A5015296815- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Mechanics and Biomechanics Studies
- Plant Water Relations and Carbon Dynamics
- Radio Astronomy Observations and Technology
- Black Holes and Theoretical Physics
- Radio Wave Propagation Studies
- Experimental and Theoretical Physics Studies
- Particle physics theoretical and experimental studies
- CCD and CMOS Imaging Sensors
- Methane Hydrates and Related Phenomena
- Remote Sensing in Agriculture
- Magnetic confinement fusion research
- Astro and Planetary Science
- Remote Sensing and LiDAR Applications
- Computational Physics and Python Applications
- Computer Graphics and Visualization Techniques
University of Chicago
2023-2024
Center for Astrophysics Harvard & Smithsonian
2022-2023
University of California, Santa Cruz
2017-2021
University of Copenhagen
2017-2021
Harvard University Press
2013
We study the properties of tidal disruption event (TDE) host galaxies in context a catalog ~500,000 from Sloan Digital Sky Survey. explore whether selection effects can account for overrepresentation TDEs E+A/post-starburst by creating matched galaxy samples. Accounting possible due to black hole (BH) mass, redshift completeness, strong AGN presence, bulge colors, and surface brightness reduce apparent E+A factor ~4 (from ~$\times$100-190 ~$\times$25-48), but cannot fully explain preference....
Time domain science has undergone a revolution over the past decade, with tens of thousands new supernovae (SNe) discovered each year. However, several observational domains, including SNe within days or hours explosion and faint, red transients, are just beginning to be explored. Here, we present Young Supernova Experiment (YSE), novel optical time-domain survey on Pan-STARRS telescopes. Our is designed obtain well-sampled $griz$ light curves for transient events up $z \approx 0.2$. This...
We present the Young Supernova Experiment Data Release 1 (YSE DR1), comprised of processed multi-color Pan-STARRS1 (PS1) griz and Zwicky Transient Facility (ZTF) gr photometry 1975 transients with host-galaxy associations, redshifts, spectroscopic/photometric classifications, additional data products from 2019 November 24 to 2021 December 20. YSE DR1 spans discoveries observations young fast-rising supernovae (SNe) that persist for over a year, redshift distribution reaching z~0.5. relative...
A bstract In the dark dimension scenario, which predicts an extra of micron scale, gravitons (KK modes) are a natural matter candidate. this paper, we study observable features model. particular, their decay to standard fields can distort CMB and impact other astrophysical signals. Using place bounds on parameters particular find that range in scenario is consistent with these constraints leads prediction mean mass today close few hundred keV effective size around 1–30 μm.
We present the first simulations of tidal disruption stars with realistic structures and compositions by massive black holes (BHs). build in stellar evolution code MESA simulate their 3D adaptive-mesh hydrodynamics FLASH, using an extended Helmholtz equation state tracking 49 elements. study a 1$M_\odot$ star 3$M_\odot$ at zero-age main sequence (ZAMS), middle-age, terminal-age (TAMS). The maximum BH mass for increases factor $\sim$2 from radius changes due to MS evolution; this is...
Stars grazing supermassive black holes (SMBHs) on bound orbits may survive tidal disruption, causing periodic flares. Inspired by the recent discovery of nuclear transient ASASSN-14ko, a promising candidate for repeating disruption event (TDE), we study deformation stars approaching SMBHs eccentric orbits. With both analytical and hydrodynamics methods, show overall star is similar to that in parabolic orbit provided eccentricity above critical value. This allows one make use existing...
Tidal disruption events (TDEs) provide a unique opportunity to probe the stellar populations around supermassive black holes (SMBHs). By combining light curve modeling with spectral line information and knowledge about in host galaxies, we are able constrain properties of disrupted star for three TDEs. The TDEs our sample have UV spectra, measurements N III C ratios enabled estimates nitrogen-to-carbon abundance these events. We show that measured nitrogen widths consistent originating from...
Tidal disruption events (TDEs) are among the brightest transients in optical, ultraviolet, and X-ray sky. These flares set into motion when a star is torn apart by tidal field of massive black hole, triggering chain which -- so far incompletely understood. However, process has been studied extensively for almost half century, unlike later stages TDE, our understanding itself reasonably well converged. In this Chapter, we review both analytical numerical models stellar disruption. Starting...
We study the properties of host galaxies Changing-Look Active Galactic Nuclei (CL AGNs) with aim understanding conditions responsible for triggering CL activity. find that AGN hosts primarily reside in so-called green valley is located between spiral-like star-forming and dead ellipticals, implying AGNs are activated during distinct periods quenching galaxy transformation processes. have low asymmetry indicators, suggesting secular evolutionary processes (the influence bars spirals, possibly...
