Search Publications
Missions
Journals
Publication Years
XMM-Newton Observation of Solar Wind Charge Exchange Emission
Kuntz, K. D.; Snowden, S. L.; Collier, M. R.
We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by probable C VI lines at 0.37 and 0.46 keV, an O VII line at 0.56 keV, O VIII lines at 0.65 and ~0.8 keV, Ne IX lines at ~0.92 keV, and Mg XI lines at ~1.35 keV. This spectrum is consistent with that expected from charge exchange em…
Emergence of magnetic flux from the convection zone into the corona
O'Shea, E.; Galsgaard, K.; Moreno-Insertis, F. +2 more
Numerical experiments of the emergence of magnetic flux from the uppermost layers of the solar interior to the photosphere and its further eruption into the low atmosphere and corona are carried out. We use idealized models for the initial stratification and magnetic field distribution below the photosphere similar to those used for multidimension…
XMM-Newton EPIC observations of 21 low-redshift PG quasars
Porquet, D.; Reeves, J. N.; Brinkmann, W. +1 more
We present an X-ray spectral analysis of 21 low redshift quasars observed with XMM-Newton EPIC. All the sources are Palomar Green quasars with redshifts between 0.05 and 0.4 and have low Galactic absorption along the line-of-sight. A large majority of quasars in the sample (19/21) exhibit a significant soft excess below ∼1-1.5 keV, whilst two obje…
Perennial water ice identified in the south polar cap of Mars
Sotin, C.; Drossart, Pierre; Forni, O. +39 more
The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet. From the early mapping observation of the permanent ice caps on the martian poles, the northern cap was believed to be mainly composed of water ice, whereas the southern …
Energy partition in two solar flare/CME events
Kucharek, H.; Mewaldt, R. A.; Mason, G. M. +12 more
Using coordinated observations from instruments on the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO), and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), we have evaluated the energetics of two well-observed flare/CME events on 21 April 2002 and 23 July 2002. For each event, we have estimated the en…
2MASS NIR photometry for 693 candidate globular clusters in M 31 and the Revised Bologna Catalogue
Bellazzini, M.; Galleti, S.; Federici, L. +2 more
We have identified in the 2MASS database 693 known and candidate globular clusters in M 31. The 2MASS J, H, K magnitudes of these objects have been transformed to the same homogeneous photometric system of existing near infrared photometry of M 31 globulars, finally yielding J, H, K integrated photometry for 279 confirmed M 31 clusters, 406 unconf…
The binary progenitor of Tycho Brahe's 1572 supernova
Filippenko, Alexei V.; Foley, Ryan J.; Ibata, Rodrigo +8 more
The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion. Unless the companion star is…
Automated recognition of coronal mass ejections (CMEs) in near-real-time data
Berghmans, D.; Robbrecht, E.
This paper presents a new method and first applications of software that we have developed to autonomously detect CMEs in image sequences from LASCO (Large Angle Spectrometric Coronagraph). The crux of the software is the detection of CMEs as bright ridges in (time, height) maps using the Hough transform. The next step employs clustering and morph…
Bar Evolution over the Last 8 Billion Years: A Constant Fraction of Strong Bars in the GEMS Survey
Bell, Eric F.; Ravindranath, Swara; Somerville, Rachel S. +25 more
One-third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question of how bars evolve over cosmological times has yet to be resolved, and even the frequency of bars at intermediate redshifts remains controversial. We investigate the frequency of bars out to z ~ 1 drawing on a…
The host of GRB 030323 at z=3.372: A very high column density DLA system with a low metallicity
Pian, E.; Palazzi, E.; Kouveliotou, C. +29 more
We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lyα (DLA) absorption and low- and high-ionization lines at a redshift z=3.3718±0.0005. The inferred neutral hydrogen column density, log N(H I)=21.90±0.07, is larger than any (GRB- or QSO-) DLA H I column density inferred directly from L…