Excursion set theory is a powerful and widely used tool for describing the distribution of dark matter haloes, but it is normally applied with simplifying approximations. We use numerical sampling methods to study the mass functions predicted by the theory without approximations. With a spherical top-hat window and a constant δ = 1.5 threshold, the theory accurately predicts mass functions with the M200 mass definition, both unconditional and conditional, in simulations of a range of matter-dominated cosmologies. For ΛCDM at the present epoch, predictions lie between the M200m and M200c mass functions. In contrast, with the same window function, a nonconstant threshold based on ellipsoidal collapse predicts uniformly too few haloes. This work indicates a new way to simply and accurately evaluate halo mass functions, clustering bias, and assembly histories for a range of cosmologies. We provide a fitting function that accurately represents the predictions of the theory for a wide range of parameters.
{"title":"Accurate halo mass functions from the simplest excursion set theory","authors":"M Sten Delos","doi":"10.1093/mnras/stae141","DOIUrl":"https://doi.org/10.1093/mnras/stae141","url":null,"abstract":"Excursion set theory is a powerful and widely used tool for describing the distribution of dark matter haloes, but it is normally applied with simplifying approximations. We use numerical sampling methods to study the mass functions predicted by the theory without approximations. With a spherical top-hat window and a constant δ = 1.5 threshold, the theory accurately predicts mass functions with the M200 mass definition, both unconditional and conditional, in simulations of a range of matter-dominated cosmologies. For ΛCDM at the present epoch, predictions lie between the M200m and M200c mass functions. In contrast, with the same window function, a nonconstant threshold based on ellipsoidal collapse predicts uniformly too few haloes. This work indicates a new way to simply and accurately evaluate halo mass functions, clustering bias, and assembly histories for a range of cosmologies. We provide a fitting function that accurately represents the predictions of the theory for a wide range of parameters.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"54 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Searches for gravitational waves from compact-binary mergers, which to date have reported ∼100 observations, have previously ignored binaries whose components are both consistent with the mass of neutron stars (1M⊙ to 2M⊙) and have high dimensionless spin >0.05. While previous searches targeted sources that are representative of observed neutron star binaries in the galaxy, it is already known that neutron stars can regularly be spun up to a dimensionless spin of ∼0.4, and in principle reach up to ∼0.7 before breakup would occur. Furthermore, there may be primordial black hole binaries or exotic formation mechanisms to produce light black holes. In these cases, it is possible for the binary constituent to be spun up beyond that achievable by a neutron star. A single detection of this type of source would reveal a novel formation channel for compact-binaries. To determine if there is evidence for any such sources, we use PyCBC to conduct a targeted search of LIGO and Virgo data for light compact objects with high spin. Our analysis detects previously known observations GW170817 and GW200115; however, we report no additional mergers. The most significant candidate, not previously known, is consistent with the noise distribution, and so we constrain the merger rate of spinning light binaries.
