scholarly journals Using GAMA to probe the impact of small-scale galaxy physics on nonlinear redshift-space distortions

2021 ◽  
Author(s):  
Shadab Alam ◽  
John A Peacock ◽  
Daniel J Farrow ◽  
J Loveday ◽  
A M Hopkins
Keyword(s):  
Degrees Of Freedom ◽  
Small Scale ◽  
Mcmc Algorithm ◽  
Peculiar Velocities ◽  
The Galaxy ◽  
Mass Assembly ◽  
Galaxy Populations ◽  
Using Data ◽  
The Impact ◽  
Perturbation Growth

Abstract We present improved modelling of the redshift-space distortions of galaxy clustering that arise from peculiar velocities. We create mock galaxy catalogues in the framework of the halo model, using data from the Bolshoi project. These mock galaxy populations are inserted into the haloes with additional degrees of freedom that govern spatial and kinematical biases of the galaxy populations relative to the dark matter. We explore this generalised halo model with an MCMC algorithm, comparing the predictions to data from the Galaxy And Mass Assembly (GAMA) survey, and thus derive one of the first constraints on the detailed kinematic degrees of freedom for satellite galaxies within haloes. With this approach, the distortions of the redshift-space galaxy autocorrelations can be accounted for down to spatial separations close to 10 kpc, opening the prospect of improved RSD measurements of the perturbation growth rate by the inclusion of data from nonlinear scales.

scholarly journals The halo model as a versatile tool to predict intrinsic alignments

2020 ◽  
Author(s):  
Maria Cristina Fortuna ◽  
Henk Hoekstra ◽  
Benjamin Joachimi ◽  
Harry Johnston ◽  
Nora Elisa Chisari ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Power Spectra ◽  
Stage Iv ◽  
Stage Iii ◽  
Radial Dependence ◽  
Additional Parameter ◽  
Small Scales ◽  
Cosmic Shear ◽  
Galaxy Populations ◽  
The Impact

Abstract Intrinsic alignments (IAs) of galaxies are an important contaminant for cosmic shear studies, but the modelling is complicated by the dependence of the signal on the source galaxy sample. In this paper, we use the halo model formalism to capture this diversity and examine its implications for Stage-III and Stage-IV cosmic shear surveys. We account for the different IA signatures at large and small scales, as well for the different contributions from central/satellite and red/blue galaxies, and we use realistic mocks to account for the characteristics of the galaxy populations as a function of redshift. We inform our model using the most recent observational findings: we include a luminosity dependence at both large and small scales and a radial dependence of the signal within the halo. We predict the impact of the total IA signal on the lensing angular power spectra, including the current uncertainties from the IA best-fits to illustrate the range of possible impact on the lensing signal: the lack of constraints for fainter galaxies is the main source of uncertainty for our predictions of the IA signal. We investigate how well effective models with limited degrees of freedom can account for the complexity of the IA signal. Although these lead to negligible biases for Stage-III surveys, we find that, for Stage-IV surveys, it is essential to at least include an additional parameter to capture the redshift dependence.

scholarly journals Cosmological constraints from galaxy–lensing cross-correlations using BOSS galaxies with SDSS and CMB lensing

2019 ◽  
Vol 491 (1) ◽  
pp. 51-68 ◽  
Author(s):  
Sukhdeep Singh ◽  
Rachel Mandelbaum ◽  
Uroš Seljak ◽  
Sergio Rodríguez-Torres ◽  
Anže Slosar
Keyword(s):  
Cosmological Parameters ◽  
Small Scale ◽  
The Galaxy ◽  
Scale Modelling ◽  
Modelling Uncertainties ◽  
Cent Level ◽  
Cross Correlations ◽  
Galaxy Bias ◽  
The Impact ◽  
Parameter Constraints

