Search Publications
An empirical 3D model of the large-scale coronal structure based on the distribution of Hα filaments on the solar disk
Habbal, S. R.; Morgan, H.
Context: Despite the wealth of solar data currently available, the explicit connection between coronal streamers and features on the solar disk remains unresolved.
Aims: To reproduce the large-scale coronal structure starting from the solar surface, an empirical three-dimensional (3D) model is used to test the assumption that such structure, n…
Mars Express High Resolution Stereo Camera spectrophotometric data: Characteristics and science analysis
Poulet, F.; Bellucci, G.; Jaumann, R. +9 more
The High Resolution Stereo Camera (HRSC) on the Mars Express (MEx) spacecraft in orbit about Mars is delivering images of the Mars surface and atmosphere from its high-inclination, elliptical orbit that are intended to cover most of the Mars surface by the end of the mission. These are acquired in four specific spectral passbands that sample the s…
First detection of a minor merger at z ~ 0.6
Yang, Y.; Neichel, B.; Flores, H. +3 more
Context: Numerical simulations predict that minor mergers are an important channel for the mass assembly of galaxies. However, minor mergers are relatively difficult to detect using imaging, especially at high redshift. While such events are much less violent than major mergers, they can nevertheless leave several features on the kinematical struc…
XMM-Newton X-ray observations of the Wolf-Rayet binary system WR 147
Schmutz, W.; Güdel, M.; Skinner, S. L. +1 more
We present results of an ~20-ks X-ray observation of the Wolf-Rayet (WR) binary system WR 147 obtained with XMM-Newton. Previous studies have shown that this system consists of a nitrogen-type WN8 star plus an OB companion whose winds are interacting to produce a colliding wind shock. X-ray spectra from the pn and MOS detectors confirm the high ex…
The CME Acceleration Problem: Error Estimates in LASCO Coronal Mass Ejection Measurements
Wen, Yayuan; Wang, Jingxiu; Maia, Dalmiro Jorge Filipe
The properties of the coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph Experiment (LASCO) on the Solar and Heliospheric Observatory (SOHO) spacecraft are kept in an online catalog that has been widely used in a series of analyses of individual events and in statistical overviews of CME properties. A subject o…
Multiple Coaxial Rings in the Bipolar Nebula Hubble 12
Kwok, Sun; Hsia, Chih Hao
A series of two-dimensional rings along a common axis aligned with the bipolar lobes is found in the planetary nebula Hb 12. The rings have separations of about 0.3", which can be translated into physical separations of ~1000 AU, or time separations of the order of 50 yr. We suggest that the existence of the rings is a manifestation of the interac…
Magnetic Evolution and Temperature Variation in a Coronal Hole
Zhang, Jun; Wang, Haimin; Wang, Jingxiu +1 more
We have explored the magnetic flux evolution and temperature variation in a coronal hole region, using Big Bear Solar Observatory deep magnetograms and SOHO EIT images observed from 2005 October 10 to 14. For comparison, we also investigated a neighboring quiet region of the Sun. The coronal hole evolved from its mature stage to its disappearance …
Goodness-of-Fit Tests DIFF1 and DIFF2 for Locally Normalized Supernova Spectra
Baron, E.; Branch, David; Danziger, I. J. +3 more
Two quantitative tests DIFF1 and DIFF2 for measuring goodness of fit between two locally normalized supernova spectra are presented. Locally normalized spectra are obtained by dividing a spectrum by the same spectrum smoothed over a wavelength interval relatively large compared to line features, but relatively small compared to continuum features.…
Hinode EUV Imaging Spectrometer Observations of Solar Active Region Dynamics
Warren, Harry P.; Hara, Hirohisa; Ugarte-Urra, Ignacio +3 more
The EUV Imaging Spectrometer (EIS) on the Hinode satellite is capable of measuring emission line center positions for Gaussian line profiles to a fraction of a spectral pixel, resulting in relative solar Doppler-shift measurements with an accuracy of a less than a km s-1 for strong lines. We show an example of the application of that ca…
The age structure of globular cluster systems in early-type galaxies and its dependence on host galaxy properties
Hilker, M.; Kissler-Patig, M.; Hempel, M. +1 more
Aims:We present the results of an optical - near-infrared photometric survey of globular cluster systems in early-type galaxies. Our project aims to study correlations between the age structure of the globular cluster systems and environmental as well as structural parameters of their host galaxies.
Methods: To derive the age structure in glob…