2013年11月11日星期一

Installing SExtractor on Mac

Really thanks to the author from here. You should read the article here: http://okomestudio.net/biboroku/?p=824

The easiest way to do that is using Macport! It is easy and safe.
Another way is to install from the source which I fail. The problem is exactly the same as in the blog, "IMPORTANT: I need FFTW and ATLAS installed already, and assume that FFTW was installed at /usr/local/fftw, and ATLAS at /usr/local/atlas following the source install procedures described in those notes."


2013年11月7日星期四

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.

2013年11月4日星期一

an advise for future astronomers

What advice do you think advisors should be giving students regarding their career path?


If students want to stay in astronomy, it’s important to do great research and to make sure others know about that research through publications, but also through attending professional meetings, particularly those topical meetings in the most relevant research areas where they can meet the individuals who may have funds for fellowships in the future.

For faculty positions, becoming an

engaging teacher is important and this takes practice giving talks. Advisors should give students many opportunities to present their research and advise them on how to present it more clearly and for different audiences.

Since about one-third of astronomers work in academic positions, one-third at observatories and national labs and one-third in industry, it is also very important that students broadly consider their future options. While there are currently many post-doctural positions each year, there are generally fewer job openings for more senior positions.

check the entire topic here:
http://www.astrobetter.com/career-profiles-astronomer-to-research-scientist-at-the-smithsonian-astrophysical-observatory/