Hiroshi Imai, Yuhki Hamae, Kei Amada, Keisuke Nakashima, Ka-Yiu Shum, Rina Kasai, José F Gómez, Lucero Uscanga, Daniel Tafoya, Gabor Orosz, Ross A Burns
Abstract This paper describes an overview of the FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively monitor H2O (at 22 GHz) and SiO (at 43 GHz) masers associated with so-called “water fountain” sources. Here we show scientific results based on the data taken in the first five seasons of FLASHING, from 2018 December to 2023 April. We show the evolution of the H2O maser spectra, discovering new spectral components that break the record of the jet’s top speed and/or systematic velocity drifts in the spectrum indicating acceleration or deceleration of the maser gas clumps. For the 43 GHz SiO maser emission, we newly detect it in one source and find that it is no longer present in another source. This implies that the jets from these water fountains can be accelerated or decelerated, and show how circumstellar envelopes are destroyed.
摘要:本文概述了利用Nobeyama射电天文台45米望远镜推进的闪光灯(Nobeyama Generation of SiO-/H2O脉泽点火的最佳遗留收购)项目，该项目旨在集中监测H2O (22 GHz)和SiO (43 GHz)脉泽，这些脉泽与所谓的“喷泉”源有关。在这里，我们展示了基于flash前五个季节(2018年12月至2023年4月)数据的科学结果。我们展示了H2O脉泽光谱的演变，发现了新的光谱成分，这些成分打破了射流的最高速度和/或光谱中系统速度漂移的记录，表明了脉泽气体团块的加速或减速。对于43 GHz SiO脉泽发射，我们在一个源中新检测到它，发现它在另一个源中不再存在。这意味着这些喷泉的射流可以加速或减速，并显示了星周包层是如何被破坏的。
{"title":"FLASHING: Project overview","authors":"Hiroshi Imai, Yuhki Hamae, Kei Amada, Keisuke Nakashima, Ka-Yiu Shum, Rina Kasai, José F Gómez, Lucero Uscanga, Daniel Tafoya, Gabor Orosz, Ross A Burns","doi":"10.1093/pasj/psad064","DOIUrl":"https://doi.org/10.1093/pasj/psad064","url":null,"abstract":"Abstract This paper describes an overview of the FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively monitor H2O (at 22 GHz) and SiO (at 43 GHz) masers associated with so-called “water fountain” sources. Here we show scientific results based on the data taken in the first five seasons of FLASHING, from 2018 December to 2023 April. We show the evolution of the H2O maser spectra, discovering new spectral components that break the record of the jet’s top speed and/or systematic velocity drifts in the spectrum indicating acceleration or deceleration of the maser gas clumps. For the 43 GHz SiO maser emission, we newly detect it in one source and find that it is no longer present in another source. This implies that the jets from these water fountains can be accelerated or decelerated, and show how circumstellar envelopes are destroyed.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"50 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135696069","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 One of the key questions on active galactic nuclei (AGN) in galaxy clusters is how AGN could affect the formation and evolution of member galaxies and galaxy clusters in the history of the Universe. To address this issue, we investigate the dependence of AGN number fraction (fAGN) on cluster redshift (zcl) and distance from the cluster center (R$/$R200). We focus on more than 27000 galaxy groups and clusters at 0.1 < zcl < 1.4 with more than 1 million member galaxies selected from the Subaru Hyper Suprime-Cam. By combining various AGN selection methods based on infrared (IR), radio, and X-ray data, we identify 2688 AGN. We find that (i) fAGN increases with zcl and (ii) fAGN decreases with R$/$R200. The main contributors to the rapid increase of fAGN towards high-z and cluster center are IR- and radio-selected AGN, respectively. These results indicate that the emergence of the AGN population depends on the environment and redshift, and galaxy groups and clusters at high z play an important role in AGN evolution. We also find that cluster–cluster mergers may not drive AGN activity in at least the cluster center, while we have tentative evidence that cluster–cluster mergers could enhance AGN activity in the outskirts of (particularly massive) galaxy clusters.
