Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/093
Shulei Cao and Bharat Ratra
By using gamma-ray burst (GRB) data to simultaneously constrain Amati correlation parameters and cosmological parameters in six spatially flat and nonflat dark energy cosmological models, we show that an updated 220 GRB version of the Jia et al. [1] GRB data compilation are standardizable through the Amati correlation and so can be used for cosmological analyses. However, the resulting GRB data constraints on the current value of the nonrelativistic matter density parameter, Ωm0, are in > 2σ tension with those from a joint analysis of better-established Hubble parameter [H(z)] and baryon acoustic oscillation (BAO) data for most of the cosmological models we consider, indicating that these GRB data cannot be jointly used with better-established H(z) + BAO data to constrain cosmological parameters.
通过使用伽马射线暴（GRB）数据同时约束六个空间平坦和非平坦暗能量宇宙学模型中的阿马蒂相关参数和宇宙学参数，我们表明贾等人[1]GRB数据汇编的220个GRB更新版本通过阿马蒂相关是可标准化的，因此可用于宇宙学分析。然而，对于我们考虑的大多数宇宙学模型来说，GRB 数据对非相对论物质密度参数 Ωm0 的当前值的约束，与对更完善的哈勃参数[H(z)]和重子声振荡（BAO）数据的联合分析结果的约束，存在 > 2σ 的张力，这表明这些 GRB 数据不能与更完善的 H(z) + BAO 数据联合用于约束宇宙学参数。
{"title":"Testing the standardizability of, and deriving cosmological constraints from, a new Amati-correlated gamma-ray burst data compilation","authors":"Shulei Cao and Bharat Ratra","doi":"10.1088/1475-7516/2024/10/093","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/093","url":null,"abstract":"By using gamma-ray burst (GRB) data to simultaneously constrain Amati correlation parameters and cosmological parameters in six spatially flat and nonflat dark energy cosmological models, we show that an updated 220 GRB version of the Jia et al. [1] GRB data compilation are standardizable through the Amati correlation and so can be used for cosmological analyses. However, the resulting GRB data constraints on the current value of the nonrelativistic matter density parameter, Ωm0, are in > 2σ tension with those from a joint analysis of better-established Hubble parameter [H(z)] and baryon acoustic oscillation (BAO) data for most of the cosmological models we consider, indicating that these GRB data cannot be jointly used with better-established H(z) + BAO data to constrain cosmological parameters.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"5 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/083
Chen Yang, Sai Wang, Meng-Lin Zhao and Xin Zhang
Primordial black holes (PBHs), more generally, BHs, undergo evaporation and, in principle, will end their lives in bursts of very high-energy gamma rays. The notable aspect of the PBHs with an initial mass of ∼ 1014 g is that they are expected to end their lives today. In this work, we assess the potential sensitivity of the Large High Altitude Air Shower Observatory (LHAASO) in detecting the local burst rate density of PBHs. Our results suggest that LHAASO is capable of probing for PBH bursts within a proximity of ∼ 0.1 pc from the Sun, measuring a local burst rate density of ∼ 1200 (or 700)pc-3 yr-1 with 99% confidence during a 3-year (or 5-year) observational campaign. This level of sensitivity surpasses the most rigorous observational constraint provided by the High Altitude Water Cherenkov Observatory (HAWC) by an order of magnitude. Additionally, we propose data analysis strategies for LHAASO to optimize the search for PBHs and reach its potential detection limits.
