Search Publications
Rotating dust particles in the coma of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +43 more
Context. During September and October 2014, the OSIRIS cameras onboard the ESA Rosetta mission detected millions of single particles. Many of these dust particlesappear as long tracks (due to both the dust proper motion and the spacecraft motion during the exposure time) with a clear brightness periodicity.
Aims: We interpret the observed per…
Upstream proton cyclotron waves at Venus near solar maximum
Lundin, R.; Volwerk, M.; Mazelle, C. +3 more
magnetometer data of Venus Express are analyzed for the occurrence of waves at the proton cyclotron frequency in the spacecraft frame in the upstream region of Venus, for conditions of rising solar activity. The data of two Venus years up to the time of highest sunspot number so far (1 Mar 2011 to 31 May 2012) are studied to reveal the properties …
Periodic signals from the Circinus region: two new cataclysmic variables and the ultraluminous X-ray source candidate GC X-1
Sidoli, L.; Esposito, P.; Israel, G. L. +5 more
The examination of two 2010 Chandra ACIS (Advanced CCD Imaging Spectrometer) exposures of the Circinus galaxy resulted in the discovery of two pulsators: CXO J141430.1-651621 and CXOU J141332.9-651756. We also detected 26 ks pulsations in CG X-1, consistently with previous measures. For ∼40 other sources, we obtained limits on periodic modulations…
Estimate of the erosion rate from H2O mass-loss measurements from SWAN/SOHO in previous perihelions of comet 67P/Churyumov-Gerasimenko and connection with observed rotation rate variations
Bertaux, Jean-Loup
Context. The SWAN Lyman α photometer onboard SOHO monitored the hydrogen cloud around comet 67P/Churyumov-Gerasimenko (67P) postperihelion at the three last perihelions in 1996, 2002, and 2009.
Aims: Combining the SWAN results with some new Rosetta data allows estimating the erosion rate of the comet, quantified by the thickness of a layer th…
The mutual orbit, mass, and density of the large transneptunian binary system Varda and Ilmarë
Roe, H. G.; Trujillo, C. A.; Thirouin, A. +7 more
From observations by the Hubble Space Telescope, Keck II Telescope, and Gemini North Telescope, we have determined the mutual orbit of the large transneptunian object (174567) Varda and its satellite Ilmarë. These two objects orbit one another in a highly inclined, circular or near-circular orbit with a period of 5.75 days and a semimajor axis of …
Galaxy sizes as a function of environment at intermediate redshift from the ESO Distant Cluster Survey
Aragón-Salamanca, Alfonso; Vulcani, Benedetta; Zaritsky, Dennis +5 more
In order to assess whether the environment has a significant effect on galaxy sizes, we compare the mass-size relations of cluster and field galaxies in the 0.4 < z < 0.8 redshift range from the ESO Distant Cluster Survey (EDisCS) using Hubble Space Telescope images. We analyse two mass-selected samples, one defined using photometric redshif…
Saturn kilometric radiation periodicity after equinox
Gurnett, D. A.; Kurth, W. S.; Ye, S. -Y. +2 more
The rotation period of Saturn's magnetosphere was found to vary with time, and changing periodicities were identified in magnetic fields, radio emissions, and charged particles. Here we analyze the varying period of Saturn kilometric radiation (SKR) from 2009 to early 2013, i.e. mainly after Saturn equinox of August 2009. A periodicity analysis is…
Characterizing the Star Formation of the Low-mass Shield Galaxies from Hubble Space Telescope Imaging
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +8 more
The Survey of Hi in Extremely Low-mass Dwarfs is an on-going multi-wavelength program to characterize the gas, star formation, and evolution in gas-rich, very low-mass galaxies that populate the faint end of the galaxy luminosity function. The galaxies were selected from the first ∼10% of the Hi Arecibo Legacy Fast ALFA survey based on their low H…
NuSTAR Observations of the Powerful Radio Galaxy Cygnus A
Hailey, Charles J.; Fabian, Andrew C.; Reynolds, Christopher S. +17 more
We present NuSTAR observations of the powerful radio galaxy Cygnus A, focusing on the central absorbed active galactic nucleus (AGN). Cygnus A is embedded in a cool-core galaxy cluster, and hence we also examine archival XMM-Newton data to facilitate the decomposition of the spectrum into the AGN and intracluster medium components. NuSTAR gives a …
Supernova-driven outflows in NGC 7552: a comparison of H α and UV tracers
Chisholm, John; Calzetti, Daniela; Leitherer, Claus +3 more
We investigate the supernova-driven galactic wind of the barred spiral galaxy NGC 7552, using both ground-based optical nebular emission lines and far-ultraviolet (UV) absorption lines measured with the Hubble Space Telescope Cosmic Origins Spectrograph. We detect broad (∼300 km s-1) blueshifted (-40 km s-1) optical emission …