Pub Date : 2025-01-30DOI: 10.3847/2041-8213/ada894
R. Siebenmorgen, Frank Heymann and R. Chini
The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be corrected. However, as the grain size increases, the extinction properties become gray, meaning these particles contribute by a constant at wavelengths 1 μm, making them undetectable by photometry in the optical. In this study, we compare the parallactic and luminosity distances of a pristine sample of 33 well-known early-type stars with nonpeculiar reddening curves and find that the luminosity distance overestimates the parallactic distance in 80% of the cases. This discrepancy can be removed when incorporating a population of large, submicrometer-sized dust grains in a dust model that provides gray extinction, which diminishes the luminosity distance accordingly.
{"title":"Luminosity Distance and Extinction by Submicrometer-sized Grains","authors":"R. Siebenmorgen, Frank Heymann and R. Chini","doi":"10.3847/2041-8213/ada894","DOIUrl":"https://doi.org/10.3847/2041-8213/ada894","url":null,"abstract":"The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be corrected. However, as the grain size increases, the extinction properties become gray, meaning these particles contribute by a constant at wavelengths 1 μm, making them undetectable by photometry in the optical. In this study, we compare the parallactic and luminosity distances of a pristine sample of 33 well-known early-type stars with nonpeculiar reddening curves and find that the luminosity distance overestimates the parallactic distance in 80% of the cases. This discrepancy can be removed when incorporating a population of large, submicrometer-sized dust grains in a dust model that provides gray extinction, which diminishes the luminosity distance accordingly.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077595","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 : 2025-01-30DOI: 10.3847/2041-8213/adabc5
Masahiro N. Machida and Shantanu Basu
We perform a three-dimensional nonideal magnetohydrodynamic simulation of a strongly magnetized cloud core and investigate the complex structure caused by the interchange instability. This is the first simulation that does not use a central sink cell and calculates the long-term (>104 yr) evolution even as the disk and outflow formation occur. The magnetic field dissipates inside the disk, and magnetic flux accumulates around the edge of the disk, leading to the occurrence of interchange instability. During the main accretion phase, the interchange instability occurs recurrently, disturbing the circumstellar region and forming ring, arc, and cavity structures. These are consistent with recent high-resolution observations of circumstellar regions around young protostars. The structures extend to >1000 au and persist for at least 30,000 yr after protostar formation, demonstrating the dynamic removal process of magnetic flux during star formation. We find that the disk continues to grow even as interchange instability occurs, by accretion through channels between the outgoing cavities. The outflow is initially weak but becomes strong after ∼103 yr.
{"title":"Complex Structure around a Circumstellar Disk Caused by Interchange Instability","authors":"Masahiro N. Machida and Shantanu Basu","doi":"10.3847/2041-8213/adabc5","DOIUrl":"https://doi.org/10.3847/2041-8213/adabc5","url":null,"abstract":"We perform a three-dimensional nonideal magnetohydrodynamic simulation of a strongly magnetized cloud core and investigate the complex structure caused by the interchange instability. This is the first simulation that does not use a central sink cell and calculates the long-term (>104 yr) evolution even as the disk and outflow formation occur. The magnetic field dissipates inside the disk, and magnetic flux accumulates around the edge of the disk, leading to the occurrence of interchange instability. During the main accretion phase, the interchange instability occurs recurrently, disturbing the circumstellar region and forming ring, arc, and cavity structures. These are consistent with recent high-resolution observations of circumstellar regions around young protostars. The structures extend to >1000 au and persist for at least 30,000 yr after protostar formation, demonstrating the dynamic removal process of magnetic flux during star formation. We find that the disk continues to grow even as interchange instability occurs, by accretion through channels between the outgoing cavities. The outflow is initially weak but becomes strong after ∼103 yr.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077597","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 : 2025-01-30DOI: 10.3847/2041-8213/adaa7b
Xiao Cao, Yan-Mei Chen, Yong Shi, Junfeng Wang, Zhijie Zhou, Min Bao, Qiusheng Gu, Alexei Moiseev, Luis C. Ho, Lan Wang and Guangquan Zeng
Dual active galactic nuclei (AGNs) with comparable masses are commonly witnessed among the major merged galaxies with interaction remnants. Considering almost every massive galaxy is associated with multiple dwarf satellites around it, minor mergers involving galaxies with disproportional stellar masses should be much more common than major mergers, which would naturally lead to black hole (BH) pairs with significantly different masses. However, dual AGNs generated by minor mergers involving one or two dwarf galaxies are exceptionally rare and understudied. Moreover, good estimates of the masses of both BHs are not yet available to test this idea. Here we report the evidence of a dual AGN candidate with mass ratio ~7:1 located in an undisturbed disk galaxy. We identify the central BH with mass of 9.4 × 106M⊙ from its radio emission as well as AGN-driven galactic-scale biconical outflows. The off-centered BH generates obvious broad and narrow emission-line regions, which gives us a robust estimation of a 1.3 × 106M⊙ BH mass. We explore alternative scenarios for explaining the observational features of this system, including the complex gas kinematics triggered by central AGN activity and dust attenuation of the broad-line region of the central BH, finding that they failed to fully account for the kinematics of both the redshifted off-centered broad and narrow emission-line components.