{"title":"Targeted search for gravitational waves from highly spinning light compact binaries","authors":"Yi-Fan Wang, Alexander H Nitz","doi":"10.1093/mnras/stae091","DOIUrl":"https://doi.org/10.1093/mnras/stae091","url":null,"abstract":"Searches for gravitational waves from compact-binary mergers, which to date have reported ∼100 observations, have previously ignored binaries whose components are both consistent with the mass of neutron stars (1M⊙ to 2M⊙) and have high dimensionless spin >0.05. While previous searches targeted sources that are representative of observed neutron star binaries in the galaxy, it is already known that neutron stars can regularly be spun up to a dimensionless spin of ∼0.4, and in principle reach up to ∼0.7 before breakup would occur. Furthermore, there may be primordial black hole binaries or exotic formation mechanisms to produce light black holes. In these cases, it is possible for the binary constituent to be spun up beyond that achievable by a neutron star. A single detection of this type of source would reveal a novel formation channel for compact-binaries. To determine if there is evidence for any such sources, we use PyCBC to conduct a targeted search of LIGO and Virgo data for light compact objects with high spin. Our analysis detects previously known observations GW170817 and GW200115; however, we report no additional mergers. The most significant candidate, not previously known, is consistent with the noise distribution, and so we constrain the merger rate of spinning light binaries.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"20 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Da-Ming Yang, Jan-Torge Schindler, Riccardo Nanni, Joseph F Hennawi, Eduardo Bañados, Xiaohui Fan, Anniek Gloudemans, Chiara Mazzucchelli, Huub Rottgering, Bram Venemans, Feige Wang, Jinyi Yang
We present the high-z quasar candidate archive (HzQCA), summarizing the spectroscopic observations of 207 z ≳ 5 quasar candidates using Keck/LRIS, Keck/MOSFIRE, and Keck/NIRES. We identify 14 candidates as z ∼ 6 quasars, with 10 of them newly reported here, and 63 candidates as brown dwarfs. In the remaining sources, 79 candidates are unlikely to be quasars; 2 sources are inconclusive; the others could not be fully reduced or extracted. Based on the classifications we investigate the distributions of quasars and contaminants in color space with photometry measurements from DELS (z), VIKING/UKIDSS (YJHKs/YJHK), and unWISE (W1W2). We find that the identified brown dwarfs are consistent with the empirical brown dwarf model that is commonly used in quasar candidate selection methods. To refine spectroscopic confirmation strategies, we simulate synthetic spectroscopy of high-z quasars and contaminants for all three instruments. The simulations utilize the spectroscopic data in HzQCA. We predict the required exposure times for quasar confirmation and propose an optimal strategy for spectroscopic follow-up observations. For instance, we demonstrate that we can identify a mJ = 21.5 at z = 7.6 or a mJ = 23.0 at z = 7.0 within 15 min of exposure time with LRIS. With the publication of the HzQCA we aim to provide guidance for future quasar surveys and candidate classification.
我们介绍了高兹类星体候选者档案（HzQCA），总结了利用 Keck/LRIS、Keck/MOSFIRE 和 Keck/NIRES 对 207 个 z ∼ 5 类星体候选者的光谱观测结果。我们确定 14 个候选者为 z ∼ 6 类星，其中 10 个是本文新报道的，63 个候选者为褐矮星。在其余的来源中，有 79 个候选者不太可能是类星体；2 个来源没有定论；其他来源无法完全缩小或提取。根据这些分类，我们利用 DELS (z)、VIKING/UKIDSS (YJHKs/YJHK)和 unWISE (W1W2)的光度测量数据，研究了类星体和污染物在色彩空间的分布情况。我们发现这些被识别的褐矮星与类星体候选者选择方法中常用的经验褐矮星模型是一致的。为了完善光谱确认策略，我们模拟了所有三种仪器的高 z 类星体和污染物的合成光谱。模拟利用了 HzQCA 中的光谱数据。我们预测了类星体确认所需的曝光时间，并提出了光谱跟踪观测的最佳策略。例如，我们证明了利用 LRIS 可以在 15 分钟的曝光时间内确认 z = 7.6 的 mJ = 21.5 或 z = 7.0 的 mJ = 23.0。随着 HzQCA 的发布，我们的目标是为未来的类星体测量和候选天体分类提供指导。
