The AstroStat Slog » LMC http://hea-www.harvard.edu/AstroStat/slog Weaving together Astronomy+Statistics+Computer Science+Engineering+Intrumentation, far beyond the growing borders Fri, 09 Sep 2011 17:05:33 +0000 en-US hourly 1 http://wordpress.org/?v=3.4 [ArXiv] 4th week, Apr. 2008 http://hea-www.harvard.edu/AstroStat/slog/2008/arxiv-4th-week-apr-2008/ http://hea-www.harvard.edu/AstroStat/slog/2008/arxiv-4th-week-apr-2008/#comments Sun, 27 Apr 2008 15:29:48 +0000 hlee http://hea-www.harvard.edu/AstroStat/slog/?p=276 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.

  • [astro-ph:0804.2904]M. Cruz et al.
    The CMB cold spot: texture, cluster or void?

  • [astro-ph:0804.2917] Z. Zhu, M. Sereno
    Testing the DGP model with gravitational lensing statistics

  • [astro-ph:0804.3390] Valkenburg, Krauss, & Hamann
    Effects of Prior Assumptions on Bayesian Estimates of Inflation Parameters, and the expected Gravitational Waves Signal from Inflation

  • [astro-ph:0804.3413] N.Ball et al.
    Robust Machine Learning Applied to Astronomical Datasets III: Probabilistic Photometric Redshifts for Galaxies and Quasars in the SDSS and GALEX (Another related publication [astro-ph:0804.3417])

  • [astro-ph:0804.3471] M. Cirasuolo et al.
    A new measurement of the evolving near-infrared galaxy luminosity function out to z~4: a continuing challenge to theoretical models of galaxy formation

  • [astro-ph:0804.3475] A.D. Mackey et al.
    Multiple stellar populations in three rich Large Magellanic Cloud star clusters

  • [stat.ME:0804.3853] C. R\”over , R. Meyer, N. Christensen
    Modelling coloured noise (MCMC & sunspot data)
]]> http://hea-www.harvard.edu/AstroStat/slog/2008/arxiv-4th-week-apr-2008/feed/ 0 “you are biased, I have an informative prior” http://hea-www.harvard.edu/AstroStat/slog/2007/lmc-distance-scale/ http://hea-www.harvard.edu/AstroStat/slog/2007/lmc-distance-scale/#comments Wed, 10 Oct 2007 16:26:27 +0000 vlk http://hea-www.harvard.edu/AstroStat/slog/2007/lmc-distance-scale/ Hyunsook drew attention to this paper (arXiv:0709.4531v1) by Brad Schaefer on the underdispersed measurements of the distances to LMC. He makes a compelling case that since 2002 published numbers in the literature have been hewing to an “acceptable number”, possibly in an unconscious effort to pass muster with their referees. Essentially, the distribution of the best-fit distances are much more closely clustered than you would expect from the quoted sizes of the error bars.

To be sure, there are other possible reasons for this underdispersion, such as correlations in how the data are gathered and analyzed, and an overly conservative estimation of error bars, etc. In fact, the most benign explanation is probably in how people carry out “sanity checks” and tend to discard or explain away or correct the data that give odd results.

While this is indeed worrisome, I am inclined to think that this is not wrong per se, but rather a case where a fully Bayesian analysis would give the “right” coverage. After all, there does exist a strong prior that people are bringing into the analysis, but are not including in the calculations of the widths of the posterior probability distributions. Including such a highly informative prior will of course shrink the sizes of the error bars and make everything consistent. i.e., I think that the assumption needs to be explicit, that is all. Is that bias? bandwagon? or prior belief?

]]> http://hea-www.harvard.edu/AstroStat/slog/2007/lmc-distance-scale/feed/ 0 [ArXiv] 1st week, Oct. 2007 http://hea-www.harvard.edu/AstroStat/slog/2007/arxiv-1st-week-oct-2007/ http://hea-www.harvard.edu/AstroStat/slog/2007/arxiv-1st-week-oct-2007/#comments Sat, 06 Oct 2007 16:45:19 +0000 hlee http://hea-www.harvard.edu/AstroStat/slog/2007/arxiv-1st-week-oct-2007/ This week, instead of only filtering AstroStatistics related papers from arxiv, I chose additional arxiv/astro-ph papers related to CHASC folks’ astrophysical projects. Some of papers you see from this week do not have sophisticated statistical analysis but contain data from specific satellites and possibly relevant information related to CHASC projects. Due to the CHACS’ long history (we are celebrating the 10th birthday this year) and my being a newbie to CHASC, I may not pick up all papers related to the projects of current, former, and future CHASC members and dedicated slog readers. For creating a satisfying posting every week, your inputs are welcome to improve my adaptive filter. For the list of this week, click the following.

  • [astro-ph:0709.4598]
    Upper Limits from Hess Observations of AGN in 2005-2007 by Benbow and Buehler
  • [physics.data-an:0709.3662] provides physical insights toward some families of probability distributions
    Econophysics, Statistical Mechanics Approach to by V.M.Yakovenko
  • [astro-ph:0709.4488] could motivate developing machine learning algorithms.
    Determining the Type, Redshift, and Age of a Supernova Spectrum by S. Blondin and J.L. Tonry
  • [astro-ph:0709.4531]
    A Problem with the Clustering of Recent Measures of the Distance to the Large Magellanic Cloud by B. E. Schaefer
  • [astro-ph:0709.4601]
    Multiple stellar populations in Globular Clusters: collection of information from the Horizontal Branch by F. D’Antona and V. Caloi
  • [astro-ph:0710.0370]
    MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre by S. D. J. Gwyn
  • [astro-ph:0710.0373]
    To Bin or Not To Bin: Decorrelating the Cosmic Equation of State by R. de Putter and E. V. Linder
  • [astro-ph:0710.0619] About EGRET and GLAST
    Unresolved Unidentified Source Contribution to the Gamma-ray Background by V. Pavlidou et. al.
  • [astro-ph:0710.0757] About SOHO(MDI) and RHESSI
    The Cause of Photospheric and Helioseismic Responses to Solar Flares: High-Energy Electrons or Protons? by A. G. Kosovichev
  • [astro-ph:0710.0774]
    NGC 346 in the Small Magellanic Cloud. III. Recent Star Formation and Stellar Clustering Properties in the Bright HII Region N 66 by E. Hennekemper et.al
  • [astro-ph:0710.0874] discusses GLAST as well.
    Constraints on Galactic populations of gamma-ray emitters from the unidentified EGRET sources by J. M. Siegal-Gaskins et.al.
  • [astro-ph:0710.0875]
    Evidence of Cosmic Evolution of the Stellar Initial Mass Function by P. van Dokkum
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