The Astrophysical Journal Letters最新文献_第3页

Hints of New Physics for the Hubble Tension: Violation of Cosmological Principle 哈勃张力的新物理学提示：违反宇宙学原理

The Astrophysical Journal Letters Pub Date : 2024-11-04 DOI: 10.3847/2041-8213/ad85cf

J. P. Hu, X. D. Jia, J. Hu and F. Y. Wang

{"title":"Hints of New Physics for the Hubble Tension: Violation of Cosmological Principle","authors":"J. P. Hu, X. D. Jia, J. Hu and F. Y. Wang","doi":"10.3847/2041-8213/ad85cf","DOIUrl":"https://doi.org/10.3847/2041-8213/ad85cf","url":null,"abstract":"Discrepancy between the measurements of Hubble constant H0 from the cosmic microwave background and the local distance ladder is the most serious challenge to the standard ΛCDM model. Recent research has pointed out that it might be related with the violation of cosmological principle. Here, we investigate the impact of dipole–monopole correction on the constraints of H0 utilizing the dipole-fitting method based on the ΛCDM model and cosmography method. Our results show that the dipole–monopole correction can reduce the constraints of H0 from a larger value consistent with SH0ES results to a smaller value consistent with Planck results. This finding can effectively alleviate the Hubble tension. Through making redshift tomography and model-independent analyses, we confirm that our findings are independent of the redshift and cosmological model. In addition, the theoretical prediction of H(z)/(1 + z) reconstructed by the constraints of the ΛCDM model with the dipole correction is in agreement with baryon acoustic oscillation (BAO) measurements, including five Dark Energy Spectroscopic Instrument BAOs within the 1σ range except a data point at z = 0.51. Our research suggests that the Hubble tension originates from new physics beyond the standard ΛCDM model, which might lead to a violation of the cosmological principle.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579980","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

Probing the Low-velocity Regime of Nonradiative Shocks with Neutron Star Bow Shocks 用中子星弓形冲击探测非辐射冲击的低速区

The Astrophysical Journal Letters Pub Date : 2024-11-04 DOI: 10.3847/2041-8213/ad87cf

Stella Koch Ocker and Maren Cosens

{"title":"Probing the Low-velocity Regime of Nonradiative Shocks with Neutron Star Bow Shocks","authors":"Stella Koch Ocker and Maren Cosens","doi":"10.3847/2041-8213/ad87cf","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87cf","url":null,"abstract":"Nonradiative shocks accelerate particles and heat astrophysical plasmas. While supernova remnants are the most well-studied example, neutron star (NS) bow shocks are also nonradiative and Balmer dominated. NS bow shocks are likely ubiquitous in the interstellar medium due to their large speeds imparted at birth, and they are thought to be a discrete source population contributing to the Galactic cosmic-ray spectrum. To date, nine NS bow shocks have been directly observed in Hα images. Most of these shocks have been characterized using narrowband Hα imaging and slit spectroscopy, which do not resolve the multicomponent velocity structure of the shocks and their spatial geometry. Here we present integral field spectroscopy of three NS bow shocks: J0742−2822, J1741−2054, and J2225+6535 (the Guitar Nebula). We measure the shock properties simultaneously in four dimensions: the 2D projected shock morphology, the radial velocity structure, and the Hα flux. The broad-to-narrow line ratio (Ib/In) is inferred from radial velocity profiles, and for J1741−2054, the narrow line is detected in multiple regions of the shock. The inferred line ratios and widths suggest that NS bow shocks represent a low-shock velocity regime (V ≲ 200 km s−1) in which Ib/In is high, distinct from the shock regime probed by supernova remnants. Our results illustrate a need for nonradiative shock models at velocities lower than previously considered, which will reveal the electron–ion temperature ratios and particle acceleration efficiencies of these bow shocks.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580011","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

Effects of Dust Coagulation on Streaming Instability 粉尘凝结对流体不稳定性的影响

The Astrophysical Journal Letters Pub Date : 2024-11-04 DOI: 10.3847/2041-8213/ad8655

Ka Wai Ho, Hui Li and Shengtai Li

引用次数: 0

The Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light-curve Evolution and Color–Inclination Trends in Brown Dwarfs and Giant Exoplanets 极涡假说：不断演变、光谱截然不同的极区解释了褐矮星和巨型系外行星的短期和长期光曲线演变以及色倾角趋势

The Astrophysical Journal Letters Pub Date : 2024-11-04 DOI: 10.3847/2041-8213/ad87e9

