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An Extreme Solar Event of 20 January 2005: Properties of the Flare and the Origin of Energetic Particles
Kurt, V. G.; Grechnev, V. V.; Chertok, I. M. +9 more
The famous extreme solar and particle event of 20 January 2005 is analyzed from two perspectives. Firstly, using multi-spectral data, we study temporal, spectral, and spatial features of the main phase of the flare, when the strongest emissions from microwaves up to 200 MeV gamma-rays were observed. Secondly, we relate our results to a long-standi…
Solar wind vs magnetosheath turbulence and Alfvén vortices
Alexandrova, O.
In this paper we give firstly a broad review of the space plasma turbulence around the ion characteristic space and temporal scales within two natural laboratories, the solar wind and the Earth magnetosheath. In both regions power law spectra of magnetic fluctuations are observed. In both regions these spectra have a break in the vicinity of the i…
A synchrotron self-Compton scenario for the very high energy γ-ray emission of the radiogalaxy M 87. Unifying the TeV emission of blazars and other AGNs?
Boisson, C.; Sol, H.; Katarzyński, K. +1 more
Context: M 87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Čerenkov telescopes, we can now probe the variability in the γ-ray flux on small timescales, thus putting strong constraints on the size of the emitting zone. The large scale jet of M 87 is misaligned wit…
Mid-Infrared Spectroscopy of Lensed Galaxies at 1 < z < 3: The Nature of Sources Near the MIPS Confusion Limit
Kneib, J. -P.; Rigby, J. R.; Papovich, C. +10 more
We present Spitzer IRS mid-infrared spectra for 15 gravitationally lensed, 24 µm-selected galaxies, and combine the results with four additional very faint galaxies with IRS spectra in the literature. The median intrinsic 24 µm flux density of the sample is 130 µJy, enabling a systematic survey of the spectral properties of the v…
Hinode EUV spectroscopic observations of coronal oscillations
Erdélyi, R.; Taroyan, Y.
Context: Waves offer a unique opportunity to understand and diagnose the properties of the solar coronal plasma.
Aims: Hinode/EIS observations are analysed to detect wave and oscillatory motions in the solar corona.
Methods: The EIS observations were carried out using a selection of EUV lines. Hinode/XRT images are taken concurrently.
…
Discovery of a bipolar X-ray jet from the T Tauri star DG Tauri
Audard, M.; Güdel, M.; Briggs, K. R. +2 more
Aims:We have obtained and analyzed Chandra ACIS-S observations of the strongly accreting classical T Tauri star DG Tau. Our principal goals are to map the immediate environment of the star to characterize possible extended X-rays formed in the jet, and to re-visit the anomalous, doubly absorbed X-ray spectrum of DG Tau itself.
Methods: We comb…
Another Nonsegregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419
Dalessandro, E.; Bellazzini, M.; Ferraro, F. R. +3 more
We have used a combination of ACS HST high-resolution and wide-field Subaru data in order to study the blue straggler star (BSS) population over the entire extension of the remote Galactic globular cluster NGC 2419. The BSS population presented here is among the largest ever observed in any stellar system, with more than 230 BSSs in the brightest …
An Accurate Age Determination for the Small Magellanic Cloud Star Cluster NGC 121 with the Hubble Space Telescope/Advanced Camera for Surveys
Grebel, Eva K.; Gallagher, John S., III; Sabbi, Elena +8 more
As the first paper of a series devoted to study the old stellar population in clusters and fields in the Small Magellanic Cloud (SMC), we present deep observations of NGC 121 in the F555W and F814W filters, obtained with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The resulting color-magnitude diagram reaches ~3.5 mag belo…
Large Einstein radii: a problem for ΛCDM
Barkana, Rennan; Broadhurst, Tom J.
The Einstein radius of a cluster provides a relatively model-independent measure of the mass density of a cluster within a projected radius of ~150kpc, large enough to be relatively unaffected by gas physics. We show that the observed Einstein radii of four well-studied massive clusters, for which reliable virial masses are measured, lie well beyo…
Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z ~ 2. III. Far-IR to Radio Properties and Optical Spectral Diagnostics
Choi, Philip; Helou, George; Lutz, Dieter +7 more
We present the FIR, millimeter, and radio photometry and optical and NIR spectroscopy of a sample of 48 z ~ 1-3 Spitzer-selected ULIRGs with IRS MIR spectra. Our goals are to compute their bolometric emission and to determine both the presence and relative strength of their AGN and starburst components. We find that strong-PAH sources tend to have…