arXiv - PHYS - High Energy Astrophysical Phenomena最新文献_第4页

From coasting to energy-conserving: new self-similar solutions to the interaction phase of strong explosions 从滑行到能量守恒：强爆炸相互作用阶段的新自相似解

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-16 DOI: arxiv-2409.10600

Eric R. Coughlin

{"title":"From coasting to energy-conserving: new self-similar solutions to the interaction phase of strong explosions","authors":"Eric R. Coughlin","doi":"arxiv-2409.10600","DOIUrl":"https://doi.org/arxiv-2409.10600","url":null,"abstract":"Astrophysical explosions that contain dense and ram-pressure-dominated ejecta\u0000evolve through an interaction phase, during which a forward shock (FS), contact\u0000discontinuity (CD), and reverse shock (RS) form and expand with time. We\u0000describe new self-similar solutions that apply to this phase and are most\u0000accurate in the limit that the ejecta density is large compared to the ambient\u0000density. These solutions predict that the FS, CD, and RS expand at different\u0000rates in time and not as single temporal power-laws, are valid for explosions\u0000driven by steady winds and homologously expanding ejecta, and exist when the\u0000ambient density profile is a power-law with power-law index shallower than\u0000$sim 3$ (specifically when the FS does not accelerate). We find excellent\u0000agreement between the predictions of these solutions and hydrodynamical\u0000simulations, both for the temporal behavior of the discontinuities and for the\u0000variation of the fluid quantities. The self-similar solutions are applicable to\u0000a wide range of astrophysical phenomena and -- although the details are\u0000described in future work -- can be generalized to incorporate relativistic\u0000speeds with arbitrary Lorentz factors. We suggest that these solutions\u0000accurately interpolate between the initial ``coasting'' phase of the explosion\u0000and the later, energy-conserving phase (or, if the ejecta is homologous and the\u0000density profile is sufficiently steep, the self-similar phase described in\u0000Chevalier 1982),","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260108","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

Quasi-periodic $γ$-ray modulations in the blazars PKS 2155-83 and PKS 2255-282 PKS 2155-83 和 PKS 2255-282 中的准周期性 $γ 射线调制

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-16 DOI: arxiv-2409.10622

M. A. Hashad, Amr A. El-Zant, Y. Abdou, H. M. Badran

{"title":"Quasi-periodic $γ$-ray modulations in the blazars PKS 2155-83 and PKS 2255-282","authors":"M. A. Hashad, Amr A. El-Zant, Y. Abdou, H. M. Badran","doi":"arxiv-2409.10622","DOIUrl":"https://doi.org/arxiv-2409.10622","url":null,"abstract":"While there has been an increase in interest in the possibility of\u0000quasi-periodic oscillations (QPOs) in blazars, the search has hitherto been\u0000restricted to sources with well-sampled light curves. Objects with light curves\u0000that include gaps have been, to our knowledge, overlooked. Here, we study two\u0000such curves, which have the interesting feature of pertaining to relatively\u0000high redshift blazars -- FSRQs, PKS 2155-83 and PKS 2255-282 -- observed by\u0000Fermi-LAT. Their redshifts border the 'cosmic noon' era of galaxy formation and\u0000merging, and their light curves exhibit a distinctive pattern of repetitive\u0000high and low (gap dominant) states for $15.6$ years. To accommodate for the\u0000gaps in the curves, data is integrated over extended time intervals of 1 month\u0000and 2 months. The resulting curves were also examined using methods suitable\u0000for sparsely sampled data. This investigation of PKS 2155-83 and PKS 2255-282\u0000suggests QPOs with periods of $4.69pm0.79$ yr ($3sigma$) and $6.82pm2.25$ yr\u0000($2.8sigma$), respectively. The flux PDFs of the blazars, along with the\u0000correlation between their flux and spectral index, were also analyzed. Given\u0000the epochs the objects are observed, the plausibility of a binary black hole\u0000scenario as an origin of the apparent periodicity was examined. We estimated\u0000the prospective parameters of such a system using a simple geometric model. The\u0000total masses were estimated, and found to be consistent, in principle, with\u0000independent (dynamical) measurements of the central black hole masses in the\u0000two host galaxies.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260106","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

A growing braking index and spin-down swings for the pulsar PSR B0540-69 脉冲星 PSR B0540-69 不断增长的制动指数和自旋下降摆动

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-16 DOI: arxiv-2409.10759

Cristóbal M. Espinoza, Lucien Kuiper, Wynn C. G. Ho, Danai Antonopoulou, Zaven Arzoumanian, Alice K. Harding, Paul S. Ray, George Younes

