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Journal articles on the topic 'Hierarchical cosmology'
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1
Oldershaw, Robert L. "Hierarchical cosmology." Astrophysics and Space Science 189, no. 1 (1992): 163–68. http://dx.doi.org/10.1007/bf00642965.
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Kravtsov, Andrey V., and Oleg Y. Gnedin. "Formation of Globular Clusters in Hierarchical Cosmology." Astrophysical Journal 623, no. 2 (April 20, 2005): 650–65. http://dx.doi.org/10.1086/428636.
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Hinton, S. R., T. M. Davis, A. G. Kim, D. Brout, C. B. D’Andrea, R. Kessler, J. Lasker, et al. "Steve: A Hierarchical Bayesian Model for Supernova Cosmology." Astrophysical Journal 876, no. 1 (April 29, 2019): 15. http://dx.doi.org/10.3847/1538-4357/ab13a3.
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Gnedin, Oleg Y., and José L. Prieto. "Dynamical Evolution of Globular Clusters in Hierarchical Cosmology." Proceedings of the International Astronomical Union 3, S246 (September 2007): 403–7. http://dx.doi.org/10.1017/s1743921308016049.
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AbstractWe probe the evolution of globular clusters that could form in giant molecular clouds within high-redshift galaxies. Numerical simulations demonstrate that the large and dense enough gas clouds assemble naturally in current hierarchical models of galaxy formation. These clouds are enriched with heavy elements from earlier stars and could produce star clusters in a similar way to nearby molecular clouds. The masses and sizes of the model clusters are in excellent agreement with the observations of young massive clusters. Do these model clusters evolve into globular clusters that we see in our and external galaxies? In order to study their dynamical evolution, we calculate the orbits of model clusters using the outputs of the cosmological simulation of a Milky Way-sized galaxy. We find that at present the orbits are isotropic in the inner 50 kpc of the Galaxy and preferentially radial at larger distances. All clusters located outside 10 kpc from the center formed in the now-disrupted satellite galaxies. The spatial distribution of model clusters is spheroidal, with a power-law density profile consistent with observations. The combination of two-body scattering, tidal shocks, and stellar evolution results in the evolution of the cluster mass function from an initial power law to the observed log-normal distribution.
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OLDERSHAW, ROBERT L. "QUANTITATIVE SCALING FOR THE SELF-SIMILAR HIERARCHICAL COSMOLOGY." International Journal of General Systems 12, no. 2 (April 1986): 137–48. http://dx.doi.org/10.1080/03081078608934931.
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Prieto, José L., and Oleg Y. Gnedin. "Dynamical Evolution of Globular Clusters in Hierarchical Cosmology." Astrophysical Journal 689, no. 2 (December 20, 2008): 919–35. http://dx.doi.org/10.1086/591777.
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Bouchet, François R., and Lars Hernquist. "Implementation of a Tree Code for Cosmology." Symposium - International Astronomical Union 130 (1988): 563. http://dx.doi.org/10.1017/s0074180900136915.
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We have adapted the Barnes-Hut hierarchical N-body method for cosmological applications. A detailed study of the resulting code yielded the following conclusions: it is SIMPLE, FLEXIBLE, ACCURATE, ROBUST, and EFFICIENT.
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Alfian, Andi. "Evaluating World Religion Paradigm through the Idea of Ultimate Reality." Islam Transformatif : Journal of Islamic Studies 6, no. 1 (July 13, 2022): 63. http://dx.doi.org/10.30983/it.v6i1.5537.
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<p>This study aims to evaluate whether the idea of ultimate reality in world religions contributes to the characteristics of the world religion paradigm, which is hierarchical cosmology or “subject-object cosmology.” Several research on this topic claims that one of the characteristics of the world religion paradigm is its hierarchical perspective. Discussing this issue is important to distinguish the world religions as the paradigm and the world religions as the most widely embraced religion. This study argues that the hierarchical perspective of the world religion paradigm can be rooted in the idea of ultimate reality, that there is a supreme, foremost, and most principal reality in the continuity of this universe, namely the supernatural or God. The hierarchical cosmology consists of three main domains: supernatural/God, culture/human, and nature. This study uses a literature study methodology, relying on books, journals, and texts related to research questions. This study finds that the world religion paradigm or hierarchical cosmology or “subject-object cosmology” is prominent, especially in Abrahamic religions such as Islam, Christianity, and Judaism, even though the concept of ultimate reality in these three religions is different.</p><p align="left"> </p><p><em>Penelitian ini bertujuan untuk mengevaluasi apakah gagasan tentang realitas tertinggi dalam agama-agama dunia turut berkontribusi membentuk karakteristik paradigma agama dunia, yaitu kosmologi hierarkis atau “kosmologi subjek-objek”. Beberapa penelitian tentang topik ini mengklaim bahwa salah satu karakteristik paradigma agama dunia adalah perspektifnya yang hierarkis. Membahas masalah ini penting untuk membedakan agama-agama dunia sebagai paradigma dan agama-agama dunia sebagai agama yang paling banyak dianut. Kajian ini berpendapat bahwa perspektif hierarkis paradigma agama dunia dapat berakar pada gagasan tentang realitas tertinggi, bahwa ada realitas tertinggi, utama, dan paling utama dalam kelangsungan alam semesta ini, yaitu supernatural atau Tuhan. Kosmologi hierarkis terdiri dari tiga domain utama: supernatural/Tuhan, budaya/manusia, dan alam. Penelitian ini menggunakan metodologi studi kepustakaan, dengan mengandalkan buku, jurnal, dan teks-teks yang berkaitan dengan pertanyaan-pertanyaan penelitian. Kajian ini menemukan bahwa paradigma agama dunia atau kosmologi hierarkis atau “kosmologi subjek-objek” menonjol, terutama dalam agama-agama Abrahamik seperti Islam, Kristen, dan Yudaisme, meskipun konsep realitas tertinggi dalam ketiga agama tersebut berbeda. </em></p>
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Anninos, Peter, Michael L. Norman, and David A. Clarke. "Hierarchical numerical cosmology with hydrodynamics: Methods and code tests." Astrophysical Journal 436 (November 1994): 11. http://dx.doi.org/10.1086/174876.
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OLDERSHAW, ROBERT L. "SET THEORY APPLIED TO THE SELF-SIMILAR HIERARCHICAL COSMOLOGY." International Journal of General Systems 10, no. 4 (February 1985): 235–55. http://dx.doi.org/10.1080/03081078508934891.
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Anninos, Peter, and Michael L. Norman. "Hierarchical Numerical Cosmology with Hydrodynamics: Resolving X-Ray Clusters." Astrophysical Journal 459 (March 1996): 12. http://dx.doi.org/10.1086/176865.