{"title":"AGN number fraction in galaxy groups and clusters at <i>z</i> &lt; 1.4 from the Subaru Hyper Suprime-Cam survey","authors":"Aoi Hashiguchi, Yoshiki Toba, Naomi Ota, Masamune Oguri, Nobuhiro Okabe, Yoshihiro Ueda, Masatoshi Imanishi, Satoshi Yamada, Tomotsugu Goto, Shuhei Koyama, Kianhong Lee, Ikuyuki Mitsuishi, Tohru Nagao, Atsushi J Nishizawa, Akatoki Noboriguchi, Taira Oogi, Koki Sakuta, Malte Schramm, Mio Shibata, Yuichi Terashima, Takuji Yamashita, Anri Yanagawa, Anje Yoshimoto","doi":"10.1093/pasj/psad066","DOIUrl":"https://doi.org/10.1093/pasj/psad066","url":null,"abstract":"Abstract One of the key questions on active galactic nuclei (AGN) in galaxy clusters is how AGN could affect the formation and evolution of member galaxies and galaxy clusters in the history of the Universe. To address this issue, we investigate the dependence of AGN number fraction (fAGN) on cluster redshift (zcl) and distance from the cluster center (R$/$R200). We focus on more than 27000 galaxy groups and clusters at 0.1 &lt; zcl &lt; 1.4 with more than 1 million member galaxies selected from the Subaru Hyper Suprime-Cam. By combining various AGN selection methods based on infrared (IR), radio, and X-ray data, we identify 2688 AGN. We find that (i) fAGN increases with zcl and (ii) fAGN decreases with R$/$R200. The main contributors to the rapid increase of fAGN towards high-z and cluster center are IR- and radio-selected AGN, respectively. These results indicate that the emergence of the AGN population depends on the environment and redshift, and galaxy groups and clusters at high z play an important role in AGN evolution. We also find that cluster–cluster mergers may not drive AGN activity in at least the cluster center, while we have tentative evidence that cluster–cluster mergers could enhance AGN activity in the outskirts of (particularly massive) galaxy clusters.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135133417","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 Large solar flares occasionally trigger significant space-weather disturbances that affect the technological infrastructures of modern civilization, and therefore require further investigation. Although these solar flares have been monitored by satellite observations since the 1970s, large solar flares occur only infrequently and restrict systematic statistical research owing to data limitations. However, Toyokawa Observatory has operated solar radio observations at low frequencies (at 3.75 and 9.4 GHz) since 1951 and captured the early great flares as solar radio bursts. To estimate the magnitudes of flares that occurred before the start of solar X-ray (SXR) observations with the Geostationary Operational Environmental Satellite (GOES) satellites, we show the relationship between microwave fluxes at 3.75 and 9.4 GHz and X-ray fluxes of flares that occurred after 1988. In total, we explored 341 solar flares observed with the Nobeyama Radio Polarimeters and Toyokawa Observatory from 1988–2014 and compared them with the SXR observations recorded by the GOES satellites. The correlation coefficient was approximately 0.7. Therefore, the GOES X-ray class can be estimated from the peak flux at 3.75 and 9.4 GHz with a large variance and an error of factor of 3 (1σ). Thus, for the first time, we quantitatively estimated the light curves of two early solar flares observed in 1956 February by the Toyokawa solar radio observations using the relationship between SXR thermal radiation and microwave nonthermal radiation (Neupert, 1968, ApJ, 153, 59).
