Category Archives: Notes

These are usually notes from talks that I’ve attended.

A bash function to make movies

I use ffmpeg often to make and modify movies. But when creating movies from image sequences, ffmpeg requires the movies to be sequentially numbered. Some time ago, I wrote a bash function that create temporary symbolic links to the image files from which ffmpeg can create a movie. You can find the function below, and an example call is

that produces a movie output.mp4 at 15 frames/sec from the files included in the wildcard.

 

How I post arXiv papers everyday

For the handful of people that keep up with my astro-ph postings, I figured to share my python script that automates this process because manual posting would be extremely tedious. The script asks for an arXiv number, and then retrieves the title, authors, and PDF. It asks the user for categories for the WordPress site and a filename to save the PDF. After this, then it creates some HTML for the post and uploads it to this site.

Continue reading How I post arXiv papers everyday

KITP Notes – Massive Black Holes – Friday

Novak – “Hydrodynamic simulations of black hole fueling and feedback”

  • “Nuclear physics”: not analytic, non-local, inhomogeneous, coupled at vastly different length scales, energy generation affects fueling
  • Axi-symmetric simulations: 2.5pc to 250kpc scales, run for Gyrs.  See his papers in the last few years. Physically rich model (RT, feedback, dust models & opacity, etc.) Continue reading KITP Notes – Massive Black Holes – Friday

KITP Notes – Massive Black Holes – Thurs PM

Gültekin – “Probing the black hole-­‐galaxy scaling relations: present and past”

  • Uncorrelated BH seeding -> M-sigma.  I first saw this in a conference in Potsdam (2010). Interesting, but they considered a 100% occupation fraction. Peng (2007), Jahnke & Maccio (2010).
  • Low scatter in M-sigma, but there are some outliers (e.g. NGC 1277)! Forming too many / little stars.  Are there selection effects?
  • Low-mass end is important to understand the BH seeds
  • High-mass end is also important! 1010 Msun implied in some hosts.

Continue reading KITP Notes – Massive Black Holes – Thurs PM