Black hole - neutron star (BHNS) mergers are a promising target of current gravitational-wave (GW) and electromagnetic (EM) searches, being the putative origin of ultra-relativistic jets, gamma-ray emission, and r-process nucleosynthesis. However, the possibility of any EM emission accompanying a GW detection crucially depends on the amount of baryonic mass left after the coalescence, i.e. whether the neutron star (NS) undergoes a `tidal disruption' or `plunges' into the black hole (BH) while remaining essentially intact. As the first of a series of two papers, we here report the most systematic investigation to date of quasi-equilibrium sequences of initial data across a range of stellar compactnesses $mathcal{C}$, mass ratios $q$, BH spins $chi_{_{rm BH}}$, and equations of state satisfying all present observational constraints. Using an improved version of the elliptic initial-data solver FUKA, we have computed more than $1000$ individual configurations and estimated the onset of mass-shedding or the crossing of the innermost stable circular orbit in terms of the corresponding characteristic orbital angular velocities $Omega_{_{rm MS}}$ and $Omega_{_{rm ISCO}}$ as a function of $mathcal{C}, q$, and $chi_{_{rm BH}}$. To the best of our knowledge, this is the first time that the dependence of these frequencies on the BH spin is investigated. In turn, by setting $Omega_{_{rm MS}} = Omega_{_{rm ISCO}}$ it is possible to determine the separatrix between the `tidal disruption' or `plunge' scenarios as a function of the fundamental parameters of these systems, namely, $q, mathcal{C}$, and $chi_{_{rm BH}}$. Finally, we present a novel analysis of quantities related to the tidal forces in the initial data and discuss their dependence on spin and separation.
{"title":"Black hole-neutron star binaries with high spins and large mass asymmetries: I. Properties of quasi-equilibrium sequences","authors":"Konrad Topolski, Samuel Tootle, Luciano Rezzolla","doi":"arxiv-2409.06767","DOIUrl":"https://doi.org/arxiv-2409.06767","url":null,"abstract":"Black hole - neutron star (BHNS) mergers are a promising target of current\u0000gravitational-wave (GW) and electromagnetic (EM) searches, being the putative\u0000origin of ultra-relativistic jets, gamma-ray emission, and r-process\u0000nucleosynthesis. However, the possibility of any EM emission accompanying a GW\u0000detection crucially depends on the amount of baryonic mass left after the\u0000coalescence, i.e. whether the neutron star (NS) undergoes a `tidal disruption'\u0000or `plunges' into the black hole (BH) while remaining essentially intact. As\u0000the first of a series of two papers, we here report the most systematic\u0000investigation to date of quasi-equilibrium sequences of initial data across a\u0000range of stellar compactnesses $mathcal{C}$, mass ratios $q$, BH spins\u0000$chi_{_{rm BH}}$, and equations of state satisfying all present observational\u0000constraints. Using an improved version of the elliptic initial-data solver\u0000FUKA, we have computed more than $1000$ individual configurations and estimated\u0000the onset of mass-shedding or the crossing of the innermost stable circular\u0000orbit in terms of the corresponding characteristic orbital angular velocities\u0000$Omega_{_{rm MS}}$ and $Omega_{_{rm ISCO}}$ as a function of $mathcal{C}, q$, and $chi_{_{rm BH}}$. To the\u0000best of our knowledge, this is the first time that the dependence of these\u0000frequencies on the BH spin is investigated. In turn, by setting $Omega_{_{rm\u0000MS}} = Omega_{_{rm ISCO}}$ it is possible to determine the separatrix between\u0000the `tidal disruption' or `plunge' scenarios as a function of the fundamental\u0000parameters of these systems, namely, $q, mathcal{C}$, and $chi_{_{rm BH}}$.\u0000Finally, we present a novel analysis of quantities related to the tidal forces\u0000in the initial data and discuss their dependence on spin and separation.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesca Badaracco, Biswajit Banerjee, Marica Branchesi, Andrea Chincarini
Third generation and future upgrades of current gravitational-wave detectors will present exquisite sensitivities which will allow to detect a plethora of gravitational wave signals. Hence, a new problem to be solved arises: the detection and parameter estimation of overlapped signals. The problem of separating and identifying two signals that overlap in time, space or frequency is something well known in other fields (e.g. medicine and telecommunication). Blind source separation techniques are all those methods that aim at separating two or more unknown signals. This article provides a methodological review of the most common blind source separation techniques and it analyses whether they can be successfully applied to overlapped gravitational wave signals or not, while comparing the limits and advantages of each method.
