixon

University of Colorado, Boulder

Supermassive Black Holes: Rapid Accretion and Efficient Merging

Chris grew up in Durham, England and received his Masters degree in Astrophysics from the University of Cambridge. He then joined the Theoretical Astrophysics Group at the University of Leicester where he will receive his PhD in the summer of 2012.

Chris' current research is based on accretion disc theory, and has focused on the formation and propagation of disc warps and how they can be used to explain various astrophysical phenomena. At the University of Colorado he will consider the effect of chaotic accretion events on to supermassive black holes (SMBH) and SMBH binaries. His aim is to build up a coherent picture of how galaxies and their central black holes grow together.

Christian Reisswig

California Institute of Technology

Long Gamma-Ray Burst Central Engines and Multi-Messenger Astrophysics

I grew up in a village between Hannover and Braunschweig, Germany. Following my undergraduate studies at the Leibniz University Hannover, I joined the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Potsdam/Golm to work first on my Diploma project, and subsequently on my PhD research, which I completed in 2010.

During that time, my main focus was on vacuum numerical relativity. I developed and used parallel simulation codes to study the general relativistic dynamics of binary-black hole mergers, their gravitational wave emission, and the properties of the merger remnant.

When I arrived at Caltech as a postdoc in 2010, I became interested in the physics of black hole formation and central engines of long gamma-ray bursts, and how black hole formation can be modelled and simulated on large parallel computers. Long gamma-ray bursts are most likely produced by massive stars which, at the end of their nuclear burning life, are sufficiently massive to undergo core collapse and form a black hole that is surrounded by an accretion disk. Eventually, magneto-hydrodynamic coupling and/or neutrino/anti-neutrino annihilation can power collimated jet outflows. The exact nature and mode of operation of the central engine are still uncertain. Large-scale massively-parallel multiphysics simulations will be necessary for gaining theoretical insight into the long gamma-ray burst central engine.

As an Einstein Fellow, I intend to enhance current simulation codes with the aim of being able to self-consistently simulate stellar collapse and core bounce, proto-neutron star formation, black hole formation, hyperaccretion, accretion disk formation, and ultimately, the onset of collimated jet outflows. This requires general-relativistic magneto-hydrodynamic simulations in full 3D, including a proper treatment of neutrino radiation transport.

Fabian Schmidt

Princeton University

Testing Gravity with Large-Scale Structure

Fabian is a (mostly) theoretical cosmologist and received his PhD in Astronomy & Astrophysics at the University of Chicago in 2009. While there, he also worked on the Pierre Auger Observatory of ultra-high energy cosmic rays. He is currently a Moore Fellow with the Theoretical Astrophysics (TAPIR) group at Caltech.

Fabian's current research focuses on using large-scale structure to probe fundamental questions in cosmology, such as the behavior of gravity on large scales and the origin of the initial perturbations of the Universe. Much of his research involves theoretical work and simulations, but he also works closely with more observationally oriented colleagues. He is also interested in weak gravitational lensing, and has recently completed a measurement of magnification through a new method that uses galaxy sizes and fluxes.

Leo Stein

Cornell University

Probes of Corrections to General Relativity

Leo is interested in studying strong gravity from an astrophysical standpoint, a regime which has yet to be experimentally probed. Gravity is quite weak in terrestrial labs and the solar system, but the universe kindly gives us several astrophysical laboratories where gravity is strong. Two such natural laboratories are compact-object binaries and the very early universe. Learning something about strong-field gravity requires "clean" systems which we have a theoretical handle on (for example if we can say that the details of accretion physics are unimportant).

As an Einstein Fellow at Cornell, Leo will investigate comparable mass-ratio compact object binaries with an eye to placing constraints on corrections to general relativity (GR). Data from presently known pulsar binaries can be used to constrain deviations from GR using statistical methods (Markov chain Monte Carlo). In the future, the direct detection of gravitational waves from the same systems will provide even better constraints. Leo will also work on generating accurate gravitational waveforms from extreme mass-ratio inspirals (EMRIs). EMRIs can potentially serve as a sensitive probe of gravitational physics, but only if we are confident that our numerical models are sufficiently accurate—that our numerical methods resolve the physics, and that all the relevant effects (such as spin-curvature coupling and the gravitational self-force) have been included.

Leo will receive his Ph.D. from MIT in the summer of 2012. Before coming to MIT, he studied physics at Caltech. Leo was born in Ukraine, and his family immigrated to the US when he was 5. He grew up in a suburb of Rochester, N.Y.

Meng Su

Massachusetts Institute of Technology

The Nature of the Fermi Bubble: Implications for Galactic Cosmic Rays and the Growth of the Supermassive Black Hole in the Milky Way

Meng Su is completing his Ph.D. in astrophysics at Harvard University, working with thesis advisor Prof. Douglas Finkbeiner on Galactic diffuse gamma-ray emission. He has been working with Prof. John Kovac on the BICEP experiment at the South Pole, and Prof. Matias Zaldarriaga on various topics in theoretical cosmology. Before going to Harvard, Su received his undergraduate degree in physics from Peking University (Beijing University) in 2007. He is originally from Taiyuan in China, a city close to the Yellow River with more than a 2500 year history.