{"title":"A Dual Active Black Hole Candidate with Mass Ratio ~7:1 in a Disk Galaxy","authors":"Xiao Cao, Yan-Mei Chen, Yong Shi, Junfeng Wang, Zhijie Zhou, Min Bao, Qiusheng Gu, Alexei Moiseev, Luis C. Ho, Lan Wang and Guangquan Zeng","doi":"10.3847/2041-8213/adaa7b","DOIUrl":"https://doi.org/10.3847/2041-8213/adaa7b","url":null,"abstract":"Dual active galactic nuclei (AGNs) with comparable masses are commonly witnessed among the major merged galaxies with interaction remnants. Considering almost every massive galaxy is associated with multiple dwarf satellites around it, minor mergers involving galaxies with disproportional stellar masses should be much more common than major mergers, which would naturally lead to black hole (BH) pairs with significantly different masses. However, dual AGNs generated by minor mergers involving one or two dwarf galaxies are exceptionally rare and understudied. Moreover, good estimates of the masses of both BHs are not yet available to test this idea. Here we report the evidence of a dual AGN candidate with mass ratio ~7:1 located in an undisturbed disk galaxy. We identify the central BH with mass of 9.4 × 106M⊙ from its radio emission as well as AGN-driven galactic-scale biconical outflows. The off-centered BH generates obvious broad and narrow emission-line regions, which gives us a robust estimation of a 1.3 × 106M⊙ BH mass. We explore alternative scenarios for explaining the observational features of this system, including the complex gas kinematics triggered by central AGN activity and dust attenuation of the broad-line region of the central BH, finding that they failed to fully account for the kinematics of both the redshifted off-centered broad and narrow emission-line components.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"123 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077594","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 : 2025-01-29DOI: 10.3847/2041-8213/ada958
Boris S. Kalita, Si-Yue Yu, John D. Silverman, Emanuele Daddi, Luis C. Ho, Andreas L. Faisst, Miroslava Dessauges-Zavadsky, Annagrazia Puglisi, Simon Birrer, Daichi Kashino, Xuheng Ding, Jeyhan S. Kartaltepe, Zhaoxuan Liu, Darshan Kakkad, Francesco Valentino, Olivier Ilbert, Georgios Magdis, Arianna S. Long, Shuowen Jin, Anton M. Koekemoer and Richard Massey
Recent JWST observations have revealed the prevalence of spiral structures at z > 1. Unlike in the local Universe, the origin and the consequence of spirals at this epoch remain unexplored. We use public JWST/NIRCam data from the COSMOS-Web survey to map spiral structures in eight massive (>1010.5M⊙) star-forming galaxies at zspec ∼ 1.5. We present a method for systematically quantifying spiral arms at z > 1, enabling direct measurements of flux distributions. Using rest-frame near-IR images, we construct morphological models accurately tracing spiral arms. We detect offsets (∼0.2–0.8 kpc) between the rest-frame optical and near-IR flux distributions across most arms. Drawing parallels to the local Universe, we conclude that these offsets reflect the presence of density waves. For 9 out of 18 arms, the offsets indicate spiral shocks triggered by density waves. In all, 5 arms have offsets in the opposite direction and are likely associated with tidal interactions. For the remaining cases with no detected offsets, we suggest that stochastic “clumpy” star formation is the primary driver of their formation. In conclusion, we find a multifaceted nature of spiral arms at z > 1, similar to that in the local Universe.