{"title":"Blind source separation in 3rd generation gravitational-wave detectors","authors":"Francesca Badaracco, Biswajit Banerjee, Marica Branchesi, Andrea Chincarini","doi":"arxiv-2409.06458","DOIUrl":"https://doi.org/arxiv-2409.06458","url":null,"abstract":"Third generation and future upgrades of current gravitational-wave detectors\u0000will present exquisite sensitivities which will allow to detect a plethora of\u0000gravitational wave signals. Hence, a new problem to be solved arises: the\u0000detection and parameter estimation of overlapped signals. The problem of\u0000separating and identifying two signals that overlap in time, space or frequency\u0000is something well known in other fields (e.g. medicine and telecommunication).\u0000Blind source separation techniques are all those methods that aim at separating\u0000two or more unknown signals. This article provides a methodological review of\u0000the most common blind source separation techniques and it analyses whether they\u0000can be successfully applied to overlapped gravitational wave signals or not,\u0000while comparing the limits and advantages of each method.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alistair McLeod, Damon Beveridge, Linqing Wen, Andreas Wicenec
Gravitational waves are now routinely detected from compact binary mergers, with binary neutron star mergers being of note for multi-messenger astronomy as they have been observed to produce electromagnetic counterparts. Novel search pipelines for these mergers could increase the combined search sensitivity, and could improve the ability to detect real gravitational wave signals in the presence of glitches and non-stationary detector noise. Deep learning has found success in other areas of gravitational wave data analysis, but a sensitive deep learning-based search for binary neutron star mergers has proven elusive due to their long signal length. In this work, we present a deep learning pipeline for detecting binary neutron star mergers. By training a convolutional neural network to detect binary neutron star mergers in the signal-to-noise ratio time series, we concentrate signal power into a shorter and more consistent timescale than strain-based methods, while also being able to train our network to be robust against glitches. We compare our pipeline's sensitivity to the three offline detection pipelines using injections in real gravitational wave data, and find that our pipeline has a comparable sensitivity to the current pipelines below the 1 per 2 months detection threshold. Furthermore, we find that our pipeline can increase the total number of binary neutron star detections by 12% at a false alarm rate of 1 per 2 months. The pipeline is also able to successfully detect the two binary neutron star mergers detected so far by the LIGO-Virgo-KAGRA collaboration, GW170817 and GW190425, despite the loud glitch present in GW170817.
