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Sources of electron pitch angle anisotropy in the magnetotail plasma sheet
Fazakerley, A. N.; Owen, C. J.; Taylor, M. G. G. T. +3 more
We survey the properties of electron pitch angle distributions in the magnetotail plasma sheet at a distance between 15 and 19 RE from the Earth, using data from the Plasma Electron and Current Experiment (PEACE) instrument. We limit our survey to those pitch angle distributions measured when the interplanetary magnetic field (IMF) had …
Toward a Removal of Temperature Dependencies from Abundance Determinations: NGC 628
Armus, L.; Hunt, L. K.; Pellegrini, E. +16 more
The metal content of a galaxy, a key property for distinguishing between viable galaxy evolutionary scenarios, strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of extragalactic metallicities is essential in constraining models of chemical enrichment and chemical evolution. Current …
The High-ion Content and Kinematics of Low-redshift Lyman Limit Systems
Tripp, Todd M.; Prochaska, J. Xavier; Davé, Romeel +9 more
We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distributi…
A Direct Stellar Metallicity Determination in the Disk of the Maser Galaxy NGC 4258
Hosek, Matthew W., Jr.; Bresolin, Fabio; Kudritzki, Rolf-Peter +4 more
We present the first direct determination of a stellar metallicity in the spiral galaxy NGC 4258 (D = 7.6 Mpc) based on the quantitative analysis of a low-resolution (~5 Å) Keck Low Resolution Imaging Spectrograph spectrum of a blue supergiant star located in its disk. A determination of stellar metallicity in this galaxy is important for the abso…
The thermal dust emission in N158-N159-N160 (LMC) star-forming complex mapped by Spitzer, Herschel and LABOCA
van Loon, J. Th.; Okumura, K.; Lebouteiller, V. +21 more
Low-metallicity galaxies exhibit different properties of the interstellar medium (ISM) compared to nearby spiral galaxies. Obtaining a resolved inventory of the various gas and dust components of massive star-forming regions and diffuse ISM is necessary to understand how those differences are driven. We present a study of the infrared/submillimetr…
On the nature of the hard X-ray sources SWIFT J1907.3-2050, IGR J12123-5802 and IGR J19552+0044
Mukai, K.; de Martino, D.; Masetti, N. +7 more
The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here, we present the first detailed study of three X-ray-selected CVs, Swift J1907.3-2050, IGR J12123-5802 and IGR J19552+0044 based on XMM-Newton, Suzaku, Swift observations and ground-based optica…
The interaction-driven starburst contribution to the cosmic star formation rate density
Fiore, F.; Santini, P.; Menci, N. +1 more
An increasing amount of observational evidence supports the notion that there are two modes of star formation: a quiescent mode in disk-like galaxies and a starburst mode, which is generally interpreted as driven by merging. Using a semi-analytic model of galaxy formation, we derive the relative contribution to the cosmic star formation rate densi…
A Study of a Failed Coronal Mass Ejection Core Associated with an Asymmetric Filament Eruption
Joshi, Navin Chandra; Filippov, Boris; Srivastava, Abhishek K. +3 more
We present multi-wavelength observations of an asymmetric filament eruption and associated coronal mass ejection (CME) and coronal downflows on 2012 June 17 and 18 from 20:00-05:00 UT. We use SDO/AIA and STEREO-B/SECCHI observations to understand the filament eruption scenario and its kinematics, while LASCO C2 observations are analyzed to study t…
Discovering young stars in the Gum 31 region with infrared observations
Grellmann, R.; Preibisch, T.; Roccatagliata, V. +4 more
Context. The Gum 31 bubble, which contains the stellar cluster NGC 3324, is a poorly studied young region close to the Carina Nebula.
Aims: We are aiming to characterise the young stellar and protostellar population in and around Gum 31 and to investigate the star-formation process in this region.
Methods: We identified candidate young s…
γ Doradus pulsation in two pre-main sequence stars discovered by CoRoT
Chaintreuil, S.; Ryabchikova, T.; Fossati, L. +5 more
Context. Pulsations in pre-main sequence stars have been discovered several times within the last years. But nearly all of these pulsators are of δ Scuti-type. γ Doradus-type pulsation in young stars has been predicted by theory, but lack observational evidence.
Aims: We present the investigation of variability caused by rotation and (γ Dorad…