Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adadef
Jean-Luc Atteia, Laurent Bouchet, Jean-Pascal Dezalay, Francis Fortin, Olivier Godet, Sébastien Guillot, Alain Klotz, Frédéric Daigne, Robert Mochkovitch and Damien Turpin
Gamma-ray bursts (GRBs) are often referred to as the most luminous explosions in the Universe, due to their short and highly luminous prompt emission. This apparent luminosity, however, does not reflect the true energy budget of the prompt emission, which is strongly beamed. Accurate estimations of the energy radiated during the prompt phase require taking the geometry of GRB jets into account, which remains poorly known. Nevertheless, one may establish the distribution of well-measured quantities, like Eiso, the GRB isotropic equivalent energy, which encrypts crucial information about GRB jets, with the aim of providing constraints on the jet's radiated energy. In this work, we study the bright end of the GRB isotropic equivalent energy distribution (hereafter called “apparent energy”), using an updated sample of 185 apparently energetic GRBs with Eiso ≥ 1053 erg. This new sample includes GRB 221009A, allowing us to discuss this apparently superenergetic GRB in the context of the general Eiso distribution of long GRBs. We describe the construction of the sample and compare three fits of the Eiso distribution with a simple power law, a cutoff power law, and a broken power law. Our study confirms the existence of a cutoff around Eiso = 4 × 1054 erg, even when GRB 221009A is included in the sample. Based on this finding, we discuss the possible reasons behind the rapid decrease in the number of apparently energetic gamma-ray bursts beyond Eiso = 4 × 1054 erg and the interpretation of GRB 221009A, the most apparently energetic GRB detected to date, in this context.
{"title":"GRB 221009A and the Apparently Most Energetic Gamma-Ray Bursts","authors":"Jean-Luc Atteia, Laurent Bouchet, Jean-Pascal Dezalay, Francis Fortin, Olivier Godet, Sébastien Guillot, Alain Klotz, Frédéric Daigne, Robert Mochkovitch and Damien Turpin","doi":"10.3847/1538-4357/adadef","DOIUrl":"https://doi.org/10.3847/1538-4357/adadef","url":null,"abstract":"Gamma-ray bursts (GRBs) are often referred to as the most luminous explosions in the Universe, due to their short and highly luminous prompt emission. This apparent luminosity, however, does not reflect the true energy budget of the prompt emission, which is strongly beamed. Accurate estimations of the energy radiated during the prompt phase require taking the geometry of GRB jets into account, which remains poorly known. Nevertheless, one may establish the distribution of well-measured quantities, like Eiso, the GRB isotropic equivalent energy, which encrypts crucial information about GRB jets, with the aim of providing constraints on the jet's radiated energy. In this work, we study the bright end of the GRB isotropic equivalent energy distribution (hereafter called “apparent energy”), using an updated sample of 185 apparently energetic GRBs with Eiso ≥ 1053 erg. This new sample includes GRB 221009A, allowing us to discuss this apparently superenergetic GRB in the context of the general Eiso distribution of long GRBs. We describe the construction of the sample and compare three fits of the Eiso distribution with a simple power law, a cutoff power law, and a broken power law. Our study confirms the existence of a cutoff around Eiso = 4 × 1054 erg, even when GRB 221009A is included in the sample. Based on this finding, we discuss the possible reasons behind the rapid decrease in the number of apparently energetic gamma-ray bursts beyond Eiso = 4 × 1054 erg and the interpretation of GRB 221009A, the most apparently energetic GRB detected to date, in this context.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443267","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adaf9f
Zhijun Tu, Shu Wang, Xiaodian Chen and Jifeng Liu
We report the spectroscopic identification of three brown dwarf candidates—o005_s41280, o006_s00089, and o006_s35616—discovered in RUBIES using James Webb Space Telescope (JWST) Near-Infrared Spectrograph PRISM/CLEAR spectroscopy. We fit these sources with multiple substellar atmosphere models and present the atmospheric parameters, including effective temperature (Teff), surface gravity, and other derived properties. The results suggest that o005_s41280 and o006_s35616, with Teff in the ranges of 2100–2300 K and 1800–2000 K, respectively, are likely L dwarfs, while o006_s00089, with Teff < 1000 K, is consistent with a late T dwarf classification. The best-fit model spectra provide a reasonable match to the observed spectra. However, distinct residuals exist in the Y, J, and H bands for the two L dwarf candidates, particularly for o006_s35616. Incorporating the extinction parameter into the fitting process can significantly reduce these residuals. The distance estimates indicate that these candidates are about 2 kpc away. The analysis of the color–color diagram using multiple JWST NIRcam photometry suggests that cooler T dwarfs, such as o006_s00089, overlap with little red dots, while hotter L dwarfs, like o005_s41280 and o006_s35616, tend to contaminate the high-redshift galaxy cluster. These findings suggest a brown dwarf contamination rate of approximately 0.1% in extragalactic deep field surveys, with L dwarfs being more frequently detected than cooler T and Y dwarfs.
