Search Publications
The Role of Transient Brightenings in Heating the Solar Corona
Warren, Harry P.; Ugarte-Urra, Ignacio; Brooks, David H.
Nanoflare reconnection events have been proposed as a mechanism for heating the corona. Parker's original suggestion was that frequent reconnection events occur in coronal loops due to the braiding of the magnetic field. Many observational studies, however, have focused on the properties of isolated transient brightenings unassociated with loops, …
Polar Plume Brightening During the 2006 March 29 Total Eclipse
Rušin, V.; Druckmüller, M.; Minarovjech, M. +8 more
We discuss a remarkable brightening in a polar plume, as inferred from unique coordinated observations of the white-light corona during the total eclipse of the Sun of 2006 March 29. The polar plume (also known as a polar ray, with distinctions that we discuss) was observed at the positional angle of 9° the velocity at which the brightening propag…
Hubble Space Telescope Search for M Subdwarf Binaries
Gizis, John E.; Riaz, Basmah; Samaddar, Debasmita
We present HST ACS observations of 19 nearby M subdwarfs in a search for binary systems. Other than the wide common proper-motion pair LHS 2140/2139, none of our sdM and esdM targets are found to be binaries. Our survey is sensitive to equal-luminosity companions at close (2-8 AU) separations, while substellar secondaries could have been detected …
A Simulation of a Coronal Mass Ejection Propagation and Shock Evolution in the Lower Solar Corona
Gombosi, T. I.; Cohen, O.; Opher, M. +2 more
We present a detailed simulation of the evolution of a moderately slow coronal mass ejection (CME; 800 km s-1 at 5 R⊙, where R⊙ is solar radii) in the lower solar corona (2-5 R⊙). The configuration of the Sun's magnetic field is based on the MDI data for the solar surface during Carrington rotation 1922.…
The X-Ray Properties of Moderate-Redshift Galaxy Groups Selected by Association with Gravitational Lenses
McKean, J. P.; Auger, M. W.; Mulchaey, J. S. +5 more
We present results from a systematic investigation of the X-ray properties of a sample of moderate-redshift (0.3 < z < 0.6) galaxy groups. These groups were selected not by traditional X-ray or optical search methods, but rather by an association, either physical or along the line of sight, with a strong gravitational lens. We calculate the …
A Transient Black Hole Low-Mass X-Ray Binary Candidate in Centaurus A
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +14 more
We report the discovery of a bright transient X-ray source, CXOU J132518.2-430304, toward Centaurus A (Cen A) using six new Chandra X-Ray Observatory observations in 2007 March-May. Between 2003 and 2007, its flux has increased by a factor of >770. The source is likely a low-mass X-ray binary in Cen A with unabsorbed 0.3-10 keV band luminositie…
The Nature of the Ultraluminous Oxygen-Rich Supernova Remnant in NGC 4449
Milisavljevic, Dan; Fesen, Robert A.
Optical images and spectra, both ground based and taken by Hubble Space Telescope (HST), of the young, luminous O-rich supernova remnant in the irregular galaxy NGC 4449 are presented. HST images of the remnant and its local region were obtained with the ACS/WFC using filters F435W, F555W, F814W (B, V, and I, respectively), F502N ([O III]), F658N …
The Fundamental Plane of QSOs and the Relationship between Host and Nucleus
Turnshek, David A.; Casertano, Stefano; Hamilton, Timothy S.
We present results from an archival study of 70 medium-redshift QSOs observed with HST's WFPC2. The QSOs have magnitudes MV <= - 23 (total nuclear plus host light) and redshifts 0.06 <= z <= 0.46. The aim of the present study is to investigate the connections between the nuclear and host properties of QSOs, using high-resolutio…
Isotopic Ratios in Titan's Atmosphere from Cassini CIRS Limb Sounding: CO2 at Low and Midlatitudes
Irwin, P. G. J.; Teanby, N. A.; Flasar, F. M. +8 more
This Letter reports on a search for infrared emissions of isotopologues of CO2 in the atmosphere of Titan using spectral data recorded by the Cassini Composite Infrared Spectrometer (CIRS). We have made a successful 6.5 σ detection of 13CO2 at a fraction CO2/13CO2 = 84 ± 17, consist…
Probing Elemental Abundances in SNR 1987A using XMM-Newton
Haberl, Frank; Heng, Kevin; Hasinger, Günther +1 more
We report on the latest (2007 January) observations of supernova remnant (SNR) 1987A from the XMM-Newton mission. Since the 2003 May observations of Haberl et al., 11 emission lines have experienced increases in flux by factors ~3-10, with the 775 eV line of O VIII showing the greatest increase; we have observed six lines of Fe XVII and Fe XVIII p…