Nguyen Fuda and Dániel Apai

{"title":"The Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light-curve Evolution and Color–Inclination Trends in Brown Dwarfs and Giant Exoplanets","authors":"Nguyen Fuda and Dániel Apai","doi":"10.3847/2041-8213/ad87e9","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87e9","url":null,"abstract":"Recent studies revealed viewing-angle-dependent color and spectral trends in brown dwarfs, as well as long-term photometric variability (∼100 hr). The origins of these trends are yet unexplained. Here, we propose that these seemingly unrelated sets of observations stem from the same phenomenon: the polar regions of brown dwarfs and directly imaged exoplanets are spectrally different from lower-latitude regions, and they evolve over longer timescales, possibly driven by polar vortices. We explore this hypothesis via a spatiotemporal atmosphere model capable of simulating time series and disk-integrated spectra of ultracool atmospheres. We study three scenarios with different spectral and temporal components: a null hypothesis without polar vortex, and two scenarios with polar vortices. We find that the scenarios with polar vortex can explain the observed infrared color–inclination trend and the variability amplitude–inclination trend. The presence of spectrally distinct, time-evolving polar regions in brown dwarfs and giant exoplanet atmospheres raises the possibility that one-dimensional static atmospheric models may be insufficient for reproducing ultracool atmospheres in detail.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580026","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

Direct Observations of a Shock Traversing Preceding Two Coronal Mass Ejections: Insights from Solar Orbiter, Wind, and STEREO Observations 直接观测两次日冕物质抛射前的冲击穿越：从太阳轨道器、风和 STEREO 观测中获得的启示

The Astrophysical Journal Letters Pub Date : 2024-11-01 DOI: 10.3847/2041-8213/ad87e8

Yutian Chi, Chenglong Shen, Zhiyong Zhang, Mengjiao Xu, Dongwei Mao, Junyan Liu, Can Wang, Bingkun Yu, Jingyu Luo, Zhihui Zhong and Yuming Wang

{"title":"Direct Observations of a Shock Traversing Preceding Two Coronal Mass Ejections: Insights from Solar Orbiter, Wind, and STEREO Observations","authors":"Yutian Chi, Chenglong Shen, Zhiyong Zhang, Mengjiao Xu, Dongwei Mao, Junyan Liu, Can Wang, Bingkun Yu, Jingyu Luo, Zhihui Zhong and Yuming Wang","doi":"10.3847/2041-8213/ad87e8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87e8","url":null,"abstract":"The three successive coronal mass ejections (CMEs) that erupted from 2023 November 27–28, provide the first opportunity to shed light on the entire process of a shock propagating through, sequentially compressing, and modifying two preceding CMEs using in situ data from Solar Orbiter, Wind, and STEREO-A. We describe the interaction of the three CMEs as follows: CME-1 and CME-2 interacted with each other at distances close to the Sun. Subsequently, the shock (S3) driven by CME-3 caught up with and compressed ICME-2 before 0.83 au, forming a typical shock–ICME interaction event observed by the Solar Orbiter. The S3 continued to propagate, crossing ICME-2 and propagating into ICME-1 as observed by Wind, and completely overtaking both ICME-1 and ICME-2 at STEREO-A. The interaction between S3 and the preceding two ICMEs leads to a clear compression of preceding ICMEs including an increase in magnetic field (∼150%) and a reduction in the interval of ICMEs. It presents direct and compelling evidence that a shock can completely traverse two preceding CMEs, accompanied by a significant decrease in shock strength (magnetic compression ratio decrease from 1.74 to 1.49). Even though the three ICMEs interact significantly in the heliosphere, their magnetic field configurations exhibit coherence at different observation points, especially for ICME-3. Those results highlight the significant implications of shock–CME interactions for CME propagation and space weather forecasting.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563089","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

First Detection of Molecular Gas in the Giant Low Surface Brightness Galaxy Malin 1 首次探测到低表面亮度巨型星系马林 1 中的分子气体

The Astrophysical Journal Letters Pub Date : 2024-11-01 DOI: 10.3847/2041-8213/ad8656

Gaspar Galaz, Jorge González-López, Viviana Guzmán, Hugo Messias, Junais, Samuel Boissier, Benoît Epinat, Peter M. Weilbacher, Thomas Puzia, Evelyn J. Johnston, Philippe Amram, David Frayer, Matìas Blaña, J. Christopher Howk, Michelle Berg, Roy Bustos-Espinoza, Juan Carlos Muñoz-Mateos, Paulo Cortés, Diego García-Appadoo and Katerine Joachimi

