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>>

Comments

ORBITAL PERIODS OF THE PLANETS

For orbital period generally we refer to the sidereal period, that is the temporal cycle that it takes an object to make a full orbit, relative to the stars. This is the orbital period in an inertial (non-rotating) frame of reference (365,25 days for the earth).

THE HITCHCHIKER'S GUIDE TO THE LOCAL SUPERCLUSTER

Image: Virgo Supercluster. Credit: Andrew Z. Colvin The Virgo Supercluster is a region with a diameter of 33 megaparsecs (~1000 times larger the Milky Way's diameter) containing at least 100 galaxy groups and clusters.

ALMA Discovers Cold Dust Around Nearest Star

This artist’s impression shows how the newly discovered belts of dust around the closest star to the Solar System, Proxima Centauri, may look. ALMA observations revealed the glow coming from cold dust in a region between one to four times as far from Proxima Centauri as the Earth is from the Sun. The data also hint at the presence of an even cooler outer dust belt and indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets. Note that this sketch is not to scale — to make Proxima b clearly visible it has been shown further from the star and larger than it is in reality. Credit: ESO/M. Kornmesser Proxima Centauri is the closest star to the Sun. It is a faint red dwarf lying just four light-years away in the southern constellation of Centaurus (The Centaur). It is orbited by the Earth-sized temperate world Proxima b ...

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