Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and optically active semiconductor nanomembrane. The cooling is a result of electron–hole generation by...

Emission by the H3(+) molecular ion may be important in determining the energy balance in astrophysical situations, such as in (exo)planetary atmospheres. Here we report the calculation of a new cooling function, based on refitted partition functions and a recalculation of the total energy emitted by the molecule. This new function gives significantly increased cooling at higher temperatures, t...

It is generally argued that most clusters of galaxies host cooling flows in which radiative cooling in the centre causes a slow inflow. However, recent observations by Chandra and XMM conflict with the predicted cooling flow rates. It has been suggested that radio jets that are situated at the centre of clusters of galaxies can assist in reducing the deposition of cold gas. Radio jets inflate c...

To define a framework for the formation and evolution of the cooling cores in X-ray galaxy clusters, we study how the physical properties change as function of the cosmic time in the inner regions of a 4 keV and 8 keV galaxy cluster under the action of radiative cooling and gravity only. The cooling radius, Rcool, defined as the radius at which the cooling time equals the Universe age at given ...

[1] Since the middle of the last century, global surface air temperature exhibits an increasing trend, with nocturnal temperatures increasing at a much higher rate. Proposed causative mechanisms include the radiative impact of atmospheric aerosols on the nocturnal boundary layer (NBL) where the temperature response is amplified due to shallow depth and its sensitivity to potential destabilizati...

The interaction of shortwave and infrared radiation in the atmosphere with clouds and greenhouse gases represents a complex process that contributes significantly to maintaining earth's climate system. For climate model simulations to become more accurate, it is essential that this process be modeled properly as verified by direct comparisons with observations and with results from a validated ...