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 ...

‘Monster’ Planet Discovery Challenges Formation Theory

Artist’s illustration of a "hot Jupiter". Image Credit: NASA/CXC/M. Weiss A new research presents the discovery of NGTS-1b, a hot-Jupiter transiting an early M-dwarf host in a P~2.6 days orbit discovered as part of the Next Generation Transit Survey (NGTS). The planet has a mass of M~0.8 M(jupiter) making it the most massive planet ever discovered transiting an M-dwarf. NGTS-1b is the third transiting giant planet found around an M-dwarf, reinforcing the notion that close-in gas giants can form and migrate similar to the known population of hot Jupiters around solar type stars. The existence of the 'monster' planet, 'NGTS-1b', challenges theories of planet formation which state that a planet of this size could not be formed around such a small star. According to these theories, small stars can readily form rocky planets but do not gather enough material together to form Jupiter-sized planets. Such massive planets were not thought to exist ar...

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.

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