Abstract The equilibrium configuration of a solid strange star in the final inspiral phase with another compact object is generally discussed, and the starquake-related issue is revisited, for a special purpose to understand the precursor emission of binary compact star merger events (e.g., that of GRB211211A). As the binary system inspirals inward due to gravitational wave radiation, the ellipticity of the solid strangeon star increases due to the growing tidal field of its compact companion. Elastic energy is hence accumulated during the inspiral stage which might trigger a starquake before the merger when exceeds a critical value. The energy released during such starquakes is calculated and compared to the precursor observation of GRB211211A. The result shows that the energy might be insufficient for binary strangeon-star case unless the entire solid strangeon star shatters, and hence favors a black hole-strangeon star scenario for GRB211211A. The timescale of the precursor as well as the frequency of the observed quasi-periodic-oscillation have also been discussed in the starquake model.
{"title":"The precursor of GRB211211A: a tide-induced giant quake?","authors":"Enping Zhou, Yong Gao, Yurui Zhou, Xiaoyu Lai, Lijing Shao, Weiyang Wang, Shaolin Xiong, Renxin Xu, Shuxu Yi, Garvin Yim, Han Yue, Zhen Zhang","doi":"10.1088/1674-4527/ad0825","DOIUrl":"https://doi.org/10.1088/1674-4527/ad0825","url":null,"abstract":"Abstract The equilibrium configuration of a solid strange star in the final inspiral phase with another compact object is generally discussed, and the starquake-related issue is revisited, for a special purpose to understand the precursor emission of binary compact star merger events (e.g., that of GRB211211A). As the binary system inspirals inward due to gravitational wave radiation, the ellipticity of the solid strangeon star increases due to the growing tidal field of its compact companion. Elastic energy is hence accumulated during the inspiral stage which might trigger a starquake before the merger when exceeds a critical value. The energy released during such starquakes is calculated and compared to the precursor observation of GRB211211A. The result shows that the energy might be insufficient for binary strangeon-star case unless the entire solid strangeon star shatters, and hence favors a black hole-strangeon star scenario for GRB211211A. The timescale of the precursor as well as the frequency of the observed quasi-periodic-oscillation have also been discussed in the starquake model.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136104666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1088/1674-4527/ad07cd
Yan-Peng Chen, Ji-an Jiang, Wen-Tao Luo, Xianzhong Zheng, Min Fang, Chao Yang, Hong Yuan-Yu, Zong-Fei Lv
Abstract Aiming at improving the survey efficiency of the Wide Field Survey
Telescope (WFST), we have developed a basic scheduling strategy that takes into
account the telescope characteristics, observing conditions, and weather conditions
at the Lenghu site. The sky area is divided into rectangular regions, referred to as
‘tiles’, with a size of 2.577◦ × 2.634◦
slightly smaller than the focal area of the mosaic
CCDs. These tiles are continuously filled in annulars parallel to the equator. The
brightness of the sky background, which varies with the moon phase and distance
from the moon, plays a significant role in determining the accessible survey fields.
Approximately 50 connected tiles are grouped into one block for observation. To opti mize the survey schedule, we perform simulations by taking into account the length of
exposures, data readout, telescope slewing, and all relevant observing conditions. We
utilize the Greedy Algorithm for scheduling optimization. Additionally, we propose
a dedicated dithering pattern to cover the gaps between CCDs and the four corners
of the mosaic CCD array, which are located outside of the 3-degree field of view.
This dithering pattern helps to achieve relatively uniform exposure maps for the final
survey outputs.
{"title":"Basic Survey Scheduling for the Wide Field Survey Telescope (WFST)","authors":"Yan-Peng Chen, Ji-an Jiang, Wen-Tao Luo, Xianzhong Zheng, Min Fang, Chao Yang, Hong Yuan-Yu, Zong-Fei Lv","doi":"10.1088/1674-4527/ad07cd","DOIUrl":"https://doi.org/10.1088/1674-4527/ad07cd","url":null,"abstract":"Abstract Aiming at improving the survey efficiency of the Wide Field Survey
Telescope (WFST), we have developed a basic scheduling strategy that takes into
account the telescope characteristics, observing conditions, and weather conditions
at the Lenghu site. The sky area is divided into rectangular regions, referred to as
‘tiles’, with a size of 2.577◦ × 2.634◦
slightly smaller than the focal area of the mosaic
CCDs. These tiles are continuously filled in annulars parallel to the equator. The
brightness of the sky background, which varies with the moon phase and distance
from the moon, plays a significant role in determining the accessible survey fields.
