Pub Date : 2024-05-01DOI: 10.3847/2041-8213/ad4497
J. Morgenthaler, J. Rathbun, Carl A. Schmidt, Jeffrey Baumgardner, Nicholas M. Schneider
{"title":"Erratum: “Large Volcanic Event on Io Inferred from Jovian Sodium Nebula Brightening” (2019, ApJL, 871, L23)","authors":"J. Morgenthaler, J. Rathbun, Carl A. Schmidt, Jeffrey Baumgardner, Nicholas M. Schneider","doi":"10.3847/2041-8213/ad4497","DOIUrl":"https://doi.org/10.3847/2041-8213/ad4497","url":null,"abstract":"","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141048304","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 : 2024-02-20DOI: 10.3847/2041-8213/ad2617
W. Kurth
The two Voyager spacecraft have been exploring the interstellar medium beyond the heliopause since 2012 (Voyager 1) and 2018 (Voyager 2). Electron plasma oscillations and a quasi-thermal noise line at the electron plasma frequency have enabled the determination of the electron density in this region, revealing a radial density gradient convolved with shocks and pressure fronts. Voyager 1 has a functioning wideband receiver that provides high-spectral-resolution observations allowing the detection of the quasi-thermal noise line and has now provided electron densities to 161.4 au. Since a pressure pulse observed in 2020 around day 146 at about 149 au, the density has remained relatively constant at 0.147 cm−3 based on the most recent observations from 2023, suggesting that Voyager 1 has reached a broad density peak and possibly a new regime.
{"title":"Voyager 1 Electron Densities in the Very Local Interstellar Medium to beyond 160 au","authors":"W. Kurth","doi":"10.3847/2041-8213/ad2617","DOIUrl":"https://doi.org/10.3847/2041-8213/ad2617","url":null,"abstract":"\u0000 The two Voyager spacecraft have been exploring the interstellar medium beyond the heliopause since 2012 (Voyager 1) and 2018 (Voyager 2). Electron plasma oscillations and a quasi-thermal noise line at the electron plasma frequency have enabled the determination of the electron density in this region, revealing a radial density gradient convolved with shocks and pressure fronts. Voyager 1 has a functioning wideband receiver that provides high-spectral-resolution observations allowing the detection of the quasi-thermal noise line and has now provided electron densities to 161.4 au. Since a pressure pulse observed in 2020 around day 146 at about 149 au, the density has remained relatively constant at 0.147 cm−3 based on the most recent observations from 2023, suggesting that Voyager 1 has reached a broad density peak and possibly a new regime.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139958004","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 : 2024-02-01DOI: 10.3847/2041-8213/ad2465
Man Ho Chan, Chak Man Lee
Black hole dynamics suggests that dark matter would redistribute near a supermassive black hole (SMBH) to form a density spike. However, no direct evidence of a dark matter density spike around an SMBH has been identified. In this Letter, we present the first robust evidence showing a dark matter density spike around an SMBH. We revisit the data of the well-known SMBH binary OJ 287 and show that the inclusion of the dynamical friction due to a dark matter density spike around the SMBH can satisfactorily account for the observed orbital decay rate. The derived spike index γ sp = 2.351 − 0.045 + 0.032 gives an excellent agreement with the value γ sp = 2.333 predicted by the benchmark model assuming an adiabatically growing SMBH. This provides a strong verification of the canonical theory suggested two decades ago modeling the gravitational interaction between collisionless dark matter and SMBHs.
