Search Publications
Zooming into the Cosmic Horseshoe: new insights on the lens profile and the source shape
Metcalf, R. Benton; Tessore, Nicolas; Bellagamba, Fabio
The gravitational lens SDSS J1148+1930, also known as the Cosmic Horseshoe, is one of the biggest and most detailed Einstein rings ever observed. We use the forward reconstruction method implemented in the lens-fitting code LENSED to investigate in great detail the properties of the lens and background source. We model the lens with different mass…
Two-dimensional ice mapping of molecular cores
Pontoppidan, K. M.; Noble, J. A.; Fraser, H. J. +1 more
We present maps of the column densities of H2O, CO2 and CO ices towards the molecular cores B 35A, DC 274.2-00.4, BHR 59 and DC 300.7-01.0. These ice maps, probing spatial distances in molecular cores as low as 2200 au, challenge the traditional hypothesis that the denser the region observed, the more ice is present, providin…
Plasma waves confined to the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko
Gunell, H.; Nilsson, H.; Hamrin, M. +11 more
Ion acoustic waves were observed in the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft on 2015 August 3, when the comet was 1.25 au from the Sun. Wave spectra recorded by the Langmuir probe (RPC-LAP), peak near 200 Hz, decrease for higher frequencies and reach the noise floor at approximately 1.5 kHz. These waves w…
Oxygen budget in low-mass protostars: the NGC 1333-IRAS4A R1 shock observed in [O I] at 63 µm with SOFIA-GREAT
Güsten, R.; Simon, R.; Karska, A. +5 more
In molecular outflows from forming low-mass protostars, most oxygen is expected to be locked up in water. However, Herschel observations have shown that typically an order of magnitude or more of the oxygen is still unaccounted for. To test if the oxygen is instead in atomic form, SOFIA-GREAT observed the R1 position of the bright molecular outflo…
Constraining the Enceladus plume using numerical simulation and Cassini data
Trafton, Laurence M.; Levin, Deborah A.; Goldstein, David B. +3 more
Since its discovery, the Enceladus plume has been subjected to intense study due to the major effects that it has on the Saturnian system and the window that it provides into the interior of Enceladus. However, several questions remain and we attempt to answer some of them in this work. In particular, we aim to constrain the H2O product…
Clues to the Formation of Spiral Structure in M51 from the Ages and Locations of Star Clusters
Calzetti, Daniela; Schinnerer, Eva; Whitmore, Bradley C. +8 more
We determine the spatial distributions of star clusters at different ages in the grand-design spiral galaxy M51 using a new catalog based on multi-band images taken with the Hubble Space Telescope (HST). These distributions, when compared with the spiral structure defined by molecular gas, dust, young and old stars, show the following sequence in …
Disentangling the near-infrared continuum spectral components of the inner 500 pc of Mrk 573: two-dimensional maps
Kraemer, S. B.; Crenshaw, D. M.; Storchi-Bergmann, T. +5 more
We present a near-infrared (near-IR) study of the spectral components of the continuum in the inner 500 × 500 pc2 of the nearby Seyfert galaxy Mrk 573 using adaptive optics near-IR integral field spectroscopy with the instrument near-infrared integral field spectrograph of the Gemini North Telescope at a spatial resolution of ∼50 pc. We…
Dynamics of Large-scale Coronal Structures as Imaged during the 2012 and 2013 Total Solar Eclipses
Morgan, Huw; Habbal, Shadia R.; Druckmüller, Miloslav +2 more
White light images acquired at the peak of solar activity cycle 24, during the total solar eclipses of 2012 November 13 and 2013 November 3, serendipitously captured erupting prominences accompanied by CMEs. Application of state-of-the-art image processing techniques revealed the intricate details of two “atypical” large-scale structures, with str…
Hiding in plain sight - recovering clusters of galaxies with the strongest AGN in their cores
Magnier, E. A.; Waters, C.; Edge, A. C. +8 more
A key challenge in understanding the feedback mechanism of active galactic nucleus (AGN) in Brightest Cluster Galaxies (BCGs) is the inherent rarity of catching an AGN during its strong outburst phase. This is exacerbated by the ambiguity of differentiating between AGN and clusters in X-ray observations. If there is evidence for an AGN then the X-…
Post-perihelion photometry of dust grains in the coma of 67P Churyumov-Gerasimenko
Jorda, L.; Lara, L. M.; Bertaux, J. -L. +51 more
We present a photometric analysis of individual dust grains in the coma of comet 67P/Churyumov-Gerasimenko using OSIRIS images taken from 2015 July to 2016 January. We analysed a sample of 555 taken during 18 d at heliocentric distances ranging between 1.25 and 2.04 au and at nucleocentric distances between 80 and 437 km. An automated method to de…