Approximately 50 connected tiles are grouped into one block for observation. To opti mize the survey schedule, we perform simulations by taking into account the length of
exposures, data readout, telescope slewing, and all relevant observing conditions. We
utilize the Greedy Algorithm for scheduling optimization. Additionally, we propose
a dedicated dithering pattern to cover the gaps between CCDs and the four corners
of the mosaic CCD array, which are located outside of the 3-degree field of view.
This dithering pattern helps to achieve relatively uniform exposure maps for the final
survey outputs.
","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"10 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Long-term spectroscopic monitoring campaigns on active galactic nuclei (AGNs) provide a wealth of information about its interior structure and kinematics. However, a number of the observations suffer from the contamination of second-order spectra (SOS) which will introduce some undesirable uncertainties at red side of spectra. In this paper, we test the effect of SOS and propose a method to correct it in the time domain spectroscopic data using the simultaneously observed comparison stars. Based on the reverberation mapping (RM) data of NGC 5548 in 2019, one of the most intensively monitored AGNs by Lijiang 2.4-meter telescope, we find that scientific object, comparison star, and spectrophotometric standard star can jointly introduce up to ~30% SOS for Grism 14. This irregular but smooth SOS significantly affects the flux density and profile of emission line, while having little effect on the light curve. After applying our method to each spectrum, we find that the SOS can be corrected effectively. The deviation between corrected and intrinsic spectra is ~2%, and the impact of SOS on time lag is very minor. This method makes it possible to obtain the Hα RM measurements from archival data.
{"title":"Correcting the Contamination of Second-order Spectra: Improving Hα Measurements in Reverberation Mapping Campaigns","authors":"Wen-Zhe Xi, Kai-Xing Lu, Haicheng Feng, sha-sha li, Jinming Bai, Rui-Lei Zhou, Hongtao Liu, Jian-Guo Wang","doi":"10.1088/1674-4527/ad06f2","DOIUrl":"https://doi.org/10.1088/1674-4527/ad06f2","url":null,"abstract":"Abstract Long-term spectroscopic monitoring campaigns on active galactic nuclei (AGNs) provide a wealth of information about its interior structure and kinematics. However, a number of the observations suffer from the contamination of second-order spectra (SOS) which will introduce some undesirable uncertainties at red side of spectra. In this paper, we test the effect of SOS and propose a method to correct it in the time domain spectroscopic data using the simultaneously observed comparison stars. Based on the reverberation mapping (RM) data of NGC 5548 in 2019, one of the most intensively monitored AGNs by Lijiang 2.4-meter telescope, we find that scientific object, comparison star, and spectrophotometric standard star can jointly introduce up to ~30% SOS for Grism 14. This irregular but smooth SOS significantly affects the flux density and profile of emission line, while having little effect on the light curve. After applying our method to each spectrum, we find that the SOS can be corrected effectively. The deviation between corrected and intrinsic spectra is ~2%, and the impact of SOS on time lag is very minor. This method makes it possible to obtain the Hα RM measurements from archival data.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134973761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-25DOI: 10.1088/1674-4527/ad06f4
wu ruiqing, Chun-Hua Zhu, Lü Guoliang, Zhang Xiaojiao, Lu Xizhen, Yu Jinlong, Chen Wujin, Long Mengqiu
Abstract The polycyclic aromatic hydrocarbons (PAHs), PANHs, and peptoids dust
spectral calculations from the interstellar medium (ISM) is important for dust obser vations and theory. Our goal is to calculate the radiation spectrum of spherical PAHs
dust clusters in a vacuum containing ionized and applied in the presence of electric
field. And we propose a new simple computational model to calculate the size of three dimensional (3D) spherical dust clusters formed by different initial dust structures. By Vienna Ab−initio Simulation Package (VASP) code, the density functional theory (DFT) with the generalized approximation (GGA) was used to calculate the electron density gradient and obtain the radiation spectrum of dust. When the radius of spherical dust clusters is ∼ [0.009−0.042] µm, the dust radiation spectrum agrees well with the Z=0.02
mMMP stellar spectrums, and the PAHs radiation spectrum of NGC 4676 at wavelengths of (0-5] µm and (5-10] µm, respectively. In the ionized state, the N-PAH, C10H9N, 2(C4H4)1+, and peptoids 4(CHON), (C8H10N2O5)1+ dust clusters at 3.3 µm, while the 2(C22H21N3O2)1+, 4(CHON) dust clusters at 5.2 µm have obvious peaks. There is a characteristic of part of PAHs and peptoids clusters radiation at the near-infrared wavelength of 2 µm. However, especially after applying an electric field to the dust, the emission spectrum of the dust increase significantly in the radiation wavelength range [3-10]µm. Consequently, the dust clusters of PAHs, PANHs, and peptoids of the radius size ∼[0.009−0.042] µm are likely to exist in the ISM.
