The Astrophysical Journal Letters最新文献_第10页

Episodic X-Ray Outflows from the Tidal Disruption Event ASASSN-14li 来自潮汐扰动事件 ASASSN-14li 的偶发 X 射线外流

The Astrophysical Journal Letters Pub Date : 2025-02-28 DOI: 10.3847/2041-8213/adae03

Yukta Ajay, Dheeraj R. Pasham, Thomas Wevers, Eric R. Coughlin, Francesco Tombesi, Muryel Guolo and James F. Steiner

{"title":"Episodic X-Ray Outflows from the Tidal Disruption Event ASASSN-14li","authors":"Yukta Ajay, Dheeraj R. Pasham, Thomas Wevers, Eric R. Coughlin, Francesco Tombesi, Muryel Guolo and James F. Steiner","doi":"10.3847/2041-8213/adae03","DOIUrl":"https://doi.org/10.3847/2041-8213/adae03","url":null,"abstract":"ASASSN-14li is a low-redshift (z= 0.0206) tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum and has provided one of the most sensitive measurements of a TDE to date. Its X-ray spectrum is soft and thermal (kT ∼ 0.05 keV) and shows a residual broad absorption feature between 0.6 and 0.8 keV, which can be associated with a blueshifted O vii line (rest-frame energy 0.57 keV) resulting from an ultrafast outflow at early times (within 40 days of optical discovery). By carefully accounting for photon pileup and using XSTAR photoionization models tailored to the evolving disk continuum properties, we analyze the entire archival X-ray data from XMM-Newton and track the evolution of this absorption feature for ∼4.5 yr post-disruption. Our main finding is that the absorption feature is transient and intermittent. Assuming the same underlying physical model (i.e., outflows) for the recurring absorption feature in ASASSN-14li, the outflow is seen to disappear and reappear multiple times during the first ∼1.5 yr of its evolution. No observable spectral imprint is detected thereafter. While theoretical studies suggest the launch of outflows in the early phases of the outburst during the super-Eddington regime, the outflow’s intermittent behavior for multiple years after disruption is unusual. We discuss this peculiar behavior within the context of varying inner-disk truncation, radiation pressure, and magnetically driven outflow scenarios.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526000","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

Near- and Mid-ultraviolet Observations of X-6.3 Flare on 2024 February 22 Recorded by the Solar Ultraviolet Imaging Telescope on board Aditya-L1

The Astrophysical Journal Letters Pub Date : 2025-02-28 DOI: 10.3847/2041-8213/adb0be

Soumya Roy, Durgesh Tripathi, Sreejith Padinhatteeri, A. N. Ramaprakash, Abhilash R. Sarwade, Nived V. N., Janmejoy Sarkar, Rahul Gopalakrishnan, Rushikesh Deogaonkar, K. Sankarasubramanian, Sami K. Solanki, Dibyendu Nandy and Dipankar Banerjee

{"title":"Near- and Mid-ultraviolet Observations of X-6.3 Flare on 2024 February 22 Recorded by the Solar Ultraviolet Imaging Telescope on board Aditya-L1","authors":"Soumya Roy, Durgesh Tripathi, Sreejith Padinhatteeri, A. N. Ramaprakash, Abhilash R. Sarwade, Nived V. N., Janmejoy Sarkar, Rahul Gopalakrishnan, Rushikesh Deogaonkar, K. Sankarasubramanian, Sami K. Solanki, Dibyendu Nandy and Dipankar Banerjee","doi":"10.3847/2041-8213/adb0be","DOIUrl":"https://doi.org/10.3847/2041-8213/adb0be","url":null,"abstract":"Solar flares are regularly observed in extreme-ultraviolet soft X-rays (SXRs) and hard X-rays (HXRs). However, those in near- and mid-ultraviolet are sparse. The Solar Ultraviolet Imaging Telescope (SUIT) on board the Aditya-L1, launched on 2023 September 2, provides regular observations in the 200–400 nm wavelength range through 11 filters. Here, we report the observation of the X6.3 flare on 2024 February 22 using eight narrowband (NB) filters of SUIT. We have also used co-spatiotemporal observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), Solar Orbiter/STIX, GONG Hα, Aditya-L1/SoLEXS, and GOES. We obtained light curves over the flaring region from AIA 1600 and 1700 Å and GONG Hα and compared them with the disk-integrated light curve obtained from GOES and SoLEXS SXRs and STIX HXRs. We find that the flare peaks in SUIT NB01, NB03, NB04, and NB08 filters simultaneously with HXRs 1600 and 1700 Å, along with the peak temperature obtained from SoLEXS. In contrast, in NB02 and NB05, the flare peaks ∼2 min later than the HXR peak, while in NB06 and NB07, the flare peaks ∼3 min after the GOES SXR peak. To the best of our knowledge, this is the first observation of a flare in these wavelengths (except in NB03, NB04, and NB05). Moreover, for the first time, we show the presence of a bright kernel in NB02. These results demonstrate the capabilities of SUIT observations in flare studies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"116 9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518034","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-frequency Power Spectrum of Active Galactic Nucleus NGC 4051 Revealed by NICER