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Bolejko, Krzysztof, and Mikołaj Korzyński. "Inhomogeneous cosmology and backreaction: Current status and future prospects." International Journal of Modern Physics D 26, no. 06 (February 9, 2017): 1730011. http://dx.doi.org/10.1142/s0218271817300117.
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Astronomical observations reveal hierarchical structures in the universe, from galaxies, groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales, it seems that some kind of statistical homogeneity can be observed. As a result, modern cosmological models are based on spatially homogeneous and isotropic solutions of the Einstein equations, and the evolution of the universe is approximated by the Friedmann equations. In parallel to standard homogeneous cosmology, the field of inhomogeneous cosmology and backreaction is being developed. This field investigates whether small scale inhomogeneities via nonlinear effects can backreact and alter the properties of the universe on its largest scales, leading to a non-Friedmannian evolution. This paper presents the current status of inhomogeneous cosmology and backreaction. It also discusses future prospects of the field of inhomogeneous cosmology, which is based on a survey of 50 academics working in the field of inhomogeneous cosmology.
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Colantonio, Arturo, Irene Marzoli, Italo Testa, and Emanuella Puddu. "An investigation on conceptual understanding about cosmology." Proceedings of the International Astronomical Union 15, S367 (December 2019): 397–99. http://dx.doi.org/10.1017/s174392132100096x.
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AbstractIn this study, we identify patterns among students beliefs and ideas in cosmology, in order to frame meaningful and more effective teaching activities in this amazing content area. We involve a convenience sample of 432 high school students. We analyze students’ responses to an open-ended questionnaire with a non-hierarchical cluster analysis using the k-means algorithm.
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Mekjian, Aram Z. "Generalized Statistical Models of Voids and Hierarchical Structure in Cosmology." Astrophysical Journal 655, no. 1 (January 20, 2007): 1–10. http://dx.doi.org/10.1086/508151.
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Grujic, Petar. "The concept of fractal cosmos: II Modern cosmology." Serbian Astronomical Journal, no. 165 (2002): 45–65. http://dx.doi.org/10.2298/saj0265045g.
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Development of the concept of fractal cosmos after Anaxagoras has been followed up to the present. It is shown how the concept reappeared in the early Renaissance as a vague idea and subsequently took up a concrete formulation at the beginning of the 20-eth century. The modern cosmology state of affairs has been considered in view of the fractal paradigm and the current disputes and controversies discussed. It is argued that the concept of the hierarchical cosmos is still alive and might become an essential ingredient within the modern view of the universe.
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Payne, Ethan, Ling Sun, Kyle Kremer, Paul D. Lasky, and Eric Thrane. "The Imprint of Superradiance on Hierarchical Black Hole Mergers." Astrophysical Journal 931, no. 2 (May 26, 2022): 79. http://dx.doi.org/10.3847/1538-4357/ac66df.
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Abstract Ultralight bosons are a proposed solution to outstanding problems in cosmology and particle physics: they provide a dark-matter candidate while potentially explaining the strong charge-parity problem. If they exist, ultralight bosons can interact with black holes through the superradiant instability. In this work we explore the consequences of this instability on the evolution of hierarchical black holes within dense stellar clusters. By reducing the spin of individual black holes, superradiance reduces the recoil velocity of merging binary black holes, which, in turn, increases the retention fraction of hierarchical merger remnants. We show that the existence of ultralight bosons with mass 2 × 10−14 ≲ μ/eV ≲ 2 × 10−13 would lead to an increased rate of hierarchical black hole mergers in nuclear star clusters. An ultralight boson in this energy range would result in up to ≈60% more present-day nuclear star clusters supporting hierarchical growth. The presence of an ultralight boson can also double the rate of intermediate-mass black hole mergers to ≈0.08 Gpc−3 yr−1 in the local universe. These results imply that a select range of ultralight boson masses can have far-reaching consequences for the population of black holes in dense stellar environments. Future studies into black hole cluster populations and the spin distribution of hierarchically formed black holes will test this scenario.
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Ribeiro, Marcelo B. "On modeling a relativistic hierarchical (fractal) cosmology by Tolman's spacetime. I - Theory." Astrophysical Journal 388 (March 1992): 1. http://dx.doi.org/10.1086/171123.
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MARFATIA, DANNY. "COSMOLOGY AND HIERARCHY IN STABILIZED RANDALL-SUNDRUM MODELS." International Journal of Modern Physics A 16, supp01c (September 2001): 946–48. http://dx.doi.org/10.1142/s0217751x01008576.
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We consider the cosmology and hierarchy of scales in models with immersed in a five-dimensional curved spacetime subject to radion stabilization. The universe naturally find itself in the radiation-dominated epoch when the inter-brane spacing is static and stable, independent of the form of the stabilizing potential. We recover the standard Friedmann equations without assuming a specific form for the bulk energy-momentum tensor. We address the hierarchy problem in the context of a quartic and exponential stabilizing potential, and find that in either case the presence of a negative tension brane is required and that the string scale can be as low as the electroweak scale. In the situation of self-tuning branes (corresponding to an exponential potential) where the bulk cosmological constant is set to zero, the brane tensions have hierarchical values.
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Ribeiro, Marcelo B. "On Modeling a Relativistic Hierarchical (Fractal) Cosmology by Tolman's Spacetime. III. Numerical Results." Astrophysical Journal 415 (October 1993): 469. http://dx.doi.org/10.1086/173179.
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Lan, Zhiling, Valerie E. Taylor, and Yawei Li. "DistDLB: Improving cosmology SAMR simulations on distributed computing systems through hierarchical load balancing." Journal of Parallel and Distributed Computing 66, no. 5 (May 2006): 716–31. http://dx.doi.org/10.1016/j.jpdc.2006.01.001.
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Cheng (程思浩), Sihao, Yuan-Sen Ting (丁源森), Brice Ménard, and Joan Bruna. "A new approach to observational cosmology using the scattering transform." Monthly Notices of the Royal Astronomical Society 499, no. 4 (October 15, 2020): 5902–14. http://dx.doi.org/10.1093/mnras/staa3165.
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ABSTRACT Parameter estimation with non-Gaussian stochastic fields is a common challenge in astrophysics and cosmology. In this paper, we advocate performing this task using the scattering transform, a statistical tool sharing ideas with convolutional neural networks (CNNs) but requiring neither training nor tuning. It generates a compact set of coefficients, which can be used as robust summary statistics for non-Gaussian information. It is especially suited for fields presenting localized structures and hierarchical clustering, such as the cosmological density field. To demonstrate its power, we apply this estimator to a cosmological parameter inference problem in the context of weak lensing. On simulated convergence maps with realistic noise, the scattering transform outperforms classic estimators and is on a par with the state-of-the-art CNN. It retains advantages of traditional statistical descriptors, has provable stability properties, allows to check for systematics, and importantly, the scattering coefficients are interpretable. It is a powerful and attractive estimator for observational cosmology and the study of physical fields in general.