{"title":"A Multiwavelength Investigation of Spiral Structures in z > 1 Galaxies with JWST","authors":"Boris S. Kalita, Si-Yue Yu, John D. Silverman, Emanuele Daddi, Luis C. Ho, Andreas L. Faisst, Miroslava Dessauges-Zavadsky, Annagrazia Puglisi, Simon Birrer, Daichi Kashino, Xuheng Ding, Jeyhan S. Kartaltepe, Zhaoxuan Liu, Darshan Kakkad, Francesco Valentino, Olivier Ilbert, Georgios Magdis, Arianna S. Long, Shuowen Jin, Anton M. Koekemoer and Richard Massey","doi":"10.3847/2041-8213/ada958","DOIUrl":"https://doi.org/10.3847/2041-8213/ada958","url":null,"abstract":"Recent JWST observations have revealed the prevalence of spiral structures at z > 1. Unlike in the local Universe, the origin and the consequence of spirals at this epoch remain unexplored. We use public JWST/NIRCam data from the COSMOS-Web survey to map spiral structures in eight massive (>1010.5M⊙) star-forming galaxies at zspec ∼ 1.5. We present a method for systematically quantifying spiral arms at z > 1, enabling direct measurements of flux distributions. Using rest-frame near-IR images, we construct morphological models accurately tracing spiral arms. We detect offsets (∼0.2–0.8 kpc) between the rest-frame optical and near-IR flux distributions across most arms. Drawing parallels to the local Universe, we conclude that these offsets reflect the presence of density waves. For 9 out of 18 arms, the offsets indicate spiral shocks triggered by density waves. In all, 5 arms have offsets in the opposite direction and are likely associated with tidal interactions. For the remaining cases with no detected offsets, we suggest that stochastic “clumpy” star formation is the primary driver of their formation. In conclusion, we find a multifaceted nature of spiral arms at z > 1, similar to that in the local Universe.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077599","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 : 2025-01-29DOI: 10.3847/2041-8213/adaa7f
Q. Wu, F. Y. Wang, Z. Y. Zhao, P. Wang, H. Xu, Y. K. Zhang, D. J. Zhou, J. R. Niu, W. Y. Wang, S. X. Yi, Z. Q. Hua, S. B. Zhang, J. L. Han, W. W. Zhu, K. J. Lee, D. Li, X. F. Wu, Z. G. Dai and B. Zhang
Fast radio bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances with a mysterious origin. Observations show that at least some FRBs are produced by magnetars. All magnetar-powered FRB models require some triggering mechanisms, among which the most popular is the cracking of the crust of a neutron star, which is called a starquake. However, so far there has been no decisive evidence for this speculation. Here we report the energy functions of the three most active repeating FRBs, which show a universal break around 1038 erg. Such a break is similar to that of the frequency–magnitude relationship of earthquakes. The break, and the change in the power-law indices below and above it, can be well understood within the framework of FRBs triggered by starquakes in the magnetar models. The seed of weak FRBs can grow both on the magnetar surface and in the deeper crust. In contrast, the triggering of strong FRBs is confined by the crustal thickness, and the seed of strong FRBs can only grow on the surface. This difference in dimensionality causes a break in the scaling properties from weak to strong FRBs, occurring at a point where the penetration depth of starquakes equals the crustal thickness. Our result, together with the earthquake-like temporal properties of these FRBs, strongly supports the idea that FRBs are triggered by starquakes, providing a new opportunity to study the physical properties of the crust of a neutron star.