Meng Su is interested broadly in cosmology and high energy astrophysics. He uses gamma-ray, X-ray and microwave observations to study the diffuse emission from our Milky Way, the cosmic ray acceleration and propagation, and the supermassive black hole in the Galaxy. Along with Doug Finkbeiner and Tracy Slatyer, Su has discovered a giant gamma-ray bubble structure in the Milky Way (named, "Fermi Bubble"), which has been selected as one of the top ten physics-related news in 2011 by the American Physical Society. Su has also been studying varies topics in cosmology, including detection of B-mode polarization of the Cosmic Microwave Background (CMB), primordial non-Gaussianity of CMB, gravitational lensing of CMB, cosmic reionization, possible Lorentz violation in the early Universe, and constraining properties of dark energy using various cosmological probes.

Reinout van Weeren

Smithsonian Astrophysical Observatory

Galaxy Clusters: Unraveling the Mystery of the Largest Particle Accelerators in our Universe

Galaxy clusters are the largest gravitationally bound structures in our Universe. They are unique laboratories to study some of the most fundamental questions in astrophysics, related to the physics of particle acceleration and shocks, the growth of large-scale structure, and cosmology. In addition, galaxy clusters are key probes to study the mysterious dark matter that makes up most of the mass in the Universe. Galaxy clusters form through a sequence of mergers of smaller sub-clusters. During merger events, large shock waves are created. In such shocks, the diffusive shock acceleration mechanism should accelerate particles to highly relativistic energies. In the presence of a magnetic field, these particles would form large regions emitting synchrotron radiation at radio wavelengths. It has been suggested that such synchrotron emitting regions can be identified with elongated Mpc-sized radio sources, located mostly in the outskirts of massive merging galaxy clusters.

Reinout van Weeren obtained his PhD from Leiden University in 2011 where he worked on radio observations of merging galaxy clusters. During his PhD research, he discovered several spectacular merging galaxy clusters that provided unique evidence for particle acceleration in cluster merger shocks. In addition, he carried out hydrodynamical simulations of cluster mergers, with the aim of determining the merger parameters for specific clusters. During his Einstein Fellowship, he will combine the results at radio wavelengths with X-ray observations that probe the hot ionized gas which permeates the entire cluster's volume. Several of the newly discovered merging clusters will be imaged at high-resolution with NASA's Chandra X-ray Observatory to search for shocks in the X-ray emitting gas. XMM-Newton observations will be used to map the fainter outskirts of the clusters. Furthermore, observations with the new LOFAR radio telescope and Expanded Very Large Array will be taken to create larger samples of merging clusters, map the radio emission in a largely unexplored frequency range and at unprecedented depth. This combined X-ray and radio approach is crucial to unravel the physics particle acceleration and the origin of magnetic fields in galaxy clusters.

Justin Vandenbroucke

SLAC National Accelerator Laboratory

Development of Innovative Methods for Gamma-ray Astronomy with the Fermi Gamma-ray Space Telescope

Justin Vandenbroucke developed a fascination with astro-particle physics during an undergraduate research project to explore a new method of detecting cosmic neutrinos, acoustically, in the Bahamas. Justin received his PhD from UC Berkeley in 2009 for work on the IceCube neutrino telescope at the South Pole. Since then he has been a Kavli Fellow at the Kavli Institute for Particle Astrophysics and Cosmology, a joint institute of Stanford University and SLAC National Accelerator Laboratory. At Stanford, Justin has developed readout electronics for the Cherenkov Telescope Array (CTA, a future ground-based telescope array for detecting gamma rays at the highest energies currently detectable) and analyzed gamma-ray and positron data from the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope.

Justin is interested in the interconnections between the smallest particles and the largest astrophysical objects in the universe. Cosmic neutrinos, gamma rays, and charged particles hold clues to some of the most important questions in contemporary physics and astrophysics, including the sources and acceleration mechanisms of cosmic rays and the nature of dark matter. With Fermi collaborators, he used the Fermi LAT along with the Earth’s magnetic field to measure charge-separated cosmic-ray electron and positron spectra in the 20 to 200 GeV range. The ratio of positron to electron spectra has implications for nearby astrophysical sources, such as pulsars, and for dark matter. In addition to analyzing astro-particle data, Justin particularly enjoys developing and operating new instrumentation. As an Einstein Fellow, Justin plans to continue analysis of Fermi gamma-ray data and electronics development for CTA.

Einstein Fellows

Akos Bogdan

Smithsonian Astrophysical Observatory

The Origin and Evolution of Hot Gas in Galaxies and Clusters of Galaxies

Akos Bogdan grew up in Pecs, Hungary. He became interested in astronomy during high school years. Akos was a graduate student at the Max Planck Institute for Astrophysics in Garching, Germany. He was awarded a PhD in 2010.

