Pub Date : 2024-05-29DOI: 10.3847/1538-4365/ad3f1c
Yong Zhao, Zibo Liu, Dongdong Ni and Zhiyuan Chen
In previous work, we demonstrated that machine-learning techniques based on mixture density networks (MDNs) are successful in inferring the interior structure of rocky exoplanets with large compositional diversity. In this study, we compare the performance of a well-trained MDN model with the conventional Bayesian inversion method based on the Markov chain Monte Carlo (MCMC) method, under the same observable constraints. Considering that MCMC inversion is generally performed with the prior knowledge of planetary mass, radius, and bulk molar ratios of Fe/Mg and Si/Mg, we regenerate a substantial data set of interior structure data for rocky exoplanets and train a new MDN model with inputs of planetary mass, radius, Fe/Mg, and Si/Mg. It has been found that the well-trained MDN model has comparable performance to that of the MCMC method but requires significantly less computation time. The MDN model presents a practical alternative to the traditional MCMC method, surpassing the latter with minimal requirements for specialized knowledge, faster prediction, and greater adaptability. The developed MDN model is made publicly available on GitHub for the broader scientific community’s utilization. With the advent of the James Webb Space Telescope, we are ushering in a new epoch in exoplanetary explorations. In this evolving landscape, the MDN model stands out as a valuable asset, particularly for its ability to rapidly assimilate and interpret new data, thereby substantially advancing our understanding of the interior and habitability of exoplanetary systems.
{"title":"Comparison of Machine-learning and Bayesian Inferences for the Interior of Rocky Exoplanets with Large Compositional Diversity","authors":"Yong Zhao, Zibo Liu, Dongdong Ni and Zhiyuan Chen","doi":"10.3847/1538-4365/ad3f1c","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3f1c","url":null,"abstract":"In previous work, we demonstrated that machine-learning techniques based on mixture density networks (MDNs) are successful in inferring the interior structure of rocky exoplanets with large compositional diversity. In this study, we compare the performance of a well-trained MDN model with the conventional Bayesian inversion method based on the Markov chain Monte Carlo (MCMC) method, under the same observable constraints. Considering that MCMC inversion is generally performed with the prior knowledge of planetary mass, radius, and bulk molar ratios of Fe/Mg and Si/Mg, we regenerate a substantial data set of interior structure data for rocky exoplanets and train a new MDN model with inputs of planetary mass, radius, Fe/Mg, and Si/Mg. It has been found that the well-trained MDN model has comparable performance to that of the MCMC method but requires significantly less computation time. The MDN model presents a practical alternative to the traditional MCMC method, surpassing the latter with minimal requirements for specialized knowledge, faster prediction, and greater adaptability. The developed MDN model is made publicly available on GitHub for the broader scientific community’s utilization. With the advent of the James Webb Space Telescope, we are ushering in a new epoch in exoplanetary explorations. In this evolving landscape, the MDN model stands out as a valuable asset, particularly for its ability to rapidly assimilate and interpret new data, thereby substantially advancing our understanding of the interior and habitability of exoplanetary systems.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192623","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 : 2024-05-28DOI: 10.3847/1538-4365/ad454a
A. G. Nouri, Y. Liu, P. Givi, H. Babaee and D. Livescu
A novel methodology is developed to extract accurate skeletal reaction models for nuclear combustion. Local sensitivities of isotope mass fractions with respect to reaction rates are modeled based on the forced optimally time-dependent (f-OTD) scheme. These sensitivities are then analyzed temporally to generate skeletal models. The methodology is demonstrated by conducting skeletal reduction of constant density and temperature burning of carbon and oxygen relevant to Type Ia supernovae (SNe Ia). The 495-isotopes Torch model is chosen as the detailed reaction network. A map of maximum production of 56Ni in SNe Ia is produced for different temperatures, densities, and proton-to-neutron ratios. The f-OTD simulations and the sensitivity analyses are then performed with initial conditions from this map. A series of skeletal models are derived and their performances are assessed by comparison against currently existing skeletal models. Previous models have been constructed intuitively by assuming the dominance of α-chain reactions. The comparison of the newly generated skeletal models against previous models is based on the predicted energy release and 44Ti and 56Ni abundances by each model. The consequences of ye ≠ 0.5 in the initial composition are also explored where ye is the electron fraction. The simulated results show that 56Ni production decreases by decreasing ye as expected, and that the 43Sc is a key isotope in proton and neutron channels toward 56Ni production. It is shown that an f-OTD skeletal model with 150 isotopes can accurately predict the 56Ni abundance in SNe Ia for ye ≲ 0.5 initial conditions.