{"title":"Search for the Hawking radiation of primordial black holes: prospective sensitivity of LHAASO","authors":"Chen Yang, Sai Wang, Meng-Lin Zhao and Xin Zhang","doi":"10.1088/1475-7516/2024/10/083","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/083","url":null,"abstract":"Primordial black holes (PBHs), more generally, BHs, undergo evaporation and, in principle, will end their lives in bursts of very high-energy gamma rays. The notable aspect of the PBHs with an initial mass of ∼ 1014 g is that they are expected to end their lives today. In this work, we assess the potential sensitivity of the Large High Altitude Air Shower Observatory (LHAASO) in detecting the local burst rate density of PBHs. Our results suggest that LHAASO is capable of probing for PBH bursts within a proximity of ∼ 0.1 pc from the Sun, measuring a local burst rate density of ∼ 1200 (or 700)pc-3 yr-1 with 99% confidence during a 3-year (or 5-year) observational campaign. This level of sensitivity surpasses the most rigorous observational constraint provided by the High Altitude Water Cherenkov Observatory (HAWC) by an order of magnitude. Additionally, we propose data analysis strategies for LHAASO to optimize the search for PBHs and reach its potential detection limits.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"5 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/089
Sergi Novell-Masot, Héctor Gil-Marín, Licia Verde, J. Aguilar, S. Ahlen, S. Brieden, D. Brooks, T. Claybaugh, A. de la Macorra, J.E. Forero-Romero, E. Gaztañaga, S.Gontcho A. Gontcho, G. Gutierrez, K. Honscheid, C. Howlett, R. Kehoe, T. Kisner, A. Lambert, M.E. Levi, M. Manera, A. Meisner, R. Miquel, G. Niz, F. Prada, G. Rossi, E. Sanchez, M. Schubnell, H. Seo, D. Sprayberry, G. Tarlé and B.A. Weaver
We evaluate the performance of the catalog-level blind analysis technique (blinding) presented in Brieden et al. (2020) in the context of a fixed template power spectrum and bispectrum analysis. This blinding scheme, which is tailored for galaxy redshift surveys similar to the Dark Energy Spectroscopic Instrument (DESI), has two components: the so-called “AP blinding” (concerning the dilation parameters α∥, α⊥) and “RSD blinding” (redshift space distortions, affecting the growth rate parameter f). Through extensive testing, including checks for the RSD part in cubic boxes, the impact of AP blinding on mocks with realistic survey sky coverage, and the implementation of a full AP+RSD blinding pipeline, our analysis demonstrates the effectiveness of the technique in preserving the integrity of cosmological parameter estimation when the analysis includes the bispectrum statistic. We emphasize the critical role of sophisticated — and difficult to accidentally unblind — blinding methods in precision cosmology.
{"title":"Catalog-level blinding on the bispectrum for DESI-like galaxy surveys","authors":"Sergi Novell-Masot, Héctor Gil-Marín, Licia Verde, J. Aguilar, S. Ahlen, S. Brieden, D. Brooks, T. Claybaugh, A. de la Macorra, J.E. Forero-Romero, E. Gaztañaga, S.Gontcho A. Gontcho, G. Gutierrez, K. Honscheid, C. Howlett, R. Kehoe, T. Kisner, A. Lambert, M.E. Levi, M. Manera, A. Meisner, R. Miquel, G. Niz, F. Prada, G. Rossi, E. Sanchez, M. Schubnell, H. Seo, D. Sprayberry, G. Tarlé and B.A. Weaver","doi":"10.1088/1475-7516/2024/10/089","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/089","url":null,"abstract":"We evaluate the performance of the catalog-level blind analysis technique (blinding) presented in Brieden et al. (2020) in the context of a fixed template power spectrum and bispectrum analysis. This blinding scheme, which is tailored for galaxy redshift surveys similar to the Dark Energy Spectroscopic Instrument (DESI), has two components: the so-called “AP blinding” (concerning the dilation parameters α∥, α⊥) and “RSD blinding” (redshift space distortions, affecting the growth rate parameter f). Through extensive testing, including checks for the RSD part in cubic boxes, the impact of AP blinding on mocks with realistic survey sky coverage, and the implementation of a full AP+RSD blinding pipeline, our analysis demonstrates the effectiveness of the technique in preserving the integrity of cosmological parameter estimation when the analysis includes the bispectrum statistic. We emphasize the critical role of sophisticated — and difficult to accidentally unblind — blinding methods in precision cosmology.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"60 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/090
Lorenzo Boldorini and Giovanni Montani
We study how the presence of an area gap, different than zero, affects the gravitational collapse of a dust ball. The implementation of such discreteness is achieved through the framework of polymer quantization, a scheme inspired by loop quantum gravity (LQG). We study the collapse using variables which represent the area, in order to impose the non-zero area gap condition. The collapse is analyzed for both the flat and spherical Oppenheimer-Snyder models. In both scenarios the formation of the singularity is avoided, due to the inversion of the velocity at finite values of the sphere surface. This happens due to the presence of a negative pressure, with origins at a quantum level. When the inversion happens inside the black hole event horizon, we achieve a geometry transition to a white hole. When the inversion happens outside the event horizon, we find a new possible astrophysical object. A characterization of such hypothetical object is done. Some constraints on the value for the area gap are also imposed in order to maintain the link with our already established physical theories.
