A5088598643- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Spacecraft and Cryogenic Technologies
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Cosmic Phenomena
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Education and Teacher Training
- Food Drying and Modeling
- Complex Systems and Time Series Analysis
- Black Holes and Theoretical Physics
- Phase Equilibria and Thermodynamics
- Greenhouse Technology and Climate Control
- Material Science and Thermodynamics
- Earth Systems and Cosmic Evolution
Northwestern University
2018-2023
Millennium Institute of Astrophysics
2022-2023
Adolfo Ibáñez University
2021-2023
Data Observatory Foundation
2023
Northern Arizona University
2023
Centre National d'Études Spatiales
2020-2021
Thales (France)
2020-2021
National University of Río Cuarto
2013-2020
Cornell University
2014-2019
University of Arizona
2018-2019
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
Accurate numerical solutions of the equations hydrodynamics play an ever more important role in many fields astrophysics. In this work, we reinvestigate accuracy moving-mesh code \textsc{Arepo} and show how its convergence order can be improved for general problems. particular, clarify that certain problems only reaches first-order original formulation. This rectified by simple modifications propose to time integration scheme spatial gradient estimates code, both improving code. We...
We review recent works on the dynamics of circumbinary accretion, including time variability, angular momentum transfer between disk and binary, secular evolution accreting binaries. These impact stellar binary formation/evolution, planet formation/migration, (super)massive black hole discuss inclined/warped disks connect with observations protoplanetary disks. A special kind accretion involves binaries embedded in big disks, which may contribute to mergers stellar-mass holes AGN Highlights...
Energetic flares are observed in the Galactic supermassive black hole Sagittarius A* from radio to X-ray wavelengths. On a few occasions, simultaneous have been detected IR and observations, but clear counterparts at longer wavelengths not seen. We present flare over several hours on 2006 July 17 with Chandra X-Ray Observatory, Keck II telescope, Caltech Submillimeter Array. All telescopes strong events, submillimeter peak is found occur nearly 100 minutes after peak. polarization data show...
The Lidov-Kozai (LK) mechanism plays an important role in the secular evolution of many hierarchical triple systems. standard LK consists large-amplitude oscillations eccentricity and inclination a binary subject to quadrupole potential from outer perturber. Recent work has shown that when octupole terms are included potential, inner can reach more extreme eccentricities as well undergo orientation flips. It is known pericenter precessions due short-range effects, such General Relativity...
We carry out numerical simulations of circumbinary discs, solving the viscous hydrodynamics equations on a polar grid covering an extended disc outside binary co-orbital region. use carefully controlled outer boundary conditions and long-term integrations to ensure that reaches quasi-steady state, in which time-averaged mass accretion rate onto binary, $\langle\dot{M}\rangle$, matches supply at disc. focus binaries with comparable masses wide range eccentricities ($e_\mathrm{B}$). For...
ABSTRACT We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is first set to tackle problem binary a finite-volume scheme on freely moving mesh, which allows for accurate measurements individual stars arbitrary eccentricity. While shows bursts with period <?CDATA $\sim 5$?> times P b , an predominantly modulated at 1{P}_{{\rm{b}}}$?> . For equal-mass binary, rates are quite similar each other, following same...
The discovery of transiting circumbinary planets by the Kepler mission suggests that can form efficiently around binary stars. None stellar binaries currently known to host has a period shorter than 7 d, despite large number eclipsing found in target list with periods few days. These compact are believed have evolved from wider orbits into their current configurations via so-called Lidov-Kozai migration mechanism, which gravitational perturbations distant tertiary companion induce...
Abstract We carry out 2D viscous hydrodynamical simulations of circumbinary accretion using the moving-mesh code AREPO. self-consistently compute flow over a wide range spatial scales, from disk (CBD) far central binary, through streamers, to disks around individual binary components, resolving down 2% separation. focus on equal-mass binaries with arbitrary eccentricities. evolve long (viscous) timescales until quasi-steady state is reached, in which mass supply rate at large distances...
Lidov–Kozai oscillations of planets in stellar binaries, combined with tidal dissipation, can lead to the formation hot Jupiters (HJs) or disruption planets. Recent population synthesis studies have found that fraction systems resulting HJs (|${\cal F}_{\rm HJ}$|) depends strongly on planet mass, host type and dissipation strength, while total migration |${\cal mig} ={\cal HJ}+{\cal dis}$| (including both HJ disruption) exhibits much weaker dependence. We present an analytical method for...
ABSTRACT We present a suite of high-resolution hydrodynamic simulations binaries immersed in circumbinary accretion discs (CBDs). For the first time, we investigate preferential rate as function both eccentricity eb and mass ratio qb densely sampled parameter space, finding that when compared with circular binaries, (i) ratios grow more efficiently on moderately eccentric orbits (0.0 ≲ 0.4), (ii) high eccentricities (eb ≳ 0.6) suppress growth. suggest this non-monotonic behaviour may produce...
ABSTRACT The presence of a planetary system can shield planetesimal disk from the secular gravitational perturbations due to distant outer massive objects (planets or stellar companions). As host star evolves off main sequence become white dwarf, these planets be engulfed during giant phase, triggering instabilities and leading tidal disruptions small rocky bodies. These disrupted bodies feed dwarfs with material possibly explain high-metallicity in their atmospheres. We illustrate how this...
