Search Publications
Imaging the Disk and Jet of the Classical T Tauri Star AA Tau
Russell, Ray W.; Sitko, Michael L.; Grady, Carol A. +4 more
Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope…
Gas and dust cooling along the major axis of M 33 (HerM33es). ISO/LWS [C ii] observations
Boquien, M.; Braine, J.; van der Werf, P. +12 more
Aims: We aim to better understand the heating of gas by observing the prominent gas cooling line [C ii] at 158 µm in the low-metallicity environment of the Local Group spiral galaxy M 33 on scales of 280 pc. In particular, we describe the variation of the photoelectric heating efficiency with the galactic environment.
Methods: In t…
The HARPS search for southern extra-solar planets . XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone
Bouchy, F.; Moutou, C.; Queloz, D. +10 more
The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey o…
Dense gas in M 33 (HerM33es)
Boquien, M.; Braine, J.; van der Werf, P. +13 more
Aims: We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these tracers.
Methods: Using the IRAM 30 m telescope, we detected HCN, HCO+, 12CO,…
On the application of ensemble modeling techniques to improve ambient solar wind models
Riley, Pete; Linker, Jon A.; Mikić, Zoran
Ensemble modeling is a method of prediction based on the use of a representative sample of possible future states. Global models of the solar corona and inner heliosphere are now maturing to the point of becoming predictive tools; thus, it is both meaningful and necessary to quantitatively assess their uncertainty and limitations. In this study, w…
Sloshing Cold Fronts in Galaxy Groups and their Perturbing Disk Galaxies: An X-Ray, Optical, and Radio Case Study
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +10 more
We present a combined X-ray, optical, and radio analysis of the galaxy group IC 1860 using the currently available Chandra and XMM data, multi-object spectroscopy data from the literature, and Giant Metrewave Radio Telescope (GMRT) data. The Chandra and XMM imaging and spectroscopy reveal two surface brightness discontinuities at 45 and 76 kpc sho…
Comparison of geoeffectiveness of coronal mass ejections and corotating interaction regions
Vršnak, B.; Verbanac, G.; Bandić, M. +2 more
Context. A detailed comparison of the geomagnetic responses to interplanetary coronal mass ejection (ICMEs) and corotating interaction regions (CIRs) during solar cycle 23 was performed using geomagnetic indices Dst, Ap, and AE.
Aims: We aim to find out if there are relative differences in the response of various magnetospheric current system…
Observations of Ejecta Clouds Produced by Impacts onto Saturn’s Rings
Porco, Carolyn C.; Hedman, Matthew M.; Burns, Joseph A. +8 more
We report observations of dusty clouds in Saturn’s rings, which we interpret as resulting from impacts onto the rings that occurred between 1 and 50 hours before the clouds were observed. The largest of these clouds was observed twice; its brightness and cant angle evolved in a manner consistent with this hypothesis. Several arguments suggest that…
The NGC 5253 star cluster system - I. Standard modelling and infrared-excess sources
Östlin, Göran; de Grijs, Richard; Zackrisson, Erik +1 more
Using high-resolution Hubble Space Telescope data, we re-examine the fundamental properties (ages, masses and extinction values) of the rich star cluster population in the dwarf starburst galaxy NGC 5253. The gain in resolution compared to previous studies is of order a factor of 2 in both spatial dimensions, while our accessible wavelength range …
The Global Implications of the Hard X-Ray Excess in Type 1 Active Galactic Nuclei
Turner, T. J.; Reeves, J. N.; Tatum, M. M. +1 more
Recent evidence for a strong "hard excess" of flux at energies >~ 20 keV in some Suzaku observations of type 1 active galactic nuclei (AGNs) has motivated an exploratory study of the phenomenon in the local type 1 AGN population. We have selected all type 1 AGNs in the Swift Burst Alert Telescope 58 month catalog and cross-correlated them with …