{"title":"A Universal Break in Energy Functions of Three Hyperactive Repeating Fast Radio Bursts","authors":"Q. Wu, F. Y. Wang, Z. Y. Zhao, P. Wang, H. Xu, Y. K. Zhang, D. J. Zhou, J. R. Niu, W. Y. Wang, S. X. Yi, Z. Q. Hua, S. B. Zhang, J. L. Han, W. W. Zhu, K. J. Lee, D. Li, X. F. Wu, Z. G. Dai and B. Zhang","doi":"10.3847/2041-8213/adaa7f","DOIUrl":"https://doi.org/10.3847/2041-8213/adaa7f","url":null,"abstract":"Fast radio bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances with a mysterious origin. Observations show that at least some FRBs are produced by magnetars. All magnetar-powered FRB models require some triggering mechanisms, among which the most popular is the cracking of the crust of a neutron star, which is called a starquake. However, so far there has been no decisive evidence for this speculation. Here we report the energy functions of the three most active repeating FRBs, which show a universal break around 1038 erg. Such a break is similar to that of the frequency–magnitude relationship of earthquakes. The break, and the change in the power-law indices below and above it, can be well understood within the framework of FRBs triggered by starquakes in the magnetar models. The seed of weak FRBs can grow both on the magnetar surface and in the deeper crust. In contrast, the triggering of strong FRBs is confined by the crustal thickness, and the seed of strong FRBs can only grow on the surface. This difference in dimensionality causes a break in the scaling properties from weak to strong FRBs, occurring at a point where the penetration depth of starquakes equals the crustal thickness. Our result, together with the earthquake-like temporal properties of these FRBs, strongly supports the idea that FRBs are triggered by starquakes, providing a new opportunity to study the physical properties of the crust of a neutron star.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077600","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 : 2025-01-29DOI: 10.3847/2041-8213/ada9e4
Xu Yang, Meiqi Wang, Andrew Cao, Kaifan Ji, Vasyl Yurchyshyn, Jiong Qiu, Sijie Yu, Jinhua Shen and Wenda Cao
We analyze high-resolution observations of an X-1.0 white-light flare, triggered by a filament eruption, on 2022 October 2. The full process of filament formation and subsequent eruption was captured in the Hα passband by the Visible Imaging Spectrograph (VIS) on board the Goode Solar Telescope (GST) within its center field of view. White-light emissions appear in flare ribbons following the filament eruption and Hα ribbon brightening. GST Broadband Filter Imager data show that the continuum intensity, as compared to the nearby quiet-Sun area, has increased by up to 20% in the photospheric TiO band around 7057 Å. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory reported 10% contrast enhancement in the continuum near Fe i 6173 Å line. The separation motion of two white-light kernels is recorded by the high-cadence GST/TiO images and is well accompanied by the motion of the VIS Hα flare ribbon leading edge. One kernel, located in a 150 Gauss field within a granulation area, exhibited an average apparent motion speed of 55 km s−1, which is the highest average speed ever reported. The other kernel drifted at 9 km s−1 in an 800 Gauss magnetic field area. Hard X-ray (HXR) emissions reaching up to 300 keV have been observed for this flare. The simultaneous occurrence of high-cadence HXR, microwave, and white-light emissions strongly suggests that the energetic particles from the flare directly contribute to the heating. The inverted HXR energy flux density corresponding to 10% TiO brightening is 2.07 ± 0.23 × 1011 erg cm−2 s−1 during the flare peak.
