Using extensive ground-based spectroscopy, we isolate the E+A population in three intermediate redshift clusters ($z=0.33$, 0.58 and 0.83) and study their physical properties using HST/WFPC2 imaging. Our analysis includes galaxy colors, luminosities, Hubble types, and quantitative structural parameters as well as measured and estimated internal velocity dispersions. We find E+A galaxies make up a non-negligible fraction ($\sim7-13\%$) of cluster members at these redshifts, and their diverse nature indicates a heterogeneous parent population. From their velocity dispersions and half-light radii, we infer that the descendants of the E+A's in our highest redshift clusters are massive early-type galaxies, and we estimate that $\gtrsim30\%$ of the E-S0 members have undergone an E+A phase. We also find the characteristic E+A mass decreases with decreasing redshift; this is similar to the decrease in luminosity of rapidly star-forming field galaxies since $z\sim1$, i.e. galaxy “down-sizing”.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Coronal mass ejections (CMEs) are sources of the strongest geomagnetic disturbances. From sunspot minimum to sunspot maximum, the intensity of storms associated with CMEs increases but the degree of association decreases. We divide the CMEs in the last solar cycle (1996–2002) into magnetic clouds (MCs)and CMEs which are not magnetic clouds. MCs are much more geoeffective than non-MC CMEs, and the portion of CMEs which are MCs is maximum in sunspot minimum and minimum at sunspot maximum, corresponding to the net helicity transferred from the solar interior into the corona. The smaller portion of the more geoeffective MCs is the explanation of the smaller degree of association of CMEs with geomagnetic disturbances in sunspot maximum.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The properties of the magnetic field in the coronal holes (CH) were considered during 1996-2002. The daily observations from the Kitt Peak observatory in the line HeI 10830Å were compiled. The measurement of the magnetic fields in the CH was carried out by comparing the data obtained from the Kitt Peak telescope and the magnetograms of SOHO/MDI. The dependence between the brightness of CH from intensity of the magnetic field and distributions of CH depending from the magnetic field and latitude were presented for minimum and maximum of the cycle. The latitude and the unipolarity degree of the magnetic field that influence on the brightness of the CH were examined. It was shown that the average magnetic field was 1-2G, the unipolarity degree of the magnetic field was 0.1-0.3 and brightness of the coronal holes increases with the average magnetic field. The latitude-time distributions of CH for different polarity were obtained.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The main observable components of coronal mass ejections (CMEs) are the core, cavity and the frontal structure (FS), which is the leading edge of the visible CME. The core of a CME is associated with an eruptive filament whose motion can be followed just from the solar surface. As a rule, the FS is visible in scattered white light (SOHO/LASCO) far from the CME origination site. In few cases in near-the-limb events, the FS was detected closer to the solar surface. However, it appears not possible to detect any manifestations of the FS in a reasonable proximity of the pre-eruptive filament localized on the sun far from the limb. The identification of the FS remains unclear. We propose a method to estimate parameters of the initial volume of a CME based on the comparison of measured height-time plots of its structural components with a self-similar solution of MHD equations describing the expansion of a CME.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

