The Astrophysical Journal最新文献_第9页

Improved Constraints on the Faraday Rotation toward Eight Fast Radio Bursts Using Dense Grids of Polarized Radio Galaxies

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb8e3

Ayush Pandhi, B. M. Gaensler, Ziggy Pleunis, Sebastian Hutschenreuter, Casey Law, Ryan Mckinven, Shane P. O’Sullivan, Emily B. Petroff and Tessa Vernstrom

{"title":"Improved Constraints on the Faraday Rotation toward Eight Fast Radio Bursts Using Dense Grids of Polarized Radio Galaxies","authors":"Ayush Pandhi, B. M. Gaensler, Ziggy Pleunis, Sebastian Hutschenreuter, Casey Law, Ryan Mckinven, Shane P. O’Sullivan, Emily B. Petroff and Tessa Vernstrom","doi":"10.3847/1538-4357/adb8e3","DOIUrl":"https://doi.org/10.3847/1538-4357/adb8e3","url":null,"abstract":"We present 2–4 GHz observations of polarized radio galaxies toward eight fast radio bursts (FRBs), producing grids of Faraday rotation measure (RM) sources with sky densities of 9–28 polarized sources per square degree. Using a Bayesian interpolation framework, we constrain Galactic RM fluctuations below ∼1 deg2 angular scales around the FRB positions. Despite the positions of all eight FRBs being located far from the Galactic plane, we constrain previously unresolved small-scale Galactic RM structures around six of the eight FRBs. In two of these fields, we find potential changes in the sign of the Galactic RM that are not captured by previous, sparsely sampled RM grid observations. Our Galactic RM estimate toward the FRBs differs by a few radians per square meter up to ∼40 rad m−2 from the all-sky Galactic RM map of S. Hutschenreuter et al. Extrapolating our results to the known population of polarized FRB sources, we may be incorrectly interpreting the host galaxy RM for ∼30% of the FRB source population with current RM grid observations. Measuring small-scale Galactic RM variations is crucial for identifying FRBs in low-density and weakly magnetized environments, which in turn could serve as potent probes of cosmic magnetism. This framework of reconstructing continuous Galactic RM structure from RM grid observations can be readily applied to FRBs that fall within the sky coverage of upcoming large-sky radio polarization surveys of radio galaxies, such as the Very Large Array Sky Survey and the Polarization Sky Survey of the Universe’s Magnetism.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703193","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

AT2021aeuk: A Repeating Partial Tidal Disruption Event Candidate in a Narrow-line Seyfert 1 Galaxy

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb724

Jingbo Sun, Hengxiao Guo, Minfeng Gu, Ya-Ping Li, Yongjun Chen, D. González-Buitrago, Jian-Guo Wang, Sha-Sha Li, Hai-Cheng Feng, Dingrong Xiong, Yanan Wang, Qi Yuan, Jun-jie Jin, Wenda Zhang, Hongping Deng and Minghao Zhang

{"title":"AT2021aeuk: A Repeating Partial Tidal Disruption Event Candidate in a Narrow-line Seyfert 1 Galaxy","authors":"Jingbo Sun, Hengxiao Guo, Minfeng Gu, Ya-Ping Li, Yongjun Chen, D. González-Buitrago, Jian-Guo Wang, Sha-Sha Li, Hai-Cheng Feng, Dingrong Xiong, Yanan Wang, Qi Yuan, Jun-jie Jin, Wenda Zhang, Hongping Deng and Minghao Zhang","doi":"10.3847/1538-4357/adb724","DOIUrl":"https://doi.org/10.3847/1538-4357/adb724","url":null,"abstract":"A black hole (BH) can tear apart a star that ventures within its tidal radius, producing a luminous flare as the stellar debris falls back, known as a tidal disruption event (TDE). While TDEs in quiescent galaxies are relatively well understood, identifying TDEs in active galactic nuclei (AGNs) still remains a significant challenge. We present the discovery of AT2021aeuk, a transient exhibiting dual flares within around 3 yr in a narrow-line Seyfert 1 galaxy. Multiwavelength observations triggered during the second flare in 2023 revealed an extraordinary X-ray V-shaped light curve, strongly anticorrelated with the optical light curve and accompanied by a lag of ∼40 days. This behavior is inconsistent with both supernova and pure AGN origins. In addition, a new broad component emerges in the Balmer lines during the second flare, showing a clear reverberation signal to the continuum variation. We propose that the dual flare may be linked to a repeating partial TDE (rpTDE), where the second flare results from a collision between the TDE stream and the inner accretion disk, triggering an optical flare while simultaneously partially destroying the X-ray corona. However, other mechanisms, such as a stellar-mass BH merger within an accretion disk, could produce similar phenomena, which we cannot entirely rule out. The Vera C. Rubin Observatory will be a powerful tool for further investigating the nature of such events in the future.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703107","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