我们开发了一种新方法来提取核燃烧的精确骨架反应模型。同位素质量分数对反应速率的局部敏感性是基于强制最优时间依赖（f-OTD）方案建模的。然后对这些敏感性进行时间分析，生成骨架模型。通过对与 Ia 型超新星（SNe Ia）相关的碳和氧的恒定密度和温度燃烧进行骨架还原，对该方法进行了演示。选择 495 同位素 Torch 模型作为详细反应网络。根据不同的温度、密度和质子-中子比，绘制了Ia型超新星中56Ni的最大生成图。然后根据该图中的初始条件进行 f-OTD 模拟和敏感性分析。得出了一系列骨架模型，并通过与现有骨架模型的比较评估了它们的性能。以前的模型是通过假设 α 链反应占主导地位而直观构建的。新生成的骨架模型与以前模型的比较是基于每个模型预测的能量释放以及 44Ti 和 56Ni 丰度。还探讨了初始成分中 ye ≠ 0.5 的后果，其中 ye 是电子分数。模拟结果表明，正如所预期的那样，56Ni 的生成量会随着 ye 的减小而减少，而且 43Sc 是质子和中子通向 56Ni 生成的关键同位素。结果表明，在ye ≲ 0.5的初始条件下，包含150个同位素的f-OTD骨架模型可以准确预测SNe Ia中的56Ni丰度。
{"title":"Skeletal Kinetics Reduction for Astrophysical Reaction Networks","authors":"A. G. Nouri, Y. Liu, P. Givi, H. Babaee and D. Livescu","doi":"10.3847/1538-4365/ad454a","DOIUrl":"https://doi.org/10.3847/1538-4365/ad454a","url":null,"abstract":"A novel methodology is developed to extract accurate skeletal reaction models for nuclear combustion. Local sensitivities of isotope mass fractions with respect to reaction rates are modeled based on the forced optimally time-dependent (f-OTD) scheme. These sensitivities are then analyzed temporally to generate skeletal models. The methodology is demonstrated by conducting skeletal reduction of constant density and temperature burning of carbon and oxygen relevant to Type Ia supernovae (SNe Ia). The 495-isotopes Torch model is chosen as the detailed reaction network. A map of maximum production of 56Ni in SNe Ia is produced for different temperatures, densities, and proton-to-neutron ratios. The f-OTD simulations and the sensitivity analyses are then performed with initial conditions from this map. A series of skeletal models are derived and their performances are assessed by comparison against currently existing skeletal models. Previous models have been constructed intuitively by assuming the dominance of α-chain reactions. The comparison of the newly generated skeletal models against previous models is based on the predicted energy release and 44Ti and 56Ni abundances by each model. The consequences of ye ≠ 0.5 in the initial composition are also explored where ye is the electron fraction. The simulated results show that 56Ni production decreases by decreasing ye as expected, and that the 43Sc is a key isotope in proton and neutron channels toward 56Ni production. It is shown that an f-OTD skeletal model with 150 isotopes can accurately predict the 56Ni abundance in SNe Ia for ye ≲ 0.5 initial conditions.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"205 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The James Webb Space Telescope provides an unprecedented opportunity for unbiased surveys of Hα-emitting galaxies at z > 4 with the NIRCam's wide-field slitless spectroscopy (WFSS). In this work, we present a census of Lyα escape fraction (fesc,Lyα) of 165 star-forming galaxies at z = 4.9–6.3, utilizing their Hα emission directly measured from FRESCO NIRCam/WFSS data. We search for Lyα emission of each Hα-emitting galaxy in the Very Large Telescope/MUSE data. The overall fesc,Lyα measured by stacking is 0.090 ± 0.006. We find that fesc,Lyα displays a strong dependence on the observed UV slope (βobs) and E(B − V), such that the bluest galaxies (βobs ∼ −2.5) have the largest escape fractions (fesc,Lyα ≈ 0.6), indicative of the crucial role of dust and gas in modulating the escape of Lyα photons. fesc,Lyα is less well related to other parameters, including the UV luminosity and stellar mass, and the variation in fesc,Lyα with them can be explained by their underlying coupling with E(B − V) or βobs. Our results suggest a tentative decline in fesc,Lyα at z ≳ 5, implying increasing intergalactic medium attenuation toward higher redshift. Furthermore, the dependence of fesc,Lyα on βobs is proportional to that of the ionizing photon escape fraction (fesc,LyC), indicating that the escape of Lyα and ionizing photon may be regulated by similar physical processes. With fesc,Lyα as a proxy to fesc,LyC, we infer that UV-faint (MUV > −16) galaxies contribute >70% of the total ionizing emissivity at z = 5–6. If these relations hold during the epoch of reionization, UV-faint galaxies can contribute the majority of UV photon budget to reionize the Universe.