More than 40 gradual SEPs have been observed by GOES and SOHO from 2001 to 2003. During 12 SEPs of all these events, energetic electron flux enhancements with energies from 38 keV to 337 keV were observed by RAPID onboard Cluster spacecraft. During these 12 events the variation of the energetic electron flux measured by RAPID/Cluster was closely associated to the variation of the solar energetic proton flux. The observed energetic electron flux was independent on the location of Cluster in the magnetosphere and the background level of magnetospheric electrons (even when the Cluster spacecraft was crossing the magnetopause, the plasma sheet and the low latitude boundary layer). The similar variation of the enhancement of energetic electron flux has also been observed by POLAR and Geotail in some of these events. In some of these events, the electron measurement of RAPID/Cluster will not be contaminated by the SEP protons.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present some preliminary results from an on-going study of the evolution of stellar populations in rich clusters of galaxies. Our baseline sample contains core line-strength measurements from 183 galaxies with $b_{\rm J} \le 19.5$ from four clusters with $\bar{z}\sim0.04$, against which observations of higher-redshift clusters can be compared. Using predictions from stellar population models to compare with our measured line strengths we can derive relative luminosity-weighted mean ages and metallicities for the stellar populations in each of our clusters. It must be stressed that these ages and metallicities are only accurate when used in a relative sense as the stellar population models, due to differing abundance ratios used in the models compared to those observed in elliptical galaxies, provide inaccurate absolute ages and metallicities. We also investigate the ${\rm Mg}b^\prime$-$\sigma_0$ and H$\beta_G^\prime$-$\sigma_0$ scaling relations. We find that ${\rm Mg}b^\prime$ is correlated with $\sigma_0$, the likely explanation being that larger galaxies are better at retaining their heavier elements due to their larger potentials. ${\rm H}\beta_G^\prime$, on the other hand, we find to be anti-correlated with $\sigma_0$. This result implies that the stellar populations in larger galaxies are older than in smaller galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Michigan Catalogue (Vol. I – V) is an excellent database to study the distribution of CP2 stars in the galactic field in the Southern hemisphere. A cross-check with the Bidelman-Catalogue (1973) and the “Catalogue Général des Étoiles Ap et Am” (Renson 1991) shows that in the Michigan Catalogue 3.6% of all stars in the relevant spectral region are CP2 stars. Any discrepant classified stars could be verified photometrically in the $\Delta a$-system. The distribution of CP2 stars does not show any particular preferred region in the Southern hemisphere. The ages of these stars and an evolutionary dependence of the CP2 effect was another important question. We conclude that the CP2 stars occupy the full Main Sequence band.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The abundance of α-process elements such as magnesium and carbon relative to iron, measured from the broad emission lines of QSOs, can serve as a diagnostic of the star formation and chemical enrichment histories of their host galaxies. We investigate the relationship between Fe/Mg and Fe/C abundance ratios and the resulting Fe II / Mg II λ2800 and Fe II / 1900Å-blend flux ratios, both of which have been measured in QSOs out to z≈6. Using a galactic chemical evolution model based on a starburst in a giant elliptical galaxy, we find that these flux ratios are good tracers of the chemical enrichment of the nuclei. However, the values of these ratios measured in objects at z≈6 suggest that iron enrichment has occurred more rapidly in these objects than predicted by the assumed elliptical starburst model, assuming currently favored cosmologies. This in turn suggests that refinements to the galactic chemical evolution models are needed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The parameter-free model of diffusion in the atmospheres of HgMn stars (Michaud 1986, Michaud et al. 1979) predicts that helium should sink below the $\hbox{He\,{\sc ii}}$ ionization zone that the diffusion of other elements may take place, and that all HgMn stars should have deficits of helium in their photospheres, with a minimum deficit of 0.3 dex. In this study, the Smith & Dworetsky (1993) sample of HgMn stars and normal comparison stars is examined, and the helium abundances determined by spectrum synthesis using échelle spectra taken at Lick Observatory and the AAT. The prediction is confirmed. All HgMn stars are deficient in He by as much as 1.5 dex. Also, two HgMn stars, HR 7361 and HR 7664, show clear evidence of helium stratification.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We studied the relationship between successive coronal mass ejections (CMEs) and a long-lived geomagnetic storm (LLGMS) by examining the 1998 May 4 event. Five successive CMEs from the same active region and four interplanetary shocks were found to be associated with this LLGMS. We investigated the effect of successive and interacting CMEs on the LLGMS.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The spectra of the MnI 539.47 nm spectral line were observed in three different sunspots of the NOAA 0431 active region. Perpendicularly to the dispersion axis, the spectra were divided into several strips that covers the quiet photosphere, penumbra and the umbra of the appropriate sunspot. The manganese spectral line parameters variation along the spectrograph slit were determined and analyzed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have investigated the stellar kinematics of two brightest cluster galaxies (BCGs) to large distances from the cluster centre. In both galaxies, the velocity dispersion rises with radius. Orbital anisotropy is ruled out as the cause and we conclude that the kinematics in the outer parts of BCGs are dark matter dominated. This result contrasts with the current problem for intermediate luminosity ellipticals, which appear to have less dark matter than predicted by CDM. Combining the present results with our previous work, the fraction of BCGs with outwardly rising dispersions ($\sim60\%$) is much higher than that found previously ($\sim7\%$) from the inner parts of BCGs. We argue that this phenomenon may be more common than previously thought. The agreement with radial trends expected for a smooth galaxy/cluster transition, and the lack of dependence on cD/BCG dominance and cluster environment, suggest that the outwardly rising dispersion is a genuine response of the stars to the underlying cluster potential. There is evidence that BCG in Abell 2063 is not at the centre of the cluster potential.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results of a self-consistent model of the spectral energy distribution (SED) of starburst galaxies. Two parameters control the IR SED, the mean pressure in the ISM and the destruction timescale of molecular clouds. Adding a simplified AGN spectrum provides mixing lines on IRAS color : color diagrams. This reproduces the observed colors of both AGNs and starbursts.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Figure 1 shows the horizontal velocity pattern of photospheric features in the main part of active region NOAA 9077 on 2000 July 12 – 15, where the horizontal velocity vectors are overlapped by white light images (left) and contours represent $G=-2{\bf U}\cdot {\bf A_p}B_n$ (injective rate of magnetic helicity) inferred from the horizontal velocity vectors and longitudinal magnetic field (right). The black (white) contours with white (black) areas mark the positive (negative) change rate of magnetic helicity of $\pm$5, 20, 50, 100, 180, 300 ($\times 10^{13}G^2m^2s^{-1}$). The arrows overlapped by $G$ mark the transverse magnetic field.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Several Halo CMEs hit the Earth in the second half of July 2004. They were produced by the very large complex active region NOAA 652 (Yousef et al. 2005). For CME details consult the web (ftp://lasco6.nascom.nasa.gov/pub/lasco/status/LASCO_CME_List_004).