引用次数: 0

Investigating the Potential of LS 5039 as a Triple System Using Fermi-LAT Data 利用费米-LAT 数据研究 LS 5039 作为三重系统的潜力

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-16 DOI: arxiv-2409.09908

Lujun Zeng, Mengqing Zhang, Chongyang Ren, Pengfei Zhang, Jingzhi Yan

{"title":"Investigating the Potential of LS 5039 as a Triple System Using Fermi-LAT Data","authors":"Lujun Zeng, Mengqing Zhang, Chongyang Ren, Pengfei Zhang, Jingzhi Yan","doi":"arxiv-2409.09908","DOIUrl":"https://doi.org/arxiv-2409.09908","url":null,"abstract":"LS 5039 is one of a handful of $gamma$-ray binary systems in the Milky Way,\u0000comprising a pulsar and a massive O-type companion star with an orbital period\u0000of 3.9 day. Recently, we conducted a data analysis using approximately 16 year\u0000of Fermi-LAT observations, spanning from 2008 August 4 to 2024 July 8. In our\u0000timing analysis, we discovered two new periodic signals with frequencies higher\u0000and lower than the known orbital period. The higher-frequency signal has a\u0000period of 3.63819 day with a 7.1$sigma$ confidence level, while the\u0000lower-frequency signal has a period of 4.21654 day with a 6.3$sigma$\u0000confidence level. Additionally, in data from the High Energy Stereoscopic\u0000System of Cherenkov Telescopes, two potential signals with periods similar to\u0000the two newly discovered ones. Considering that these two signals fall within\u0000the same frequency interval as the orbital period, we suggest the possibility\u0000of a third body orbiting the barycenter of the LS 5039 binary system, with the\u0000new periodic signals arising from specific frequency combinations of the two\u0000orbital periods.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260151","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

X-ray reverberation as an explanation for UV/optical variability in nearby Seyferts 以 X 射线混响解释附近赛弗的紫外线/光学变异性

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-16 DOI: arxiv-2409.10417

M. Papoutsis, I. E. Papadakis, C. Panagiotou, M. Dovčiak, E. Kammoun

{"title":"X-ray reverberation as an explanation for UV/optical variability in nearby Seyferts","authors":"M. Papoutsis, I. E. Papadakis, C. Panagiotou, M. Dovčiak, E. Kammoun","doi":"arxiv-2409.10417","DOIUrl":"https://doi.org/arxiv-2409.10417","url":null,"abstract":"Active galactic nuclei (AGNs) are known to be variable across all\u0000wavelengths. Significant observational efforts have been invested in the last\u0000decade in studying their ultraviolet (UV) and optical variability. Long and\u0000densely sampled, multi-wavelength monitoring campaigns of numerous Seyfert\u0000galaxies have been conducted with the aim of determining the X-ray/UV/optical\u0000continuum time lags. Time-lag studies can be used to constrain theoretical\u0000models. The observed time lags can be explained by thermal reprocessing of the\u0000X-rays illuminating the accretion disc (known as the X-ray reverberation\u0000model). However, the observed light curves contain more information that can be\u0000used to further constrain physical models. Our primary objective is to\u0000investigate whether, in addition to time lags, the X-ray reverberation model\u0000can also explain the UV/optical variability amplitude of nearby Seyferts. To do\u0000this, we measured the excess variance of four sources (namely Mrk 509, NGC\u00004151, NGC 2617, and Mrk 142) as a function of wavelength using data from\u0000archival long, multi-wavelength campaigns with Swift, and ground-based\u0000telescopes. We also computed the model excess variance in the case of the X-ray\u0000reverberation model by determining the disc's transfer function and assuming a\u0000bending power law for the X-ray power spectrum. We tested the validity of the\u0000model by comparing the measured and model variances for a range of accretion\u0000rates and X-ray source heights. We conclude that the X-ray thermal\u0000reverberation model can fit both the continuum, UV/optical time lags, as well\u0000as the variance in these AGNs, for the same physical parameters. Our results\u0000suggest that the accretion disc is constant and that all the observed\u0000UV/optical variations, on timescales of days and up to a few weeks, can be\u0000fully explained by the variable X-rays as they illuminate the accretion disc.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260148","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

How Long Will the Quasar UV/Optical Flickering Be Damped? II. the Observational Test 类星体的紫外线/光学闪烁会被阻尼多久？二、观测检验

