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  • 1
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    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies (2016)
    Oxford University Press
    Details
    Publication Date: 2016-06-26
    Description: We present an anisotropic analysis of the baryon acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361 762 galaxies with an effective redshift of z LOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of z CMASS = 0.57. We extract the BAO peak position from the monopole power-spectrum moment, α 0 , and from the μ 2 moment, α 2 , where μ is the cosine of the angle to the line of sight. The μ 2 -moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ 2 -moment, which are related to radial and angular shifts in scale. We report H ( z LOWZ ) r s ( z d ) = (11.60 ± 0.60) x 10 3 km s –1 and D A ( z LOWZ )/ r s ( z d ) = 6.66 ± 0.16 with a cross-correlation coefficient of $r_{HD_{\rm A}}=0.41$ , for the LOWZ sample; and H ( z CMASS ) r s ( z d ) = (14.56 ± 0.37) x 10 3 km s –1 and D A ( z CMASS )/ r s ( z d ) = 9.42 ± 0.13 with a cross-correlation coefficient of $r_{HD_{\rm A}}=0.47$ , for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same data set (Cuesta et al. 2016 , companion paper) and report the consensus values: H ( z LOWZ ) r s ( z d ) = (11.63 ± 0.69) x 10 3 km s –1 and D A ( z LOWZ )/ r s ( z d ) = 6.67 ± 0.15 with $r_{HD_{\rm A}}=0.35$ for the LOWZ sample; H ( z CMASS ) r s ( z d ) = (14.67 ± 0.42) x 10 3 km s –1 and D A ( z CMASS )/ r s ( z d ) = 9.47 ± 0.12 with $r_{HD_{\rm A}}=0.52$ for the CMASS sample.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 2
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    nIFTy cosmology: Galaxy/halo mock catalogue comparison project on clustering statistics (2015)
    Oxford University Press
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    Publication Date: 2015-07-10
    Description: We present a comparison of major methodologies of fast generating mock halo or galaxy catalogues. The comparison is done for two-point (power spectrum and two-point correlation function in real and redshift space), and the three-point clustering statistics (bispectrum and three-point correlation function). The reference catalogues are drawn from the BigMultiDark N -body simulation. Both friend-of-friends (including distinct haloes only) and spherical overdensity (including distinct haloes and subhalos) catalogues have been used with the typical number density of a large volume galaxy surveys. We demonstrate that a proper biasing model is essential for reproducing the power spectrum at quasi-linear and even smaller scales. With respect to various clustering statistics, a methodology based on perturbation theory and a realistic biasing model leads to very good agreement with N -body simulations. However, for the quadrupole of the correlation function or the power spectrum, only the method based on semi- N -body simulation could reach high accuracy (1 per cent level) at small scales, i.e. r  〈 25 h –1 Mpc or k  〉 0.15 h Mpc –1 . Full N -body solutions will remain indispensable to produce reference catalogues. Nevertheless, we have demonstrated that the more efficient approximate solvers can reach a few per cent accuracy in terms of clustering statistics at the scales interesting for the large-scale structure analysis. This makes them useful for massive production aimed at covariance studies, to scan large parameter spaces, and to estimate uncertainties in data analysis techniques, such as baryon acoustic oscillation reconstruction, redshift distortion measurements, etc.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 3
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    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies (2016)
    Oxford University Press
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    Publication Date: 2016-06-26
    Description: We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line of sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12. The LOWZ sample contains 361 762 galaxies with an effective redshift of z lowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of z cmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations 8 by modelling the redshift-space distortion signal. When the geometrical Alcock–Paczynski effect is also constrained from the same data, we find joint constraints on f 8 , the product of the Hubble constant and the comoving sound horizon at the baryon-drag epoch H ( z ) r s ( z d ), and the angular distance parameter divided by the sound horizon D A ( z )/ r s ( z d ). We find f ( z lowz ) 8 ( z lowz ) = 0.394 ± 0.062, D A ( z lowz )/ r s ( z d ) = 6.35 ± 0.19, H ( z lowz ) r s ( z d ) = (11.41 ± 0.56) 10 3 km s – 1 for the LOWZ sample, and f ( z cmass ) 8 ( z cmass ) = 0.444 ± 0.038, D A ( z cmass )/ r s ( z d ) = 9.42 ± 0.15, H ( z cmass ) r s ( z d ) = (13.92 ± 0.44) 10 3 km s – 1 for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial cold dark matter values, we find f ( z lowz ) 8 ( z lowz ) = 0.485 ± 0.044 and f ( z cmass ) 8 ( z cmass ) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 4