{"title":"Relationship of peak fluxes of solar radio bursts and X-ray class of solar flares: Application to early great solar flares","authors":"Keitarou Matsumoto, Satoshi Masuda, Masumi Shimojo, Hisashi Hayakawa","doi":"10.1093/pasj/psad058","DOIUrl":"https://doi.org/10.1093/pasj/psad058","url":null,"abstract":"Abstract Large solar flares occasionally trigger significant space-weather disturbances that affect the technological infrastructures of modern civilization, and therefore require further investigation. Although these solar flares have been monitored by satellite observations since the 1970s, large solar flares occur only infrequently and restrict systematic statistical research owing to data limitations. However, Toyokawa Observatory has operated solar radio observations at low frequencies (at 3.75 and 9.4 GHz) since 1951 and captured the early great flares as solar radio bursts. To estimate the magnitudes of flares that occurred before the start of solar X-ray (SXR) observations with the Geostationary Operational Environmental Satellite (GOES) satellites, we show the relationship between microwave fluxes at 3.75 and 9.4 GHz and X-ray fluxes of flares that occurred after 1988. In total, we explored 341 solar flares observed with the Nobeyama Radio Polarimeters and Toyokawa Observatory from 1988–2014 and compared them with the SXR observations recorded by the GOES satellites. The correlation coefficient was approximately 0.7. Therefore, the GOES X-ray class can be estimated from the peak flux at 3.75 and 9.4 GHz with a large variance and an error of factor of 3 (1σ). Thus, for the first time, we quantitatively estimated the light curves of two early solar flares observed in 1956 February by the Toyokawa solar radio observations using the relationship between SXR thermal radiation and microwave nonthermal radiation (Neupert, 1968, ApJ, 153, 59).","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135132304","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 The main purpose of the present paper is to list all the solar eclipses which took place in the first half of the 15th century, to list all the available records of observation of these eclipses, and, by using the multiply observed or contemporaneously observed solar eclipses, to determine ΔT for a few periods of the first half of the 15th century. We make the table using solar eclipse records from East Asia (China, Korea, and Japan), India, West Asia, and Europe, though the table is not perfect because the compilation of records is not complete in some of the relevant areas. We evaluate the reliability of the Chinese records of solar eclipses. The Chinese official history book, the Mingshi, records visible eclipses, while it does not record invisible eclipses. A simple analysis shows that the reliability of the book is $97%$. The marginally observable eclipses in China are useful for us to determine ΔT. We briefly consider the Māori eclipse observed in 1409. We extract the multiply observed eclipses and check whether these are useful for determining the value of ΔT. Finally, with newly added records of solar eclipses, we re-determine the value range of ΔT during the years 1431–1433 (see Tanikawa et al. 2019, in Proc. 5th Symposium on Historical Astronomical Records and Modern Science), and add a new ΔT in the year 1445.
本文的主要目的是列出15世纪上半叶发生的所有日食，列出所有可获得的日食观测记录，并利用多次观测或同时观测的日食来确定15世纪上半叶的几个时期的ΔT。我们使用东亚(中国、韩国和日本)、印度、西亚和欧洲的日食记录制作了这个表，尽管由于一些相关地区的记录汇编不完整，这个表并不完善。我们评估了中国日食记录的可靠性。中国的官方史书《明史》记载了可见的日食，而没有记载不可见的日食。简单的分析表明，这本书的可靠性为97%。在中国边际观测到的日食对我们确定ΔT很有用。我们简单地考虑一下1409年观测到的Māori日食。我们提取多次观测到的日食，并检查它们是否有助于确定ΔT的值。最后，通过新增加的日食记录，我们重新确定了ΔT在1431-1433年间的值范围(见Tanikawa et al. 2019, Proc. 5th Symposium on Historical Astronomical records and Modern Science)，并在1445年增加了一个新的ΔT。
{"title":"Solar eclipses observed worldwide in the first half of the 15th century and Δ<i>T</i> determined from multiply observed eclipses","authors":"Kiyotaka Tanikawa, Mitsuru Sôma, Ockie Simmonds, Kiyomi Iwahashi","doi":"10.1093/pasj/psad036","DOIUrl":"https://doi.org/10.1093/pasj/psad036","url":null,"abstract":"Abstract The main purpose of the present paper is to list all the solar eclipses which took place in the first half of the 15th century, to list all the available records of observation of these eclipses, and, by using the multiply observed or contemporaneously observed solar eclipses, to determine ΔT for a few periods of the first half of the 15th century. We make the table using solar eclipse records from East Asia (China, Korea, and Japan), India, West Asia, and Europe, though the table is not perfect because the compilation of records is not complete in some of the relevant areas. We evaluate the reliability of the Chinese records of solar eclipses. The Chinese official history book, the Mingshi, records visible eclipses, while it does not record invisible eclipses. A simple analysis shows that the reliability of the book is $97%$. The marginally observable eclipses in China are useful for us to determine ΔT. We briefly consider the Māori eclipse observed in 1409. We extract the multiply observed eclipses and check whether these are useful for determining the value of ΔT. Finally, with newly added records of solar eclipses, we re-determine the value range of ΔT during the years 1431–1433 (see Tanikawa et al. 2019, in Proc. 5th Symposium on Historical Astronomical Records and Modern Science), and add a new ΔT in the year 1445.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886878","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 We present the first results from GALAXY CRUISE, a community (or citizen) science project based on data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). The current paradigm of galaxy evolution suggests that galaxies grow hierarchically via mergers, but our observational understanding of the role of mergers is still limited. The data from HSC-SSP are ideally suited to improve our understanding with improved identifications of interacting galaxies thanks to the superb depth and image quality of HSC-SSP. We launched a community science project, GALAXY CRUISE, in 2019 and have collected over two million independent classifications of 20686 galaxies at z < 0.2. We first characterize the accuracy of the participants’ classifications and demonstrate that it surpasses previous studies based on shallower imaging data. We then investigate various aspects of interacting galaxies in detail. We show that there is a clear sign of enhanced activities of super-massive black holes and star formation in interacting galaxies compared to those in isolated galaxies. The enhancement seems particularly strong for galaxies undergoing violent mergers. We also show that the mass growth rate inferred from our results is roughly consistent with the observed evolution of the stellar mass function. The second season of GALAXY CRUISE is currently underway and we conclude with future prospects. We make the morphological classification catalog used in this paper publicly available at the GALAXY CRUISE website, which will be particularly useful for machine-learning applications.