{"title":"A Binary Neutron Star Merger Search Pipeline Powered by Deep Learning","authors":"Alistair McLeod, Damon Beveridge, Linqing Wen, Andreas Wicenec","doi":"arxiv-2409.06266","DOIUrl":"https://doi.org/arxiv-2409.06266","url":null,"abstract":"Gravitational waves are now routinely detected from compact binary mergers,\u0000with binary neutron star mergers being of note for multi-messenger astronomy as\u0000they have been observed to produce electromagnetic counterparts. Novel search\u0000pipelines for these mergers could increase the combined search sensitivity, and\u0000could improve the ability to detect real gravitational wave signals in the\u0000presence of glitches and non-stationary detector noise. Deep learning has found\u0000success in other areas of gravitational wave data analysis, but a sensitive\u0000deep learning-based search for binary neutron star mergers has proven elusive\u0000due to their long signal length. In this work, we present a deep learning\u0000pipeline for detecting binary neutron star mergers. By training a convolutional\u0000neural network to detect binary neutron star mergers in the signal-to-noise\u0000ratio time series, we concentrate signal power into a shorter and more\u0000consistent timescale than strain-based methods, while also being able to train\u0000our network to be robust against glitches. We compare our pipeline's\u0000sensitivity to the three offline detection pipelines using injections in real\u0000gravitational wave data, and find that our pipeline has a comparable\u0000sensitivity to the current pipelines below the 1 per 2 months detection\u0000threshold. Furthermore, we find that our pipeline can increase the total number\u0000of binary neutron star detections by 12% at a false alarm rate of 1 per 2\u0000months. The pipeline is also able to successfully detect the two binary neutron\u0000star mergers detected so far by the LIGO-Virgo-KAGRA collaboration, GW170817\u0000and GW190425, despite the loud glitch present in GW170817.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sankarshana Srinivasan, Daniel B Thomas, Peter L. Taylor
Stage IV large scale structure surveys are promising probes of gravity on cosmological scales. Due to the vast model-space in the modified gravity literature, model-independent parameterisations represent useful and scalable ways to test extensions of $Lambda$CDM. In this work we use a recently validated approach of computing the non-linear $3times 2$pt observables in modified gravity models with a time-varying effective gravitational constant $mu$ and a gravitational slip $eta$ that is binned in redshift to produce Fisher forecasts for an LSST Y10-like survey. We also include in our modelling an effective nulling scheme for weak-lensing by applying the BNT transformation that localises the weak-lensing kernel enabling well-informed scale cuts. We show that the combination of improved non-linear modelling and better control of the scales that are modelled/cut yields high precision constraints on the cosmological and modified gravity parameters. We find that 4 redshift bins for $mu$ of width corresponding to equal incremental $Lambda$CDM growth is optimal given the state-of-the-art modelling and show how the BNT transformation can be used to mitigate the impact of small-scale systematic effects, such as baryonic feedback.
{"title":"Cosmological gravity on all scales IV: 3x2pt Fisher forecasts for pixelised phenomenological modified gravity","authors":"Sankarshana Srinivasan, Daniel B Thomas, Peter L. Taylor","doi":"arxiv-2409.06569","DOIUrl":"https://doi.org/arxiv-2409.06569","url":null,"abstract":"Stage IV large scale structure surveys are promising probes of gravity on\u0000cosmological scales. Due to the vast model-space in the modified gravity\u0000literature, model-independent parameterisations represent useful and scalable\u0000ways to test extensions of $Lambda$CDM. In this work we use a recently\u0000validated approach of computing the non-linear $3times 2$pt observables in\u0000modified gravity models with a time-varying effective gravitational constant\u0000$mu$ and a gravitational slip $eta$ that is binned in redshift to produce\u0000Fisher forecasts for an LSST Y10-like survey. We also include in our modelling\u0000an effective nulling scheme for weak-lensing by applying the BNT transformation\u0000that localises the weak-lensing kernel enabling well-informed scale cuts. We\u0000show that the combination of improved non-linear modelling and better control\u0000of the scales that are modelled/cut yields high precision constraints on the\u0000cosmological and modified gravity parameters. We find that 4 redshift bins for\u0000$mu$ of width corresponding to equal incremental $Lambda$CDM growth is\u0000optimal given the state-of-the-art modelling and show how the BNT\u0000transformation can be used to mitigate the impact of small-scale systematic\u0000effects, such as baryonic feedback.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past decade and a half, adoption of Bayesian inference in pulsar timing analysis has led to increasingly sophisticated models. The recent announcement of evidence for a stochastic background of gravitational waves by various pulsar timing array projects highlighted Bayesian inference as a central tool for parameter estimation and model selection. Despite its success, Bayesian inference is occasionally misused in the pulsar timing community. A common workflow is that the data is analyzed in multiple steps: a first analysis of single pulsars individually, and a subsequent analysis of the whole array of pulsars. A mistake that is then sometimes introduced stems from using the posterior distribution to craft the prior for the analysis of the same data in a second step, a practice referred to in the statistics literature as ``circular analysis.'' This is done to prune the model for computational efficiency. Multiple recent high-profile searches for gravitational waves by pulsar timing array (PTA) projects have this workflow. This letter highlights this error and suggests that Spike and Slab priors can be used to carry out model averaging instead of model selection in a single pass. Spike and Slab priors are proved to be equal to Log-Uniform priors.
