In Part 1 of this work, we showed that our new model of cosmology can account for the origin of all cosmic structures ranging in size from stars up to superclusters. In this model, at the time of nucleosynthesis, an i...In Part 1 of this work, we showed that our new model of cosmology can account for the origin of all cosmic structures ranging in size from stars up to superclusters. In this model, at the time of nucleosynthesis, an imprint embedded in the vacuum regulated the creation of the protons (and electrons) that later made up the structures. Immediately after nucleosynthesis and for a considerable period afterward, the evolution was completely determined by the expansion of the universe. Gradually, however, gravitational influences became more important until finally, the expansion of the structures-to-be ceased at their zero velocity points. Stars, galaxies, and galaxy clusters all reached their zero velocity points more or less simultaneously at the usually accepted time of the beginning of galaxy formation. From that point onward, the evolution gravitation came to dominate the evolution although the expansion still exerted its influence. In this paper, we examine the subsequent cluster evolution in some detail. We establish the conditions required to prevent a free-fall collapse of the clusters and then show that galaxies with quasar-like active nuclei located within the cluster were the sources of the necessary radiation. We also show that the required galactic supermassive black holes were a consequence of the initial free-fall collapse of all galaxies.展开更多
Quasars with periodic light curves are considered as candidates of supermassive binary black hole(BBH)systems.One way for further confirmations may be searching for other characteristic signatures,such as those in the...Quasars with periodic light curves are considered as candidates of supermassive binary black hole(BBH)systems.One way for further confirmations may be searching for other characteristic signatures,such as those in their broad emission lines(BELs),if any,which require a thorough understanding on the response of BELs to the BBH systems.In Ji et al.(2021),we have investigated the response of circumbinary broad line region(BLR)to the central active secondary black hole under the relativistic Doppler boosting(BBH-DB)and intrinsic variation(BBH-IntDB)dominant mechanisms for continuum variation by assuming the middle plane of the BLR aligned with the BBH orbital plane.In this paper,we explore how the BEL profiles vary when the BLR is misaligned from the BBH orbital plane with different offset angles under both the BBH-DB and BBH-IntDB scenarios.Given a fixed inclination angle of the BBH orbital plane viewed in edge-on and similar continuum light curves produced by the two scenarios,increasing offset angles make the initial opening angle of the circumbinary BLR enlarged due to orbital precession caused by the BBH system,especially for clouds in the inner region,which result in Lorentzlike BEL profiles for the BBH-DB model but still Gaussion-like profiles for the BBH-IntDB model at the vertical BLR case.The amplitude of profile variations decreases with increasing offset angles for the BBHDB scenario,while keeps nearly constant for the BBH-IntDB scenario,since the Doppler boosting effect is motion direction preferred but the intrinsic variation is radiated isotropically.If the circumbinary BLR is composed of a coplanar and a vertical components with their number of clouds following the mass ratio of the BBHs,then the bi-BLR features are more significant for the BBH-IntDB model that requires larger mass ratio to generate similar continuum variation than the BBH-DB model.展开更多
Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still unknown.In this paper,we investigate the formation of SMBHs from the quantum chromodynamics(Q...Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still unknown.In this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion bubbles.In this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after inflation.The QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase transition.We consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))GeV.The PBHs at this mass region may account for the seeds of SMBHs.展开更多
The coevolution between supermassive black holes(SMBHs) and their host galaxies has been proposed for more than a decade,albeit with little direct evidence about black hole accretion activities regulating galaxy star ...The coevolution between supermassive black holes(SMBHs) and their host galaxies has been proposed for more than a decade,albeit with little direct evidence about black hole accretion activities regulating galaxy star formation at z> 1.In this paper,we study the lifetimes of X-ray active galactic nuclei(AGNs) in UV-selected red sequence(RS),blue cloud(BC) and green valley(GV) galaxies,finding that AGN accretion activities are most prominent in GV galaxies at z ~1.5-2,compared with RS and BC galaxies.We also compare AGN accretion timescales with typical color transition timescales of UV-selected galaxies.We find that the lifetime of GV galaxies at z~1.5-2 is very close to the typical timescale when the AGNs residing in them stay in the high-accretion-rate mode at these redshifts;for BC galaxies,the consistency between the color transition timescale and the black hole strong accretion lifetime is more likely to happen at lower redshifts(z <1).Our results support the scenario where AGN accretion activities govern UV color transitions of host galaxies,making galaxies and their central SMBHs coevolve with each other.展开更多