{"title":"Radiation Spectral Analysis of 3D Dust Molecular Clusters (PAHs) and Peptoids under Ionization and Electric Field in ISM","authors":"wu ruiqing, Chun-Hua Zhu, Lü Guoliang, Zhang Xiaojiao, Lu Xizhen, Yu Jinlong, Chen Wujin, Long Mengqiu","doi":"10.1088/1674-4527/ad06f4","DOIUrl":"https://doi.org/10.1088/1674-4527/ad06f4","url":null,"abstract":"Abstract The polycyclic aromatic hydrocarbons (PAHs), PANHs, and peptoids dust
spectral calculations from the interstellar medium (ISM) is important for dust obser vations and theory. Our goal is to calculate the radiation spectrum of spherical PAHs
dust clusters in a vacuum containing ionized and applied in the presence of electric
field. And we propose a new simple computational model to calculate the size of three dimensional (3D) spherical dust clusters formed by different initial dust structures. By Vienna Ab−initio Simulation Package (VASP) code, the density functional theory (DFT) with the generalized approximation (GGA) was used to calculate the electron density gradient and obtain the radiation spectrum of dust. When the radius of spherical dust clusters is ∼ [0.009−0.042] µm, the dust radiation spectrum agrees well with the Z=0.02
mMMP stellar spectrums, and the PAHs radiation spectrum of NGC 4676 at wavelengths of (0-5] µm and (5-10] µm, respectively. In the ionized state, the N-PAH, C10H9N, 2(C4H4)1+, and peptoids 4(CHON), (C8H10N2O5)1+ dust clusters at 3.3 µm, while the 2(C22H21N3O2)1+, 4(CHON) dust clusters at 5.2 µm have obvious peaks. There is a characteristic of part of PAHs and peptoids clusters radiation at the near-infrared wavelength of 2 µm. However, especially after applying an electric field to the dust, the emission spectrum of the dust increase significantly in the radiation wavelength range [3-10]µm. Consequently, the dust clusters of PAHs, PANHs, and peptoids of the radius size ∼[0.009−0.042] µm are likely to exist in the ISM.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"14 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135218362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-25DOI: 10.1088/1674-4527/ad06f3
Sai Yang, Youtian Niu, Zhe Wang, Xiukun Zhao, Bei Li, Yuling Ding, Gege Zhao, Anqi Zhang
Abstract Very low frequency (VLF) signals are propagated between the ground-ionosphere. Multimode interference will cause the phase to show oscillatory changes with distance while propagating at night, leading to abnormalities in the received VLF signal. This study uses the VLF signal received in Qingdao City, Shandong Province, from the Russian Alpha navigation system to explore the multimode interference problem of VLF signal propagation. The characteristics of the effect of multimode interference phenomena on the phase are analyzed according to the variation of the phase of the VLF signal. However, the phase of VLF signals will also be affected by the X-ray and energetic particles that are released during the eruption of solar flares, therefore the two phenomena are studied in this work. It is concluded that the X-ray will not affect the phase of VLF signals at night, but the energetic particles will affect the phase change, and the influence of energetic particles should be excluded in the study of multimode interference phenomena. Using VLF signals for navigation positioning in degraded or unavailable GPS conditions is of great practical significance for very low frequency navigation systems as it can avoid the influence of multimode interference and improve positioning accuracy.
