Search Publications
Evolution of galaxy cluster scaling from XMM-Newton observation of the galaxy clusters at z ⩾ 0.4
Anokhin, S. G.
We present here new XMM-Newton observations of 3 relatively cool clusters at z ≈ 0.4, complemented by archival observations of 3 other clusters at similar redshift. We derived the M- T and R- T relations from the hydrostatic equation using an isothermal temperature distribution.
QSO number counts to B < 24.5 from hubble space telescope WFPC2 images
Anderson, Scott F.; Beck-Winchatz, Bernhard
We have conducted a survey for faint quasars to B < 24.5, z < 2.1 based on archival high-latitude Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) images covering 0.04 deg2 of the sky in three filters spanning 2300 9600 Å. Taking advantage of the superb 0.1″ resolution of WFPC2, we have developed an approach to select …
Spectroscopic observations of coronal waves and coronal mass ejections
Harra, L. K.
It is common to use imaging instruments such as EUV and X-ray imagers and coronagraphs to study large-scale phenomena such as coronal mass ejections and coronal waves. Although high resolution spectroscopy is generally limited to a small field of view, its importance in understanding global phenomena should not be under-estimated. I will review cu…
High resolution X-ray spectroscopy and chemical evolution in elliptical galaxies
Loewenstein, Michael; Davis, David S.
We discuss the elemental composition in the hot ISM of elliptical galaxies derived from new and recent X-ray spectral analysis in the context of new phenomenological models of their chemical evolution. Star formation histories, the IMF, the astrophysics of supernovae, and the nature of galactic winds impact the metal content and relative abundance…
Possibility to detect the cluster emission up to R200 with XMM-Newton data
Sauvageot, J. -L.; Solovyeva, L.; Anokhin, S.
We present the results of analysis XMM-Newton data of galaxy cluster CL0016+16, which enables us to trace X-ray emission and temperature profile up to the virial radius. We obtained similar results using three different backgrounds. We checked the possibility of detection of cluster emission up to the virial radius with XMM-Newton data with hydrod…
Recent theoretical and observational developments in magnetic helicity studies
Démoulin, P.
Magnetic helicity quantifies how the magnetic field is sheared and twisted compared to its lowest energy state (potential field). Such stressed magnetic fields are usually observed in association with flares, eruptive filaments, and coronal mass ejections (CMEs). Magnetic helicity plays a key role in magnetohydrodynamics because it is almost prese…
Orientations of LASCO Halo CMEs and their connection to the flux rope structure of interplanetary CMEs
Yurchyshyn, V.; Lynch, B. J.; Lepping, R. P. +2 more
Coronal mass ejections (CMEs) observed near the Sun via LASCO coronographic imaging are the most important solar drivers of geomagnetic storms. ICMEs, their interplanetary, near-Earth counterparts, can be detected in situ, for example, by the Wind and ACE spacecraft. An ICME usually exhibits a complex structure that very often includes a magnetic …
Measurements of magnetic helicity injected through the solar photosphere
Chae, Jongchul
The amount of magnetic helicity injected into the corona through the photosphere can be measured by inferring the apparent motion of photospheric footpoints of fieldlines from a time series of line-of-sight magnetograms, as originally proposed by [Chae, J., 2001. Observational determination of the rate of magnetic helicity transport through the so…
Temporal variations in solar rotation at the bottom of the convection zone: The current status
Thompson, M. J.; Howe, R.; Komm, R. +4 more
We present the most recent results on the short-period variations in the solar rotation rate near the base of the convection zone. The 1.3-year period which was reported in the early years of solar cycle 23 appears not to persist after 2001, but there are hints of fluctuations at a different period during the declining phase of the cycle.
Coronal mass ejections: Solar cycle aspects
St. Cyr, O. C.; Cremades, Hebe
Research in the area of coronal mass ejections (CMEs) is now mature, since their discovery coincided with the first coronagraph that was flown in space in 1971. However, the continuity of space coronagraphs and similar instruments has allowed the detection and measurement of CMEs over almost three consecutive solar cycles. Their importance in the …