Search Publications
Mapping Outflowing Gas in the Fermi Bubbles: A UV Absorption Survey of the Galactic Nuclear Wind
Jenkins, Edward B.; Savage, Blair D.; Lockman, Felix J. +5 more
Using new ultraviolet (UV) spectra of five background quasars from the Cosmic Origins Spectrograph on the Hubble Space Telescope, we analyze the low-latitude ( $| b| =20^\circ \mbox{--}30^\circ $ ) regions of the Fermi Bubbles, the giant gamma-ray-emitting lobes at the Galactic Center. We combine these data with previous UV and atomic hydrogen (H …
CTCV J2056-3014: An X-Ray-faint Intermediate Polar Harboring an Extremely Fast-spinning White Dwarf
Mukai, K.; Oliveira, A. S.; Rodrigues, C. V. +2 more
We report on XMM-Newton X-ray observations that reveal CTCV J2056-3014 to be an unusual accretion-powered, intermediate polar (IP) system. It is a member of the class of X-ray-faint IPs whose space density remains unconstrained but potentially very high, with Lx,0.3-12 keV of 1.8 × 1031 erg s-1. We discovered a coh…
Evidence for a Coronal Shock Wave Origin for Relativistic Protons Producing Solar Gamma-Rays and Observed by Neutron Monitors at Earth
Kouloumvakos, Athanasios; Rouillard, Alexis P.; Papaioannou, Athanasios +4 more
We study the solar eruptive event on 2017 September 10 that produced long-lasting >100 MeV γ-ray emission and a ground level enhancement (GLE72). The origin of the high-energy ions producing late-phase gamma-ray emission (LPGRE) is still an open question, but a possible explanation is proton acceleration at coronal shocks produced by coronal ma…
The Magnetic Field of the Active Planet-hosting M Dwarf AU Mic
Kochukhov, Oleg; Reiners, Ansgar
AU Mic is a young, very active M dwarf star with a debris disk and at least one transiting Neptune-size planet. Here we present a detailed analysis of the magnetic field of AU Mic based on previously unpublished high-resolution optical and near-infrared spectropolarimetric observations. We report a systematic detection of circular and linear polar…
A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536
Millon, Martin; Bonvin, Vivien; Bentz, Misty C. +4 more
We use 13 seasons of R-band photometry from the 1.2 m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply imaged lensed quasar WFI 2026-4536. The lightcurves exhibit ∼0.2 mag of uncorrelated variability across all epochs and a prominent single feature of ∼0.1 mag within a single season. We analyze this va…
Amplification of Brightness Variability by Active-region Nesting in Solar-like Stars
Solanki, Sami K.; Shapiro, Alexander I.; Krivova, Natalie A. +1 more
Kepler observations revealed that hundreds of stars with near-solar fundamental parameters and rotation periods have much stronger and more regular brightness variations than the Sun. Here we identify one possible reason for the peculiar behavior of these stars. Inspired by solar nests of activity, we assume that the degree of inhomogeneity of act…
A Supernova Candidate at z = 0.092 in XMM-Newton Archival Data
Mereghetti, Sandro; Esposito, Paolo; Tiengo, Andrea +14 more
During a search for X-ray transients in the XMM-Newton archive within the EXTraS project, we discovered a new X-ray source that is detected only during an ∼5 min interval of an ∼21 hr-long observation performed on 2011 June 21 (EXMM 023135.0-603743, probability of a random Poissonian fluctuation: ∼1.4 × 10-27). With dedicated follow-up …
The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS
Chaplin, William J.; Stassun, Keivan G.; Metcalfe, Travis S. +29 more
Most previous efforts to calibrate how rotation and magnetic activity depend on stellar age and mass have relied on observations of clusters, where isochrones from stellar evolution models are used to determine the properties of the ensemble. Asteroseismology employs similar models to measure the properties of an individual star by matching its no…
Discovery of a Giant Radio Fossil in the Ophiuchus Galaxy Cluster
Wik, D. R.; Giacintucci, S.; Markevitch, M. +3 more
The Ophiuchus galaxy cluster exhibits a curious concave gas density discontinuity at the edge of its cool core. It was discovered in the Chandra X-ray image by Werner and collaborators, who considered the possibility of it being a boundary of an active galactic nucleus (AGN)-inflated bubble located outside the core, but discounted this possibility…
Three-dimensional Kinematic Reconstruction of the Optically Emitting, High-velocity, Oxygen-rich Ejecta of Supernova Remnant N132D
Law, Charles J.; Orlando, Salvatore; Gladders, Michael D. +9 more
We present a three-dimensional kinematic reconstruction of the optically emitting, oxygen-rich ejecta of supernova remnant N132D in the Large Magellanic Cloud (LMC). Data were obtained with the 6.5 m Magellan telescope in combination with the IMACS+GISMO instrument and survey [O III] λλ4959, 5007 line emission in a ∼3' × 3' region centered on N132…