搜索到1927篇“ SEYFERT“的相关文章
Long Term X-Ray Spectral Variations of the Seyfert-1 Galaxy Mrk 279
2024年
We present the results from a long term X-ray analysis of Mrk 279 during the period 2018–2020.We use data from multiple missions–AstroSat,NuSTAR and XMM-Newton,for the purpose.The X-ray spectrum can be modeled as a double Comptonization along with the presence of neutral Fe Kαline emission,at all epochs.We determined the source’s X-ray flux and luminosity at these different epochs.We find significant variations in the source’s flux state.We also investigate the variations in the source’s spectral components during the observation period.We find that the photon index and hence the spectral shape follow the variations only over longer time periods.We probe the correlations between fluxes of different bands and their photon indices,and found no significant correlations between the parameters.
K.AkhilaRanjeev MisraSavithri H.EzhikodeK.Jeena
A Possible X-ray Quasi-periodic Oscillation in the Narrow-line Seyfert 1 Galaxy Mrk 142
2024年
A possible quasi-periodic oscillation(QPO) at frequency 7.045 × 10^(-5) Hz is found in the narrow-line Seyfert 1galaxy Mrk 142 in the data of XMM-Newton collected on 2020 April 11.We find that the QPO signal is statistically significantly larger than the 5σ level and highly coherent with quality factor Q > 5 at the 0.3–10 keV band by using the method of the Lomb–Scargle Periodogram,the Weighted Wavelet Z-transform and the REDFIT.We analyze the data in 0.3–0.6 keV,0.6–1 keV,1–3 keV and 3–10 keV energy bands,and find obvious QPO signals at 0.3–0.6 keV and 1–3 keV bands.We then analyze the time-average spectra and time variability at the QPO frequency of 7.045 × 10^(-5) Hz,and use a model to fit them.We find that the QPO signal mainly comes from the X-ray hot corona.
Xiao-Gu ZhongJian-Cheng WangYong-Yun ChenXiao-Ling Yu
关键词:ACCRETION
平谱射电噪窄线赛弗特1型星系的红外光变性质研究
2024年
利用42个平谱射电噪窄线赛弗特1型星系(其中8个为伽马射线源)的广域红外巡天望远镜测光数据,研究其中伽马射线源和非伽马射线源的红外光变性质,以及恒星形成过程对红外光变的贡献.结果发现:(1)所有源均表现出日内光变现象;(2)相比非伽马射线源,伽马射线源平均具有更高的日内光变占空比和长期光变幅度;(3)恒星形成过程对红外波段光变的影响可以忽略.
黄伟天宁宫明毛李胜
关键词:赛弗特星系伽马射线
Study of Central Intensity Ratio of Seyfert Galaxies in Nearby Universe
2023年
We use the recently discovered simple photometric parameter Central Intensity Ratio(CIR)determined for a sample of 57 nearby(z<0.02)Seyfert galaxies to explore the central features of galaxies and their possible connection with galaxy evolution.The sample of galaxies shows strong anti-correlation between CIR and mass of their central supermassive black holes(SMBHs).The SMBH masses of ellipticals are systematically higher for a given CIR value than those for lenticulars and spirals in the sample.However,the correlation between CIR and central velocity dispersion is weak.CIR appears less influenced by the excess flux produced by the central engine in these galaxies,when compared to spectroscopic parameters like velocity dispersion and OⅣflux,and proves to be a fast and reliable tool for estimating central SMBH mass.
