The Astrophysical Journal最新文献_第2页

Does DESI DR2 Challenge ΛCDM Paradigm? DESI DR2是否挑战ΛCDM范式？

The Astrophysical Journal Pub Date : 2025-10-14 DOI: 10.3847/1538-4357/ae0458

Himanshu Chaudhary, Salvatore Capozziello, Vipin Kumar Sharma and Ghulam Mustafa

{"title":"Does DESI DR2 Challenge ΛCDM Paradigm?","authors":"Himanshu Chaudhary, Salvatore Capozziello, Vipin Kumar Sharma and Ghulam Mustafa","doi":"10.3847/1538-4357/ae0458","DOIUrl":"https://doi.org/10.3847/1538-4357/ae0458","url":null,"abstract":"Although the debate about the systematic errors of DESI DR1 is still open, recent DESI DR2 is consistent with DESI DR1 and further strengthens the results of DESI DR1. In our analysis, both the LRG1 point at zeff = 0.510 and the LRG3+ELG1 point at zeff = 0.934 are in tension with the ΛCDM-anchored value of Ωm inferred from Planck and the Type Ia supernovae compilations Pantheon+, Union3, and DES-SN5YR. For luminous red galaxy 1 (LRG1) the tensions are 2.42σ, 1.91σ, 2.19σ, and 2.99σ, respectively; for LRG3+emission line galaxy 1 (ELG1) they are 2.60σ, 2.24σ, 2.51σ, and 2.96σ, respectively. From low to high redshift bins, DESI DR2 shows improved consistency relative to DESI DR1: the Ωm tension decreases from 2.20σ to 1.84σ. However, DESI DR2 alone does not provide decisive evidence against the ΛCDM model, and the apparent signal is largely driven by specific tracers, LRG1 and LRG2. In the ω0ωaCDM analysis, including all tracers yields a posterior mean with ω0 > −1, which aligns with scenarios of dynamical dark energy as a potential explanation and suggests that the DESI DR2 challenges the ΛCDM paradigm. While removing LRG1 and/or LRG2 fully restores ΛCDM concordance (i.e., ω0 → −1), we also find , indicating LRG1 drives the apparent dynamical dark energy trend more strongly. Model selection using the natural log Bayes factor shows weak evidence for ΛCDM when LRG1, LRG2, or both are removed, and it is inconclusive for the full sample; thus, the data do not require the extra ωa freedom, and the apparent ω0 > −1 preference should be interpreted cautiously as a manifestation of the ω0–ωa degeneracy under limited per tracer information.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145289384","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}

引用次数: 0

Signals of Bursts from the Very Early Universe 早期宇宙爆发的信号

The Astrophysical Journal Pub Date : 2025-10-14 DOI: 10.3847/1538-4357/ae01a4

Leo Stodolsky and Joseph Silk

引用次数: 0

Natal Kick by Early-asymmetrical Pairs of Jets to the Neutron Star of Supernova Remnant S147 超新星遗迹S147中子星早期不对称射流对的出生踢

The Astrophysical Journal Pub Date : 2025-10-14 DOI: 10.3847/1538-4357/ae0332

Dmitry Shishkin, Ealeal Bear and Noam Soker

{"title":"Natal Kick by Early-asymmetrical Pairs of Jets to the Neutron Star of Supernova Remnant S147","authors":"Dmitry Shishkin, Ealeal Bear and Noam Soker","doi":"10.3847/1538-4357/ae0332","DOIUrl":"https://doi.org/10.3847/1538-4357/ae0332","url":null,"abstract":"We analyze the bipolar morphology of the jet-shaped core-collapse supernova remnant (CCSNR) S147 and its neutron star (NS) kick velocity, and suggest that two pairs of unequal, opposite jets contributed to the NS kick velocity. This kick by early asymmetrical pairs (kick-BEAP) of jets mechanism operates within the framework of the jittering jets explosion mechanism (JJEM). We examine the prominent pair of large ears and, based on their flat structure rather than the more common conical structure of ears, conclude that two pairs of jets close in angle inflated the two opposite ears. We connect two opposite X-ray bright zones by an additional axis to create the full point-symmetric morphology of CCSNR S147. We propose that the two unequal jets that formed the X-ray bright zones imparted the first kick-BEAP, while the two pairs of jets that formed the ears imparted the second kick-BEAP. The two kick velocities are of about equal magnitude of ≃450 km s−1, which implies very energetic jets. Such jets can excite gravitational waves that present detectors can detect from the Galaxy and the Magellanic Clouds. We use the morphology we identify to estimate the CCSNR age at 23,000 yr. Our results strengthen the JJEM.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145289232","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}