{"title":"Effective quantum gravitational collapse in a polymer framework","authors":"Lorenzo Boldorini and Giovanni Montani","doi":"10.1088/1475-7516/2024/10/090","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/090","url":null,"abstract":"We study how the presence of an area gap, different than zero, affects the gravitational collapse of a dust ball. The implementation of such discreteness is achieved through the framework of polymer quantization, a scheme inspired by loop quantum gravity (LQG). We study the collapse using variables which represent the area, in order to impose the non-zero area gap condition. The collapse is analyzed for both the flat and spherical Oppenheimer-Snyder models. In both scenarios the formation of the singularity is avoided, due to the inversion of the velocity at finite values of the sphere surface. This happens due to the presence of a negative pressure, with origins at a quantum level. When the inversion happens inside the black hole event horizon, we achieve a geometry transition to a white hole. When the inversion happens outside the event horizon, we find a new possible astrophysical object. A characterization of such hypothetical object is done. Some constraints on the value for the area gap are also imposed in order to maintain the link with our already established physical theories.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"26 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/082
Mohammed Shafi, Edmund J. Copeland, Rafid Mahbub, Swagat S. Mishra and Soumen Basak
We investigate the formation and decay of oscillons during the post-inflationary reheating epoch from inflaton oscillations around asymptotically flat potentials V(φ) in the presence of an external coupling of the form 1/2 g2φ2χ2. It is well-known that in the absence of such an external coupling, the attractive self-interaction term in the potential leads to the formation of copious amounts of long-lived oscillons both for symmetric and asymmetric plateau potentials. We perform a detailed numerical analysis to study the formation of oscillons in the α-attractor E- and T-model potentials using the publicly available lattice simulation code CosmoLattice. We observe the formation of nonlinear oscillon-like structures with the average equation of state ⟨wφ⟩ ≃ 0 for a range of values of the inflaton self-coupling λ and the external coupling g2. Our results demonstrate that oscillons form even in the presence of an external coupling and we determine the upper bound on g2 which facilitates oscillon formation. We also find that eventually, these oscillons decay into the scalar inflaton radiation as well as into the quanta of the offspring field χ. Thus, we establish the possibility that reheating could have proceeded through the channel of oscillon decay, along with the usual decay of the oscillating inflaton condensate into χ particles. For a given value of the self-coupling λ, we notice that the lifetime of a population of oscillons decreases with an increase in the strength of the external coupling, following an (approximately) inverse power-law dependence on g2.
{"title":"Formation and decay of oscillons after inflation in the presence of an external coupling. Part I. Lattice simulations","authors":"Mohammed Shafi, Edmund J. Copeland, Rafid Mahbub, Swagat S. Mishra and Soumen Basak","doi":"10.1088/1475-7516/2024/10/082","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/082","url":null,"abstract":"We investigate the formation and decay of oscillons during the post-inflationary reheating epoch from inflaton oscillations around asymptotically flat potentials V(φ) in the presence of an external coupling of the form 1/2 g2φ2χ2. It is well-known that in the absence of such an external coupling, the attractive self-interaction term in the potential leads to the formation of copious amounts of long-lived oscillons both for symmetric and asymmetric plateau potentials. We perform a detailed numerical analysis to study the formation of oscillons in the α-attractor E- and T-model potentials using the publicly available lattice simulation code CosmoLattice. We observe the formation of nonlinear oscillon-like structures with the average equation of state ⟨wφ⟩ ≃ 0 for a range of values of the inflaton self-coupling λ and the external coupling g2. Our results demonstrate that oscillons form even in the presence of an external coupling and we determine the upper bound on g2 which facilitates oscillon formation. We also find that eventually, these oscillons decay into the scalar inflaton radiation as well as into the quanta of the offspring field χ. Thus, we establish the possibility that reheating could have proceeded through the channel of oscillon decay, along with the usual decay of the oscillating inflaton condensate into χ particles. For a given value of the self-coupling λ, we notice that the lifetime of a population of oscillons decreases with an increase in the strength of the external coupling, following an (approximately) inverse power-law dependence on g2.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"236 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/085
Francesco Iacovelli, Enis Belgacem, Michele Maggiore, Michele Mancarella and Niccolò Muttoni
Recently, detailed studies have been made to compare the performance of the European next generation GW observatory Einstein Telescope (ET) in a single-site triangular configuration with the performance of a configuration featuring two L-shaped detectors in different sites, still taken to have all other ET characteristics except for the geometry, in particular, underground and composed of a low-frequency interferometer working at cryogenic temperatures and a high-frequency interferometer working at room temperature. Here we study a further possibility for a European network, made by a single L-shaped underground detector, like one of the detectors considered for the 2L version of ET, and a single third-generation 20-km L-shaped interferometer on the surface. We compare the performances of such a network to those of the triangle and of the 2L-underground ET configurations. We then examine the performance of an intercontinental network made by a 40-km CE in the U.S., together with any of these European networks.
