Understanding the formation and evolution of large-scale structure is a central problem in cosmology and enables precise tests of General Relativity on cosmological scales and constraints on dark energy. An essential ingredient is an accurate description of the pairwise velocities of biased tracers of the matter field. In this paper we compute the first and second moments of the pairwise velocity distribution by extending the Convolution Lagrangian Perturbation theory (CLPT) formalism of Carlson et al. (2012). Our predictions outperform standard perturbation theory calculations in many cases when compared to statistics measured in N-body simulations. We combine the CLPT predictions of real-space clustering and velocity statistics in the Gaussian streaming model of Reid & White (2011) to obtain predictions for the monopole and quadrupole correlation functions accurate to 2 and 4 per cent respectively down to < 25h −1 Mpc for halos hosting the massive galaxies observed by SDSS-III BOSS. We also discuss contours of the 2D correlation function and clustering "wedges". We generalize the scheme to cross-correlation functions.

Magnetized winds may be important in dispersing protoplanetary disks and influencing planet formation. We carry out global full magnetohydrodynamic simulations in axisymmetry, coupled with ray-tracing radiative transfer, consistent thermochemistry, and non-ideal MHD diffusivities. Magnetized models lacking EUV photons (hν > 13.6 eV) feature warm molecular outflows that have typical poloidal speeds 4 km s −1 . When the magnetization is sufficient to drive accretion rates ∼ 10 −8 M yr −1 , the wind mass-loss rate is comparable. Such outflows are driven not centrifugally but by the pressure of toroidal magnetic fields produced by bending the poloidal field. Both the accretion and outflow rates increase with the poloidal field energy density, the former almost linearly. The mass-loss rate is also strongly affected by ionization due to UV and X-ray radiation near the wind base. Adding EUV irradiation to the system heats, ionizes, and accelerates the part of the outflow nearest the symmetry axis, but reduces the overall mass-loss rate by exerting pressure on the wind base. Most of our models are non-turbulent, but some with reduced dust abundance and therefore higher ionization fractions exhibit magnetorotational instabilities near the base of the wind.

Photoevaporation is an important dispersal mechanism for protoplanetary disks. We conduct hydrodynamic simulations coupled with ray-tracing radiative transfer and consistent thermochemistry to study photoevaporative winds driven by ultraviolet and X-ray radiation from the host star. Most models have a three-layer structure: a cold midplane, warm intermediate layer, and hot wind, the last having typical speeds ∼ 30 km s −1 and mass-loss rates ∼ 10 −9 M yr −1 when driven primarily by ionizing UV radiation. Observable molecules including CO, OH and H 2 O re-form in the intermediate layer and survive at relatively high wind temperatures due to reactions being out of equilibrium. Mass-loss rates are sensitive to the intensity of radiation in energy bands that interact directly with hydrogen. Comparison with previous works shows that mass loss rates are also sensitive to the treatment of both the hydrodynamics and the thermochemistry. Divergent results concerning the efficiency of X-ray photoevaporation are traced in part to differing assumptions about dust and other coolants.

Super-puffs" are planets with anomalously low mean densities ( 10 −1 g cm −3 ). With a low surface gravity, the extended atmosphere is susceptible to extreme hydrodynamic mass loss ("boil off") on a timescale much shorter than the system's age. Even more puzzling, super-puffs are estimated to have a scale height of ∼ 3000 km, yet recent observations revealed completely flat transmission spectra for Kepler 51b and 51d. We investigate a new scenario that explains both observations: non-static outflowing (Ṁ 10 −10 M ⊕ yr −1 ) atmospheres that carry very small dust grains (∼ 10Å in size, ∼ 10 −2 in mass fraction) to high altitudes ( 10 −6 bar). Dust at high altitudes inflates the observed transit radius of the planet while flattens the transmission spectra.Previous static atmospheric models struggles to achieve cloud elevation and production of photochemical haze at such high altitudes.We propose to test this scenario by extending the wavelength coverage of transmission spectra. If true, dusty atmospheric outflows may affect many young ( 10 9 yr), low mass ( 10 M ⊕ ) exoplanets, thereby limit our ability to study the atmospheric composition in transmission, and inflate the observed transit radius of a planet hence obscure the underlying mass-radius relationship.