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Brodie, Jean P., and Aaron Romanowsky. "Kinematics and Angular Momentum in Early Type Galaxy Halos." Proceedings of the International Astronomical Union 11, S317 (August 2015): 190–96. http://dx.doi.org/10.1017/s1743921315010959.
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AbstractWe use the kinematics of discrete tracers, primarily globular clusters (GCs) and planetary nebulae (PNe), along with measurements of the integrated starlight to explore the assembly histories of early type galaxies. Data for GCs and stars are taken from the SLUGGS wide field, 2-dimensional, chemo-dynamical survey (Brodie et al. 2014). Data for PNe are from the PN.S survey (see contributions by Gerhard and by Arnaboldi, this volume). We find widespread evidence for 2-phase galaxy assembly and intriguing constraints on hierarchical merging under a lambda CDM cosmology.
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Murtagh, Fionn. "Hierarchical Matching and Regression with Application to Photometric Redshift Estimation." Proceedings of the International Astronomical Union 12, S325 (October 2016): 145–55. http://dx.doi.org/10.1017/s1743921317001569.
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AbstractThis work emphasizes that heterogeneity, diversity, discontinuity, and discreteness in data is to be exploited in classification and regression problems. A global a priori model may not be desirable. For data analytics in cosmology, this is motivated by the variety of cosmological objects such as elliptical, spiral, active, and merging galaxies at a wide range of redshifts. Our aim is matching and similarity-based analytics that takes account of discrete relationships in the data. The information structure of the data is represented by a hierarchy or tree where the branch structure, rather than just the proximity, is important. The representation is related to p-adic number theory. The clustering or binning of the data values, related to the precision of the measurements, has a central role in this methodology. If used for regression, our approach is a method of cluster-wise regression, generalizing nearest neighbour regression. Both to exemplify this analytics approach, and to demonstrate computational benefits, we address the well-known photometric redshift or ‘photo-z’ problem, seeking to match Sloan Digital Sky Survey (SDSS) spectroscopic and photometric redshifts.
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Bergamini, P., A. Agnello, and G. B. Caminha. "Cluster strong lensing with hierarchical inference." Astronomy & Astrophysics 648 (April 2021): A123. http://dx.doi.org/10.1051/0004-6361/201937138.
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Context. Lensing by galaxy clusters is a versatile probe of cosmology and extragalactic astrophysics, but the accuracy of some of its predictions is limited by the simplified models adopted to reduce the (otherwise intractable) number of degrees of freedom. Aims. We aim to explore cluster lensing models in which the parameters of all cluster member galaxies are free to vary around some common scaling relations with non-zero scatter and deviate significantly from these relations if, and only if, the data require this. Methods. We devised a Bayesian hierarchical inference framework that enables the determination of all lensing parameters and the scaling relation hyperparameters, including intrinsic scatter, from lensing constraints and (if given) stellar kinematic measurements. We achieve this through BAYESLENS, a purpose-built wrapper around common parametric lensing codes that can sample the full posterior on parameters and hyperparameters; we release BAYESLENS with this paper. Results. We ran functional tests of our code against simple mock cluster lensing datasets with realistic uncertainties. The parameters and hyperparameters are recovered within their 68% credibility ranges and the positions of all the “observed” multiple images are accurately reproduced by the BAYELENS best-fit model, without over-fitting. Conclusions. We have shown that an accurate description of cluster member galaxies is attainable, despite a large number of degrees of freedom, through fast and tractable inference. This extends beyond the most updated cluster lensing models. The precise impact on studies of cosmography, galaxy evolution, and high-redshift galaxy populations can then be quantified on real galaxy clusters. While other sources of systematics exist and may be significant in real clusters, our results show that the contribution of intrinsic scatter in cluster member populations can now be controlled.
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Dam, Lawrence. "A probabilistic framework for cosmological inference of peculiar velocities." Monthly Notices of the Royal Astronomical Society 497, no. 2 (July 13, 2020): 1301–19. http://dx.doi.org/10.1093/mnras/staa2040.
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ABSTRACT We present a Bayesian hierarchical framework for a principled data analysis pipeline of peculiar velocity surveys, which makes explicit the inference problem of constraining cosmological parameters from redshift-independent distance indicators. We demonstrate our method for a Fundamental Plane (FP)-based survey. The essence of our approach is to work closely with observables (e.g. angular size, surface brightness, redshift, etc.), through which we bypass the use of summary statistics by working with the probability distributions. The hierarchical approach improves upon the usual analysis in several ways. In particular, it allows a consistent analysis without having to make prior assumptions about cosmology during the calibration phase. Moreover, calibration uncertainties are correctly accounted for in parameter estimation. Results are presented for a new, fully analytic posterior marginalized over all latent variables, which we expect to allow for more principled analyses in upcoming surveys. A maximum a posteriori estimator is also given for peculiar velocities derived from FP data.
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Rubin, David, G. Aldering, P. Antilogus, C. Aragon, S. Bailey, C. Baltay, S. Bongard, et al. "Uniform Recalibration of Common Spectrophotometry Standard Stars onto the CALSPEC System Using the SuperNova Integral Field Spectrograph." Astrophysical Journal Supplement Series 263, no. 1 (October 21, 2022): 1. http://dx.doi.org/10.3847/1538-4365/ac7b7f.
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Abstract We calibrate spectrophotometric optical spectra of 32 stars commonly used as standard stars, referenced to 14 stars already on the Hubble Space Telescope–based CALSPEC flux system. Observations of CALSPEC and non-CALSPEC stars were obtained with the SuperNova Integral Field Spectrograph over the wavelength range 3300–9400 Å as calibration for the Nearby Supernova Factory cosmology experiment. In total, this analysis used 4289 standard-star spectra taken on photometric nights. As a modern cosmology analysis, all presubmission methodological decisions were made with the flux scale and external comparison results blinded. The large number of spectra per star allows us to treat the wavelength-by-wavelength calibration for all nights simultaneously with a Bayesian hierarchical model, thereby enabling a consistent treatment of the Type Ia supernova cosmology analysis and the calibration on which it critically relies. We determine the typical per-observation repeatability (median 14 mmag for exposures ≳5 s), the Maunakea atmospheric transmission distribution (median dispersion of 7 mmag with uncertainty 1 mmag), and the scatter internal to our CALSPEC reference stars (median of 8 mmag). We also check our standards against literature filter photometry, finding generally good agreement over the full 12 mag range. Overall, the mean of our system is calibrated to the mean of CALSPEC at the level of ∼3 mmag. With our large number of observations, careful cross-checks, and 14 reference stars, our results are the best calibration yet achieved with an integral-field spectrograph, and among the best calibrated surveys.