It is crucial to measure the mass of supermassive black holes(SMBHs)in understanding the co-evolution between the SMBHs and their host galaxies.Previous methods usually require spectral data which are expensive to obt...It is crucial to measure the mass of supermassive black holes(SMBHs)in understanding the co-evolution between the SMBHs and their host galaxies.Previous methods usually require spectral data which are expensive to obtain.We use the AGN catalog from the Sloan Digital Sky Survey project Data Release 7(DR7)to investigate the correlations between SMBH mass and their host galaxy properties.We apply the machine learning algorithms,such as Lasso regression,to establish the correlation between the SMBH mass and various photometric properties of their host galaxies.We find an empirical formula that can predict the SMBH mass according to galaxy luminosity,colors,surface brightness,and concentration.The root-mean-square error is 0.5 dex,comparable to the intrinsic scatter in SMBH mass measurements.The 1σscatter in the relation between the SMBH mass and the combined galaxy properties relation is 0.48 dex,smaller than the scatter in the SMBH mass versus galaxy stellar mass relation.This relation could be used to study the SMBH mass function and the AGN duty cycles in the future.展开更多
Inspired by the General Relativity for many decades,experimental physicists and astronomers have a solid dream to detect gravitational waves(GWs)from mergers of black holes,which came true until the excellent performa...Inspired by the General Relativity for many decades,experimental physicists and astronomers have a solid dream to detect gravitational waves(GWs)from mergers of black holes,which came true until the excellent performance of the Laser Interferometer Gravitational-Wave Observatory(LIGO)at hundreds Hz.Nano-Hz GWs are expected to be radiated by close-binaries of supermassive black holes(CB-SMBHs;defined as those with separations less than^0.1 pc)formed during galaxy mergers and detected through the Pulsar Timing Array(PTA)technique.As of the writing,there remains no nano-Hz GWs detection.Searching for CB-SMBHs is also observationally elusive though there exist a number of possible candidates.In this review,we focus on observational signatures of CB-SMBHs from theoretic expectations,simulations and observations.These signatures appear in energy distributions of multiwavelength continuum,long term variations of continuum,jet morphology,reverberation delay maps and spectroastrometry of broad emission lines,AGN type transitions between type-1 and type-2(changing-look),and gaseous dynamics of circumbinary disks,etc.Unlike hundred-Hz GWs from stellar mass black hole binaries,the waveform chirping of nano-Hz GWs is too slow to detect in a reasonable human timescale.We have to resort to electromagnetic observations to measure orbital parameters of CB-SMBHs to test nano-Hz GW properties.Reverberation mapping is a powerful tool for probing kinematics and geometry of ionized gas in the gravitational well of SMBHs(single or binary)and therefore provides a potential way to determine orbital parameters of CB-SMBHs.In particular,a combination of reverberation mapping with spectroastrometry(realized at the Very Large Telescope Interferometer)will further reinforce this capability.The Atacama Large Millimeter/submillimeter Array(ALMA)and the forthcoming Square Kilometre Array(SKA)are suggested to reveal dynamics of circumbinary disks through molecular emission lines.展开更多
Recently,observational hints for supermassive black holes have been accumulating,prompting the question:Can primordial black holes(PBHs)be supermassive,particularly with masses M■10^(9)M_(⊙)?A supercritical bubble,c...Recently,observational hints for supermassive black holes have been accumulating,prompting the question:Can primordial black holes(PBHs)be supermassive,particularly with masses M■10^(9)M_(⊙)?A supercritical bubble,containing an inflating baby universe,that nucleated during inflation can evolve into a PBH in our observable universe.We find that when the inflaton slowly transitions past a neighboring vacuum,the nucleation rate of supercritical bubbles inevitably peaks,leading to a mass distribution of multiverse PBHs with a peak mass up to M■10^(11)M_(⊙).Thus,our mechanism naturally provides a primordial origin for supermassive black holes.展开更多
A holographic analysis of large scale structure in the universe provides an upper bound on the mass of supermassive black holes at the center of large scale structures with matter density varying as as a function of d...A holographic analysis of large scale structure in the universe provides an upper bound on the mass of supermassive black holes at the center of large scale structures with matter density varying as as a function of distance r from their center. The upper bound is consistent with two important test cases involving observations of the supermassive black hole with mass times the galactic mass in Sagittarius A* near the center of our Milky Way and the 2 × 109 solar mass black hole in the quasar ULAS J112001.48 + 064124.3 at redshift z = 7.085. It is also consistent with upper bounds on central black hole masses in globular clusters M15, M19 and M22 developed using the Jansky Very Large Array in New Mexico.展开更多
All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes ont...All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center展开更多
