Posts tagged ‘lensing’

[ArXiv] 3rd week, June 2008

[ArXiv] 5th week, Apr. 2008

Since I learned Hubble’s tuning fork[1] for the first time, I wanted to do classification (semi-supervised learning seems more suitable) galaxies based on their features (colors and spectra), instead of labor intensive human eye classification. Ironically, at that time I didn’t know there is a field of computer science called machine learning nor statistics which do such studies. Upon switching to statistics with a hope of understanding statistical packages implemented in IRAF and IDL, and learning better the contents of Numerical Recipes and Bevington’s book, the ignorance was not the enemy, but the accessibility of data was. Continue reading ‘[ArXiv] 5th week, Apr. 2008’ »

  1. Wikipedia link: Hubble sequence[]

[ArXiv] 4th week, Apr. 2008

The last paper in the list discusses MCMC for time series analysis, applied to sunspot data. There are six additional papers about statistics and data analysis from the week. Continue reading ‘[ArXiv] 4th week, Apr. 2008’ »

[ArXiv] 3rd week, Mar. 2007

Markov chain Monte Carlo (MCMC) never misses a week from recently astro-ph. A book titled MCMC in astronomy will be a best seller. There are, in addition, very interesting non MCMC preprints. Continue reading ‘[ArXiv] 3rd week, Mar. 2007’ »

[ArXiv] 2nd week, Mar. 2008

Warning! The list is long this week but diverse. Some are of CHASC’s obvious interest. Continue reading ‘[ArXiv] 2nd week, Mar. 2008’ »

The GREAT08 Challenge

Grand statistical challenges seem to be all the rage nowadays. Following on the heels of the Banff Challenge (which dealt with figuring out how to set the bounds for the signal intensity that would result from the Higgs boson) comes the GREAT08 Challenge (arxiv/0802.1214) to deal with one of the major issues in observational Cosmology, the effect of dark matter. As Douglas Applegate puts it: Continue reading ‘The GREAT08 Challenge’ »

[ArXiv] 2nd week, Feb. 2008

Another week went by with astro-ph papers of statistical flavors. Continue reading ‘[ArXiv] 2nd week, Feb. 2008’ »

[ArXiv] GRB host galaxies, Aug. 10, 2007

From arxiv/astro-ph:0708.1510v1
Connecting GRBs and galaxies: the probability of chance coincidence by Cobb and Bailyn

Without an optical afterglow, a galaxy within the 2 arc second error region of a GRB x-ray afterglow is identified as a host galaxy; however confusion can rise due to the facts that 1. the edge of a galaxy is diffused, 2. multiple sources could exist within 2 arc second error region, 3.the distance between the galaxy and the x-ray afterglow is measured by projection, and 4. lensing causes increase of brightness and position shifts. In this paper, the authors “investigated the fields of 72 GRBs in order to examine the general issue of associations between GRBs and host galaxies.”
Continue reading ‘[ArXiv] GRB host galaxies, Aug. 10, 2007’ »