The Astrophysical Journal Letters Pub Date : 2025-02-27 DOI: 10.3847/2041-8213/adace8

B. Rani, Jungeun Kim, I. Papadakis, K. C. Gendreau, M. Masterson, K. Hamaguchi, E. Kara, S.-S. Lee and R. Mushotzky

{"title":"High-frequency Power Spectrum of Active Galactic Nucleus NGC 4051 Revealed by NICER","authors":"B. Rani, Jungeun Kim, I. Papadakis, K. C. Gendreau, M. Masterson, K. Hamaguchi, E. Kara, S.-S. Lee and R. Mushotzky","doi":"10.3847/2041-8213/adace8","DOIUrl":"https://doi.org/10.3847/2041-8213/adace8","url":null,"abstract":"Variability studies offer a compelling glimpse into black hole dynamics, and Neutron Star Interior Composition Explorer's (NICER’s) remarkable temporal resolution propels us even further. NICER observations of an active galactic nucleus (AGN), NGC 4051, have charted the geometry of the emission region of the central supermassive black hole. Our investigation of X-ray variability in NGC 4051 has detected extreme variations spanning a factor of 40–50 over a mere 10–12 hr. For the first time, we have constrained the X-ray power spectral density (PSD) of the source to 0.1 Hz, corresponding to a temporal frequency of 104 Hz in a galactic X-ray binary with a mass of 10 M⊙. No extra high-frequency break/bend or any quasiperiodic oscillations are found. Through detailed analysis of energy-dependent PSDs, we found that the PSD normalization, the high-frequency PSD slope, as well as the bending frequency remain consistent across all energies within the 0.3–3 keV band, revealing the presence of a constant temperature corona. These significant findings impose critical constraints on current models of X-ray emission and variability in AGN.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518098","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

Using Detailed Single-star and Binary-evolution Models to Probe the Large Observed Luminosity Spread of Red Supergiants in Young Open Star Clusters

The Astrophysical Journal Letters Pub Date : 2025-02-27 DOI: 10.3847/2041-8213/adb61a

Chen Wang, Lee Patrick, Abel Schootemeijer, Selma E. de Mink, Norbert Langer, Nikolay Britavskiy, Xiao-Tian Xu, Julia Bodensteiner, Eva Laplace, Ruggero Valli, Alejandro Vigna-Gómez, Jakub Klencki, Stephen Justham, Cole Johnston and Jing-ze Ma

{"title":"Using Detailed Single-star and Binary-evolution Models to Probe the Large Observed Luminosity Spread of Red Supergiants in Young Open Star Clusters","authors":"Chen Wang, Lee Patrick, Abel Schootemeijer, Selma E. de Mink, Norbert Langer, Nikolay Britavskiy, Xiao-Tian Xu, Julia Bodensteiner, Eva Laplace, Ruggero Valli, Alejandro Vigna-Gómez, Jakub Klencki, Stephen Justham, Cole Johnston and Jing-ze Ma","doi":"10.3847/2041-8213/adb61a","DOIUrl":"https://doi.org/10.3847/2041-8213/adb61a","url":null,"abstract":"Red supergiants (RSGs) represent a late evolutionary stage of massive stars. Recent observations reveal that the observed luminosity range of RSGs in young open clusters is wider than expected from single-star evolution models. Binary evolution effects have been suggested as a possible explanation. Here, we analyze 3670 detailed binary-evolution models, as well as corresponding single-star models, to probe the contribution of binary mass transfer and binary mergers to the luminosity distribution of RSGs in star clusters with ages up to 100 Myr. We confirm that the expected luminosity range of RSGs in a coeval population can span a factor of 10, as a consequence of mergers between two main-sequence stars, which reproduces the observed RSG luminosity ranges in rich clusters well. While the luminosity increase as consequence of mass transfer is more limited, it may help to increase the number of overluminous RSGs. However, our results also demonstrate that binary effects alone are insufficient to account for the number of RSGs found with luminosities of up to 3 times those predicted by current single-star models. We discuss observational accuracy, rotational mixing, age spread, and intrinsic RSG variability as possible explanations. Further observations of RSGs in young open clusters, in particular studies of their intrinsic brightness variability, appear crucial for disentangling these effects.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518099","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

Is the Spin of the Black Hole in GX 339–4 Negative?