引用次数: 0

Evolution of Low Surface Brightness Ultrathin Galaxies: The Role of Dark Matter Halo and Bar Formation on Disk Thickness 低表面亮度超薄星系的演化：暗物质晕和棒状形成对星系盘厚度的作用

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/ae0991

K. Aditya and Arunima Banerjee

{"title":"Evolution of Low Surface Brightness Ultrathin Galaxies: The Role of Dark Matter Halo and Bar Formation on Disk Thickness","authors":"K. Aditya and Arunima Banerjee","doi":"10.3847/1538-4357/ae0991","DOIUrl":"https://doi.org/10.3847/1538-4357/ae0991","url":null,"abstract":"We investigate how stellar disks sustain their ultrathin structure throughout their evolution. We follow the evolution of ultrathin stellar disks with varying dark matter (DM) halo concentration (c) using collisionless N-body simulations with AREPO. We test models embedded in steep (c = 12), shallow (c = 2), and intermediate (c = 6) DM concentrations. Our models match the observed structural properties of the stellar disk in the low surface brightness (LSB) ultrathin galaxy FGC 2366, specifically its surface brightness, disk scalelength, and vertical thinness (hz/RD = 0.1), while excluding gas, allowing us to isolate the effects of DM. The internal disk heating mechanism driven by bars is suppressed in the LSB ultrathin stellar disks regardless of the DM concentration. The ratio of disk thickness (hz) to scalelength (RD) remains constant at ≤0.1 throughout their evolution. To clearly establish that the LSB nature of stellar disks is the key to preventing disk thickening, we construct the initial conditions by increasing the stellar mass fraction from fs ∼ 0.01 to 0.02 and 0.04, respectively, while keeping the total mass equal to 1011M⊙ and hz/RD ≤ 0.1 unchanged. We find that models with a higher stellar mass fraction embedded in a shallow DM potential (c = 2) form bars and undergo significant disk thickening (hz/RD ≫ 0.1) concurrent with the bar growth. We conclude that if the LSB disks are thin to begin with, they remain so throughout their evolution in isolation, regardless of the concentration of the DM halo.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282898","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}

引用次数: 0

Rotational Spectroscopy and Tentative Interstellar Detection of 3-hydroxypropanal (HOCH2CH2CHO) in the G+0.693-0.027 Molecular Cloud G+0.693-0.027分子云中3-羟基丙烷（HOCH2CH2CHO）的旋转光谱和星际探测

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/adfc62

Zachary T. P. Fried, Roman A. Motiyenko, Miguel Sanz-Novo, Lucie Kolesniková, Jean-Claude Guillemin, Laurent Margulès, Tereza Uhlíková, Arnaud Belloche, Jes K. Jørgensen, Martin S. Holdren, Ci Xue, Štěpán Urban, Izaskun Jiménez-Serra, Victor M. Rivilla and Brett A. McGuire

{"title":"Rotational Spectroscopy and Tentative Interstellar Detection of 3-hydroxypropanal (HOCH2CH2CHO) in the G+0.693-0.027 Molecular Cloud","authors":"Zachary T. P. Fried, Roman A. Motiyenko, Miguel Sanz-Novo, Lucie Kolesniková, Jean-Claude Guillemin, Laurent Margulès, Tereza Uhlíková, Arnaud Belloche, Jes K. Jørgensen, Martin S. Holdren, Ci Xue, Štěpán Urban, Izaskun Jiménez-Serra, Victor M. Rivilla and Brett A. McGuire","doi":"10.3847/1538-4357/adfc62","DOIUrl":"https://doi.org/10.3847/1538-4357/adfc62","url":null,"abstract":"We synthesized the astrochemically relevant molecule 3-hydroxypropanal (HOCH2CH2CHO) and subsequently measured and analyzed its rotational spectrum in several frequency regions ranging from 130 to 485 GHz. We analyzed the ground vibrational state as well as the two perturbed lowest-lying vibrationally excited states. With the resulting rotational parameters, we searched for this molecule in the Sagittarius B2(N) and NGC 6334I hot cores, the IRAS 16293-2422B hot corino, and the G+0.693-0.027 and TMC-1 molecular clouds. Rotational emission of 3-hydroxypropanal was tentatively detected toward G+0.693-0.027, and a column density of (8.6 ±1.4) × 1012 cm−2 was determined. However, this molecule was not detected in the other sources that were investigated. The chemical implications of this tentative discovery are analyzed, and several potential chemical formation pathways of this species are discussed.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"127 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282890","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}