Several pulsar timing array(PTA)collaborations,including NANOGrav,EPTA,PPTA,and CPTA,have announced the evidence for a stochastic signal consistent with a stochastic gravitational wave background(SGWB).Supermassive bl...Several pulsar timing array(PTA)collaborations,including NANOGrav,EPTA,PPTA,and CPTA,have announced the evidence for a stochastic signal consistent with a stochastic gravitational wave background(SGWB).Supermassive black hole binaries(SMBHBs)are supposed to be the most promising gravitational-wave(GW)sources for this signal.In this paper,we use the NANOGrav 15-year data set to constrain the parameter space in an astro-informed formation model for SMBHBs.Our results prefer a large turn-over eccentricity of the SMBHB orbit when GWs begin to dominate the SMBHB evolution.Furthermore,the SGWB spectrum is extrapolated to the space-borne GW detector frequency band by including inspiral-merge-cutoff phases of SMBHBs,indicating that the SGWB from SMBHBs should be detected by LISA,Taiji and Tian Qin in the near future.展开更多
In the frequency band of the Laser Interferometer Space Antenna(LISA),extensive research has been conducted on the impact of foreground confusion noise generated by galactic binaries within the Milky Way Galaxy.Additi...In the frequency band of the Laser Interferometer Space Antenna(LISA),extensive research has been conducted on the impact of foreground confusion noise generated by galactic binaries within the Milky Way Galaxy.Additionally,recent evidence of a stochastic signal,announced by the NANOGrav,EPTA,PPTA,CPTA,and InPTA,indicates that the stochastic gravitational-wave background(SGWB)generated by supermassive black hole binaries(SMBHBs)can contribute strong background noise within the LISA band.Given the presence of such strong noise,it is expected to have significant impacts on LISA's scientific missions.In this study,we investigate the impacts of the SGWB generated by SMBHBs on the detection of individual massive black hole binaries,verified galactic binaries,and extreme mass ratio inspirals in the context of LISA.We find it essential to resolve and eliminate the excess noise from the SGWB to guarantee the success of LISA's missions.展开更多
We present the optical light curves of the tidal disruption event AT 2023clx in the declining phase,observed with Mephisto.Combining our light curve with the ASAS-SN and ATLAS data in the rising phase,and fitting the ...We present the optical light curves of the tidal disruption event AT 2023clx in the declining phase,observed with Mephisto.Combining our light curve with the ASAS-SN and ATLAS data in the rising phase,and fitting the composite multi-band light curves with MOSFiT,we estimate black hole mass for AT 2023clx is between 10^(5.67)and 10^(5.82)M_(⊙).This event may be caused by either a full disruption of a 0.1M_(⊙)star,or a partial disruption of a 0.99M_(⊙) star,depending on the data adopted for the rising phase.Based on those fit results and the non-detection of soft X-ray photons in the first 90 days,we propose that the observed optical radiation is powered by stream-stream collision.We speculate that the soft X-ray photons may gradually emerge in 100-600 days after the optical peak,when the debris is fully circularized into a compact accretion disk.展开更多
We estimated radiative efficiency,spin and supermassive black hole(SMBH)mass values for sample of 33 distant low luminosity active galactic nuclei(AGNs).The distribution of the estimated spin values(majority of object...We estimated radiative efficiency,spin and supermassive black hole(SMBH)mass values for sample of 33 distant low luminosity active galactic nuclei(AGNs).The distribution of the estimated spin values(majority of objects have a spin greater than 0.8)is fairly typical for many types of AGNs.The dependence of the estimated spin values on the estimated SMBH masses shows strong correlation between them,which suggests a rapid increase in spin with mass,i.e.,that the main mechanism of mass growth in this case is disk accretion.We did not find any significant qualitative differences in the spin characteristics between our objects and objects of other types considered in the paper.展开更多
In this work,we report for the first time two repeated quasi-periodic oscillations(QPOs)in the light curve of the Flat Spectrum Radio Quasar S51044+71.This source was observed by the Transiting Exoplanet Survey Satell...In this work,we report for the first time two repeated quasi-periodic oscillations(QPOs)in the light curve of the Flat Spectrum Radio Quasar S51044+71.This source was observed by the Transiting Exoplanet Survey Satellite in multiple sectors.We used the generalized Lomb-Scargle periodogram method and weighted wavelet Z-transform method to search for significant periodic signals.The main results are as follows:We found QPOs of~7.0 days(persisted for 4 cycles,with a significance of~3.5σ)and~7.3 days(persisted for 5 cycles,with a significance of~3.8σ)in the light curves of Sector 47 and EP1,respectively.Considering range of error,we regard them to be the same.We discussed two likely models of these rapid quasi-periodic variations:One comes from the jet and the other from the accretion disk.For the first one,we consider kink instability of the jet as a plausible explanation.Second,the QPO probably comes from the main hot spots in the accretion disk,which are located approximately within the innermost stable circular orbit allowed by general relativity.Based on this model,we estimate the mass of the black hole in S51044+71 to be 3.49×10^(9)M☉.展开更多