The Astrophysical Journal Letters Pub Date : 2025-02-27 DOI: 10.3847/2041-8213/adb62e

Andrzej A. Zdziarski, Srimanta Banerjee, Michał Szanecki, Ranjeev Misra and Gulab Dewangan

{"title":"Is the Spin of the Black Hole in GX 339–4 Negative?","authors":"Andrzej A. Zdziarski, Srimanta Banerjee, Michał Szanecki, Ranjeev Misra and Gulab Dewangan","doi":"10.3847/2041-8213/adb62e","DOIUrl":"https://doi.org/10.3847/2041-8213/adb62e","url":null,"abstract":"We have studied the accreting black hole binary GX 339–4 using two highly accurate broadband X-ray data sets in very soft spectral states from simultaneous NICER and NuSTAR observations. Joint fitting of both data sets with relativistic models of the disk and its Comptonization and reflection allows us to relatively accurately determine the black hole mass, spin, distance, and inclination. However, we find that the measured values strongly depend on the used disk model. With widely used Kerr disk models treating departures from local blackbody spectra using color corrections, we find relatively low black hole masses and strongly negative spins (i.e., retrograde accretion). Then, models employing radiative transfer calculations of the disk atmosphere predict moderately positive spins and high masses. When adding a warm corona above the disk (as proposed before for both active galactic nuclei and accreting binaries), we find that the spin is weakly constrained but consistent with zero. In all cases, the fitted inclination is low, ≈30°–34°. For the spin axis aligned with the binary axis, the mass function for this source implies large values of the mass, consistent only with those obtained with either disk-atmosphere models or the presence of a warm corona. We also test different disk models for an assumed set of mass, distance, and inclination. We find that different models yield values of the spin parameter differing by up to ∼0.3. Our results confirm previously found strong model dependencies of the measured black hole spin, now by comparing different disk models and for a low-mass X-ray binary.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518100","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

Electrodynamics and Dissipation in the Binary Magnetosphere of Premerger Neutron Stars

The Astrophysical Journal Letters Pub Date : 2025-02-27 DOI: 10.3847/2041-8213/adb5fd

Jens F. Mahlmann and Andrei M. Beloborodov

引用次数: 0

Impact-induced Vaporization during Accretion of Planetary Bodies

The Astrophysical Journal Letters Pub Date : 2025-02-26 DOI: 10.3847/2041-8213/adb30e

Adrien Saurety, Razvan Caracas and Sean N. Raymond

{"title":"Impact-induced Vaporization during Accretion of Planetary Bodies","authors":"Adrien Saurety, Razvan Caracas and Sean N. Raymond","doi":"10.3847/2041-8213/adb30e","DOIUrl":"https://doi.org/10.3847/2041-8213/adb30e","url":null,"abstract":"Giant impacts dominate the late stages of accretion of rocky planets. They contribute to the heating, melting, and sometimes vaporizing of the bodies involved in the impacts. Due to fractionation during melting and vaporization, planet-building impacts can significantly change the composition and geochemical signatures of rocky objects. Using first-principles molecular dynamics simulations, we analyze the shock behavior of complex realistic silicate systems, representative of both rocky bodies. We introduce a novel criterion for vapor formation that uses entropy calculations to determine the minimum impact velocity required to pass the threshold for vapor production. We derive impact velocity criteria for vapor formation—7.1 km s−1 for chondritic bodies—and show that this threshold is reached in 61% and 89% of impacts in dynamical simulations of the late stages of accretion with classical and annulus starting configuration (respectively) for analogs of Earth. These outcomes should be nuanced by factors such as the impact angle and the mass of the impacting bodies, which further influence the vaporization dynamics and the resultant material distribution. Our findings indicate that vaporization was common during accretion and likely played a crucial role in shaping the early environments and material properties of terrestrial planets.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506792","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

Radiative Cooling Changes the Dynamics of Magnetically Arrested Disks

The Astrophysical Journal Letters Pub Date : 2025-02-26 DOI: 10.3847/2041-8213/adb749