{"title":"First Detection of Molecular Gas in the Giant Low Surface Brightness Galaxy Malin 1","authors":"Gaspar Galaz, Jorge González-López, Viviana Guzmán, Hugo Messias, Junais, Samuel Boissier, Benoît Epinat, Peter M. Weilbacher, Thomas Puzia, Evelyn J. Johnston, Philippe Amram, David Frayer, Matìas Blaña, J. Christopher Howk, Michelle Berg, Roy Bustos-Espinoza, Juan Carlos Muñoz-Mateos, Paulo Cortés, Diego García-Appadoo and Katerine Joachimi","doi":"10.3847/2041-8213/ad8656","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8656","url":null,"abstract":"After over three decades of unsuccessful attempts, we report the first detection of molecular gas emission in Malin 1, the largest spiral galaxy observed to date, and one of the most iconic giant low surface brightness galaxies. Using Atacama Large Millimeter/submillimeter Array, we detect significant 12CO (J = 1–0) emission in the galaxy’s central region and tentatively identify CO emission across three regions on the disk. These observations allow for a better estimate of the H2 mass and molecular gas mass surface density, both of which are remarkably low given the galaxy’s scale. By integrating data on its H i mass, we derive a very low molecular-to-atomic gas mass ratio. Overall, our results highlight the minimal presence of molecular gas in Malin 1, contrasting sharply with its extensive, homogeneous atomic gas reservoir. For the first time, we position Malin 1 on the Kennicutt–Schmidt diagram, where it falls below the main sequence for normal spirals, consistent with previous upper limits but now with more accurate figures. These findings are crucial for constraining our understanding of star formation processes in environments characterized by extremely low molecular gas densities and for refining models of galaxy formation, thereby improving predictions concerning the formation, evolution, and distribution of these giant, elusive galaxies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563088","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

No Thick Atmosphere on the Terrestrial Exoplanet Gl 486b 地外行星Gl 486b上没有厚厚的大气层

The Astrophysical Journal Letters Pub Date : 2024-10-30 DOI: 10.3847/2041-8213/ad8161

Megan Weiner Mansfield, Qiao Xue, Michael Zhang, Alexandra S. Mahajan, Jegug Ih, Daniel Koll, Jacob L. Bean, Brandon Park Coy, Jason D. Eastman, Eliza M.-R. Kempton and Edwin S. Kite

{"title":"No Thick Atmosphere on the Terrestrial Exoplanet Gl 486b","authors":"Megan Weiner Mansfield, Qiao Xue, Michael Zhang, Alexandra S. Mahajan, Jegug Ih, Daniel Koll, Jacob L. Bean, Brandon Park Coy, Jason D. Eastman, Eliza M.-R. Kempton and Edwin S. Kite","doi":"10.3847/2041-8213/ad8161","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8161","url":null,"abstract":"A primary science goal for JWST is to detect and characterize the atmospheres of terrestrial planets orbiting M dwarfs (M-Earths). The existence of atmospheres on M-Earths is highly uncertain because their host stars’ extended history of high X-ray and ultraviolet irradiation may act to completely remove their atmospheres. We present two JWST secondary eclipse observations of the M-Earth Gl 486b (also known as GJ 486b) between 5 and 12 μm. We combined these observations with a precise analysis of the host star parameters to derive a planetary dayside temperature of Tp = 865 ± 14 K. We compared this temperature to the maximum expected temperature for a zero albedo, zero heat redistribution bare rock and derived a temperature ratio of . This value is consistent with an airless body with a slight nonzero albedo or a thin atmosphere with <1% H2O or <1 ppm CO2. However, it is inconsistent with an Earth- or Venus-like atmosphere, and the spectrum shows no clear emission or absorption features. Additionally, our observations are inconsistent with the water-rich atmospheric scenario allowed by previous transit observations and suggest the transmission spectrum was instead shaped by stellar contamination. Given the potential for atmospheric escape throughout the system’s ≥6.6 Gyr lifetime, we conclude that the observations are likely best explained by an airless planet. This result is the most precise measurement yet of terrestrial exoplanet thermal emission with JWST, which places a strong constraint on the position of the “cosmic shoreline” between airless bodies and those with atmospheres.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556276","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

The Large-scale Anisotropy and Flux (de)magnification of Ultrahigh-energy Cosmic Rays in the Galactic Magnetic Field 银河系磁场中超高能宇宙射线的大尺度各向异性和通量（去）放大率

The Astrophysical Journal Letters Pub Date : 2024-10-30 DOI: 10.3847/2041-8213/ad856f

Teresa Bister, Glennys R. Farrar and Michael Unger

引用次数: 0

Stripped Helium Star and Compact Object Binaries in Coeval Populations: Predictions Based on Detailed Binary Evolution Models 共生天体中的剥离氦星和紧凑天体双星：基于详细双星演化模型的预测

The Astrophysical Journal Letters Pub Date : 2024-10-30 DOI: 10.3847/2041-8213/ad86b7

