IF 2.5

Galaxies Pub Date : 2023-12-29 DOI: 10.3390/galaxies12010002

Wenjing Dong, Qian Dong, Yonggang Zheng

引用次数: 0

Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers 通过大质量/矮圆盘星系合并形成过渡性 cE/UCD 星系

IF 2.5

Galaxies Pub Date : 2023-12-25 DOI: 10.3390/galaxies12010001

Alexander V. Khoperskov, S. Khrapov, Danila S. Sirotin

{"title":"Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers","authors":"Alexander V. Khoperskov, S. Khrapov, Danila S. Sirotin","doi":"10.3390/galaxies12010001","DOIUrl":"https://doi.org/10.3390/galaxies12010001","url":null,"abstract":"The dynamics of the merger of a dwarf disc galaxy with a massive spiral galaxy of the Milky Way type were studied in detail. The remnant of such interaction after numerous crossings of the satellite through the disc of the main galaxy was a compact stellar core, the characteristics of which were close to small compact elliptical galaxies (cEs) or large ultra-compact dwarfs (UCDs). Such transitional cE/UCD objects with an effective radius of 100–200 pc arise as a result of stripping the outer layers of the stellar core during the destruction of a dwarf disc galaxy. Numerical models of the satellite before interaction included baryonic matter (stars and gas) and dark mass. We used N-body to describe the dynamics of stars and dark matter, and we used smoothed-particle hydrodynamics to model the gas components of both galaxies. The direct method of calculating the gravitational force between all particles provided a qualitative resolution of spatial structures up to 10 pc. The dwarf galaxy fell onto the gas and stellar discs of the main galaxy almost along a radial trajectory with a large eccentricity. This ensured that the dwarf crossed the disc of the main galaxy at each pericentric approach over a time interval of more than 9 billion years. We varied the gas mass and the initial orbital characteristics of the satellite over a wide range, studying the features of mass loss in the core. The presence of the initial gas component in a dwarf galaxy significantly affects the nature of the formation and evolution of the compact stellar core. The gas-rich satellite gives birth to a more compact elliptical galaxy compared to the merging gas-free dwarf galaxy. The initial gas content in the satellite also affects the internal rotation in the stripped nucleus. The simulated cE/UCD galaxies contained very little gas and dark matter at the end of their evolution.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":"11 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139158590","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

S0 Galaxies: Outer Gas Accretion through Tidal Interaction and Minor Merging S0 星系：通过潮汐相互作用和小合并实现外层气体增殖

IF 2.5

Galaxies Pub Date : 2023-12-08 DOI: 10.3390/galaxies11060119

Olga Sil’chenko, A. Moiseev, Alexandrina Smirnova, Roman Uklein

引用次数: 0

Testing a Lepto-Hadronic Two-Zone Model with Extreme High-Synchrotron Peaked BL Lacs and Track-like High-Energy Neutrinos 用极端高同步辐射峰值 BL Lacs 和轨迹样高能中微子测试跃迁-超高速双区模型