{"title":"The First Robust Evidence Showing a Dark Matter Density Spike Around the Supermassive Black Hole in OJ 287","authors":"Man Ho Chan, Chak Man Lee","doi":"10.3847/2041-8213/ad2465","DOIUrl":"https://doi.org/10.3847/2041-8213/ad2465","url":null,"abstract":"\u0000 Black hole dynamics suggests that dark matter would redistribute near a supermassive black hole (SMBH) to form a density spike. However, no direct evidence of a dark matter density spike around an SMBH has been identified. In this Letter, we present the first robust evidence showing a dark matter density spike around an SMBH. We revisit the data of the well-known SMBH binary OJ 287 and show that the inclusion of the dynamical friction due to a dark matter density spike around the SMBH can satisfactorily account for the observed orbital decay rate. The derived spike index \u0000 \u0000\u0000\u0000 \u0000 \u0000 \u0000 γ\u0000 \u0000 \u0000 sp\u0000 \u0000 \u0000 =\u0000 \u0000 \u0000 2.351\u0000 \u0000 \u0000 −\u0000 0.045\u0000 \u0000 \u0000 +\u0000 0.032\u0000 \u0000 \u0000 \u0000 \u0000 gives an excellent agreement with the value γ\u0000 sp = 2.333 predicted by the benchmark model assuming an adiabatically growing SMBH. This provides a strong verification of the canonical theory suggested two decades ago modeling the gravitational interaction between collisionless dark matter and SMBHs.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139966167","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}
Fan-spine magnetic structure, as a fundamental three-dimensional topology in magnetic reconnection theory, plays a crucial role in producing solar jets. However, how fan-spine configurations form in the solar atmosphere remains elusive. Using the Chinese Hα Solar Explorer (CHASE) and the Solar Dynamics Observatory, we present a case study on the complete buildup of fan-spine topology driven by flux emergence and the subsequent jet production. Two fan-spine structures and the two associated null points are present. Variations in null-point heights and locations were tracked over time during flux emergence. The north fan-spine structure is found to be created through magnetic reconnection between the newly emerged flux and the background field. Gentle reconnection persistently occurs after formation of the north fan-spine structure, resulting in weak plasma outflows. Subsequently, as flux emergence and magnetic helicity injection continue, the formation and eruption of minifilaments after reconnection at the quasi-separatrix layer between the two nulls trigger three homologous jets. The CHASE observations reveal that the circular flare ribbon, inner bright patch, and remote brightening all exhibit redshifted signatures during these jet ejections. This work unveils the key role of flux emergence in the formation of fan-spine topology, and highlights the importance of minifilaments for subsequent jet production.
{"title":"Formation of Fan-spine Magnetic Topology through Flux Emergence and Subsequent Jet Production","authors":"Yadan Duan, Hui Tian, Hechao Chen, Yuandeng Shen, Zheng Sun, Zhenyong Hou, Chuan Li","doi":"10.3847/2041-8213/ad24f3","DOIUrl":"https://doi.org/10.3847/2041-8213/ad24f3","url":null,"abstract":"\u0000 Fan-spine magnetic structure, as a fundamental three-dimensional topology in magnetic reconnection theory, plays a crucial role in producing solar jets. However, how fan-spine configurations form in the solar atmosphere remains elusive. Using the Chinese Hα Solar Explorer (CHASE) and the Solar Dynamics Observatory, we present a case study on the complete buildup of fan-spine topology driven by flux emergence and the subsequent jet production. Two fan-spine structures and the two associated null points are present. Variations in null-point heights and locations were tracked over time during flux emergence. The north fan-spine structure is found to be created through magnetic reconnection between the newly emerged flux and the background field. Gentle reconnection persistently occurs after formation of the north fan-spine structure, resulting in weak plasma outflows. Subsequently, as flux emergence and magnetic helicity injection continue, the formation and eruption of minifilaments after reconnection at the quasi-separatrix layer between the two nulls trigger three homologous jets. The CHASE observations reveal that the circular flare ribbon, inner bright patch, and remote brightening all exhibit redshifted signatures during these jet ejections. This work unveils the key role of flux emergence in the formation of fan-spine topology, and highlights the importance of minifilaments for subsequent jet production.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139965795","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 : 2024-01-01DOI: 10.3847/2041-8213/ad181a
Y. Jiménez-Teja, R. Dupke, P. Lopes, P. Dimauro
The intracluster light (ICL) fraction is a well-known indicator of the dynamical activity in intermediate-redshift clusters. Merging clusters in the redshift interval 0.18 < z < 0.56 have a distinctive peak in the ICL fractions measured between ∼3800 and 4800 Å . In this work, we analyze two higher-redshift, clearly merging clusters, ACT-CLJ0102-49151 and CL J0152.7-1357, at z > 0.8, using the Hubble Space Telescope optical and infrared images obtained by the RELICS survey. We report the presence of a similar peak in the ICL fractions, although wider and redshifted to the wavelength interval ∼5200–7300 Å. The fact that this excess in the ICL fractions is found at longer wavelengths can be explained by an assorted mixture of stellar populations in the ICL, direct inheritance of an ICL that was mainly formed by major galaxy mergers with the BCG at z > 1 and experienced an instantaneous burst due to the merging event. The ubiquity of the ICL fraction merging signature across cosmic time enhances the ICL as a highly reliable and powerful probe to determine the dynamical stage of galaxy clusters, which is crucial for cluster-based cosmological inferences that require relaxation of the sample.
