Search Publications
High-fidelity view of the structure and fragmentation of the high-mass, filamentary IRDC G11.11-0.12
Henning, T.; Kainulainen, J.; Stutz, A. +1 more
Star formation in molecular clouds is intimately linked to their internal mass distribution. We present an unprecedentedly detailed analysis of the column density structure of a high-mass, filamentary molecular cloud, namely IRDC G11.11-0.12 (G11). We use two novel column density mapping techniques: high-resolution (FWHM = 2″, or ~0.035 pc) dust e…
The horizontal branch in the UV colour-magnitude diagrams - II. The case of M3, M13 and M79
Dalessandro, E.; Salaris, M.; Mucciarelli, A. +2 more
We present a detailed comparison between far-ultraviolet (UV)/optical colour-magnitude diagrams obtained with high-resolution Hubble Space Telescope data and suitable theoretical models for three Galactic globular clusters: M3, M13 and M79.
These systems represents a `classical' example of clusters in the intermediate-metallicity regime that,…Two Beyond-primitive Extrasolar Planetesimals
Koester, D.; Zuckerman, B.; Xu, S. +2 more
Using the Cosmic Origins Spectrograph on board the Hubble Space Telescope, we have obtained high-resolution ultraviolet observations of GD 362 and PG 1225-079, two helium-dominated, externally polluted white dwarfs. We determined or placed useful upper limits on the abundances of two key volatile elements, carbon and sulfur, in both stars; we also…
Connecting stellar mass and star-formation rate to dark matter halo mass out to z ∼ 2
Ivison, R. J.; Ilbert, O.; Béthermin, M. +17 more
We have constructed an extended halo model (EHM) which relates the total stellar mass and star-formation rate (SFR) to halo mass (Mh). An empirical relation between the distribution functions of total stellar mass of galaxies and host halo mass, tuned to match the spatial density of galaxies over 0 < z < 2 and the clustering prope…
Breaking the Obscuring Screen: A Resolved Molecular Outflow in a Buried QSO
Veilleux, Sylvain; Rupke, David S. N.
We present Keck laser guide star adaptive optics observations of the nearby buried quasi-stellar object (QSO) F08572+3915:NW. We use near-infrared integral field data taken with the OH-Suppressing Infra-Red Imaging Spectrograph to reveal a compact disk and molecular outflow using Paα and H2 rotational-vibrational transitions at a spatia…
Solar magnetic fields as revealed by Stokes polarimetry
Stenflo, J. O.
Observational astrophysics started when spectroscopy could be applied to astronomy. Similarly, observational work on stellar magnetic fields became possible with the application of spectro-polarimetry. In recent decades there have been dramatic advances in the observational tools for spectro-polarimetry. The four Stokes parameters that provide a c…
Shock Heating of the Merging Galaxy Cluster A521
Brunetti, G.; Giacintucci, S.; Bourdin, H. +2 more
A521 is an interacting galaxy cluster located at z = 0.247, hosting a low-frequency radio halo connected to an eastern radio relic. Previous Chandra observations hinted at the presence of an X-ray brightness edge at the position of the relic, which may be a shock front. We analyze a deep observation of A521 recently performed with XMM-Newton in or…
Lyα Escape from z ~ 0.03 Star-forming Galaxies: The Dominant Role of Outflows
Leitherer, Claus; Wofford, Aida; Salzer, John
The usefulness of H I Lyα photons for characterizing star formation in the distant universe is limited by our understanding of the astrophysical processes that regulate their escape from galaxies. These processes can only be observed in detail out to a few × 100 Mpc. Past nearby (z < 0.3) spectroscopic studies are based on small samples and/or …
What the ancient phyllosilicates at Mawrth Vallis can tell us about possible habitability on early Mars
Murchie, Scott L.; Bishop, Janice L.; Parente, Mario +5 more
Phyllosilicate deposits on Mars provide an opportunity to evaluate aqueous activity and the possibility that habitable environments may have existed during the Noachian period there. Analysis of hyperspectral visible/near-infrared (VNIR) Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) images has shown…
The escape of heavy atoms from the ionosphere of HD209458b. II. Interpretation of the observations
Yelle, R. V.; Lavvas, P.; Koskinen, T. T. +1 more
Transits in the H I 1216 Å (Lyman α), O I 1334 Å, C II 1335 Å, and Si III 1206.5 Å lines constrain the properties of the upper atmosphere of HD209458b. In addition to probing the temperature and density profiles in the thermosphere, they have implications for the properties of the lower atmosphere. Fits to the observations with a simple empirical …