{"title":"High-z Quasar Candidate Archive: A Spectroscopic Catalog of Quasars and Contaminants in Various Quasar Searches","authors":"Da-Ming Yang, Jan-Torge Schindler, Riccardo Nanni, Joseph F Hennawi, Eduardo Bañados, Xiaohui Fan, Anniek Gloudemans, Chiara Mazzucchelli, Huub Rottgering, Bram Venemans, Feige Wang, Jinyi Yang","doi":"10.1093/mnras/stae094","DOIUrl":"https://doi.org/10.1093/mnras/stae094","url":null,"abstract":"We present the high-z quasar candidate archive (HzQCA), summarizing the spectroscopic observations of 207 z ≳ 5 quasar candidates using Keck/LRIS, Keck/MOSFIRE, and Keck/NIRES. We identify 14 candidates as z ∼ 6 quasars, with 10 of them newly reported here, and 63 candidates as brown dwarfs. In the remaining sources, 79 candidates are unlikely to be quasars; 2 sources are inconclusive; the others could not be fully reduced or extracted. Based on the classifications we investigate the distributions of quasars and contaminants in color space with photometry measurements from DELS (z), VIKING/UKIDSS (YJHKs/YJHK), and unWISE (W1W2). We find that the identified brown dwarfs are consistent with the empirical brown dwarf model that is commonly used in quasar candidate selection methods. To refine spectroscopic confirmation strategies, we simulate synthetic spectroscopy of high-z quasars and contaminants for all three instruments. The simulations utilize the spectroscopic data in HzQCA. We predict the required exposure times for quasar confirmation and propose an optimal strategy for spectroscopic follow-up observations. For instance, we demonstrate that we can identify a mJ = 21.5 at z = 7.6 or a mJ = 23.0 at z = 7.0 within 15 min of exposure time with LRIS. With the publication of the HzQCA we aim to provide guidance for future quasar surveys and candidate classification.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"96 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Namu Kroupa, David Yallup, Will Handley, Michael Hobson
Using a fully Bayesian approach, Gaussian Process regression is extended to include marginalisation over the kernel choice and kernel hyperparameters. In addition, Bayesian model comparison via the evidence enables direct kernel comparison. The calculation of the joint posterior was implemented with a transdimensional sampler which simultaneously samples over the discrete kernel choice and their hyperparameters by embedding these in a higher-dimensional space, from which samples are taken using nested sampling. Kernel recovery and mean function inference were explored on synthetic data from exoplanet transit light curve simulations. Subsequently, the method was extended to marginalisation over mean functions and noise models and applied to the inference of the present-day Hubble parameter, H0, from real measurements of the Hubble parameter as a function of redshift, derived from the cosmologically model-independent cosmic chronometer and ΛCDM-dependent baryon acoustic oscillation observations. The inferred H0 values from the cosmic chronometers, baryon acoustic oscillations and combined datasets are H0 = 66 ± 6 km s−1 Mpc−1, H0 = 67 ± 10 km s−1 Mpc−1 and H0 = 69 ± 6 km s−1 Mpc−1, respectively. The kernel posterior of the cosmic chronometers dataset prefers a non-stationary linear kernel. Finally, the datasets are shown to be not in tension with ln R = 12.17 ± 0.02.
利用完全贝叶斯方法，高斯过程回归被扩展到包括核选择和核超参数的边际化。此外，通过证据进行贝叶斯模型比较可以直接进行核比较。联合后验的计算是通过一个跨维采样器来实现的，该采样器通过将离散核选择及其超参数嵌入一个高维空间，同时对其进行采样。在系外行星凌日光变曲线模拟的合成数据上探索了核恢复和均值函数推断。随后，将该方法扩展到均值函数和噪声模型的边际化，并应用于根据独立于宇宙模型的宇宙天文台和独立于Λ CDM 的重子声振荡观测所获得的哈勃参数随红移变化的实际测量值推断现今的哈勃参数 H0。从宇宙天文台、重子声学振荡和综合数据集推断出的 H0 值分别为 H0 = 66 ± 6 km s-1 Mpc-1、H0 = 67 ± 10 km s-1 Mpc-1 和 H0 = 69 ± 6 km s-1 Mpc-1。宇宙计时器数据集的核后验倾向于非稳态线性核。最后，数据集的 ln R = 12.17 ± 0.02 显示并不紧张。