{"title":"Galaxy Cruise: Deep Insights into Interacting Galaxies in the Local Universe","authors":"Masayuki Tanaka, Michitaro Koike, Sei’ichiro Naito, Junko Shibata, Kumiko Usuda-Sato, Hitoshi Yamaoka, Makoto Ando, Kei Ito, Umi Kobayashi, Yutaro Kofuji, Atsuki Kuwata, Suzuka Nakano, Rhythm Shimakawa, Ken-ichi Tadaki, Suguru Takebayashi, Chie Tsuchiya, Tomofumi Umemoto, Connor Bottrell","doi":"10.1093/pasj/psad055","DOIUrl":"https://doi.org/10.1093/pasj/psad055","url":null,"abstract":"Abstract We present the first results from GALAXY CRUISE, a community (or citizen) science project based on data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). The current paradigm of galaxy evolution suggests that galaxies grow hierarchically via mergers, but our observational understanding of the role of mergers is still limited. The data from HSC-SSP are ideally suited to improve our understanding with improved identifications of interacting galaxies thanks to the superb depth and image quality of HSC-SSP. We launched a community science project, GALAXY CRUISE, in 2019 and have collected over two million independent classifications of 20686 galaxies at z &lt; 0.2. We first characterize the accuracy of the participants’ classifications and demonstrate that it surpasses previous studies based on shallower imaging data. We then investigate various aspects of interacting galaxies in detail. We show that there is a clear sign of enhanced activities of super-massive black holes and star formation in interacting galaxies compared to those in isolated galaxies. The enhancement seems particularly strong for galaxies undergoing violent mergers. We also show that the mass growth rate inferred from our results is roughly consistent with the observed evolution of the stellar mass function. The second season of GALAXY CRUISE is currently underway and we conclude with future prospects. We make the morphological classification catalog used in this paper publicly available at the GALAXY CRUISE website, which will be particularly useful for machine-learning applications.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135719023","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}
Hiroyuki Masaki, Hideyuki Hotta, Yukio Katsukawa, Ryohtaroh T Ishikawa
Abstract We suggest a method that evaluates the horizontal velocity in the solar photosphere with easily observable values using a combination of neural network and radiative magnetohydrodynamics simulations. All three-component velocities of thermal convection on the solar surface have important roles in generating waves in the upper atmosphere. However, the velocity perpendicular to the line of sight (LoS) is difficult to observe. To deal with this problem, the local correlation tracking (LCT) method, which employs the difference between two images, has been widely used, but this method has several disadvantages. We develop a method that evaluates the horizontal velocity from a snapshot of the intensity and the LoS velocity with a neural network. We use data from numerical simulations for training the neural network. While two consecutive intensity images are required for LCT, our network needs just one intensity image at only a specific moment for input. From these input arrays, our network outputs a same-size array of a two-component velocity field. With only the intensity data, the network achieves a high correlation coefficient between the simulated and evaluated velocities of 0.83. In addition, the network performance can be improved when we add LoS velocity for input, enabling us to achieve a correlation coefficient of 0.90. Our method is also applied to observed data.