最近，我们进行了详细的研究，比较了欧洲下一代全球暖化观测站爱因斯坦望远镜（ET）在单站点三角形配置中的性能，以及在不同站点安装两个 L 形探测器的配置的性能，该配置除几何形状外仍具有 ET 的所有其他特征，特别是在地下，由一个在低温下工作的低频干涉仪和一个在室温下工作的高频干涉仪组成。在此，我们研究了欧洲网络的另一种可能性，即由一个 L 型地下探测器（类似于为 2L 版 ET 所考虑的探测器之一）和一个 20 千米长的第三代 L 型地表干涉仪组成。我们将这种网络的性能与三角形和 2L 型地下 ET 配置的性能进行了比较。然后，我们考察了由美国 40 千米长的 CE 构成的洲际网络以及上述任何欧洲网络的性能。
{"title":"Combining underground and on-surface third-generation gravitational-wave interferometers","authors":"Francesco Iacovelli, Enis Belgacem, Michele Maggiore, Michele Mancarella and Niccolò Muttoni","doi":"10.1088/1475-7516/2024/10/085","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/085","url":null,"abstract":"Recently, detailed studies have been made to compare the performance of the European next generation GW observatory Einstein Telescope (ET) in a single-site triangular configuration with the performance of a configuration featuring two L-shaped detectors in different sites, still taken to have all other ET characteristics except for the geometry, in particular, underground and composed of a low-frequency interferometer working at cryogenic temperatures and a high-frequency interferometer working at room temperature. Here we study a further possibility for a European network, made by a single L-shaped underground detector, like one of the detectors considered for the 2L version of ET, and a single third-generation 20-km L-shaped interferometer on the surface. We compare the performances of such a network to those of the triangle and of the 2L-underground ET configurations. We then examine the performance of an intercontinental network made by a 40-km CE in the U.S., together with any of these European networks.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"34 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/086
A. Nozdrina and D. Besson
Over the last three decades, several experimental initiatives have been launched with the goal of observing radio-frequency signals produced by ultra-high energy neutrinos (UHEN) interacting in solid media. Observed neutrino event signatures comprise impulsive signals with duration of order the inverse of the antenna+system bandwidth (∼10 ns), superimposed upon an incoherent (typically white noise) thermal noise spectrum. Whereas bulk volume scattering (VS) of radio-frequency (RF) signals is well-studied within the radio-glaciological communities, polar ice-based neutrino-detection experiments have thus far neglected VS in their signal projections. As discussed herein, coherent volume scattering (CVS, for which the phase of the incident signal is preserved during scattering) generated by in-ice neutrino interactions may similarly produce short-duration signal-like power, albeit with a slightly extended time structure, and thereby enhance neutrino detection rates, whereas incoherent (randomized phase) volume scattering (IVS) will persist for O(100 ns), appearing similar to thermal white noise and therefore reducing the measured Signal-to-Noise Ratio (SNR) of neutrino signals. Herein, we present the expected voltage profiles resulting from in-ice volume scattering as a function of the molecular scattering cross-section, for both CVS and IVS, and assess their impact on UHEN experiments. VS contributions are currently only weakly constrained by extant data; stronger limits may be obtained with dedicated calibration experiments.