{"title":"Kernel-, mean- and noise-marginalised Gaussian processes for exoplanet transits and H0 inference","authors":"Namu Kroupa, David Yallup, Will Handley, Michael Hobson","doi":"10.1093/mnras/stae087","DOIUrl":"https://doi.org/10.1093/mnras/stae087","url":null,"abstract":"Using a fully Bayesian approach, Gaussian Process regression is extended to include marginalisation over the kernel choice and kernel hyperparameters. In addition, Bayesian model comparison via the evidence enables direct kernel comparison. The calculation of the joint posterior was implemented with a transdimensional sampler which simultaneously samples over the discrete kernel choice and their hyperparameters by embedding these in a higher-dimensional space, from which samples are taken using nested sampling. Kernel recovery and mean function inference were explored on synthetic data from exoplanet transit light curve simulations. Subsequently, the method was extended to marginalisation over mean functions and noise models and applied to the inference of the present-day Hubble parameter, H0, from real measurements of the Hubble parameter as a function of redshift, derived from the cosmologically model-independent cosmic chronometer and ΛCDM-dependent baryon acoustic oscillation observations. The inferred H0 values from the cosmic chronometers, baryon acoustic oscillations and combined datasets are H0 = 66 ± 6 km s−1 Mpc−1, H0 = 67 ± 10 km s−1 Mpc−1 and H0 = 69 ± 6 km s−1 Mpc−1, respectively. The kernel posterior of the cosmic chronometers dataset prefers a non-stationary linear kernel. Finally, the datasets are shown to be not in tension with ln R = 12.17 ± 0.02.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"19 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We demonstrate that the X-ray iron line fitting technique can be leveraged as a powerful probe of the cosmic censorship conjecture. We do this by extending existing emission line models to arbitrary spin parameters of the Kerr metric, no longer restricted to black hole metrics with |a•| < 1. We show that the emission lines from naked singularity metrics (|a•| > 1) show significant differences to their black hole counterparts, even for those metrics with identical locations of the innermost stable circular orbit, i.e., emission line fitting does not suffer from the degeneracy which affects continuum fitting approaches. These differences are entirely attributable to the disappearance of the event horizon for |a•| > 1. We highlight some novel emission line features of naked singularity metrics, such as “inverted” emission lines (with sharp red wings and extended blue wings) and “triple lines”. The lack of detection of any of these novel features provides support of the cosmic censorship conjecture. We publicly release XSPEC packages skline and skconv which can now be used to probe the cosmic censorship conjecture in Galactic X-ray binaries and Active Galactic Nuclei. The inclusion of super-extremal spacetimes can be alternatively posed as a way of stress-testing conventional models of accretion.
{"title":"Reflecting on naked singularities: iron line fitting as a probe of the cosmic censorship conjecture","authors":"Andrew Mummery, Adam Ingram","doi":"10.1093/mnras/stae140","DOIUrl":"https://doi.org/10.1093/mnras/stae140","url":null,"abstract":"We demonstrate that the X-ray iron line fitting technique can be leveraged as a powerful probe of the cosmic censorship conjecture. We do this by extending existing emission line models to arbitrary spin parameters of the Kerr metric, no longer restricted to black hole metrics with |a•| &lt; 1. We show that the emission lines from naked singularity metrics (|a•| &gt; 1) show significant differences to their black hole counterparts, even for those metrics with identical locations of the innermost stable circular orbit, i.e., emission line fitting does not suffer from the degeneracy which affects continuum fitting approaches. These differences are entirely attributable to the disappearance of the event horizon for |a•| &gt; 1. We highlight some novel emission line features of naked singularity metrics, such as “inverted” emission lines (with sharp red wings and extended blue wings) and “triple lines”. The lack of detection of any of these novel features provides support of the cosmic censorship conjecture. We publicly release XSPEC packages skline and skconv which can now be used to probe the cosmic censorship conjecture in Galactic X-ray binaries and Active Galactic Nuclei. The inclusion of super-extremal spacetimes can be alternatively posed as a way of stress-testing conventional models of accretion.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"210 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S Paradiso, M DiMarco, M Chen, G McGee, W J Percival