Chen Wang, Julia Bodensteiner, Xiao-Tian Xu, Selma E. de Mink, Norbert Langer, Eva Laplace, Alejandro Vigna-Gómez, Stephen Justham, Jakub Klencki, Aleksandra Olejak, Ruggero Valli and Abel Schootemeijer

{"title":"Stripped Helium Star and Compact Object Binaries in Coeval Populations: Predictions Based on Detailed Binary Evolution Models","authors":"Chen Wang, Julia Bodensteiner, Xiao-Tian Xu, Selma E. de Mink, Norbert Langer, Eva Laplace, Alejandro Vigna-Gómez, Stephen Justham, Jakub Klencki, Aleksandra Olejak, Ruggero Valli and Abel Schootemeijer","doi":"10.3847/2041-8213/ad86b7","DOIUrl":"https://doi.org/10.3847/2041-8213/ad86b7","url":null,"abstract":"Massive stars mainly form in close binaries, where their mutual interactions can profoundly alter their evolutionary paths. Evolved binaries consisting of a massive OB-type main-sequence star with a stripped helium star or a compact companion represent a crucial stage in the evolution toward double compact objects, whose mergers are (potentially) detectable via gravitational waves. The recent detection of X-ray-quiet OB+black hole binaries and OB+stripped helium star binaries has set the stage for discovering more of these systems in the near future. In this work, based on 3670 detailed binary-evolution models and using empirical distributions of initial binary parameters, we compute the expected population of such evolved massive binaries in coeval stellar populations, including stars in star clusters and in galaxies with starburst activities, for ages up to 100 Myr. Our results are vividly illustrated in an animation that shows the evolution of these binaries in the color–magnitude diagram over time. We find that the number of OB+black hole binaries peaks around 10 Myr, and OB+neutron star binaries are most abundant at approximately 20 Myr. Both black holes and neutron stars can potentially be found in populations with ages up to 90 Myr. Additionally, we analyze the properties of such binaries at specific ages. We find that OB+helium stars and OB+black hole binaries are likely to be identifiable as single-lined spectroscopic binaries. Our research serves as a guide for future observational efforts to discover such binaries in young star clusters and starburst environments.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556278","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

Hints of a Sulfur-rich Atmosphere around the 1.6 R ⊕ Super-Earth L98-59 d from JWST NIRspec G395H Transmission Spectroscopy 从 JWST NIRspec G395H 透射光谱中发现的 1.6 R ⊕ 超级地球 L98-59 d 周围富硫大气层的端倪

The Astrophysical Journal Letters Pub Date : 2024-10-30 DOI: 10.3847/2041-8213/ad73d1

Amélie Gressier, Néstor Espinoza, Natalie H. Allen, David K. Sing, Agnibha Banerjee, Joanna K. Barstow, Jeff A. Valenti, Nikole K. Lewis, Stephan M. Birkmann, Ryan C. Challener, Elena Manjavacas, Catarina Alves de Oliveira, Nicolas Crouzet and Tracy. L Beck

{"title":"Hints of a Sulfur-rich Atmosphere around the 1.6 R ⊕ Super-Earth L98-59 d from JWST NIRspec G395H Transmission Spectroscopy","authors":"Amélie Gressier, Néstor Espinoza, Natalie H. Allen, David K. Sing, Agnibha Banerjee, Joanna K. Barstow, Jeff A. Valenti, Nikole K. Lewis, Stephan M. Birkmann, Ryan C. Challener, Elena Manjavacas, Catarina Alves de Oliveira, Nicolas Crouzet and Tracy. L Beck","doi":"10.3847/2041-8213/ad73d1","DOIUrl":"https://doi.org/10.3847/2041-8213/ad73d1","url":null,"abstract":"Detecting atmospheres around planets with a radius below 1.6 R⊕, commonly referred to as rocky planets, has proven to be challenging. However, rocky planets orbiting M dwarfs are ideal candidates due to their favorable planet-to-star radius ratio. Here, we present one transit observation of the Super-Earth L98-59 d (1.58 R⊕ and 2.31 M⊕), at the limit of rocky/gas-rich, using the JWST NIRSpec G395H mode covering the 2.8–5.1 μm wavelength range. The extracted transit spectrum from a single transit observation deviates from a flat line by 2.6σ–5.6σ, depending on the data reduction and retrieval setup. The hints of an atmospheric detection are driven by a large absorption feature between 3.3 and 4.8 μm. A stellar contamination retrieval analysis rejected the source of this feature as being due to stellar inhomogeneities, making the best fit an atmospheric model including sulfur-bearing species, suggesting that the atmosphere of L98-59 d may not be at equilibrium. This result will need to be confirmed by the analysis of the second NIRSpec G395H visit in addition to the NIRISS SOSS transit observation.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142541285","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