Tidal disruption events(TDEs),which occur when stars enter the tidal radii of supermassive black holes(SMBHs)and are subsequently torn apart by their tidal forces,represent intriguing phenomena that stimulate growing ...Tidal disruption events(TDEs),which occur when stars enter the tidal radii of supermassive black holes(SMBHs)and are subsequently torn apart by their tidal forces,represent intriguing phenomena that stimulate growing research interest and pose an increasing number of puzzles in the era of time-domain astronomy.展开更多
We use a semi-analytic galaxy formation model to study the co-evolution of supermassive black holes(SMBHs) with their host galaxies.Although the coalescence of SMBHs is not important,the quasarmode accretion induced b...We use a semi-analytic galaxy formation model to study the co-evolution of supermassive black holes(SMBHs) with their host galaxies.Although the coalescence of SMBHs is not important,the quasarmode accretion induced by mergers plays a dominant role in the growth of SMBHs.Mergers play a more important role in the growth of SMBH host galaxies than in the SMBH growth.It is the combined contribution from quasar mode accretion and mergers to the SMBH growth and the combined contribution from starburst and mergers to their host galaxy growth that determine the observed scaling relation between the SMBH masses and their host galaxy masses.We also find that mergers are more important in the growth of SMBH host galaxies compared to normal galaxies which share the same stellar mass range as the SMBH host galaxies.展开更多
In 2013, World-Universe Model (WUM) made one of the most important predictions: “Macroobjects of the World have cores made up of the discussed DM (Dark Matter) particles. Other particles, including DM and baryonic ma...In 2013, World-Universe Model (WUM) made one of the most important predictions: “Macroobjects of the World have cores made up of the discussed DM (Dark Matter) particles. Other particles, including DM and baryonic matter, form shells surrounding the cores” [1]. Prof. R. Genzel and A. Ghez confirmed this prediction: “The Discovery of a Supermassive Compact Object at the Centre of Our Galaxy” (Nobel Prize in Physics 2020). On May 12, 2022, astronomers, using the Event Horizon Telescope, released the first image of the accretion disk around the Sagittarius A* (Sgr A*) produced using a worldwide network of radio observatories made in April 2017. These observations were obtained by a global array of millimeter wavelength telescopes and analyzed by an international research team that now numbers over 300 people, which claimed that Sgr A* is a Supermassive Black Hole (SBH). In the present paper, we analyze these results in frames of WUM. Based on the totality of all accumulated experimental results for the Center of the Milky Way Galaxy we conclude that Sgr A* is the DM Core of our Galaxy.展开更多
An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approx...An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approximating equation for the orography gravity waves is obtained. Four topography functions are considered in this study and the orography gravity wave are obtained. The dynamics of the orography gravity wave is then discussed by considering the effect of the surface topography and background horizontal wind.展开更多
A preliminary estimation of gravitational waves(GWs) from the extreme-mass-ratio-inspirals(EMRIs)system in the Galactic Centre(GC) is given for the 37 observed S-stars revolving around the supermassive black hole(SMBH...A preliminary estimation of gravitational waves(GWs) from the extreme-mass-ratio-inspirals(EMRIs)system in the Galactic Centre(GC) is given for the 37 observed S-stars revolving around the supermassive black hole(SMBH) at Sagittarius(Sgr) A*. Within this century, the total strain of the gravitational waveform calculated from the post-Newtonian(PN) method with eccentricity is well below the current planned sensitivity of pulsar-timing-array(PTA). New technology might be required in order to extract GW signal from this EMRIs system for future PTA detections.展开更多
文摘In Part 1 of this work, we showed that our new model of cosmology can account for the origin of all cosmic structures ranging in size from stars up to superclusters. In this model, at the time of nucleosynthesis, an imprint embedded in the vacuum regulated the creation of the protons (and electrons) that later made up the structures. Immediately after nucleosynthesis and for a considerable period afterward, the evolution was completely determined by the expansion of the universe. Gradually, however, gravitational influences became more important until finally, the expansion of the structures-to-be ceased at their zero velocity points. Stars, galaxies, and galaxy clusters all reached their zero velocity points more or less simultaneously at the usually accepted time of the beginning of galaxy formation. From that point onward, the evolution gravitation came to dominate the evolution although the expansion still exerted its influence. In this paper, we examine the subsequent cluster evolution in some detail. We establish the conditions required to prevent a free-fall collapse of the clusters and then show that galaxies with quasar-like active nuclei located within the cluster were the sources of the necessary radiation. We also show that the required galactic supermassive black holes were a consequence of the initial free-fall collapse of all galaxies.