{"title":"Observation and analysis of VLF nocturnal multimode interference phenomenon based on waveguide mode theory","authors":"Sai Yang, Youtian Niu, Zhe Wang, Xiukun Zhao, Bei Li, Yuling Ding, Gege Zhao, Anqi Zhang","doi":"10.1088/1674-4527/ad06f3","DOIUrl":"https://doi.org/10.1088/1674-4527/ad06f3","url":null,"abstract":"Abstract Very low frequency (VLF) signals are propagated between the ground-ionosphere. Multimode interference will cause the phase to show oscillatory changes with distance while propagating at night, leading to abnormalities in the received VLF signal. This study uses the VLF signal received in Qingdao City, Shandong Province, from the Russian Alpha navigation system to explore the multimode interference problem of VLF signal propagation. The characteristics of the effect of multimode interference phenomena on the phase are analyzed according to the variation of the phase of the VLF signal. However, the phase of VLF signals will also be affected by the X-ray and energetic particles that are released during the eruption of solar flares, therefore the two phenomena are studied in this work. It is concluded that the X-ray will not affect the phase of VLF signals at night, but the energetic particles will affect the phase change, and the influence of energetic particles should be excluded in the study of multimode interference phenomena. Using VLF signals for navigation positioning in degraded or unavailable GPS conditions is of great practical significance for very low frequency navigation systems as it can avoid the influence of multimode interference and improve positioning accuracy.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"IA-13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135216620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-24DOI: 10.1088/1674-4527/ad0689
Shihai Yang, Bo Xu, Xin Li
Abstract As the second Earth's Trojan asteroid, 2020 XL 5 is worthy of rendezvous and even sample return missions in many aspects. In this paper, a rendezvous mission to Earth's second Trojan asteroid 2020 XL 5 is proposed. However, due to its high inclination and large eccentricity, direct impulsive transfer requires large amounts of fuel consumption. To address this challenge, we explore the benefits of electric propulsion and multi-gravity assists techniques for interplanetary missions. These two techniques are integrated in this mission design. The design of low-thrust gravity-assists (LTGA) trajectory in multi-body dynamics is thoroughly investigated, which is a complex process. A comprehensive framework including three steps is presented here for optimization of LTGA trajectories in multi-body dynamics. The rendezvous mission to 2020 XL 5 is designed with this three-step approach. The most effective transfer sequence among the outcomes involves Earth-Venus-Earth-Venus-2020 XL 5 . Numerical results indicates that the combination of electric propulsion and multi-gravity assists can greatly reduce the fuel consumption, with fuel consumption of 9.03%, making it a highly favorable choice for this rendezvous mission.
{"title":"A Rendezvous Mission to the Second Earth Trojan Asteroid 2020 XL<sub>5</sub> with Low-Thrust Multi-Gravity Assists Techniques","authors":"Shihai Yang, Bo Xu, Xin Li","doi":"10.1088/1674-4527/ad0689","DOIUrl":"https://doi.org/10.1088/1674-4527/ad0689","url":null,"abstract":"Abstract As the second Earth's Trojan asteroid, 2020 XL 5 is worthy of rendezvous and even sample return missions in many aspects. In this paper, a rendezvous mission to Earth's second Trojan asteroid 2020 XL 5 is proposed. However, due to its high inclination and large eccentricity, direct impulsive transfer requires large amounts of fuel consumption. To address this challenge, we explore the benefits of electric propulsion and multi-gravity assists techniques for interplanetary missions. These two techniques are integrated in this mission design. The design of low-thrust gravity-assists (LTGA) trajectory in multi-body dynamics is thoroughly investigated, which is a complex process. A comprehensive framework including three steps is presented here for optimization of LTGA trajectories in multi-body dynamics. The rendezvous mission to 2020 XL 5 is designed with this three-step approach. The most effective transfer sequence among the outcomes involves Earth-Venus-Earth-Venus-2020 XL 5 . Numerical results indicates that the combination of electric propulsion and multi-gravity assists can greatly reduce the fuel consumption, with fuel consumption of 9.03%, making it a highly favorable choice for this rendezvous mission.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"9 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-23DOI: 10.1088/1674-4527/ad05e9
Han Wu, hailong zhang, Zhang Yazhou, Jie WANG, Xu Du, Ting ZHANG, Xinchen YE
Abstract The radio telescope possesses high sensitivity and strong signal collection capabilities. While receiving celestial radiation signals, it also captures Radio Frequency Interferences (RFI) introduced by human activities. RFI, as signals originating from sources other than the astronomical targets, significantly impacts the quality of astronomical data. This paper presents an RFI fast mitigation algorithm based on block Least Mean Square 
(LMS) algorithm. It enhances the traditional adaptive LMS filter by grouping L adjacent time sampled points into one block and applying the same filter coefficients for filtering within each block. This transformation reduces multiplication calculations and enhances algorithm efficiency by leveraging the time-domain convolution theorem. The algorithm is tested using baseband data from the Parkes 64-meter radio telescope’s pulsar observations and simulated data. The results confirm the algorithm’s effectiveness, as the pulsar profile after RFI mitigation closely matches the original pulsar profile.