{"title":"Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations","authors":"Zhijun Tu, Shu Wang, Xiaodian Chen and Jifeng Liu","doi":"10.3847/1538-4357/adaf9f","DOIUrl":"https://doi.org/10.3847/1538-4357/adaf9f","url":null,"abstract":"We report the spectroscopic identification of three brown dwarf candidates—o005_s41280, o006_s00089, and o006_s35616—discovered in RUBIES using James Webb Space Telescope (JWST) Near-Infrared Spectrograph PRISM/CLEAR spectroscopy. We fit these sources with multiple substellar atmosphere models and present the atmospheric parameters, including effective temperature (Teff), surface gravity, and other derived properties. The results suggest that o005_s41280 and o006_s35616, with Teff in the ranges of 2100–2300 K and 1800–2000 K, respectively, are likely L dwarfs, while o006_s00089, with Teff < 1000 K, is consistent with a late T dwarf classification. The best-fit model spectra provide a reasonable match to the observed spectra. However, distinct residuals exist in the Y, J, and H bands for the two L dwarf candidates, particularly for o006_s35616. Incorporating the extinction parameter into the fitting process can significantly reduce these residuals. The distance estimates indicate that these candidates are about 2 kpc away. The analysis of the color–color diagram using multiple JWST NIRcam photometry suggests that cooler T dwarfs, such as o006_s00089, overlap with little red dots, while hotter L dwarfs, like o005_s41280 and o006_s35616, tend to contaminate the high-redshift galaxy cluster. These findings suggest a brown dwarf contamination rate of approximately 0.1% in extragalactic deep field surveys, with L dwarfs being more frequently detected than cooler T and Y dwarfs.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443270","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adadf5
Emily Lichko, Damiano Caprioli, Benedikt Schroer and Siddhartha Gupta
A critical component of particle acceleration in astrophysical shocks is the nonresonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cell simulations to investigate the high-CR-current regime, where the typical assumptions underlying the Bell instability break down. Despite being more strongly driven, significantly less magnetic field amplification is observed than in low-current cases, an effect due to the anisotropic heating that occurs in this regime. We also find that electron-scale modes, despite being the fastest growing, mostly lead to moderate electron heating and do not affect the late evolution or saturation of the instability.
