Astrophysics collection (March 11, 2016)

Latest astrophysics news

Rotation curves of galaxies as a test of MOND?

Galaxies are rotating with such speed that the gravity generated by their observable matter could not possibly hold them together. In a recent paper (Haghi et al. 2016) the authors test the Modified Newtonian Dynamics (MOND). Read>>

A binary origin for a central compact object (CCO)?

Doroshenko et al. 2016 investigate the possible binary origin of the CCO XMMUJ173203.3-344518. Read>>

Rapidly rotating pulsars as possible sources of fast radio bursts (FRB)

In a recent paper (Lyutikov et al. 2016) the authors discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars. Read>>

Supernovae from WD-WD direct collisions

In recent years it was suggested that WD-WD direct collisions (probably extremely rare and occurring only in dense stellar clusters) provide an additional channel for supernova explosions. Read>>

Telescopes Combine to Push Frontier on Galaxy Clusters

Hubblesite news. Read>>

No correlation between Fermi GBM signal and GW150914.

The electromagnetic signal detected by Fermi GBM is likely unrelated to the BH merger detected by LIGO. Read>>

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A Sapphire Super-Earth

Twenty-one light years away, in the constellation Cassiopeia, a planet by the name of HD219134 b orbits its star with a year that is just three days long. With a mass almost five times that of Earth, it is what is known as a super-Earth. Unlike our planet, however, these super-Earths were formed at high temperatures close to their host star and contain high quantities of calcium, aluminum and their oxides – including sapphire and ruby. HD219134 b is one of three candidates likely to belong to a new, exotic class of exoplanets. These objects are completely different from the majority of Earth-like planets. They have 10 to 20 percent lower densities than Earth. Researchers looked at different scenarios to explain the observed densities. For example, a thick atmosphere could lead to a lower overall density. But two of the exoplanets studied, 55 Cancri e and WASP-47 e, orbit their star so closely that their surface temperature is almost 3,000 degrees and they would have lost this ...

Contributions to Cosmic Reionization from Dark Matter Annihilation and Decay

Image: A Schematic Outline of the Cosmic History - Credit: NASA/WMAP Science Team The epoch of reionisation and the emergence of the universe from the cosmic dark ages is a subject of intense study in modern cosmology.

New research looks at how ‘cosmic web’ of filaments alters star formation in galaxies

Cosmic Web. Credit: NASA Astronomer Gregory Rudnick sees the universe crisscrossed by something like an interstellar superhighway system. Filaments — the strands of aggregated matter that stretch millions of light years across the universe to connect galaxy clusters — are the freeways. “Galaxies will flow along filaments from less dense parts of the universe to more dense parts of the universe, kind of like cars flowing down a highway to the big city. In this case, they are going toward big clusters, being pulled by the gravity of those large concentrations of matter,” he said. “I’m interested in how galaxies are affected by the regions in which they live,” Rudnick said. “Filaments are the first place where galaxies come into contact with higher density regions of the universe. If a galaxy in a ‘rural’ part of the universe enters a dense part, I want to know how its properties change — for example, does it change the number of stars it forms, or does its shape get altered? Us...

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