{"title":"High-resolution Observations of an X-1.0 White-light Flare with Moving Flare Ribbons","authors":"Xu Yang, Meiqi Wang, Andrew Cao, Kaifan Ji, Vasyl Yurchyshyn, Jiong Qiu, Sijie Yu, Jinhua Shen and Wenda Cao","doi":"10.3847/2041-8213/ada9e4","DOIUrl":"https://doi.org/10.3847/2041-8213/ada9e4","url":null,"abstract":"We analyze high-resolution observations of an X-1.0 white-light flare, triggered by a filament eruption, on 2022 October 2. The full process of filament formation and subsequent eruption was captured in the Hα passband by the Visible Imaging Spectrograph (VIS) on board the Goode Solar Telescope (GST) within its center field of view. White-light emissions appear in flare ribbons following the filament eruption and Hα ribbon brightening. GST Broadband Filter Imager data show that the continuum intensity, as compared to the nearby quiet-Sun area, has increased by up to 20% in the photospheric TiO band around 7057 Å. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory reported 10% contrast enhancement in the continuum near Fe i 6173 Å line. The separation motion of two white-light kernels is recorded by the high-cadence GST/TiO images and is well accompanied by the motion of the VIS Hα flare ribbon leading edge. One kernel, located in a 150 Gauss field within a granulation area, exhibited an average apparent motion speed of 55 km s−1, which is the highest average speed ever reported. The other kernel drifted at 9 km s−1 in an 800 Gauss magnetic field area. Hard X-ray (HXR) emissions reaching up to 300 keV have been observed for this flare. The simultaneous occurrence of high-cadence HXR, microwave, and white-light emissions strongly suggests that the energetic particles from the flare directly contribute to the heating. The inverted HXR energy flux density corresponding to 10% TiO brightening is 2.07 ± 0.23 × 1011 erg cm−2 s−1 during the flare peak.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077602","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 : 2025-01-29DOI: 10.3847/2041-8213/ada893
Haitang Li, Jinhan Guo, Xin Cheng, Chang Zhou, Xiaoli Yan, Jun Chen, Yang Guo, Jacob Oloketuyi, Mingde Ding and Yu Liu
Solar filaments are believed to be a clump of cold plasma accumulated in the magnetic dips. However, the magnetic configuration of filaments and the key factors for their formation remains elusive. In this Letter, we present a detailed study of the formation and eruption of a multifilament system with observations and simulations. Before the filament appeared visible, the chromospheric fibrils gradually gathered together, evolving from a diffuse distribution into threadlike structures that were nearly parallel to the polarity inversion lines. On 2022 March 20, an arch filament first appeared showing high dynamics, and subsequently two reserved S-shaped filaments were visibly observed. These two filament segments further reconnected, forming a long coherent filament and resulting in a double-decker configuration. In addition, continuous converging motion and magnetic flux cancellation were found in the photosphere during the evolution. Simultaneously, more bald patch structures appeared at the polarities' collision position. Through a data-driven numerical simulation, we further reconstructed the coronal magnetic field, which is composed of two twisted magnetic flux ropes (MFRs) with their bottom touching the photosphere, along with a group of sheared arcades forming an X-shaped configuration. These findings suggest that the magnetic configuration of the filament is in a highly dynamic state, evolving from a hybrid to a coherent MFR. Moreover, we propose that the formation and eruption of the multifilament system are closely related to magnetic reconnection taking place on the photosphere and in the lower corona, respectively, both mainly driven by the photospheric converging motion.
{"title":"The Formation of a Multifilament System Driven by Photospheric Converging Motions in a Bipolar Sunspot","authors":"Haitang Li, Jinhan Guo, Xin Cheng, Chang Zhou, Xiaoli Yan, Jun Chen, Yang Guo, Jacob Oloketuyi, Mingde Ding and Yu Liu","doi":"10.3847/2041-8213/ada893","DOIUrl":"https://doi.org/10.3847/2041-8213/ada893","url":null,"abstract":"Solar filaments are believed to be a clump of cold plasma accumulated in the magnetic dips. However, the magnetic configuration of filaments and the key factors for their formation remains elusive. In this Letter, we present a detailed study of the formation and eruption of a multifilament system with observations and simulations. Before the filament appeared visible, the chromospheric fibrils gradually gathered together, evolving from a diffuse distribution into threadlike structures that were nearly parallel to the polarity inversion lines. On 2022 March 20, an arch filament first appeared showing high dynamics, and subsequently two reserved S-shaped filaments were visibly observed. These two filament segments further reconnected, forming a long coherent filament and resulting in a double-decker configuration. In addition, continuous converging motion and magnetic flux cancellation were found in the photosphere during the evolution. Simultaneously, more bald patch structures appeared at the polarities' collision position. Through a data-driven numerical simulation, we further reconstructed the coronal magnetic field, which is composed of two twisted magnetic flux ropes (MFRs) with their bottom touching the photosphere, along with a group of sheared arcades forming an X-shaped configuration. These findings suggest that the magnetic configuration of the filament is in a highly dynamic state, evolving from a hybrid to a coherent MFR. Moreover, we propose that the formation and eruption of the multifilament system are closely related to magnetic reconnection taking place on the photosphere and in the lower corona, respectively, both mainly driven by the photospheric converging motion.