{"title":"Quantifying the Escape of Lyα at z ≈ 5–6: A Census of Lyα Escape Fraction with Hα-emitting Galaxies Spectroscopically Confirmed by JWST and VLT/MUSE","authors":"Xiaojing Lin, Zheng Cai, Yunjing Wu, Zihao Li, Fengwu Sun, Xiaohui Fan, Zuyi Chen, Mingyu Li, Fuyan Bian, Yuanhang Ning, Linhua Jiang, Gustavo Bruzual, Stephane Charlot and Jacopo Chevallard","doi":"10.3847/1538-4365/ad3e7d","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3e7d","url":null,"abstract":"The James Webb Space Telescope provides an unprecedented opportunity for unbiased surveys of Hα-emitting galaxies at z > 4 with the NIRCam's wide-field slitless spectroscopy (WFSS). In this work, we present a census of Lyα escape fraction (fesc,Lyα) of 165 star-forming galaxies at z = 4.9–6.3, utilizing their Hα emission directly measured from FRESCO NIRCam/WFSS data. We search for Lyα emission of each Hα-emitting galaxy in the Very Large Telescope/MUSE data. The overall fesc,Lyα measured by stacking is 0.090 ± 0.006. We find that fesc,Lyα displays a strong dependence on the observed UV slope (βobs) and E(B − V), such that the bluest galaxies (βobs ∼ −2.5) have the largest escape fractions (fesc,Lyα ≈ 0.6), indicative of the crucial role of dust and gas in modulating the escape of Lyα photons. fesc,Lyα is less well related to other parameters, including the UV luminosity and stellar mass, and the variation in fesc,Lyα with them can be explained by their underlying coupling with E(B − V) or βobs. Our results suggest a tentative decline in fesc,Lyα at z ≳ 5, implying increasing intergalactic medium attenuation toward higher redshift. Furthermore, the dependence of fesc,Lyα on βobs is proportional to that of the ionizing photon escape fraction (fesc,LyC), indicating that the escape of Lyα and ionizing photon may be regulated by similar physical processes. With fesc,Lyα as a proxy to fesc,LyC, we infer that UV-faint (MUV > −16) galaxies contribute >70% of the total ionizing emissivity at z = 5–6. If these relations hold during the epoch of reionization, UV-faint galaxies can contribute the majority of UV photon budget to reionize the Universe.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141171409","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 : 2024-05-23DOI: 10.3847/1538-4365/ad4484
A. Polanski, J. Lubin, C. Beard, Joseph M. Akana Murphy, R. Rubenzahl, M. Hill, I. Crossfield, A. Chontos, P. Robertson, H. Isaacson, S. R. Kane, D. Ciardi, N. Batalha, C. Dressing, B. Fulton, Andrew W. Howard, Dan Huber, E. Petigura, L. Weiss, Isabel Angelo, A. Behmard, S. Blunt, C. Brinkman, Fei Dai, P. Dalba, T. Fetherolf, S. Giacalone, L. Hirsch, R. Holcomb, M. Kosiarek, A. Mayo, M. MacDougall, T. Močnik, D. Pidhorodetska, M. Rice, L. Rosenthal, N. Scarsdale, E. Turtelboom, Dakotah B. Tyler, Judah Van Zandt, S. Yee, D. R. Coria, Shannon D. Dulz, J. Hartman, Aaron Householder, Sarah Lange, Andrew Langford, Emma M. Louden, Jared C. Siegel, E. Gilbert, E. Gonzales, J. Schlieder, A. Boyle, J. Christiansen, Catherine A. Clark, Rachel B. Fernandes, M. Lund, A. Savel, H. Gill, C. Beichman, R. Matson, E. Matthews, E. Furlan, S. Howell, N. Scott, M. Everett, J. Livingston, I. O. Ershova, D. Cheryasov, B. Safonov, J. Lillo-Box, D. Barrado, M. Morales-Calder'on
The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from Kepler. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data that has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached ≥5σ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three-year survey. We took the opportunity to assess the performance of our survey and found that we achieved many of our goals, including measuring the mass of 38 small (<4 R ⊕) planets, nearly achieving the TESS mission’s basic science requirement. In addition, we evaluated the performance of the Automated Planet Finder as survey support and observed meaningful constraints on system parameters, due to its more uniform phase coverage. Finally, we compared our measured masses to those predicted by commonly used mass–radius relations and investigated evidence of systematic bias.
