Search Publications
Study of the X-ray activity of Sagittarius A* during the 2011 XMM-Newton campaign
Grosso, Nicolas; Mossoux, Enmanuelle; Porquet, Delphine +1 more
Context. At the dynamical center of the Milky Way, there is the closest supermassive black hole: Sgr A*. Its non-flaring luminosity is several orders of magnitude lower than the Eddington luminosity, but flares can be observed in the infrared and X-rays. This flaring activity can help us to understand radiation mechanisms from Sgr A*.
Aims: O…
A progressive black top hat transformation algorithm for estimating valley volumes on Mars
Luo, Wei; Jung, Jaehoon; Pingel, Thomas +2 more
The depth of valley incision and valley volume are important parameters in understanding the geologic history of early Mars, because they are related to the amount sediments eroded and the quantity of water needed to create the valley networks (VNs). With readily available digital elevation model (DEM) data, the Black Top Hat (BTH) transformation,…
Down-tail mass loss by plasmoids in Jupiter's and Saturn's magnetospheres
Jackman, C. M.; Nichols, J. D.; Cowley, S. W. H.
Recent estimates of the plasma mass-loss rates by the formation and down-tail propagation of plasmoids observed in the plasma sheet in Jupiter's and Saturn's magnetosphere fall short of inner moon source rates by at least an order of magnitude. Here we argue that on the time scale between large-scale disconnection events, ~15 h at Jupiter and ~45 …
Low-Frequency Type-II Radio Detections and Coronagraph Data Employed to Describe and Forecast the Propagation of 71 CMEs/Shocks
St. Cyr, O. C.; Kaiser, M. L.; Gopalswamy, N. +3 more
Motivated by improving predictions of arrival times at Earth of shocks driven by coronal mass ejections (CMEs), we have analyzed 71 Earth-directed events in different stages of their propagation. The study is primarily based on approximated locations of interplanetary (IP) shocks derived from Type-II radio emissions detected by the Wind/WAVES expe…
Variations in peak electron densities in the ionosphere of Mars over a full solar cycle
Gurnett, D. A.; Morgan, D. D.; Withers, Paul
Peak electron densities in the ionosphere of Mars are strongly influenced by the intensity of ionizing solar flux and hence by the solar cycle. Datasets used in previous studies of this relationship have incompletely sampled the range of solar irradiances encountered over a full solar cycle. Here, thousands of Mars Global Surveyor radio occultatio…
A multiwavelength exploration of the [C II]/IR ratio in H-ATLAS/GAMA galaxies out to z = 0.2
Valtchanov, I.; Ivison, R. J.; Smith, M. +23 more
We explore the behaviour of [C II] λ157.74 µm forbidden fine-structure line observed in a sample of 28 galaxies selected from ∼ 50 deg2 of the Herschel-Astrophysical Terahertz Large Area Survey survey. The sample is restricted to galaxies with flux densities higher than S160 µm > 150 mJy and optical spectra fro…
Nearby Clumpy, Gas Rich, Star-forming Galaxies: Local Analogs of High-redshift Clumpy Galaxies
Guzmán, R.; Garland, C. A.; Pisano, D. J. +3 more
Luminous compact blue galaxies (LCBGs) have enhanced star formation rates (SFRs) and compact morphologies. We combine Sloan Digital Sky Survey data with H i data of 29 LCBGs at redshift z ∼ 0 to understand their nature. We find that local LCBGs have high atomic gas fractions (∼50%) and SFRs per stellar mass consistent with some high-redshift star-…
On the Origin of the 11.3 Micron Unidentified Infrared Emission Feature
Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza
The 11.3 µm emission feature is a prominent member of the family of unidentified infrared emission (UIE) bands and is frequently attributed to out-of-plane bending modes of polycyclic aromatic hydrocarbon (PAH) molecules. We have performed quantum mechanical calculations of 60 neutral PAH molecules and found that it is difficult to reconcile…
New constraints on the CH4 vertical profile in Uranus and Neptune from Herschel observations
Hartogh, P.; Lellouch, E.; Feuchtgruber, H. +6 more
Dedicated line observations of CH4 rotational lines performed with Herschel/PACS and HIFI in 2009-2011 provide new inferences of the mean methane profile in the upper tropospheres and stratospheres of Uranus and Neptune. At Uranus, CH4 is found to be near saturation, with a ~9 × 10-4 tropopause/lower stratosphere m…
Pan-STARRS1 variability of XMM-COSMOS AGN. I. Impact on photometric redshifts
Salvato, M.; Chambers, K. C.; Flewelling, H. +12 more
Aims: Upcoming large area sky surveys like Euclid and eROSITA, which are dedicated to studying the role of dark energy in the expansion history of the Universe and the three-dimensional mass distribution of matter, crucially depend on accurate photometric redshifts. The identification of variable sources, such as active galactic nuclei (AGNs)…