{"title":"Solar horizontal flow evaluation using neural network and numerical simulations with snapshot data","authors":"Hiroyuki Masaki, Hideyuki Hotta, Yukio Katsukawa, Ryohtaroh T Ishikawa","doi":"10.1093/pasj/psad063","DOIUrl":"https://doi.org/10.1093/pasj/psad063","url":null,"abstract":"Abstract We suggest a method that evaluates the horizontal velocity in the solar photosphere with easily observable values using a combination of neural network and radiative magnetohydrodynamics simulations. All three-component velocities of thermal convection on the solar surface have important roles in generating waves in the upper atmosphere. However, the velocity perpendicular to the line of sight (LoS) is difficult to observe. To deal with this problem, the local correlation tracking (LCT) method, which employs the difference between two images, has been widely used, but this method has several disadvantages. We develop a method that evaluates the horizontal velocity from a snapshot of the intensity and the LoS velocity with a neural network. We use data from numerical simulations for training the neural network. While two consecutive intensity images are required for LCT, our network needs just one intensity image at only a specific moment for input. From these input arrays, our network outputs a same-size array of a two-component velocity field. With only the intensity data, the network achieves a high correlation coefficient between the simulated and evaluated velocities of 0.83. In addition, the network performance can be improved when we add LoS velocity for input, enabling us to achieve a correlation coefficient of 0.90. Our method is also applied to observed data.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135957973","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 We conducted a multi-epoch very long baseline interferometry (VLBI) observation of 22 GHz H2O maser sources, which are associated with the Sagittarius B2 (Sgr B2) complex, one of the most active star-forming regions in the Galactic center. Using the VLBI exploration of radio astrometry (VERA) array, we detected 29, 90, and seven maser features in Sgr B2(North), (Main), and (South), respectively. We also discovered two H2O maser features in Sgr B2 (Mid-North). Moreover, we successfully measured spatial distributions and internal motions of the H2O maser sources in Sgr B2(M). We then discovered that the H2O maser features in Sgr B2(M) are located at the outer edge of H ii regions detected by using the centimeter radio continuum emission, and observationally demonstrated that they have outward motions from the two H ii regions separated by 1′. We obtained an absolute proper motion of (μαcos δ, μδ) = (−2.17 ± 0.03, −2.63 ± 0.06) mas yr−1 and marginally detected a parallax of Sgr B2, which is consistent with other measurements. The absolute proper motion corrected by the internal motions of the H2O maser features implies that the Sgr B2 complex is located at the near side of the Galactic center and is moving toward the positive galactic longitude. We estimate that Sgr B2 is at 160 ± 10 pc in front of Sgr A* by assuming a simple circular orbit of the central molecular zone (CMZ).
{"title":"Water maser distributions and their internal motions in the Sagittarius B2 complex","authors":"Daisuke Sakai, Tomoaki Oyama, Takumi Nagayama, Mareki Honma, Hideyuki Kobayashi","doi":"10.1093/pasj/psad052","DOIUrl":"https://doi.org/10.1093/pasj/psad052","url":null,"abstract":"Abstract We conducted a multi-epoch very long baseline interferometry (VLBI) observation of 22 GHz H2O maser sources, which are associated with the Sagittarius B2 (Sgr B2) complex, one of the most active star-forming regions in the Galactic center. Using the VLBI exploration of radio astrometry (VERA) array, we detected 29, 90, and seven maser features in Sgr B2(North), (Main), and (South), respectively. We also discovered two H2O maser features in Sgr B2 (Mid-North). Moreover, we successfully measured spatial distributions and internal motions of the H2O maser sources in Sgr B2(M). We then discovered that the H2O maser features in Sgr B2(M) are located at the outer edge of H ii regions detected by using the centimeter radio continuum emission, and observationally demonstrated that they have outward motions from the two H ii regions separated by 1′. We obtained an absolute proper motion of (μαcos δ, μδ) = (−2.17 ± 0.03, −2.63 ± 0.06) mas yr−1 and marginally detected a parallax of Sgr B2, which is consistent with other measurements. The absolute proper motion corrected by the internal motions of the H2O maser features implies that the Sgr B2 complex is located at the near side of the Galactic center and is moving toward the positive galactic longitude. We estimate that Sgr B2 is at 160 ± 10 pc in front of Sgr A* by assuming a simple circular orbit of the central molecular zone (CMZ).","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136314002","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 We present the orbital period variability and evolutionary status of the W UMa-type binary system V864 Mon from accurately measured fundamental parameters. New BV photometric observations of this system were performed in 2019 January and 2022 January, and the first high-resolution spectroscopic observations were carried out on three nights between 2019 January and March. A total of 29 times of minimum light were collected to examine the behavior of the orbital period. Our analysis of these timings indicates a continuous period increase at a rate of +2.62 × 10−7 d yr−1 over the past 20 years, which can be interpreted as a mass transfer from the less massive primary to the secondary component with a rate of 1.22 × 10−7 M⊙ yr−1. We measured the radial velocities (RVs) for both components, and determined the effective temperature and projected rotational velocity of the more massive secondary star to be Teff,2 = 5450 ± 94 K and v2sin i = 192 ± 40 km s−1, respectively, from the comparison of the observed spectrum at the primary minimum and the theoretical models. The individual masses and radii of both components were determined from a simultaneous analysis of the light and RV curves, which are M1 = 0.34 ± 0.02 M⊙, R1 = 0.69 ± 0.01 R⊙, and M2 = 1.06 ± 0.04 M⊙, R2 = 1.16 ± 0.02 R⊙, respectively. Our results indicate that V864 Mon is a W-subtype of W UMa stars with time-varying spot activity. The positions in the mass-luminosity and mass-radius diagrams indicate that the secondary star belongs to the main-sequence region, while the hotter primary is located beyond the terminal-age main sequence.