{"title":"The TESS-Keck Survey. XX. 15 New TESS Planets and a Uniform RV Analysis of All Survey Targets","authors":"A. Polanski, J. Lubin, C. Beard, Joseph M. Akana Murphy, R. Rubenzahl, M. Hill, I. Crossfield, A. Chontos, P. Robertson, H. Isaacson, S. R. Kane, D. Ciardi, N. Batalha, C. Dressing, B. Fulton, Andrew W. Howard, Dan Huber, E. Petigura, L. Weiss, Isabel Angelo, A. Behmard, S. Blunt, C. Brinkman, Fei Dai, P. Dalba, T. Fetherolf, S. Giacalone, L. Hirsch, R. Holcomb, M. Kosiarek, A. Mayo, M. MacDougall, T. Močnik, D. Pidhorodetska, M. Rice, L. Rosenthal, N. Scarsdale, E. Turtelboom, Dakotah B. Tyler, Judah Van Zandt, S. Yee, D. R. Coria, Shannon D. Dulz, J. Hartman, Aaron Householder, Sarah Lange, Andrew Langford, Emma M. Louden, Jared C. Siegel, E. Gilbert, E. Gonzales, J. Schlieder, A. Boyle, J. Christiansen, Catherine A. Clark, Rachel B. Fernandes, M. Lund, A. Savel, H. Gill, C. Beichman, R. Matson, E. Matthews, E. Furlan, S. Howell, N. Scott, M. Everett, J. Livingston, I. O. Ershova, D. Cheryasov, B. Safonov, J. Lillo-Box, D. Barrado, M. Morales-Calder'on","doi":"10.3847/1538-4365/ad4484","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4484","url":null,"abstract":"\u0000 The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from Kepler. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data that has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached ≥5σ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three-year survey. We took the opportunity to assess the performance of our survey and found that we achieved many of our goals, including measuring the mass of 38 small (<4 R\u0000 ⊕) planets, nearly achieving the TESS mission’s basic science requirement. In addition, we evaluated the performance of the Automated Planet Finder as survey support and observed meaningful constraints on system parameters, due to its more uniform phase coverage. Finally, we compared our measured masses to those predicted by commonly used mass–radius relations and investigated evidence of systematic bias.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107951","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 : 2024-05-22DOI: 10.3847/1538-4365/ad3e81
Caleb K. Harada, Courtney D. Dressing, Stephen R. Kane and Bahareh Adami Ardestani
The Decadal Survey on Astronomy and Astrophysics 2020 has recommended that NASA realize a large IR/optical/UV space telescope optimized for high-contrast imaging and spectroscopy of ∼25 exo-Earths and transformative general astrophysics. The NASA Exoplanet Exploration Program (ExEP) has subsequently released a list of 164 nearby (d < 25 pc) targets deemed the most accessible to survey for potentially habitable exoplanets with the Habitable Worlds Observatory (HWO). We present a catalog of system properties for the 164 ExEP targets, including 1744 abundance measurements for 14 elements from the Hypatia Catalog and 924 photometry measurements spanning from 151.6 nm to 22 μm in the GALEX, Strömgren, Tycho, Gaia, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer bandpasses. We independently derive stellar properties for these systems by modeling their spectral energy distributions with Bayesian model averaging. Additionally, by consulting the literature, we identify TESS flare rates for 46 stars, optical variability for 78 stars, and X-ray emission for 46 stars in our sample. We discuss our catalog in the context of planet habitability and draw attention to key gaps in our knowledge where precursor science can help to inform HWO mission design trade studies in the near future. Notably, only 33 of the 164 stars in our sample have reliable space-based UV measurements, and only 40 have a mid-IR measurement. We also find that phosphorus, a bioessential element, has only been measured in 11 of these stars, motivating future abundance surveys. Our catalog is publicly available and we advocate for its use in future studies of promising HWO targets.
{"title":"Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets","authors":"Caleb K. Harada, Courtney D. Dressing, Stephen R. Kane and Bahareh Adami Ardestani","doi":"10.3847/1538-4365/ad3e81","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3e81","url":null,"abstract":"The Decadal Survey on Astronomy and Astrophysics 2020 has recommended that NASA realize a large IR/optical/UV space telescope optimized for high-contrast imaging and spectroscopy of ∼25 exo-Earths and transformative general astrophysics. The NASA Exoplanet Exploration Program (ExEP) has subsequently released a list of 164 nearby (d < 25 pc) targets deemed the most accessible to survey for potentially habitable exoplanets with the Habitable Worlds Observatory (HWO). We present a catalog of system properties for the 164 ExEP targets, including 1744 abundance measurements for 14 elements from the Hypatia Catalog and 924 photometry measurements spanning from 151.6 nm to 22 μm in the GALEX, Strömgren, Tycho, Gaia, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer bandpasses. We independently derive stellar properties for these systems by modeling their spectral energy distributions with Bayesian model averaging. Additionally, by consulting the literature, we identify TESS flare rates for 46 stars, optical variability for 78 stars, and X-ray emission for 46 stars in our sample. We discuss our catalog in the context of planet habitability and draw attention to key gaps in our knowledge where precursor science can help to inform HWO mission design trade studies in the near future. Notably, only 33 of the 164 stars in our sample have reliable space-based UV measurements, and only 40 have a mid-IR measurement. We also find that phosphorus, a bioessential element, has only been measured in 11 of these stars, motivating future abundance surveys. Our catalog is publicly available and we advocate for its use in future studies of promising HWO targets.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141147670","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 : 2024-05-21DOI: 10.3847/1538-4365/ad43d5
Jiangtao Wang, Jianrong Shi, Jianning Fu, Weikai Zong and Chunqian Li
Accurate determination of the stellar atmospheric parameters of RR Lyrae stars (RRLs) requires short individual exposures of the spectra to mitigate pulsation effects. We present improved template-matching methods to determine the stellar atmospheric parameters of RRLs from single-epoch spectra of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, also known as the Guoshoujing Telescope (LAMOST). We determine the radial velocities and stellar atmospheric parameters (effective temperature Teff, surface gravity , and metallicity [M/H]) of 10,486 and 1027 RRLs from 42,729 LAMOST low-resolution spectra (LRS) and 7064 LAMOST medium-resolution spectra (MRS), respectively. Our results are in good agreement with the parameters of other databases, where the external uncertainties of Teff, , and [M/H] for LRS/MRS are estimated to be 207/142 K, 0.21/0.16 dex, and 0.24/0.18 dex, respectively. We conclude with the variation characteristics of the radial velocities (RV) and stellar atmospheric parameters for RRLs during the pulsation phase. There is a significant difference of 28 ± 21 km s−1 between the peak-to-peak amplitude (Aptp) of RV from the Hα line (RVHα) and from metal lines (RVmetal) for RRab, whereas it is only 4 ± 17 km s−1 for RRc. The Aptp of Teff is 930 ± 456 and 409 ± 375 K for RRab and RRc, respectively. The of RRab shows a mild variation of approximately 0.22 ± 0.42 dex near the phase of φ = 0.9, while that of RRc almost remains constant. The [M/H] of RRab and RRc show a minor variation of about 0.25 ± 0.50 and 0.28 ± 0.55 dex, respectively, near the phase of φ = 0.9. We expect that the determined stellar atmospheric parameters would shed new light on the study of stellar evolution and pulsation, the structure of the Milky Way, as well as other research fields.