基金supported by the National Key R&D Program of China(Grant Nos.2020YFC2201400,2020SKA0120102,and 2016YFA0400704)the National Natural Science Foundation of China(Grant Nos.11690024,11873056,and 11991052)+1 种基金the Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB 23040100)the Beijing Municipal Natural Science Foundation(Grant No.1204038)。
文摘Quasars with periodic light curves are considered as candidates of supermassive binary black hole(BBH)systems.One way for further confirmations may be searching for other characteristic signatures,such as those in their broad emission lines(BELs),if any,which require a thorough understanding on the response of BELs to the BBH systems.In Ji et al.(2021),we have investigated the response of circumbinary broad line region(BLR)to the central active secondary black hole under the relativistic Doppler boosting(BBH-DB)and intrinsic variation(BBH-IntDB)dominant mechanisms for continuum variation by assuming the middle plane of the BLR aligned with the BBH orbital plane.In this paper,we explore how the BEL profiles vary when the BLR is misaligned from the BBH orbital plane with different offset angles under both the BBH-DB and BBH-IntDB scenarios.Given a fixed inclination angle of the BBH orbital plane viewed in edge-on and similar continuum light curves produced by the two scenarios,increasing offset angles make the initial opening angle of the circumbinary BLR enlarged due to orbital precession caused by the BBH system,especially for clouds in the inner region,which result in Lorentzlike BEL profiles for the BBH-DB model but still Gaussion-like profiles for the BBH-IntDB model at the vertical BLR case.The amplitude of profile variations decreases with increasing offset angles for the BBHDB scenario,while keeps nearly constant for the BBH-IntDB scenario,since the Doppler boosting effect is motion direction preferred but the intrinsic variation is radiated isotropically.If the circumbinary BLR is composed of a coplanar and a vertical components with their number of clouds following the mass ratio of the BBHs,then the bi-BLR features are more significant for the BBH-IntDB model that requires larger mass ratio to generate similar continuum variation than the BBH-DB model.
基金supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 11775025 and No. 12175027)supported by the National Key R&D Program of China (Grant No. 2017YFA0402204)+1 种基金the CAS Project for Young Scientists in Basic Research YSBR-006the National Natural Science Foundation of China (NSFC) (Grant Nos. 11821505, No. 11825506, and No. 12047503)
文摘Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still unknown.In this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion bubbles.In this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after inflation.The QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase transition.We consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))GeV.The PBHs at this mass region may account for the seeds of SMBHs.
基金support from the National Natural Science Foundation of China (grant Nos. 12025303, 11890693,11421303 and 12003031)the CAS Frontier Science Key Research Program (QYZDJ-SSW-SLH006)+2 种基金the K.C. Wong Education Foundationthe science research grants from the China Manned Space Project with No. CMS-CSST-2021-A06support from the Chinese Academy of Sciences President’s International Fellowship Initiative (grant No. 2019PM0020)。
文摘The coevolution between supermassive black holes(SMBHs) and their host galaxies has been proposed for more than a decade,albeit with little direct evidence about black hole accretion activities regulating galaxy star formation at z> 1.In this paper,we study the lifetimes of X-ray active galactic nuclei(AGNs) in UV-selected red sequence(RS),blue cloud(BC) and green valley(GV) galaxies,finding that AGN accretion activities are most prominent in GV galaxies at z ~1.5-2,compared with RS and BC galaxies.We also compare AGN accretion timescales with typical color transition timescales of UV-selected galaxies.We find that the lifetime of GV galaxies at z~1.5-2 is very close to the typical timescale when the AGNs residing in them stay in the high-accretion-rate mode at these redshifts;for BC galaxies,the consistency between the color transition timescale and the black hole strong accretion lifetime is more likely to happen at lower redshifts(z <1).Our results support the scenario where AGN accretion activities govern UV color transitions of host galaxies,making galaxies and their central SMBHs coevolve with each other.
