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Investigating the co-evolution of massive black holes in dual active galactic nuclei and their host galaxies via galaxy merger simulations

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 96-109页

作者： Chao Yang JunQiang Ge You Jun Lu National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China

Major galaxy mergers can trigger nuclear activities and are responsible for high-luminosity quasi-stellar objects/active galactic nuclei(QSOs/AGNs). In certain circumstances, such mergers may cause dual active galactic nuclei(dAGN) phenomenon. This study investigates dAGN triggering and evolution of massive black holes(MBHs) during the merging processes using hydrodynamic code GADGET-2 to simulate several gas-rich major mergers at redshift z = 2 and 3, respectively. Results reveal that gas-rich major mergers can trigger significant nuclear activities after the second and third pericentric passages and the formation of dAGN with significant time duration(~10-390 Myr). During the merging processes, galactic bulge evolves with time because of the rapid star formation in each(or both) galactic centers and initial mixing of stars in galactic disks due to violent *** grow substantially due to accretion and finally merge into a bigger black hole. The growth of galactic bulges and corresponding increases of its velocity dispersions predate the growth of MBHs in the d AGN stages. The MBHs in these stages deviate below the relation between MBH mass and bulge mass(or velocity dispersion), and they revert to the relation after the final mergers due to the significant accretion that occurs mostly at a separation less than a few kpc. Then, the two MBHs merge with each other.

关键词： galaxies quasars black hole numerical simulations

A New 2MASS／2df Selected Sample of Pairs of galaxies and Calibration of Merging Rate in the Local Universe

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Chinese Physics Letters 2003年第9期20卷 1652-1655页

作者：孙艳春徐聪何香涛 DepartmentofAstronomy BeijingNormalUniversityBeijing100875 InfrareclProcessingandAnalysisCenter JetPropulsionLaboratoryCaliforniaInstituteofTechnology100-22PasadenaCA91125USA

We present a new sample of 37 close major-merger galaxy pairs, selected from the 2-degree field redshift survey of the two-micron all-sky survey (2MASS) galaxies. The selection criteria for our near-infrared pairs are more closely related to galaxy mass (a very important parameter in galaxy evolution models) than those for optical selected samples. Our sample benefits enormously from the high homogeneity and accuracy of the 2MASS database, and false matchings are minimized by the essentially three-dimensional selection procedure. Taking into account the biases, we find that 1.96 (±0.4)% of galaxies are in close major-merger pairs. This indicates a local merging rate of 1.0%, in good agreement with the results in recent studies of optical selected pairs in the local universe. The results derived with our sample have high confidence.

关键词： galaxies

Infrared Characters of Host galaxies with H_(2)O Megamaser

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Chinese Physics Letters 2001年第6期18卷 841-843页

作者： YU Zhi-Yao Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030 National Astronomical Observatories Chinese Academy of SciencesBeijing 100012

Infrared characters of all the host galaxies with H2O megamaser have been *** most striking feature is anticorrelation of S(60)/S(100)versus S(12)/S(25),and S(25)/S(60)versus S(12)/S(25).The anticorrelation in flux density ratio can been explained by coexistence of large and very small dust *** latter,which are heated by absorption of single photon,are believed to be resposible for bulk of 12μm *** the photon energy of the host galaxy is small,this implies large S(12)/S(25)and small S(60)/S(100).However,when photon energy density becomes larger,the infrared spectrum will peak at wavelengths≤100μm and enhance emission at 25μ*** a consequence small S(12)/S(25)and large S(60)/S(100)are observed.

关键词： galaxy striking galaxies

The abundance of massive compact galaxies at 1.0

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Research in Astronomy and Astrophysics 2019年第10期19卷 109-120页

作者： Shi-Ying Lu Yi-Zhou Gu Guan-Wen Fang Qi-Rong Yuan Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 China Institute for Astronomy and History of Science and Technology Dali UniversityDali 671003 China

Based on a large sample of massive(M* 1010 M⊙) compact galaxies at 1.0 < z < 3.0 in five 3 D-HST/CANDELS fields, we quantify the fractional abundance and comoving number density of massive compact galaxies as a funct... 详细信息

Based on a large sample of massive(M* 1010 M⊙) compact galaxies at 1.0 galaxies as a function of redshift. The samples of compact quiescent galaxies(cQGs) and compact star-forming galaxies(cSFGs) are constructed by various selection criteria of compact galaxies in the literature, and the effect of compactness definition on abundance estimate has proven to be remarkable,particularly for the cQGs and cSFGs at high redshifts. Regardless of the compactness criteria adopted,their overall redshift evolutions of fractional abundance and number density are found to be rather *** samples of the cQGs exhibit a sustained increase in number density from z ~ 3 to 2 and a plateau at 1 < z < 2. For massive cSFGs, a plateau in the number density at 2 < z < 3 can be found, as well as a continuous drop from z ~ 2 to 1. The evolutionary trends of the cQG and cSFG abundances support the scenario that the cSFGs at z≥ 2 may have been rapidly quenched into quiescent phase via violent dissipational processes, such as major merger and disk instabilities. The rarity of the cSFGs at lower redshifts(z < 1) can be interpreted by the decrease of gas reservoirs in dark matter halos and the consequent low efficiency of gas-rich dissipation.