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Umbu Deta, Krisharyanto. "Marapu Resisting the Corporation to Protect the Land." Satya Widya: Jurnal Studi Agama 4, no. 2 (December 31, 2021): 50–66. http://dx.doi.org/10.33363/swjsa.v4i2.765.
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The establishment of a sugar cane plantation in East Sumba has evoked conflicts and resistance from the local people. The damage to the katoda (sites to perform rituals) portrays one of the other violations causing environmental, cultural, and social damages related to the manipulation of customary land and criminalization of local people. This paper aims to discuss this conflict by accentuating, and also promoting, the paradigm of indigenous religion as a tool to understand the resistance of the Marapu community to protect their land. Indigenous Religion Paradigm implies the inter-subjective relationship between human person and non-human person (nature) in the non-hierarchical cosmology, which carries the commitments of responsibility, ethics, and reciprocity. By using this perspective, this work shows the opposite perspectives of the partnership between the corporation and the local government concerning the economic considerations and Marapu community who maintains their inter-subjective cosmology as opposed to the modern economic view. The land is understood differently by each of them. While the former only grasps the monetary side of the land, the latter religiously perceives the land as sources of life for both human and non-human person and, therefore, protects their land as the commitment to be responsible, ethical, and reciprocal.
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Garrity-Bond, Cynthia. "Ecofeminist Epistemology in Vandana Shiva’s The Feminine Principle of Prakriti and Ivone Gebara’s Trinitarian Cosmology." Feminist Theology 26, no. 2 (January 2018): 185–94. http://dx.doi.org/10.1177/0966735017738660.
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The ecofeminist cosmologies of Indian scientist Vandana Shiva and Catholic theologian Ivone Gebara are examined. At the centre of each author’s discourse is their feminist epistemology that occasion a new way of knowing, incorporating each thinker’s social locations as nexus for authority. For Shiva, the feminine principle of Prakriti, or the awareness of nature as a living, interdependent force, is realized through the inclusion of women as sources of expertise and knowledge. Gebara rejects classical theology and philosophy as androcentric, anthropocentric, and hierarchical. Instead Gebara envisions a revised epistemology of inclusivity with emphasis on multiplicity and unity initiated by an ecofeminist Trinitarian cosmology. Taken together Shiva and Gebara provide an epistemology that privileges the paradox of unity through diversity and difference as a solution to society’s current ecological crises.
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Suzuki, Takeru K., and Susumu Inoue. "Cosmic Ray Production of 6Li by Virialisation Shocks in the Early Milky Way." Publications of the Astronomical Society of Australia 21, no. 2 (2004): 148–52. http://dx.doi.org/10.1071/as04026.
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AbstractThe energy dissipated by virialisation shocks during hierarchical structure formation of the Galaxy can exceed that injected by concomitant supernova (SN) explosions. Cosmic rays (CRs) accelerated by such shocks may therefore dominate over SNe in the production of 6Li through α + α fusion without co-producing Be and B. This process can give a more natural account of the observed 6Li abundance in metal-poor stars compared to standard SN CR scenarios. Future searches for correlations between the 6Li abundance and the kinematic properties of halo stars may constitute an important probe of how the Galaxy and its halo formed. Furthermore, 6Li may offer interesting clues to some fundamental but currently unresolved issues in cosmology and structure formation on sub-galactic scales.
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Arshakian, Tigran G., Rainer Beck, Marita Krause, and Dimitry Sokoloff. "Testing the cosmological evolution of magnetic fields in galaxies with the SKA." Proceedings of the International Astronomical Union 4, S259 (November 2008): 667–68. http://dx.doi.org/10.1017/s1743921309031512.
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AbstractWe investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies at high redshifts. Results from simulations of hierarchical structure formation cosmology provide a tool to develop an evolutionary model of regular magnetic fields coupled to galaxy formation and evolution. Turbulence in protogalactic halos generated by thermal virialization can drive an efficient turbulent dynamo. The mean-field dynamo theory is used to derive the timescales of amplification and ordering of regular magnetic fields in disk and dwarf galaxies. For future observations with the SKA, we predict an anticorrelation at fixed redshift between galaxy size and the ratio between ordering scale and galaxy size. Undisturbed dwarf galaxies should host fully coherent fields at z < 1, spiral galaxies at z < 0.5.
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UGGLA, CLAES. "SPACETIME SINGULARITIES: RECENT DEVELOPMENTS." International Journal of Modern Physics D 22, no. 03 (March 2013): 1330002. http://dx.doi.org/10.1142/s0218271813300024.
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Recent developments concerning oscillatory spacelike singularities in general relativity are taking place on two fronts. The first treats generic singularities in spatially homogeneous cosmology, most notably Bianchi types VIII and IX. The second deals with generic oscillatory singularities in inhomogeneous cosmologies, especially those with two commuting spacelike Killing vectors. This paper describes recent progress in these two areas: in the spatially homogeneous case, focus is on mathematically rigorous results, while analytical and numerical results concerning generic behavior and so-called recurring spike formation are the main topics in the inhomogeneous case. Unifying themes are connections between asymptotic behavior, hierarchical structures and solution generating techniques, which provide hints for a link between the nature of generic singularities and a hierarchy of hidden asymptotic symmetries.
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Okamoto, Takashi, and Masahiro Nagashima. "Environmental Effects on Evolution of Cluster Galaxies." Symposium - International Astronomical Union 208 (2003): 435–36. http://dx.doi.org/10.1017/s0074180900207638.
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Using a combination of a cosmological N-body simulation and a semi-analytic galaxy formation model, we investigate environmental effects on cluster galaxies with the ACDM cosmology. We find that stripping of hot gas from galacitc halos as they infall into larger objects sufficiently suppresses star formation in the cluster and successfully reproduces the observed gradients of SFR when we normalize our model to reproduce the observed properties of local galaxies. Consequently, the effect of ram-pressure stripping of cold gas from galactic disks becomes quite small and it is observationally negligible. Therefore, the deficiency of galaxies with intermediate bulge-to-disk luminosity ratios under the hierarchical structure formation cannot be resolved even if we include the ram-pressure stripping in our modeling.
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Leistedt, Boris, Justin Alsing, Hiranya Peiris, Daniel Mortlock, and Joel Leja. "Hierarchical Bayesian Inference of Photometric Redshifts with Stellar Population Synthesis Models." Astrophysical Journal Supplement Series 264, no. 1 (January 1, 2023): 23. http://dx.doi.org/10.3847/1538-4365/ac9d99.
