Search Publications
Non-Maxwellian Analysis of the Transition-region Line Profiles Observed by the Interface Region Imaging Spectrograph
Polito, Vanessa; Del Zanna, Giulio; Testa, Paola +2 more
We investigate the nature of the spectral line profiles for transition-region (TR) ions observed with the Interface Region Imaging Spectrograph (IRIS). In this context, we analyzed an active-region observation performed by IRIS in its 1400 Å spectral window. The TR lines are found to exhibit significant wings in their spectral profiles, which can …
Cloud Structure of Three Galactic Infrared Dark Star-forming Regions from Combining Ground- and Space-based Bolometric Observations
Li, Di; Qian, Lei; Ginsburg, Adam +12 more
We have modified the iterative procedure introduced by Lin et al., to systematically combine the submillimeter images taken from ground-based (e.g., CSO, JCMT, APEX) and space (e.g., Herschel, Planck) telescopes. We applied the updated procedure to observations of three well-studied Infrared Dark Clouds (IRDCs): G11.11-0.12, G14.225-0.506, and G28…
Line Ratios for Solar Wind Charge Exchange with Comets
Gu, L.; Kaastra, J.; Shelton, R. L. +4 more
Charge exchange (CX) has emerged in X-ray emission modeling as a significant process that must be considered in many astrophysical environments—particularly comets. Comets host an interaction between solar wind ions and cometary neutrals to promote solar wind charge exchange (SWCX). X-ray observatories provide astronomers and astrophysicists with …
High-resolution Statistics of Solar Wind Turbulence at Kinetic Scales Using the Magnetospheric Multiscale Mission
Russell, C. T.; Fuselier, S. A.; Torbert, R. B. +10 more
Using data from the Magnetospheric Multiscale (MMS) and Cluster missions obtained in the solar wind, we examine second-order and fourth-order structure functions at varying spatial lags normalized to ion inertial scales. The analysis includes direct two-spacecraft results and single-spacecraft results employing the familiar Taylor frozen-in flow a…
ALMA Pinpoints a Strong Overdensity of U/LIRGs in the Massive Cluster XCS J2215 at z = 1.46
Smail, Ian; Hilton, Matt; Swinbank, A. M. +3 more
We surveyed the core regions of the z = 1.46 cluster XCS J2215.9-1738 with the Atacama Large Millimeter Array (ALMA) and the MUSE-GALACSI spectrograph on the Very Large Telescope (VLT). We obtained high spatial resolution observations with ALMA of the 1.2 mm dust continuum and molecular gas emission in the central regions of the cluster. These obs…
Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors
Mori, Hideyuki; Yamaguchi, Hiroya; Badenes, Carles +8 more
The physical process whereby a carbon-oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new…
Gas Sloshing Regulates and Records the Evolution of the Fornax Cluster
Jones, Christine; Nulsen, Paul E. J.; Kraft, Ralph P. +7 more
We present results of a joint Chandra and XMM-Newton analysis of the Fornax Cluster, the nearest galaxy cluster in the southern sky. Signatures of merger-induced gas sloshing can be seen in the X-ray image. We identify four sloshing cold fronts in the intracluster medium, residing at radii of 3 kpc (west), 10 kpc (northeast), 30 kpc (southwest), a…
Dust Abundance Variations in the Magellanic Clouds: Probing the Life-cycle of Metals with All-sky Surveys
Bot, Caroline; Roman-Duval, Julia; Gordon, Karl +1 more
Observations and modeling suggest that dust abundance (gas-to-dust ratio, G/D) depends on (surface) density. Variations of the G/D provide timescale constraints for the different processes involved in the life cycle of metals in galaxies. Recent G/D measurements based on Herschel data suggest a factor of 5-10 decrease in dust abundance between the…
The HDUV Survey: Six Lyman Continuum Emitter Candidates at z ∼ 2 Revealed by HST UV Imaging
Oesch, P. A.; Carollo, C. M.; Nelson, E. J. +14 more
We present six galaxies at z∼ 2 that show evidence of Lyman continuum (LyC) emission based on the newly acquired UV imaging of the Hubble Deep UV legacy survey (HDUV) conducted with the WFC3/UVIS camera on the Hubble Space Telescope (HST). At the redshift of these sources, the HDUV F275W images partially probe the ionizing continuum. By exploiting…
Formation of Methylamine and Ethylamine in Extraterrestrial Ices and Their Role as Fundamental Building Blocks of Proteinogenic α-amino Acids
Kaiser, Ralf I.; Förstel, Marko; Bergantini, Alexandre +2 more
The -CH-NH2 moiety represents the fundamental building block of all proteinogenic amino acids, with the cyclic amino acid proline being a special case (-CH-NH- in proline). Exploiting a chemical retrosynthesis, we reveal that methylamine (CH3NH2) and/or ethylamine (CH3CH2NH2) are es…