ABSTRACT We present cosmological parameter constraints based on a joint modelling of galaxy–lensing cross-correlations and galaxy clustering measurements in the SDSS, marginalizing over small-scale modelling uncertainties using mock galaxy catalogues, without explicit modelling of galaxy bias. We show that our modelling method is robust to the impact of different choices for how galaxies occupy dark matter haloes and to the impact of baryonic physics (at the $\sim 2{{\ \rm per\ cent}}$ level in cosmological parameters) and test for the impact of covariance on the likelihood analysis and of the survey window function on the theory computations. Applying our results to the measurements using galaxy samples from BOSS and lensing measurements using shear from SDSS galaxies and CMB lensing from Planck, with conservative scale cuts, we obtain $S_8\equiv \left(\frac{\sigma _8}{0.8228}\right)^{0.8}\left(\frac{\Omega _\mathrm{ m}}{0.307}\right)^{0.6}=0.85\pm 0.05$ (stat.) using LOWZ × SDSS galaxy lensing, and S8 = 0.91 ± 0.1 (stat.) using combination of LOWZ and CMASS × Planck CMB lensing. We estimate the systematic uncertainty in the galaxy–galaxy lensing measurements to be $\sim 6{{\ \rm per\ cent}}$ (dominated by photometric redshift uncertainties) and in the galaxy–CMB lensing measurements to be $\sim 3{{\ \rm per\ cent}}$, from small-scale modelling uncertainties including baryonic physics.

The impact of domestic water on household enterprises: evidence from Vietnam

Water Policy ◽  
2009 ◽  
Vol 12 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Stacey Noel ◽  
Hoang Thi Phuong ◽  
John Soussan ◽  
Jon C. Lovett
Keyword(s):  
Rural Areas ◽  
Small Scale ◽  
Domestic Water ◽  
Waste Products ◽  
Household Level ◽  
Piped Water ◽  
Poor Households ◽  
Using Data ◽  
The Impact ◽  
Micro Enterprises

A number of rural household-based productive activities, such as kitchen gardens, livestock rearing and micro enterprises, are dependent on adequate supplies of domestic water to operate. This paper examines whether improved access to piped water can facilitate these types of activities, particularly for poor households. Using data from rural Vietnam, we find that most household enterprises use non-metered water and have very small profit margins. Thus, the evidence suggests that these enterprises may be better supported by a household-level water supply infrastructure, such as well pumps and rainwater catchment tanks, rather than by piped systems in rural areas. We also found an unanticipated link between operating small-scale food production businesses and raising livestock: for many households, waste products from food-based micro enterprises were used for rearing pigs, and this enabled business owners to expand their pork production, a significant source of income and prosperity in rural Vietnam.

scholarly journals Large scale profiles of galaxies at z=0-2 studied by stacking the HSC SSP survey data

2016 ◽  
Vol 11 (S321) ◽  
pp. 318-320
Author(s):  
Mariko Kubo ◽  
Masami Ouchi ◽  
Takatoshi Shibuya
Keyword(s):  
Survey Data ◽  
Surface Brightness ◽  
Large Scale ◽  
High Redshift ◽  
Photometric Redshifts ◽  
Early Formation ◽  
The Galaxy ◽  
Strategic Program ◽  
Galaxy Populations ◽  
Using Data

AbstractWe are carrying out the study of the evolution of radial surface brightness profiles of galaxies from z = 0 to 2 by stacking analysis using data corrected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). This will allow us to constrain the large scale average profiles of various galaxy populations at high redshift. From the stacking analysis of galaxies selected based on their photometric redshifts, we successfully detected the outer components of galaxies at z > 1 extending to at least ~80 kpc, which imply an early formation for the galaxy outskirts.

scholarly journals Direct Shear Mapping: Prospects for Weak Lensing Studies of Individual Galaxy–Galaxy Lensing Systems

2015 ◽  
Vol 32 ◽  
Author(s):  
C. O. de Burgh-Day ◽  
E. N. Taylor ◽  
R. L. Webster ◽  
A. M. Hopkins
Keyword(s):  
Weak Lensing ◽  
Mapping Technique ◽  
Direct Shear ◽  
Redshift Galaxy ◽  
The Galaxy ◽  
Redshift Survey ◽  
Mass Assembly ◽  
Using Data ◽  
Spectrally Resolved ◽  
Good Agreement