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Abstract We present a Bayesian hierarchical framework to analyze photometric galaxy survey data with stellar population synthesis (SPS) models. Our method couples robust modeling of spectral energy distributions with a population model and a noise model to characterize the statistical properties of the galaxy populations and real observations, respectively. By self-consistently inferring all model parameters, from high-level hyperparameters to SPS parameters of individual galaxies, one can separate sources of bias and uncertainty in the data. We demonstrate the strengths and flexibility of this approach by deriving accurate photometric redshifts for a sample of spectroscopically confirmed galaxies in the COSMOS field, all with 26-band photometry and spectroscopic redshifts. We achieve a performance competitive with publicly released photometric redshift catalogs based on the same data. Prior to this work, this approach was computationally intractable in practice due to the heavy computational load of SPS model calls; we overcome this challenge by the addition of neural emulators. We find that the largest photometric residuals are associated with poor calibration for emission-line luminosities and thus build a framework to mitigate these effects. This combination of physics-based modeling accelerated with machine learning paves the path toward meeting the stringent requirements on the accuracy of photometric redshift estimation imposed by upcoming cosmological surveys. The approach also has the potential to create new links between cosmology and galaxy evolution through the analysis of photometric data sets.
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Tadd, Misha. "Ziran: Authenticity or Authority?" Religions 10, no. 3 (March 18, 2019): 207. http://dx.doi.org/10.3390/rel10030207.
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This essay explores the core Daoist concept of ziran (commonly translated as spontaneity, naturalness, or self-so) and its relationship to authenticity and authority. Modern scholarship has often followed the interpretation of Guo Xiang (d. 312) in taking ziran as spontaneous individual authenticity completely unreliant on any external authority. This form of Daoism emphasizes natural transformations and egalitarian society. Here, the author draws on Heshanggong’s Commentary on the Daodejing to reveal a drastically dissimilar ziran conception based on the authority of the transcendent Way. The logic of this contrasting view of classical Daoism results not only in a vision of hierarchical society, but one where the ultimate state of human ziran becomes immortality. Expanding our sense of the Daodejing, this cosmology of authority helps unearths greater continuity of the text with Daoism’s later religious forms.
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Bertelsen, Bjørn Enge. "Egalitarian Lives and Violence." Social Analysis 66, no. 3 (September 1, 2022): 104–25. http://dx.doi.org/10.3167/sa.2022.660306.
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Abstract Since independence in 1975, Mozambique has experimented with society-state relations, including an Afro-socialist revolutionary transformation followed by a multi-party democracy with nominal state functions, such as policing. Building on fieldwork, this article analyzes the genealogy and practices of community policing, arguing that while its emergence reflects a global transformation of state apparatuses reliant on securitization, this transition is still in progress. Community policing practices interconnect with both (petty and organized) crime and nominally past experiments in revolutionary citizenship in socialist Mozambique, including the promises of egalitarian life that linger on in political cosmology and memory. Mozambican community policing thus exhibits the core characteristics of a fluid and ‘predatory-protective’ security assemblage, while simultaneously harboring the potential for instantiating forms of egalitarian life beyond hierarchical state ordering.
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Ribeiro, Marcelo B. "On modeling a relativistic hierarchical (fractal) cosmology by Tolman's spacetime. II - Analysis of the Einstein-de Sitter model." Astrophysical Journal 395 (August 1992): 29. http://dx.doi.org/10.1086/171628.
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Leclercq, Florent, and Alan Heavens. "On the accuracy and precision of correlation functions and field-level inference in cosmology." Monthly Notices of the Royal Astronomical Society: Letters 506, no. 1 (July 20, 2021): L85—L90. http://dx.doi.org/10.1093/mnrasl/slab081.
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ABSTRACT We present a comparative study of the accuracy and precision of correlation function methods and full-field inference in cosmological data analysis. To do so, we examine a Bayesian hierarchical model that predicts lognormal (LN) fields and their two-point correlation function. Although a simplified analytic model, the LN model produces fields that share many of the essential characteristics of the present-day non-Gaussian cosmological density fields. We use three different statistical techniques: (i) a standard likelihood-based analysis of the two-point correlation function; (ii) a likelihood-free (simulation-based) analysis of the two-point correlation function; (iii) a field-level analysis, made possible by the more sophisticated data assimilation technique. We find that (a) standard assumptions made to write down a likelihood for correlation functions can cause significant biases, a problem that is alleviated with simulation-based inference; and (b) analysing the entire field offers considerable advantages over correlation functions, through higher accuracy, higher precision, or both. The gains depend on the degree of non-Gaussianity, but in all cases, including for weak non-Gaussianity, the advantage of analysing the full field is substantial.
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Käfer, Florian, Alexis Finoguenov, Dominique Eckert, Jeremy S. Sanders, Thomas H. Reiprich, and Kirpal Nandra. "Toward a characterization of X-ray galaxy clusters for cosmology." Astronomy & Astrophysics 628 (August 2019): A43. http://dx.doi.org/10.1051/0004-6361/201935124.
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Context. In the framework of the hierarchical model the intra-cluster medium properties of galaxy clusters are tightly linked to structure formation, which makes X-ray surveys well suited for cosmological studies. To constrain cosmological parameters accurately by use of galaxy clusters in current and future X-ray surveys, a better understanding of selection effects related to the detection method of clusters is needed. Aims. We aim at a better understanding of the morphology of galaxy clusters to include corrections between the different core types and covariances with X-ray luminosities in selection functions. In particular, we stress the morphological deviations between a newly described surface brightness profile characterization and a commonly used single β-model. Methods. We investigated a novel approach to describe surface brightness profiles, where the excess cool-core emission in the centers of the galaxy clusters is modeled using wavelet decomposition. Morphological parameters and the residuals were compared to classical single β-models, fitted to the overall surface brightness profiles. Results. Using single β-models to describe the ensemble of overall surface brightness profiles leads on average to a non-zero bias (0.032 ± 0.003) in the outer part of the clusters, that is an approximate 3% systematic difference in the surface brightness at large radii. Furthermore, β-models show a general trend toward underestimating the flux in the outskirts for smaller core radii. Fixing the β parameter to 2/3 doubles the bias and increases the residuals from a single β-model up to more than 40%. Modeling the core region in the fitting procedure reduces the impact of these two effects significantly. In addition, we find a positive scaling between shape parameters and temperature, as well as a negative correlation of approximately −0.4 between extent and luminosity. Conclusion. We demonstrate the caveats in modeling galaxy clusters with single β-models and recommend using them with caution, especially when the systematics are not taken into account. Our non-parametric analysis of the self-similar scaled emission measure profiles indicates no systematic core-type differences of median profiles in the galaxy cluster outskirts.
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Haslbauer, Moritz, Indranil Banik, Pavel Kroupa, Nils Wittenburg, and Behnam Javanmardi. "The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology." Astrophysical Journal 925, no. 2 (February 1, 2022): 183. http://dx.doi.org/10.3847/1538-4357/ac46ac.
