May 11th, 2008| 10:42 pm | Posted by hlee
I think I have to review spatial statistics in astronomy, focusing on tessellation (void structure), point process (expanding 2 (3) point correlation function), and marked point process (spatial distribution of hardness ratios of X-ray distant sources, different types of galaxies -not only morphological differences but other marks such as absolute magnitudes and existence of particular features). When? Someday…
In addition to Bayesian methodologies, like this week’s astro-ph, studies on characterizing empirical spatial distributions of voids and galaxies frequently appear, which I believe can be enriched further with the ideas from stochastic geometry and spatial statistics. Click for what was appeared in arXiv this week. Continue reading ‘[ArXiv] 1st week, May 2008’ »
Tags:
Classification,
covariance,
FARIMA,
Fisher information,
GL,
GRB,
Levy,
light curve,
limb darkening,
ML,
Pareto distribution,
quasars,
solar flare,
standard candle,
tessellation,
time series,
VO,
void Category:
arXiv,
MCMC,
Uncertainty |
1 Comment
Apr 18th, 2008| 01:51 pm | Posted by hlee
Sep 8th, 2007| 02:31 pm | Posted by vlk
Google Sky is good for a quick look “what’s that you just saw over there?”, but not for anything more than that. Not yet anyway. Mind you, I think it is a good thing. It is easy to use, and definitely worth a look as an astronomy popularization tool. But there are a number of astro visualization programs that can (so to speak) beat the pants off Google Sky with one hand tied behind the back. Check these out (all open source): Continue reading ‘Beyond Google Sky’ »
Jul 25th, 2007| 02:28 am | Posted by hlee
Since I began to subscribe arxiv/astro-ph abstracts, from an astrostatistical point of view, one of the most frequent topics has been photometric redshifts. This photometric redshift has been a popular topic as the catalog of remote photometric object observation multiplies its volume and sky survey projects in multiple bands lead to virtual observatories (VO – will discuss in the later posting). Just searching by photometric redshifts in google scholar and arxiv.org provides more than 2000 articles since 2000.
Continue reading ‘Photometric Redshifts’ »
Tags:
cosmology,
distance estimation,
Lutz-Kelker bias,
machine learning,
Malmquist bias,
Photometric Redshift,
spectrum,
survey,
VO Category:
Algorithms,
arXiv,
Data Processing,
Galaxies,
Stat |
Comment
Jul 18th, 2007| 01:04 am | Posted by hlee
From arxiv/astro-ph:0707.2474,
Visualization, Exploration and Data Analysis of Complex Astrophysical Data by Comparato, Becciani, Costa, Larsson, Garilli, Gheller, and Taylor
This paper introduces a novel advanced visualization tool VisIVO,[] its advantages from combining a protocol called PLASTIC (Platform for Astronomy Tool Interconnection) for displaying and extracting information from astrophysical data, its enhanced connection to VO (Virtual Observatory), and its usage in several scientific cases. Continue reading ‘[ArXiv] Data Visualization, July 17, 2007’ »
Jul 2nd, 2007| 06:07 pm | Posted by hlee
From arXiv/astro-ph:0706.4484
Spectroscopic Surveys: Present by Yip. C. overviews recent spectroscopic sky surveys and spectral analysis techniques toward Virtual Observatories (VO). In addition that spectroscopic redshift measures increase like Moore’s law, the surveys tend to go deeper and aim completeness. Mainly elliptical galaxy formation has been studied due to more abundance compared to spirals and the galactic bimodality in color-color or color-magnitude diagrams is the result of the gas-rich mergers by blue mergers forming the red sequence. Principal component analysis has incorporated ratios of emission line-strengths for classifying Type-II AGN and star forming galaxies. LyЮБ identifies high z quasars and other spectral patterns over z reveal the history of the early universe and the characteristics of quasars. Also, the recent discovery of 10 satellites to the Milky Way is mentioned.
Continue reading ‘[ArXiv] Spectroscopic Survey, June 29, 2007’ »
Tags:
bimodality,
chi-square minimization,
Classification,
CMD,
Estimation,
machine learning,
massive data,
model based,
PCA,
spectral analysis,
spectroscopic,
survey,
VO Category:
arXiv,
Astro,
Bayesian,
Data Processing,
Fitting,
Frequentist,
Methods,
Spectral |
Comment