{"title":"The RFI Fast Mitigation Algorithm Based on Block LMS Filter","authors":"Han Wu, hailong zhang, Zhang Yazhou, Jie WANG, Xu Du, Ting ZHANG, Xinchen YE","doi":"10.1088/1674-4527/ad05e9","DOIUrl":"https://doi.org/10.1088/1674-4527/ad05e9","url":null,"abstract":"Abstract The radio telescope possesses high sensitivity and strong signal collection capabilities. While receiving celestial radiation signals, it also captures Radio Frequency Interferences (RFI) introduced by human activities. RFI, as signals originating from sources other than the astronomical targets, significantly impacts the quality of astronomical data. This paper presents an RFI fast mitigation algorithm based on block Least Mean Square &#xD;(LMS) algorithm. It enhances the traditional adaptive LMS filter by grouping L adjacent time sampled points into one block and applying the same filter coefficients for filtering within each block. This transformation reduces multiplication calculations and enhances algorithm efficiency by leveraging the time-domain convolution theorem. The algorithm is tested using baseband data from the Parkes 64-meter radio telescope’s pulsar observations and simulated data. The results confirm the algorithm’s effectiveness, as the pulsar profile after RFI mitigation closely matches the original pulsar profile.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"R-29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135366516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-20DOI: 10.1088/1674-4527/ad057c
Ying Ru Lin, Cai-Juan Pan, Wei-Jian Lu
Abstract This paper explores the correlation between the fractional variation of the ionizing continuum and C IV BALs with different ionization levels. Our results reveal anti-correlations between fractional variation of the continuum and fractional EW variation of the C IV BALs without Al III BAL/mini-BALs at corresponding velocities, providing evidence for the widespread influence of the ionizing continuum variability on the variation of HiBALs. Conversely, for C IV BALs accompanied by Al III BAL/mini-BALs (LoBAL groups), no significant correction is detected. The absence of such a correlation does not rule out the possibility that variations in these low-ionization lines are caused by ionizing continuum variability, but rather suggests the influence of BAL saturation to some extent. This saturation effect is reflected in the distribution of the fractional EW variation, where the C IV BAL group accompanied by Al III BAL has smaller standard deviation for the best-fitting Gaussian component than the two BAL groups without Al III BAL. However, the distribution of fractional variation of their continuum does not show any significant difference. Besides the saturation influence, another potential explanation for the lack of correlations in the LoBAL groups may be the effects of other variability mechanisms besides the ionization change, such as clouds transiting across the line of sight.
