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  2. Luminosity function (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Luminosity_function...

    Historically, the Schechter luminosity function was inspired by the Press–Schechter model. [ 8 ] However, the connection between the two is not straight forward. If one assumes that every dark matter halo hosts one galaxy, then the Press-Schechter model yields a slope α ∼ − 3.5 {\displaystyle \alpha \sim -3.5} for galaxies instead of the ...

  3. Press–Schechter formalism - Wikipedia

    en.wikipedia.org/wiki/Press–Schechter_formalism

    The Press–Schechter formalism predicts that the number of objects with mass between and + is: = (+) ¯ (+) / ⁡ (() (+) /). where is the index of the power spectrum of the fluctuations in the early universe (), ¯ is the mean (baryonic and dark) matter density of the universe at the time the fluctuation from which the object was formed had gravitationally collapsed, and is a cut-off mass ...

  4. Malmquist bias - Wikipedia

    en.wikipedia.org/wiki/Malmquist_bias

    The dashed red line is an example luminosity function when the Malmquist bias is not corrected for. The more numerous low luminosity objects are underrepresented because of the apparent magnitude limit of the survey. The solid blue line is the properly corrected luminosity function using the volume-weighted correction method.

  5. Paul L. Schechter - Wikipedia

    en.wikipedia.org/wiki/Paul_L._Schechter

    Paul L. Schechter (born May 30, 1948) is an American astronomer and observational cosmologist. He is the William A. M. Burden Professor of Astrophysics, Emeritus, at MIT . Schechter received his bachelor's degree from Cornell in 1968, and his Ph.D. degree from Caltech in 1975.

  6. Sheth–Tormen approximation - Wikipedia

    en.wikipedia.org/wiki/Sheth–Tormen_approximation

    In 2010, the Bolshoi cosmological simulation predicted that the Sheth–Tormen approximation is inaccurate for the most distant objects. Specifically, the Sheth–Tormen approximation overpredicts the abundance of haloes by a factor of for objects with a redshift >, but is accurate at low redshifts.

  7. Satellite galaxy - Wikipedia

    en.wikipedia.org/wiki/Satellite_galaxy

    Mathematically, the progenitor mass function is expressed as: (, |,) = | ⁡ ⁡ ⁡ ⁡ | where = and () = ⁡ is the Press-Schechter multiplicity function that describes the fraction of mass associated with halos in a range ⁡ ().

  8. Homogeneous function - Wikipedia

    en.wikipedia.org/wiki/Homogeneous_function

    A homogeneous function f from V to W is a partial function from V to W that has a linear cone C as its domain, and satisfies ... Schechter, Eric (1996).

  9. Cauchy space - Wikipedia

    en.wikipedia.org/wiki/Cauchy_space

    In general topology and analysis, a Cauchy space is a generalization of metric spaces and uniform spaces for which the notion of Cauchy convergence still makes sense. Cauchy spaces were introduced by H. H. Keller in 1968, as an axiomatic tool derived from the idea of a Cauchy filter, in order to study completeness in topological spaces.