Akos is interested in various phenomena of high energy astrophysics. His PhD work mainly focused on the hot X-ray emitting gas from nearby galaxies and on the nature of progenitors of Type Ia Supernovae.

Currently, Akos is interested in the nature and evolution of hot X-ray emitting gas in galaxies and in clusters of galaxies. X-ray studies of the hot gas in galaxies and clusters of galaxies have extensive implications for our understanding of these systems. For example, the chemical enrichment of the interstellar medium and intracluster medium can be studied. The hot gas also reflects stellar feedback processes, and reveals foregoing activity of the central AGN. As an Einstein fellow, Akos will study various evolutionary states of hot gas in galaxies using the Chandra X-ray Observatory. His aim is to better understand Type Ia Supernova driven hot gas outflows and the chemical enrichment processes in low-mass elliptical galaxies, the fate of superwinds in starburst galaxies, and to explore the nature of multiphase gaseous X-ray emitting components in massive elliptical galaxies.

Sam Gralla

University of Maryland (College Park)

Gravitational Radiation from Extreme Mass-Ratio Inspiral

Born and raised in Los Angeles, CA, Sam is currently a (cold) graduate student at the University of Chicago. With supervisor Robert Wald, he has worked on a number of problems in the motion and gravitational-wave emission of astrophysical bodies. He will receive his Ph.D. in the summer of 2011.

The upcoming direct detection of gravitational radiation will open an entirely new window on the universe. One promising source of radiation is the inspiral of a compact object (neutron star or stellar black hole) into a supermassive black hole at the center of a galaxy. Determining the radiative signature of this system requires a detailed understanding of general relativistic particle motion--including radiation reaction effects--in the strongly curved region near a Kerr black hole. As Einstein Fellow Sam will investigate the use of a gauge convenient to the Kerr spacetime to perform self-consistent computations of the motion and gravitational radiation, as well as investigate how effects second-order in the mass ratio can be included in a wave-generation formalism.

Philip Hopkins

University of California - Berkeley

The Co-evolution of Galaxies and Supermassive Black Holes

Phil Hopkins is originally from Cleveland, Ohio. He has been interested in physics and astronomy as long as he can remember, but explored a number of other fields as well thanks to the encouragement of fantastic teachers in high school and university. After briefly flirting with a Classics major in college, returned to what he loved and majored in Astronomy. He received his Ph.D. in Astronomy at Harvard University in 2008, and since graduation has been a Miller Fellow in the Department of Astronomy at UC Berkeley.

Phil's research attempts to answer a diverse array of questions related to the evolution of galaxies and super-massive black holes. Using numerical simulations of the formation, evolution, and collisions between galaxies, he is interested in exploring the role of galaxy mergers in shaping not just the galaxies themselves, but also fueling and forming the massive black holes observed at the centers of nearly all massive galaxies today. He is particularly interested in the nature of "feedback" from those black holes -- whether the energy released in their growth can have an impact on the orders-of-magnitude larger scale of the galaxy as a whole. Ultimately, his work seeks to relate and understand the diverse populations of black holes, quasars, starburst galaxies, and both normal and "dead" (non star-forming) galaxies in a self-consistent, merger-driven cosmological scenario.

Matthew Kunz

Princeton University

From Plasma Microphysics to Global Dynamics in Clusters of Galaxies and Accretion Flows

Matthew Kunz is originally from Baltimore, MD. After receiving degrees in Astronomy-Physics and Music from the University of Virginia, he obtained his Ph.D. in Physics from the University of Illinois at Urbana-Champaign. In September of 2009, he joined the Rudolf Peierls Centre for Theoretical Physics at the University of Oxford as a Postdoctoral Research Associate.

Matthew's research focuses on the effects of cosmic magnetism on a wide variety of astrophysical systems and processes. He spent his undergraduate and graduate years investigating the interplay between magnetic fields, dust, chemistry, and nonideal magnetohydrodynamic processes in molecular clouds, protostellar cores, and protoplanetary disks. More recently he has shifted his focus to much hotter and more diffuse astrophysical plasmas. While an Einstein Fellow at Princeton University, he will study the influence of plasma microphysics on the large-scale transport properties of weakly-collsional astrophysical systems, such as the intracluster medium, protogalactic disks, and black hole accretion flows. The ultimate goal is to construct an analytical and numerical modelling framework for astrophysical multiscale plasma dynamics, with an aim towards answering the following basic questions: What prevents the intracluster medium from undergoing catastrophic cooling? What sets the seemingly universal temperature profiles of cool-core clusters? How is the turbulent energy in both the intracluster medium and black hole accretion flows thermalized? How are cluster and accretion disk magnetic fields generated?