星团内光（ICL）分数是中红移星团动态活动的一个众所周知的指标。红移区间为 0.18 < z < 0.56 的合并星团在 ∼3800 Å 和 4800 Å 之间测得的 ICL 分数有一个明显的峰值。在这项工作中，我们利用哈勃太空望远镜的光学和红外图像，分析了两个红移更高，明显合并的星团，ACT-CLJ0102-49151和CL J0152.7-1357，它们的z > 0.8。我们报告说，在ICL碎片中发现了一个类似的峰值，不过这个峰值更宽，并且红移到了5200-7300 Å波长区间。ICL碎片中的这种过量出现在更长的波长上，可以解释为ICL中恒星群的混杂，是ICL的直接继承，ICL主要是由z > 1时与BCG合并的大星系形成的，由于合并事件而经历了瞬间爆发。ICL部分合并特征在整个宇宙时间中无处不在，这增强了ICL作为确定星系团动力学阶段的一个高度可靠和强大的探测器的作用，这对于需要放宽样本的基于星系团的宇宙学推断是至关重要的。
{"title":"Evidence for a Redshifted Excess in the Intracluster Light Fractions of Merging Clusters at z ∼ 0.8","authors":"Y. Jiménez-Teja, R. Dupke, P. Lopes, P. Dimauro","doi":"10.3847/2041-8213/ad181a","DOIUrl":"https://doi.org/10.3847/2041-8213/ad181a","url":null,"abstract":"The intracluster light (ICL) fraction is a well-known indicator of the dynamical activity in intermediate-redshift clusters. Merging clusters in the redshift interval 0.18 < z < 0.56 have a distinctive peak in the ICL fractions measured between ∼3800 and 4800 Å . In this work, we analyze two higher-redshift, clearly merging clusters, ACT-CLJ0102-49151 and CL J0152.7-1357, at z > 0.8, using the Hubble Space Telescope optical and infrared images obtained by the RELICS survey. We report the presence of a similar peak in the ICL fractions, although wider and redshifted to the wavelength interval ∼5200–7300 Å. The fact that this excess in the ICL fractions is found at longer wavelengths can be explained by an assorted mixture of stellar populations in the ICL, direct inheritance of an ICL that was mainly formed by major galaxy mergers with the BCG at z > 1 and experienced an instantaneous burst due to the merging event. The ubiquity of the ICL fraction merging signature across cosmic time enhances the ICL as a highly reliable and powerful probe to determine the dynamical stage of galaxy clusters, which is crucial for cluster-based cosmological inferences that require relaxation of the sample.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139391720","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 : 2024-01-01DOI: 10.3847/2041-8213/ad0a95
T. S. Metcalfe, K. G. Strassmeier, Ilya Ilyin, D. Buzasi, O. Kochukhov, Thomas R. Ayres, S. Basu, A. Chontos, Adam J. Finley, Victor See, K. Stassun, J. V. van Saders, Aldo G. Sepulveda, G. Ricker
The consistently low activity level of the old solar analog 51 Peg not only facilitated the discovery of the first hot Jupiter, but also led to the suggestion that the star could be experiencing a magnetic grand minimum. However, the 50 yr time series showing minimal chromospheric variability could also be associated with the onset of weakened magnetic braking (WMB), where sufficiently slow rotation disrupts cycling activity and the production of large-scale magnetic fields by the stellar dynamo, thereby shrinking the Alfvén radius and inhibiting the efficient loss of angular momentum to magnetized stellar winds. In this Letter, we evaluate the magnetic evolutionary state of 51 Peg by estimating its wind braking torque. We use new spectropolarimetric measurements from the Large Binocular Telescope to reconstruct the large-scale magnetic morphology, we reanalyze archival X-ray measurements to estimate the mass-loss rate, and we detect solar-like oscillations in photometry from the Transiting Exoplanet Survey Satellite, yielding precise stellar properties from asteroseismology. Our estimate of the wind braking torque for 51 Peg clearly places it in the WMB regime, driven by changes in the mass-loss rate and the magnetic field strength and morphology that substantially exceed theoretical expectations. Although our revised stellar properties have minimal consequences for the characterization of the exoplanet, they have interesting implications for the current space weather environment of the system.