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-15 DOI: arxiv-2409.09637

Guowei RenXMU, Shuying ZhouXMU, Mouyuan SunXMU, Yongquan XueUSTC

{"title":"How Long Will the Quasar UV/Optical Flickering Be Damped? II. the Observational Test","authors":"Guowei RenXMU, Shuying ZhouXMU, Mouyuan SunXMU, Yongquan XueUSTC","doi":"arxiv-2409.09637","DOIUrl":"https://doi.org/arxiv-2409.09637","url":null,"abstract":"The characteristic timescale at which the variability of active galactic\u0000nuclei (AGNs) turns from red noise to white noise can probe the accretion\u0000physics around supermassive black holes (SMBHs). A number of works have studied\u0000the characteristic timescale of quasars and obtained quite different scaling\u0000relations between the timescale and quasar physical properties. One possible\u0000reason for the discrepancies is that the characteristic timescale can be easily\u0000underestimated if the light curves are not long enough. In this work, we\u0000construct well-defined AGN samples to observationally test the relationships\u0000between the characteristic timescale and AGN properties obtained by previous\u0000works. Our samples eliminate the effects of insufficient light-curve lengths.\u0000We confirm that the timescale predictions citep{Zhou2024} of the Corona Heated\u0000Accretion disk Reprocessing model are consistent with our timescale\u0000measurements. The timescale predictions by empirically relations\u0000citep[e.g.,][]{Kelly2009} are systematically smaller than our measured ones.\u0000Our results provide further evidence that AGN variability is driven by thermal\u0000fluctuations in SMBH accretion disks. Future flagship time-domain surveys can\u0000critically test our conclusions and reveal the physical nature of AGN\u0000variability.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260027","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

Binary Stars Approaching Supermassive Black Holes: Tidal Break-up, Double Stellar Disruptions and Stellar Collision 接近超大质量黑洞的双星：潮汐破裂、双恒星扰动和恒星碰撞

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-15 DOI: arxiv-2409.09597

Fangyuan Yu, Dong Lai

{"title":"Binary Stars Approaching Supermassive Black Holes: Tidal Break-up, Double Stellar Disruptions and Stellar Collision","authors":"Fangyuan Yu, Dong Lai","doi":"arxiv-2409.09597","DOIUrl":"https://doi.org/arxiv-2409.09597","url":null,"abstract":"In galactic centers, stars and binaries can be injected into\u0000low-angular-momentum orbits, resulting in close encounters with the central\u0000supermassive black hole (SMBH). We use $N$-body simulations to study such\u0000encounters systematically under a wide range of conditions. Depending on the\u0000system parameters (such as $beta_b$, the ratio of binary tidal radius to\u0000pericenter distance $r_p$ to the SMBH, and the compactness of the binary), such\u0000close encounters can lead to the break-up of the binary, disruptions of both\u0000stars and collision between the stars. Binary break-up produces a\u0000hyper-velocity star and a bound star around the SMBH; the peak value of the\u0000orbital binding energy depends weakly on $beta_b$. When $r_p$ is comparable to\u0000the stellar tidal radius, sequential disruptions of the stars occur within a\u0000time interval much shorter than the initial binary orbital period, potentially\u0000exhibiting distinct double TDE features. Stellar collisions occur for a range\u0000of $beta_b$'s, with a few to 10's percent probabilities (depending on the\u0000compactness of the binary). In gentle encounters ($beta_blesssim 1$), stellar\u0000collisions occur after the pericenter passage, and the merger remnants are\u0000typically ejected from the SMBH at a small velocity. In deep encounters\u0000($beta_bgtrsim 1$), collisions occur near the pericenter, and the merger\u0000remnants are typically bound to the SMBH. We suggest that stellar collisions\u0000induced by binary-SMBH encounters may produce exotic stars in galactic centers,\u0000trigger accretion flares onto the SMBH due to the mass loss, and result in\u0000bound merger remnants causing repeated partial TDEs.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260152","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

The Interplay between the Disk and Corona of the Changing-look Active Galactic Nucleus 1ES 1927+654 变化外观的活动星系核 1ES 1927+654 的星盘和日冕之间的相互作用

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-14 DOI: arxiv-2409.09264

Ruancun LiKavli Institute for Astronomy and Astrophysics, Peking University, Claudio Ricci, Luis C. Ho, Benny Trakhtenbrot, Erin Kara, Megan Masterson, Iair Arcavi