摘要:本文探讨了不同电离水平下电离连续谱分数变化与c4bals的相关性。我们的研究结果揭示了在相应速度下，不含Al III BAL/mini-BAL的C IV BALs的连续统分数变化与电子束分数变化之间的反相关关系，为电离连续统变化对HiBALs变化的广泛影响提供了证据。相反，对于伴有Al III BAL/mini-BAL (global组)的C IV BAL，没有检测到明显的校正。这种相关性的缺失并不能排除这些低电离线的变化是由电离连续体变异引起的可能性，而是在某种程度上表明BAL饱和度的影响。这种饱和效应反映在分数EW变化的分布中，其中伴随Al III BAL的C IV BAL组的最佳拟合高斯分量的标准差小于不含Al III BAL的两个BAL组。然而，他们连续体的分数变异分布并没有表现出显著的差异。除了饱和影响之外，另一种可能的解释是global组中缺乏相关性可能是除电离变化之外的其他变异性机制的影响，例如云穿越视线。
{"title":"Relations between the fractional variation of the ionizing continuum and C IV broad absorption lines with different ionization levels","authors":"Ying Ru Lin, Cai-Juan Pan, Wei-Jian Lu","doi":"10.1088/1674-4527/ad057c","DOIUrl":"https://doi.org/10.1088/1674-4527/ad057c","url":null,"abstract":"Abstract This paper explores the correlation between the fractional variation of the ionizing continuum and C IV BALs with different ionization levels. Our results reveal anti-correlations between fractional variation of the continuum and fractional EW variation of the C IV BALs without Al III BAL/mini-BALs at corresponding velocities, providing evidence for the widespread influence of the ionizing continuum variability on the variation of HiBALs. Conversely, for C IV BALs accompanied by Al III BAL/mini-BALs (LoBAL groups), no significant correction is detected. The absence of such a correlation does not rule out the possibility that variations in these low-ionization lines are caused by ionizing continuum variability, but rather suggests the influence of BAL saturation to some extent. This saturation effect is reflected in the distribution of the fractional EW variation, where the C IV BAL group accompanied by Al III BAL has smaller standard deviation for the best-fitting Gaussian component than the two BAL groups without Al III BAL. However, the distribution of fractional variation of their continuum does not show any significant difference. Besides the saturation influence, another potential explanation for the lack of correlations in the LoBAL groups may be the effects of other variability mechanisms besides the ionization change, such as clouds transiting across the line of sight.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"32 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-20DOI: 10.1088/1674-4527/ad057d
Xiaoqi Wu, Cunying Xiao, Ali Esamdin, Jing Xu, Zewei Wang, Luo Xiao
Abstract Seeing is an important index to evaluate the quality of an astronomical site. To estimate seeing at Muztagh-ata site with height and time quantitatively, European Centre for Medium-Range Weather Forecasts Reanalysis database(ERA5) is used. Seeing calculated from ERA5 is compared consistently with the Differential Image Motion Monitor(DIMM) seeing at the height of 12 m. Results show that seeing decays exponentially with height at Muztagh-ata site. Seeing decays the fastest in autumn in 2021 and most slowly with height in summer. The seeing condition is better in autumn than in summer. The median value of seeing at 12 m is 0.89 arcsec, the maximum value is 1.21 arcsec in August and the minimum is 0.66 arcsec in October. The median value of seeing at 12 m is 0.72 arcsec in the nighttime and 1.08 arcsec in the daytime. Seeing is a combination of annual and about biannual variations with the same phase as temperature and wind speed indicating that seeing variation with time is influenced by temperature and wind speed. The Richardson number Ri is used to analyze the atmosphere stability and the variations of seeing are consistent with Ri between layers. These quantitative results would provide important reference for telescope observation strategy.
{"title":"Quantitative analysis of seeing with height and time at Muztagh-ata site based on ERA5 database","authors":"Xiaoqi Wu, Cunying Xiao, Ali Esamdin, Jing Xu, Zewei Wang, Luo Xiao","doi":"10.1088/1674-4527/ad057d","DOIUrl":"https://doi.org/10.1088/1674-4527/ad057d","url":null,"abstract":"Abstract Seeing is an important index to evaluate the quality of an astronomical site. To estimate seeing at Muztagh-ata site with height and time quantitatively, European Centre for Medium-Range Weather Forecasts Reanalysis database(ERA5) is used. Seeing calculated from ERA5 is compared consistently with the Differential Image Motion Monitor(DIMM) seeing at the height of 12 m. Results show that seeing decays exponentially with height at Muztagh-ata site. Seeing decays the fastest in autumn in 2021 and most slowly with height in summer. The seeing condition is better in autumn than in summer. The median value of seeing at 12 m is 0.89 arcsec, the maximum value is 1.21 arcsec in August and the minimum is 0.66 arcsec in October. The median value of seeing at 12 m is 0.72 arcsec in the nighttime and 1.08 arcsec in the daytime. Seeing is a combination of annual and about biannual variations with the same phase as temperature and wind speed indicating that seeing variation with time is influenced by temperature and wind speed. The Richardson number Ri is used to analyze the atmosphere stability and the variations of seeing are consistent with Ri between layers. These quantitative results would provide important reference for telescope observation strategy.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135568039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-20DOI: 10.1088/1674-4527/ad057b
Jiaqi Wang, Xiaojun Jiang, Jie Zheng, Hanna Kellermann, Arno Riffeser, Liang Wang, Karen A. Collins, Allyson Bieryla, Lars A Buchhave, Steve B Howell, Eric Girardin, Eric Jensen, Felipe Murgas, Mesut Yilmaz, Sam Quinn, Xing Gao, Ruo-Yu Zhou, Frank Grupp, Huijuan Wang
Abstract We report the confirmation of a sub-Saturn-size exoplanet, TOI-1194 b with a mass about 0.456 -0.051 +0.055 M J , and a very low mass companion star with a mass of about 96.47±1.5 M J , TOI-1251 B. Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite (TESS) are suitable for further follow-up observations by ground-based telescopes with small and medium apertures. The analysis is performed based on data from several telescopes worldwide, including telescopes in the Sino-German multi-band photometric campaign, which aimed at confirming TESS Objects of Interest (TOIs) using ground-based small-aperture and medium-aperture telescopes, especially for long-period targets. TOI-1194 b is confirmed based on the consistent periodic transits depths from the multiband photometric data. We measure an orbital period of 2.310644±0.000001d, and radius is 0.767 -0.041 +0.045 R J , and amplitude of RV curve is 69.36 -7.31 +7.90 m/s. TOI-1251 B is confirmed based on the multi-band photometric and high-resolution spectroscopic data, whose orbiting period is 5.963054 -0.000001 +0.000002 d, the radius is 0.947 -0.033 +0.035 R J , and amplitude of RV curve is 9848.87 -40.08 +41.86 m/s.