IF 2.5

Galaxies Pub Date : 2023-12-06 DOI: 10.3390/galaxies11060117

E. Aguilar-Ruiz, A. Galván-Gámez, N. Fraija

{"title":"Testing a Lepto-Hadronic Two-Zone Model with Extreme High-Synchrotron Peaked BL Lacs and Track-like High-Energy Neutrinos","authors":"E. Aguilar-Ruiz, A. Galván-Gámez, N. Fraija","doi":"10.3390/galaxies11060117","DOIUrl":"https://doi.org/10.3390/galaxies11060117","url":null,"abstract":"Numerous studies suggest that high-energy (HE) neutrinos and ultra-high-energy (UHE) cosmic rays could originate from extremely high-synchrotron peaked (EHSP) BL Lacs, which have been identified as effective particle accelerators. Due to the discovery of HE-neutrinos by the IceCube telescope, these hypotheses may shortly have the opportunity to be tested. In this work, we use a two-zone leptohadronic model to explain the spatial coincidence of three EHSP BL Lac: 1RXS J09462.5+010459, 1ES 1101-232, and 3HSP J095507.9+355101 with the arrival of track-like neutrinos. Our results for 1RXS J09462.5+010459 and 1ES 1101-232 indicate that the model accurately describes the electromagnetic emission and neutrino events without increasing the fluxes in the measured bands. In addition, the X-ray flaring state of 3HSP J095507.9+355101 can be explained by our model, but the measured ultraviolet flux during the neutrino arrival time window cannot be explained. For all cases, the broadband emission and neutrino arrival are better described by hard proton distributions ≈1.5. Finally, the proton luminosity required to explain the neutrino fluxes is slightly higher than the Eddington limit with a photopion efficiency of ≈0.1 for non-flaring state cases. On the other hand, for the flaring state of 3HSP J095507.9+355101, the proton luminosity must be higher than the Eddington limit at least by one order of magnitude, even if the photopion efficiency reaches unity.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":"41 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138597497","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

Ionizing Spotlight of Active Galactic Nucleus 活动星系核的电离聚光灯

IF 2.5

Galaxies Pub Date : 2023-12-03 DOI: 10.3390/galaxies11060118

A. Moiseev, A. Smirnova

引用次数: 0

On the Maximum Energy Release from Formation of Static Compact Objects 论静态紧凑物体形成过程中的最大能量释放

IF 2.5

Galaxies Pub Date : 2023-11-21 DOI: 10.3390/galaxies11060116

Abhas Mitra, Krishna Kumar Singh

引用次数: 0

Holographic Quantum-Foam Blurring Is Consistent with Observations of Gamma-Ray Burst GRB221009A 全息量子泡沫模糊与伽马射线暴 GRB221009A 的观测结果一致

IF 2.5

Galaxies Pub Date : 2023-11-17 DOI: 10.3390/galaxies11060115

Eric Steinbring

{"title":"Holographic Quantum-Foam Blurring Is Consistent with Observations of Gamma-Ray Burst GRB221009A","authors":"Eric Steinbring","doi":"10.3390/galaxies11060115","DOIUrl":"https://doi.org/10.3390/galaxies11060115","url":null,"abstract":"Gamma-ray burst GRB221009A was of unprecedented brightness in the γ-rays and X-rays through to the far ultraviolet, allowing for identification within a host galaxy at redshift z=0.151 by multiple space and ground-based optical/near-infrared telescopes and enabling a first association—via cosmic-ray air-shower events—with a photon of 251 TeV. That is in direct tension with a potentially observable phenomenon of quantum gravity (QG), where spacetime “foaminess” accumulates in wavefronts propagating cosmological distances, and at high-enough energy could render distant yet bright pointlike objects invisible, by effectively spreading their photons out over the whole sky. But this effect would not result in photon loss, so it remains distinct from any absorption by extragalactic background light. A simple multiwavelength average of foam-induced blurring is described, analogous to atmospheric seeing from the ground. When scaled within the fields of view for the Fermi and Swift instruments, it fits all z≤5 GRB angular-resolution data of 10 MeV or any lesser peak energy and can still be consistent with the highest-energy localization of GRB221009A: a limiting bound of about 1 degree is in agreement with a holographic QG-favored formulation.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":"25 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266481","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

Quasiperiodic Oscillations and Dynamics of Test Particles around Regular-Kiselev Black Holes 正基塞列夫黑洞周围测试粒子的准周期振荡和动力学特性

