Search Publications
NICER X-Ray Observations of Seven Nearby Rotation-powered Millisecond Pulsars
Chakrabarty, Deepto; Bogdanov, Slavko; Deneva, Julia S. +18 more
The Neutron star Interior Composition Explorer observed several rotation-powered millisecond pulsars (MSPs) to search for or confirm the presence of X-ray pulsations. When broad and sine-like, these pulsations may indicate thermal emission from hot polar caps at the magnetic poles on the neutron star surface. We report confident detections (≥4.7σ …
Multi-wavelength Properties of Type 1 and Type 2 AGN Host Galaxies in the Chandra-COSMOS Legacy Survey
Lusso, Elisabeta; Marchesi, Stefano; Onodera, Masato +6 more
We investigate the multi-wavelength properties of host galaxies of 3701 X-ray-selected active galactic nuclei (AGNs) out to z ∼ 5 in the Chandra-COSMOS Legacy Survey. Thanks to the extensive multi-wavelength photometry available in the COSMOS field, we derive AGN luminosities, host stellar masses, and star formation rates (SFRs) via a multi-compon…
Dissecting the AGN Disk-Jet System with Joint VLBI-Gaia Analysis
Kovalev, Y. Y.; Plavin, A. V.; Petrov, L. Y.
We analyze differences in positions of active galactic nuclei (AGNs) between Gaia data release 2 and very long baseline interferometry (VLBI) and compare the significant VLBI-to-Gaia offsets in more than 1000 objects with their jet directions. Remarkably at least three-fourths of the significant offsets are confirmed to occur downstream or upstrea…
Ambient Column Densities of Highly Ionized Oxygen in Precipitation-limited Circumgalactic Media
Voit, G. Mark
Many of the baryons associated with a galaxy reside in its circumgalactic medium (CGM), in a diffuse volume-filling phase at roughly the virial temperature. Much of the oxygen produced over cosmic time by the galaxy’s stars also ends up there. The resulting absorption lines in the spectra of UV and X-ray background sources are powerful diagnostics…
Evidence for an Aspherical Population III Supernova Explosion Inferred from the Hyper-metal-poor Star HE 1327-2326
Placco, Vinicius M.; Tominaga, Nozomu; Nomoto, Ken'ichi +6 more
We present observational evidence that an aspherical supernova explosion could have occurred in the first stars in the early universe. Our results are based on the first determination of a Zn abundance in a Hubble Space Telescope/Cosmic Origins Spectrograph high-resolution UV spectrum of a hyper-metal-poor (HMP) star, HE 1327-2326, with {{[Fe/H]}}…
SI IV Resonance Line Emission during Solar Flares: Non-LTE, Nonequilibrium, Radiation Transfer Simulations
Kerr, Graham S.; Carlsson, Mats; Young, Peter R. +2 more
The Interface Region Imaging Spectrograph routinely observes the Si IV resonance lines. When analyzing quiescent observations of these lines, it has typically been assumed that they form under optically thin conditions. This is likely valid for the quiescent Sun, but this assumption has also been applied to the more extreme flaring scenario. We us…
The ALMA Spectroscopic Survey in the HUDF: Nature and Physical Properties of Gas-mass Selected Galaxies Using MUSE Spectroscopy
Carilli, Chris; Somerville, Rachel S.; Bacon, Roland +31 more
We discuss the nature and physical properties of gas-mass selected galaxies in the ALMA spectroscopic survey (ASPECS) of the Hubble Ultra Deep Field (HUDF). We capitalize on the deep optical integral-field spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE) HUDF Survey and multiwavelength data to uniquely associate all 16 line emitters,…
Validation of the Alfvén Wave Solar Atmosphere Model (AWSoM) with Observations from the Low Corona to 1 au
van der Holst, Bart; Lamy, Philippe; Vásquez, Alberto M. +9 more
We perform a validation study of the latest version of the Alfvén Wave Solar atmosphere Model (AWSoM) within the Space Weather Modeling Framework. To do so, we compare the simulation results of the model with a comprehensive suite of observations for Carrington rotations representative of the solar minimum conditions extending from the solar coron…
Global 3D Hydrodynamic Modeling of In-transit Lyα Absorption of GJ 436b
Lammer, H.; Khodachenko, M. L.; Shaikhislamov, I. F. +5 more
Using a global 3D, fully self-consistent, multifluid hydrodynamic model, we simulate the escaping upper atmosphere of the warm Neptune GJ 436b, driven by the stellar X-ray and ultraviolet (XUV) radiation impact and gravitational forces and interacting with the stellar wind. Under the typical parameters of XUV flux and stellar wind plasma expected …
Morphologies of ∼190,000 Galaxies at z = 0-10 Revealed with HST Legacy Data. III. Continuum Profile and Size Evolution of Lyα Emitters
Ouchi, Masami; Harikane, Yuichi; Shibuya, Takatoshi +1 more
We present the redshift evolution of the radial surface brightness profile of the rest-frame UV and optical stellar continua for 9119 Lyα emitters (LAEs) at z ≃ 0-8 and 0-2, respectively. Using Hubble Space Telescope data and the LAE catalogs taken from the literature, we derive the structural quantities of the 9119 LAEs, and of ≃180,000 of photo-…