Galaxies最新文献_第10页

On the Periodic Orbits of the Perturbed Two- and Three-Body Problems 关于摄动二、三体问题的周期轨道

IF 2.5

Galaxies Pub Date : 2023-04-18 DOI: 10.3390/galaxies11020058

Elbaz I. Abouelmagd, J. L. Guirao, J. Llibre

引用次数: 0

The Effect of the LMC on the Milky Way System LMC对银河系的影响

IF 2.5

Galaxies Pub Date : 2023-04-18 DOI: 10.3390/galaxies11020059

E. Vasiliev

引用次数: 4

Revealing the Binarity of HD 36030—One of the Hottest Flare Stars 揭示HD 36030的双星性——最热的耀斑之一

IF 2.5

Galaxies Pub Date : 2023-04-12 DOI: 10.3390/galaxies11020055

O. Maryeva, P. Németh, S. Karpov

引用次数: 0

BCD Spectrophotometry and Rotation of Active B-Type Stars: Theory and Observations BCD分光光度法与活跃b型星的自转:理论与观测

IF 2.5

Galaxies Pub Date : 2023-04-10 DOI: 10.3390/galaxies11020054

J. Zorec

引用次数: 0

Intermediate-Mass Black Holes: The Essential Population to Explore the Unified Model for Accretion and Ejection Processes 中等质量黑洞:探索吸积和抛射过程统一模型的必要群体

IF 2.5

Galaxies Pub Date : 2023-04-06 DOI: 10.3390/galaxies11020053

Xiaolong Yang, J. Yang

{"title":"Intermediate-Mass Black Holes: The Essential Population to Explore the Unified Model for Accretion and Ejection Processes","authors":"Xiaolong Yang, J. Yang","doi":"10.3390/galaxies11020053","DOIUrl":"https://doi.org/10.3390/galaxies11020053","url":null,"abstract":"We study radio and X-ray emissions from intermediate-mass black holes (IMBHs) and explore the unified model for accretion and ejection processes. The radio band survey of IMBH (candidate) hosted galaxies indicates that only a small fraction (∼0.6%) of them are radio-band active. In addition, very long baseline interferometry observations reveal parsec-scale radio emission of IMBHs, further resulting in a lower fraction of actively ejecting objects (radio emission is produced by IMBHs other than hosts), which is consistent with a long quiescent state in the evolution cycle of IMBHs. Most (75%, i.e., 3 out of 4 samples according to a recent mini-survey) of the radio-emitting IMBHs are associated with radio relics and there is also evidence of dual radio blobs from episodic ejecting phases. Taking the radio emission and the corresponding core X-ray emission of IMBH, we confirm a universal fundamental plane relation (FMP) of black hole activity. Furthermore, state transitions can be inferred by comparing a few cases in XRBs and IMBHs in FMP, i.e., both radio luminosity and emission regions evolve along these state transitions. These signatures and evidence suggest an analogy among all kinds of accretion systems which span from stellar mass to supermassive black holes, hinting at unified accretion and ejection physics. To validate the unified model, we explore the correlation between the scale of outflows (corresponding to ejection powers) and the masses of central engines; it shows that the largest scale of outflows LS^out follows a power-law correlation with the masses of accretors Mcore, i.e., logLS^out=(0.73±0.01)logMcore−(3.34±0.10). In conclusion, this work provides evidence to support the claim that the ejection (and accretion) process behaves as scale-invariant and their power is regulated by the masses of accretors.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47657667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Metal Content in Relativistically Jetted and Radio-Quiet Quasars in the Main Sequence Context 主序背景下相对论喷射和射电安静类星体中的金属含量

IF 2.5

Galaxies Pub Date : 2023-03-23 DOI: 10.3390/galaxies11020052

P. Marziani, S. Panda, Alice Deconto Machado, A. Olmo

{"title":"Metal Content in Relativistically Jetted and Radio-Quiet Quasars in the Main Sequence Context","authors":"P. Marziani, S. Panda, Alice Deconto Machado, A. Olmo","doi":"10.3390/galaxies11020052","DOIUrl":"https://doi.org/10.3390/galaxies11020052","url":null,"abstract":"The optical and UV properties of radio-quiet (RQ) and radio-loud (RL, relativistically “jetted”) active galactic nuclei (AGN) are known to differ markedly; however, it is still unclear what is due to a sample selection and what is associated with intrinsic differences in the inner workings of their emitting regions. Chemical composition is an important parameter related to the trends of the quasar main sequence. Recent works suggest that in addition to physical properties such as density, column density, and ionization level, strong Feii emitters require very high metal content. Little is known, however, about the chemical composition of jetted radio-loud sources. In this short note, we present a pilot analysis of the chemical composition of low-z radio-loud and radio-quiet quasars. Optical and UV spectra from ground and space were combined to allow for precise measurements of metallicity-sensitive diagnostic ratios. The comparison between radio-quiet and radio-loud was carried out for sources in the same domain of the Eigenvector 1/main sequence parameter space. Arrays of dedicated photo-ionization simulations with the input of appropriate spectral energy distributions indicate that metallicity is sub-solar for RL AGN, and slightly sub-solar or around solar for RQ AGN. The metal content of the broad line-emitting region likely reflects a similar enrichment story for both classes of AGN not involving recent circum-nuclear or nuclear starbursts.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47619749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Past and Future of East Asia to Italy: Nearly Global VLBI 从东亚到意大利的过去和未来：近乎全球的VLBI