Laura Lopez

Massachusetts Institute of Technology

Dissecting Supernova Remnants and HII Regions Observed with Chandra

Laura Lopez is completing her PhD in astronomy and astrophysics at the University of California Santa Cruz in June 2011. Before going to UCSC, Laura earned her bachelors degree in physics at the Massachusetts Institute of Technology in 2004. Laura is originally from Barrington, Illinois, a northwest suburb of Chicago.

Laura is interested in understanding both the beginning and ending of the stellar life cycle: how stars are born and how stars end their lives through supernova explosions. Regarding stellar death, Laura uses X-ray observations of supernova remnants to discern the physical properties of compact objects, supernova explosions, chemical mixing, and particle acceleration. Related to stellar birth, Laura analyzes imaging and spectroscopy from across the electromagnetic spectrum (radio, mm, infrared, optical, UV, and X-ray) to assess how massive stars influence their surrounding gas and dust.

Amy Reines

National Radio Astronomy Observatory

Probing the Early Evolution of Galaxies and Massive Black Holes with Nearby Star-Forming Dwarfs

In the earlier universe, the seeds of supermassive black holes are believed to have formed in the progenitors of today's massive galaxies. However, the birth and growth of these high-redshift black holes is poorly constrained by observations. Amy and her collaborators have recently identified a million-solar mass black hole in a nearby, vigorously star-forming, bulgeless dwarf galaxy called Henize 2-10. This serendipitous discovery offers the first opportunity to study a growing black hole in a nearby galaxy much like those in the earlier universe, and opens up an entirely new class of host galaxies in which to search for local analogues of primordial black hole growth. Moreover, this finding has important implications for our understanding of the evolution of galaxies and their central black holes. In particular, the lack of a discernible bulge in Henize 2-10 indicates that black hole growth can precede the build-up of galaxy spheroids, which has been a long-standing debate in the community.

During her Einstein Fellowship, Amy will search for other examples of massive black holes in star-forming dwarf galaxies to begin to characterize them as a population and help constrain theoretical models for the formation of the first high-redshift black holes. Amy will use X-ray observations from the Chandra X-ray Observatory and radio observations from the Expanded Very Large Array to hunt for the radiative signatures of black hole growth that can be hidden at optical wavelengths by intense star formation.

Amy will receive her Ph.D. in August 2011 from the University of Virginia, where she was a NASA Earth and Space Science Fellow.

Rubens Reis

University of Michigan

The Nature and Evolution of Accretion Flows:
Coronal Properties in X-ray Binaries and Active Galactic Nuclei

Rubens was born in Sao Paulo, Brazil. At the age of 10 he moved to London, England where he undertook his secondary education. He is currently in the final year of his Ph.D at the University of Cambridge, where he works in the field of X-ray astronomy, specifically exploring the properties of accretion disks surrounding stellar-mass black hole binaries, neutron stars and supermassive black holes in the centre of active galaxies.

His research makes use of the fact that most of the radiation from accreting objects is released within the innermost regions of the accretion disk. In the case of stellar mass black holes the radiation is predominately emitted in the X-ray band, thus allowing the underlying physics of the accretion process to be successfully studied using high quality X-ray spectra.

During his Einstein Fellowship, Rubens will build upon his previous research whilst at the same time exploring new avenues from which we can learn about the physics of these powerful objects. He will systematically explore the properties of the coronal region in a wide range of objects, specifically addressing questions on the role of the corona in state transitions and its relationship to the evolution of the geometry of the accretion flow in X-ray binaries and in the process of jet formation in both AGN and Galactic microquasars.

Ken Shen

Lawrence Berkeley National Laboratory

Theoretical Investigations of Type Ia Supernova Progenitors

Ken Shen received his Ph.D. in physics from UC Santa Barbara in 2010. Since his graduation, he has been a postdoc in the Department of Astronomy at UC Berkeley. He grew up near San Francisco, CA. His love of physics arose in middle school and was encouraged by great teachers throughout high school and university, but it was not until his graduate studies that his interest in astrophysics and, in particular, accreting white dwarfs in interacting binaries developed.

White dwarfs are the endpoints of stellar evolution for the majority of stars. They have ceased their thermonuclear burning and are held up by electron degeneracy pressure. Many of these white dwarfs exist in binary systems, orbited by a companion star. If the two objects come close enough, mass can be transferred onto the white dwarf's surface, where thermonuclear processes can be rejuvenated by this fresh accretion of nuclear fuel.

Ken's Einstein research will focus on binaries consisting of two white dwarfs, in which the mass transfer from one white dwarf to the other and the subsequent nuclear combustion have been speculated to give rise to Type Ia supernovae. While thousands of Type Ia supernovae have been observed and used empirically in cosmological studies, the basic nature of their progenitor systems is still debated. In light of mounting evidence casting doubt on the standard progenitor scenario involving a single white dwarf, Ken will examine the theoretical evolution of double white dwarf binaries from the onset of mass transfer to the possible ignition of violent thermonuclear burning in order to ascertain their potential as Type Ia supernova progenitors.