{"title":"Weakened Magnetic Braking in the Exoplanet Host Star 51 Peg","authors":"T. S. Metcalfe, K. G. Strassmeier, Ilya Ilyin, D. Buzasi, O. Kochukhov, Thomas R. Ayres, S. Basu, A. Chontos, Adam J. Finley, Victor See, K. Stassun, J. V. van Saders, Aldo G. Sepulveda, G. Ricker","doi":"10.3847/2041-8213/ad0a95","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0a95","url":null,"abstract":"The consistently low activity level of the old solar analog 51 Peg not only facilitated the discovery of the first hot Jupiter, but also led to the suggestion that the star could be experiencing a magnetic grand minimum. However, the 50 yr time series showing minimal chromospheric variability could also be associated with the onset of weakened magnetic braking (WMB), where sufficiently slow rotation disrupts cycling activity and the production of large-scale magnetic fields by the stellar dynamo, thereby shrinking the Alfvén radius and inhibiting the efficient loss of angular momentum to magnetized stellar winds. In this Letter, we evaluate the magnetic evolutionary state of 51 Peg by estimating its wind braking torque. We use new spectropolarimetric measurements from the Large Binocular Telescope to reconstruct the large-scale magnetic morphology, we reanalyze archival X-ray measurements to estimate the mass-loss rate, and we detect solar-like oscillations in photometry from the Transiting Exoplanet Survey Satellite, yielding precise stellar properties from asteroseismology. Our estimate of the wind braking torque for 51 Peg clearly places it in the WMB regime, driven by changes in the mass-loss rate and the magnetic field strength and morphology that substantially exceed theoretical expectations. Although our revised stellar properties have minimal consequences for the characterization of the exoplanet, they have interesting implications for the current space weather environment of the system.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393832","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 : 2024-01-01DOI: 10.3847/2041-8213/ad132d
F. La Monaca, A. Di Marco, J. Poutanen, M. Bachetti, S. Motta, A. Papitto, M. Pilia, F. Xie, Stefano Bianchi, Anna Bobrikova, E. Costa, Wei Deng, Ming-Yu Ge, Giulia Illiano, Shu-Mei Jia, H. Krawczynski, E. V. Lai, Kuan Liu, G. Mastroserio, F. Muleri, J. Rankin, P. Soffitta, A. Veledina, F. Ambrosino, M. Del Santo, Wei Chen, Javier A. García, P. Kaaret, T. Russell, Wen-Hao Wei, Shuang-Nan Zhang, Chao Zuo, Z. Arzoumanian, M. Cocchi, A. Gnarini, R. Farinelli, K. Gendreau, F. Ursini, M. Weisskopf, S. Zane, I. Agudo, L. Antonelli, L. Baldini, W. Baumgartner, R. Bellazzini, S. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, F. Capitanio, S. Castellano, E. Cavazzuti, Chien-Ting J. Chen, S. Ciprini, A. De Rosa, E. Del Monte, L. Di Gesu, N. Di Lalla, I. Donnarumma, V. Doroshenko, M. Dovc̆iak, S. Ehlert, T. Enoto, Y. Evangelista, S. Fabiani, R. Ferrazzoli, S. Gunji, K. Hayashida, J. Heyl, W. Iwakiri, S. Jorstad, V. Karas, F. Kislat, T. Kitaguchi, J. Kolodziejczak, L. Latronico, I. Liodakis, S. Maldera, A. Manfreda,
The Imaging X-ray Polarimetry Explorer measured with high significance the X-ray polarization of the brightest Z-source, Sco X-1, resulting in the nominal 2–8 keV energy band in a polarization degree of 1.0% ± 0.2% and a polarization angle of 8° ± 6° at a 90% confidence level. This observation was strictly simultaneous with observations performed by NICER, NuSTAR, and Insight-HXMT, which allowed for a precise characterization of its broadband spectrum from soft to hard X-rays. The source has been observed mainly in its soft state, with short periods of flaring. We also observed low-frequency quasiperiodic oscillations. From a spectropolarimetric analysis, we associate a polarization to the accretion disk at <3.2% at 90% confidence level, compatible with expectations for an electron scattering dominated optically thick atmosphere at the Sco X-1 inclination of ∼44°; for the higher-energy Comptonized component, we obtain a polarization of 1.3% ± 0.4%, in agreement with expectations for a slab of Thomson optical depth of ∼7 and an electron temperature of ∼3 keV. A polarization rotation with respect to previous observations by OSO-8 and PolarLight, and also with respect to the radio-jet position angle, is observed. This result may indicate a variation of the polarization with the source state that can be related to relativistic precession or a change in the corona geometry with the accretion flow.