{"title":"Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density","authors":"Emily Lichko, Damiano Caprioli, Benedikt Schroer and Siddhartha Gupta","doi":"10.3847/1538-4357/adadf5","DOIUrl":"https://doi.org/10.3847/1538-4357/adadf5","url":null,"abstract":"A critical component of particle acceleration in astrophysical shocks is the nonresonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cell simulations to investigate the high-CR-current regime, where the typical assumptions underlying the Bell instability break down. Despite being more strongly driven, significantly less magnetic field amplification is observed than in low-current cases, an effect due to the anisotropic heating that occurs in this regime. We also find that electron-scale modes, despite being the fastest growing, mostly lead to moderate electron heating and do not affect the late evolution or saturation of the instability.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"88 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443236","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adae8b
Haifan Zhu and Wei Wang
We constrain the spin of the black hole candidate MAXI J1727-203 using Insight-HXMT data. Due to limited Insight-HXMT observations covering only part of the outburst, NICER data were used to analyze the full outburst’s state transitions; we identified two of three HXMT observations in the high soft state and applied the continuum-fitting method to measure the spin. Based on previous estimates and continuum spectral fittings, we explored the parameter space and found that the best-fitting values were (D, i, M) ≈ (6 kpc, 30°, 12 M⊙). We also tested the variation of these parameters using Monte Carlo simulations, sampling over 3000 sets within the parameter ranges 5.9 kpc < D < 7 kpc, 24° < i < 35°, and 10 M⊙ < M < 14 M⊙, yielding a spin measurement of (1σ). In addition, we analyzed NuSTAR data in the low hard state and found a good fit with the tbabs∗(diskbb+powerlaw) model, with no significant iron line features observed in the residuals; therefore, the previous reflection model results suggesting an extremely high spin overestimates the black hole spin.
{"title":"Estimating the Black Hole Spin for the X-Ray Binary MAXI J1727-203 Based on Insight-HXMT","authors":"Haifan Zhu and Wei Wang","doi":"10.3847/1538-4357/adae8b","DOIUrl":"https://doi.org/10.3847/1538-4357/adae8b","url":null,"abstract":"We constrain the spin of the black hole candidate MAXI J1727-203 using Insight-HXMT data. Due to limited Insight-HXMT observations covering only part of the outburst, NICER data were used to analyze the full outburst’s state transitions; we identified two of three HXMT observations in the high soft state and applied the continuum-fitting method to measure the spin. Based on previous estimates and continuum spectral fittings, we explored the parameter space and found that the best-fitting values were (D, i, M) ≈ (6 kpc, 30°, 12 M⊙). We also tested the variation of these parameters using Monte Carlo simulations, sampling over 3000 sets within the parameter ranges 5.9 kpc < D < 7 kpc, 24° < i < 35°, and 10 M⊙ < M < 14 M⊙, yielding a spin measurement of (1σ). In addition, we analyzed NuSTAR data in the low hard state and found a good fit with the tbabs∗(diskbb+powerlaw) model, with no significant iron line features observed in the residuals; therefore, the previous reflection model results suggesting an extremely high spin overestimates the black hole spin.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443259","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 study the nucleosynthesis in a core-collapse supernova (CCSN) model including newly calculated neutrino-induced reaction rates with both collective and Mikheyev–Smirnov–Wolfenstein neutrino flavor oscillations considered. We show that the measurement of a pair of 11B/10B and 138La/139La or 6Li/7Li and 138La/139La in presolar grains that are inferred to have originated from CCSNs could constrain the neutrino mass hierarchy. The new shell model and the model of quasiparticle random phase approximation in the estimate of three important neutrino-induced reactions, ν + 16O, ν + 20Ne, and ν + 138Ba, are applied in our reaction network. The new rates decrease the calculated 7Li/6Li ratio by a factor of 5 compared with the previous study. More interestingly, these new rates result in a clear separation of the isotopic ratio of 11B/10B between normal and inverted mass hierarchies in the O/Ne, O/C, and C/He layers, where 138La abundance depends strongly on the mass hierarchy. In these layers, the sensitivity of the calculated abundances of 10,11B and 6,7Li to the nuclear reaction uncertainties is also tiny. Therefore, we propose that the 11B/10B versus 138La/139La and 6Li/7Li versus 138La/139La in type X silicon carbide grains sampled material from C/He layer can be used as a new probe to constrain the neutrino mass hierarchy.
