The Scale of Homogeneity in the Las Campanas Redshift Survey

Amendola, Luca; Palladino, Emilia

doi:10.1086/311936

Cited by 32 publications

(33 citation statements)

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“…In accordance with the new results in the fractal analysis of redshift surveys (Amendola & Palladino 1999;Joyce, Montuori, & Sylos Labini 1999) the galaxy clustering is described well by the fractal distribution with size D == 2 on the scale 20-30 Mpc. Our estimation of the characteristic size in the object space distribution is close to other authors data.…”

supporting

confidence: 87%

The Luminosity Periodicity of Galaxies and Quasars in the Decametric Range

Miroshnichenko¹

2002

Symp. - Int. Astron. Union

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Abstract. Estimations of the possible activity periods of galaxies and quasars were made from the UTR-2 catalogue samples by two methods.If we assume that observed periodicity of the redshift distribution is caused by the recurrent nuclear activity, then a periodicity in the object luminosity distribution must also be seen. The results of our earlier work (Miroshnichenko 1994) favoured this assumption because the characteristic luminosity function evolution time was estimated to be less than the corresponding cosmological time.To estimate the possible activity periods we used the statistically complete samples of 114 galaxies and 69 quasars, taken from from the UTR-2 catalogue at 25 MHz in the declination zone 8 = -13 0 -+20 0 for which optical data was available. The sample selection criteria for objects were: 825~20 Jy, mv~18.5 m , where 8 25 is the flux density at 25 MHz, mv the visual magnitude.The UTR-2 sensitivity for discrete sources 25 MHz measurements is 10 Jy. The sample galaxies occupy the redshift range Z = 0.002 -0.881, and the sample quasars occupy Z = 0.129 -2.975 with mean value (z)~0.1 for galaxies and (z)~1.0 for quasars.Let us the estimate of activity period as the difference D.tL of the corresponding cosmological times t for the same luminosity objects from two subsamples: (1) for redshifts z less than (z) and (2) for redshifts z more than (z). The cosmological time calculations were carried out within the framework of Friedmann model (Zeldovich & Novikov 1975) with qo=0.25 and Ho=100 km S-l Mpc-1 . So, the simple activity period estimation is:where tL(Z(1)), tL(Z(2)) -the cosmological times for objects with same luminosity L in our subsamples (1) and (2), respectively. These possible activity period values for sample galaxies and for sample quasars in the decametric and optical ranges are from 10 8 to 10 9 years. We derived power spectra (periodograms) P(v) (Deeming 1975) to find the periodicities in the sample object luminosity distribution with redshift. Our periodogram analysis revealed significant peaks (significance level is Q = 97 -99% for the quasar luminosity distribution at redshifts zp = 2.222; 1.124 in both decametric and optical ranges, and at redshift zp = 0.448 in optical. Besides, we found the periodicity peak of optical luminosity at zp = 0.224 (Q = 93.5%). The galaxy sample luminosity peaks were determined at zp = 0.200 (Q = 98%) in the decametric range and at zp = 0.0125 (Q = 90.5%) in optical. The subsample 56 of use, available at https://www.cambridge.org/core/terms. https://doi

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confidence: 87%

The Luminosity Periodicity of Galaxies and Quasars in the Decametric Range

Miroshnichenko¹

2002

Symp. - Int. Astron. Union

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“…The analysis of Kurokawa, Morikawa, & Mouri (2001) shows this to occur at a length scale of $30 h À1 Mpc, whereas Best (2000) fails to find a transition to homogeneity even on the largest scale analyzed. The analysis of Amendola & Palladino (1999) shows a fractal behavior on scales less than $30 h À1 Mpc but is inconclusive about the transition to homogeneity. The results presented in this paper set a lower limit to this length scale at around 80 h À1 Mpc, in keeping with estimates based on the multifractal analysis of LCRS by Bharadwaj, Gupta, & Seshadri (1999), who find that the LCRS exhibits homogeneity on the scales 80-200 h À1 Mpc.…”