The Jovian-sized object WD~1856~b transits a white dwarf (WD) in compact $1.4$-day orbit. Unlikely to have endured stellar evolution its current orbit, is thought migrated from much wider separations. Because the WD old, and member of well-characterized hierarchical multiple, well-known Kozai mechanism provides an effective migration channel for WD~1856~b. Moreover, lack tides star allows us directly connect semi-major axis pre-migration one, which we can infer initial conditions system. By...
We carry out 2D viscous hydrodynamics simulations of circumbinary disk (CBD) accretion using {\footnotesize AREPO}. resolve the flow from a large-scale CBD down to streamers and disks around individual binary components. Extending our recent studies \citep{mun19}, we consider circular binaries with various mass ratios ($0.1\leq q_{\rm{b}}\leq1$) study ``infinite'', steady-supply finite-sized, viscously spreading tori. For ``infinite'' disks, global steady state can be reached, variability...
We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single transit events in light curves generated from full frame images Transiting Exoplanet Survey Satellite (TESS). Follow-up radial velocity measurements additional used to determine periods confirm planetary nature candidates. The planets orbit slightly metal-rich late F- early G-type stars. find that TOI 4406b has a mass $M_P$= 0.30 $\pm$...
Abstract Warm Jupiters lay out an excellent laboratory for testing models of planet formation and migration. Their separation from the host star makes tidal reprocessing their orbits ineffective, which preserves orbital architectures that result planet-forming process. Among measurable properties, inclination with respect to stellar rotational axis, stands as a crucial diagnostic understanding migration mechanisms behind origin close-in planets. Observational limitations have made...
Abstract High-eccentricity tidal migration predicts the existence of highly eccentric proto hot Jupiters on “tidal circularization track,” meaning that they might eventually become Jupiters, but their migratory journey remains incomplete. Having experienced moderate amounts evolution orbital elements, Jupiter systems can be powerful test beds for underlying mechanisms eccentricity growth. Notably, may used discriminating between variants high-eccentricity migration, each predicting a...
In this study, we present high-resolution millimeter observations of the dust and gas disk T Tauri star AS 205 N its companion, S, obtained with Atacama Large Millimeter Array. The around N, for which infrared emission spectroscopy demonstrates significant deviations from Keplerian motion that has been interpreted as evidence a wind (Pontoppidan et al. 2011; Bast 2011), also displays in presented here. Detections near both S are 1.3 mm continuum, 12CO 2-1, 13CO 2-1 C18O 2-1. is extended up...
The formation and early evolution of circumstellar discs often occurs within dense, newborn stellar clusters. For the first time, we apply moving-mesh code AREPO, to in 3-D, focusing on disc-disc interactions that result from fly-bys. Although a small fraction stars are expected undergo close approaches, outcomes most violent encounters might leave an imprint host will influence both their orbits ability form planets. We construct well-behaved 3-D models self-gravitating discs, then create...
Abstract Recent simulations show that giant planets of about 1 M J migrate inward at a rate differs from the type II prediction. Here we higher masses, outward. Our result previous ones because our longer simulation times, lower viscosity, and boundary conditions allow disk to reach viscous steady state. We that, for on circular orbits, transition outward migration coincides with known eccentric disks occurs more massive than few Jupiters. In an disk, torque outer weakens due two effects:...
We report observations of dust continuum emission at 1.2 mm toward the star forming region NGC 6334 made with SEST SIMBA bolometer array. The cover an area $\sim 2$ square degrees approximately uniform noise. detected 181 clumps spanning almost three orders magnitude in mass (3\Msun$-6\times10^3$ \Msun) and sizes range 0.1--1.0 pc. find that clump function $dN/d\log M$ is well fit a power law exponent -0.6 (or equivalently $dN/dM \propto M^{-1.6}$). derived similar to those obtained from...
We report the first detections of circularly polarized emission at submillimeter wavelengths from compact radio source and supermassive black hole candidate Sgr A* a level 1.2\pm0.3% 1.3 mm wavelength (230 GHz) 1.6\pm0.3% 860 microns (345 with same handedness as observed lower frequencies (1.4-15 GHz). The observations, taken Submillimeter Array in multiple epochs, also show simultaneous linear polarization (LP) both about 6%. These properties differ sharply those longer than 1 cm...
Abstract Important clues to the formation and evolution of planetary systems can be inferred from stellar obliquity ψ . We study distribution obliquities using California- Kepler Survey TEPCat Catalog Rossiter–McLaughlin (RM) measurements, which we extract, respectively, 275 118 targets. infer a “best fit” in with single parameter κ Large values imply that is distributed narrowly around zero, while small approximate isotropy. Our findings are as follows. (1) The narrower than found by...
Numerous formulations of finite volume schemes for the Euler and Navier-Stokes equations exist, but in majority cases they have been developed structured stationary meshes. In many applications, more flexible mesh geometries that can dynamically adjust to problem at hand move with flow a (quasi) Lagrangian fashion would, however, be highly desirable, as this allow significant reduction advection errors an accurate realization curved moving boundary conditions. Here we describe novel...
General-purpose, moving-mesh schemes for hydrodynamics have opened the possibility of combining accuracy grid-based numerical methods with flexibility and automatic resolution adaptivity particle-based methods. Due to their supersonic nature, Keplerian accretion discs are in principle a very attractive system applying such freely moving mesh techniques. However, high degree symmetry simple disc models can be difficult capture accurately by these methods, due generation geometric grid noise...