Here we discuss the X-ray emission properties from the hot thermalized plasma that results from the collisions of individual stellar winds and supernovae ejecta within rich and compact star clusters. We propose a simple analytical way of estimating the X-ray emission generated by super star clusters and derive an expression that indicates how this X-ray emission depends on the main cluster parameters. Our model predicts that the X-ray luminosity from the star cluster region is highly dependent on the star cluster wind terminal speed, a quantity related to the temperature of the thermalized ejecta. We have also compared the X-ray luminosity from the SSC plasma with the luminosity of the interstellar bubbles generated from the mechanical interaction of the high velocity star cluster winds with the ISM. We found that the hard (2.0 keV -8.0 keV) X-ray emission is usually dominated by the hotter SSC plasma whereas the soft (0.3 keV -2.0 keV) component is dominated by the bubble plasma. This implies that compact and massive star clusters should be detected as point-like hard X-ray sources embedded into extended regions of soft diffuse X-ray emission. We also compared our results with predictions from the population synthesis models that take into consideration binary systems and found that in the case of young, massive and compact super star clusters the X-ray emission from the thermalized star cluster plasma may be comparable or even larger than that expected from the HMXB population.

In this work, we present a comprehensive X‐ray picture of the interaction between a super star cluster and the interstellar medium. In order to do that, we compare and combine the X‐ray emission from the superwind driven by the cluster with the emission from the wind‐blown bubble. Detailed analytical models for the hydrodynamics and X‐ray luminosity of fast polytropic superwinds are presented. The superwind X‐ray luminosity models are an extension of the results obtained in Paper I. Here, the superwind polytropic character allows us to parametrize a wide variety of effects, for instance, radiative cooling. Additionally, X‐ray properties that are valid for all bubble models taking thermal evaporation into account are derived. The final X‐ray picture is obtained by calculating analytically the expected surface brightness and weighted temperature of each component. All of our X‐ray models have an explicit dependence on metallicity and admit general emissivities as functions of the hydrodynamical variables. We consider a realistic X‐ray emissivity that separates the contributions from hydrogen and metals. The paper ends with a comparison of the models with observational data.

Here, we model the effect of non-uniform dynamical mass distributions and their associated gravitational fields on the stationary galactic superwind solution. We do this by considering an analogue injection of mass and energy from stellar winds and SNe. We consider both compact dark-matter and baryonic haloes that does not extend further from the galaxies optical radii R opt as well as extended gravitationally-interacting ones. We consider halo profiles that emulate the results of recent cosmological simulations and coincide also with observational estimations from galaxy surveys. This allows to compare the analytical superwind solution with outflows from different kinds of galaxies. We give analytical formulae that establish when an outflow is possible and also characterize distinct flow regimes and enrichment scenarios. We also constraint the parameter space by giving approximate limits above which gravitation, self-gravitation and radiative cooling can inhibit the stationary flow. We obtain analytical expressions for the free superwind hydrodynamical profiles. We find that the existence or inhibition of the superwind solution highly depends on the steepness and concentration of the dynamical mass and the mass and energy injection rates. We compare our results with observational data and a recent numerical work. We put our results in the context of the mass-metallicity relationship to discuss observational evidence related to the selective loss of metals from the least massive galaxies and also discuss the case of massive galaxies.

Here, we analyse the character of the turbulence of the Huygens Region in the Orion Nebula (M 42) using structure functions. We compute the second order structure function of a high resolution velocity map in Hα obtained through the M USE instrument. Ours is one of the few works that follows a mathematically sound methodology for calculating the second order structure function of astronomical velocity fields. Because of that our results will be useful for future comparisons with other studies of M 42 or other regions. We first analyse the Probability Distribution Function (PDF) and found it consistent with those resulting from numerical simulations of solenoidal turbulence. After a further analysis of the data, we found two possible separate motions or at least regimes in the region. This is confirmed later through the calculation of several filtered structure functions. We found that the turbulence in the Huygens Region is between the Kolmogorov regime (S 2 ∝ δr 2/3 ) and the Burgers regime (S 2 ∝ δr). We found that the turbulence in the region consists on two flow regimes that reproduce a generalised Larson's Law, S 2 ∼ δr 0.74−0.76 .

In this second communication we continue our analysis of the turbulence in the Huygens Region of the Orion Nebula (M 42). We calculate the associated transverse structure functions up to order 8-th and find that the higher-order transverse structure functions are almost proportional to the second-order transverse structure function: we find that after proper normalisation, the higher-order transverse structure functions only differ by very small deviations from the second-order transverse structure function in a sub-interval of the inertial range. We demonstrate that this implies that the turbulence in the Huygens Region is quasi-log-homogeneous, or to a better degree of approximation, binomially weighted log-homogeneous in the statistical sense, this implies that there is some type of invariant statistical structure in the velocity field of the Huygens Region. We also obtain and analyse the power-spectrum of the turbulent field and find that it displays a large tail that follows very approximately two power-laws, one of the form E(k)∝k−2.7 for the initial side of the tail, and one of the form E(k)∝k−1 for the end of the tail. We find that the power-law with exponent β ∼ −2.7 corresponds to spatial scales of 0.0301–0.6450 pc. We find that the exponent of the first power-law β ∼ −2.7 is related to the exponent α2 of the second-order structure function in the inertial range. We interpret the second power-law with exponent β ∼ −1 as an indicator of viscous-dissipative processes occurring at scales from δr = 1–5 pixels which correspond to spatial scales of 0.00043–0.00215 pc.