AbstractUsing both a theoretical and an empirical approach, we have investigated the frequency of low redshift galaxy-galaxy lensing systems in which the signature of 3D weak lensing might be directly detectable. We find good agreement between these two approaches. Using data from the Galaxy and Mass Assembly redshift survey we estimate the frequency of detectable weak lensing at low redshift. We find that below a redshift of z ~ 0.6, the probability of a galaxy being weakly lensed by γ ⩾ 0.02 is ~ 0.01. We have also investigated the feasibility of measuring the scatter in the M* − Mh relation using shear statistics. We estimate that for a shear measurement error of Δγ = 0.02 (consistent with the sensitivity of the Direct Shear Mapping technique), with a sample of ~$50,000 spatially and spectrally resolved galaxies, the scatter in the M* − Mh relation could be measured. While there are currently no existing IFU surveys of this size, there are upcoming surveys that will provide this data (e.g The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), surveys with Hector, and the Square Kilometre Array (SKA)).

scholarly journals The Impact of ISM Turbulence, Clustered Star Formation and Feedback on Galaxy Mass Assembly through Cold Flows and Mergers

2010 ◽  
Vol 6 (S277) ◽  
pp. 234-237
Author(s):  
Leila C. Powell ◽  
Frederic Bournaud ◽  
Damien Chapon ◽  
Julien Devriendt ◽  
Adrianne Slyz ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Equal Mass ◽  
Temperature Threshold ◽  
Galaxy Mergers ◽  
Redshift Galaxy ◽  
Mass Assembly ◽  
Hydrodynamical Simulations ◽  
Galaxy Populations ◽  
The Impact

AbstractTwo of the dominant channels for galaxy mass assembly are cold flows (cold gas supplied via the filaments of the cosmic web) and mergers. How these processes combine in a cosmological setting, at both low and high redshift, to produce the whole zoo of galaxies we observe is largely unknown. Indeed there is still much to understand about the detailed physics of each process in isolation. While these formation channels have been studied using hydrodynamical simulations, here we study their impact on gas properties and star formation (SF) with some of the first from simulations that capture the multiphase, cloudy nature of the interstellar medium (ISM), by virtue of their high spatial resolution (and corresponding low temperature threshold). In this regime, we examine the competition between cold flows and a supernovae(SNe)-driven outflow in a very high-redshift galaxy (z ≈ 9) and study the evolution of equal-mass galaxy mergers at low and high redshift, focusing on the induced SF. We find that SNe-driven outflows cannot reduce the cold accretion at z ≈ 9 and that SF is actually enhanced due to the ensuing metal enrichment. We demonstrate how several recent observational results on galaxy populations (e.g. enhanced HCN/CO ratios in ULIRGs, a separate Kennicutt Schmidt (KS) sequence for starbursts and the population of compact early type galaxies (ETGs) at high redshift) can be explained with mechanisms captured in galaxy merger simulations, provided that the multiphase nature of the ISM is resolved.

scholarly journals The impact of stock collapse on small-scale fishers’ behavior: evidence from Japan

2018 ◽  
Vol 75 (12) ◽  
pp. 2241-2254 ◽  
Author(s):  
Shoichi Kiyama ◽  
Satoshi Yamazaki
Keyword(s):  
Environmental Changes ◽  
Alternative Form ◽  
Small Scale ◽  
Key Species ◽  
Development Policies ◽  
Management And Development ◽  
Declining Species ◽  
Using Data ◽  
Substantial Decline ◽  
The Impact

Understanding behavioral responses of resource users to environmental changes and incentives created by management systems is imperative to implement effective resource management and development policies. A small-scale mixed fishery in the Maizuru Bay, Japan, provides a natural experiment to evaluate changes in small-scale fishers’ harvesting and targeting behavior over the years that one of the key species in the fishery experienced a collapse of the stock. Using data on individual fishers across the pre- and postcollapse periods, we find that inefficient fishers were forced to shut down or stay idle along with the collapse of the stock, and this behavior led to an increase in the overall efficiency in the production of clams (Venerupis philippinarum). The depletion of the stock, however, imposed a natural constraint on the operation, resulting in a substantial decline in the maximum production achievable by the remaining fishers. We further show that the collapse of the stock not only affected the harvesting behavior against the declining species but also led to the expansion of the fishing capacity and effort to catch other species and the development of aquaculture as an alternative form of fish production in the region.

