The radial Tully–Fisher relation for spiral galaxies – I

We find a new Tully–Fisher-like relation for spiral galaxies holding at different galactocentric radii. This radial Tully–Fisher relation allows us to investigate the distribution of matter in the optical regions of spiral galaxies. This relation, applied to three different samples of rotation curves of spiral galaxies, directly proves that: (i) the rotation velocity of spirals is a good measure of their gravitational potential and both the rotation curve's amplitudes and profiles are well predicted by galaxy luminosity, (ii) the existence of a dark component, less concentrated than the luminous one, and (iii) a scaling law, according to which, inside the disc optical size:   M _dark/ M _lum= 0.5( L _B /10¹¹ L _{B ⊙})^−0.7  .     

TOPO-EUROPE: The geoscience of coupled deep Earth-surface processes

TOPO-EUROPE addresses the 4-D topographic evolution of the orogens and intra-plate regions of Europe through a multidisciplinary approach linking geology, geophysics, geodesy and geotechnology. TOPO-EUROPE integrates monitoring, imaging, reconstruction and modelling of the interplay between processes controlling continental topography and related natural hazards. Until now, research on neotectonics and related topography development of orogens and intra-plate regions has received little attention. TOPO-EUROPE initiates a number of novel studies on the quantification of rates of vertical motions, related tectonically controlled river evolution and land subsidence in carefully selected natural laboratories in Europe. From orogen through platform to continental margin, these natural laboratories include the Alps/Carpathians–Pannonian Basin System, the West and Central European Platform, the Apennines–Aegean–Anatolian region, the Iberian Peninsula, the Scandinavian Continental Margin, the East-European Platform, and the Caucasus–Levant area. TOPO-EUROPE integrates European research facilities and know-how essential to advance the understanding of the role of topography in Environmental Earth System Dynamics. The principal objective of the network is twofold. Namely, to integrate national research programs into a common European network and, furthermore, to integrate activities among TOPO-EUROPE institutes and participants. Key objectives are to provide an interdisciplinary forum to share knowledge and information in the field of the neotectonic and topographic evolution of Europe, to promote and encourage multidisciplinary research on a truly European scale, to increase mobility of scientists and to train young scientists. This paper provides an overview of the state-of-the-art of continental topography research, and of the challenges to TOPO-EUROPE researchers in the targeted natural laboratories.     

Experimental evidence for the potential impact ejection of viable microorganisms from Mars and Mars-like planets

Bacterial spores (Bacillus subtilis), cyanobacteria (Chroococcidiopsis sp.), and lichen (Xanthoria elegans) embedded in martian analogue rock (gabbro) were exposed to shock pressures between 5 and 50 GPa which is the range of pressures observed in martian meteorites. The survival of Bacillus subtilis and Xanthoria elegans up to 45 GPa and of Chroococcidiopsis sp. up to 10 GPa supports the possibility of transfer of life inside meteoroids between Mars and Earth and it implies the potential for the transfer of life from any Mars-like planet to other habitable planets in the same stellar system.     

Results of Light Curve Analysis of the Massive Binary Cyg X-1/V1357 Cyg in Primary Minimum

The results of new UBV photometric observations of V1357 Cyg in primary minimum are presented. Observations were carried out from 1996 up to now with 60 cm telescope in Crimea with the goal to study additional radiation that was detected in the mean light curve of this system near orbital phase 0.0. The properties of this additional radiation are also considered.     

The deglaciation of Clyde Inlet,northeastern Baffin Island,Arctic Canada

The behaviour of ice sheets as they retreated from their Last Glacial Maximum (LGM) positions provides insights into Lateglacial and early Holocene ice‐sheet dynamics and climate change. The pattern of deglaciation of the Laurentide Ice Sheet (LIS) in arctic fiord landscapes can now be well dated using cosmogenic exposure dating. We use cosmogenic exposure and radiocarbon ages to constrain the deglaciation history of Clyde Inlet, a 120 km long fiord on northeastern Baffin Island. The LIS reached the continental shelf during the LGM, retreated from the coastal lowlands by 12.5 ± 0.7 ka (n = 3), and from the fiord mouth by 11.7 ± 2.2 ka (n = 4). Rapid retreat from the outer fiord occurred 10.3 ± 1.3 ka (n = 6), with the terminus reaching the inner fiord shortly after 9.4 ka (n = 2), where several moraine systems were deposited between ca. 9.4 and ca. 8.4 ka. These moraines represent fluctuations of the LIS during the warmest summers since the last interglaciation, and this suggests that the ice sheet was responding to increased snowfall. Before retreating from the head of Clyde Inlet, the LIS margin fluctuated at least twice between ca. 7.9 and ca. 8.5 ka, possibly in response to the 8.2 ka cold event. Copyright © 2006 John Wiley & Sons, Ltd.     