{"title":"Stellar Atmospheric Parameters of ∼11,000 RR Lyrae Stars from LAMOST Spectra","authors":"Jiangtao Wang, Jianrong Shi, Jianning Fu, Weikai Zong and Chunqian Li","doi":"10.3847/1538-4365/ad43d5","DOIUrl":"https://doi.org/10.3847/1538-4365/ad43d5","url":null,"abstract":"Accurate determination of the stellar atmospheric parameters of RR Lyrae stars (RRLs) requires short individual exposures of the spectra to mitigate pulsation effects. We present improved template-matching methods to determine the stellar atmospheric parameters of RRLs from single-epoch spectra of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, also known as the Guoshoujing Telescope (LAMOST). We determine the radial velocities and stellar atmospheric parameters (effective temperature Teff, surface gravity , and metallicity [M/H]) of 10,486 and 1027 RRLs from 42,729 LAMOST low-resolution spectra (LRS) and 7064 LAMOST medium-resolution spectra (MRS), respectively. Our results are in good agreement with the parameters of other databases, where the external uncertainties of Teff, , and [M/H] for LRS/MRS are estimated to be 207/142 K, 0.21/0.16 dex, and 0.24/0.18 dex, respectively. We conclude with the variation characteristics of the radial velocities (RV) and stellar atmospheric parameters for RRLs during the pulsation phase. There is a significant difference of 28 ± 21 km s−1 between the peak-to-peak amplitude (Aptp) of RV from the Hα line (RVHα) and from metal lines (RVmetal) for RRab, whereas it is only 4 ± 17 km s−1 for RRc. The Aptp of Teff is 930 ± 456 and 409 ± 375 K for RRab and RRc, respectively. The of RRab shows a mild variation of approximately 0.22 ± 0.42 dex near the phase of φ = 0.9, while that of RRc almost remains constant. The [M/H] of RRab and RRc show a minor variation of about 0.25 ± 0.50 and 0.28 ± 0.55 dex, respectively, near the phase of φ = 0.9. We expect that the determined stellar atmospheric parameters would shed new light on the study of stellar evolution and pulsation, the structure of the Milky Way, as well as other research fields.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141147702","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 : 2024-05-17DOI: 10.3847/1538-4365/ad3c39
J. Grace Clark, Kamil Hornoch, Allen W. Shafter, Hana Kučáková, Jan Vraštil, Peter Kušnirák, Marek Wolf
The results of a two-decade-long R-band photometric survey of novae in M31 are presented. From these data, R-band light curves have been determined for 180 novae with data sufficient for estimating the peak brightness and subsequent rate of decline. The data show a weak correlation of peak brightness with fade rate consistent with the well-known maximum magnitude versus rate of decline (MMRD) relation. As generally appreciated for Galactic novae, the large scatter in the MMRD relation precludes its use in determining distances to individual novae. The novae at maximum light are distributed with standard deviation σ = 0.89 mag about a mean R-band absolute magnitude given by 〈M R 〉 = −7.57 ± 0.07. The overall M31 luminosity distribution is in excellent agreement with that found for Galactic novae suggesting that the nova populations in M31 and the Galaxy are quite similar. The notion that all novae can be characterized by a standard luminosity 15 days after maximum light (M 15) is also explored. Surprisingly, the distribution of M 15 values is characterized by a standard deviation only slightly smaller than that for novae at maximum light and thus offers little promise for precise extragalactic distance determinations. A dozen faint and fast novae that are likely to be previously unidentified recurrent novae have been identified from their position in the MMRD plot and in the M 15 distribution.
