Search Publications
Herschel/PACS Spectroscopic Survey of Protostars in Orion: The Origin of Far-infrared CO Emission
Maret, S.; Manoj, P.; Di Francesco, J. +14 more
We present far-infrared (57-196 µm) spectra of 21 protostars in the Orion molecular clouds. These were obtained with the Photodetector Array Camera and Spectrometer (PACS) on board the Herschel Space observatory as part of the Herschel Orion Protostar Survey program. We analyzed the emission lines from rotational transitions of CO, involving…
Rocket dust storms and detached dust layers in the Martian atmosphere
Määttänen, Anni; Forget, François; Spiga, Aymeric +2 more
Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that t…
HD 140283: A Star in the Solar Neighborhood that Formed Shortly after the Big Bang
Schaefer, Gail H.; Nelan, Edmund P.; Bond, Howard E. +2 more
HD 140283 is an extremely metal-deficient and high-velocity subgiant in the solar neighborhood, having a location in the Hertzsprung-Russell diagram where absolute magnitude is most sensitive to stellar age. Because it is bright, nearby, unreddened, and has a well-determined chemical composition, this star avoids most of the issues involved in age…
A black-hole mass measurement from molecular gas kinematics in NGC4526
Sarzi, Marc; Cappellari, Michele; Davis, Timothy A. +2 more
The masses of the supermassive black holes found in galaxy bulges are correlated with a multitude of galaxy properties, leading to suggestions that galaxies and black holes may evolve together. The number of reliably measured black-hole masses is small, and the number of methods for measuring them is limited, holding back attempts to understand th…
Asymmetric Solar Polar Field Reversals
Svalgaard, Leif; Kamide, Yohsuke
The solar polar fields reverse because magnetic flux from decaying sunspots moves toward the poles, with a preponderance of flux from the trailing spots. If there is a strong asymmetry, in the sense that most activity is in the northern hemisphere, then that excess flux will move toward the north pole and reverse that pole first. If there is more …
A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies
Gombosi, T. I.; Landi, E.; Jin, M. +3 more
We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Al…
Testing modified gravity with Planck: The case of coupled dark energy
Pettorino, Valeria
The Planck collaboration has recently published maps of the cosmic microwave background (CMB) radiation, in good agreement with a ΛCDM model, a fit especially valid for multipoles ℓ>40. We explore here the possibility that dark energy is dynamical and gravitational attraction between dark matter particles is effectively different from the stand…
Titan’s surface and atmosphere from Cassini/VIMS data with updated methane opacity
Le Mouélic, S.; Rodriguez, S.; Lellouch, E. +13 more
We present an analysis of Titan data acquired by the Cassini Visual and Infrared Mapping Spectrometer (VIMS), making use of recent improvements in methane spectroscopic parameters in the region 1.3-5.2 µm. We first analyzed VIMS spectra covering a 8 × 10-km2 area near the Huygens landing site in order to constrain the single scatt…
GASPS—A Herschel Survey of Gas and Dust in Protoplanetary Disks: Summary and Initial Statistics
Pinte, C.; Dent, W. R. F.; Woitke, P. +47 more
We describe a large-scale far-infrared line and continuum survey of protoplanetary disk through to young debris disk systems carried out using the ACS instrument on the Herschel Space Observatory. This Open Time Key program, known as GASPS (Gas Survey of Protoplanetary Systems), targeted ~250 young stars in narrow wavelength regions covering the […
The properties of the extended warm ionised gas around low-redshift QSOs and the lack of extended high-velocity outflows
Jahnke, K.; Husemann, B.; Sánchez, S. F. +1 more
We present a detailed analysis of a large sample of 31 low-redshift, mostly radio-quiet type 1 quasi-stellar objects (QSOs) observed with integral field spectroscopy to study their extended emission-line regions (EELRs). We focus on the ionisation state of the gas, size and luminosity of extended narrow line regions (ENLRs), which corresponds to t…