{"title":"Exploring the Neutrino Mass Hierarchy from Isotopic Ratios of Supernova Nucleosynthesis Products in Presolar Grains","authors":"Xingqun Yao, Toshitaka Kajino, Yudong Luo, Takehito Hayakawa, Toshio Suzuki, Heamin Ko, Myung-Ki Cheoun, Seiya Hayakawa, Hidetoshi Yamaguchi and Silvio Cherubini","doi":"10.3847/1538-4357/adaaf2","DOIUrl":"https://doi.org/10.3847/1538-4357/adaaf2","url":null,"abstract":"We study the nucleosynthesis in a core-collapse supernova (CCSN) model including newly calculated neutrino-induced reaction rates with both collective and Mikheyev–Smirnov–Wolfenstein neutrino flavor oscillations considered. We show that the measurement of a pair of 11B/10B and 138La/139La or 6Li/7Li and 138La/139La in presolar grains that are inferred to have originated from CCSNs could constrain the neutrino mass hierarchy. The new shell model and the model of quasiparticle random phase approximation in the estimate of three important neutrino-induced reactions, ν + 16O, ν + 20Ne, and ν + 138Ba, are applied in our reaction network. The new rates decrease the calculated 7Li/6Li ratio by a factor of 5 compared with the previous study. More interestingly, these new rates result in a clear separation of the isotopic ratio of 11B/10B between normal and inverted mass hierarchies in the O/Ne, O/C, and C/He layers, where 138La abundance depends strongly on the mass hierarchy. In these layers, the sensitivity of the calculated abundances of 10,11B and 6,7Li to the nuclear reaction uncertainties is also tiny. Therefore, we propose that the 11B/10B versus 138La/139La and 6Li/7Li versus 138La/139La in type X silicon carbide grains sampled material from C/He layer can be used as a new probe to constrain the neutrino mass hierarchy.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443231","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/ada93b
Lei Lei, 磊 雷, Yi-Ying Wang, 艺颖 王, Guan-Wen Yuan, 官文 袁, Tong-Lin Wang, 彤琳 王, Martin A. T. Groenewegen, Yi-Zhong Fan and 一中 范
The James Webb Space Telescope (JWST) has recently conducted observations of massive galaxies at high redshifts, revealing a notable anomaly in their star formation efficiency (SFE). Motivated by the recent identification of three ~106M⊙ dark star candidates, we investigate whether dark stars can be the origin of the SFE excess. It turns out that the excess can be reproduced by a group of dark stars with M ≳ 103M⊙, because of their domination in generating primary UV radiation in high-redshift galaxies. The genesis of these dark stars is attributed to the capture of weakly interacting massive particles within a mass range of tens of gigaelectronvolts to a few teraelectronvolts. However, if the top-heavy initial mass function of dark stars holds up to ~105M⊙, the relic black holes stemming from their collapse would be too abundant to be consistent with the current observations of massive compact halo objects. We thus suggest that just a small fraction of SFE excess may be contributed by the very massive dark stars, with the majority likely originating from other sources, such as the Population III stars, in view of their rather similar UV radiation efficiencies.
{"title":"Can Dark Stars Account for the Star Formation Efficiency Excess at Very High Redshifts?","authors":"Lei Lei, 磊 雷, Yi-Ying Wang, 艺颖 王, Guan-Wen Yuan, 官文 袁, Tong-Lin Wang, 彤琳 王, Martin A. T. Groenewegen, Yi-Zhong Fan and 一中 范","doi":"10.3847/1538-4357/ada93b","DOIUrl":"https://doi.org/10.3847/1538-4357/ada93b","url":null,"abstract":"The James Webb Space Telescope (JWST) has recently conducted observations of massive galaxies at high redshifts, revealing a notable anomaly in their star formation efficiency (SFE). Motivated by the recent identification of three ~106M⊙ dark star candidates, we investigate whether dark stars can be the origin of the SFE excess. It turns out that the excess can be reproduced by a group of dark stars with M ≳ 103M⊙, because of their domination in generating primary UV radiation in high-redshift galaxies. The genesis of these dark stars is attributed to the capture of weakly interacting massive particles within a mass range of tens of gigaelectronvolts to a few teraelectronvolts. However, if the top-heavy initial mass function of dark stars holds up to ~105M⊙, the relic black holes stemming from their collapse would be too abundant to be consistent with the current observations of massive compact halo objects. We thus suggest that just a small fraction of SFE excess may be contributed by the very massive dark stars, with the majority likely originating from other sources, such as the Population III stars, in view of their rather similar UV radiation efficiencies.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443230","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adabc4