K.T.VinodC.BaheejaS.AswathyC.D.Ravikumar
关键词:SEYFERT
费米耀变体和射电噪类窄线赛弗特1星系之间的关系被引量:1
2023年
通过分析所收集到的费米耀变体(FSRQs和BL Lacs)和射电噪类窄线赛弗特1星系(RLNLS1s)来研究它们之间的关系.利用射电噪度参数将RLNLS1s分为低射电噪窄线赛弗特1星系(L-RLNLS1s)和高射电噪窄线赛弗特1星系(V-RLNLS1s),结果表明:(1)将logRv作为聚束效应的指标,与BL Lacs和L-RLNLS1s相比较,V-RLNLS1s具有较高的logRv,这说明V-RLNLS1s具有更高的聚束效应;(2)根据FRI和FRII的分界线(logPjet-logMBH),发现V-RLNLS1s和FRSQs大体上与BL Lacs分离,这些结果支持了FSRQs、V-RLNLS1s和FRII射电星系的统一性;(3)V-RLNLS1s遵循费米blazars中的logPjet-logLdisk相关关系,这一结果表明V-RLNLS1s喷流的形成机制与费米blazars相似;(4)大多数L-RLNLS1s、V-RLNLS1s和FSRQs具有logPjet
黄霞陈永云马力李怀珍
伽马噪窄线赛弗特1型星系TXS 1206+549的中红外波段光变性质研究
2023年
TXS 1206+549(红移z=1.344)是目前发现的最遥远的伽马噪窄线赛弗特1型星系。利用广域红外巡天探测器(Wide-field Infrared Survey Explorer,WISE)的长期测光数据,从两个方面系统研究了TXS 1206+549中红外波段的光变性质。首先,联合3种统计方法,研究了TXS 1206+549的日内光变(Intraday Variability,IDV),发现TXS 1206+549在2022年4月29日达到迄今为止所有WISE观测窗口的最亮水平,表现出非常特殊的光变过程:在约1.24天内,3.4μm和4.6μm波段分别持续变暗约1.1 mag和1.0 mag。据调研,这是第1次报道关于TXS 1206+549高置信度的中红外波段日内光变。TXS 1206+549在3.4μm和4.6μm波段的占空系数(Duty Cycle,DC)分别为27.8%和13.7%,明显低于Rakshit等人的结果,这是由于我们采用了相对保守的日内光变标准(大于3σ)。基于所有WISE观测窗口的测光数据(共21个窗口),研究了均方根-流量(rms-flux)关系,发现两者之间存在显著的线性关系。另外,发现TXS 1206+549在长时标上未表现出显著的颜色变化(即消色差),但在天量级时标上普遍表现出变亮变蓝(Bluer-When-Brighter,BWB)的趋势。结果暗示不同时标上TXS 1206+549的中红外波段光变机制不同:长期光变可能与多普勒效应相关,日内光变则可能与喷流中的激波有关。
黄伟天宁宫明毛李胜
关键词:赛弗特星系激波
The Variability of the Narrow-line Seyfert 1 Galaxies from the Pan-STARRS's View
2022年
By means of the data sets from the Pan-STARRS1 survey, we have systematically examined the relationship between the variability characteristics and the physical parameters of the largest NLS1 galaxy sample up to now.The results are summarized as follows:(1). We find significant anti-correlations between variability amplitude and absolute magnitude in g, r, i, z and y bands, which are consistent with the results in previous works.(2) The correlations between the variability amplitude in optical band and many physical parameters(e.g., λL(5100 A),black hole mass, Eddington ratio, R;and R;) are investigated. The results show the variability amplitude is significantly anti-correlated with L(5100 A), MBH, Eddington ratio and R_(4570), but positively correlated with R;.The relation could be explained by the simple standard accretion disk model.(3) We further investigate the relationship between optical variability and radio luminosity/radio-loudness. The results present weak positive correlation in g and r bands, but insignificant correlation in i, z and y bands. The large error of the approximate fraction of the host galaxy in i, z and y bands may lead to insignificant correlations.