成像 X 射线偏振探测仪对最亮 Z 光源 Sco X-1 的 X 射线偏振进行了高精度测量，结果是名义 2-8 keV 能段的偏振度为 1.0% ± 0.2%，偏振角为 8° ± 6°，置信度为 90%。这次观测是与 NICER、NuSTAR 和 Insight-HXMT 的观测严格同步进行的，从而可以精确描述其从软 X 射线到硬 X 射线的宽带光谱。我们主要是在其软状态下观测到该星源的，但也有短时间的耀斑。我们还观测到了低频准周期振荡。通过光谱极化分析，我们得出吸积盘的极化率为＜3.2%（置信度为90%），这与Sco X-1倾角∼44°时以电子散射为主的光学厚大气层的预期相一致；对于高能量的康普顿化成分，我们得到的极化率为1.3% ± 0.4%，这与汤姆逊光学深度∼7和电子温度∼3 keV的板坯的预期相一致。与之前 OSO-8 和 PolarLight 的观测结果相比，偏振发生了旋转，与射电喷流的位置角也发生了旋转。这一结果可能表明极化随源状态的变化而变化，这可能与相对论前向或日冕几何形状随吸积流的变化有关。
{"title":"Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1","authors":"F. La Monaca, A. Di Marco, J. Poutanen, M. Bachetti, S. Motta, A. Papitto, M. Pilia, F. Xie, Stefano Bianchi, Anna Bobrikova, E. Costa, Wei Deng, Ming-Yu Ge, Giulia Illiano, Shu-Mei Jia, H. Krawczynski, E. V. Lai, Kuan Liu, G. Mastroserio, F. Muleri, J. Rankin, P. Soffitta, A. Veledina, F. Ambrosino, M. Del Santo, Wei Chen, Javier A. García, P. Kaaret, T. Russell, Wen-Hao Wei, Shuang-Nan Zhang, Chao Zuo, Z. Arzoumanian, M. Cocchi, A. Gnarini, R. Farinelli, K. Gendreau, F. Ursini, M. Weisskopf, S. Zane, I. Agudo, L. Antonelli, L. Baldini, W. Baumgartner, R. Bellazzini, S. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, F. Capitanio, S. Castellano, E. Cavazzuti, Chien-Ting J. Chen, S. Ciprini, A. De Rosa, E. Del Monte, L. Di Gesu, N. Di Lalla, I. Donnarumma, V. Doroshenko, M. Dovc̆iak, S. Ehlert, T. Enoto, Y. Evangelista, S. Fabiani, R. Ferrazzoli, S. Gunji, K. Hayashida, J. Heyl, W. Iwakiri, S. Jorstad, V. Karas, F. Kislat, T. Kitaguchi, J. Kolodziejczak, L. Latronico, I. Liodakis, S. Maldera, A. Manfreda, ","doi":"10.3847/2041-8213/ad132d","DOIUrl":"https://doi.org/10.3847/2041-8213/ad132d","url":null,"abstract":"The Imaging X-ray Polarimetry Explorer measured with high significance the X-ray polarization of the brightest Z-source, Sco X-1, resulting in the nominal 2–8 keV energy band in a polarization degree of 1.0% ± 0.2% and a polarization angle of 8° ± 6° at a 90% confidence level. This observation was strictly simultaneous with observations performed by NICER, NuSTAR, and Insight-HXMT, which allowed for a precise characterization of its broadband spectrum from soft to hard X-rays. The source has been observed mainly in its soft state, with short periods of flaring. We also observed low-frequency quasiperiodic oscillations. From a spectropolarimetric analysis, we associate a polarization to the accretion disk at <3.2% at 90% confidence level, compatible with expectations for an electron scattering dominated optically thick atmosphere at the Sco X-1 inclination of ∼44°; for the higher-energy Comptonized component, we obtain a polarization of 1.3% ± 0.4%, in agreement with expectations for a slab of Thomson optical depth of ∼7 and an electron temperature of ∼3 keV. A polarization rotation with respect to previous observations by OSO-8 and PolarLight, and also with respect to the radio-jet position angle, is observed. This result may indicate a variation of the polarization with the source state that can be related to relativistic precession or a change in the corona geometry with the accretion flow.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139392938","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 : 2023-12-01DOI: 10.3847/2041-8213/ad1192
M. Stumpo, S. Benella, T. Alberti, O. Pezzi, E. Papini, G. Consolini