基金the National Key Research and Development of China(Grant No.2018YFA0404503)NSFC(Grant Nos.12033008 and 11988101)+1 种基金the K.C.Wong Education Foundationthe science research grants from the China·Manned Space Project with No.CMS-CSST-2021-A03。
文摘It is crucial to measure the mass of supermassive black holes(SMBHs)in understanding the co-evolution between the SMBHs and their host galaxies.Previous methods usually require spectral data which are expensive to obtain.We use the AGN catalog from the Sloan Digital Sky Survey project Data Release 7(DR7)to investigate the correlations between SMBH mass and their host galaxy properties.We apply the machine learning algorithms,such as Lasso regression,to establish the correlation between the SMBH mass and various photometric properties of their host galaxies.We find an empirical formula that can predict the SMBH mass according to galaxy luminosity,colors,surface brightness,and concentration.The root-mean-square error is 0.5 dex,comparable to the intrinsic scatter in SMBH mass measurements.The 1σscatter in the relation between the SMBH mass and the combined galaxy properties relation is 0.48 dex,smaller than the scatter in the SMBH mass versus galaxy stellar mass relation.This relation could be used to study the SMBH mass function and the AGN duty cycles in the future.
基金financial support from the National Natural Science Foundation of China(11833008 and 11991054)from the National Key R&D Program of China(2016YFA0400701)+2 种基金from the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(CASQYZDJ-SSW-SLH007)from the CAS Key Research Program(KJZD-EW-M06)。
文摘Inspired by the General Relativity for many decades,experimental physicists and astronomers have a solid dream to detect gravitational waves(GWs)from mergers of black holes,which came true until the excellent performance of the Laser Interferometer Gravitational-Wave Observatory(LIGO)at hundreds Hz.Nano-Hz GWs are expected to be radiated by close-binaries of supermassive black holes(CB-SMBHs;defined as those with separations less than^0.1 pc)formed during galaxy mergers and detected through the Pulsar Timing Array(PTA)technique.As of the writing,there remains no nano-Hz GWs detection.Searching for CB-SMBHs is also observationally elusive though there exist a number of possible candidates.In this review,we focus on observational signatures of CB-SMBHs from theoretic expectations,simulations and observations.These signatures appear in energy distributions of multiwavelength continuum,long term variations of continuum,jet morphology,reverberation delay maps and spectroastrometry of broad emission lines,AGN type transitions between type-1 and type-2(changing-look),and gaseous dynamics of circumbinary disks,etc.Unlike hundred-Hz GWs from stellar mass black hole binaries,the waveform chirping of nano-Hz GWs is too slow to detect in a reasonable human timescale.We have to resort to electromagnetic observations to measure orbital parameters of CB-SMBHs to test nano-Hz GW properties.Reverberation mapping is a powerful tool for probing kinematics and geometry of ionized gas in the gravitational well of SMBHs(single or binary)and therefore provides a potential way to determine orbital parameters of CB-SMBHs.In particular,a combination of reverberation mapping with spectroastrometry(realized at the Very Large Telescope Interferometer)will further reinforce this capability.The Atacama Large Millimeter/submillimeter Array(ALMA)and the forthcoming Square Kilometre Array(SKA)are suggested to reveal dynamics of circumbinary disks through molecular emission lines.
基金supported by the National Natural Science Foundation of China(NSFC,grant No.12075246)the Fundamental Research Funds for the Central Universities+5 种基金the Fundamental Research Funds for the Central Universities(grant No.E2EG6602X2 and grant No.E2ET0209X2)supported in part by the Natural Science Foundation of Henan Province and Zhengzhou University(grant Nos.242300420231,JC23149007,35220136)the China Postdoctoral Science Foundation(grant No.2021M692942)the NSFC(grant No.11905224)the NSFC(grant No,12147103)supported by the scientific research starting grants from University of Chinese Academy of Sciences(grant No.118900M061)。
文摘Recently,observational hints for supermassive black holes have been accumulating,prompting the question:Can primordial black holes(PBHs)be supermassive,particularly with masses M■10^(9)M_(⊙)?A supercritical bubble,containing an inflating baby universe,that nucleated during inflation can evolve into a PBH in our observable universe.We find that when the inflaton slowly transitions past a neighboring vacuum,the nucleation rate of supercritical bubbles inevitably peaks,leading to a mass distribution of multiverse PBHs with a peak mass up to M■10^(11)M_(⊙).Thus,our mechanism naturally provides a primordial origin for supermassive black holes.
