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The γ-Ray Detected Narrow-line Seyfert 1 Galaxy 1H 0323+342: Swift Monitoring and Suzaku Spectroscopy
Komossa, S.; Yuan, Weimin; Fuhrmann, L. +3 more
As a radio-loud narrow-line Seyfert 1 galaxy (NLS1) detected by Fermi/LAT in GeV γ-rays, 1H 0323+342 is a remarkable active galactic nucleus showing properties characteristic of both NLS1s and blazars. Here we present results of simultaneous X-ray and UV/optical monitoring observations on 1H 0323+342 taken with the UV/Optical Telescope and X-ray T…
The M31 Near-infrared Period-Luminosity Relation and its Non-linearity for δ Cep Variables with 0.5 <= log (P) <= 1.7
Lee, Chien-Hsiu; Bender, Ralf; Seitz, Stella +7 more
We present the largest M31 near-infrared (F110W (close to J band), F160W (H band)) Cepheid sample so far. The sample consists of 371 Cepheids with photometry obtained from the Hubble Space Telescope PHAT program. The sample of 319 fundamental mode Cepheids, 16 first overtone Cepheids, and 36 type II Cepheids was identified using the median absolut…
The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245
Valtchanov, I.; Esquej, P.; Pérez García, A. M. +14 more
We present subarcsecond resolution infrared (IR) imaging and mid-IR (MIR) spectroscopic observations of the Seyfert 1.9 galaxy NGC 2992, obtained with the Gemini North Telescope and the Gran Telescopio CANARIAS (GTC). The N-band image reveals faint extended emission out to ∼3 kpc, and the polycyclic aromatic hydrocarbon features detected in the GT…
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…