本文介绍了对 M31 中的新星进行的长达二十年的 R 波段测光调查的结果。根据这些数据，确定了 180 个新星的 R 波段光变曲线，其数据足以估算峰值亮度和随后的衰减率。数据显示峰值亮度与衰减率之间存在微弱的相关性，这与众所周知的最大亮度与衰减率（MMRD）关系是一致的。正如银河系新星的普遍情况一样，MMRD 关系中的巨大散差使其无法用于确定单个新星的距离。新星最大亮度的标准偏差 σ = 0.89 等，围绕平均 R 波段绝对星等的分布为〈M R 〉 = -7.57 ± 0.07。M31的整体光度分布与银河系新星的光度分布非常吻合，这表明M31和银河系的新星群非常相似。我们还探讨了所有新星都可以用最大光后 15 天的标准光度（M 15）来表征的概念。出乎意料的是，M 15 值的分布特点是标准偏差仅比最大光时的新星标准偏差略小，因此对于精确的河外距离测定没有什么希望。根据它们在MMRD图和M 15分布图中的位置，我们确定了十几颗暗新星和快新星，它们很可能是以前未发现的周期新星。
{"title":"Exploring the Maximum Magnitude versus Rate of Decline Relation for Novae in M31","authors":"J. Grace Clark, Kamil Hornoch, Allen W. Shafter, Hana Kučáková, Jan Vraštil, Peter Kušnirák, Marek Wolf","doi":"10.3847/1538-4365/ad3c39","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3c39","url":null,"abstract":"\u0000 The results of a two-decade-long R-band photometric survey of novae in M31 are presented. From these data, R-band light curves have been determined for 180 novae with data sufficient for estimating the peak brightness and subsequent rate of decline. The data show a weak correlation of peak brightness with fade rate consistent with the well-known maximum magnitude versus rate of decline (MMRD) relation. As generally appreciated for Galactic novae, the large scatter in the MMRD relation precludes its use in determining distances to individual novae. The novae at maximum light are distributed with standard deviation σ = 0.89 mag about a mean R-band absolute magnitude given by 〈M\u0000 \u0000 R\u0000 〉 = −7.57 ± 0.07. The overall M31 luminosity distribution is in excellent agreement with that found for Galactic novae suggesting that the nova populations in M31 and the Galaxy are quite similar. The notion that all novae can be characterized by a standard luminosity 15 days after maximum light (M\u0000 15) is also explored. Surprisingly, the distribution of M\u0000 15 values is characterized by a standard deviation only slightly smaller than that for novae at maximum light and thus offers little promise for precise extragalactic distance determinations. A dozen faint and fast novae that are likely to be previously unidentified recurrent novae have been identified from their position in the MMRD plot and in the M\u0000 15 distribution.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140963508","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 : 2024-05-17DOI: 10.3847/1538-4365/ad3bad
T. Zastrocky, M. Brotherton, P. Du, J. McLane, K. A. Olson, D. A. Dale, H. Kobulnicky, J. Maithil, My L. Nguyen, W. Chick, David H. Kasper, Derek Hand, C. Adelman, Z. Carter, G. Murphree, M. Oeur, T. Roth, S. Schonsberg, M. Caradonna, J. Favro, A. J. Ferguson, I. M. Gonzalez, L. M. Hadding, H. D. Hagler, C. J. Rogers, T. R. Stack, Franklin Chapman, Dong-Wei Bao, Feng Fang, S. Zhai, Sen Yang, Yong-Jie Chen, Hua-Rui Bai, Yi-Xin Fu, Jun-Rong Liu, Zhu-Heng Yao, Yue-Chang Peng, Yu-Yang Songsheng, Yan-Rong Li, Jin-Ming Bai, Chen Hu, M. Xiao, Luis C. Ho, Jian-Min Wang
We report first-time reverberation-mapping results for 14 active galactic nuclei (AGNs) from the ongoing Monitoring AGNs with Hβ Asymmetry campaign (MAHA). These results utilize optical spectra obtained with the Long Slit Spectrograph on the Wyoming Infrared 2.3 m Telescope between 2017 November and 2023 May. MAHA combines long-duration monitoring with high cadence. We report results from multiple observing seasons for nine of the 14 objects. These results include Hβ time lags, supermassive black hole masses, and velocity-resolved time lags. The velocity-resolved lags allow us to investigate the kinematics of the broad-line region.
