Query : 2009A&A...508...17S

2009A&A...508...17S - Astronomy and Astrophysics, volume 508, 17-43 (2009/12-2)

Breaking the self-averaging properties of spatial galaxy fluctuations in the Sloan Digital Sky Survey - Data release six.


Abstract (from CDS):

Statistical analyses of finite sample distributions usually assume that fluctuations are self-averaging, i.e. statistically similar in different regions of the given sample volume. By using the scale-length method, we test whether this assumption is satisfied in several samples of the Sloan Digital Sky Survey Data Release Six. We find that the probability density function (PDF) of conditional fluctuations, if filtered on large enough spatial scales (i.e., r>30Mpc/h), shows relevant systematic variations in different subvolumes of the survey. Instead for scales of r<30Mpc/h, the PDF is statistically stable, and its first moment presents scaling behavior with a negative exponent around one. Thus while up to 30Mpc/h galaxy structures have well-defined power-law correlations, on larger scales it is not possible to consider whole sample average quantities as meaningful and useful statistical descriptors. This situation stems from galaxy structures corresponding to density fluctuations that are too large in amplitude and too extended in space to be self-averaging on such large scales inside the sample volumes: galaxy distribution is inhomogeneous up to the largest scales, i.e. r≃100Mpc/h probed by the SDSS samples. We show that cosmological corrections, such as K-corrections and standard evolutionary corrections, do not qualitatively change the relevant behaviors. We consider in detail the relation between several statistical measurements generally used to quantify galaxy fluctuations and the scale-length analysis by discussing how the breaking of self-averaging properties makes it impossible to have a reliable estimation of average fluctuations amplitude, variance, and correlations for r>30Mpc/h. Finally we show that the large-amplitude galaxy fluctuations observed in the SDSS samples are at odds with the predictions of the standard ΛCDM model of structure formation.

Abstract Copyright:

Journal keyword(s): cosmology: observations - large-scale structure of Universe

Simbad objects: 1

goto Full paper

goto View the references in ADS

Number of rows : 1
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME Sloan Great Wall ? ~ ~           ~ 173 0

Query : 2009A&A...508...17S

Basic data :
NAME Sloan Great Wall -- Object of Unknown Nature
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
No Coord.

Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

The count displayed here is the number of children objects.
The list obtained by clicking the button may be larger, as some children may be linked with different references or probability.

%This number is the number of distinct objets linked, by using this button, you will obtain all links (may be more than one) from that object to his children

: 1
Display criteria :

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (2) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

NAME SDSS Great Wall NAME Sloan Great Wall

References (173 between 1850 and 2023) (Total 173)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
Follow new references on this object
                Reference summaries :

                from: to:

                 or select by : (not exhaustive, explanation here)

Annotations :
Annotations allow a user to add a note or report an error concerning the astronomical object and its data. It requires registration to post a note. See description .
Please, have a look at Best practices. The list of all annotations to SIMBAD objects can be found here .

Currently no annotations available

add an annotation to this object

report an error concerning the data of this object

To bookmark this query, right click on this link: simbad:objects in 2009A&A...508...17S and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact