scholarly journals On the road to per cent accuracy IV: ReACT – computing the non-linear power spectrum beyond ΛCDM

2020 ◽  
Vol 498 (4) ◽  
pp. 4650-4662
Author(s):  
Benjamin Bose ◽  
Matteo Cataneo ◽  
Tilman Tröster ◽  
Qianli Xia ◽  
Catherine Heymans ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Computational Modelling ◽  
Power Spectra ◽  
Gravity Models ◽  
Parameter Inference ◽  
The Public ◽  
The Road ◽  
Non Linear ◽  
On The Road

ABSTRACT To effectively exploit large-scale structure surveys, we depend on accurate and reliable predictions of non-linear cosmological structure formation. Tools for efficient and comprehensive computational modelling are therefore essential to perform cosmological parameter inference analyses. We present the public software package ReACT, demonstrating its capability for the fast and accurate calculation of non-linear power spectra from non-standard physics. We showcase ReACT through a series of analyses on the DGP and f(R) gravity models, adopting LSST-like cosmic shear power spectra. Accurate non-linear modelling with ReACT has the potential to more than double LSST’s constraining power on the f(R) parameter, in contrast to an analysis that is limited to the quasi-linear regime. We find that ReACT is sufficiently robust for the inference of consistent constraints on theories beyond ΛCDM for current and ongoing surveys. With further improvement, particularly in terms of the accuracy of the non-linear ΛCDM power spectrum, ReACT can, in principle, meet the accuracy requirements for future surveys such as Euclid and LSST.

scholarly journals On the road to per cent accuracy – II. Calibration of the non-linear matter power spectrum for arbitrary cosmologies

2019 ◽  
Vol 490 (4) ◽  
pp. 4826-4840 ◽  
Author(s):  
Benjamin Giblin ◽  
Matteo Cataneo ◽  
Ben Moews ◽  
Catherine Heymans
Keyword(s):  
Power Spectrum ◽  
Initial Conditions ◽  
Power Spectra ◽  
Linear Regime ◽  
The Road ◽  
Matter Power Spectrum ◽  
Non Linear ◽  
Standard Cosmological Model ◽  
Massive Neutrinos ◽  
On The Road

ABSTRACT We introduce an emulator approach to predict the non-linear matter power spectrum for broad classes of beyond-ΛCDM cosmologies, using only a suite of ΛCDM N-body simulations. By including a range of suitably modified initial conditions in the simulations, and rescaling the resulting emulator predictions with analytical ‘halo model reactions’, accurate non-linear matter power spectra for general extensions to the standard ΛCDM model can be calculated. We optimize the emulator design by substituting the simulation suite with non-linear predictions from the standard halofit tool. We review the performance of the emulator for artificially generated departures from the standard cosmology as well as for theoretically motivated models, such as f(R) gravity and massive neutrinos. For the majority of cosmologies we have tested, the emulator can reproduce the matter power spectrum with errors ${\lesssim}1{{\ \rm per\ cent}}$ deep into the highly non-linear regime. This work demonstrates that with a well-designed suite of ΛCDM simulations, extensions to the standard cosmological model can be tested in the non-linear regime without any reliance on expensive beyond-ΛCDM simulations.

scholarly journals Power spectrum of halo intrinsic alignments in simulations

2020 ◽  
Vol 501 (1) ◽  
pp. 833-852
Author(s):  
Toshiki Kurita ◽  
Masahiro Takada ◽  
Takahiro Nishimichi ◽  
Ryuichi Takahashi ◽  
Ken Osato ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Cosmological Parameters ◽  
Three Dimensional ◽  
Power Spectra ◽  
Acoustic Oscillations ◽  
Matter Power Spectrum ◽  
Sample Covariance ◽  
Non Linear