Hong-Tao WangYan-Ping SuXue GeYong-Yun ChenXiao-Ling Yu
Jet Formation Mechanism of the Gamma-Ray-emitting Narrow-line Seyfert 1 Galaxies
2022年
We use a large sample of gamma-ray narrow-line Seyfert 1 galaxies(γ-NLS1 s) to study the jet formation mechanisms. We find that the jet power of γ-NLS1 s is lower than the maximum jet power of the Blandford–Payne(BP) mechanism. At the same time, we find that there is a significant correlation between jet power and accretion disk luminosity. Moreover, the contribution rates of the accretion to the jet power are larger than that of black hole mass to jet power. These results further suggest that the jet of γ NLS1 s is mainly produced by the BP mechanism.
Yongyun ChenQiusheng GuJunhui FanXiaoling YuDingrong XiongNan DingXiaotong GuoXue Ge
The Origin of The Soft X-Ray Excess in the Seyfert 1.5 Galaxy ESO 362-G18
2022年
We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess.The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in active galactic nuclei at present.We use the simultaneous X-ray observation data of XMM-Newton and Nu STAR on2016 September 24 to perform spectral analysis in two steps.First,we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models.Moreover,we also explore the Hybrid model,Double Reflection model and Double Warm Corona model.We find that both the Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit statistics.Second,we add the rms and covariance spectra to perform the spectral analysis with time-average spectra.The result shows that the warm corona could reproduce all of these spectra well.The hot,optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency,meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.
Xiao-Gu ZhongJian-Cheng Wang
Multicolor Optical Monitoring of the γ-Ray Emitting Narrow-line Seyfert 1 Galaxy PMN J0948+0022 from 2020 to 2021
2022年
In order to study the physical properties of the γ-ray emitting narrow-line Seyfert 1(NLS1) galaxy population,photometric and spectral observations of the γ-ray emitting NLS1 PMN J0948+0022 were made with the Lijiang2.4 m optical telescope of Yunnan Observatories,Chinese Academy of Sciences.Photometric data in the B and R bands were collected for 50 nights from 2020 January to 2021 December.During the observation epoch,the variability amplitudes are 73.67% in the B band and 79.96% in the R band.Intra-day variability is found in two observation nights,and the duty cycle value is 29% with variability amplitude> 12.9% in the R band,which support the presence of the relativistic jets in the target.The redder-when-brighter(RWB) chromatic trend(or steeper-when-brighter trend) appears on intra-day and long timescales.The RWB trend is dominated by the radiation of accretion disk and jet,and resembles those in flat spectrum radio quasars.When PMN J0948+0022 is brighter than 17.5 in the R band,there is no color change trend.By analyzing the spectral data of PMN J0948+0022,we obtained the black hole mass of M.=1.61×10^(7) Mand accretion rate of M=93,and confirmed that PMN J0948+0022 is a super-Eddington accreting NLS1.The redshifts of reverberation mapped super-Eddington accreting active galactic nuclei can be expanded by PMN J0948+0022 up to above 0.5.Super-Eddington accreting NLS1 galaxies were chosen as a new type of cosmological candle in the literature.PMN J0948+0022 may be used as a target for the next step of reverberation mapping monitoring project of super-Eddington accreting massive black holes.
Yu-Xin XinDing-Rong XiongJin-Ming BaiHong-Tao LiuKai-Xing LuJi-Rong Mao

相关作者

张雄
作品数:210被引量:335H指数:9
供职机构:普洱学院
研究主题:星系 光变 光变周期 类星体 BLAZAR天体
黄介浩
作品数:7被引量:2H指数:1
供职机构:南京大学天文与空间科学学院
研究主题:星系 SEYFERT 英文 塞弗 恒星形成
程福臻
作品数:50被引量:80H指数:5
供职机构:中国科学技术大学物理学院
研究主题:星系 活动星系核 星族合成 电磁学 发射线
顾秋生
作品数:11被引量:3H指数:1
供职机构:南京大学天文与空间科学学院
研究主题:星系 塞弗 SEYFERT 英文 恒星
程富华
作品数:14被引量:1H指数:1
供职机构:中国科学技术大学
研究主题:类星体 连续谱 红移 星系 LY