Search Publications
Climbing and falling dunes in Valles Marineris, Mars
Chojnacki, Matthew; Moersch, Jeffrey E.; Burr, Devon M.
Multiple occurrences of “wall dunes” are found several kilometers above the Valles Marineris canyon floor. Dune slip face orientation and bed form morphologies indicate transport direction and whether the wall dunes are climbing dunes or falling dunes. On Earth, these types of dunes form in a unidirectional wind regime and are strongly controlled …
The distributions of the OH Meinel and O(a1Δ-X3Σ) nightglow emissions in the Venus mesosphere based on VIRTIS observations
Drossart, P.; Piccioni, G.; Gérard, J. -C. +2 more
O(aΔ) and recently discovered OH Meinel nightglow emissions have been observed at the limb with the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS-M) instrument on board the Venus Express satellite. Hydroxyl bands belonging to Δv=1 sequence between 2.60and3.14µm and to Δv=2 sequence at 1.40-1.46µm have been unambiguously ide…
Using the ROSAT catalogue to find counterparts for unidentified objects in the first Fermi/LAT catalogue
Masetti, N.; Landi, R.; Malizia, A. +4 more
There are a total of 1451 gamma-ray emitting objects in the Fermi Large Area Telescope First Source Catalogue. The point source location accuracy of typically a few arcmin has allowed the counterparts for many of these sources to be found at other wavelengths, but even so there are 630 which are described as having no plausible counterpart at 80 p…
A detailed study of the main sequence of the globular cluster NGC 6397: can we derive constraints on the existence of multiple populations?
D'Antona, F.; Ventura, P.; di Criscienzo, M.
Context. Globular clusters can no longer be regarded as examples of “simple stellar populations” as all those so far examined contain an important fraction of “second generation” stars, in which the light elements are processed through the hot CNO cycle, and helium variations may be present. Clusters apparently “simple” contain a majority of secon…
Herschel-ATLAS: Blazars in the science demonstration phase field
Andreani, P.; Rodighiero, G.; Valtchanov, I. +54 more
To investigate the poorly constrained sub-mm counts and spectral properties of blazars we searched for these in the Herschel-ATLAS (H-ATLAS) science demonstration phase (SDP) survey catalog. We cross-matched 500 µm sources brighter than 50 mJy with the FIRST radio catalogue. We found two blazars, both previously known. Our study is among the…
The Hα Variations of η Carinae During the 2009.0 Spectroscopic Event
Okazaki, A. T.; Fernández-Lajús, E.; Gies, D. R. +2 more
We report on Hα spectroscopy of the 2009.0 spectroscopic event of η Carinae collected via SMARTS observations using the Cerro Tololo Interamerican Observatory 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a two-month interval around the predicted minimum of η Car. We observed a significant fading of t…
Remarkable Spectral Variability of PDS 456
Kaspi, Shai; Turner, T. J.; O'Brien, Paul T. +3 more
We report on the highest to date signal-to-noise ratio X-ray spectrum of the luminous quasar PDS 456, as obtained during two XMM-Newton orbits in 2007 September. The present spectrum is considerably different from several previous X-ray spectra recorded for PDS 456 since 1998. The ultra-high-velocity outflow seen as recently as 2007 February is no…
NICMOS Observations of the Transiting Hot Jupiter XO-1b
Valenti, Jeff A.; Nelan, Edmund P.; Johns-Krull, Christopher M. +6 more
We refine the physical parameters of the transiting hot Jupiter planet XO-1b and its stellar host XO-1 using Hubble Space Telescope (HST) NICMOS observations. XO-1b has a radius Rp = 1.21 ± 0.03 RJ , and XO-1 has a radius R sstarf = 0.94 ± 0.02 R sun, where the uncertainty in the mass of XO-1 dominates t…
The 3-D extent of the Io UV footprint on Jupiter
Bonfond, B.
The Io footprint (IFP) is the auroral signature of the electromagnetic interaction between Io and Jupiter's magnetosphere. It consists of several spots followed by an extended tail, which are located close to the feet of the magnetic field lines connecting Io to Jupiter. The size of the main spot is a controversial issue, and previously published …
Quiescent and flaring X-ray emission from the nearby M/T dwarf binary SCR 1845-6357
Schmitt, J. H. M. M.; Robrade, J.; Poppenhaeger, K.
Aims: X-ray emission is an important diagnostics to study magnetic activity in very low mass stars that are presumably fully convective and have an effectively neutral photosphere.
Methods: We investigate an XMM-Newton observation of SCR 1845-6357, a nearby, ultracool M 8.5 / T 5.5 dwarf binary. The binary is unresolved in the XMM detect…