ABSTRACT We use a suite of N-body simulations to study intrinsic alignments (IA) of halo shapes with the surrounding large-scale structure in the ΛCDM model. For this purpose, we develop a novel method to measure multipole moments of the three-dimensional power spectrum of the E-mode field of halo shapes with the matter/halo distribution, $P_{\delta E}^{(\ell)}(k)$ (or $P^{(\ell)}_{{\rm h}E}$), and those of the auto-power spectrum of the E-mode, $P^{(\ell)}_{EE}(k)$, based on the E/B-mode decomposition. The IA power spectra have non-vanishing amplitudes over the linear to non-linear scales, and the large-scale amplitudes at k ≲ 0.1 h−1 Mpc are related to the matter power spectrum via a constant coefficient (AIA), similar to the linear bias parameter of galaxy or halo density field. We find that the cross- and auto-power spectra PδE and PEE at non-linear scales, k ≳ 0.1 h−1 Mpc, show different k-dependences relative to the matter power spectrum, suggesting a violation of the non-linear alignment model commonly used to model contaminations of cosmic shear signals. The IA power spectra exhibit baryon acoustic oscillations, and vary with halo samples of different masses, redshifts, and cosmological parameters (Ωm, S8). The cumulative signal-to-noise ratio for the IA power spectra is about 60 per cent of that for the halo density power spectrum, where the super-sample covariance is found to give a significant contribution to the total covariance. Thus our results demonstrate that the IA power spectra of galaxy shapes, measured from imaging and spectroscopic surveys for an overlapping area of the sky, can be used to probe the underlying matter power spectrum, the primordial curvature perturbations, and cosmological parameters, in addition to the standard galaxy density power spectrum.

scholarly journals Green Deal as a Climate Changes Dam on the Road to Health

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Jevtic ◽  
C Bouland
Keyword(s):  
Public Health ◽  
Climate Change ◽  
Circular Economy ◽  
Clinical Medicine ◽  
Health Sector ◽  
The Public ◽  
The Road ◽  
National Public Health ◽  
On The Road ◽  
The Impact

Abstract Public health professionals (PHP) have a dual task in climate change. They should persuade their colleagues in clinical medicine of the importance of all the issues covered by the GD. The fact that the health sector contributes to the overall emissions of 4.4% speaks to the lack of awareness within the health sector itself. The issue of providing adequate infrastructure for the health sector is essential. Strengthening the opportunities and development of the circular economy within healthcare is more than just a current issue. The second task of PHP is targeting the broader population. The public health mission is being implemented, inter alia, through numerous activities related to environmental monitoring and assessment of the impact on health. GD should be a roadmap for priorities and actions in public health, bearing in mind: an ambitious goal of climate neutrality, an insistence on clean, affordable and safe energy, a strategy for a clean and circular economy. GD provides a framework for the development of sustainable and smart transport, the development of green agriculture and policies from field to table. It also insists on biodiversity conservation and protection actions. The pursuit of zero pollution and an environment free of toxic chemicals, as well as incorporating sustainability into all policies, is also an indispensable part of GD. GD represents a leadership step in the global framework towards a healthier future and comprises all the non-EU members as well. The public health sector should consider the GD as an argument for achieving goals at national levels, and align national public health policies with the goals of this document. There is a need for stronger advocacy of health and public-health interests along with incorporating sustainability into all policies. Achieving goals requires the education process for healthcare professionals covering all of topics of climate change, energy and air pollution to a much greater extent than before.

scholarly journals The anisotropy of the power spectrum in periodic cosmological simulations

2021 ◽  
Vol 503 (4) ◽  
pp. 5638-5645
Author(s):  
Gábor Rácz ◽  
István Szapudi ◽  
István Csabai ◽  
László Dobos
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Initial Conditions ◽  
Power Spectra ◽  
Cosmological Simulations ◽  
Spherical Collapse ◽  
Lower Amplitude ◽  
Hydrodynamical Simulations

ABSTRACT The classical gravitational force on a torus is anisotropic and always lower than Newton’s 1/r2 law. We demonstrate the effects of periodicity in dark matter only N-body simulations of spherical collapse and standard Lambda cold dark matter (ΛCDM) initial conditions. Periodic boundary conditions cause an overall negative and anisotropic bias in cosmological simulations of cosmic structure formation. The lower amplitude of power spectra of small periodic simulations is a consequence of the missing large-scale modes and the equally important smaller periodic forces. The effect is most significant when the largest mildly non-linear scales are comparable to the linear size of the simulation box, as often is the case for high-resolution hydrodynamical simulations. Spherical collapse morphs into a shape similar to an octahedron. The anisotropic growth distorts the large-scale ΛCDM dark matter structures. We introduce the direction-dependent power spectrum invariant under the octahedral group of the simulation volume and show that the results break spherical symmetry.

scholarly journals On the road to per cent accuracy – III. Non-linear reaction of the matter power spectrum to massive neutrinos