Jennifer Siegal-Gaskins

California Institute of Technology

Constraining Dark Matter and Astrophysical Source Classes with Multi-wavelength Cross-correlation

Jennifer received her Ph.D. from the University of Chicago in 2008. Since then she has been a Postdoctoral Fellow at the Ohio State University's Center for Cosmology and Astro-Particle Physics. Jennifer grew up in Frederick, Maryland.

As an Einstein Fellow, Jennifer plans to develop new multi-wavelength techniques to identify a dark matter signal in diffuse emission. The precise nature of dark matter remains one of the outstanding questions at the intersection of particle physics, astrophysics, and cosmology today.

The currently-operating Fermi Gamma-ray Space Telescope has the exciting potential to indirectly detect this elusive component of the universe by observing gamma rays produced by the annihilation or decay of dark matter particles in our Galaxy and throughout the universe. Jennifer's research will focus on using cross-correlation analysis of Fermi gamma-ray data and Planck microwave data to understand the origin of the measured diffuse backgrounds and possibly uncover a dark matter signal. Interestingly, recent results suggest that only ~15% of the diffuse background at gamma-ray energies is composed of emission from members of astrophysical source classes already detected by Fermi, leaving the origin of the majority of the diffuse background a mystery.

Lorenzo Sironi

Harvard University

Nonthermal Particle Acceleration in Relativistic Astrophysical Shocks

Lorenzo will receive his Ph.D. from the Department of Astrophysical Sciences at Princeton University in August 2011. He grew up in a rural village near Milan (Italy), but he moved to Pisa (Italy) for his undergraduate studies in Physics. There, he became fascinated with the richness of physical processes at work in astronomical sources, especially in the most powerful and relativistic objects, like Pulsar Wind Nebulae, AGN jets and Gamma-Ray Bursts.

In his research, he investigates the origin of nonthermal emission from such sources. It is still a mystery how these objects can accelerate particles up to the highly nonthermal energies required to explain the observed spectra, that typically extend from the radio up to the gamma-ray band.

During his Einstein Fellowship, he will address the problem of particle acceleration in relativistic shocks, compressions created where a relativistic flow collides with the surrounding medium. For the first time, recent computational advances allow to study this age-old problem from first principles. He will employ a self-consistent plasma simulation code that he co-developed at Princeton to study the micro-physics and efficiency of shock acceleration. His primary focus will be on the termination shock of Pulsar Wind Nebulae and on the mildly relativistic internal shocks of AGN jets and Gamma-Ray Bursts. By systematically exploring the regimes of shock parameters where particle acceleration can occur, he will be able to place important constraints on the sources of nonthermal radiation. This will help, in concert with dedicated high-energy experiments (Chandra, Fermi, and TeV telescopes), to unveil the nature of astrophysical nonthermal sources.

Einstein Fellows

Simona Giacintucci

University of Maryland

Low-frequency Radio and X-ray Study of the Life Cycles of Relativistic Matter in Galaxy Clusters

Boaz Katz

Institute for Advanced Studies

CR origin, SN shock break-outs

Matthew Kerr

Stanford University

A Powerful Multiwavelength Probe for Pulsar Magnetospheres

Matthew Kistler

Lawrence Berkeley Laboratory

The Origins and Evolution of Ultra-Relativistic Electrons in the Milky Way

Emily Levesque

University of Colorado

Probing Gamma-Ray Burst Host Galaxies out to z ~ 2

Emily grew up in Taunton, Massachusetts, and received her S.B. in physics from MIT in 2006. She was a Ford Fellow at the University of Hawaii, where she received her PhD in July of 2010. She is currently an Einstein Fellow at the University of Colorado at Boulder.

Emily's primary research interests focus on the progenitor environments of core-collapse supernovae and gamma-ray bursts (GRBs), and the impact of environmental properties on the post-main-sequence evolution of massive stars. Her recent work on core-collapse GRB host galaxies has revealed a robust but puzzling correlation between these events and low-metallicity host galaxies, emphasizing the as-yet-unclear role that metallicity plays in the evolution of GRB progenitors. She is currently interested in further probing these events' host environments, utilizing multi-wavelength diagnostics developed using new stellar population synthesis and photoionization models and the powerful capabilities of the Cosmic Origins Spectrograph on Hubble.

In addition, Emily is also currently studying the physical properties, evolution, and abundances of red supergiants (RSGs) in Local Group galaxies. Previous research with her collaborators has focused on developing effective temperature scales for these evolved massive stars in the Milky Way, Magellanic Clouds, and M31. Her current and future work will focus on extending these studies to lower-metallicity environments and constructing the first detailed abundance profile for RSGs, both of which will act as a crucial test of current stellar evolution and atmosphere models.