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077598","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 : 2025-01-24DOI: 10.3847/2041-8213/ada554
Tsuyoshi Iizuka, Yuki Hibiya, Satoshi Yoshihara and Takehito Hayakawa
The radioactive decay of short-lived 26Al–26Mg has been used to estimate the timescales over which 26Al was produced in a nearby star and the protosolar disk evolved. The chronology commonly assumes that 26Al was uniformly distributed in the protosolar disk; however, this assumption is challenged by the discordance between the timescales defined by the Al–Mg and assumption-free Pb–Pb chronometers. We find that the 26Al heterogeneity is correlated with the nucleosynthetic stable Ti isotope variation, which can be ascribed to the nonuniform distribution of ejecta from a core-collapse supernova in the disk. We use the Al–Ti isotope correlation to calibrate variable 26Al abundances in Al–Mg dating of early solar system processes. The calibrated Al–Mg chronometer indicates a ≥1 Myr gap between parent body accretion ages of carbonaceous and noncarbonaceous chondrites. We further use the Al–Ti isotope correlation to constrain the timing and location of the supernova explosion, indicating that the explosion occurred at 20–30 pc from the protosolar cloud, 0.94 +0.25/–0.21 Myr before the formation of the oldest solar system solids. Our results imply that the Sun was born in association with a ∼25 Mʘ star.
{"title":"Timescales of Solar System Formation Based on Al–Ti Isotope Correlation by Supernova Ejecta","authors":"Tsuyoshi Iizuka, Yuki Hibiya, Satoshi Yoshihara and Takehito Hayakawa","doi":"10.3847/2041-8213/ada554","DOIUrl":"https://doi.org/10.3847/2041-8213/ada554","url":null,"abstract":"The radioactive decay of short-lived 26Al–26Mg has been used to estimate the timescales over which 26Al was produced in a nearby star and the protosolar disk evolved. The chronology commonly assumes that 26Al was uniformly distributed in the protosolar disk; however, this assumption is challenged by the discordance between the timescales defined by the Al–Mg and assumption-free Pb–Pb chronometers. We find that the 26Al heterogeneity is correlated with the nucleosynthetic stable Ti isotope variation, which can be ascribed to the nonuniform distribution of ejecta from a core-collapse supernova in the disk. We use the Al–Ti isotope correlation to calibrate variable 26Al abundances in Al–Mg dating of early solar system processes. The calibrated Al–Mg chronometer indicates a ≥1 Myr gap between parent body accretion ages of carbonaceous and noncarbonaceous chondrites. We further use the Al–Ti isotope correlation to constrain the timing and location of the supernova explosion, indicating that the explosion occurred at 20–30 pc from the protosolar cloud, 0.94 +0.25/–0.21 Myr before the formation of the oldest solar system solids. Our results imply that the Sun was born in association with a ∼25 Mʘ star.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027258","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}
The recent launch of Einstein Probe (EP) in early 2024 opened up a new window onto the transient X-ray sky, allowing for real-time discovery and follow-up of fast X-ray transients (FXRTs). Multiwavelength observations of FXRTs and their counterparts are key to characterize the properties of their outflows and, ultimately, identify their progenitors. Here, we report our long-term radio monitoring of EP 240315A, a long-lasting (∼1000 s) high-redshift (z = 4.9) FXRT associated to gamma-ray burst (GRB) 240315C. Our campaign, carried out with the Australian Telescope Compact Array, followed the transient’s evolution at two different frequencies (5.5 and 9 GHz) for 3 months. In the radio light curves we identify an unusual steep rise at 9 GHz, possibly due to a refreshed reverse shock, and a late-time rapid decay of the radio flux, which we interpret as a jet break due to the outflow collimation. We find that the multiwavelength counterpart of EP 240315A is well described by a model of relativistic jet seen close to its axis, with jet half-opening angle θj ≈ 3° and beaming-corrected total energy E ≃ 4 × 1051 erg, typical of GRBs. These results show that a substantial fraction of FXRTs may be associated to standard GRBs and that sensitive X-ray monitors, such as EP and the proposed HiZ-GUNDAM and Theseus missions, can successfully pinpoint their relativistic outflows up to high redshifts.