Turbulent energy transfer in nearly collisionless plasmas can be conceptualized as a scale-to-scale Langevin process. Hence, the statistics of magnetic field fluctuations can be embedded in the framework of stochastic process theory. In this work, we investigate the statistical properties of the pristine solar wind as observed by Parker Solar Probe by defining the cascade trajectories of magnetic field increments and by estimating the stochastic entropy variation along them. Through the stochastic entropy, we can identify two regimes where fluctuations exhibit contrasting statistical properties. In the inertial range, the entropy production is associated with an increase of the flatness indicating the occurrence of intermittency. Otherwise, trajectories associated with an entropy consumption exhibit global scale invariance. In the transition region toward ion scales, the phenomenology switches: entropy-consuming trajectories exhibit a sudden flatness increase, associated with the presence of small-scale intermittency, while entropy-producing trajectories display a nearly constant flatness. Results are interpreted in terms of physical processes consistent with an accumulation of energy at ion scales.
{"title":"Relating Intermittency and Inverse Cascade to Stochastic Entropy in Solar Wind Turbulence","authors":"M. Stumpo, S. Benella, T. Alberti, O. Pezzi, E. Papini, G. Consolini","doi":"10.3847/2041-8213/ad1192","DOIUrl":"https://doi.org/10.3847/2041-8213/ad1192","url":null,"abstract":"Turbulent energy transfer in nearly collisionless plasmas can be conceptualized as a scale-to-scale Langevin process. Hence, the statistics of magnetic field fluctuations can be embedded in the framework of stochastic process theory. In this work, we investigate the statistical properties of the pristine solar wind as observed by Parker Solar Probe by defining the cascade trajectories of magnetic field increments and by estimating the stochastic entropy variation along them. Through the stochastic entropy, we can identify two regimes where fluctuations exhibit contrasting statistical properties. In the inertial range, the entropy production is associated with an increase of the flatness indicating the occurrence of intermittency. Otherwise, trajectories associated with an entropy consumption exhibit global scale invariance. In the transition region toward ion scales, the phenomenology switches: entropy-consuming trajectories exhibit a sudden flatness increase, associated with the presence of small-scale intermittency, while entropy-producing trajectories display a nearly constant flatness. Results are interpreted in terms of physical processes consistent with an accumulation of energy at ion scales.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138992247","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 : 2023-12-01DOI: 10.3847/2041-8213/ad12a4
Jonathan Lin, Michael P. Fitzgerald, Yinzi Xin, Yoo Jung Kim, O. Guyon, Barnaby Norris, C. Betters, Sergio Leon-Saval, K. Ahn, V. Deo, J. Lozi, S. Vievard, Daniel M. Levinstein, S. Sallum, Nemanja Jovanovic
The direct imaging of an Earth-like exoplanet will require sub-nanometric wave-front control across large light-collecting apertures to reject host starlight and detect the faint planetary signal. Current adaptive optics systems, which use wave-front sensors that reimage the telescope pupil, face two challenges that prevent this level of control: non-common-path aberrations, caused by differences between the sensing and science arms of the instrument; and petaling modes: discontinuous phase aberrations caused by pupil fragmentation, especially relevant for the upcoming 30 m class telescopes. Such aberrations drastically impact the capabilities of high-contrast instruments. To address these issues, we can add a second-stage wave-front sensor to the science focal plane. One promising architecture uses the photonic lantern (PL): a waveguide that efficiently couples aberrated light into single-mode fibers (SMFs). In turn, SMF-confined light can be stably injected into high-resolution spectrographs, enabling direct exoplanet characterization and precision radial velocity measurements; simultaneously, the PL can be used for focal-plane wave-front sensing. We present a real-time experimental demonstration of the PL wave-front sensor on the Subaru/SCExAO testbed. Our system is stable out to around ±400 nm of low-order Zernike wave-front error and can correct petaling modes. When injecting ∼30 nm rms of low-order time-varying error, we achieve ∼10× rejection at 1 s timescales; further refinements to the control law and lantern fabrication process should make sub-nanometric wave-front control possible. In the future, novel sensors like the PL wave-front sensor may prove to be critical in resolving the wave-front control challenges posed by exoplanet direct imaging.