Xin Liu

Harvard University

Black Hole Growth and Its Link with Galaxy Evolution

Galaxies are thought to be assembled via hierarchical mergers. Since most massive galaxies are believed to harbor a massive black hole, mergers will lead to the formation of massive binary black holes. Despite the success of the merger scenario in explaining much of the observed AGN phenomenology and properties of the cores of elliptical galaxies, direct observational evidence for massive binary black holes remains surprisingly scarce. It has also been recognized that the evolution of galaxies is intimately linked to the growth of their central massive black holes. Understanding this link has become a central theme in the study of galaxy formation and evolution. Since massive black holes grow predominantly during violently accreting quasar phases, the direct quantification of star formation and stellar content in quasar host galaxies may offer a powerful probe to the problem, yet it is often hampered by the vast contrast ratio between quasar light and starlight. Obscured quasars provide a unique window to the luminous peak growth phase, for which direct spectroscopic host study is extremely challenging for unobscured quasars.

As an Einstein fellow, Xin Liu is working on the systematic identification and characterization of hierarchical mergers of massive black holes and the quantification of star formation and stellar content of luminous obscured quasars. Originally from Jilin, Xin received her BS in physics from Tsinghua University, Beijing. She received a PhD in Astrophysics from Princeton University in 2010, before starting her fellowship at Harvard University.

Tony Mroczkowski

Jet Propulsion Laboratory

Probing High-z Clusters through MUSTANG 9'' SZE Imaging and the Chandra X-ray Observatory

Tony Mroczkowski grew up in Houston, Texas. He went to university mostly in New York City at the Cooper Union for the Advancement of Science and Art, where he e arned a B.S. in engineering, and at Columbia University where he earned an Astro nomy Ph.D. in September, 2008. He performed his first postdoc at the University of Pennsylvania on instrumentation for BLAST-Pol, a submillimeter experiment wi th polarization capabilities designed to measure star formation in our own galax y, before starting the Einstein Fellowship in summer of 2010.

Galaxy clusters are the largest bound objects in the Universe, and can therefore be used as both astrophysical laboratories and to place constraints on the evol ution of large scale structure. Tony is interested in developing the next gener ation of tools for observing various aspects of the Sunyaev-Zel'dovich effect (S ZE) from galaxy clusters. In particular, he aims to image the SZE at high resol ution, where cluster astrophysics meets cluster cosmology. The SZE is proportio nal to the line of sight integral of electron pressure through a cluster, and ha s a redshift independent surface brightness. The SZE at high resolution therefo re probes properties complementary to those probed in Chandra X-ray observations .

His current work at U Penn is with the 90-GHz 9'' bolometer array MUSTANG, on the Green Bank Telescope (GBT). He also hopes to built a much more sensitive repla cement for MUSTANG that could reach background-limited performance (BLIP) and ma ke the GBT the most sensitive ground-based instrument for high-resolution studie s of the thermal gas in clusters.

Ryan O'Leary

University of California at Berkeley

Dynamics of Stars and Gas around Supermassive Black Hole Binaries

Dovi Poznanski

Lawrence Berkeley National Laboratory

Type II Supernovae: Cosmology and Demographics

Dovi Poznanski is currently a Postdoctoral fellow at Lawrence Berkeley National Laboratory in the Computational Research Division, having recently been awarded an Einstein Fellowship from NASA. He is a member of various supernova and transient groups such as the Palomar Transient Factory and the Lick Observatory Supernova Search. Poznanski completed his Physics bachelor's degree Magna Cum Laude at the Tel Aviv University in 2002, followed by a PhD in Physics and Astronomy awarded in 2007 on the subject of "Deep and Wide Supernova Surveys." He was a postdoctoral fellow at the Astronomy Department of UC Berkeley between 2007 and 2010, working with the groups of Profs. A. Filippenko, J. Bloom, and P. Nugent. He is still an active member of all three groups.

Poznanski's main research interests focus on the observation and study of supernovae of the different kinds, thermonuclear or core-collapse, nearby or far away, known or predicted. He works as well on their use as cosmological probes, and on harnessing of modern computational capabilities to extract knowledge in the nascent field of synoptic surveys.

Nicolas Yunes

Massachusetts Institute of Technology

Exploiting Gravitational Wave Observations: Modeling of Extreme-Mass Ratio Inspirals and Tests of Fundamental Physics

Born and raised in Buenos Aires, Argentina, Nico earned his Bachelors in Science from Washington University in Saint Louis in 2003 under the supervision of Cliff Will, and his PhD from Penn State University in 2008, under the supervision of Ben Owen.

Gravitational waves are the last untested prediction of Einstein's theory of General Relativity. A world-wide effort is currently underway to detect such undulations of spacetime. Their detection will reveal invaluable information about the sources that produced such waves and about the fundamental theory of gravity. As an Einstein fellow, Nico has investigated how gravitational waves emitted from compact object binary systems could be used to probe astrophysics and fundamental physics theory. On the astrophysics side, he has studied how a non-vacuum astrophysical environment (such as an accretion disk or the presence of other supermassive black hole perturbers) imprints itself on gravitational waves, allowing us to extract astrophysical information after detection. On the theory side, he has developed and studied a model-independent framework to test General Relativity once waves are detected. This framework could be used by current ground-based detectors to constrain deviations from General Relativity to exciting new levels.

