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NGC 2419: a large and extreme second generation in a currently undisturbed cluster
Milone, A. P.; D'Antona, F.; Ventura, P. +6 more
We analyse complementary Hubble Space Telescope and Subaru data for the globular cluster NGC 2419. We make a detailed analysis of the horizontal branch (HB), which is composed of two main groups of stars: the luminous blue HB stars, which extend by evolution into the RR Lyrae and red HB region, and a fainter, extremely blue population. We examine …
Amplitude dependence of frequency sweep rates of whistler mode chorus emissions
Katoh, Yuto; Omura, Yoshiharu
The frequency and amplitude characteristics of chorus emissions are studied by performing electron hybrid code simulations with different initial number densities of energetic electrons. Chorus emissions with rising tones are generated in all simulation runs except for the simulation assuming the lowest number density. The frequency sweep rates of…
A large population of ultra-compact dwarf galaxies in the Hydra I cluster
Hilker, M.; Georgiev, I. Y.; Richtler, T. +3 more
Aims: We performed a large spectroscopic survey of compact, unresolved objects in the core of the Hydra I galaxy cluster (Abell 1060), with the aim of identifying ultra-compact dwarf galaxies (UCDs) and investigating the properties of the globular cluster (GC) system around the central cD galaxy NGC 3311.
Methods: We obtained VIMOS mediu…
X-Ray Spectral Constraints for z ≈ 2 Massive Galaxies: The Identification of Reflection-dominated Active Galactic Nuclei
Daddi, E.; Lehmer, B. D.; Alexander, D. M. +18 more
We use the 4 Ms Chandra Deep Field-South (CDF-S) survey to place direct constraints on the ubiquity of z ≈ 2 heavily obscured active galactic nuclei (AGNs) in K < 22 BzK-selected galaxies. Forty-seven (≈21%) of the 222 BzK-selected galaxies in the central region of the CDF-S are detected at X-ray energies, 11 (≈5%) of which have hard X-ray spec…
Average magnetotail electron and proton pitch angle distributions from Cluster PEACE and CIS observations
Dandouras, I.; Fazakerley, A. N.; Owen, C. J. +2 more
We present results from the first systematic survey of proton and electron pitch angle distributions in the magnetotail, based on Cluster CIS and PEACE data binned by proton plasma β (βp). The proton distributions conform to the canonical picture of magnetotail ions - a boundary layer made up of Earthward streaming and bidirectional fie…
Mars ionosphere: A review of experimental results and modeling studies
Kallio, E.; Haider, S. A.; Mahajan, K. K.
In this paper we review results from atmospheric and ionospheric experiments on the early planetary missions like the Mariners, Mars, and Viking 1 and 2 Orbiters/Landers. We then discuss the new results obtained from the two latest missions, namely, the Mars Global Surveyor (MGS) and Mars Express (MEX). The MGS had three ionospheric and atmospheri…
Integral field spectroscopy of nitrogen overabundant blue compact dwarf galaxies
Kehrig, C.; Pérez-Montero, E.; Vílchez, J. M. +6 more
Context. The oxygen and nitrogen-to-oxygen abundances relation is characterized by a plateau around log(N/O) = -1.6 at metallicities lower than 12+log(O/H) ~ 8.25. However, there is a subset of blue compact dwarf galaxies (BCDs) with unexpectedly high N/O values.
Aims: We want to study the spatial distribution of the physical properties and o…
XMM-Newton X-ray and Ultraviolet Observations of the Fast Nova V2491 Cyg during the Supersoft Source Phase
Ness, J. -U.; Hernanz, M.; Sala, G. +12 more
Two XMM-Newton observations of the fast classical nova V2491 Cyg were carried out in short succession on days 39.93 and 49.62 after discovery, during the supersoft source (SSS) phase, yielding simultaneous X-ray and UV light curves and high-resolution X-ray spectra. The first X-ray light curve is highly variable, showing oscillations with a period…
Galactic cold cores. II. Herschel study of the extended dust emission around the first Planck detections
Abergel, A.; Bernard, J. -P.; Dickinson, C. +15 more
Context. Within the project Galacticcoldcores we are carrying out Herschel photometric observations of cold interstellar clouds detected with the Planck satellite. The three fields observed as part of the Herschel science demonstration phase (SDP) provided the first glimpse into the nature of these sources. The aim of the project is to derive the …
X-Ray Spectroscopy of the High-mass X-Ray Binary Pulsar Centaurus X-3 over Its Binary Orbit
Paul, Biswajit; Naik, Sachindra; Ali, Zulfikar
We present a comprehensive spectral analysis of the high-mass X-ray binary (HMXB) pulsar Centaurus X-3 with the Suzaku observatory covering nearly one orbital period. The light curve shows the presence of extended dips which are rarely seen in HMXBs. These dips are seen up to as high as ~40 keV. The pulsar spectra during the eclipse, out-of-eclips…