{"title":"Monitoring AGNs with Hβ Asymmetry. IV. First Reverberation Mapping Results of 14 Active Galactic Nuclei","authors":"T. Zastrocky, M. Brotherton, P. Du, J. McLane, K. A. Olson, D. A. Dale, H. Kobulnicky, J. Maithil, My L. Nguyen, W. Chick, David H. Kasper, Derek Hand, C. Adelman, Z. Carter, G. Murphree, M. Oeur, T. Roth, S. Schonsberg, M. Caradonna, J. Favro, A. J. Ferguson, I. M. Gonzalez, L. M. Hadding, H. D. Hagler, C. J. Rogers, T. R. Stack, Franklin Chapman, Dong-Wei Bao, Feng Fang, S. Zhai, Sen Yang, Yong-Jie Chen, Hua-Rui Bai, Yi-Xin Fu, Jun-Rong Liu, Zhu-Heng Yao, Yue-Chang Peng, Yu-Yang Songsheng, Yan-Rong Li, Jin-Ming Bai, Chen Hu, M. Xiao, Luis C. Ho, Jian-Min Wang","doi":"10.3847/1538-4365/ad3bad","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3bad","url":null,"abstract":"\u0000 We report first-time reverberation-mapping results for 14 active galactic nuclei (AGNs) from the ongoing Monitoring AGNs with Hβ Asymmetry campaign (MAHA). These results utilize optical spectra obtained with the Long Slit Spectrograph on the Wyoming Infrared 2.3 m Telescope between 2017 November and 2023 May. MAHA combines long-duration monitoring with high cadence. We report results from multiple observing seasons for nine of the 14 objects. These results include Hβ time lags, supermassive black hole masses, and velocity-resolved time lags. The velocity-resolved lags allow us to investigate the kinematics of the broad-line region.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"8 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140963939","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 : 2024-05-16DOI: 10.3847/1538-4365/ad4296
Kshitij S. Bane, I. V. Barve, G. Gireesh, C. Kathiravan, R. Ramesh
Recently we had reported commissioning of a prototype for pulsar observations at low radio frequencies (<100 MHz) using log-periodic dipole antennas in the Gauribidanur Radio Observatory (≈77°E, 14°N) near Bangalore in India (https://www.iiap.res.in/?q=centers/radio). The aforementioned system (the Gauribidanur Pulsar System) is currently being augmented to directly digitize the radio-frequency signals from the individual antennas in the array. Our initial results using a 1–bit raw voltage-recording system indicate that such a back-end receiver offers distinct advantages like (i) simultaneous observations of any set of desired directions in the sky with multiple offline beams and smaller data rate/volume, and (ii) archival of the observed data with minimal resources for reanalysis in the future, either in the same or a different set of directions in the sky.
{"title":"A 1–bit Raw Voltage-recording System for Dedicated Observations of Transients at Low Radio Frequencies","authors":"Kshitij S. Bane, I. V. Barve, G. Gireesh, C. Kathiravan, R. Ramesh","doi":"10.3847/1538-4365/ad4296","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4296","url":null,"abstract":"\u0000 Recently we had reported commissioning of a prototype for pulsar observations at low radio frequencies (<100 MHz) using log-periodic dipole antennas in the Gauribidanur Radio Observatory (≈77°E, 14°N) near Bangalore in India (https://www.iiap.res.in/?q=centers/radio). The aforementioned system (the Gauribidanur Pulsar System) is currently being augmented to directly digitize the radio-frequency signals from the individual antennas in the array. Our initial results using a 1–bit raw voltage-recording system indicate that such a back-end receiver offers distinct advantages like (i) simultaneous observations of any set of desired directions in the sky with multiple offline beams and smaller data rate/volume, and (ii) archival of the observed data with minimal resources for reanalysis in the future, either in the same or a different set of directions in the sky.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140967655","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 : 2024-05-14DOI: 10.3847/1538-4365/ad3936
Yue Shen, Catherine J. Grier, Keith Horne, Zachary Stone, Jennifer I. Li, Qian Yang, Yasaman Homayouni, Jonathan R. Trump, Scott F. Anderson, W. N. Brandt, Patrick B. Hall, Luis C. Ho, Linhua Jiang, Patrick Petitjean, Donald P. Schneider, Charling Tao, Fergus. R. Donnan, Yusra AlSayyad, Matthew A. Bershady, Michael R. Blanton, Dmitry Bizyaev, Kevin Bundy, Yuguang Chen, Megan C. Davis, Kyle Dawson, Xiaohui Fan, Jenny E. Greene, Hannes Gröller, Yucheng Guo, Héctor Ibarra-Medel, Yuanzhe Jiang, Ryan P. Keenan, Juna A. Kollmeier, Cassandra Lejoly, Zefeng Li, Axel de la Macorra, Maxwell Moe, Jundan Nie, Graziano Rossi, Paul S. Smith, Wei Leong Tee, Anne-Marie Weijmans, Jiachuan Xu, Minghao Yue, Xu Zhou, Zhimin Zhou and Hu Zou
We present the final data from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping (RM) project, a precursor to the SDSS-V Black Hole Mapper RM program. This data set includes 11 yr photometric and 7 yr spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1 < z < 4.5 and a luminosity range of Lbol = 1044−47.5 erg s−1, along with spectral and variability measurements. We report 23, 81, 125, and 110 RM lags (relative to optical continuum variability) for broad Hα, Hβ, Mg ii, and C iv using the SDSS-RM sample, spanning much of the luminosity and redshift ranges of the sample. Using 30 low-redshift RM active galactic nuclei with dynamical-modeling black hole masses, we derive a new estimate of the average virial factor of for the line dispersion measured from the rms spectrum. The intrinsic scatter of individual virial factors is 0.31 ± 0.07 dex, indicating a factor of 2 systematic uncertainty in RM black hole masses. Our lag measurements reveal significant R–L relations for Hβ and Mg ii at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of the R–L relation for C iv given the limited dynamic range in luminosity, we found substantially larger scatter in C iv lags at fixed L1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hβ, Mg ii, and C iv, which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hβ and Mg ii recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the C iv recipe. The intrinsic scatter of SE masses around RM masses is ∼0.45 dex for Hβ and Mg ii, increasing to ∼0.58 dex for C iv.