文摘A holographic analysis of large scale structure in the universe provides an upper bound on the mass of supermassive black holes at the center of large scale structures with matter density varying as as a function of distance r from their center. The upper bound is consistent with two important test cases involving observations of the supermassive black hole with mass times the galactic mass in Sagittarius A* near the center of our Milky Way and the 2 × 109 solar mass black hole in the quasar ULAS J112001.48 + 064124.3 at redshift z = 7.085. It is also consistent with upper bounds on central black hole masses in globular clusters M15, M19 and M22 developed using the Jansky Very Large Array in New Mexico.
文摘All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center
基金supported by the National Natural Science Foundation of China(Grant Nos.12250010,11975019,11991052,and 12047503)the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-7009)+3 种基金the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-006)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB15)supported by the National Natural Science Foundation of China(Grant Nos.12247176,and 12247112)the China Postdoctoral Science Foundation Fellowship(Grant No.2022M710429)。
文摘Several pulsar timing array(PTA)collaborations,including NANOGrav,EPTA,PPTA,and CPTA,have announced the evidence for a stochastic signal consistent with a stochastic gravitational wave background(SGWB).Supermassive black hole binaries(SMBHBs)are supposed to be the most promising gravitational-wave(GW)sources for this signal.In this paper,we use the NANOGrav 15-year data set to constrain the parameter space in an astro-informed formation model for SMBHBs.Our results prefer a large turn-over eccentricity of the SMBHB orbit when GWs begin to dominate the SMBHB evolution.Furthermore,the SGWB spectrum is extrapolated to the space-borne GW detector frequency band by including inspiral-merge-cutoff phases of SMBHBs,indicating that the SGWB from SMBHBs should be detected by LISA,Taiji and Tian Qin in the near future.
基金Supported by the NSFC(12250010,11991052)Key Research Program of Frontier Sciences,CAS,(ZDBS-LY-7009)。
文摘In the frequency band of the Laser Interferometer Space Antenna(LISA),extensive research has been conducted on the impact of foreground confusion noise generated by galactic binaries within the Milky Way Galaxy.Additionally,recent evidence of a stochastic signal,announced by the NANOGrav,EPTA,PPTA,CPTA,and InPTA,indicates that the stochastic gravitational-wave background(SGWB)generated by supermassive black hole binaries(SMBHBs)can contribute strong background noise within the LISA band.Given the presence of such strong noise,it is expected to have significant impacts on LISA's scientific missions.In this study,we investigate the impacts of the SGWB generated by SMBHBs on the detection of individual massive black hole binaries,verified galactic binaries,and extreme mass ratio inspirals in the context of LISA.We find it essential to resolve and eliminate the excess noise from the SGWB to guarantee the success of LISA's missions.
基金the South-Western Institute for Astronomy Research of Yunnan University(SWIFAR-YNU),funded by the“Yunnan University Development Plan for World-Class University”and“Yunnan University Development Plan for World-Class Astronomy Discipline.”The authors acknowledge support from the“Science&Technology Champion Project”(202005AB160002)from two“Team Projects”-the“Innovation Team”(202105AE160021)the“Top Team”(202305AT350002)'funded by the“Yunnan Revitalization Talent Support Program.”。
文摘We present the optical light curves of the tidal disruption event AT 2023clx in the declining phase,observed with Mephisto.Combining our light curve with the ASAS-SN and ATLAS data in the rising phase,and fitting the composite multi-band light curves with MOSFiT,we estimate black hole mass for AT 2023clx is between 10^(5.67)and 10^(5.82)M_(⊙).This event may be caused by either a full disruption of a 0.1M_(⊙)star,or a partial disruption of a 0.99M_(⊙) star,depending on the data adopted for the rising phase.Based on those fit results and the non-detection of soft X-ray photons in the first 90 days,we propose that the observed optical radiation is powered by stream-stream collision.We speculate that the soft X-ray photons may gradually emerge in 100-600 days after the optical peak,when the debris is fully circularized into a compact accretion disk.
