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Revealing New Physical Structures in the Supernova Remnant N63A through Chandra Imaging Spectroscopy
Hughes, John P.; Slane, Patrick O.; Warren, Jessica S.
We present Chandra X-ray observations of the supernova remnant (SNR) N63A in the Large Magellanic Cloud (LMC). N63A, one of the brightest LMC remnants, is embedded in an H II region and is probably associated with an OB association. The optical remnant consists of three lobes of emission contained within the approximately 3 times larger X-ray remn…
The Leo I Cloud: Secular Nuclear Evolution of NGC 3379, NGC 3384, and NGC 3368?
Moiseev, A. V.; Chavushyan, V. H.; Sil'chenko, O. K. +2 more
The central regions of the three brightest members of the Leo I galaxy group-NGC 3368, NGC 3379, and NGC 3384-are investigated by means of two-dimensional spectroscopy. In all three galaxies we have found separate circumnuclear stellar and gaseous subsystems-more probably, disks-whose spatial orientations and spins are connected to the spatial ori…
Molecular Gas and the Nuclear Star Cluster in IC 342: Sufficient Inflow for Recurring Star Formation Events?
Meier, David S.; Böker, Torsten; Schinnerer, Eva
We present high spatial resolution (1.2") millimeter-interferometric observations of the 12CO (2-1) line emission in the central 300 pc of the late-type spiral galaxy IC 342. The data, obtained with the Owens Valley Radio Observatory, allow first-time detection of a molecular gas disk that coincides with the luminous young stellar clust…
Some Constraints on the Effects of Age and Metallicity on the Low-Mass X-Ray Binary Formation Rate
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +1 more
We have studied the low-mass X-ray binary (LMXB) populations within and outside globular clusters (GCs) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate-age cluster population of NGC 436…
Hamiltonian canonical formulation of Hall-magnetohydrodynamics: Toward an application to weak turbulence theory
Belmont, G.; Sahraoui, F.; Rezeau, L.
The different levels of description of fluid media [e.g., magnetohydrodynamics (MHD), Hall-magnetohydrodynamics, bi-fluid,…] are commonly known under the form of Newtonian systems of equations. Nevertheless, this form proves to be ill-suited to derive a fully analytical weak turbulence theory of these media, due to the well-known complexity of the…
Evidence for impulsive solar wind plasma penetration through the dayside magnetopause
Lundin, R.; Sauvaud, J. -A.; Balogh, A. +15 more
This paper presents in situ observational evidence from the Cluster Ion Spectrometer (CIS) on Cluster of injected solar wind "plasma clouds" protruding into the day-side high-latitude magnetopause. The plasma clouds, presumably injected by a transient process through the day-side magnetopause, show characteristics implying a generation mechanism d…
A V-Band Survey for Variable Galactic Nuclei in the Hubble Deep Field
Gilliland, Ronald L.; Sarajedini, Vicki L.; Kasm, Christina
We present the results of a two-epoch variability survey in the Hubble Deep Field with the goal of investigating the population of active galactic nuclei (AGNs) to z~=1. The high resolution and stability of the Hubble Space Telescope allow accurate photometry to be obtained within subarcsecond apertures, resulting in the ability to probe much lowe…
The interstellar oxygen-K absorption edge as observed by XMM-Newton. Separation of instrumental and interstellar components
Kaastra, J. S.; de Vries, C. P.; den Herder, J. W. +3 more
High resolution X-ray spectra of the Reflection Grating Spectrometer (RGS) on board the XMM satellite are used to resolve the oxygen K absorption edge. By combining spectra of low and high extinction sources, the observed absorption edge can be split in the true interstellar (ISM) extinction and the instrumental absorption. The detailed ISM edge s…
An Intrinsic Absorption Complex toward RX J1230.8+0115: Geometry and Photoionization Conditions
Charlton, Jane C.; Sembach, Kenneth R.; Ganguly, Rajib +1 more
We present Hubble Space Telescope/Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer spectra of the quasar RX J1230.8+0115 (V=14.4,z=0.117). In addition to Galactic, Virgo, and intervening absorption, this quasar is host to a remarkable intrinsic absorption complex. Four narrow absorption line systems, strong in C IV, …
High Proper Motion Features in the Central Orion Nebula
O'Dell, C. R.; Doi, Takao
The brightest portion of the Orion Nebula has been reimaged with the Hubble Space Telescope in Hα, [N II], and [O III]. Comparison with earlier Wide Field Planetary Camera 2 images going back as much as 8 yr has allowed determination of tangential velocities (proper motions) down to about 10 km s-1 for a variety of sources. Multiple out…