{"title":"The Interplay between the Disk and Corona of the Changing-look Active Galactic Nucleus 1ES 1927+654","authors":"Ruancun LiKavli Institute for Astronomy and Astrophysics, Peking University, Claudio Ricci, Luis C. Ho, Benny Trakhtenbrot, Erin Kara, Megan Masterson, Iair Arcavi","doi":"arxiv-2409.09264","DOIUrl":"https://doi.org/arxiv-2409.09264","url":null,"abstract":"Time-domain studies of active galactic nuclei (AGNs) offer a powerful tool\u0000for understanding black hole accretion physics. Prior to the optical outburst\u0000on 23 December 2017, 1ES 1927+654 was classified as a \"true\" type~2 AGN, an\u0000unobscured source intrinsically devoid of broad-line emission in polarized\u0000spectra. Through our three-year monitoring campaign spanning X-ray to\u0000ultraviolet/optical wavelengths, we analyze the post-outburst evolution of the\u0000spectral energy distribution (SED) of 1ES 1927+654. Examination of the\u0000intrinsic SED and subsequent modeling using different models reveal that the\u0000post-outburst spectrum is best described by a combination of a disk, blackbody,\u0000and corona components. We detect systematic SED variability and identify four\u0000distinct stages in the evolution of these components. During the event the\u0000accretion rate is typically above the Eddington limit. The correlation between\u0000ultraviolet luminosity and optical to X-ray slope ($alpha_mathrm{OX}$)\u0000resembles that seen in previous studies of type 1 AGNs, yet exhibits two\u0000distinct branches with opposite slopes. The optical bolometric correction\u0000factor ($kappa_{5100}$) is $sim 10$ times higher than typical AGNs, again\u0000displaying two distinct branches. Correlations among the corona optical depth,\u0000disk surface density, and $alpha_mathrm{OX}$ provide compelling evidence of a\u0000disk-corona connection. The X-ray corona showcases systematic variation in the\u0000compactness-temperature plot. Between 200 and 650 days, the corona is\u0000\"hotter-when-brighter\", whereas after 650 days, it becomes\u0000\"cooler-when-brighter\". This bimodal behavior, in conjunction with the\u0000bifurcated branches of $alpha_mathrm{OX}$ and $kappa_{5100}$, offers strong\u0000evidence of a transition from a slim disk to thin disk $sim 650$ days after\u0000the outburst.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269857","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

Metamorphosis of Positronium Moving Across a Magnetic Field 穿越磁场的正电子的变形

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-14 DOI: arxiv-2409.09496

B. O. Kerbikov, A. A. Simovonian

引用次数: 0

A Two-zone Accretion Disk in the Changing-look Active Galactic Nucleus 1ES 1927+654: Physical Implications for Tidal Disruption Events and Super-Eddington Accretion 变貌活动星系核 1ES 1927+654 中的双区吸积盘：潮汐扰动事件和超爱丁顿吸积的物理意义

arXiv - PHYS - High Energy Astrophysical Phenomena Pub Date : 2024-09-14 DOI: arxiv-2409.09265

Ruancun LiKavli Institute for Astronomy and Astrophysics, Peking University, Luis C. Ho, Claudio Ricci, Benny Trakhtenbrot

{"title":"A Two-zone Accretion Disk in the Changing-look Active Galactic Nucleus 1ES 1927+654: Physical Implications for Tidal Disruption Events and Super-Eddington Accretion","authors":"Ruancun LiKavli Institute for Astronomy and Astrophysics, Peking University, Luis C. Ho, Claudio Ricci, Benny Trakhtenbrot","doi":"arxiv-2409.09265","DOIUrl":"https://doi.org/arxiv-2409.09265","url":null,"abstract":"The properties of slim accretion disks, while crucial for our understanding\u0000of black hole growth, have yet to be studied extensively observationally. We\u0000analyze the multi-epoch broad-band spectral energy distribution of the\u0000changing-look active galactic nucleus 1ES 1927+654 to derive the properties of\u0000its complex, time-dependent accretion flow. The accretion rate decays as\u0000$dot{M} propto t^{-1.53}$, consistent with the tidal disruption of a $1.1,\u0000M_odot$ star. Three components contribute to the spectral energy distribution:\u0000a central overheated zone resembling a slim disk, an outer truncated thin disk,\u0000and a hot corona. Photon trapping in the slim disk triggered by the high\u0000initial $dot{M}$ was characterized by a low radiation efficiency ($3%$),\u0000which later more than doubled ($8%$) after $dot{M}$ dropped sufficiently low\u0000for the disk to transition to a geometrically thin state. The blackbody\u0000temperature profile $T propto R^{-0.60}$ for the inner overheated zone matches\u0000the theoretical expectations of a slim disk, while the effective temperature\u0000profile of $T propto R^{-0.69}$ for the outer zone is consistent with the\u0000predictions of a thin disk. Both profiles flatten toward the inner boundary of\u0000the disk as a result of Compton cooling in the corona. Our work presents\u0000compelling observational evidence for the existence of slim accretion disks and\u0000elucidates the key parameters governing their behavior, paving the way for\u0000further exploration in this area.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260154","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