Despite increasingly precise observations and sophisticated theoretical models, the discrepancy between measurements of H0 from the cosmic microwave background or from Baryon Acoustic Oscillations combined with Big-Bang Nucleosynthesis versus those from local distance ladder probes—commonly known as the ”H0 tension”—continues to perplex the scientific community. To address this tension, Early Dark Energy (EDE) models have been proposed as alternatives to Λ-CDM, as they can change the observed sound horizon and the inferred Hubble constant from measurements based on this. In this paper, we investigate the use of Bayesian Model Averaging (BMA) to evaluate EDE as a solution to the H0 tension. BMA consists of assigning a prior to the model and deriving a posterior as for any other unknown parameter in a Bayesian analysis. BMA can be computationally challenging in that one must approximate the joint posterior of both model and parameters. Here we present a computational strategy for BMA that exploits existing MCMC software and combines model-specific posteriors post-hoc. In application to a comprehensive analysis of cosmological datasets, we quantify the impact of EDE on the H0 discrepancy. We find an EDE model probability of $sim 90%$ whenever we include the H0 measurement from Type Ia Supernovae in the analysis, whereas the other data show a strong preference for the standard cosmological model. We finally present constraints on common parameters marginalized over both cosmological models. For reasonable priors on models with and without EDE, the H0 tension is reduced by at least 20%.
尽管观测越来越精确，理论模型也越来越复杂，但宇宙微波背景或结合大爆炸核合成的重子声学振荡对 H0 的测量结果与本地距离阶梯探测器对 H0 的测量结果之间的差异--俗称 "H0 张力"--仍然令科学界感到困惑。为了解决这一矛盾，有人提出了早期暗能量（EDE）模型，作为Λ-CDM 的替代方案，因为它们可以改变观测到的声平线和在此基础上测量推断出的哈勃常数。在本文中，我们研究了使用贝叶斯模型平均法（BMA）来评估作为 H0 张力解决方案的 EDE。贝叶斯模型平均法包括为模型指定一个先验值，并推导出一个后验值，就像贝叶斯分析中的任何其他未知参数一样。BMA 在计算上具有挑战性，因为我们必须近似计算模型和参数的联合后验。在这里，我们介绍一种利用现有 MCMC 软件并结合特定模型后验的 BMA 计算策略。通过对宇宙学数据集的综合分析，我们量化了 EDE 对 H0 差异的影响。我们发现，当我们把 Ia 型超新星的 H0 测量数据纳入分析时，EDE 模型的概率为 $sim 90%$ ，而其他数据则显示出对标准宇宙学模型的强烈偏好。最后，我们给出了对两种宇宙学模型共同参数边际化的约束。对于有 EDE 和无 EDE 模型的合理先验，H0 张力至少降低了 20%。
{"title":"A convenient approach to characterizing model uncertainty with application to early dark energy solutions of the Hubble tension","authors":"S Paradiso, M DiMarco, M Chen, G McGee, W J Percival","doi":"10.1093/mnras/stae101","DOIUrl":"https://doi.org/10.1093/mnras/stae101","url":null,"abstract":"Despite increasingly precise observations and sophisticated theoretical models, the discrepancy between measurements of H0 from the cosmic microwave background or from Baryon Acoustic Oscillations combined with Big-Bang Nucleosynthesis versus those from local distance ladder probes—commonly known as the ”H0 tension”—continues to perplex the scientific community. To address this tension, Early Dark Energy (EDE) models have been proposed as alternatives to Λ-CDM, as they can change the observed sound horizon and the inferred Hubble constant from measurements based on this. In this paper, we investigate the use of Bayesian Model Averaging (BMA) to evaluate EDE as a solution to the H0 tension. BMA consists of assigning a prior to the model and deriving a posterior as for any other unknown parameter in a Bayesian analysis. BMA can be computationally challenging in that one must approximate the joint posterior of both model and parameters. Here we present a computational strategy for BMA that exploits existing MCMC software and combines model-specific posteriors post-hoc. In application to a comprehensive analysis of cosmological datasets, we quantify the impact of EDE on the H0 discrepancy. We find an EDE model probability of $sim 90%$ whenever we include the H0 measurement from Type Ia Supernovae in the analysis, whereas the other data show a strong preference for the standard cosmological model. We finally present constraints on common parameters marginalized over both cosmological models. For reasonable priors on models with and without EDE, the H0 tension is reduced by at least 20%.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"140 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesca Gerardi, Andrei Cuceu, Benjamin Joachimi, Seshadri Nadathur, Andreu Font-Ribera