Akshay Singh, Damien Bégué and Asaf Pe’er

引用次数: 0

Kite-borne Spectroscopic Observations of the Corona During the 2023 April 20 Total Solar Eclipse

The Astrophysical Journal Letters Pub Date : 2025-02-26 DOI: 10.3847/2041-8213/adad53

Benedikt Justen, Shadia Rifai Habbal, Matthias Justen, Oliver Mayer, Adalbert Ding, Klemens Brumann and Herbert Stehr

{"title":"Kite-borne Spectroscopic Observations of the Corona During the 2023 April 20 Total Solar Eclipse","authors":"Benedikt Justen, Shadia Rifai Habbal, Matthias Justen, Oliver Mayer, Adalbert Ding, Klemens Brumann and Herbert Stehr","doi":"10.3847/2041-8213/adad53","DOIUrl":"https://doi.org/10.3847/2041-8213/adad53","url":null,"abstract":"We report in this Letter on the first use of a kite as an airborne platform for coronal observations during total solar eclipses, to mitigate the detrimental impact of clouds when present. In this first innovative attempt, the scientific payload was chosen to be a single-channel color spectrometer operating in high order over the wavelength range of 400–1000 nm, with light being fed from a coelostat that tracked the Sun optically. The payload was made airborne by a Cody-box-type kite with a wingspan of 6.5 m and launched from Cape Range National Park in North West Australia during the 2023 April 20 total solar eclipse. The kite and payload reached a terminal altitude of 450 m about 30 minutes prior to second contact and remained airborne 1 hr past the 58 s of totality. Although the tracking was not perfect, it nevertheless enabled the acquisition of two coronal spectra. This first successful technology demonstration paves the way for the feasibility of future low-cost kite-borne payloads for astronomical observations not limited to total solar eclipses.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143507092","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

Multimission Observations of Relativistic Electrons and High-speed Jets Linked to Shock-generated Transients

The Astrophysical Journal Letters Pub Date : 2025-02-25 DOI: 10.3847/2041-8213/adb154

Savvas Raptis, Martin Lindberg, Terry Z. Liu, Drew L. Turner, Ahmad Lalti, Yufei Zhou, Primož Kajdič, Athanasios Kouloumvakos, David G. Sibeck, Laura Vuorinen, Adam Michael, Mykhaylo Shumko, Adnane Osmane, Eva Krämer, Lucile Turc, Tomas Karlsson, Christos Katsavrias, Lynn B. Wilson, Hadi Madanian, Xóchitl Blanco-Cano, Ian J. Cohen and C. Philippe Escoubet

{"title":"Multimission Observations of Relativistic Electrons and High-speed Jets Linked to Shock-generated Transients","authors":"Savvas Raptis, Martin Lindberg, Terry Z. Liu, Drew L. Turner, Ahmad Lalti, Yufei Zhou, Primož Kajdič, Athanasios Kouloumvakos, David G. Sibeck, Laura Vuorinen, Adam Michael, Mykhaylo Shumko, Adnane Osmane, Eva Krämer, Lucile Turc, Tomas Karlsson, Christos Katsavrias, Lynn B. Wilson, Hadi Madanian, Xóchitl Blanco-Cano, Ian J. Cohen and C. Philippe Escoubet","doi":"10.3847/2041-8213/adb154","DOIUrl":"https://doi.org/10.3847/2041-8213/adb154","url":null,"abstract":"Shock-generated transients, such as hot flow anomalies (HFAs), upstream of planetary bow shocks, play a critical role in electron acceleration. Using multimission data from NASA’s Magnetospheric Multiscale and ESA’s Cluster missions, we demonstrate the transmission of HFAs through Earth’s quasi-parallel bow shock, accelerating electrons to relativistic energies in the process. Energetic electrons initially accelerated upstream are shown to remain broadly confined within the transmitted transient structures downstream, where they get further energized due to the elevated compression levels potentially by betatron acceleration. Additionally, high-speed jets form at the compressive edges of HFAs, exhibiting a significant increase in dynamic pressure and potentially contributing to further localized compression. Our findings emphasize the efficiency of quasi-parallel shocks in driving particle acceleration far beyond the immediate shock transition region, expanding the acceleration region to a larger spatial domain. Finally, this study underscores the importance of a multiscale observational approach in understanding the convoluted processes behind collisionless shock physics and their broader implications.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495176","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