引用次数: 0

A High-precision Dynamical Model of Callisto: Incorporating Rotation Effects within Multilayer Internal Structure Models 木卫四的高精度动力学模型：多层内部结构模型中包含旋转效应

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/adfe65

Kai Huang, Yongzhang Yang, Yuhao Chen, Yining Zhang and Yuqiang Li

{"title":"A High-precision Dynamical Model of Callisto: Incorporating Rotation Effects within Multilayer Internal Structure Models","authors":"Kai Huang, Yongzhang Yang, Yuhao Chen, Yining Zhang and Yuqiang Li","doi":"10.3847/1538-4357/adfe65","DOIUrl":"https://doi.org/10.3847/1538-4357/adfe65","url":null,"abstract":"China is planning to launch the “Tianwen-4” mission around the year 2030, with its aim being the exploration of Jupiter and its moon, Callisto. Within the realm of deep space exploration, the accuracy of ephemerides is of great importance. Current ephemerides employ a simplified rotation model for Callisto, which this study addresses by proposing a novel dynamical model. This model enhances the existing orbital dynamics by integrating Callisto’s rotational motions influenced by gravitational torques from the Sun, Jupiter, and other Galilean moons within an inertial frame, capturing the intricate coupling between Callisto’s orbital and rotational dynamics. The study establishes a full dynamical model by deriving analytical expressions for this coupling and developing an adjustment model for data fitting using precise orbit determination methods. Furthermore, the influence of tidal effects on Callisto’s motion is investigated, considering its multilayered internal structure. Results demonstrate that the difference between the newly established full model and the model in current ephemerides is on the order of tens of meters. When calculating the impact of different internal structures of Callisto on its orbit, the influence of three-layered and two-layered structures is on the order of meters, suggesting that the development of a high-precision dynamical model requires additional constraints on the internal structure of Callisto. This research provides a novel alternative for a new generation of precise numerical ephemerides for Callisto. Additionally, these findings provide a testing platform for the data from the “Tianwen-4” mission.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282893","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}

引用次数: 0

Estimation of Effective Viscosity to Quantify Collisional Behavior in Collisionless Plasma 估算有效粘度以量化无碰撞等离子体中的碰撞行为

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/ae08b4

Subash Adhikari, Carlos A. González, Yan Yang, 艳杨, Sean Oughton, Francesco Pecora, Riddhi Bandyopadhyay and William H. Matthaeus

{"title":"Estimation of Effective Viscosity to Quantify Collisional Behavior in Collisionless Plasma","authors":"Subash Adhikari, Carlos A. González, Yan Yang, 艳杨, Sean Oughton, Francesco Pecora, Riddhi Bandyopadhyay and William H. Matthaeus","doi":"10.3847/1538-4357/ae08b4","DOIUrl":"https://doi.org/10.3847/1538-4357/ae08b4","url":null,"abstract":"While dissipation in collisional plasma is defined in terms of viscosity and resistivity, the exact functional form of dissipation, i.e., the so-called dissipation function in nearly collisionless plasma, is unknown. Nevertheless, previous studies have suggested that there exists viscous-like energy conversion in collisionless plasma with scaling characteristics analogous to collisional plasma, and in particular that the average dissipation is proportional to the square of the rate of strain as in hydrodynamics. In this study, using 2.5D kinetic particle-in-cell (PIC) simulation of collisionless plasma turbulence, we provide an estimate of effective viscosity at each scale, obtained via a scale-filtering approach. We then compare the turbulent dynamics of the PIC simulation with that from MHD and two-fluid simulations in which the viscosity is equal to the effective viscosity estimate obtained from the PIC simulation. We find that the global behavior in these MHD and two-fluid simulations has a striking similarity to that in their kinetic/PIC counterpart. In addition, we explore the scale dependence of the effective viscosity and discuss implications of this approach for space plasmas.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282899","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}

