Search Publications
CMU DeepLens: deep learning for automatic image-based galaxy-galaxy strong lens finding
Mandelbaum, Rachel; Li, Nan; Collett, Thomas E. +5 more
Galaxy-scale strong gravitational lensing can not only provide a valuable probe of the dark matter distribution of massive galaxies, but also provide valuable cosmological constraints, either by studying the population of strong lenses or by measuring time delays in lensed quasars. Due to the rarity of galaxy-scale strongly lensed systems, fast an…
Ghostly tributaries to the Milky Way: charting the halo's stellar streams with the Gaia DR2 catalogue
Malhan, Khyati; Ibata, Rodrigo A.; Martin, Nicolas F.
We present a panoramic map of the stellar streams of the Milky Way based upon astrometric and photometric measurements from the Gaia DR2 catalogue. In this first contribution, we concentrate on the halo at heliocentric distances beyond 5{ kpc}, and at Galactic latitudes |b| > 30°, using the STREAMFINDER algorithm to detect structures along plau…
Constraints on the ejecta of the GW170817 neutron star merger from its electromagnetic emission
Gal-Yam, Avishay; Waxman, Eli; Ofek, Eran O. +1 more
We present a simple analytic model that captures the key features of the emission of radiation from material ejected by the merger of neutron stars (NSs), and construct the multiband and bolometric luminosity light curves of the transient associated with GW170817, AT 2017gfo, using all available data. The ultraviolet to infrared (IR) emission is s…
The origin of ultra diffuse galaxies: stellar feedback and quenching
Hopkins, P. F.; Wetzel, A.; El-Badry, K. +5 more
We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies (UDGs). We show that outflows that dynamically heat galactic stars, together with a passively aging stellar population after imposed quenching, naturally reproduce the observed population of red UDGs, withou…
Using the full power of the cosmic microwave background to probe axion dark matter
Hložek, Renée; Grin, Daniel; Marsh, David J. E.
The cosmic microwave background (CMB) places stringent constraints on models of dark matter (DM), and on the initial conditions of the Universe. The full Planck data set is used to test the possibility that some fraction of the DM is composed of ultralight axions (ULAs). This represents the first use of CMB lensing to test the ULA model. We find n…
Estimating stellar birth radii and the time evolution of Milky Way's ISM metallicity gradient
Recio-Blanco, A.; de Laverny, P.; Hayden, M. +14 more
We present a semi-empirical, largely model-independent approach for estimating Galactic birth radii, rbirth, for Milky Way disc stars. The technique relies on the justifiable assumption that a negative radial metallicity gradient in the interstellar medium (ISM) existed for most of the disc lifetime. Stars are projected back to their bi…
The abundance, distribution, and physical nature of highly ionized oxygen O VI, O VII, and O VIII in IllustrisTNG
Torrey, Paul; Vogelsberger, Mark; Genel, Shy +8 more
We explore the abundance, spatial distribution, and physical properties of the O VI, O VII, and O VIII ions of oxygen in circumgalactic and intergalactic media (the CGM, IGM, and WHIM). We use the TNG100 and TNG300 large volume cosmological magnetohydrodynamical simulations. Modelling the ionization states of simulated oxygen, we find good agreeme…
Cosmic evolution and metal aversion in superluminous supernova host galaxies
Bauer, F. E.; Kim, S.; Buchner, J. +21 more
The SUperluminous Supernova Host galaxIES survey aims to provide strong new constraints on the progenitors of superluminous supernovae (SLSNe) by understanding the relationship to their host galaxies. We present the photometric properties of 53 H-poor and 16 H-rich SLSN host galaxies out to z ∼ 4. We model their spectral energy distributions to de…
X-rays across the galaxy population - II. The distribution of AGN accretion rates as a function of stellar mass and redshift.
Georgakakis, A.; Aird, J.; Coil, A. L.
We use deep Chandra X-ray imaging to measure the distribution of specific black hole accretion rates ($L_X$ relative to the stellar mass of the galaxy) and thus trace AGN activity within star-forming and quiescent galaxies, as a function of stellar mass (from $10^{8.5}-10^{11.5} M_\odot$) and redshift (to $z \sim 4$). We adopt near-infrared select…
Circumbinary, not transitional: on the spiral arms, cavity, shadows, fast radial flows, streamers, and horseshoe in the HD 142527 disc
Pinte, Christophe; Lodato, Giuseppe; Casassus, Simon +13 more
We present 3D hydrodynamical models of the HD 142527 protoplanetary disc, a bright and well-studied disc that shows spirals and shadows in scattered light around a 100 au gas cavity, a large horseshoe dust structure in mm continuum emission, together with mysterious fast radial flows and streamers seen in gas kinematics. By considering several pos…