Abstract We use a simple framework to calculate the time evolution of composition fallback material onto supermassive black hole arising from tidal disruption main-sequence stars. study stars with masses between 0.8 and 3.0 M ⊙ , at evolutionary stages zero-age main sequence terminal-age sequence, built using Modules for Experiments in Stellar Astrophysics code. show that most develop enhancements nitrogen ( 14 N) depletions carbon 12 C) oxygen 16 O) over their lifetimes, these features are...
We construct a menu of objects that can give rise to bright flares when disrupted by massive black holes (BHs), ranging from planets evolved stars. Through their tidal disruption, main sequence and stars effectively probe the existence otherwise quiescent supermassive BHs white dwarfs intermediate mass BHs. Many low-mass possess extended hydrogen envelopes, which allow for production prompt in disruptive encounters with moderately $10^5$ $10^7~M_\odot$--masses may constitute majority number....
A bstract There have been many attempts to construct de Sitter space-times in string theory. While arguably there some successes, this has proven challenging, leading the swampland conjecture: quantum theories of gravity do not admit stable or metastable space. Here we explain that, within controlled approximations, one lacks tools space Such approximations would require existence a set (arbitrarily) small parameters, subject severe constraints. But beyond also needs an understanding...
A binary neutron star merger has been observed in a multi-messenger detection of gravitational wave (GW) and electromagnetic (EM) radiation. Binary stars that merge within Hubble time, as well many other compact binaries, are expected to form via common envelope evolution. Yet five decades research on evolution have not yet resulted satisfactory understanding the multi-spatial multi-timescale for systems lead binaries. In this paper, we report first successful simulations ejection leading...
Abstract We present a start-to-end simulation aimed at studying the long-term fate of high-mass X-ray binaries and whether Thorne–Żytkow object (TŻO) might ultimately be assembled. analyze results from 3D hydrodynamical that models eventual LMC X-4, compact binary system, after primary fills its Roche lobe engulfs neutron star companion. discuss outcome this engulfment within standard paradigm TŻO formation. The post-merger angular momentum content stellar core is key ingredient, as even...
Abstract We study the properties of galaxies hosting mid-infrared outbursts in context a catalog 500,000 from Sloan Digital Sky Survey. find that nuclear obscuration, as inferred by surrounding dust mass, does not correlate with host galaxy type, stellar (e.g., total mass and mean age), or extinction estimated Balmer decrement. This implies obscuration may be able to explain any overrepresentation tidal disruption events particular galaxies. identify region parameter space contains all...
We present the multi-wavelength analysis of tidal disruption event (TDE) AT~2018hyz (ASASSN-18zj). From follow-up optical spectroscopy, we detect first unambiguous case resolved double-peaked Balmer emission in a TDE. The distinct line profile can be well-modelled by low eccentricity ($e\approx0.1$) accretion disk extending out to $\sim$100 $R_{p}$ and Gaussian component originating from non-disk clouds, though bipolar outflow origin cannot completely ruled out. Our indicates that...
Modern graphics processing units come with dedicated hardware to perform ray/triangle intersections and bounding volume hierarchy traversal. While the primary use case for this is photorealistic 3-D computer graphics, careful algorithm design scientists can also special-purpose accelerate general-purpose computations, such as point containment queries. This article explains principles behind these techniques their application vector field visualization of large simulation data using particle tracing.
We measure the color and stellar mass dependence of clustering in spectroscopic galaxies at $0.6 < z 0.65$ using data from Baryon Oscillation Spectroscopic Survey component Sloan Digital Sky Survey. greatly increase statistical precision our measurements by cross-correlation 66,657 to a sample 6.6 million fainter photometric galaxies. The amplitude $w(R)$ is measured as ratio mean excess number found within specified radius annulus around galaxy that random distribution. recover many...
Abstract We present the STARS library, a grid of tidal disruption event (TDE) simulations interpolated to provide mass fallback rate ( dM / dt ) black hole for main-sequence star any stellar mass, age, and impact parameter. use one-dimensional evolution code construct stars with accurate structures chemical abundances, then perform in three-dimensional adaptive-mesh hydrodynamics Helmholtz equation state, unprecedented resolution: from 131 524 cells across diameter star. The library rates is...
Tidal disruption events (TDEs) are among the brightest transients in optical, ultraviolet, and X-ray sky. These flares set into motion when a star is torn apart by tidal field of massive black hole, triggering chain which -- so far incompletely understood. However, process has been studied extensively for almost half century, unlike later stages TDE, our understanding itself reasonably well converged. In this Chapter, we review both analytical numerical models stellar disruption. Starting...