摘要从精确测量的基本参数出发，给出了wuma型双星系统V864 Mon的轨道周期变化及其演化状态。2019年1月和2022年1月对该系统进行了新的BV光度观测，并在2019年1月至3月的三个晚上进行了首次高分辨率光谱观测。总共收集了29次最小光来检查轨道周期的行为。我们对这些时间的分析表明，在过去的20年中，周期以+2.62 × 10−7 d yr−1的速率连续增加，这可以解释为质量从质量较小的主成分向次成分的转移，速率为1.22 × 10−7 M⊙yr−1。我们测量了这两个组分的径向速度(RVs)，并通过对主最小值和理论模型观测光谱的比较，确定了更大质量的副恒星Teff的有效温度和投影转速，分别为2 = 5450±94 K和v2sin i = 192±40 km s−1。同时对光和RV曲线进行分析，确定了两个组分的质量和半径，M1 = 0.34±0.02 M⊙，R1 = 0.69±0.01 R⊙，M2 = 1.06±0.04 M⊙，R2 = 1.16±0.02 R⊙。我们的结果表明，V864 Mon是wuma恒星的W亚型，具有时变的光斑活动。质量-光度图和质量-半径图的位置表明，副星属于主序区，而较热的主星位于末代主序区之外。
{"title":"Photometric and spectroscopic properties of the eclipsing system V864 Monocerotis","authors":"Jang-Ho Park, Jae Woo Lee, Kyeongsoo Hong","doi":"10.1093/pasj/psad061","DOIUrl":"https://doi.org/10.1093/pasj/psad061","url":null,"abstract":"Abstract We present the orbital period variability and evolutionary status of the W UMa-type binary system V864 Mon from accurately measured fundamental parameters. New BV photometric observations of this system were performed in 2019 January and 2022 January, and the first high-resolution spectroscopic observations were carried out on three nights between 2019 January and March. A total of 29 times of minimum light were collected to examine the behavior of the orbital period. Our analysis of these timings indicates a continuous period increase at a rate of +2.62 × 10−7 d yr−1 over the past 20 years, which can be interpreted as a mass transfer from the less massive primary to the secondary component with a rate of 1.22 × 10−7 M⊙ yr−1. We measured the radial velocities (RVs) for both components, and determined the effective temperature and projected rotational velocity of the more massive secondary star to be Teff,2 = 5450 ± 94 K and v2sin i = 192 ± 40 km s−1, respectively, from the comparison of the observed spectrum at the primary minimum and the theoretical models. The individual masses and radii of both components were determined from a simultaneous analysis of the light and RV curves, which are M1 = 0.34 ± 0.02 M⊙, R1 = 0.69 ± 0.01 R⊙, and M2 = 1.06 ± 0.04 M⊙, R2 = 1.16 ± 0.02 R⊙, respectively. Our results indicate that V864 Mon is a W-subtype of W UMa stars with time-varying spot activity. The positions in the mass-luminosity and mass-radius diagrams indicate that the secondary star belongs to the main-sequence region, while the hotter primary is located beyond the terminal-age main sequence.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394468","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 We systematically analyzed Swift/XRT X-ray data of gamma-ray-emitting radio galaxies (RGs) to study the origin of X-ray radiation. We studied the short-duration variability of spectra by using Swift/XRT data for 20 RGs. We found that gamma-ray-emitting RGs with a higher gamma-ray-to-X-ray flux ratio show a strong harder-when-brighter behavior. In addition, gamma-ray-emitting RGs with soft gamma-ray spectral index tend to have a hard X-ray spectral index and vice versa. Based on these properties, we imply a trend that gamma-ray-emitting RGs could be roughly classified into three types of X-ray emission: jet-dominated type, disk/corona-dominated type, and intermediate type. This classification is quite consistent with the optical and radio classification of RGs. In addition, we also discuss this result in terms of the Eddington luminosity ratio. These interpretations should be confirmed using larger samples of RGs in the future.