IF 2.5

Galaxies Pub Date : 2023-11-16 DOI: 10.3390/galaxies11060113

J. Rayimbaev, N. Juraeva, Malika Khudoyberdiyeva, A. Abdujabbarov, Mardon Abdullaev

{"title":"Quasiperiodic Oscillations and Dynamics of Test Particles around Regular-Kiselev Black Holes","authors":"J. Rayimbaev, N. Juraeva, Malika Khudoyberdiyeva, A. Abdujabbarov, Mardon Abdullaev","doi":"10.3390/galaxies11060113","DOIUrl":"https://doi.org/10.3390/galaxies11060113","url":null,"abstract":"Testing gravity theories combining (massive and massless) scalar & electrodynamic fields become the most important issue in relativistic astrophysics using data from, black hole observations. In the present work, we first show a spherically symmetric black hole solution in general relativity coupling to generic-type nonlinear electrodynamics (NED) together with the quintessential field. We also obtain possible values for the parameters of the quintessential field and NED charge in the black hole environment for different values of degree of nonlinearity. Also, event horizon properties and scalar invariants of the black hole spacetime are studied. We investigate the equatorial motion of test particles around the regular-Kiselev black holes and study the combined effects of quintessential field and the NED charge of the black hole on particle angular momentum together with its energy at their circular orbits as well as their innermost circular stable orbits (ISCOs) and compared the obtained results with Reissner-Nordström black hole (RN BH) case. Moreover, we study particle oscillations along the orbits above than ISCO and applications to quasiperiodic oscillations (QPOs) where we obtain constrain values for the quintessential parameter and black hole mass charge parameters using observational QPO data from microquasars.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":"C-34 11","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139267920","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

Simulated Radio and Neutrino Imaging of a Microquasar 微类星体的模拟射电和中微子成像

Galaxies Pub Date : 2023-11-09 DOI: 10.3390/galaxies11060110

Theodoros Smponias

引用次数: 0

Optimization of Quantum Noise in Space Gravitational-Wave Antenna DECIGO with Optical-Spring Quantum Locking Considering Mixture of Vacuum Fluctuations in Homodyne Detection 考虑空差探测中真空波动混合的空间引力波天线DECIGO中量子噪声的优化

Galaxies Pub Date : 2023-11-09 DOI: 10.3390/galaxies11060111

Kenji Tsuji, Tomohiro Ishikawa, Kentaro Komori, Koji Nagano, Yutaro Enomoto, Yuta Michimura, Kurumi Umemura, Ryuma Shimizu, Bin Wu, Shoki Iwaguchi, Yuki Kawasaki, Akira Furusawa, Seiji Kawamura

{"title":"Optimization of Quantum Noise in Space Gravitational-Wave Antenna DECIGO with Optical-Spring Quantum Locking Considering Mixture of Vacuum Fluctuations in Homodyne Detection","authors":"Kenji Tsuji, Tomohiro Ishikawa, Kentaro Komori, Koji Nagano, Yutaro Enomoto, Yuta Michimura, Kurumi Umemura, Ryuma Shimizu, Bin Wu, Shoki Iwaguchi, Yuki Kawasaki, Akira Furusawa, Seiji Kawamura","doi":"10.3390/galaxies11060111","DOIUrl":"https://doi.org/10.3390/galaxies11060111","url":null,"abstract":"Quantum locking using optical spring and homodyne detection has been devised to reduce the quantum noise that limits the sensitivity of the DECIGO, a space-based gravitational-wave antenna in the frequency band around 0.1 Hz for the detection of primordial gravitational waves. The reduction in the upper limit of energy density ΩGW from 2×10−15 to 1×10−16, as inferred from recent observations, necessitates improved sensitivity in the DECIGO to meet its primary science goals. To accurately evaluate the effectiveness of this method, this paper considers a detection mechanism that takes into account the influence of vacuum fluctuations on homodyne detection. In addition, an advanced signal processing method is devised to efficiently utilize signals from each photodetector, and design parameters for this configuration are optimized for the quantum noise. Our results show that this method is effective in reducing quantum noise, despite the detrimental impact of vacuum fluctuations on its sensitivity.","PeriodicalId":37570,"journal":{"name":"Galaxies","volume":" 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135290991","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

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