What do the sizes of galaxies have to tell us about cosmology? Today, we discuss how the velocity of a galaxy can change its observed size and tell us about the properties of the Universe.
There might be more information in the Hubble diagram of supernovae than we first thought. Far away supernovae are subject to gravitational lensing and in the upcoming decades, they could be used to determine how much matter there is in the Universe and how it clusters.
Gravitational lensing is the deflection of the trajectory of a photon by gravity, and it is a natural consequence of the theory of General Relativity. Lensing distorts the shapes and orientations of galaxies and in today’s post, we discuss a new method to reconstruct dark matter maps of our Universe using the position angles of galaxies.
Observing dark worlds is a public competition for improving algorithms to find dark matter halos in weak gravitational lensing maps. Today, we discuss citizen science projects and describe the results of the challenge.
We are used to thinking about planet transits in visible wavelengths. What can we learn from planet transits in the radio band? Today, we discuss what these transits might tell us about the magnetic activity and the atmosphere of a star.
Gravitational lensing causes distortions in the polarization of the Cosmic Microwave Background. In this astrobite, we discuss recent results from the South Pole Telescope collaboration measuring patterns caused by lensing in the CMB polarization. What do these patterns tell us about the Universe?
Short gamma-ray bursts, extremely energetic explosions in the Universe, might be caused by the merger of two compact objects. In the two papers we discuss today, the authors test this scenario by looking for light emitted still a few days after the explosion.
In today’s astrobite, we discuss the opacity of the Universe to high energy photons. The cosmic gamma-ray horizon, constrained by the authors of this paper, is a measure of this opacity, a cosmological probe and means of estimating blazar redshifts.
In today’s astrobite, we discuss the puzzling results from the AMS-02 experiment, which has detected an excess of positrons in cosmic rays with respect to what we expect from known physical sources. Where are those positrons coming from?