Deepayan Banik
Tidal locking of planets to their host stars results in an atmospheric circulation with a hotspot fixed to the frame of reference of the planet. On the other hand, asynchronously rotating planets feature moving hotspots either lagging or leading the corresponding substellar point as it translates along the surface. We show that a planet falling in the latter category could mimic the circulation of tidally synchronous planets under the influence of time-varying instellation, possibly provided by pulsating or multiple star systems. This happens when the planet’s diurnal period is in resonance with the period of instellation variation, leading to a planet-frame-fixed hotspot. Slight differences in the above periods lead to east–west or west–east creeping hotspots with a period significantly longer than both. The rate of hotspot motion is given by the difference between the diurnal and instellation variation rates, similar to the lower envelope frequency of beat patterns formed by two superposed waves in linear wave theory. We call this phenomenon “beating.” A combination of the radiative, rotational, wave propagation, and drag timescales establishes dynamical constraints on beating. Based on this, we classify a set of Kepler and TESS circumbinary planets with two candidates exhibiting climatic departures from the no-variation scenario. In general, hotter and faster-spinning planets are more susceptible to climatic departures. Beating, if it occurs, may additionally create optimistic extensions of habitable zones for corresponding systems.
{"title":"Planetary Rhythms: Synchronous Circulation on Variably Irradiated Asynchronous Planets","authors":"Deepayan Banik","doi":"10.3847/1538-4357/adabc4","DOIUrl":"https://doi.org/10.3847/1538-4357/adabc4","url":null,"abstract":"Tidal locking of planets to their host stars results in an atmospheric circulation with a hotspot fixed to the frame of reference of the planet. On the other hand, asynchronously rotating planets feature moving hotspots either lagging or leading the corresponding substellar point as it translates along the surface. We show that a planet falling in the latter category could mimic the circulation of tidally synchronous planets under the influence of time-varying instellation, possibly provided by pulsating or multiple star systems. This happens when the planet’s diurnal period is in resonance with the period of instellation variation, leading to a planet-frame-fixed hotspot. Slight differences in the above periods lead to east–west or west–east creeping hotspots with a period significantly longer than both. The rate of hotspot motion is given by the difference between the diurnal and instellation variation rates, similar to the lower envelope frequency of beat patterns formed by two superposed waves in linear wave theory. We call this phenomenon “beating.” A combination of the radiative, rotational, wave propagation, and drag timescales establishes dynamical constraints on beating. Based on this, we classify a set of Kepler and TESS circumbinary planets with two candidates exhibiting climatic departures from the no-variation scenario. In general, hotter and faster-spinning planets are more susceptible to climatic departures. Beating, if it occurs, may additionally create optimistic extensions of habitable zones for corresponding systems.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443232","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adafa8
Jack T. Dinsmore, Roger W. Romani, Nikos Mandarakas, Dmitry Blinov and Ioannis Liodakis
The Guitar nebula surrounding PSR B2224+65 boasts a pulsar X-ray filament likely aligned with the local magnetic field. We present new RoboPol stellar polarization data distributed along the line of sight to the pulsar. The polarizing effect of intervening magnetized dust allows us to extract a model for the dust-weighted magnetic field. We detect a magnetic field angle consistent with the filament if the pulsar is located in the more distant zone of its parallax-estimated distance range.