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Abstract Any viable cosmological framework has to match the observed proportion of early- and late-type galaxies. In this contribution, we focus on the distribution of galaxy morphological types in the standard model of cosmology (Lambda cold dark matter, ΛCDM). Using the latest state-of-the-art cosmological ΛCDM simulations known as Illustris, IllustrisTNG, and EAGLE, we calculate the intrinsic and sky-projected aspect ratio distribution of the stars in subhalos with stellar mass M * > 1010 M ⊙ at redshift z = 0. There is a significant deficit of intrinsically thin disk galaxies, which however comprise most of the locally observed galaxy population. Consequently, the sky-projected aspect ratio distribution produced by these ΛCDM simulations disagrees with the Galaxy And Mass Assembly (GAMA) survey and Sloan Digital Sky Survey at ≥12.52σ (TNG50-1) and ≥14.82σ (EAGLE50) confidence. The deficit of intrinsically thin galaxies could be due to a much less hierarchical merger-driven build-up of observed galaxies than is given by the ΛCDM framework. It might also arise from the implemented sub-grid models, or from the limited resolution of the above-mentioned hydrodynamical simulations. We estimate that an 85 times better mass resolution realization than TNG50-1 would reduce the tension with GAMA to the 5.58σ level. Finally, we show that galaxies with fewer major mergers have a somewhat thinner aspect ratio distribution. Given also the high expected frequency of minor mergers in ΛCDM, the problem may be due to minor mergers. In this case, the angular momentum problem could be alleviated in Milgromian dynamics because of a reduced merger frequency arising from the absence of dynamical friction between extended dark matter halos.
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McCauley, Joseph L. "The Galaxy Distribution." Fractals 06, no. 02 (June 1998): 109–19. http://dx.doi.org/10.1142/s0218348x98000134.
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From the standpoint of theoretical physics we can treat Newtonian cosmology as a problem in nonlinear dynamics. The attempt to average the density, in search of a method of making contact between theory and observation, is replaced by the more systematic idea of coarsegraining. I also explain in this context why two previous attempts at the construction of hierarchical models of the universe are not useful for data analysis. The main ideas behind two older competing data analyses purporting to show evidence from galaxy statistics for either a homogeneous and isotropic universe in one case, and for a mono-fractal universe in the other, are presented and discussed. I also present the method and results of a newer data analysis that shows that visible matter provides no evidence that would allow us to claim that the cosmological principle holds, or that the universe is fractal (or multifractal). In other words, observational data provides us with no evidence that the universe is either homogeneous and isotropic, or monofractal.
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Mandel, Kaisey S., Stephen Thorp, Gautham Narayan, Andrew S. Friedman, and Arturo Avelino. "A hierarchical Bayesian SED model for Type Ia supernovae in the optical to near-infrared." Monthly Notices of the Royal Astronomical Society 510, no. 3 (December 2, 2021): 3939–66. http://dx.doi.org/10.1093/mnras/stab3496.
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ABSTRACT While conventional Type Ia supernova (SN Ia) cosmology analyses rely primarily on rest-frame optical light curves to determine distances, SNe Ia are excellent standard candles in near-infrared (NIR) light, which is significantly less sensitive to dust extinction. An SN Ia spectral energy distribution (SED) model capable of fitting rest-frame NIR observations is necessary to fully leverage current and future SN Ia data sets from ground- and space-based telescopes including HST, LSST, JWST, and RST. We construct a hierarchical Bayesian model for SN Ia SEDs, continuous over time and wavelength, from the optical to NIR (B through H, or $0.35{-}1.8\, \mu$m). We model the SED as a combination of physically distinct host galaxy dust and intrinsic spectral components. The distribution of intrinsic SEDs over time and wavelength is modelled with probabilistic functional principal components and the covariance of residual functions. We train the model on a nearby sample of 79 SNe Ia with joint optical and NIR light curves by sampling the global posterior distribution over dust and intrinsic latent variables, SED components and population hyperparameters. Photometric distances of SNe Ia with NIR data near maximum obtain a total RMS error of 0.10 mag with our BayeSN model, compared to 0.13–0.14 mag with SALT2 and SNooPy for the same sample. Jointly fitting the optical and NIR data of the full sample up to moderate reddening (host E(B − V) < 0.4) for a global host dust law, we find RV = 2.9 ± 0.2, consistent with the Milky Way average.
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Miniati, Francesco, and Andrey Beresnyak. "Self-similar hierarchical energetics in the ICM of massive galaxy clusters." Proceedings of the International Astronomical Union 11, A29B (August 2015): 700. http://dx.doi.org/10.1017/s1743921316006402.
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AbstractMassive galaxy clusters (GC) are filled with a hot, turbulent and magnetised intra-cluster medium (ICM). They are still forming under the action of gravitational instability, which drives supersonic mass accretion flows. These partially dissipate into heat through a complex network of large scale shocks, and partly excite giant turbulent eddies and cascade. Turbulence dissipation not only contributes to heating of the ICM but also amplifies magnetic energy by way of dynamo action. The pattern of gravitational energy turning into kinetic, thermal, turbulent and magnetic is a fundamental feature of GC hydrodynamics but quantitative modelling has remained a challenge. In this contribution we present results from a recent high resolution, fully cosmological numerical simulation of a massive Coma-like galaxy cluster in which the time dependent turbulent motions of the ICM are resolved (Miniati 2014) and their statistical properties are quantified for the first time (Miniati 2015, Beresnyak & Miniati 2015). We combine these results with independent state-of-the art numerical simulations of MHD turbulence (Beresnyak 2012), which shows that in the nonlinear regime of turbulent dynamo (for magnetic Prandtl numbers≳ 1) the growth rate of the magnetic energy corresponds to a fraction CE ≃ 4 − 5 × 10−2 of the turbulent dissipation rate. We thus determine without adjustable parameters the thermal, turbulent and magnetic history of giant GC (Miniati & Beresnyak 2015). We find that the energy components of the ICM are ordered according to a permanent hierarchy, in which the sonic Mach number at the turbulent injection scale is of order unity, the beta of the plasma of order forty and the ratio of turbulent injection scale to Alfvén scale is of order one hundred. These dimensionless numbers remain virtually unaltered throughout the cluster's history, despite evolution of each individual component and the drive towards equipartition of the turbulent dynamo, thus revealing a new type of self-similarity in cosmology. Their specific values, while consistent with current data, indicate that thermal energy dominates the ICM energetics and the turbulent dynamo is always far from saturation, unlike the condition in other familiar astrophysical fluids (stars, interstellar medium of galaxies, compact objects, etc.). In addition, they have important physical meaning as their specific values encodes information about the efficiency of turbulent heating (the fraction of ICM thermal energy produced by turbulent dissipation) and the efficiency of dynamo action in the ICM (CE).