{"title":"Real-time Experimental Demonstrations of a Photonic Lantern Wave-front Sensor","authors":"Jonathan Lin, Michael P. Fitzgerald, Yinzi Xin, Yoo Jung Kim, O. Guyon, Barnaby Norris, C. Betters, Sergio Leon-Saval, K. Ahn, V. Deo, J. Lozi, S. Vievard, Daniel M. Levinstein, S. Sallum, Nemanja Jovanovic","doi":"10.3847/2041-8213/ad12a4","DOIUrl":"https://doi.org/10.3847/2041-8213/ad12a4","url":null,"abstract":"The direct imaging of an Earth-like exoplanet will require sub-nanometric wave-front control across large light-collecting apertures to reject host starlight and detect the faint planetary signal. Current adaptive optics systems, which use wave-front sensors that reimage the telescope pupil, face two challenges that prevent this level of control: non-common-path aberrations, caused by differences between the sensing and science arms of the instrument; and petaling modes: discontinuous phase aberrations caused by pupil fragmentation, especially relevant for the upcoming 30 m class telescopes. Such aberrations drastically impact the capabilities of high-contrast instruments. To address these issues, we can add a second-stage wave-front sensor to the science focal plane. One promising architecture uses the photonic lantern (PL): a waveguide that efficiently couples aberrated light into single-mode fibers (SMFs). In turn, SMF-confined light can be stably injected into high-resolution spectrographs, enabling direct exoplanet characterization and precision radial velocity measurements; simultaneously, the PL can be used for focal-plane wave-front sensing. We present a real-time experimental demonstration of the PL wave-front sensor on the Subaru/SCExAO testbed. Our system is stable out to around ±400 nm of low-order Zernike wave-front error and can correct petaling modes. When injecting ∼30 nm rms of low-order time-varying error, we achieve ∼10× rejection at 1 s timescales; further refinements to the control law and lantern fabrication process should make sub-nanometric wave-front control possible. In the future, novel sensors like the PL wave-front sensor may prove to be critical in resolving the wave-front control challenges posed by exoplanet direct imaging.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139021278","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 : 2023-12-01DOI: 10.3847/2041-8213/ad0b14
Allison Kirkpatrick, Guang Yang, Aurélien Le Bail, Gregory Troiani, Eric F. Bell, N. Cleri, D. Elbaz, S. Finkelstein, N. Hathi, M. Hirschmann, B. Holwerda, D. Kocevski, R. Lucas, J. McKinney, C. Papovich, P. Pérez-González, Alexander de la Vega, Micaela B. Bagley, E. Daddi, Mark Dickinson, H. Ferguson, A. Fontana, A. Grazian, N. Grogin, P. A. Haro, J. Kartaltepe, L. Kewley, A. Koekemoer, J. Lotz, L. Pentericci, N. Pirzkal, S. Ravindranath, R. Somerville, J. Trump, S. Wilkins, L. Yung