2019 ◽  
Vol 491 (3) ◽  
pp. 3101-3107 ◽  
Author(s):  
M Cataneo ◽  
J D Emberson ◽  
D Inman ◽  
J Harnois-Déraps ◽  
C Heymans
Keyword(s):  
Power Spectrum ◽  
Cold Dark Matter ◽  
New Physics ◽  
Model Reaction ◽  
Matter Power Spectrum ◽  
Non Linear ◽  
Cent Level ◽  
Massive Neutrinos ◽  
On The Road ◽  
Total Matter

ABSTRACT We analytically model the non-linear effects induced by massive neutrinos on the total matter power spectrum using the halo model reaction framework of Cataneo et al. In this approach, the halo model is used to determine the relative change to the matter power spectrum caused by new physics beyond the concordance cosmology. Using standard fitting functions for the halo abundance and the halo mass–concentration relation, the total matter power spectrum in the presence of massive neutrinos is predicted to per cent-level accuracy, out to $k=10 \,{ h}\,{\rm Mpc}^{-1}$. We find that refining the prescriptions for the halo properties using N-body simulations improves the recovered accuracy to better than 1 per cent. This paper serves as another demonstration for how the halo model reaction framework, in combination with a single suite of standard Λ cold dark matter (ΛCDM) simulations, can recover per cent-level accurate predictions for beyond ΛCDM matter power spectra, well into the non-linear regime.

scholarly journals Anti-symmetric clustering signals in the observed power spectrum

2021 ◽  
Vol 2021 (12) ◽  
pp. 003
Author(s):  
José Fonseca ◽  
Chris Clarkson
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Euler Equation ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Power Spectra ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Signal To Noise ◽  
Peculiar Velocities

Abstract In this paper, we study how to directly measure the effect of peculiar velocities in the observed angular power spectra. We do this by constructing a new anti-symmetric estimator of Large Scale Structure using different dark matter tracers. We show that the Doppler term is the major component of our estimator and we show that we can measure it with a signal-to-noise ratio up to ∼ 50 using a futuristic SKAO HI galaxy survey. We demonstrate the utility of this estimator by using it to provide constraints on the Euler equation.

scholarly journals Public-Private Partnership for achieving sustainable development goals: a case study of Khulna, Bangladesh

2020 ◽  
Vol 23 (3) ◽  
pp. 283-298
Author(s):  
Md. Nazmul Haque ◽  
Mustafa Saroar ◽  
Md. Abdul Fattah ◽  
Syed Riad Morshed
Keyword(s):  
Sustainable Development ◽  
Sustainable Development Goals ◽  
Public Private Partnership ◽  
Private Partnership ◽  
Content Type ◽  
The Public ◽  
The Road ◽  
Development Goals ◽  
On The Road

PurposePublic-Private Partnership (PPP) is a common practice in both the public and private sectors. PPP has been an important instrument to achieve Sustainable Development Goals (SDGs) at the national level. However, the role of PPP at the subnational level is often scarcely studied. Using Khulna city of Bangladesh as a case, this paper aims to assess the role of PPP projects in the attainment of SDGs.Design/methodology/approachThe research was conducted in the Central Business District (CBD) of Khulna, on a total of 4.6 kilometers stretches of road medians in the CBD where landscaping was done through the PPP approach. Besides the collection of secondary data from official records, primary data were collected through site visits, field surveys and interviews of PPP project partners.FindingsThe result shows that 89 percent of the respondents (road users) were pleased with the landscaping done on the road medians. Similarly, about 86 percent of the respondents felt more comfortable and safer to use the roads. Well-maintained road medians allow road-crossing at a regular interval which reduces the chance of an accident. The private parties have installed promotional billboards on the road medians and saved BDT 10.82 million a year. The public authority saves the maintenance budget amounting to BDT 23 million a year. The project achieves a triple-win situation. Despite some limitations, this PPP project has taken Khulna a step forward to achieve SDGs.Originality/valueThe findings have policy implications as the PPP project has enhanced the resilience of Khulna by addressing the relevant SDGs.

scholarly journals Kinetic field theory: Non-linear cosmic power spectra in the mean-field approximation