{"title":"Implications of in-ice volume scattering for radio-frequency neutrino experiments","authors":"A. Nozdrina and D. Besson","doi":"10.1088/1475-7516/2024/10/086","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/086","url":null,"abstract":"Over the last three decades, several experimental initiatives have been launched with the goal of observing radio-frequency signals produced by ultra-high energy neutrinos (UHEN) interacting in solid media. Observed neutrino event signatures comprise impulsive signals with duration of order the inverse of the antenna+system bandwidth (∼10 ns), superimposed upon an incoherent (typically white noise) thermal noise spectrum. Whereas bulk volume scattering (VS) of radio-frequency (RF) signals is well-studied within the radio-glaciological communities, polar ice-based neutrino-detection experiments have thus far neglected VS in their signal projections. As discussed herein, coherent volume scattering (CVS, for which the phase of the incident signal is preserved during scattering) generated by in-ice neutrino interactions may similarly produce short-duration signal-like power, albeit with a slightly extended time structure, and thereby enhance neutrino detection rates, whereas incoherent (randomized phase) volume scattering (IVS) will persist for O(100 ns), appearing similar to thermal white noise and therefore reducing the measured Signal-to-Noise Ratio (SNR) of neutrino signals. Herein, we present the expected voltage profiles resulting from in-ice volume scattering as a function of the molecular scattering cross-section, for both CVS and IVS, and assess their impact on UHEN experiments. VS contributions are currently only weakly constrained by extant data; stronger limits may be obtained with dedicated calibration experiments.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"98 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Understanding the survival of gas within subhalos under various astrophysical processes is crucial for elucidating cosmic structure formation and evolution. We study the resilience of gas in subhalos, focusing on the impact of tidal and ram pressure stripping through hydrodynamic simulations. Our results uncover significant gas stripping primarily driven by ram pressure effects, which also profoundly influence the gas distribution within these subhalos. Notably, despite their vulnerability to ram pressure effects, the low-mass subhalos can play a pivotal role in influencing the observable characteristics of cosmic structures due to their large abundance. Specifically, we explore the application of our findings to the 21 cm forest, showing how the survival dynamics of gas in subhalos can modulate the 21 cm optical depth, a key probe for detecting minihalos in the pre-reionization era. Our previous study demonstrated that the 21 cm optical depth can be enhanced by the subhalos, but the effects of tidal and ram pressure stripping on the subhalo abundance have not been fully considered. In this work, we further investigate the contribution of subhalos to the 21 cm optical depth with hydrodynamic simulations, particularly highlighting the trajectories and fates of subhalos within mass ranges of 104-6M⊙h-1 in a host halo of 107M⊙h-1, and subhalos within mass range of 104-5M⊙h-1 in a host halo of 106M⊙h-1. Despite their susceptibility to ram pressure stripping, the contribution of abundant low-mass subhalos to the 21 cm optical depth is more significant than that of their massive counterparts primarily due to their greater abundance. We find that the 21 cm optical depth can be increased by a factor of approximately two due to the abundant low-mass subhalos. However, this enhancement is about twice as low as previously estimated in our earlier study, a discrepancy attributed to the effects of ram pressure stripping. Our work provides critical insights into the gas dynamics within subhalos in the early universe, highlighting their resilience against environmental stripping effects, and their impact on observable 21 cm signals.
{"title":"Survival of gas in subhalos and its impact on the 21 cm forest signals: insights from hydrodynamic simulations","authors":"Genki Naruse, Kenji Hasegawa, Kenji Kadota, Hiroyuki Tashiro and Kiyotomo Ichiki","doi":"10.1088/1475-7516/2024/10/091","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/091","url":null,"abstract":"Understanding the survival of gas within subhalos under various astrophysical processes is crucial for elucidating cosmic structure formation and evolution. We study the resilience of gas in subhalos, focusing on the impact of tidal and ram pressure stripping through hydrodynamic simulations. Our results uncover significant gas stripping primarily driven by ram pressure effects, which also profoundly influence the gas distribution within these subhalos. Notably, despite their vulnerability to ram pressure effects, the low-mass subhalos can play a pivotal role in influencing the observable characteristics of cosmic structures due to their large abundance. Specifically, we explore the application of our findings to the 21 cm forest, showing how the survival dynamics of gas in subhalos can modulate the 21 cm optical depth, a key probe for detecting minihalos in the pre-reionization era. Our previous study demonstrated that the 21 cm optical depth can be enhanced by the subhalos, but the effects of tidal and ram pressure stripping on the subhalo abundance have not been fully considered. In this work, we further investigate the contribution of subhalos to the 21 cm optical depth with hydrodynamic simulations, particularly highlighting the trajectories and fates of subhalos within mass ranges of 104-6M⊙h-1 in a host halo of 107M⊙h-1, and subhalos within mass range of 104-5M⊙h-1 in a host halo of 106M⊙h-1. Despite their susceptibility to ram pressure stripping, the contribution of abundant low-mass subhalos to the 21 cm optical depth is more significant than that of their massive counterparts primarily due to their greater abundance. We find that the 21 cm optical depth can be increased by a factor of approximately two due to the abundant low-mass subhalos. However, this enhancement is about twice as low as previously estimated in our earlier study, a discrepancy attributed to the effects of ram pressure stripping. Our work provides critical insights into the gas dynamics within subhalos in the early universe, highlighting their resilience against environmental stripping effects, and their impact on observable 21 cm signals.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"1 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/084