The Cosmic Evolution Early Release Science program observed the Extended Groth Strip (EGS) with the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) in 2022. In this paper, we discuss the four MIRI pointings that observed with longer-wavelength filters, including F770W, F1000W, F1280W, F1500W, F1800W, and F2100W. We compare the MIRI galaxies with the Spitzer/MIPS 24 μm population in the EGS field. We find that MIRI can observe an order of magnitude deeper than MIPS in significantly shorter integration times, attributable to JWST's much larger aperture and MIRI’s improved sensitivity. MIRI is exceptionally good at finding faint (L IR < 1010 L ⊙) galaxies at z ∼ 1–2. We find that a significant portion of MIRI galaxies are “mid-IR weak”—they have strong near-IR emission and relatively weaker mid-IR emission, and most of the star formation is unobscured. We present new IR templates that capture how the mid-to-near-IR emission changes with increasing infrared luminosity. We present two color–color diagrams to separate mid-IR weak galaxies and active galactic nuclei (AGN) from dusty star-forming galaxies and find that these color diagrams are most effective when used in conjunction with each other. We present the first number counts of 10 μm sources and find that there are ≲10 IR AGN per MIRI pointing, possibly due to the difficulty of distinguishing AGN from intrinsically mid-IR weak galaxies (due to low metallicities or dust content). We conclude that MIRI is most effective at observing moderate-luminosity (L IR = 109–1010 L ⊙) galaxies at z = 1–2, and that photometry alone is not effective at identifying AGN within this faint population.
{"title":"CEERS Key Paper. VII. JWST/MIRI Reveals a Faint Population of Galaxies at Cosmic Noon Unseen by Spitzer","authors":"Allison Kirkpatrick, Guang Yang, Aurélien Le Bail, Gregory Troiani, Eric F. Bell, N. Cleri, D. Elbaz, S. Finkelstein, N. Hathi, M. Hirschmann, B. Holwerda, D. Kocevski, R. Lucas, J. McKinney, C. Papovich, P. Pérez-González, Alexander de la Vega, Micaela B. Bagley, E. Daddi, Mark Dickinson, H. Ferguson, A. Fontana, A. Grazian, N. Grogin, P. A. Haro, J. Kartaltepe, L. Kewley, A. Koekemoer, J. Lotz, L. Pentericci, N. Pirzkal, S. Ravindranath, R. Somerville, J. Trump, S. Wilkins, L. Yung","doi":"10.3847/2041-8213/ad0b14","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0b14","url":null,"abstract":"The Cosmic Evolution Early Release Science program observed the Extended Groth Strip (EGS) with the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) in 2022. In this paper, we discuss the four MIRI pointings that observed with longer-wavelength filters, including F770W, F1000W, F1280W, F1500W, F1800W, and F2100W. We compare the MIRI galaxies with the Spitzer/MIPS 24 μm population in the EGS field. We find that MIRI can observe an order of magnitude deeper than MIPS in significantly shorter integration times, attributable to JWST's much larger aperture and MIRI’s improved sensitivity. MIRI is exceptionally good at finding faint (L IR < 1010 L ⊙) galaxies at z ∼ 1–2. We find that a significant portion of MIRI galaxies are “mid-IR weak”—they have strong near-IR emission and relatively weaker mid-IR emission, and most of the star formation is unobscured. We present new IR templates that capture how the mid-to-near-IR emission changes with increasing infrared luminosity. We present two color–color diagrams to separate mid-IR weak galaxies and active galactic nuclei (AGN) from dusty star-forming galaxies and find that these color diagrams are most effective when used in conjunction with each other. We present the first number counts of 10 μm sources and find that there are ≲10 IR AGN per MIRI pointing, possibly due to the difficulty of distinguishing AGN from intrinsically mid-IR weak galaxies (due to low metallicities or dust content). We conclude that MIRI is most effective at observing moderate-luminosity (L IR = 109–1010 L ⊙) galaxies at z = 1–2, and that photometry alone is not effective at identifying AGN within this faint population.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622420","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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