Einstein Fellows

Tamara Bogdanovic

University of Maryland

Astrophysics of Supermassive Black Holes and Cool Core Clusters

Tamara Bogdanovic's research interests are in astrophysics of black holes. She studies observational signatures associated with single and binary supermassive black holes interacting with gas and stars in galactic nuclei as well as the effects that these interactions have on black holes. She also investigates the role that MHD plasma processes play in the transport of energy and momentum in intracluster medium in clusters of galaxies. While hydrodynamical simulations are one of her main research tools, she enjoys collaborating on observational projects as well, and sure can appreciate real observational data.

Tamara was born and grew up in Serbia where she received her B.Sc. in astrophysics from the University of Belgrade. In 2006 she received a PhD in astronomy from the Pennsylvania State University and moved to the University of Maryland to become an Astronomy Prize Theory Fellow. She is currently an Einstein Postdoctoral Fellow at the University of Maryland.

Rodgrigo Fernandez

Institute for Advanced Study

3D Core-Collapse Supernova Hydrodynamics and X-ray Emission from Compact Objects

Bence Kocsis

Harvard University

Electromagnetic and Gravitational Wave Signatures of Black Hole Mergers

Bret Lehmer

Johns Hopkins University

Towards an Understanding of the Star-Formation and Supermassive Black Hole Accretion History of the Universe Using Deep Extragalactic Surveys

Bret is originally from Iowa. He received undergraduate degrees in Physics and Astronomy from the University of Iowa in 2002 and completed his PhD in Astronomy and Astrophysics from Penn State University in 2007. From 2007 to 2009, he conducted research as a Science and Technology Facilities Council(STFC) fellow. In the fall of 2009 he moved to the Baltimore/Washington D.C. area where he now works as an Einstein Fellow at Johns Hopkins University and Goddard Space Flight Center.

His research uses X-ray observations from Chandra and multiwavelength data from several other facilities to study X-ray binaries and accreting supermassive black holes (SMBHs) in nearby and distant galaxy populations. He is primarily interested in understanding how characteristics of galaxies (including their star-formation activity, mass, and age) and their environments lead to the production of compact objects and the growth of SMBHs.

Matthew McQuinn

University of California at Berkeley

Studies of Dark Matter Substructure and Reionization

Matt grew up in Virginia and Texas, before moving to Stanford, CA, for his undergraduate education. Matt received his PhD in 2004 from Harvard and currently is a post-doctoral fellow at the University of California, Berkeley.

Matt specializes in the study of the stuff between galaxies (which constitutes the majority of the mass in the Universe). He studies the properties of this intergalactic matter and its evolution from the infant Universe up until today. He works on modeling how it was ionized, heated, and enriched with metals as well as on developing methods to measure its evolution. He is also interested in the nature of the first galaxies, the large-scale structure of the Universe, the properties of the dark matter, and radiative transfer algorithms.

Brian Metzger

Princeton University

The Observational Signature of Compact Object Mergers and Accretion-Induced Collapse.

Eran Ofek

Caltech

The Nature of Long-Duration Radio Transients

Eduardo Rozo

University of Chicago

Cosmology from the SDSS and DES Cluster Samples

Born in Bogota, Colombia, Eduardo earned his Ph.D. in physics at the University of Chicago. After graduation, he joined The Ohio State University as a postdoctoral fellow at the Center for Cosmological and Astro-Particly Physics (CCAPP), and is now an Einstein Fellow at the University of Chicago.

Eduardo's research focuses on addressing the problem of constraining cosmological models using optically selected galaxy clusters. Over the next several years, a wide range of deep and wide photometric surveys will be coming online, including DES, HSC, PanSTARRS, and LSST. The data from these surveys will allow us to identify hundreds of thousands of clusters, leading to some of the statistically powerful data sets of the coming decade. Eduardo's work addresses how to succesfully tap into this statistical power, and how these surveys can complement other large scale surveys such as those in the X-ray (e.g. eRosita) and SZ (e.g. SPT, ACT, and Planck). Eduardo's goal is to use these various data sets to map out the growth of large scale structure across cosmologically relevant time scales as a means to test whether our accelerating universe is driven by a new form of energy --- the so called dark energy --- or whether this accelerating phase is signaling a breakdown of general relativity on cosmological scales.

Kevin Schawinski

Yale University

The Co-Evolution of Galaxies and their Supermassive Black Holes

Kevin Schawinski grew up in Switzerland and Germany. He received his D.Phil from Oxford University and stayed on briefly as the Henry Skynner Fellow at Balliol College. He moved to Yale University in 2008 and started his Einstein Fellowship in 2009.