{"title":"Use Model Averaging instead of Model Selection in Pulsar Timing","authors":"Rutger van Haasteren","doi":"arxiv-2409.06050","DOIUrl":"https://doi.org/arxiv-2409.06050","url":null,"abstract":"Over the past decade and a half, adoption of Bayesian inference in pulsar\u0000timing analysis has led to increasingly sophisticated models. The recent\u0000announcement of evidence for a stochastic background of gravitational waves by\u0000various pulsar timing array projects highlighted Bayesian inference as a\u0000central tool for parameter estimation and model selection. Despite its success,\u0000Bayesian inference is occasionally misused in the pulsar timing community. A\u0000common workflow is that the data is analyzed in multiple steps: a first\u0000analysis of single pulsars individually, and a subsequent analysis of the whole\u0000array of pulsars. A mistake that is then sometimes introduced stems from using\u0000the posterior distribution to craft the prior for the analysis of the same data\u0000in a second step, a practice referred to in the statistics literature as\u0000``circular analysis.'' This is done to prune the model for computational\u0000efficiency. Multiple recent high-profile searches for gravitational waves by\u0000pulsar timing array (PTA) projects have this workflow. This letter highlights\u0000this error and suggests that Spike and Slab priors can be used to carry out\u0000model averaging instead of model selection in a single pass. Spike and Slab\u0000priors are proved to be equal to Log-Uniform priors.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jaiane Santos, Carlos Bengaly, Jonathan Morais, Rodrigo S. Gonçalves
We measure the speed of light with current observations, such as Type Ia Supernova, galaxy ages, radial BAO mode, as well as simulations of future redshift surveys and gravitational waves as standard sirens. By means of a Gaussian Process reconstruction, we find that the precision of such measurements can be improved from roughly 6% to 1.5-2%, in light of these forthcoming observations. This result demonstrates that we will be able to perform a cosmological measurement of a fundamental physical constant with unprecedented precision, which will help us underpinning if its value is truly consistent with local measurements, as predicted by the standard model of Cosmology.
我们用当前的观测数据来测量光速，比如Ia型超新星、星系年龄、径向BAO模式，以及作为标准警报器的未来移测量和引力波的模拟。通过高斯过程重建（Gaussian Process reconstruction），我们发现根据这些即将到来的观测，这种测量的精度可以从大约6%提高到1.5-2%。这一结果表明，我们将能够以前所未有的精度对一个基本物理常数进行宇宙学测量，这将有助于我们确定它的值是否真的与宇宙学标准模型所预言的本地测量值一致。
{"title":"Measuring the speed of light with cosmological observations: current constraints and forecasts","authors":"Jaiane Santos, Carlos Bengaly, Jonathan Morais, Rodrigo S. Gonçalves","doi":"arxiv-2409.05838","DOIUrl":"https://doi.org/arxiv-2409.05838","url":null,"abstract":"We measure the speed of light with current observations, such as Type Ia\u0000Supernova, galaxy ages, radial BAO mode, as well as simulations of future\u0000redshift surveys and gravitational waves as standard sirens. By means of a\u0000Gaussian Process reconstruction, we find that the precision of such\u0000measurements can be improved from roughly 6% to 1.5-2%, in light of these\u0000forthcoming observations. This result demonstrates that we will be able to\u0000perform a cosmological measurement of a fundamental physical constant with\u0000unprecedented precision, which will help us underpinning if its value is truly\u0000consistent with local measurements, as predicted by the standard model of\u0000Cosmology.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Oliveira dos Santos, H. F. Santana Mota, E. R. Bezerra de Mello
In this paper, we investigate the vacuum bosonic current density induced by a carrying-magnetic-flux cosmic string in a $(D+1)$-de Sitter spacetime considering the presence of two flat boundaries perpendicular to it. In this setup, the Robin boundary conditions are imposed on the scalar charged quantum field on the boundaries. The particular cases of Dirichlet and Neumann boundary conditions are studied separately. Due to the coupling of the quantum scalar field with the classical gauge field, corresponding to a magnetic flux running along the string's core, a nonzero vacuum expectation value for the current density operator along the azimuthal direction is induced. The two boundaries divide the space in three regions with different properties of the vacuum states. In this way, our main objective is to calculate the induced currents in these three regions. In order to develop this analysis we calculate, for both regions, the positive frequency Wightman functions. Because the vacuum bosonic current in dS space has been investigated before, in this paper we consider only the contributions induced by the boundaries. We show that for each region the azimuthal current densities are odd functions of the magnetic flux along the string. To probe the correctness of our results, we take the particular cases and analyze some asymptotic limits of the parameters of the model. Also some graphs are presented exhibiting the behavior of the current with relevant physical parameter of the system.
