Search Publications
SOFIA Far-infrared Imaging Polarimetry of M82 and NGC 253: Exploring the Supergalactic Wind
Morris, Mark R.; Staguhn, Johannes; Dowell, C. Darren +23 more
We present far-infrared polarimetry observations of M82 at 53 and 154 µm and NGC 253 at 89 µm, which were taken with High-resolution Airborne Wideband Camera-plus (HAWC+) in polarimetry mode on the Stratospheric Observatory for Infrared Astronomy. The polarization of M82 at 53 µm clearly shows a magnetic field geometry perpendicu…
Current Sheets, Magnetic Islands, and Associated Particle Acceleration in the Solar Wind as Observed by Ulysses near the Ecliptic Plane
Zank, Gary P.; Bruno, Roberto; Li, Gang +16 more
Recent studies of particle acceleration in the heliosphere have revealed a new mechanism that can locally energize particles up to several MeV nucleon-1. Stream-stream interactions, as well as the heliospheric current sheet (CS)—stream interactions, lead to formation of large magnetic cavities, bordered by strong CSs, which in turn prod…
Hot Subdwarf Stars Observed in Gaia DR2 and LAMOST DR5
Han, Zhanwen; Deng, Licai; Luo, Yangping +1 more
Combing Gaia DR2 with LAMOST DR5, we spectroscopically identified 924 hot subdwarf stars, among which 32 stars exhibit strong double-lined composite spectra. We measured the effective temperature T eff, surface gravity {log} g, helium abundance y = nHe/nH, and radial velocities (RVs) of 892 non-composite spectra hot subdwarf stars by fi…
Observations of SN 2017ein Reveal Shock Breakout Emission and a Massive Progenitor Star for a Type Ic Supernova
Bi, Shaolan; Rest, A.; Baron, E. +23 more
We present optical and ultraviolet observations of nearby Type Ic supernova (SN Ic) SN 2017ein, as well as a detailed analysis of its progenitor properties from both the early-time observations and the prediscovery Hubble Space Telescope (HST) images. The optical light curves started from within 1 day to ∼275 days after explosion, and optical spec…
Using APOGEE Wide Binaries to Test Chemical Tagging with Dwarf Stars
Majewski, Steven R.; Hayes, Christian R.; Anguiano, Borja +4 more
Stars of a common origin are thought to have similar, if not nearly identical, chemistry. Chemical tagging seeks to exploit this fact to identify Milky Way subpopulations through their unique chemical fingerprints. In this work, we compare the chemical abundances of dwarf stars in wide binaries to test the abundance consistency of stars of a commo…
Stars that Move Together Were Born Together
Conroy, Charlie; Ting, Yuan-Sen; Brown, Anthony G. A. +3 more
It is challenging to reliably identify stars that were born together outside of actively star-forming regions and bound stellar systems. However, conatal stars should be present throughout the Galaxy, and their demographics can shed light on the clustered nature of star formation and the dynamical state of the disk. In previous work we presented a…
A Triple AGN in a Mid-infrared Selected Late-stage Galaxy Merger
Ellison, Sara L.; Ricci, Claudio; Blecha, Laura +11 more
The coevolution of galaxies and the supermassive black holes (SMBHs) at their centers via hierarchical galaxy mergers is a key prediction of ΛCDM cosmology. As gas and dust are funneled to the SMBHs during the merger, the SMBHs light up as active galactic nuclei (AGNs). In some cases, a merger of two galaxies can encounter a third galaxy, leading …
The Red Dead Redemption Survey of Circumgalactic Gas about Massive Galaxies. I. Mass and Metallicity of the Cool Phase
Bowen, David V.; Tejos, Nicolas; Lehner, Nicolas +6 more
We present a search for H I in the circumgalactic medium (CGM) of 21 massive (< {log}{M}\star > ∼ 11.4), luminous red galaxies (LRGs) at z ∼ 0.5. Using UV spectroscopy of QSO sightlines projected within 500 kpc (∼{R}vir}) of these galaxies, we detect H I absorption in 11/21 sightlines, including two partial Lyman limit …
Empirical Modeling of CME Evolution Constrained to ACE/SWICS Charge State Distributions
Landi, Enrico; Rivera, Yeimy J.; Lepri, Susan T. +1 more
It is generally accepted that coronal mass ejections (CMEs) undergo rapid heating as they are released from the Sun. However, to date, the heating mechanism remains an open question. To gain insight into the plasma heating, we derive the density, temperature, and velocity evolution of the 2005 January 9 interplanetary CME event from launch to ion …
The Interface between the Outer Heliosphere and the Inner Local ISM: Morphology of the Local Interstellar Cloud, Its Hydrogen Hole, Strömgren Shells, and 60Fe Accretion
Redfield, Seth; Linsky, Jeffrey L.; Tilipman, Dennis
We describe the interface between the outer heliosphere and the local interstellar medium (LISM) surrounding the Sun. The components of the inner LISM are the four partially ionized clouds (the Local Interstellar Cloud (LIC), G cloud, Blue cloud, and Aql cloud) that are in contact with the outer heliosphere, and ionized gas produced by EUV radiati…