Kevin works on the role that black holes play in the formation and evolution of galaxies. What is the correlation between black hole growth and evolutionary phases of galaxies? Which galaxies feed their black holes? And are black hole accretion phases associated with, and perhaps causing a change in the evolutionary trajectory of galaxies? And what is the origin of supermassive black holes in the very early Universe?

Kevin uses stellar populations to reconstruct the star formation histories of galaxies to infer the sequence of events surrounding black hole accretion events. He also co-founded and continues to be heavily involved in Galaxy Zoo, a citizen science project involving over 400,000 members of the public in scientific research that has now branched out into fields as diverse as climate change and finding extrasolar planets.

Aurora Simionescu

Stanford University

Using the Thermal Structure in the ICM to Understand the Physics of Galaxy Clusters

Chandra Fellows

Name	PhD Institution	Host Institution
Edward Cackett	St. Andrews	Univ. of Michigan
Orly Gnat	Tel Aviv	Cal Tech
Prateek Sharma	Princeton	Berkeley
Ezequiel Treister	Chile	Hawaii
Norbert Werner	Utrecht	Stanford

Fermi Fellows

Name	PhD Institution	Host Institution
Nathaniel Butler	MIT	Berkeley
Uri Keshet	Inst. for Advanced Study	Harvard
Vasiliki Pavlidou	U. Chicago	Caltech

Chandra Fellows

Name	PhD Institution	Host Institution
John Fregeau	MIT	Northwestern (yr 1)
		KITP-UCSB (yrs 2 & 3)
Jonathan McKinney	U. Illinois	Stanford
Ian Parrish	Princeton	Berkeley
Jesper Rasmussen	U. Copenhagen	Carnegie Obs.
Jeremy Schnittman	MIT	Johns Hopkins

Chandra Fellows

Name	PhD Institution	Host Institution
Carlos Badenes	Univ. Politecnica Catalunya	Rutgers
		Princeton
Shane Davis	UC Santa Barbara	Inst. for Advanced Study
Jifeng Liu	Univ. of Michigan	CfA
Elena Rasia	Univ. Padova	Univ. of Michigan
Masahiro Tsujimoto	Kyoto University	Penn State

Chandra Fellows

Name	PhD Institution	Host Institution
Elena Gallo	Amsterdam	Santa Barbara
Jon Miller*	MIT	SAO
Jan-Uwe Ness	Hamburg	Arizona State
Elena Rossi	Cambridge	Colorado
David Sand	CalTech	U. Arizona

Chandra Fellows

Name	PhD Institution	Host Institution
Franz Bauer	Virginia	Columbia
Doron Chelouche	Tel-Aviv	Inst. for Advanced Study
Benjamin Maughan	Birmingham	SAO
David Pooley	MIT	Berkeley
Weiquin Zhang	Santa Cruz	Stanford

Chandra Fellows

Name	PhD Institution	Host Institution
Taotao Fang	MIT	Berkeley
Sebastian Heinz	Colorado	MIT
Peter Jonker	Amsterdam	SAO
Enrico Ramirez-Ruiz	Cambridge	Inst. for Advanced Study
Mateusz Ruszkowski	Cambridge	Colorado

Chandra Fellows

Name	Ph.D. Institution	Host Institution
Ann Hornschemeier	Penn State	Johns Hopkins
Julia Lee	Cambridge	MIT
Eric Pfahl	MIT	Harvard
Anatoly Spitkovsky	Berkeley	Berkeley
Licia Verde	Edinburgh	Princeton

Chandra Fellows

Name	Ph.D. Institution	Host Institution
Elizabeth Blanton	Columbia	U. Virginia
Li-Xin Li	Princeton	Harvard
Andisheh Mahdavi	Harvard	U. Hawaii
Erik Reese	U. Chicago	UC Berkeley
Masao Sako	Columbia	Cal Tech

Chandra Fellows

Name	Ph.D. Institution	Host Institution
Eric Agol	UC Santa Barbara	Cal Tech
Ming Feng Gu	Columbia	MIT
Jeremy Heyl	UC Santa Cruz	CfA
David Strickland	Birmingham, UK	Johns Hopkins
Jacco Vink	Utrecht	Columbia

Chandra Fellows

Name	Ph.D. Institution	Host Institution
Markus Boettcher	Bonn	Rice
Jimmy Irwin	Virginia	Univ. of Michigan
Kristen Menou	Paris	Princeton
Eliot Quataert	Harvard	Inst. for Advanced Study
Rudy Wijnands	Amsterdam	MIT
Amy Barger*	Cambridge, UK	*Fellow at Large

Chandra Fellows

Name	Ph.D. Institution	Host Institution
David Buote	MIT	UC Santa Cruz
Tiziana Di Matteo	Cambridge, UK	Harvard
Ann Esin	Harvard	CalTech
Joseph Mohr	Harvard	Chicago
Edward Moran	Columbia	UC Berkeley