引用次数: 0

Central Massive Black Holes Are Not Ubiquitous in Local Low-mass Galaxies 中心大质量黑洞在局部低质量星系中并不普遍

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/ae06a1

Fan Zou, Elena Gallo, Anil C. Seth, Edmund Hodges-Kluck, David Ohlson, Tommaso Treu, Vivienne F. Baldassare, W. N. Brandt, Jenny E. Greene, Piero Madau, Dieu D. Nguyen, Richard M. Plotkin, Amy E. Reines, Alberto Sesana, Jong-Hak Woo and Jianfeng Wu

{"title":"Central Massive Black Holes Are Not Ubiquitous in Local Low-mass Galaxies","authors":"Fan Zou, Elena Gallo, Anil C. Seth, Edmund Hodges-Kluck, David Ohlson, Tommaso Treu, Vivienne F. Baldassare, W. N. Brandt, Jenny E. Greene, Piero Madau, Dieu D. Nguyen, Richard M. Plotkin, Amy E. Reines, Alberto Sesana, Jong-Hak Woo and Jianfeng Wu","doi":"10.3847/1538-4357/ae06a1","DOIUrl":"https://doi.org/10.3847/1538-4357/ae06a1","url":null,"abstract":"The black hole occupation fraction (focc) defines the fraction of galaxies that harbor central massive black holes (MBHs), irrespective of their accretion activity level. While it is widely accepted that focc is nearly 100% in local massive galaxies with stellar masses M⋆ ≳ 1010M⊙, it is not yet clear whether MBHs are ubiquitous in less-massive galaxies. In this work, we present new constraints on focc based on over 20 yr of Chandra imaging data for 1606 galaxies within 50 Mpc. We employ a Bayesian model to simultaneously constrain focc and the specific accretion-rate distribution function, p(λ), where the specific accretion rate is defined as λ = LX/M⋆, where LX is the MBH accretion luminosity in the 2–10 keV range. Notably, we find that p(λ) peaks around ; above this value, p(λ) decreases with increasing λ, following a power law that smoothly connects with the probability distribution of bona fide active galactic nuclei. We also find that the occupation fraction decreases dramatically with decreasing M⋆: in high-mass galaxies (M⋆ ≈ 1011−12 M⊙), the occupation fraction is >93% (a 2σ lower limit), and then declines to (1σ errors) between M⋆ ≈ 109−10 M⊙, and to in the dwarf galaxy regime between M⋆ ≈ 108−9 M⊙. Our results have significant implications for the normalization of the MBH mass function over the mass range most relevant for tidal disruption events, extreme mass ratio inspirals, and MBH merger rates that upcoming facilities are poised to explore.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282896","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}

引用次数: 0

Searching for Continuous Gravitational Waves in the Parkes Pulsar Timing Array Data Release 3 在帕克斯脉冲星定时阵列中寻找连续引力波

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/ae0719

Shi-Yi Zhao, Zu-Cheng Chen, Jacob Cardinal Tremblay, Boris Goncharov, Xing-Jiang Zhu, N. D. Ramesh Bhat, Małgorzata Curyło, Shi Dai, Valentina Di Marco, Hao Ding, George Hobbs, Agastya Kapur, Wenhua Ling, Tao Liu, Rami Mandow, Saurav Mishra, Daniel J. Reardon, Christopher J Russell, Ryan M. Shannon, Shuangqiang Wang, Lei Zhang and Andrew Zic

{"title":"Searching for Continuous Gravitational Waves in the Parkes Pulsar Timing Array Data Release 3","authors":"Shi-Yi Zhao, Zu-Cheng Chen, Jacob Cardinal Tremblay, Boris Goncharov, Xing-Jiang Zhu, N. D. Ramesh Bhat, Małgorzata Curyło, Shi Dai, Valentina Di Marco, Hao Ding, George Hobbs, Agastya Kapur, Wenhua Ling, Tao Liu, Rami Mandow, Saurav Mishra, Daniel J. Reardon, Christopher J Russell, Ryan M. Shannon, Shuangqiang Wang, Lei Zhang and Andrew Zic","doi":"10.3847/1538-4357/ae0719","DOIUrl":"https://doi.org/10.3847/1538-4357/ae0719","url":null,"abstract":"We present results from an all-sky search for continuous gravitational waves from individual supermassive binary black holes using the third data release of the Parkes Pulsar Timing Array (PPTA). Even though we recover a common-spectrum stochastic process, potentially induced by a nanohertz gravitational-wave background, we find no evidence of continuous waves. Therefore, we place upper limits on the gravitational-wave strain amplitude: in the most sensitive frequency range around 10 nHz, we obtain a sky-averaged 95% credibility upper limit of ≈ 7 × 10−15. Our search is sensitive to supermassive binary black holes with a chirp mass of ≥109M⊙ up to a luminosity distance of 50 Mpc for our least sensitive sky direction and 200 Mpc for the most sensitive direction. This work provides at least 4 times better sensitivity in the 1–200 nHz frequency band than our last search based on the PPTA’s first data release. We expect that PPTA will continue to play a key role in detecting continuous gravitational waves in the exciting era of nanohertz gravitational-wave astronomy.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282897","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}