文摘We estimated radiative efficiency,spin and supermassive black hole(SMBH)mass values for sample of 33 distant low luminosity active galactic nuclei(AGNs).The distribution of the estimated spin values(majority of objects have a spin greater than 0.8)is fairly typical for many types of AGNs.The dependence of the estimated spin values on the estimated SMBH masses shows strong correlation between them,which suggests a rapid increase in spin with mass,i.e.,that the main mechanism of mass growth in this case is disk accretion.We did not find any significant qualitative differences in the spin characteristics between our objects and objects of other types considered in the paper.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.12203041,12063007,and 11863007)Yunnan Province China-Malaysia HF-VHF Advanced Radio Astronomy Technology International Joint Laboratory(No.202303AP140003)。
文摘In this work,we report for the first time two repeated quasi-periodic oscillations(QPOs)in the light curve of the Flat Spectrum Radio Quasar S51044+71.This source was observed by the Transiting Exoplanet Survey Satellite in multiple sectors.We used the generalized Lomb-Scargle periodogram method and weighted wavelet Z-transform method to search for significant periodic signals.The main results are as follows:We found QPOs of~7.0 days(persisted for 4 cycles,with a significance of~3.5σ)and~7.3 days(persisted for 5 cycles,with a significance of~3.8σ)in the light curves of Sector 47 and EP1,respectively.Considering range of error,we regard them to be the same.We discussed two likely models of these rapid quasi-periodic variations:One comes from the jet and the other from the accretion disk.For the first one,we consider kink instability of the jet as a plausible explanation.Second,the QPO probably comes from the main hot spots in the accretion disk,which are located approximately within the innermost stable circular orbit allowed by general relativity.Based on this model,we estimate the mass of the black hole in S51044+71 to be 3.49×10^(9)M☉.
文摘Tidal disruption events(TDEs),which occur when stars enter the tidal radii of supermassive black holes(SMBHs)and are subsequently torn apart by their tidal forces,represent intriguing phenomena that stimulate growing research interest and pose an increasing number of puzzles in the era of time-domain astronomy.
基金supported by NSFC grants (Nos.11573033,11622325,11425312 and 11988101)supported by NSFC grant (No.11803045)+2 种基金the “Recruitment Program of Global Youth Experts” of China,the NAOC (Grant Y434011V01)supported by the National Key R&D Program of China (No.2017YFB0203300)the Key Program of NFSC (Grant 11733010)。
文摘We use a semi-analytic galaxy formation model to study the co-evolution of supermassive black holes(SMBHs) with their host galaxies.Although the coalescence of SMBHs is not important,the quasarmode accretion induced by mergers plays a dominant role in the growth of SMBHs.Mergers play a more important role in the growth of SMBH host galaxies than in the SMBH growth.It is the combined contribution from quasar mode accretion and mergers to the SMBH growth and the combined contribution from starburst and mergers to their host galaxy growth that determine the observed scaling relation between the SMBH masses and their host galaxy masses.We also find that mergers are more important in the growth of SMBH host galaxies compared to normal galaxies which share the same stellar mass range as the SMBH host galaxies.
文摘In 2013, World-Universe Model (WUM) made one of the most important predictions: “Macroobjects of the World have cores made up of the discussed DM (Dark Matter) particles. Other particles, including DM and baryonic matter, form shells surrounding the cores” [1]. Prof. R. Genzel and A. Ghez confirmed this prediction: “The Discovery of a Supermassive Compact Object at the Centre of Our Galaxy” (Nobel Prize in Physics 2020). On May 12, 2022, astronomers, using the Event Horizon Telescope, released the first image of the accretion disk around the Sagittarius A* (Sgr A*) produced using a worldwide network of radio observatories made in April 2017. These observations were obtained by a global array of millimeter wavelength telescopes and analyzed by an international research team that now numbers over 300 people, which claimed that Sgr A* is a Supermassive Black Hole (SBH). In the present paper, we analyze these results in frames of WUM. Based on the totality of all accumulated experimental results for the Center of the Milky Way Galaxy we conclude that Sgr A* is the DM Core of our Galaxy.
基金Supported by the Natural Science Foundation of China under Grant Nos.91437215,41575047The Third Scientific Experiment of Tibetan Plateau under Grant No.GYHY201406001
文摘An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approximating equation for the orography gravity waves is obtained. Four topography functions are considered in this study and the orography gravity wave are obtained. The dynamics of the orography gravity wave is then discussed by considering the effect of the surface topography and background horizontal wind.
基金Supported by the Natural Science Foundation of China under Grant Nos.11690022,11375247,11435006,and 11647601the Strategic Priority Research Program of CAS under Grant No.XDB23030100the Key Research Program of Frontier Sciences of CAS
文摘A preliminary estimation of gravitational waves(GWs) from the extreme-mass-ratio-inspirals(EMRIs)system in the Galactic Centre(GC) is given for the 37 observed S-stars revolving around the supermassive black hole(SMBH) at Sagittarius(Sgr) A*. Within this century, the total strain of the gravitational waveform calculated from the post-Newtonian(PN) method with eccentricity is well below the current planned sensitivity of pulsar-timing-array(PTA). New technology might be required in order to extract GW signal from this EMRIs system for future PTA detections.