摘要:本文报道了凌日系外行星巡天卫星(TESS)提供的一颗质量约为0.456 -0.051 +0.055 M J的亚土星大小的系外行星TOI-1194 b和质量约为96.47±1.5 M J的极低质量伴星TOI-1251 b的确认，这些系外行星候选行星适合用中小型口径地面望远镜进行进一步的后续观测。该分析是基于来自世界各地多个望远镜的数据进行的，包括中德多波段光度测量运动中的望远镜，该运动旨在使用地基小孔径和中孔径望远镜确认TESS感兴趣的物体(toi)，特别是对长周期目标。TOI-1194 b是基于多波段光度数据中一致的周期凌日深度来确认的。我们测得其轨道周期为2.310644±0.000001d，半径为0.767 -0.041 +0.045 rj, RV曲线幅值为69.36 -7.31 +7.90 m/s。TOI-1251 B的轨道周期为5.963054 -0.000001 +0.000002 d，半径为0.947 -0.033 +0.035 R J, RV曲线幅值为9848.87 -40.08 +41.86 m/s。
{"title":"Confirmation of a Sub-Saturn-size transiting exoplanet orbiting a G dwarf: TOI-1194 b and a very low mass companion star:TOI-1251 B from TESS","authors":"Jiaqi Wang, Xiaojun Jiang, Jie Zheng, Hanna Kellermann, Arno Riffeser, Liang Wang, Karen A. Collins, Allyson Bieryla, Lars A Buchhave, Steve B Howell, Eric Girardin, Eric Jensen, Felipe Murgas, Mesut Yilmaz, Sam Quinn, Xing Gao, Ruo-Yu Zhou, Frank Grupp, Huijuan Wang","doi":"10.1088/1674-4527/ad057b","DOIUrl":"https://doi.org/10.1088/1674-4527/ad057b","url":null,"abstract":"Abstract We report the confirmation of a sub-Saturn-size exoplanet, TOI-1194 b with a mass about 0.456 -0.051 +0.055 M J , and a very low mass companion star with a mass of about 96.47±1.5 M J , TOI-1251 B. Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite (TESS) are suitable for further follow-up observations by ground-based telescopes with small and medium apertures. The analysis is performed based on data from several telescopes worldwide, including telescopes in the Sino-German multi-band photometric campaign, which aimed at confirming TESS Objects of Interest (TOIs) using ground-based small-aperture and medium-aperture telescopes, especially for long-period targets. TOI-1194 b is confirmed based on the consistent periodic transits depths from the multiband photometric data. We measure an orbital period of 2.310644±0.000001d, and radius is 0.767 -0.041 +0.045 R J , and amplitude of RV curve is 69.36 -7.31 +7.90 m/s. TOI-1251 B is confirmed based on the multi-band photometric and high-resolution spectroscopic data, whose orbiting period is 5.963054 -0.000001 +0.000002 d, the radius is 0.947 -0.033 +0.035 R J , and amplitude of RV curve is 9848.87 -40.08 +41.86 m/s.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"36 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135568041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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