astrobites
cosmology
The Cosmic γ-Ray Horizon
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.
Closing In on the Epoch of Reionization
An array of dipole antennas in South Africa’s Karoo desert offers the best limit on the power spectrum of the Epoch of Reionization.
Closing in on Dark Matter?
The Cryogenic Dark Matter Search experiment has found signatures in its data consistent with a dark matter Weakly Interacting Massive Particle. While not confident enough to declare a dark matter discovery, they estimate that there is only a 0.2% chance that these signatures are caused by random chance.
Moving mesh code AREPO may help us understand galaxy evolution better than before
Moving mesh code AREPO looks like it will help astronomers understand the physics of galaxy formation and evolution better than its predecessors, due to an innovative new method of solving the fluid dynamics equations in astrophysical settings. This paper discusses the differences between AREPO and another code called GADGET in the case of gas accretion onto galaxies.
Seeing Galaxy formation before reionization: baryon-dark matter relative velocity helps!
Relative velocity in the early Universe between regular matter (baryons) and dark matter enhances an otherwise hard-to-detect signal and makes it likely we can look back even farther into the past.
Planck and the Hubble constant: how fast are things flying apart, and what does it mean?
A quick discussion of Planck’s new value of the Hubble constant, as part of our series on the Planck results.
Finding Galaxies at the Edge of the Universe
How can we find the distant galaxies that were responsible for bringing us out of the cosmic dark ages?
An almost perfect Universe: the Planck 2013 release (II)
In today’s astrobite, we continue our overview of the papers from the Planck 2013 release. This time, we review papers XVII and XXIII, which discuss weak gravitational lensing of the Cosmic Microwave Background, and the isotropy of the Universe at the time this background radiation was emitted.
An almost perfect Universe: the Planck 2013 release
The primordial seeds of the Universe, the Cosmic Microwave Background, have been measured by the Planck satellite with unprecedented precision. In this post, we summarize some of their results on cosmological parameters and primordial non-gaussianity.
Ram pressure stripping: a classic paper
A classic 1972 paper by Jim Gunn and J. Richard Gott, III describing the growth of clusters from primordial density perturbations and, most famously, the importance of ram pressure stripping in explaining the observed lack of spiral galaxies towards the center of clusters.
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