{"title":"The Guitar Filament’s Magnetic Field Revealed by Starlight Polarization","authors":"Jack T. Dinsmore, Roger W. Romani, Nikos Mandarakas, Dmitry Blinov and Ioannis Liodakis","doi":"10.3847/1538-4357/adafa8","DOIUrl":"https://doi.org/10.3847/1538-4357/adafa8","url":null,"abstract":"The Guitar nebula surrounding PSR B2224+65 boasts a pulsar X-ray filament likely aligned with the local magnetic field. We present new RoboPol stellar polarization data distributed along the line of sight to the pulsar. The polarizing effect of intervening magnetized dust allows us to extract a model for the dust-weighted magnetic field. We detect a magnetic field angle consistent with the filament if the pulsar is located in the more distant zone of its parallax-estimated distance range.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443294","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/ada7f9
Kevin Alabarta, Mariano Méndez, Federico García, Diego Altamirano, Yuexin Zhang, Liang Zhang, David M. Russell and Ole König
We use the rms and lag spectra of the type-C quasiperiodic oscillation (QPO) to study the properties of the Comptonization region (aka corona) during the low/hard and hard-intermediate states of the main outburst and reflare of MAXI J1348−630. We simultaneously fit the time-averaged energy spectrum of the source and the fractional rms and phase-lag spectra of the QPO with the time-dependent Comptonization model VKOMPTH. The data can be explained by two physically connected coronae interacting with the accretion disk via a feedback loop of X-ray photons. The best-fitting model consists of a corona of ∼103 km located at the inner edge of the disk and a second corona of ∼104 km horizontally extended and covering the inner parts of the accretion disk. The properties of both coronae during the reflare are similar to those during the low/hard state of the main outburst, reinforcing the idea that both the outburst and the reflare are driven by the same physical mechanisms. We combine our results for the type-C QPO with those from previous work focused on the study of type-A and type-B QPOs with the same model to study the evolution of the geometry of the corona through the whole outburst, including the reflare of MAXI J1348−630. Finally, we show that the sudden increase in the phase-lag frequency spectrum and the sharp drop in the coherence function previously observed in MAXI J1348−630 are due to the type-C QPO during the decay of the outburst and can be explained in terms of the geometry of the coronae.
{"title":"Geometry of the Comptonization Region of MAXI J1348−630 through Type-C Quasiperiodic Oscillations with NICER","authors":"Kevin Alabarta, Mariano Méndez, Federico García, Diego Altamirano, Yuexin Zhang, Liang Zhang, David M. Russell and Ole König","doi":"10.3847/1538-4357/ada7f9","DOIUrl":"https://doi.org/10.3847/1538-4357/ada7f9","url":null,"abstract":"We use the rms and lag spectra of the type-C quasiperiodic oscillation (QPO) to study the properties of the Comptonization region (aka corona) during the low/hard and hard-intermediate states of the main outburst and reflare of MAXI J1348−630. We simultaneously fit the time-averaged energy spectrum of the source and the fractional rms and phase-lag spectra of the QPO with the time-dependent Comptonization model VKOMPTH. The data can be explained by two physically connected coronae interacting with the accretion disk via a feedback loop of X-ray photons. The best-fitting model consists of a corona of ∼103 km located at the inner edge of the disk and a second corona of ∼104 km horizontally extended and covering the inner parts of the accretion disk. The properties of both coronae during the reflare are similar to those during the low/hard state of the main outburst, reinforcing the idea that both the outburst and the reflare are driven by the same physical mechanisms. We combine our results for the type-C QPO with those from previous work focused on the study of type-A and type-B QPOs with the same model to study the evolution of the geometry of the corona through the whole outburst, including the reflare of MAXI J1348−630. Finally, we show that the sudden increase in the phase-lag frequency spectrum and the sharp drop in the coherence function previously observed in MAXI J1348−630 are due to the type-C QPO during the decay of the outburst and can be explained in terms of the geometry of the coronae.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143451660","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}
Pub Date : 2025-02-19DOI: 10.3847/1538-4357/adae84
Valentin Thoss and Andreas Burkert
If primordial black holes (PBHs) of asteroidal mass make up the entire dark matter, they could be detectable through their gravitational influence in the solar system. In this work, we study the perturbations that PBHs induce on the orbits of planets. Detailed numerical simulations of the solar system, embedded in a halo of PBHs, are performed. We find that the gravitational effect of the PBHs is dominated by the closest encounter. Using the Earth–Mars distance as an observational probe, we show that the perturbations are smaller than the current measurement uncertainties and thus PBHs are not directly constrained by solar system ephemerides. We estimate that an improvement in the ranging accuracy by an order of magnitude or the extraction of signals well below the noise level is required to detect the gravitational influence of PBHs in the solar system in the foreseeable future.
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