Polarization Properties of 28 Repeating Fast Radio Burst Sources with CHIME/FRB

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb0bc

Cherry Ng, Ayush Pandhi, Ryan Mckinven, Alice P. Curtin, Kaitlyn Shin, Emmanuel Fonseca, B. M. Gaensler, Dylan L. Jow, Victoria Kaspi, Dongzi Li, Robert Main, Kiyoshi W. Masui, Daniele Michilli, Kenzie Nimmo, Ziggy Pleunis, Paul Scholz, Ingrid Stairs, Mohit Bhardwaj, Charanjot Brar, Tomas Cassanelli, Ronniy C. Joseph, Aaron B. Pearlman, Masoud Rafiei-Ravandi and Kendrick Smith

{"title":"Polarization Properties of 28 Repeating Fast Radio Burst Sources with CHIME/FRB","authors":"Cherry Ng, Ayush Pandhi, Ryan Mckinven, Alice P. Curtin, Kaitlyn Shin, Emmanuel Fonseca, B. M. Gaensler, Dylan L. Jow, Victoria Kaspi, Dongzi Li, Robert Main, Kiyoshi W. Masui, Daniele Michilli, Kenzie Nimmo, Ziggy Pleunis, Paul Scholz, Ingrid Stairs, Mohit Bhardwaj, Charanjot Brar, Tomas Cassanelli, Ronniy C. Joseph, Aaron B. Pearlman, Masoud Rafiei-Ravandi and Kendrick Smith","doi":"10.3847/1538-4357/adb0bc","DOIUrl":"https://doi.org/10.3847/1538-4357/adb0bc","url":null,"abstract":"As part of the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) project, we report 41 new rotation measures (RMs) from 20 repeating fast radio bursts (FRBs) obtained between 2019 and 2023 for which no previous RM was determined. We also report 22 additional RM measurements for eight further repeating FRBs. We observe temporal RM variations in practically all repeating FRBs. Repeaters appear to be separated into two categories: those with dynamic and those with stable RM environments, differentiated by the ratios of RM standard deviations to the averaged RM magnitudes. Sources from stable RM environments likely have small RM contributions from the interstellar medium of their host galaxies, whereas sources from dynamic RM environments share some similarities with Galactic pulsars in eclipsing binaries but appear distinct from solitary pulsars in the Galactic centre. We observe a new stochastic, secular, and again stochastic trend in the temporal RM variation of FRB 20180916B, which does not support binary orbit modulation being its cause. We highlight two more repeaters that show RM sign change, namely FRBs 20290929C and 20190303A. We perform an updated comparison of polarization properties between repeating and nonrepeating FRBs, which show a marginal dichotomy in their distribution of electron-density-weighted parallel-component line-of-sight magnetic fields.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703057","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

High-energy Jet Emission from GRS 1758–258 and 1E 1740.7–2942 with INTEGRAL?

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adba49

James Rodi, Angela Bazzano and Pietro Ubertini

{"title":"High-energy Jet Emission from GRS 1758–258 and 1E 1740.7–2942 with INTEGRAL?","authors":"James Rodi, Angela Bazzano and Pietro Ubertini","doi":"10.3847/1538-4357/adba49","DOIUrl":"https://doi.org/10.3847/1538-4357/adba49","url":null,"abstract":"GRS 1758–258 and 1E 1740.7–2942 are two long-known persistent black hole binaries in the Galactic center region. Using the International Gamma-Ray Astrophysics Laboratory (INTEGRAL)'s extensive monitoring of the Galactic center and bulge, we studied their temporal and spectral evolutions in the 30–610 keV energy range from 2003 March through 2022 April with the Imager on Board INTEGRAL/INTEGRAL Soft Gamma-ray Imager gamma-ray telescope. Our analyses found that the sources typically had Comptonized spectra, though not always with the same parameters. The spectral states with more than 8 Ms of observation time show deviations from a Comptonized spectrum above ∼200 keV or a “hard tail” that extends up to at least 600 keV. The origin of this component remains debated, with the most popular scenarios being synchrotron emission from the jet or Comptonization in a hybrid thermal/nonthermal plasma. Anyway, the GRS 1758–258 and 1E 1740.7–2942 spectra are acceptably described by CompTT+po (jet) and Eqpair (hybrid Comptonization) scenarios. To differentiate between the two scenarios, we calculated the Spearman correlation coefficient comparing 30–50 keV count rates with those in higher energy bands (50–100, 100–300, and 300–600 keV). The count rates below 300 keV are strongly correlated, indicating those photons arise from the same physical process. Above 300 keV the count rates are either anticorrelated or not correlated with the 30–50 keV count rates for GRS 1758–258, which suggests that the photons originate from a different physical process. For 1E 1740.7–2942, the level of correlation is unclear due to scatter in the data points. However, the 300–600 keV count rates are consistent with a constant value. This disfavors the hybrid Comptonization scenario for both sources.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703110","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

