Black Holes——find and binary and interesting stuffs

Today, I heard an interesting topic from Avi Loeb, just about Black Holes. An fantastic topic?  I see many works leaded or participate by the lecturer and every topic is interesting for me,  and I think you will feel the same.

Start with an attractive images, what a BH should look like, black of course. But we can see it from the emissions of the disk and they will tell us about the spin of the galaxies and what is really happening around it, die or burst !

Then, really sciences come, one by one. (just some parts I try to recall.)

(1) Look the horizons of SgrA* and M87

(2) black hole binary and so on

(3) black hole recoil 

(4) tidal disruption

(5) small black holes, BH seeds ?

(6) the gas around Sgr A* in the later few months

At last, for the first time, I heard the word,  "Primordial black holes (PBHs)". Which form in the beginning of the big ban and the mass  span a wide range of masses,10−5g < M < 105M⊙. For the collisionless and nonrelativistic, they are natural dark matter (DM) candidates, which are amazing!!

But the observations have constraint such possibility and nagative results is got for the massive PBHs.

The next generation will constrain to the mass 10^-5 sun BHs. There is a latest paper about this topic:
http://arxiv.org/pdf/1307.5176v2.pdf

STScI FALL COLLOQUIUM SERIES

Wednesday, November 6, 2013

3:30 p.m. -- Bahcall Auditorium  Preceded by light refreshments at 3:15 p.m.

Avi Loeb      Harvard  University

Title

A Closer Look at Black Holes

Abstract

Several new techniques are currently being employed to probe the strong gravitational field in the vicinity of supermassive black holes. Long baseline interferometry at sub-millimeter wavelengths sets constraints on the silhouette of the black holes in the Galactic center (SgrA*) and M87. Stars which get tidally disrupted as they orbit too close to a single black hole are being discovered at cosmological distances. Electromagnetic counterparts of black hole binaries in galaxy mergers are being identified, and can be used to calibrate the rate of gravitational wave sources.  Most interestingly, the recoil induced by the anisotropic emission of gravitational waves in the final plunge of binaries leaves unusual imprints on their host galaxies.