{"title":"Long-term Radio Monitoring of the Fast X-Ray Transient EP 240315a: Evidence for a Relativistic Jet","authors":"Roberto Ricci, Eleonora Troja, Yu-Han Yang, Muskan Yadav, Yuan Liu, Hui Sun, Xuefeng Wu, He Gao, Bing Zhang and Weimin Yuan","doi":"10.3847/2041-8213/ad8b3f","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8b3f","url":null,"abstract":"The recent launch of Einstein Probe (EP) in early 2024 opened up a new window onto the transient X-ray sky, allowing for real-time discovery and follow-up of fast X-ray transients (FXRTs). Multiwavelength observations of FXRTs and their counterparts are key to characterize the properties of their outflows and, ultimately, identify their progenitors. Here, we report our long-term radio monitoring of EP 240315A, a long-lasting (∼1000 s) high-redshift (z = 4.9) FXRT associated to gamma-ray burst (GRB) 240315C. Our campaign, carried out with the Australian Telescope Compact Array, followed the transient’s evolution at two different frequencies (5.5 and 9 GHz) for 3 months. In the radio light curves we identify an unusual steep rise at 9 GHz, possibly due to a refreshed reverse shock, and a late-time rapid decay of the radio flux, which we interpret as a jet break due to the outflow collimation. We find that the multiwavelength counterpart of EP 240315A is well described by a model of relativistic jet seen close to its axis, with jet half-opening angle θj ≈ 3° and beaming-corrected total energy E ≃ 4 × 1051 erg, typical of GRBs. These results show that a substantial fraction of FXRTs may be associated to standard GRBs and that sensitive X-ray monitors, such as EP and the proposed HiZ-GUNDAM and Theseus missions, can successfully pinpoint their relativistic outflows up to high redshifts.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020573","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 : 2025-01-22DOI: 10.3847/2041-8213/ad9ead
Samson H. W. Leong, Justin Janquart, Aditya Kumar Sharma, Paul Martens, Parameswaran Ajith and Otto A. Hannuksela
The dense and dynamic environments within active galactic nuclei (AGN) accretion disks may serve as prolific birthplaces for binary black holes (BBHs) and one possible origin for some of the BBHs detected by gravitational-wave (GW) observatories. We show that a considerable fraction of the BBH in AGN disks will be strongly lensed by the central supermassive black hole (SMBH). Thus, the nonobservation of lensed GW signals can be used to constrain the fraction of BBH binaries residing in AGN disks. The nondetection of lensing with current detections will be sufficient to start placing constraints on the fraction of BBHs living within accretion disks near the SMBH. In the next-generation detectors era, with BBH observations and no lensed events, we will be able to rule out most migration traps as dominant birthplaces of BBH mergers; moreover, we will be able to constrain the minimum size of the accretion disk. On the other hand, should AGNs constitute a major formation channel, lensed events from AGNs will become prominent in the future.
{"title":"Constraining Binary Mergers in Active Galactic Nuclei Disks Using the Nonobservation of Lensed Gravitational Waves","authors":"Samson H. W. Leong, Justin Janquart, Aditya Kumar Sharma, Paul Martens, Parameswaran Ajith and Otto A. Hannuksela","doi":"10.3847/2041-8213/ad9ead","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9ead","url":null,"abstract":"The dense and dynamic environments within active galactic nuclei (AGN) accretion disks may serve as prolific birthplaces for binary black holes (BBHs) and one possible origin for some of the BBHs detected by gravitational-wave (GW) observatories. We show that a considerable fraction of the BBH in AGN disks will be strongly lensed by the central supermassive black hole (SMBH). Thus, the nonobservation of lensed GW signals can be used to constrain the fraction of BBH binaries residing in AGN disks. The nondetection of lensing with current detections will be sufficient to start placing constraints on the fraction of BBHs living within accretion disks near the SMBH. In the next-generation detectors era, with BBH observations and no lensed events, we will be able to rule out most migration traps as dominant birthplaces of BBH mergers; moreover, we will be able to constrain the minimum size of the accretion disk. On the other hand, should AGNs constitute a major formation channel, lensed events from AGNs will become prominent in the future.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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