The Lyman-α (Lyα) three-dimensional correlation functions have been widely used to perform cosmological inference using the baryon acoustic oscillation (BAO) scale. While the traditional inference approach employs a data vector with several thousand data points, we apply near-maximal score compression down to tens of compressed data elements. We show that carefully constructed additional data beyond those linked to each inferred model parameter are required to preserve meaningful goodness-of-fit tests that guard against unknown systematics, and to avoid information loss due to non-linear parameter dependencies. We demonstrate, on suites of realistic mocks and DR16 data from the Extended Baryon Oscillation Spectroscopic Survey, that our compression approach is lossless and unbiased, yielding a posterior that is indistinguishable from that of the traditional analysis. As an early application, we investigate the impact of a covariance matrix estimated from a limited number of mocks, which is only well-conditioned in compressed space.
{"title":"Optimal data compression for Lyman-α forest cosmology","authors":"Francesca Gerardi, Andrei Cuceu, Benjamin Joachimi, Seshadri Nadathur, Andreu Font-Ribera","doi":"10.1093/mnras/stae092","DOIUrl":"https://doi.org/10.1093/mnras/stae092","url":null,"abstract":"The Lyman-α (Lyα) three-dimensional correlation functions have been widely used to perform cosmological inference using the baryon acoustic oscillation (BAO) scale. While the traditional inference approach employs a data vector with several thousand data points, we apply near-maximal score compression down to tens of compressed data elements. We show that carefully constructed additional data beyond those linked to each inferred model parameter are required to preserve meaningful goodness-of-fit tests that guard against unknown systematics, and to avoid information loss due to non-linear parameter dependencies. We demonstrate, on suites of realistic mocks and DR16 data from the Extended Baryon Oscillation Spectroscopic Survey, that our compression approach is lossless and unbiased, yielding a posterior that is indistinguishable from that of the traditional analysis. As an early application, we investigate the impact of a covariance matrix estimated from a limited number of mocks, which is only well-conditioned in compressed space.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"46 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139461120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rebecca Briffa, Celia Escamilla-Rivera, Jackson Levi Said, Jurgen Mifsud
Cosmology faces a pressing challenge with the Hubble constant (H0) tension, where the locally measured rate of the Universe’s expansion does not align with predictions from the cosmic microwave background (CMB) calibrated with ΛCDM model. Simultaneously, there is a growing tension involving the weighted amplitude of matter fluctuations, known as S8, 0 tension. Resolving both tensions within one framework would boost confidence in any one particular model. In this work, we analyse constraints in f(T) gravity, a framework that shows promise in shedding light on cosmic evolution. We thoroughly examine prominent f(T) gravity models using a combination of data sources, including Pantheon+ (SN), cosmic chronometers (CC), baryonic acoustic oscillations (BAO) and redshift space distortion (RSD) data. We use these models to derive a spectrum of H0 and S8, 0 values, aiming to gauge their ability to provide insights into, and potentially address, the challenges posed by the H0 and S8, 0 tensions.