Formation of Jet-driven Forced Reconnection Region and Associated Plasma Blobs in a Prominence Segment

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb8db

Sudheer K. Mishra, A. K. Srivastava, S. P. Rajaguru and P. Jelínek

{"title":"Formation of Jet-driven Forced Reconnection Region and Associated Plasma Blobs in a Prominence Segment","authors":"Sudheer K. Mishra, A. K. Srivastava, S. P. Rajaguru and P. Jelínek","doi":"10.3847/1538-4357/adb8db","DOIUrl":"https://doi.org/10.3847/1538-4357/adb8db","url":null,"abstract":"We use data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to study the most likely formation of a forced reconnection region and associated plasma blobs, triggered by jetlike structures in a prominence segment. Around 05:44 UT on 2017 December 16th, hot jetlike structures lifted from a nearby active region and fell obliquely on one side of the prominence segment with velocities of ≈45–65 km s−1. These eruptions compressed the boundaries of the prominence and flux rope, forming an elongated reconnection region with inflow velocities of 47–52 km s−1 and 36–49 km s−1 in the projected plane. A thin, elongated reconnection region was formed, with multiple magnetic plasma blobs propagating bidirectionally at velocities of 91–178 km s−1. These dense blobs, associated with ongoing reconnection, may also be linked to the onset of Kelvin–Helmholtz (K-H) instability. The blobs are attributed to plasmoids, moving at slower speeds (91–178 km s−1) due to the high density in the prominence segment. The dimensionless reconnection rate varied from 0.57–0.28, 0.53–0.26, and 0.41–0.20, indicating reconnection rate enhancement and supporting the forced reconnection scenario. After reconnection, the prominence plasma heated to 6 MK, releasing significant thermal energy (≈5.4 × 1027 erg), which drained cool prominence plasma and heated it to coronal temperatures. The ubiquity of jets and outflows in the solar atmosphere makes the aforementioned reconnection and possible coexistence of K-H instability potentially important for the magnetic energy release and heating in the solar atmosphere.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703111","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

Accelerated Emergence of Evolved Galaxies in Early Overdensities at z ∼ 5.7

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb30f

Takahiro Morishita, Zhaoran Liu, Massimo Stiavelli, Tommaso Treu, Michele Trenti, Nima Chartab, Guido Roberts-Borsani, Benedetta Vulcani, Pietro Bergamini, Marco Castellano and Claudio Grillo

{"title":"Accelerated Emergence of Evolved Galaxies in Early Overdensities at z ∼ 5.7","authors":"Takahiro Morishita, Zhaoran Liu, Massimo Stiavelli, Tommaso Treu, Michele Trenti, Nima Chartab, Guido Roberts-Borsani, Benedetta Vulcani, Pietro Bergamini, Marco Castellano and Claudio Grillo","doi":"10.3847/1538-4357/adb30f","DOIUrl":"https://doi.org/10.3847/1538-4357/adb30f","url":null,"abstract":"We report the identification of two galaxy overdensities at z ∼ 5.7 in the sightline of the galaxy cluster A2744. These overdensities consist of 25 and 17 member galaxies, spectroscopically confirmed with JWST NIRSpec micro-shutter assembly and NIRCam/WFSS. Each overdensity has a total stellar mass of ∼2 × 1010M⊙ and a star formation rate of ∼200 M⊙ yr−1 within a central region of radius R = 2 Mpc (physical). The sensitive PRISM spectra allow us to identify six galaxies that show weak Hα + [N ii] emissions within the overdensities (25% ± 7%), whereas the fraction of such galaxies is found significantly lower (6% ± 2%) in field samples of the equivalent redshift range. These weak emission line galaxies, dubbed as wELGs, exhibit a strong continuum break at the 4000 Å rest frame, a characteristic feature of evolved stellar populations. The high observed fraction of wELGs in the two overdensities is consistent with the idea that high-density environments are an ideal site where galaxies can accelerate their evolutionary pace compared to field analogs. Our study pinpoints an early onset of environmental effects, already important within one billion years after the Big Bang, and provides a complementary perspective on the emergence of quenched, massive galaxies at lower redshifts. Potential contributions from black hole accretion feedback to the reduction in star formation activity are discussed, but the connection to the local environments remains unclear.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703058","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