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Zmorzanka, Anna Z. "„Platoński” Marsanes i jego pitagorejski wątek." Vox Patrum 57 (June 15, 2012): 839–51. http://dx.doi.org/10.31743/vp.4177.
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The opening part of this paper presents the influences of Middle-Platonist philosophy discernible in the ontology presupposed in the Marsanes. These are particularly conspicuous in the hierarchical arrangement of reality. At the summit of the Universe there is Invisible God, second in the hierarchy comes Barbelo, the Mind, complete with the world of intellect (identified with Platonic ideas), then follows the Soul and the world of the sense perception, which is the reflection of ideas. The second part contains a discussion of the fragment NHC X 32, 12 - 33, 6. described in the literature as „Pythagorean”. The fragment contains reference to the two eternal principles: monas and dyas, as well as to the ten cosmogonical principles. In this context the question arises as to the relationship of the cosmogony assumed in this fragment and the one presupposed by the author of the Middle- Platonist exposition. Finally, it is concluded, that the Marsanes cosmogony is typical of its period in being a synthesis comprising themes drawn from ontology (and cosmology) of both: Neopythagoreanism and Middle-Platonism.
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Porqueres, Natalia, Alan Heavens, Daniel Mortlock, and Guilhem Lavaux. "Bayesian forward modelling of cosmic shear data." Monthly Notices of the Royal Astronomical Society 502, no. 2 (January 25, 2021): 3035–44. http://dx.doi.org/10.1093/mnras/stab204.
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ABSTRACT We present a Bayesian hierarchical modelling approach to infer the cosmic matter density field, and the lensing and the matter power spectra, from cosmic shear data. This method uses a physical model of cosmic structure formation to infer physically plausible cosmic structures, which accounts for the non-Gaussian features of the gravitationally evolved matter distribution and light-cone effects. We test and validate our framework with realistic simulated shear data, demonstrating that the method recovers the unbiased matter distribution and the correct lensing and matter power spectrum. While the cosmology is fixed in this test, and the method employs a prior power spectrum, we demonstrate that the lensing results are sensitive to the true power spectrum when this differs from the prior. In this case, the density field samples are generated with a power spectrum that deviates from the prior, and the method recovers the true lensing power spectrum. The method also recovers the matter power spectrum across the sky, but as currently implemented, it cannot determine the radial power since isotropy is not imposed. In summary, our method provides physically plausible inference of the dark matter distribution from cosmic shear data, allowing us to extract information beyond the two-point statistics and exploiting the full information content of the cosmological fields.
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Tie, Suk Sien, David H. Weinberg, Paul Martini, Wei Zhu, Sébastien Peirani, Teresita Suarez, and Stéphane Colombi. "UV background fluctuations and three-point correlations in the large-scale clustering of the Lyman α forest." Monthly Notices of the Royal Astronomical Society 487, no. 4 (June 18, 2019): 5346–62. http://dx.doi.org/10.1093/mnras/stz1632.
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ABSTRACT Using the Lyman α (Lyα) Mass Association Scheme, we make theoretical predictions for the three-dimensional three-point correlation function (3PCF) of the Lyα forest at redshift z = 2.3. We bootstrap results from the (100 h−1 Mpc)3 Horizon hydrodynamic simulation to a (1 h−1 Gpc)3N-body simulation, considering both a uniform ultraviolet background (UVB) and a fluctuating UVB sourced by quasars with a comoving nq ≈ 10−5h3 Mpc−3 placed either in massive haloes or randomly. On scales of 10–30 h−1 Mpc, the flux 3PCF displays hierarchical scaling with the square of the two-point correlation function (2PCF), but with an unusual value of Q ≡ ζ123/(ξ12ξ13 + ξ12ξ23 + ξ13ξ23) ≈ −4.5 that reflects the low bias of the Lyα forest and the anticorrelation between mass density and transmitted flux. For halo-based quasars and an ionizing photon mean free path of λ = 300 h−1 Mpc comoving, UVB fluctuations moderately depress the 2PCF and 3PCF, with cancelling effects on Q. For λ = 100 or 50 h−1 Mpc, UVB fluctuations substantially boost the 2PCF and 3PCF on large scales, shifting the hierarchical ratio to Q ≈ −3. We scale our simulation results to derive rough estimate of the detectability of the 3PCF in current and future observational data sets for the redshift range z = 2.1–2.6. At r = 10 and 20 h−1 Mpc, we predict a signal-to-noise ratio (SNR) of ∼9 and ∼7, respectively, for both Baryon Oscillation Spectroscopic Survey (BOSS) and extended BOSS (eBOSS), and ∼37 and ∼25 for Dark Energy Spectroscopic Instrument (DESI). At r = 40 h−1 Mpc the predicted SNR is lower by a factor of ∼3–5. Measuring the flux 3PCF would provide a novel test of the conventional paradigm of the Lyα forest and help separate the contributions of UVB fluctuations and density fluctuations to Lyα forest clustering, thereby solidifying its foundation as a tool of precision cosmology.
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Margry, Peter Jan. "Mary’s Reincarnation and the Banality of Salvation: The Millennialist Cultus of the Lady of All Nations/Peoples." Numen 59, no. 5-6 (2012): 486–508. http://dx.doi.org/10.1163/15685276-12341236.
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Abstract This article deals with the transnational Dutch-Canadian apparitional cultus of our Lady of All Nations/Peoples. It analyses how contemporary visionary Catholicism is influenced by religious eclecticism, esotericism, and New Age spiritualities, and how this devotion has shifted into an autonomous millennialist movement. Finding fertile soil in modern societies in socio-economic, political, and religious crisis, and due to the dwindling of existential certainties at the individual level, its ideology of “progressive millennialism” has shown itself to be a successful religious format that mobilizes devotees, even when its deviation brings the movement into conflict with the formal Church. The movement’s prophetic and millennialist views fit into a salvific system of conditionality according to which the visionary, unveiled as the reincarnation of Mary herself, will realize the new millennium if her party will fulfill certain conditions. With its new theology the Quebec movement tries to appropriate the whole Lady cultus as a vehicle for universal salvation. In this way the means for revelation and salvation are taken from the hierarchical ecclesiastical powers-that-be and situated in the “banality” of the everyday life of the reincarnated Mary. In the providential Marie-Paule Giguère, the devotees involved find an appealing prophet who is both Mary and a co-redeeming messiah, and who in the near future is supposed to realize the second millennium, framed in a new, modern cosmology, for all peoples and faiths.
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Jones, Jude. "Being, Belief, Comprehension and Confusion: An Exploration of the Assemblages of English Post-Reformation Parochial Religion." Cambridge Archaeological Journal 27, no. 1 (January 11, 2017): 141–54. http://dx.doi.org/10.1017/s0959774316000603.