Chon Man Sou, Junqi Wang and Yi Wang
The inflationary universe creates particle pairs, which are entangled in their momenta due to momentum conservation. Operators involving the momenta of the fluctuations can be rewritten into pseudo-spin operators, such as the Gour-Khanna-Mann-Revzen (GKMR) pseudo-spin. Making use of these pseudo-spin operators, cosmological Bell inequalities can be formulated. The violation of these Bell inequalities indicates the quantum nature of primordial fluctuations. In this work, we focus on primordial curvature perturbations. Since curvature perturbations arise from gravity, their action includes the Gibbons-Hawking-York boundary term. We clarify the role of the boundary term in selecting suitable initial conditions for linear perturbations. After that, we proceed to the interactions of cosmological perturbations, including the bulk and boundary interaction terms, which introduce decoherence effects. These decoherence effects change the expectation value of the Bell operator, and gradually restore the Bell inequality. We describe this process by a “Bell test curve”, which offers a window around 5 e-folds for testing the quantum origin of cosmological perturbations. We also explore the possibility of extracting the information of the decoherence rate and the structure of primordial interactions from the Bell test curve.
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Pub Date : 2024-10-24DOI: 10.1088/1475-7516/2024/10/081
S. Abe, J. Abhir, A. Abhishek, F. Acero, A. Acharyya, R. Adam, A. Aguasca-Cabot, I. Agudo, A. Aguirre-Santaella, J. Alfaro, N. Alvarez-Crespo, R. Alves Batista, J.-P. Amans, E. Amato, G. Ambrosi, F. Ambrosino, E.O. Angüner, C. Aramo, C. Arcaro, L. Arrabito, K. Asano, Y. Ascasíbar, J. Aschersleben, L. Augusto Stuani, M. Backes, C. Balazs, M. Balbo, J. Ballet, A. Baquero Larriva, V. Barbosa Martins, U. Barres de Almeida, J.A. Barrio, I. Batković, R. Batzofin, J. Baxter, J. Becerra González, G. Beck, L. Beiske, R. Belmont, W. Benbow, E. Bernardini, J. Bernete, K. Bernlöhr, A. Berti, B. Bertucci, V. Beshley, P. Bhattacharjee, S. Bhattacharyya, B. Bi, N. Biederbeck, A. Biland, E. Bissaldi, J. Biteau, O. Blanch, J. Blazek, F. Bocchino, C. Boisson, J. Bolmont, L. Bonneau Arbeletche, G. Bonnoli, A. Bonollo, P. Bordas, Z. Bosnjak, E. Bottacini, C. Braiding, E. Bronzini, R. Brose, A.M. Brown, F. Brun, G. Brunelli, N. Bucciantini, A. Bulgarelli, I. Burelli, L. Burmistrov, M. Burton, A. ..
Approximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way, detected with a combination of targeted observations and surveys. A survey of the entire Galactic Plane in the energy range from a few tens of GeV to a few hundred TeV has been proposed as a Key Science Project for the upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents the status of the studies towards the Galactic Plane Survey (GPS). We build and make publicly available a sky model that combines data from recent observations of known gamma-ray emitters with state-of-the-art physically-driven models of synthetic populations of the three main classes of established Galactic VHE sources (pulsar wind nebulae, young and interacting supernova remnants, and compact binary systems), as well as of interstellar emission from cosmic-ray interactions in the Milky Way. We also perform an optimisation of the observation strategy (pointing pattern and scheduling) based on recent estimations of the instrument performance. We use the improved sky model and observation strategy to simulate GPS data corresponding to a total observation time of 1620 hours spread over ten years. Data are then analysed using the methods and software tools under development for real data. Under our model assumptions and for the realisation considered, we show that the GPS has the potential to increase the number of known Galactic VHE emitters by almost a factor of five. This corresponds to the detection of more than two hundred pulsar wind nebulae and a few tens of supernova remnants at average integral fluxes one order of magnitude lower than in the existing sample above 1 TeV, therefore opening the possibility to perform unprecedented population studies. The GPS also has the potential to provide new VHE detections of binary systems and pulsars, to confirm the existence of a hypothetical population of gamma-ray pulsars with an additional TeV emission component, and to detect bright sources capable of accelerating particles to PeV energies (PeVatrons). Furthermore, the GPS will constitute a pathfinder for deeper follow-up observations of these source classes. Finally, we show that we can extract from GPS data an estimate of the contribution to diffuse emission from unresolved sources, and that there are good prospects of detecting interstellar emission and statistically distinguishing different scenarios. Thus, a survey of the entire Galactic plane carried out from both hemispheres with CTAO will ensure a transformational advance in our knowledge of Galactic VHE source populations and interstellar emission.