scholarly journals Properties of brightest group galaxies in cosmic web filaments

2020 ◽  
Vol 639 ◽  
pp. A71 ◽  
Author(s):  
Teet Kuutma ◽  
Anup Poudel ◽  
Maret Einasto ◽  
Pekka Heinämäki ◽  
Heidi Lietzen ◽  
...  
Keyword(s):  
Marked Point ◽  
Local Environment ◽  
Marked Point Process ◽  
Galaxy Groups ◽  
Final Sample ◽  
The Galaxy ◽  
Galaxy Sample ◽  
Galaxy Populations ◽  
The Impact ◽  
Main Factor

Context. The cosmic web, a complex network of galaxy groups and clusters connected by filaments, is a dynamical environment in which galaxies form and evolve. However, the impact of cosmic filaments on the properties of galaxies is difficult to study because of the much more influential local (galaxy-group scale) environment. Aims. The aim of this paper is to investigate the dependence of intrinsic galaxy properties on distance to the nearest cosmic web filament, using a sample of galaxies for which the local environment is easily assessable. Methods. Our study is based on a volume-limited galaxy sample with Mr ≤ −19 mag, drawn from the SDSS DR12. We chose brightest group galaxies (BGGs) in groups with two to six members as our probes of the impact of filamentary environment because their local environment can be determined more accurately. We use the Bisous marked point process method to detect cosmic-web filaments with radii of 0.5−1.0 Mpc and measure the perpendicular filament spine distance (Dfil) for the BGGs. We limit our study to Dfil values up to 4 Mpc. We use the luminosity density field as a tracer of the local environment. To achieve uniformity of the sample and to reduce potential biases we only consider filaments longer than 5 Mpc. Our final sample contains 1427 BGGs. Results. We note slight deviations between the galaxy populations inside and outside the filament radius in terms of stellar mass, colour, the 4000 Å break, specific star formation rates, and morphologies. However, all these differences remain below 95% confidence and are negligible compared to the effects arising from local environment density. Conclusions. Within a 4 Mpc radius of the filament axes, the effect of filaments on BGGs is marginal. The local environment is the main factor in determining BGG properties.

scholarly journals ‘Observing’ unrelaxed clusters in dark matter simulations

2019 ◽  
Vol 490 (1) ◽  
pp. 773-783
Author(s):  
Ian D Roberts ◽  
Laura C Parker
Keyword(s):  
Dark Matter ◽  
Recent Work ◽  
Three Dimensional ◽  
Line Of Sight ◽  
One Dimensional ◽  
The Galaxy ◽  
Velocity Information ◽  
Galaxy Populations ◽  
Non Gaussian ◽  
The Impact

ABSTRACT We present a detailed study of relaxed and unrelaxed galaxy clusters in a large dark matter only simulation. Recent work has demonstrated clear differences between the galaxy populations in clusters that have Gaussian velocity distributions (relaxed) compared to those that do not (unrelaxed). To directly compare with observations, we identify unrelaxed clusters in the simulations using one-dimensional velocity distributions. We show that non-Gaussian clusters have had recent major mergers and enhanced rates of galaxy infall relative to systems with Gaussian velocity profiles. Furthermore, we find that the fraction of non-Gaussian clusters increases strongly with cluster mass and modestly with redshift. For comparison, we also make use of three-dimensional information available in the simulations to explore the impact of projection on observational measurements. Differences between Gaussian and non-Gaussian clusters are much stronger when three-dimensional information is considered, which demonstrates that the strength of oberserved trends with cluster dynamics are diluted because observed velocity information is limited to one line-of-sight.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

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