{"title":"Growth of structures using redshift space distortion in f(T) Cosmology","authors":"Rebecca Briffa, Celia Escamilla-Rivera, Jackson Levi Said, Jurgen Mifsud","doi":"10.1093/mnras/stae103","DOIUrl":"https://doi.org/10.1093/mnras/stae103","url":null,"abstract":"Cosmology faces a pressing challenge with the Hubble constant (H0) tension, where the locally measured rate of the Universe’s expansion does not align with predictions from the cosmic microwave background (CMB) calibrated with ΛCDM model. Simultaneously, there is a growing tension involving the weighted amplitude of matter fluctuations, known as S8, 0 tension. Resolving both tensions within one framework would boost confidence in any one particular model. In this work, we analyse constraints in f(T) gravity, a framework that shows promise in shedding light on cosmic evolution. We thoroughly examine prominent f(T) gravity models using a combination of data sources, including Pantheon+ (SN), cosmic chronometers (CC), baryonic acoustic oscillations (BAO) and redshift space distortion (RSD) data. We use these models to derive a spectrum of H0 and S8, 0 values, aiming to gauge their ability to provide insights into, and potentially address, the challenges posed by the H0 and S8, 0 tensions.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"6 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Far-infrared observations from the Herschel Space Observatory are used to estimate the infrared (IR) properties of ultraviolet-selected galaxies. We stack the PACS (100, 160 μm) and SPIRE (250, 350 and 500μm) maps of the Chandra deep field south (CDFS) on a source list of galaxies selected in the rest-frame ultraviolet (UV) in a redshift range of 0.6 − 1.2. This source list is created using observations from the XMM-OM telescope survey in the CDFS using the UVW1 (2910 Å) filter. The stacked data are binned according to the UV luminosity function of these sources, and the average photometry of the UV-selected galaxies is estimated. By fitting modified black bodies and IR model templates to the stacked photometry, average dust temperatures and total IR luminosity are determined. The luminosity-weighted average temperatures are consistent with a weak trend of increasing temperature with redshift found by previous studies. Infrared excess, unobscured, and obscured star formation rate (SFR) values are obtained from the UV and IR luminosities. We see a trend in which dust attenuation increases as UV luminosity decreases. It remains constant as a function of IR luminosities at fixed redshift across the luminosity range of our sources. In comparison to local luminous infrared galaxies with similar SFRs, the higher redshift star-forming galaxies in the sample show a lesser degree of dust attenuation. Finally, the inferred dust attenuation is used to correct the unobscured SFR density in the redshift range 0.6-1.2. The dust-corrected SFR density is consistent with measurements from IR-selected samples at similar redshifts.
{"title":"On the Dust properties of the UV galaxies in the redshift range z ∼ 0.6 − 1.2","authors":"M Sharma, M J Page, M Symeonidis, I Ferreras","doi":"10.1093/mnras/stae135","DOIUrl":"https://doi.org/10.1093/mnras/stae135","url":null,"abstract":"Far-infrared observations from the Herschel Space Observatory are used to estimate the infrared (IR) properties of ultraviolet-selected galaxies. We stack the PACS (100, 160 μm) and SPIRE (250, 350 and 500μm) maps of the Chandra deep field south (CDFS) on a source list of galaxies selected in the rest-frame ultraviolet (UV) in a redshift range of 0.6 − 1.2. This source list is created using observations from the XMM-OM telescope survey in the CDFS using the UVW1 (2910 Å) filter. The stacked data are binned according to the UV luminosity function of these sources, and the average photometry of the UV-selected galaxies is estimated. By fitting modified black bodies and IR model templates to the stacked photometry, average dust temperatures and total IR luminosity are determined. The luminosity-weighted average temperatures are consistent with a weak trend of increasing temperature with redshift found by previous studies. Infrared excess, unobscured, and obscured star formation rate (SFR) values are obtained from the UV and IR luminosities. We see a trend in which dust attenuation increases as UV luminosity decreases. It remains constant as a function of IR luminosities at fixed redshift across the luminosity range of our sources. In comparison to local luminous infrared galaxies with similar SFRs, the higher redshift star-forming galaxies in the sample show a lesser degree of dust attenuation. Finally, the inferred dust attenuation is used to correct the unobscured SFR density in the redshift range 0.6-1.2. The dust-corrected SFR density is consistent with measurements from IR-selected samples at similar redshifts.