我们展示了斯隆数字巡天（SDSS）混响绘图（RM）项目的最终数据，该项目是SDSS-V黑洞绘图仪RM项目的前身。该数据集包括849个宽线类星体的11年光度光曲线和7年光谱光曲线，红移范围为0.1 < z < 4.5，光度范围为Lbol = 1044-47.5 erg s-1，以及光谱和变率测量数据。我们利用 SDSS-RM 样本报告了宽 Hα、Hβ、Mg ii 和 C iv 的 23、81、125 和 110 RM 滞后（相对于光学连续变率），横跨了样本的大部分光度和红移范围。利用 30 个具有动力学模拟黑洞质量的低红移 RM 活动星系核，我们推导出了从均方根光谱中测得的线色散的平均病毒因子的新估计值。单个病毒因子的内在散度为 0.31 ± 0.07 dex，表明 RM 黑洞质量的系统不确定性为 2 倍。我们的滞后测量揭示了高红移下 Hβ 和 Mg ii 的显著 R-L 关系，这与基于异质样本的最新测量结果一致。由于光度的动态范围有限，我们无法对C iv的R-L关系的斜率进行强有力的约束，但我们发现在固定的L1350下，C iv滞后的散度要大得多。利用SDSS-RM滞后样本，我们得出了改进的Hβ、Mg ii和C iv的单回质量（SE）公式，在我们样本探测的光度范围内，这些公式与它们各自的RM质量以及两条不同谱线的SE公式是一致的。在给定的 RM 质量下，新的 Hβ 和 Mg ii 配方是近似无偏的估计值，但 C iv 配方存在系统性偏差。Hβ和Mg ii的SE质量在RM质量附近的内在散度为∼0.45dex，C iv则增加到∼0.58dex。
{"title":"The Sloan Digital Sky Survey Reverberation Mapping Project: Key Results","authors":"Yue Shen, Catherine J. Grier, Keith Horne, Zachary Stone, Jennifer I. Li, Qian Yang, Yasaman Homayouni, Jonathan R. Trump, Scott F. Anderson, W. N. Brandt, Patrick B. Hall, Luis C. Ho, Linhua Jiang, Patrick Petitjean, Donald P. Schneider, Charling Tao, Fergus. R. Donnan, Yusra AlSayyad, Matthew A. Bershady, Michael R. Blanton, Dmitry Bizyaev, Kevin Bundy, Yuguang Chen, Megan C. Davis, Kyle Dawson, Xiaohui Fan, Jenny E. Greene, Hannes Gröller, Yucheng Guo, Héctor Ibarra-Medel, Yuanzhe Jiang, Ryan P. Keenan, Juna A. Kollmeier, Cassandra Lejoly, Zefeng Li, Axel de la Macorra, Maxwell Moe, Jundan Nie, Graziano Rossi, Paul S. Smith, Wei Leong Tee, Anne-Marie Weijmans, Jiachuan Xu, Minghao Yue, Xu Zhou, Zhimin Zhou and Hu Zou","doi":"10.3847/1538-4365/ad3936","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3936","url":null,"abstract":"We present the final data from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping (RM) project, a precursor to the SDSS-V Black Hole Mapper RM program. This data set includes 11 yr photometric and 7 yr spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1 < z < 4.5 and a luminosity range of Lbol = 1044−47.5 erg s−1, along with spectral and variability measurements. We report 23, 81, 125, and 110 RM lags (relative to optical continuum variability) for broad Hα, Hβ, Mg ii, and C iv using the SDSS-RM sample, spanning much of the luminosity and redshift ranges of the sample. Using 30 low-redshift RM active galactic nuclei with dynamical-modeling black hole masses, we derive a new estimate of the average virial factor of for the line dispersion measured from the rms spectrum. The intrinsic scatter of individual virial factors is 0.31 ± 0.07 dex, indicating a factor of 2 systematic uncertainty in RM black hole masses. Our lag measurements reveal significant R–L relations for Hβ and Mg ii at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of the R–L relation for C iv given the limited dynamic range in luminosity, we found substantially larger scatter in C iv lags at fixed L1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hβ, Mg ii, and C iv, which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hβ and Mg ii recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the C iv recipe. The intrinsic scatter of SE masses around RM masses is ∼0.45 dex for Hβ and Mg ii, increasing to ∼0.58 dex for C iv.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062505","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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