Search Publications
Non-stationarity of the quasi-perpendicular bow shock: comparison between Cluster observations and simulations
Scholer, M.; Soucek, J.; Comişel, H. +1 more
We have performed full particle electromagnetic simulations of a quasi-perpendicular shock. The shock parameters have been chosen to be appropriate for the quasi-perpendicular Earth's bow shock observed by Cluster on 24 January 2001 (Lobzin et al., 2007). We have performed two simulations with different ion to electron mass ratio: run 1 with m
Blazar 3C 454.3 in Outburst and Quiescence during 2005-2007: Two Variable Synchrotron Emission Peaks
Gurwell, Mark A.; Ogle, Patrick M.; Wehrle, Ann E. +1 more
We monitored the flaring blazar 3C 454.3 during 2005 June-July with the Spitzer Infrared Spectrograph (IRS: 15 epochs), Infrared Array Camera (IRAC: 12 epochs), and Multiband Imaging Photometer (MIPS: 2 epochs). We also made Spitzer IRS, IRAC, and MIPS observations from 2006 December to 2007 January when the source was in a low state, the latter s…
The environment and characteristics of low-redshift galaxies detected by the Herschel-ATLAS
Rodighiero, G.; Ivison, R. J.; Clements, D. L. +41 more
We investigate the ultraviolet and optical properties and environment of low-redshift galaxies detected in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) science demonstration data. We use the Sloan Digital Sky Survey seventh release and the Galaxy And Mass Assembly data base to select galaxies with ? mag in the redshift range 0.…
Short-term Evolution of Coronal Hole Boundaries
Gallagher, Peter T.; Krista, Larisza D.; Bloomfield, D. Shaun
The interaction of open and closed field lines at coronal hole (CH) boundaries is widely accepted to be due to interchange magnetic reconnection. To date, it is unclear how the boundaries vary on short timescales and at what velocity this occurs. Here, we describe an automated boundary tracking method used to determine CH boundary displacements on…
Photon dominated regions in NGC 3603. [CI] and mid-J CO line emission
Schieder, R.; Ossenkopf, V.; Bertoldi, F. +32 more
Aims: We aim at deriving the excitation conditions of the interstellar gas as well as the local FUV intensities in the molecular cloud surrounding NGC 3603 to get a coherent picture of how the gas is energized by the central stars.
Methods: The NANTEN2-4 m submillimeter antenna is used to map the [CI] 1-0, 2-1 and CO 4-3, 7-6 lines in a …
Inner disc rearrangement revealed by dramatic brightness variations in the young star PV Cep
Apai, D.; Pál, A.; Ábrahám, P. +11 more
Young Sun-like stars at the beginning of the pre-main-sequence (PMS) evolution are surrounded by accretion discs and remnant protostellar envelopes. Photometric and spectroscopic variations of these stars are driven by interactions of the star with the disc. Time-scales and wavelength dependence of the variability carry information on the physical…
The outer rings of SN 1987A
Lundqvist, P.; Tziamtzis, A.; Gröningsson, P. +1 more
Aims: We investigate the physical properties and structure of the outer rings of SN 1987A to understand their formation and evolution.
Methods: We used low resolution spectroscopy from VLT/FORS1 and high resolution spectra from VLT/UVES to estimate the physical conditions in the outer rings, using nebular analysis for emission lines such…
O+ heating associated with strong wave activity in the high altitude cusp and mantle
Waara, M.; Nilsson, H.; Slapak, R. +3 more
We use the Cluster spacecraft to study three events with intense waves and energetic oxygen ions (O+) in the high altitude cusp and mantle. The ion energies considered are of the order 1000 eV and higher, observed above an altitude of 8 earth radii together with high wave power at the O+ gyrofrequency. We show that heating by…
Optical multiband surface photometry of a sample of Seyfert galaxies. I. Large-scale morphology and local environment analysis of matched Seyfert and inactive galaxy samples
Mihov, B.; Slavcheva-Mihova, L.
Context. Parallel analysis of the large-scale morphology and local environment of matched active and control galaxy samples plays an important role in studies of the fueling of active galactic nuclei.
Aims: We carry out a detailed morphological characterization of a sample of 35 Seyfert galaxies and a matched sample of inactive galaxies in or…
Electron acceleration by an Alfvénic pulse propagating in an auroral plasma cavity
Génot, V.; Mottez, F.
With the help of a 2.5-D particle-in-cell simulation code, we investigate the physics of the acceleration of auroral electrons, through the interaction of an isolated Alfvén wave packet with a plasma density cavity. The cavity is edged by density gradients perpendicular to the magnetic field. We show that a single passing of an isolated wave packe…