关键词： galaxies high-redshift-galaxies massive-compact-galaxies evolution-galaxies

Physical Background of the Unified Scaling Law in Spiral galaxies

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Chinese Physics Letters 2000年第12期17卷 935-936页

作者： ZOU Zhen-Long HAN Jin-Lin Beijing Astronomical Observatory and Beijing Astrophysical Center National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012

We discussed the physical background of the unified scaling law in spiral galaxies,and qualitatively obtained the power index of the empirical relation among the luminosity L,radius R and the rotation velocity *** also discussed the possible causes for the data dispersion on the plane in three-dimensional space of these parameters.

关键词： parameters galaxies rotation

A New Method to Determine the Thickness of Spiral galaxies:Apply to M31

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Chinese Physics Letters 2000年第6期17卷 466-468页

作者： LI Meng LUO Xin-Lian PENG Qiu-He ZOU Zhi-Gang CHOU Chih-Kang Department of Astronomy Nanjing UniversityNanjing 210093 Chinese Academy of Sciences-Peking University Joint Beijing Astrophysical Center Peking UniversityBeijing 100871 Graduate Institute of Astronomy^National Central University Chung-Li32054TaiwanChina

A new method is presented to determine the thickness of spiral *** on the rigorous solution of the Poisson equation for logarithmic density disturbance in three-dimensional spiral galaxies,we have derived an accurate dispersion relation for the stellar and gaseous disk with a finite *** this relation,a new method is put forward here for determining the thickness of *** apply this way to M31 and get the thickness of about 0.7kpc,which is in good agreement with the previous results.

关键词： galaxies M31 stellar

On Three-Dimensional Spiral galaxies

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Chinese Physics Letters 2000年第12期17卷 932-934页

作者： LUO Xin-Lian PENG Qiu-He LONG Min PENG Fang ZOU Zhi-Gang Department of Astronomy Nanjing UniversityNanjing 210093 Chinese Academy of Sciences-Peking University Joint Beijing Astrophysical Center Beijing UniversityBeijing 100871 Graduate Institute of Astronomy National Central UniversityChung-Li32054TaiwanChina

Density waves in 3D spiral galaxies are *** order to eliminate the forbidden region near the corotation in the grand-design galaxies,we assume that the perturbation satisfies the stable condition Q(r)>1 over all the disk except that at the ***,a new method is put forward here to determine some basic parameters of spiral *** apply it to our Galaxy,and the results are in good agreement with the previous results.

关键词： rotation. galaxies spiral

What properties correlate with molecular-to-atomic gas ratios in galaxies

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 201-202页

作者： Renbin Yan Department of Physics the Chinese University of Hong KongHong Kong 999077China

The baryon cycle in and around galaxies is a critical piece of the picture of galaxy *** form out of *** stars evolve and die,they return gas back into the interstellar medium(ISM)but pollute it with newly synthesized heavy elements,whose abundance relative to hydrogen is referred to as metallicity by *** can also flow into galaxies due to gravity and out of galaxies due to energetic feedback from massive stars,supernovae,and active galactic nuclei.

关键词： evolution galaxies stars

An Infrared Photometric Study of galaxies with Extragalactic H_2O Maser Sources

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Chinese Journal of Astronomy and Astrophysics 2007年第5期7卷 657-668页

作者： Pei-Sheng Chen Yi-Fei Gao Hong-Guang Shan National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011

All galaxies with extragalactic H2O maser sources observed so far are collected. With the 2MASS and the IRAS photometric data an infrared study is performed on those galaxies. By a comparison between the H2O maser detected sources and non-detected sources in the infrared it is indicated that infrared properties in the IRAS 12-25 #m and 60-100#m are important for producing H20 masers in galaxies. It is also found that the H20 maser galaxies with different nuclear activity types have rather different infrared properties mainly in the IRAS 12-60 μm region.

关键词： galaxies maser -- galaxies nuclei -- galaxies starburst -- infrared galaxies