IF 2.5

Galaxies Pub Date : 2023-03-22 DOI: 10.3390/galaxies11020049

G. Giovannini, Yuzhu Cui, K. Hada, K. -H. Yi, H. Ro, B. Sohn, M. Takamura, Salvatore Buttaccio, F. D’Ammando, M. Giroletti, Y. Hagiwara, M. Kino, E. Kravchenko, G. Maccaferri, Alexey Melnikov, K. Niinuma, M. Orienti, K. Wajima, K. Akiyama, A. Doi, D. Byun, T. Hirota, M. Honma, T. Jung, H. Kobayashi, S. Koyama, A. Melis, C. Migoni, Y. Murata, H. Nagai, S. Sawada-Satoh, M. Stagni

{"title":"The Past and Future of East Asia to Italy: Nearly Global VLBI","authors":"G. Giovannini, Yuzhu Cui, K. Hada, K. -H. Yi, H. Ro, B. Sohn, M. Takamura, Salvatore Buttaccio, F. D’Ammando, M. Giroletti, Y. Hagiwara, M. Kino, E. Kravchenko, G. Maccaferri, Alexey Melnikov, K. Niinuma, M. Orienti, K. Wajima, K. Akiyama, A. Doi, D. Byun, T. Hirota, M. Honma, T. Jung, H. Kobayashi, S. Koyama, A. Melis, C. Migoni, Y. Murata, H. Nagai, S. Sawada-Satoh, M. Stagni","doi":"10.3390/galaxies11020049","DOIUrl":"https://doi.org/10.3390/galaxies11020049","url":null,"abstract":"We present here the East Asia to Italy Nearly Global VLBI (EATING VLBI) project. How this project started and the evolution of the international collaboration between Korean, Japanese, and Italian researchers to study compact sources with VLBI observations is reported. Problems related to the synchronization of the very different arrays and technical details of the telescopes involved are presented and discussed. The relatively high observation frequency (22 and 43 GHz) and the long baselines between Italy and East Asia produced high-resolution images. We present example images to demonstrate the typical performance of the EATING VLBI array. The results attracted international researchers and the collaboration is growing, now including Chinese and Russian stations. New in progress projects are discussed and future possibilities with a larger number of telescopes and a better frequency coverage are briefly discussed herein.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43431435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Challenges of This Century in High-Density Compact Objects, High-Energy Astrophysics, and Multi-Messenger Observations: Quo Vadis? 本世纪高密度致密天体、高能天体物理学和多信使观测的挑战:现状如何?

IF 2.5

Galaxies Pub Date : 2023-03-22 DOI: 10.3390/galaxies11020048

J. G. Coelho, R. D. dos Anjos

引用次数: 0

The Formalism of Milky-Way Antimatter-Domains Evolution 银河系反物质域演化的形式主义

IF 2.5

Galaxies Pub Date : 2023-03-22 DOI: 10.3390/galaxies11020050

M. Khlopov, O. Lecian

引用次数: 1

The Interplay between Radio AGN Activity and Their Host Galaxies 射电AGN活动与宿主星系的相互作用

IF 2.5

Galaxies Pub Date : 2023-03-21 DOI: 10.3390/galaxies11020047

G. Couto, T. Storchi-Bergmann

{"title":"The Interplay between Radio AGN Activity and Their Host Galaxies","authors":"G. Couto, T. Storchi-Bergmann","doi":"10.3390/galaxies11020047","DOIUrl":"https://doi.org/10.3390/galaxies11020047","url":null,"abstract":"Radio activity in AGN (Active Galactic Nuclei) produce feedback on the host galaxy via the impact of the relativistic jets on the circumnuclear gas. Although radio jets can reach up to several times the optical radius of the host galaxy, in this review we focus on the observation of the feedback deposited locally in the central region of the host galaxies, in the form of outflows due to the jet-gas interaction. We begin by discussing how galaxy mergers and interactions are the most favored scenario for triggering radio AGN after gas accretion to the nuclear supermassive black hole and star formation enhancement in the nuclear region, observed in particular in the most luminous sources. We then discuss observational signatures of the process of jet-gas coupling, in particular the resulting outflows and their effects on the host galaxy. These include the presence of shock signatures and the detection of outflows not only along the radio jet but perpendicular to it in many sources. Although most of the studies are done via the observation of ionized gas, molecular gas is also being increasingly observed in outflow, contributing to the bulk of the mass outflow rate. Even though most radio sources present outflow kinetic powers that do not reach 1%Lbol, and thus do not seem to provide an immediate impact on the host galaxy, they act to heat the ISM gas, preventing star formation, slowing the galaxy mass build-up process and limiting the stellar mass growth, in a “maintenance mode” feedback.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49554418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1