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    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release (2016)
    Oxford University Press
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    Publication Date: 2016-01-16
    Description: We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillation Spectroscopic Survey Final Data Release (BOSS DR11&DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated (6000) 12 288 MultiDark patchy BOSS (DR11) DR12 light cones corresponding to an effective volume of ~192 000 [ h –1 Gpc] 3 (the largest ever simulated volume), including cosmic evolution in the redshift range from 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the halo abundance matching modelling of the BOSS DR11&DR12 galaxy clustering data and on the data themselves. The production follows three steps. First, we apply the patchy code to generate a dark matter field and an object distribution including non-linear stochastic galaxy bias. Secondly, we run the halo/stellar distribution reconstruction hadron code to assign masses to the various objects. This step uses the mass distribution as a function of local density and non-local indicators (i.e. tidal field tensor eigenvalues and relative halo exclusion separation for massive objects) from the reference simulation applied to the corresponding patchy dark matter and galaxy distribution. Finally, we apply the sugar code to build the light cones. The resulting MultiDark patchy mock light cones reproduce the number density, selection function, survey geometry, and in general within 1, for arbitrary stellar mass bins, the power spectrum up to k  = 0.3 h Mpc –1 , the two-point correlation functions down to a few Mpc scales, and the three-point statistics of the BOSS DR11&DR12 galaxy samples.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 5
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    Rapid appearance and local toxicity of amyloid-beta plaques in a mouse model of Alzheimer's disease (2008)
    Nature Publishing Group (NPG)
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    Publication Date: 2008-02-08
    Description: Senile plaques accumulate over the course of decades in the brains of patients with Alzheimer's disease. A fundamental tenet of the amyloid hypothesis of Alzheimer's disease is that the deposition of amyloid-beta precedes and induces the neuronal abnormalities that underlie dementia. This idea has been challenged, however, by the suggestion that alterations in axonal trafficking and morphological abnormalities precede and lead to senile plaques. The role of microglia in accelerating or retarding these processes has been uncertain. To investigate the temporal relation between plaque formation and the changes in local neuritic architecture, we used longitudinal in vivo multiphoton microscopy to sequentially image young APPswe/PS1d9xYFP (B6C3-YFP) transgenic mice. Here we show that plaques form extraordinarily quickly, over 24 h. Within 1-2 days of a new plaque's appearance, microglia are activated and recruited to the site. Progressive neuritic changes ensue, leading to increasingly dysmorphic neurites over the next days to weeks. These data establish plaques as a critical mediator of neuritic pathology.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264491/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264491/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer-Luehmann, Melanie -- Spires-Jones, Tara L -- Prada, Claudia -- Garcia-Alloza, Monica -- de Calignon, Alix -- Rozkalne, Anete -- Koenigsknecht-Talboo, Jessica -- Holtzman, David M -- Bacskai, Brian J -- Hyman, Bradley T -- P30 DK056341/DK/NIDDK NIH HHS/ -- P30 DK056341-07/DK/NIDDK NIH HHS/ -- P30 DK056341-08/DK/NIDDK NIH HHS/ -- R01 AG008487/AG/NIA NIH HHS/ -- R01 AG008487-20/AG/NIA NIH HHS/ -- England -- Nature. 2008 Feb 7;451(7179):720-4. doi: 10.1038/nature06616.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Alzheimer's Disease Research Laboratory, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18256671" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/genetics/metabolism/*pathology ; Amyloid beta-Peptides/genetics/metabolism/*toxicity ; Animals ; Axons/metabolism ; *Disease Models, Animal ; Disease Progression ; Mice ; Mice, Transgenic ; Microglia/metabolism ; Neurites/metabolism/pathology ; Plaque, Amyloid/genetics/metabolism/*pathology ; Time Factors
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 6
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    Fractal analysis of persistence in fluctuation of levels of the Magdalena River (2018)
    Institute of Physics (IOP)
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    Publication Date: 2018-10-26