{"title":"Current density induced by a cosmic string in de Sitter spacetime in the presence of two flat boundaries","authors":"W. Oliveira dos Santos, H. F. Santana Mota, E. R. Bezerra de Mello","doi":"arxiv-2409.05691","DOIUrl":"https://doi.org/arxiv-2409.05691","url":null,"abstract":"In this paper, we investigate the vacuum bosonic current density induced by a\u0000carrying-magnetic-flux cosmic string in a $(D+1)$-de Sitter spacetime\u0000considering the presence of two flat boundaries perpendicular to it. In this\u0000setup, the Robin boundary conditions are imposed on the scalar charged quantum\u0000field on the boundaries. The particular cases of Dirichlet and Neumann boundary\u0000conditions are studied separately. Due to the coupling of the quantum scalar\u0000field with the classical gauge field, corresponding to a magnetic flux running\u0000along the string's core, a nonzero vacuum expectation value for the current\u0000density operator along the azimuthal direction is induced. The two boundaries\u0000divide the space in three regions with different properties of the vacuum\u0000states. In this way, our main objective is to calculate the induced currents in\u0000these three regions. In order to develop this analysis we calculate, for both\u0000regions, the positive frequency Wightman functions. Because the vacuum bosonic\u0000current in dS space has been investigated before, in this paper we consider\u0000only the contributions induced by the boundaries. We show that for each region\u0000the azimuthal current densities are odd functions of the magnetic flux along\u0000the string. To probe the correctness of our results, we take the particular\u0000cases and analyze some asymptotic limits of the parameters of the model. Also\u0000some graphs are presented exhibiting the behavior of the current with relevant\u0000physical parameter of the system.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we investigate the properties of relativistic stars made of isotropic matter within the framework of the minimal Standard Model Extension, where a bumblebee field coupled to spacetime induces spontaneous Lorentz symmetry breaking. We adopt analytic equations-of-state describing either condensate dark stars or strange quark stars. We solve the structure equations numerically, and we compute the mass-to-radius relationships. The influence of the bumblebee parameter $l$ is examined in detail, and an upper bound is obtained using the massive pulsar PSR J0740+6620 and the strangely light HESS J1731-347 compact object.