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The religious temperature of post-Reformation early modern England was constantly over-heating. Given that Protestant belief was frequently challenged by residual dissent, religious identity of whatever kind was crucial to both individual and parochial cosmological understanding. Hence, the many spatial, sensory, material and performative changes which were visited on parish churches over this period were designed to shape and redirect belief, but could also act to confuse believers. In order to penetrate this mass of religious reaction and response, I employ Assemblage Theory, particularly that of the political theorist, Jane Bennett, whose thinking is currently strongly influential amongst archaeologists. Using her work on the vitality of matter and the importance of the assemblage as a phenomenon containing material, non-material and human components, I apply a selection of her ideas to diagnostic elements of being and belief visible in the religious activities and materiality of the early modern parish church. While I refrain from discussing particular human individuals or groups, my chosen examples are intended to foreground the ontology of early modern parishioners, their perception of their hierarchical status within Anglican cosmology, their territorial conceptions of religious space and the workings of time as seen through the sequential assemblages of monumental tombs. Following Bennett, but departing from the current archaeological concentration on the primacy of materiality, this essay is designed to plug some of the people-shaped holes which are sometimes left unfilled by their surrounding material networks.
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Plaszczynski, S., J. E. Campagne, J. Peloton, and C. Arnault. "Scaling pair count to next galaxy surveys." Monthly Notices of the Royal Astronomical Society 510, no. 2 (December 15, 2021): 3085–97. http://dx.doi.org/10.1093/mnras/stab3640.
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ABSTRACT Counting pairs of galaxies or stars according to their distance is at the core of real-space correlation analyses performed in astrophysics and cosmology. Upcoming galaxy surveys (LSST, Euclid) will measure properties of billions of galaxies challenging our ability to perform such counting in a minute-scale time relevant for the usage of simulations. The problem is only limited by efficient access to the data, hence belongs to the big data category. We use the popular Apache Spark framework to address it and design an efficient high-throughput algorithm to deal with hundreds of millions to billions of input data. To optimize it, we revisit the question of non-hierarchical sphere pixelization based on cube symmetries and develop a new one dubbed the ‘Similar Radius Sphere Pixelization’ (SARSPix) with very close to square pixels. It provides the most adapted indexing over the sphere for all distance-related computations. Using LSST-like fast simulations, we compute autocorrelation functions on tomographic bins containing between a hundred million to one billion data points. In each case, we achieve the construction of a standard pair-distance histogram in about 2 min, using a simple algorithm that is shown to scale, over a moderate number of nodes (16–64). This illustrates the potential of this new techniques in the field of astronomy where data access is becoming the main bottleneck. They can be easily adapted to other use-cases as nearest-neighbours search, catalogue cross-match or cluster finding. The software is publicly available from https://github.com/astrolabsoftware/SparkCorr.
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Gilman, Daniel, Xiaolong Du, Andrew Benson, Simon Birrer, Anna Nierenberg, and Tommaso Treu. "Constraints on the mass–concentration relation of cold dark matter haloes with 11 strong gravitational lenses." Monthly Notices of the Royal Astronomical Society: Letters 492, no. 1 (November 20, 2019): L12—L16. http://dx.doi.org/10.1093/mnrasl/slz173.
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ABSTRACT The mass–concentration relation of dark matter haloes reflects the assembly history of objects in hierarchical structure formation scenarios and depends on fundamental quantities in cosmology such as the slope of the primordial matter power spectrum. This relation is unconstrained by observations on sub-galactic scales. We derive the first measurement of the mass–concentration relation using the image positions and flux ratios from 11 quadruple-image strong gravitational lenses (quads) in the mass range $10^{6}\!-\!10^{10} {\, \mathrm{M}_{\odot }}$, assuming cold dark matter. We model both subhaloes and line-of-sight haloes, finite-size background sources, and marginalize over nuisance parameters describing the lens macromodel. We also marginalize over the logarithmic slope and redshift evolution of the mass–concentration relation, using flat priors that encompass the range of theoretical uncertainty in the literature. At z = 0, we constrain the concentration of $10^{8} \, \mathrm{M}_{\odot }$ haloes $c=12_{-5}^{+6}$ at $68 {{\ \rm per\ cent}}$ CI, and $c=12_{-9}^{+15}$ at $95 {{\ \rm per\ cent}}$ CI. For a $10^{7} {\, \mathrm{M}_{\odot }}$ halo, we obtain $68 {{\ \rm per\ cent}}$ ($95 {{\ \rm per\ cent}}$) constraints $c=15_{-8}^{+9}$ ($c=15_{-11}^{+18}$), while for $10^{9} \, \mathrm{M}_{\odot }$ haloes $c=10_{-4}^{+7}$ ($c=10_{-7}^{+14}$). These results are consistent with the theoretical predictions from mass–concentration relations in the literature and establish strong lensing by galaxies as a powerful probe of halo concentrations on sub-galactic scales across cosmological distance.
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Malz, Alex I., and David W. Hogg. "How to Obtain the Redshift Distribution from Probabilistic Redshift Estimates." Astrophysical Journal 928, no. 2 (March 31, 2022): 127. http://dx.doi.org/10.3847/1538-4357/ac062f.
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Abstract A reliable estimate of the redshift distribution n(z) is crucial for using weak gravitational lensing and large-scale structures of galaxy catalogs to study cosmology. Spectroscopic redshifts for the dim and numerous galaxies of next-generation weak-lensing surveys are expected to be unavailable, making photometric redshift (photo-z) probability density functions (PDFs) the next best alternative for comprehensively encapsulating the nontrivial systematics affecting photo-z point estimation. The established stacked estimator of n(z) avoids reducing photo-z PDFs to point estimates but yields a systematically biased estimate of n(z) that worsens with a decreasing signal-to-noise ratio, the very regime where photo-z PDFs are most necessary. We introduce Cosmological Hierarchical Inference with Probabilistic Photometric Redshifts (CHIPPR), a statistically rigorous probabilistic graphical model of redshift-dependent photometry that correctly propagates the redshift uncertainty information beyond the best-fit estimator of n(z) produced by traditional procedures and is provably the only self-consistent way to recover n(z) from photo-z PDFs. We present the chippr prototype code, noting that the mathematically justifiable approach incurs computational cost. The CHIPPR approach is applicable to any one-point statistic of any random variable, provided the prior probability density used to produce the posteriors is explicitly known; if the prior is implicit, as may be the case for popular photo-z techniques, then the resulting posterior PDFs cannot be used for scientific inference. We therefore recommend that the photo-z community focus on developing methodologies that enable the recovery of photo-z likelihoods with support over all redshifts, either directly or via a known prior probability density.