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Matthias Bartelmann ◽  
Johannes Dombrowski ◽  
Sara Konrad ◽  
Elena Kozlikin ◽  
Robert Lilow ◽  
...  
Keyword(s):  
Field Theory ◽  
Power Spectrum ◽  
Mean Field ◽  
Power Spectra ◽  
Field Approximation ◽  
Density Fluctuations ◽  
Mean Field Approximation ◽  
Non Linear ◽  
Two Parameters ◽  
Kinetic Field

We use the recently developed Kinetic Field Theory (KFT) for cosmic structure formation to show how non-linear power spectra for cosmic density fluctuations can be calculated in a mean-field approximation to the particle interactions. Our main result is a simple, closed and analytic, approximate expression for this power spectrum. This expression has two parameters characterising non-linear structure growth which can be calibrated within KFT itself. Using this self-calibration, the non-linear power spectrum agrees with results obtained from numerical simulations to within typically \lesssim10\,\%≲10% up to wave numbers k\lesssim10\,h\,\mathrm{Mpc}^{-1}k≲10hMpc−1 at redshift z = 0z=0. Adjusting the two parameters to optimise agreement with numerical simulations, the relative difference to numerical results shrinks to typically \lesssim 5\,\%≲5%. As part of the derivation of our mean-field approximation, we show that the effective interaction potential between dark-matter particles relative to Zel’dovich trajectories is sourced by non-linear cosmic density fluctuations only, and is approximately of Yukawa rather than Newtonian shape.

scholarly journals ALTERNATIF GEDUNG PELATARAN PARKIR UNTUK MENGURANGI KEMACETAN LALU LINTAS PADA JALAN AHMAD YANI DI MEDAN

2018 ◽  
Vol 2 (3) ◽  
pp. 108
Author(s):  
Husni Thamrin
Keyword(s):  
Survey Data ◽  
Public Service ◽  
Average Velocity ◽  
Development Plan ◽  
Level Of Service ◽  
The Public ◽  
The Road ◽  
On The Road ◽  
A Chain ◽  
Service Building

Abstract: congestion on the office and trade areas especially on Jalan Ahmad Yani is not very good. Average velocity of traffic in the morning or afternoon is only about 2 km / h, indicating the level of service on the road in the worst condition. Before getting the solution of the problem, it needs to be identified and planning things that have the potential to avoid such congestion. This study describes the existing conditions, descriptions and analysis of survey data carried out until later will be planned Building Parking Places to overcome this. The building is intended as an effort that serves the users of vehicles in a region section of Medan. It is expected that this Parking Building Building with the surrounding building can support each other. In general, this development plan only serves a particular vehicle, as a chain of facilities provided from vehicle manufacturers. The purpose of the public service is parked as much as possible, this Parking Service Building does not restrict the service only to the area where it is located, the service and placement for parking can come from outside the area in question, that is with related activities around it.Keywords: Parking Field, Vehicle Circulation, Congestion Abstrak: Kemacetan lalu lintas pada kawasan perkantoran dan perdagangan terutama di Jalan Ahmad Yani sudah sangat tidak baik. Rata-rata kecepatan arus kenderaan pada pagi atau siang hari hanya sekitar 2 km/jam, menunjukan tingkat pelayanan di jalan tersebut pada kondisi terburuk. Sebelum mendapatkan solusi dari masalah tersebut, perlu diidentifikasi dan perencanaan hal yang berpotensi untuk menghindari kemacetatan tersebut. Penelitian ini menggambarkan kondisi yang ada, deskripsi dan analisa data survei yang dilakukan sampai nantinya akan direncanakan Gedung Pelataran Parkir untuk mengatasi hal tersebut. Gedung dimaksudkan sebagai usaha yang melayani pemakai kendaraan dalam suatu wilayah dibagian kota Medan. Diharapkan Gedung Pelataran Parkir ini dengan yang  gedung sekitarnya dapat saling menunjang. Pada umumnya rencana pembangunan ini hanya melayani kendaraan tertentu, sebagai mata rantai dari fasilitas yang diberikan dari produsen kendaraan. Tujuan pelayanan masyarakat yang berparkir semaksimal, Gedung Pelataran Parkir ini tidak membatasi pelayanan hanya pada wilayah dimana ia berada, pelayanan dan penempatan untuk parkir dapat datang dari luar wilayah yang dimaksud, yaitu dengan aktivitas-aktivitas yang berhubungan disekitarnya.Kata Kunci: Pelataran Parkir, Sirkulasi Kenderaan, Kemacetan

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