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"48 4 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a study of C i/H2 relative abundance in the diffuse cold neutral medium (CNM). Using the chemical and thermal balance model, we calculate the dependence of C i/H2 on the main parameters of the medium: hydrogen number density, metallicity, strength of the UV field, and cosmic ray ionization rate (CRIR). We show that the observed relative C i and H2 column densities in damped Lyman alpha systems (DLAs) at high redshifts can be reproduced within our model assuming the typically expected conditions in the diffuse CNM. Using additional observed information on metallicity, H i column density, and excitation of C i fine-structure levels, as well as temperature, we estimated for a wide range metallicities in the CNM at high redshifts that CRIRs are in the range from ∼10−16 to a $rm few times 10^{-15}, rm s^{-1}$, hydrogen number densities are in the range ∼10−103 cm−3, and the UV field is in the range from 10−2 to a $rm few times 10^2$ of the Mathis field. We argue that because the observed quantities used in this work are quite homogeneous and much less affected by radiative transfer effects (in comparison with, for example, the dissociation of HD and UV pumping of H2 rotational levels), our estimates are quite robust against the assumption of the exact geometrical model of the cloud and local sources of the UV field.
我们对弥散冷中性介质（CNM）中的 C i/H2 相对丰度进行了研究。利用化学和热平衡模型，我们计算了 C i/H2 与介质主要参数的关系：氢的数量密度、金属性、紫外场强度和宇宙射线电离率（CRIR）。我们的研究表明，假定弥散 CNM 中存在典型的预期条件，在我们的模型中可以再现高红移下阻尼莱曼阿尔法系统（DLAs）中观测到的相对 C i 和 H2 柱密度。利用关于金属性、H i柱密度、C i细结构水平的激发以及温度的额外观测信息，我们估计在高红移下CNM的宽金属性范围内，CRIRs的范围从10-16到10^{-15}的几倍、rm s^{-1}$，氢数密度在 ∼10-103 cm-3 的范围内，紫外场在马西斯场的 10-2 到 10^2$ 的几倍之间。我们认为，由于这项工作中使用的观测量是相当均匀的，受辐射传递效应的影响要小得多（例如，与 HD 的解离和 H2 旋转水平的紫外泵浦相比），我们的估计值在假设云的精确几何模型和紫外场的局部来源的情况下是相当稳健的。
{"title":"Neutral carbon in diffuse interstellar medium: abundance matching with H2 for damped Lyman alpha systems at high redshifts","authors":"S A Balashev, D N Kosenko","doi":"10.1093/mnras/stad3971","DOIUrl":"https://doi.org/10.1093/mnras/stad3971","url":null,"abstract":"We present a study of C i/H2 relative abundance in the diffuse cold neutral medium (CNM). Using the chemical and thermal balance model, we calculate the dependence of C i/H2 on the main parameters of the medium: hydrogen number density, metallicity, strength of the UV field, and cosmic ray ionization rate (CRIR). We show that the observed relative C i and H2 column densities in damped Lyman alpha systems (DLAs) at high redshifts can be reproduced within our model assuming the typically expected conditions in the diffuse CNM. Using additional observed information on metallicity, H i column density, and excitation of C i fine-structure levels, as well as temperature, we estimated for a wide range metallicities in the CNM at high redshifts that CRIRs are in the range from ∼10−16 to a $rm few times 10^{-15}, rm s^{-1}$, hydrogen number densities are in the range ∼10−103 cm−3, and the UV field is in the range from 10−2 to a $rm few times 10^2$ of the Mathis field. We argue that because the observed quantities used in this work are quite homogeneous and much less affected by radiative transfer effects (in comparison with, for example, the dissociation of HD and UV pumping of H2 rotational levels), our estimates are quite robust against the assumption of the exact geometrical model of the cloud and local sources of the UV field.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"4 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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