    Description: The measures of water level in a river contributes to understand the dynamic of the discharge in a specific point of the catchment. With this kind of information, it is possible to predict and study future flooding events. The official entity CORMAGDALENA with support of IDEAM report every two days the water level along the Magdalena River. The Hurst coefficient H generates a new statistic methodology, which is based on the tendencies of data series, determining the persistence a dataset and consequently its fractality. This research applies this methodology to a dataset of time, registered by CORMAGDALENA in the municipality of Barrancabermeja, in the Department of Santander. The time has been taken between September 29 th of 2011 and March 31 st of 2017. According to the value of H we can say if the series of behaviours taken has persistence in the case that H is greater than 0.5, if H is less than 0.5 we will say that the series is anti-persistent. With th...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
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  • 7
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    On the physics of radio haloes in galaxy clusters: scaling relations and luminosity functions (2014)
    Oxford University Press
    Details
    Publication Date: 2014-01-16
    Description: The underlying physics of giant and mini radio haloes in galaxy clusters is still an open question. We find that mini haloes (such as in Perseus and Ophiuchus) can be explained by radio-emitting electrons that are generated in hadronic cosmic ray (CR) interactions with protons of the intracluster medium. By contrast, the hadronic model either fails to explain the extended emission of giant radio haloes (as in Coma at low frequencies) or would require a flat CR profile, which can be realized through outward streaming and diffusion of CRs (in Coma and A2163 at 1.4 GHz). We suggest that a second leptonic component could be responsible for the missing flux in the outer parts of giant haloes within a new hybrid scenario and we describe its possible observational consequences. To study the hadronic emission component of the radio-halo population statistically, we use a cosmological mock galaxy cluster catalogue built from the MultiDark simulation. Because of the properties of CR streaming and the different scalings of the X-ray luminosity ( L X ) and the Sunyaev–Zel'dovich flux ( Y ) with gas density, our model can simultaneously reproduce the observed bimodality of radio-loud and radio-quiet clusters at the same L X as well as the unimodal distribution of radio-halo luminosity versus Y ; thereby suggesting a physical solution to this apparent contradiction. We predict radio-halo emission down to the mass scale of galaxy groups, which highlights the unique prospects for low-frequency radio surveys (such as the Low Frequency Array Tier 1 survey) to increase the number of detected radio haloes by at least an order of magnitude.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 8
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    A phenomenological model for the intracluster medium that matches X-ray and Sunyaev-Zel'dovich observations (2014)
    Oxford University Press
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    Publication Date: 2014-01-16
    Description: Cosmological hydrodynamical simulations of galaxy clusters are still challenged to produce a model for the intracluster medium that matches all aspects of current X-ray and Sunyaev–Zel'dovich observations. To facilitate such comparisons with future simulations and to enable realistic cluster population studies for modelling e.g. non-thermal emission processes, we construct a phenomenological model for the intracluster medium that is based on a representative sample of observed X-ray clusters. We create a mock galaxy cluster catalogue based on the large collisionless N -body simulation MultiDark, by assigning our gas density model to each dark matter cluster halo. Our clusters are classified as cool core and non-cool core according to a dynamical disturbance parameter. We demonstrate that our gas model matches the various observed Sunyaev–Zel'dovich and X-ray scaling relations as well as the X-ray luminosity function, thus enabling to build a reliable mock catalogue for present surveys and forecasts for future experiments. In a companion paper, we apply our catalogues to calculate non-thermal radio and gamma-ray emission of galaxy clusters. We make our cosmologically complete multifrequency mock catalogues for the (non-)thermal cluster emission at different redshifts publicly and freely available online through the MultiDark data base.
    Print ISSN: 0035-8711
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    Topics: Physics
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  • 9
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    Erratum: A phenomenological model for the intracluster medium that matches X-ray and Sunyaev-Zel'dovich observations (2015)
    Oxford University Press
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    Publication Date: 2015-11-11
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 10
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    Erratum: On the physics of radio haloes in galaxy clusters: scaling relations and luminosity functions (2015)
    Oxford University Press
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    Publication Date: 2015-11-11
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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