Stellar streams are a promising tool to study the Milky Way's dark matter subhalo population, as interactions with subhalos could produce substructure in streams. However, other possible causes for first need be well understood. Here we studied kinematics and unusual morphology of stellar stream Jhelum. Using combination ground-based photometry Gaia EDR3 astrometry, characterized We combined th...

We present phase-resolved spectroscopy of the bright, eclipsing polar HU Aqr obtained with high time (∼30 sec) and spectral (1.6Å) resolution when the system was in a high accretion state. The trailed spectrograms reveal clearly the presence of three different line components with different width and radial velocity variation. By means of Doppler tomography their origin could be located unequiv...

A simple analytical model is presented for the removal of stream-borne contaminants by hyporheic exchange across duned or rippled streambeds. The model assumes a steady-state balance between contaminant supply from the stream and first-order reaction in the sediment. Hyporheic exchange occurs by bed form pumping, in which water and contaminants flow into bed forms in high-pressure regions (down...

Observations show significant Hα-emissions in the Galactic halo near the edges of cold gas clouds of the Magellanic Stream. The source for the ionization of the cold gas is still a widely open question. In our paper we discuss the critical velocity effect as a possible explanation for the observed Hα-emission. The critical velocity effect can yield a fast ionization of cold gas if this neutral ...

To test a conceptual model of non-linear response of hydrologic regimes to watershed characteristics, we selected 48 secondand third-order study sites on the North and South Shores of western Lake Superior, MN (USA) using a random-stratified design based on hydrogeomorphic region, fraction mature forest, and fraction watershed storage (lakeCwetland area/watershed area). We calculated several co...

Modeling of turbulence for Large Eddy Simulations (LES) must be based on sound understanding of the relationships between large and small scales. In order to study flows with a large range of active length-scales, high Reynolds number experimental data can be used. Thermal anemometry provides the possibility of acquiring long records of turbulence data, which are necessary for evaluating statis...

We present a simple result in which the distance gradient along a stream can be used to derive the transverse velocity (i.e. proper motion) along it, if the line-of-sight velocity is also known. We show its application to a mock orbit to illustrate its validity and usage. For less extended objects, such as globular clusters and satellite galaxies exhibiting signs of tidal disruption, the same r...

A mathematical model is constructed to study the effect of heat transfer and elasticity of flexible walls in swallowing of food bolus through the oesophagus. The food bolus is supposed to be Jeffrey fluid and the geometry of wall surface of oesophagus is considered as peristaltic wave. The expressions for temperature field, axial velocity, transverse velocity and stream function are obtained un...