Measurements of meteor smoke particles during the ECOMA-2006 campaign: 2. Results

The first sounding rocket of the European ECOMA-project (ECOMA, Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was launched on 8 September 2006. Measurements with a new particle detector described in the companion paper by Rapp and Strelnikova [2008. Measurements of meteor smoke particles during the ECOMA-2006 campaign: 1. Particle detection by active photoionization. Journal of Atmospheric and Solar-Terrestrial Physics, this issue, doi:10.1016/j.jastp.2008.06.002] clearly showed meteor smoke particle (MSP) signatures in both data channels. The data channels measure particles directly impacting on the detector electrode and photoelectrons from the particles actively created using ionization by the UV-photons of a xenon-flashlamp. Measured photoelectron currents resemble model expectations of the shape of the MSP layer almost perfectly, whereas derived number densities in the altitude range 60–90 km are larger than model results by about a factor of 5. Given the large uncertainties inherent to both model and the analysis of our measurements (e.g., the composition of the particles is not known and must be assumed) we consider this a satisfactory agreement and proof that MSPs do extend throughout the entire mesosphere as predicted by models. The measurements of direct particle impacts revealed a confined layer of negative charge between 80 and 90 km. This limited altitude range, however, is quantitatively shown to be the consequence of the aerodynamics of the rocket flight and does not have any geophysical origin. Measured charge signatures are consistent with expectations of particle charging given our own measurements of the background ionization. Unfortunately, however, a contamination of these measurements from triboelectric charging cannot be excluded at this stage.     

Ongoing Changes of Ionic Composition and Dissolved Gases in the Aral Sea

Starting from 1961, the Aral Sea, a major saline lake in Central Asia, has been continuously shrinking because of deficiency in its water budget. Accordingly, the salinity of the once brackish lake increased by a factor of magnitude. During the desiccation, the salt composition of the Aral Sea has been subject to continuous changes because of chemical precipitation accompanying the salinity buildup. This paper provides a summary of these changes based on water samples collected from the so-called Large Aral Sea during the field surveys of 2002–2007. Once fully ventilated, the lake developed anoxic conditions and H₂S contamination is frequently observed in the bottom layers. However, hydrogen sulfide is a variable rather than a permanent feature of the present Aral Sea. Because of the precipitation of calcium carbonate, gypsum, and, possibly, mirabilite, which successively occurred as the salinity increased, the relative content of SO₄ ^? and Ca²⁺ ions decreased. Accordingly, compared with the pre-desiccation period before 1960, the sulfate-to-chloride mass ratio decreased by 10–30%, while the relative content of calcium decreased almost 7-fold. The depletion in calcium is more pronounced in the shallow eastern part of the lake, where salinity is much higher. However, the reduction of the sulfate-to-chloride ratio in the eastern basin is smaller than that for the western basin of the Aral Sea. Hypothetically, this could be explained through precipitation of halite already taking place in the eastern basin, but not yet in the western basin. Vertical profiles of the ionic content in the relatively deep western part of the lake reveal a decrease of calcium content and relative increase of sulfate ion content toward the bottom, which is consistent with the previously published concept that the bottom layers of the western trench contain a significant admixture of the water advected from the eastern basin.     

The variations of the scaling parameters of the structure functions in solar active regions at the pre-flare stage

A series of subflares in active region NOAA 9077 (July 2000) and in the activity complex NOAA 0039 + NOAA 0050 were investigated. The structure functions and their characteristics for sets of images of active regions in the hydrogen-alpha line (H-line) were calculated. The ranges of the spatial scales of different scaling behavior of the structure functions were revealed. The existence of intermittent turbulence (multi-fractal structure) in active regions of the chromosphere is shown. Peculiarities of the scaling parameters variations of the structure functions at pre-flare stage are investigated. It was found that on average 20 min before a subflare onset considerable deviation of these variations from the mean occurs, which may be of importance for predictions. It was discovered that maximum variations of scaling parameters with an accuracy to 15 min (on average), in a number of cases coincide with variations of the elongated chromospheric structures in an active-region area. We used H_ filtergrams obtained with the chromospheric telescope of the Baikal observatory operated by ISTP SD RAS. The telescope is coupled with a Halle birefringent filter with a 0.05 nm bandpass, and a Princeton Instruments 2048 × 2048 pixel CCD camera with 16-bit amplitude resolution.