Search Publications
Chandra X-Ray Sources in the Collapsed-Core Globular Cluster M30 (NGC 7099)
Heinke, Craig O.; Cohn, Haldan N.; Lugger, Phyllis M. +2 more
We report the detection of six discrete, low-luminosity (LX<1033 ergs s-1) X-ray sources, located within 12" of the center of the collapsed-core globular cluster M30 (NGC 7099), and a total of 13 sources within the half-mass radius, from a 50 ks Chandra ACIS-S exposure. Three sources lie within the very small up…
X-Ray Luminosity Functions of Normal Galaxies in the Great Observatories Origins Deep Survey
Mobasher, Bahram; Bauer, Franz; Norman, Colin +2 more
We present soft (0.5-2 keV) X-ray luminosity functions (XLFs) in the Great Observatories Origins Deep Survey (GOODS) fields derived for galaxies at z~0.25 and 0.75. SED fitting was used to estimate photometric redshifts and separate galaxy types, resulting in a sample of 40 early-type galaxies and 46 late-type galaxies. We estimate k-corrections f…
An XMM-Newton Observation of the Local Bubble Using a Shadowing Filament in the Southern Galactic Hemisphere
Kuntz, K. D.; Henley, David B.; Shelton, Robin L.
We present an analysis of the X-ray spectrum of the Local Bubble, obtained by simultaneously analyzing spectra from two XMM-Newton pointings on and off an absorbing filament in the southern Galactic hemisphere (b~-45deg). We use the difference in the Galactic column density in these two directions to deduce the contributions of the unab…
Flow Field Evolution of a Decaying Sunspot
Liu, Chang; Denker, Carsten; Wang, Haimin +3 more
We study the evolution of the flows and horizontal proper motions in and around a decaying follower sunspot based on time sequences of two-dimensional spectroscopic observations in the visible and white-light imaging data obtained over 6 days from 2005 June 7 to 12. During this time period the sunspot decayed gradually to a pore. The spectroscopic…
Monte Carlo Simulation of Directivity of Interplanetary Radio Bursts
MacDowall, R. J.; Kaiser, M. L.; Thejappa, G.
We have developed a Monte Carlo simulation code to study the effects of refraction due to spatial variation of the solar wind density and scattering due to random density fluctuations on directivities, time profiles, and sizes and positions of the apparent sources of the interplanetary type II and type III radio bursts excited at the fundamental (…
A Streamer Ejection with Reconnection Close to the Sun
Warren, H. P.; Sheeley, N. R., Jr.; Wang, Y. -M.
We previously described coronal events that expand gradually outward over an interval of 1-2 days and then suddenly tear apart in the coronagraph's 2-6 Rsolar field of view to form an outgoing flux rope and an inward system of collapsing loops. Now, we combine LASCO white-light images of the outer corona with spectrally resolved EIT ima…
Deviations from He I Case B Recombination Theory and Extinction Corrections in the Orion Nebula
Martin, P. G.; Blagrave, K. P. M.; Dufour, R. J. +4 more
We are engaged in a comprehensive program to find reliable elemental abundances in and probe the physical structure of the Orion Nebula, the brightest and best-resolved H II region. In the course of developing a robust extinction correction covering our optical and UV FOS and STIS observations, we examined the decrement within various series of He…
The Width of a Solar Coronal Mass Ejection and the Source of the Driving Magnetic Explosion: A Test of the Standard Scenario for CME Production
Moore, Ronald L.; Sterling, Alphonse C.; Suess, Steven T.
We show that the strength (BFlare) of the magnetic field in the area covered by the flare arcade following a CME-producing ejective solar eruption can be estimated from the final angular width (Final θCME) of the CME in the outer corona and the final angular width (θFlare) of the flare arcade: BFlare~1.4…
Calibration of Seismic Signatures of Active Regions on the Far Side of the Sun
Hill, F.; Lindsey, C.; González Hernández, I.
Synoptic maps of the far hemisphere of the Sun calculated from seismic holography have proven to be very reliable in localizing large active regions before they rotate onto the visible hemisphere. We show here the first results toward a calibration of the far-side signatures of active regions in terms of active region size and magnetic field stren…
Phase-resolved Spectroscopy of the Vela Pulsar with XMM-Newton
Caraveo, P. A.; De Luca, A.; Manzali, A.
The ~104 yr old Vela Pulsar represents the bridge between the young Crab-like and the middle-aged rotation-powered pulsars. Its multiwavelength behavior is due to the superposition of different spectral components. We take advantage of the unprecedented harvest of photons collected by XMM-Newton to assess the Vela Pulsar spectral shape …