Section: Discussionmentioning

confidence: 96%

The Size of the Longest Filaments in the Universe

Bharadwaj

Bhavsar

Sheth

2004

ApJ

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We analyze the filamentarity in the Las Campanas redshift survey (LCRS) and determine the length scale at which filaments are statistically significant. The largest length scale at which filaments are statistically significant, real objects is between 70 and 80 h À1 Mpc for the LCRS À3 slice. Filamentary features longer than 80 h À1 Mpc, although identified, are not statistically significant; they arise from chance alignments. For the five other LCRS slices, filaments of lengths 50-70 h À1 Mpc are statistically significant, but not beyond. These results indicate that while individual filaments up to 80 h À1 Mpc are statistically significant, the impression of structure on larger scales is a visual effect. On scales larger than 80 h À1 Mpc, the filaments interconnect by statistical chance to form the filament-void network. The reality of the 80 h À1 Mpc features in the À3 slice makes them the longest coherent features in the LCRS. While filaments are a natural outcome of gravitational instability, any numerical model that attempts to describe the formation of large-scale structure in the universe must produce coherent structures on scales that match these observations.

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“…The multifractal analysis (Martinez & Jones 1990;Coleman & Pietronero 1992;Borgani 1995) uses the scaling of different moments of n(< r) to characterize the scale of homogeneity. Some of the studies carried out so far with these methods on different galaxy surveys claim to have found a transition to homogeneity on sufficiently large scales 70 − 150 h −1 Mpc (Martinez & Coles 1994;Guzzo 1997;Martinez et al 1998;Bharadwaj et al 1999;Pan & Coles 2000;Kurokawa et al 2001;Hogg et al 2005;Yadav et al 2005;Sarkar et al 2009;Scrimgeour et al 2012;Pandey et al 2015) whereas some studies claim the absence of any such transition out to scale of the survey (Coleman & Pietronero 1992;Amendola & Palladino 1999;Sylos Labini et al 2007, 2009aSylos Labini 2011b). Bulk flow measurements on large scales provide another important test for the large scale homogeneity.…”

Section: Introductionmentioning

confidence: 99%

Probing large scale homogeneity and periodicity in the LRG distribution using Shannon entropy

Pandey

Sarkar

2016

Mon. Not. R. Astron. Soc.

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We quantify the degree of inhomogeneity in the Luminous Red Galaxy (LRG) distribution from the SDSS DR7 as a function of length scales by measuring the Shannon entropy in independent and regular cubic voxels of increasing grid sizes. We also analyze the data by carrying out measurements in overlapping spheres and find that it suppresses inhomogeneities by a factor of 5 to 10 on different length scales. Despite the differences observed in the degree of inhomogeneity both the methods show a decrease in inhomogeneity with increasing length scales which eventually settle down to a plateau at ∼ 150 h −1 Mpc. Considering the minuscule values of inhomogeneity at the plateaus and their expected variations we conclude that the LRG distribution becomes homogeneous at 150 h −1 Mpc and beyond. We also use the Kullback-Leibler divergence as an alternative measure of inhomogeneity which reaffirms our findings. We show that the method presented here can effectively capture the inhomogeneity in a truly inhomogeneous distribution at all length scales. We analyze a set of Monte Carlo simulations with certain periodicity in their spatial distributions and find periodic variations in their inhomogeneity which helps us to identify the underlying regularities present in such distributions and quantify the scale of their periodicity. We do not find any underlying regularities in the LRG distribution within the length scales probed.

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The Scale of Homogeneity in the Las Campanas Redshift Survey

Cited by 32 publications

References 12 publications

The Luminosity Periodicity of Galaxies and Quasars in the Decametric Range

The Luminosity Periodicity of Galaxies and Quasars in the Decametric Range

The Size of the Longest Filaments in the Universe

Probing large scale homogeneity and periodicity in the LRG distribution using Shannon entropy

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