Search Publications
Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud - II. Relative ages and distances for six ancient globular clusters
Cohen, Roger E.; Wagner-Kaiser, R.; Sarajedini, Ata +6 more
We analyse Hubble Space Telescope observations of six globular clusters in the Large Magellanic Cloud (LMC) from programme GO-14164 in Cycle 23. These are the deepest available observations of the LMC globular cluster population; their uniformity facilitates a precise comparison with globular clusters in the Milky Way. Measuring the magnitude of t…
A Search for Spectral Hysteresis and Energy-dependent Time Lags from X-Ray and TeV Gamma-Ray Observations of Mrk 421
Maraschi, L.; Covino, S.; Antonelli, L. A. +222 more
Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray bands, where the broadband spectral energy distributions usually peak. In this work, we report on three “targe…
Spectroscopic confirmation of an ultra-faint galaxy at the epoch of reionization
Pentericci, Laura; Schmidt, Kasper B.; Treu, Tommaso +11 more
Within one billion years of the Big Bang, intergalactic hydrogen was ionized by sources emitting ultraviolet and higher energy photons. This was the final phenomenon to globally affect all the baryons (visible matter) in the Universe. It is referred to as cosmic reionization and is an integral component of cosmology. It is broadly expected that in…
Strength of the Solar Coronal Magnetic Field - A Comparison of Independent Estimates Using Contemporaneous Radio and White-Light Observations
Kumari, Anshu; Ramesh, R.; Kathiravan, C. +1 more
We estimated the coronal magnetic field strength (B ) during the 23 July 2016 coronal mass ejection (CME) event using i) the flux rope structure of the CME in the white-light coronagraph images and ii) the band-splitting in the associated type II burst. No models were assumed for the coronal electron density (N (r )) we used in the estimation. The…
Chemical tagging of the Ursa Major moving group. A northern selection of FGK stars
Montes, D.; González Hernández, J. I.; Tabernero, H. M. +1 more
Context. Stellar kinematic groups are kinematically coherent groups of stars that might have a common origin. These groups spread through the Galaxy over time owing to tidal effects caused by Galactic rotation and disk heating. However, the chemical information survives these processes.
Aims: The information provided by analysis of chemical e…
Mars sedimentary rock erosion rates constrained using crater counts, with applications to organic-matter preservation and to the global dust cycle
Kite, Edwin S.; Mayer, David P.
Small-crater counts on Mars light-toned sedimentary rock are often inconsistent with any isochron; these data are usually plotted then ignored. We show (using an 18-HiRISE-image, > 104-crater dataset) that these non-isochron crater counts are often well-fit by a model where crater production is balanced by crater obliteration via ste…
The Structure of Chariklo’s Rings from Stellar Occultations
Colas, F.; Bérard, D.; Kervella, P. +79 more
Two narrow and dense rings (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on 2013 June 3. Following this discovery, we planned observations of several occultations by Chariklo’s system in order to better characterize the physical properties of the ring and main body. Here, we u…
A First Comparison of Millimeter Continuum and Mg II Ultraviolet Line Emission from the Solar Chromosphere
De Pontieu, B.; Schmit, D.; Leenaarts, J. +4 more
We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). Both millimeter/submillimeter-λ continuum emission and ultraviolet (UV) line emission originate from the solar chromosphere and both have the potential to serve as powerful and complementary diag…
Modeling dust emission in the Magellanic Clouds with Spitzer and Herschel
Gordon, Karl D.; Bot, Caroline; Chastenet, Jérémy +4 more
Context. Dust modeling is crucial to infer dust properties and budget for galaxy studies. However, there are systematic disparities between dust grain models that result in corresponding systematic differences in the inferred dust properties of galaxies. Quantifying these systematics requires a consistent fitting analysis.
Aims: We compare th…
Cluster and field elliptical galaxies at z 1.3. The marginal role of the environment and the relevance of the galaxy central regions
Marchesini, D.; Gargiulo, A.; Saracco, P. +1 more
Aims: The aim of this work is twofold: first, to assess whether the population of elliptical galaxies in cluster at z 1.3 differs from the population in the field and whether their intrinsic structure depends on the environment where they belong; second, to constrain their properties 9 Gyr back in time through the study of their scaling relat…