Unraveling Visible Spectra of S-type Stars: The f3Δ–a3Δ (α System) and e3Π–a3Δ (β System) Band Systems of ZrO 揭示S型恒星的可见光谱：氧化锆的 f3Δ-a3Δ（α 系统）和 e3Π-a3Δ（β 系统）波段系统

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adbd3f

Manish Bhusal, Peter F Bernath and Jacques Liévin

引用次数: 0

Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adb627

Keshav Aggarwal, R. K. Choudhary, Abhirup Datta, Roopa M. V. and Bijoy K. Dai

{"title":"Insights into Solar Wind Flow Speeds from the Coronal Radio Occultation Experiment: Findings from the Indian Mars Orbiter Mission","authors":"Keshav Aggarwal, R. K. Choudhary, Abhirup Datta, Roopa M. V. and Bijoy K. Dai","doi":"10.3847/1538-4357/adb627","DOIUrl":"https://doi.org/10.3847/1538-4357/adb627","url":null,"abstract":"Using data collected by the Indian Mars Orbiter Mission (MOM) in 2021 October, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is introduced to directly relate these two parameters. The study focuses on observations conducted from 2021 October 2 to October 14, a relatively quiet phase of solar cycle 25. The analysis targeted the coronal region within heliocentric distances of 5–8 R⊙, near the ecliptic plane. In this region, solar wind velocities ranged from 100 to 150 km s−1, while electron densities were on the order of 1010 m−3. We also compared our results with electron density observations and models derived from previous studies. Though the decrease in the electron densities with respect to increasing heliocentric distance matches quite well with the theoretical models, MOM estimates fall at the lower edge of the distribution. This difference may be attributed to the prolonged weak solar activity during the MOM observations, in contrast to prior studies conducted during periods of comparatively higher solar activity in earlier solar cycles.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703105","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

Extracting the Temperature Analytically in Hydrodynamics Simulations with Gas and Radiation Pressure

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adbd10

Thomas W. Baumgarte and Stuart L. Shapiro

引用次数: 0

Where Has All the R-process Gone? Timescales for Gamma-Ray Burst Kilonovae to Enrich Their Host Galaxies

The Astrophysical Journal Pub Date : 2025-03-26 DOI: 10.3847/1538-4357/adbb6a

Anya E. Nugent, Alexander P. Ji, Wen-fai Fong, Hilay Shah and Freeke van de Voort

{"title":"Where Has All the R-process Gone? Timescales for Gamma-Ray Burst Kilonovae to Enrich Their Host Galaxies","authors":"Anya E. Nugent, Alexander P. Ji, Wen-fai Fong, Hilay Shah and Freeke van de Voort","doi":"10.3847/1538-4357/adbb6a","DOIUrl":"https://doi.org/10.3847/1538-4357/adbb6a","url":null,"abstract":"Neutron star (NS) mergers are currently the only observed source of r-process production in the Universe. Yet, it is unclear how much r-process mass from these mergers is incorporated into star-forming gas to enrich stars. This is crucial to consider as all other r-process mass estimates in the Universe beyond Earth are based on stellar r-process abundances. Here, we explore the extent to which merger location and host-galaxy properties affect the incorporation of r-process elements into star-forming gas, and quantify an “enrichment” timescale to account for this process. To put this timescale in context, we analyze a population of 12 gamma-ray bursts (GRBs) with probable associations to r-process kilonovae (GRB-KNe) and 74 short GRBs without claimed KNe, including new nonparametric star formation histories for the GRB-KN hosts. We find the enrichment timescales for this sample are between ≈7 Myr and 1.6 Gyr, suggesting that environmental enrichment is delayed from NS merger occurrence. Moreover, we find a correlation between the amount of environmental enrichment from a single event and increasing host specific star formation rate (sSFR), and little correlation with stellar mass and GRB galactocentric offset. Environments with low sSFRs (<10−10.5 yr−1), which comprise 18% of short-GRB hosts and the host of GW170817, will have little to no capacity for stellar enrichment. Our results indicate that not all r-process from NS mergers is incorporated into newly forming stars, and instead some remains “lost” to the circumgalactic medium or intergalactic medium. Future studies should consider these losses to understand the total contribution from NS mergers to the Universe’s r-process budget.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703116","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