{"title":"Strange Quark Stars and Condensate Dark Stars in Bumblebee Gravity","authors":"Grigoris Panotopoulos, Ali Övgün","doi":"arxiv-2409.05801","DOIUrl":"https://doi.org/arxiv-2409.05801","url":null,"abstract":"In this paper, we investigate the properties of relativistic stars made of\u0000isotropic matter within the framework of the minimal Standard Model Extension,\u0000where a bumblebee field coupled to spacetime induces spontaneous Lorentz\u0000symmetry breaking. We adopt analytic equations-of-state describing either\u0000condensate dark stars or strange quark stars. We solve the structure equations\u0000numerically, and we compute the mass-to-radius relationships. The influence of\u0000the bumblebee parameter $l$ is examined in detail, and an upper bound is\u0000obtained using the massive pulsar PSR J0740+6620 and the strangely light HESS\u0000J1731-347 compact object.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We analyze gravitational lensing and their cast images from thin-disks in shadow observations of a family of spherically symmetric black hole solutions previously derived within the framework of Loop Quantum Gravity. Such black holes depend on two parameters (besides the mass of the black hole itself), $P$ and $a_0$, the latter imbuing the configurations with an interior wormhole structure. Using the bounds from the Event Horizon Telescope regarding the shadow's radius of Sgr A$^*$ that constrain the parameter $P lesssim 0.08(2sigma)$ (at $a_0=0$), we study the modifications to weak and strong gravitational lensing induced by these geometries as compared to the Schwarzschild black hole within this range. In particular, we discuss several observables in the strong field regime related to the luminosity decay, the angular separation, and the flux ratio between multiples images of the source. Furthermore, we consider the cast images of these black holes when illuminated by a geometrically and optically thin accretion disk according to several semi-analytic profiles for the disk's emission.
{"title":"Gravitational lensing and shadows from thin-disks in Loop Quantum Gravity self-dual black holes","authors":"David J. Patiño Pomares, Diego Rubiera-Garcia","doi":"arxiv-2409.05371","DOIUrl":"https://doi.org/arxiv-2409.05371","url":null,"abstract":"We analyze gravitational lensing and their cast images from thin-disks in\u0000shadow observations of a family of spherically symmetric black hole solutions\u0000previously derived within the framework of Loop Quantum Gravity. Such black\u0000holes depend on two parameters (besides the mass of the black hole itself), $P$\u0000and $a_0$, the latter imbuing the configurations with an interior wormhole\u0000structure. Using the bounds from the Event Horizon Telescope regarding the\u0000shadow's radius of Sgr A$^*$ that constrain the parameter $P lesssim\u00000.08(2sigma)$ (at $a_0=0$), we study the modifications to weak and strong\u0000gravitational lensing induced by these geometries as compared to the\u0000Schwarzschild black hole within this range. In particular, we discuss several\u0000observables in the strong field regime related to the luminosity decay, the\u0000angular separation, and the flux ratio between multiples images of the source.\u0000Furthermore, we consider the cast images of these black holes when illuminated\u0000by a geometrically and optically thin accretion disk according to several\u0000semi-analytic profiles for the disk's emission.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates polarized images of an equatorial synchrotron-emitting ring surrounding hairy black holes within the Einstein-Maxwell-scalar theory. Our analysis demonstrates qualitative similarities between the polarization patterns of hairy black holes and Schwarzschild black holes. However, due to the non-minimal coupling between the scalar and electromagnetic fields, an increase in black hole charge and coupling constant can substantially amplify polarization intensity and induce deviations in the electric vector position angle. These effects may offer observational signatures to distinguish hairy black holes from Schwarzschild black holes.
{"title":"Polarized Image of a Synchrotron-emitting Ring in Einstein-Maxwell-scalar Theory","authors":"Yiqian Chen, Lang Cheng, Peng Wang, Haitang Yang","doi":"arxiv-2409.05304","DOIUrl":"https://doi.org/arxiv-2409.05304","url":null,"abstract":"This study investigates polarized images of an equatorial\u0000synchrotron-emitting ring surrounding hairy black holes within the\u0000Einstein-Maxwell-scalar theory. Our analysis demonstrates qualitative\u0000similarities between the polarization patterns of hairy black holes and\u0000Schwarzschild black holes. However, due to the non-minimal coupling between the\u0000scalar and electromagnetic fields, an increase in black hole charge and\u0000coupling constant can substantially amplify polarization intensity and induce\u0000deviations in the electric vector position angle. These effects may offer\u0000observational signatures to distinguish hairy black holes from Schwarzschild\u0000black holes.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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