引用次数: 0

Long-term Simultaneous 2.25/8.60 GHz Monitoring of the Newly Discovered Repeating FRB 20240114A 新发现重复射电暴20240114A的2.25/8.60 GHz长期同步监测

The Astrophysical Journal Pub Date : 2025-10-13 DOI: 10.3847/1538-4357/adfece

Xiao-Wei Wang, 啸威王, Zhen Yan, 振闫, Zhi-Qiang Shen, 志强沈, Ke-Jia Lee, 柯伽李, Ya-Jun Wu, 亚军吴, Rong-Bing Zhao, 融冰赵, Jie Liu, 杰刘, Rui Wang, 睿王, Kuo Liu, 阔刘, Yuan-Chuan Zou, 远川邹, Zhi-Peng Huang, 志鹏黄, Chu-Yuan Zhang, 楚原张, Fan Yang, 帆杨, Zhen-Long Liao, 振龙廖, Yang-Yang Lin and 扬洋林

{"title":"Long-term Simultaneous 2.25/8.60 GHz Monitoring of the Newly Discovered Repeating FRB 20240114A","authors":"Xiao-Wei Wang, 啸威王, Zhen Yan, 振闫, Zhi-Qiang Shen, 志强沈, Ke-Jia Lee, 柯伽李, Ya-Jun Wu, 亚军吴, Rong-Bing Zhao, 融冰赵, Jie Liu, 杰刘, Rui Wang, 睿王, Kuo Liu, 阔刘, Yuan-Chuan Zou, 远川邹, Zhi-Peng Huang, 志鹏黄, Chu-Yuan Zhang, 楚原张, Fan Yang, 帆杨, Zhen-Long Liao, 振龙廖, Yang-Yang Lin and 扬洋林","doi":"10.3847/1538-4357/adfece","DOIUrl":"https://doi.org/10.3847/1538-4357/adfece","url":null,"abstract":"We report on the simultaneous monitoring of the repeating fast radio burst (FRB) 20240114A at 2.25 and 8.60 GHz, conducted 66 times between 2024 January 29 and 2025 February 15 with the Shanghai Tianma Radio Telescope. In about 180 hr of observation, we detected 155 bursts at 2.25 GHz above a fluence threshold of 0.72 Jy ms but none at 8.60 GHz above a fluence threshold of 0.27 Jy ms. FRB 20240114A exhibited frequency-dependent activity, as evidenced by the nondetections in 14.3 hr of observations at 2.25 GHz prior to 2024 February 24, despite its reported activity below 2 GHz. In contrast to its low-activity state reported below 1.4 GHz between 2024 June and December, FRB 20240114A exhibited high activity at 2.25 GHz in 2024 July with a mean burst rate of , followed by a low-activity state. We also detected a short-term reactivation at 2.25 GHz around 2025 January 20, about 2 weeks after renewed activity was reported below 1.4 GHz by other telescopes. The median burst width at 2.25 GHz is 3 ms, which is narrower than that at lower frequencies. The waiting time distribution peaks at 1019 s, and bursts arrive on hourly timescales consistent with a Poisson process. The isotropic-equivalent energy of the bursts spans 1037–1039 erg. The distribution of burst energy above the completeness threshold (7.5 × 1037 erg) follows a power-law relation with an index of γ = −1.20 ± 0.03 ± 0.02. Finally, we find that FRB 20240114A is at least 2 orders of magnitude less active at 8.60 GHz than at 2.25 GHz, and we constrain the broadband spectra of the detected bursts.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282892","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}

引用次数: 0