{"title":"Prospects for a survey of the galactic plane with the Cherenkov Telescope Array","authors":"S. Abe, J. Abhir, A. Abhishek, F. Acero, A. Acharyya, R. Adam, A. Aguasca-Cabot, I. Agudo, A. Aguirre-Santaella, J. Alfaro, N. Alvarez-Crespo, R. Alves Batista, J.-P. Amans, E. Amato, G. Ambrosi, F. Ambrosino, E.O. Angüner, C. Aramo, C. Arcaro, L. Arrabito, K. Asano, Y. Ascasíbar, J. Aschersleben, L. Augusto Stuani, M. Backes, C. Balazs, M. Balbo, J. Ballet, A. Baquero Larriva, V. Barbosa Martins, U. Barres de Almeida, J.A. Barrio, I. Batković, R. Batzofin, J. Baxter, J. Becerra González, G. Beck, L. Beiske, R. Belmont, W. Benbow, E. Bernardini, J. Bernete, K. Bernlöhr, A. Berti, B. Bertucci, V. Beshley, P. Bhattacharjee, S. Bhattacharyya, B. Bi, N. Biederbeck, A. Biland, E. Bissaldi, J. Biteau, O. Blanch, J. Blazek, F. Bocchino, C. Boisson, J. Bolmont, L. Bonneau Arbeletche, G. Bonnoli, A. Bonollo, P. Bordas, Z. Bosnjak, E. Bottacini, C. Braiding, E. Bronzini, R. Brose, A.M. Brown, F. Brun, G. Brunelli, N. Bucciantini, A. Bulgarelli, I. Burelli, L. Burmistrov, M. Burton, A. ..","doi":"10.1088/1475-7516/2024/10/081","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/10/081","url":null,"abstract":"Approximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way, detected with a combination of targeted observations and surveys. A survey of the entire Galactic Plane in the energy range from a few tens of GeV to a few hundred TeV has been proposed as a Key Science Project for the upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents the status of the studies towards the Galactic Plane Survey (GPS). We build and make publicly available a sky model that combines data from recent observations of known gamma-ray emitters with state-of-the-art physically-driven models of synthetic populations of the three main classes of established Galactic VHE sources (pulsar wind nebulae, young and interacting supernova remnants, and compact binary systems), as well as of interstellar emission from cosmic-ray interactions in the Milky Way. We also perform an optimisation of the observation strategy (pointing pattern and scheduling) based on recent estimations of the instrument performance. We use the improved sky model and observation strategy to simulate GPS data corresponding to a total observation time of 1620 hours spread over ten years. Data are then analysed using the methods and software tools under development for real data. Under our model assumptions and for the realisation considered, we show that the GPS has the potential to increase the number of known Galactic VHE emitters by almost a factor of five. This corresponds to the detection of more than two hundred pulsar wind nebulae and a few tens of supernova remnants at average integral fluxes one order of magnitude lower than in the existing sample above 1 TeV, therefore opening the possibility to perform unprecedented population studies. The GPS also has the potential to provide new VHE detections of binary systems and pulsars, to confirm the existence of a hypothetical population of gamma-ray pulsars with an additional TeV emission component, and to detect bright sources capable of accelerating particles to PeV energies (PeVatrons). Furthermore, the GPS will constitute a pathfinder for deeper follow-up observations of these source classes. Finally, we show that we can extract from GPS data an estimate of the contribution to diffuse emission from unresolved sources, and that there are good prospects of detecting interstellar emission and statistically distinguishing different scenarios. Thus, a survey of the entire Galactic plane carried out from both hemispheres with CTAO will ensure a transformational advance in our knowledge of Galactic VHE source populations and interstellar emission.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"212 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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