Search Publications
The New Magnetar SGR J1830-0645 in Outburst
Tiengo, A.; Rea, N.; Esposito, P. +13 more
The detection of a short hard X-ray burst and an associated bright soft X-ray source by the Swift satellite in 2020 October heralded a new magnetar in outburst, SGR J1830-0645. Pulsations at a period of ∼10.4 s were detected in prompt follow-up X-ray observations. We present here the analysis of the Swift/Burst Alert Telescope burst, of XMM-Newton…
Coronal Heating and Solar Wind Formation in Quiet Sun and Coronal Holes: A Unified Scenario
Solanki, Sami K.; Tripathi, Durgesh; Nived, V. N.
Coronal holes (CHs) are darker than the quiet Sun (QS) when observed in coronal channels. This study aims to understand the similarities and differences between CHs and QS in the transition region using the Si IV 1394 Å line, recorded by the Interface Region Imaging Spectrograph, by considering the distribution of magnetic field measured by the He…
A Blueprint for the Milky Way's Stellar Populations. II. Improved Isochrone Calibration in the SDSS and Pan-STARRS Photometric Systems
Beers, Timothy C.; An, Deokkeun
We improve the identification and isolation of individual stellar populations in the Galactic halo based on an updated set of empirically calibrated stellar isochrones in the Sloan Digital Sky Survey and Pan-STARRS 1 photometric systems. Along the Galactic prime meridian (l = 0° and 180°), where proper motions and parallaxes from Gaia DR2 can be u…
The Cosmic Ultraviolet Baryon Survey (CUBS). II. Discovery of an H2-bearing DLA in the Vicinity of an Early-type Galaxy at z = 0.576
Faucher-Giguère, Claude-André; Johnson, Sean D.; Petitjean, Patrick +18 more
We report the serendipitous detection of an H2-bearing damped Lyα absorber at z = 0.576 in the spectrum of the QSO J0111-0316 in the Cosmic Ultraviolet Baryon Survey. Spectroscopic observations from Hubble Space Telescope-COS in the far-ultraviolet reveal a damped absorber with log[N(H I)/cm-2] = 20.1 ± 0.2 and log[N(H2<…
The Far-away Blues: Exploring the Furthest Extents of the Boötes I Ultra-faint Dwarf Galaxy
Wyse, Rosemary F. G.; Filion, Carrie
Establishing the spatial extents and the nature of the outer stellar populations of dwarf galaxies is necessary for the determination of their total masses, current dynamical states, and past evolution. We here describe our investigation of the outer stellar content of the Boötes I ultra-faint dwarf galaxy, a satellite of the the Milky Way. We ide…
The Spatial and Temporal Variations of Turbulence in a Solar Flare
Kontar, Eduard P.; Jeffrey, Natasha L. S.; Stores, Morgan
Magnetohydrodynamic plasma turbulence is believed to play a vital role in the production of energetic electrons during solar flares, and the nonthermal broadening of spectral lines is a key sign of this turbulence. Here, we determine how flare turbulence evolves in time and space using spectral profiles of Fe XXIV, Fe XXIII, and Fe XVI, observed b…
ν Gem: A Hierarchical Triple System with an Outer Be Star
Gies, Douglas R.; Klement, Robert; Rivinius, Thomas +17 more
Time series of spectroscopic, speckle-interferometric, and optical long-baseline-interferometric observations confirm that ν Gem is a hierarchical triple system. It consists of an inner binary composed of two B-type stars and an outer classical Be star. Several photospheric spectral lines of the inner components were disentangled, revealing two st…
First Cospatial Comparison of Stellar, Neutral-gas, and Ionized-gas Metallicities in a Metal-rich Galaxy: M83
Faucher-Giguère, Claude-André; Hafen, Zachary; Kumari, Nimisha +14 more
We carry out a comparative analysis of the metallicities from the stellar, neutral-gas, and ionized-gas components in the metal-rich spiral galaxy M83. We analyze spectroscopic observations taken with the Hubble Space Telescope, the Large Binocular Telescope, and the Very Large Telescope. We detect a clear depletion of the H I gas, as observed fro…
High-resolution Extinction Map in the Direction of the Strongly Obscured Bulge Fossil Fragment Liller 1
Pallanca, Cristina; Dalessandro, Emanuele; Ferraro, Francesco R. +11 more
We used optical images acquired with the Wide Field Camera of the Advanced Camera for Surveys on board the Hubble Space Telescope and near-infrared data from Gemini Multi-conjugate Adaptive Optics System (GeMS)/Gemini South Adaptive Optics Imager (GSAOI) to construct a high-resolution extinction map in the direction of the bulge stellar system Lil…
Solar Energetic Electron Events Associated with Hard X-Ray Flares
Krucker, Säm; Su, Yang; Mason, Glenn M. +3 more
We investigate 16 solar energetic electron (SEE) events measured by WIND/3DP with a double-power-law spectrum and the associated western hard X-ray (HXR) flares measured by RHESSI with good count statistics, from 2002 February to 2016 December. In all the 16 cases, the presence of an SEE power-law spectrum extending down to ≤5 keV at 1 au implies …