We focus on the 26$^{th}$ -27$^{th}$ of July CME hit. This CME was associated with the long-duration M1 flare at 25/15:14. It made a very fast Sun to Earth transit-just over 31 hours (SGAS 27 July 2004). A greater than 10 MeV proton event began at 25/18:55. Solar wind speed remained elevated from 500 to over 700 km/s. A Severe Geomagnetic storm was observed and the aurora was seen as far as California.

A strong shock impacted the ACE spacecraft at 26/22:28. A sudden impulse (SI) of 96 nT was observed on the Boulder magnetometer at 22:51. The IMF Bz component was turned negative (−18 nT). Generally speaking, according to de Pater and Lissauer (2001), since a strong CME disturbance in the solar wind is usually preceded by an interplanetary shock followed by an enhanced density and velocity, the field strength first increases when the disturbance hits the magnetosphere, inducing an increase in the ring current. Several hours(up to over 25 hrs) the field strength Dst decreases dramatically during the storm main phase which typically lasts for a day The main phase is caused by an increase in the ring current, resulting from an enhanced particle flow towards the Earth. It is well known that geomagnetic storms tend to occur when IMF is directed southward. Magnetic reconnection occurs between the negative IMF and the magnetosphere thus opens the field lines with one end connected to the Earth (Dungey 1963). This magnetic reconnection allowed the protons and electrons to leak in. The proton and electron flux maximums occurred around the time of geomagnetic storm commencement which lasted for about 27 h (fig. 1). This is in agreement with the statement of Robinson (2003) that large numbers of energetic protons are constrained to occupy the region around the IP shock. The IMF Bz component dropped to −20 nT on 27 of July at 12:00 UT as measured by ACE satellite while Kp reached a maximum of 9 around 15:00 UT at the storm maximum as seen in fig. 2.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

As part of a larger program to study spatially resolved jet / interstellar medium interactions in nearby Seyfert galaxies, we have obtained high spatial resolution spectrographic observations of the central regions of M 51 and its extra-nuclear cloud (XNC, Ford et al. 1985), using STIS on-board the Hubble Space Telescope (HST). In this paper, we present very preliminary results from these observations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Ellipticals in very low density environments are extremely rare but hold important clues about galaxy formation and evolution. We present results of an investigation of their internal dynamics. We observe a dichotomy in kinematic properties similar to that in normal ellipticals. We compare the positions of isolated ellipticals with respect to the Fundamental Plane of normal ellipticals and find that they fall onto it, with the exception of NGC 2865. This shows that isolated ellipticals are structurally similar to normal ellipticals, and do not have very young ages, although some have signs of past mergers or interactions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using high-dispersion spectral observations of HD 101065 (Przybylski's star) we have identified the lines of heavy radioactive elements with atomic numbers from 84 to 99 in the spectrum of the star. We found the lines of all these elements except At (Z=85) and Fr (Z=87). We try to explain a presence of such heavy species in the atmosphere of this star as a result of radioactive decay of Th and U nuclei and neutron capture process producing some transuranium isotopes. The necessary conditions for these processes to work may appear due to atomic diffusion and favorable accumulation of the thorium and uranium nuclei in the upper of the PS atmosphere.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

As young stars evolve from the time of their formation onto the main sequence, they lose mass in a variety of ways. At the very earliest stages, mass loss may be in the form of jets associated with accretion from a surrounding disk. These cool jets carve out the surrounding gas and their changes over time may indicate changes in the star-formation process. At later stages, mass loss is predominantly in the form of a hot, magnetically channelled wind that carries mass, but more importantly angular momentum, away from the star. This wind determines the rotational evolution of cool stars and is intimately connected to the process of field generation deep inside the star. Mass loss also occurs in a sporadic way in the form of the ejection of cool clouds of coronal gas. The coronal distribution and evolution of these clouds (or prominences) gives us vital clues about the structure and short-timescale evolution of stellar coronae. In this review I will discuss recent advances in our understanding of the coronae, winds and accretion processes in cool stars and show how these processes may be related at different stages of evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In the past 10 years, observations from space have generated a genuine revolution in our understanding of the Sun. Its interior is now “observed” down to a few % of the solar radius, its internal dynamics, its rotation and the large scale flows that are found to exist under its “surface” are studied continuously for over nearly a complete solar cycle. The mechanisms that underlie solar activity are better understood as well as their effects on the heliosphere and on the planets of the Solar System, in particular on the Earth.

However, there are still opened questions that deserve to be answered through a new generation of space instruments, requiring the best experts in the world and an extended fleet of space missions that no single country is able today to undertake alone. In this context, the International Living with a Star programme is a key element that must be pursued with full strength. At the same time, new missions that are not part of that programme should begin to be studied. They will provide the ultimate resolution and accuracy that are necessary to go a step further in the knowledge of the Sun and of its effects on our planet.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html