Search Publications
Red giant clump in the Tycho-2 catalogue
Gontcharov, G. A.
The Tycho-2 proper motions and Tycho-2 and 2MASS photometry are used to select 97348 red giant clump (RGC) stars. The interstellar extinction and photometric distance are calculated for each of the stars. The selected stars are shown to form a selection-unbiased sample of RGC stars within about 350 pc of the Sun with the addition of more distant s…
Mid-Infrared Spectra of High-Redshift (z > 2) Radio Galaxies
Stern, D.; Fazio, G. G.; Seymour, N. +8 more
We present the first mid-infrared Spitzer/Infrared Spectrograph (IRS) observations of powerful radio galaxies at z > 2. These radio galaxies, 4C +23.56 (z = 2.48) and 6C J1908+7220 (z = 3.53), both show strong mid-infrared continua, but with 6C J1908+7220 also showing strong PAH emission at rest-frame 6.2 and 7.7 µm. In 4C +23.56 we see n…
An X-ray and optical study of the ultracompact X-ray binary A 1246-58
Verbunt, F.; in't Zand, J. J. M.; Méndez, M. +4 more
Results are discussed of an X-ray and optical observation campaign of the low-mass X-ray binary A 1246-58 performed with instruments on Satellite per Astronomia X (“BeppoSAX”), the Rossi X-ray Timing Explorer (RXTE), the X-ray Multi-mirror Mission (“XMM-Newton”), the Swift mission, and the Very Large Telescope. Spectra and flux time histories are …
Electron-impact excitation of Be-like Mg
Del Zanna, G.; Badnell, N. R.; Rozum, I.
We present an R-matrix calculation of electron-impact excitation of Be-like Mg. The calculation is similar to that one presented for Be-like Fe by Chidichimo et al. (2005, A&A, 430, 331), and was done with the intermediate-coupling frame transformation method and including a total of 98 fine-structure levels, up to n=4. We find significant dif…
Short-Period Fluctuations in Coronal Mass Ejection Activity during Solar Cycle 23
Lara, Alejandro; Borgazzi, Andrea; Mendes, Odim, Jr. +2 more
We have constructed a time series of the number of coronal mass ejections (CMEs) observed by SOHO/LASCO during solar cycle 23. Using spectral analysis techniques (the maximum entropy method and wavelet analysis) we found short-period (< one year) semiperiodic activity. Among others, we found interesting periodicities at 193, 36, 28, and 25 days…
Implications from Ithaca Chasma for the thermal and orbital history of Tethys
Nimmo, F.; Chen, E. M. A.
Flexural modeling of Ithaca Chasma on Tethys suggests that the elastic thickness and the surface heat flux were 5-7 km and 18-30 mW/m2 respectively, when the feature formed (~4 Gyr B.P.). Tidal heating is a plausible heat source, suggesting that Tethys' eccentricity was higher in the past. Depending on Tethys' internal structure, eccent…
A Study of Surges: II. On the Relationship between Chromospheric Surges and Coronal Mass Ejections
Liu, Yu
Liu et al. (Astrophys. J.628, 1056, 2005a) described one surge - coronal mass ejection (CME) event showing a close relationship between solar chromospheric surge ejection and CME that had not been noted before. In this work, large Hα surges (>72 Mm, or 100 arcsec) are studied. Eight of these were associated with CMEs. According to their distinc…
Swift observations of IBL and LBL objects
Tosti, G.; Giommi, P.; Nesci, R. +5 more
Context: BL Lacs are an enigmatic class of active galactic nuclei (AGNs), characterized by the non-thermal continuum typically attributed to synchrotron and inverse Compton emission. Depending on the frequency location of the maxima of these components, they are subdivided into three subclasses LBLs, IBLs, and HBLs. We present the results of a set…
Finding Galaxy Groups in Photometric-Redshift Space: The Probability Friends-of-Friends Algorithm
Yee, H. K. C.; Li, I. H.
We present a structure-finding algorithm designed to identify galaxy groups in photometric-redshift data sets: the probability friends-of-friends (pFoF) algorithm. This algorithm is derived by combining the FoF algorithm in the transverse direction and the photometric-redshift probability densities in the radial dimension. The innovative character…
Observations of atmospheric water vapor above the Tharsis volcanoes on Mars with the OMEGA/MEx imaging spectrometer
Maltagliati, Luca; Bibring, Jean-Pierre; Langevin, Yves +6 more
The OMEGA imaging spectrometer onboard the Mars Express spacecraft is particularly well suited to study in detail specific regions of Mars, thanks to its high spatial resolution and its high signal-to-noise ratio. We investigate the behavior of atmospheric water vapor over the four big volcanoes located on the Tharsis plateau (Olympus, Ascraeus, P…