{"title":"Statistical X-ray analysis of gamma-ray-emitting radio galaxies","authors":"Hiroto Matake, Yasushi Fukazawa","doi":"10.1093/pasj/psad060","DOIUrl":"https://doi.org/10.1093/pasj/psad060","url":null,"abstract":"Abstract We systematically analyzed Swift/XRT X-ray data of gamma-ray-emitting radio galaxies (RGs) to study the origin of X-ray radiation. We studied the short-duration variability of spectra by using Swift/XRT data for 20 RGs. We found that gamma-ray-emitting RGs with a higher gamma-ray-to-X-ray flux ratio show a strong harder-when-brighter behavior. In addition, gamma-ray-emitting RGs with soft gamma-ray spectral index tend to have a hard X-ray spectral index and vice versa. Based on these properties, we imply a trend that gamma-ray-emitting RGs could be roughly classified into three types of X-ray emission: jet-dominated type, disk/corona-dominated type, and intermediate type. This classification is quite consistent with the optical and radio classification of RGs. In addition, we also discuss this result in terms of the Eddington luminosity ratio. These interpretations should be confirmed using larger samples of RGs in the future.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394459","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}
Kazuhiro D Kanagawa, Tomohiro Ono, Munetake Momose
Abstract A planet embedded in a protoplanetary disk produces a gap by disk–planet interaction. It also generates velocity perturbation of gas, which can also be observed as deviations from the Keplerian rotation in the channel map of molecular line emission, called kinematic planetary features. These observed signatures provide clues to determine the mass of the planet. We investigated the features induced by a planet with an inclined orbit through three-dimensional hydrodynamic simulations. We found that a smaller planet, with an inclination of ∼10○–20○, can produce kinematic features as prominent as those induced by a massive coplanar planet. Despite the kinematic features being similar, the gap is shallower and narrower compared with the case in which the kinematic features are formed by a coplanar planet. We also found that the kinematic features induced by an inclined planet were fainter for rarer CO isotopologues because the velocity perturbation is weaker at the position closer to the midplane, which was different in the case with a coplanar massive planet. This dependence on the isotopologues is distinguished if the planet has an inclined orbit. We discussed two observed kinematic features in the disk of HD 163296. We concluded that the kink observed at 220 au can be induced by an inclined planet, while the kink at 67 au is consistent to that induced by a coplanar planet.
{"title":"Kinematic signatures of a low-mass planet with a moderately inclined orbit in a protoplanetary disk","authors":"Kazuhiro D Kanagawa, Tomohiro Ono, Munetake Momose","doi":"10.1093/pasj/psad059","DOIUrl":"https://doi.org/10.1093/pasj/psad059","url":null,"abstract":"Abstract A planet embedded in a protoplanetary disk produces a gap by disk–planet interaction. It also generates velocity perturbation of gas, which can also be observed as deviations from the Keplerian rotation in the channel map of molecular line emission, called kinematic planetary features. These observed signatures provide clues to determine the mass of the planet. We investigated the features induced by a planet with an inclined orbit through three-dimensional hydrodynamic simulations. We found that a smaller planet, with an inclination of ∼10○–20○, can produce kinematic features as prominent as those induced by a massive coplanar planet. Despite the kinematic features being similar, the gap is shallower and narrower compared with the case in which the kinematic features are formed by a coplanar planet. We also found that the kinematic features induced by an inclined planet were fainter for rarer CO isotopologues because the velocity perturbation is weaker at the position closer to the midplane, which was different in the case with a coplanar massive planet. This dependence on the isotopologues is distinguished if the planet has an inclined orbit. We discussed two observed kinematic features in the disk of HD 163296. We concluded that the kink observed at 220 au can be induced by an inclined planet, while the kink at 67 au is consistent to that induced by a coplanar planet.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135552843","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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