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Close Major-merger Pairs at z=0: Star-forming galaxies with Pseudobulges

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Research in Astronomy and Astrophysics 2024年第5期24卷 35-60页

作者：何川徐聪 Ute Lisenfeld 戴昱方陶陶黄家声王炜余清正 Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Departamento de Física Teórica y del Cosmos Universidad de Granada18071 GranadaSpain Instituto Carlos I de Física Téorica y Computacional Facultad de Ciencias18071 GranadaSpain Department of Astronomy Xiamen UniversityXiamen 361005China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n2σ) mean of specific star formation rate (sSFR) enhancement (sSFR_(enh)=0.33±0.07 versus sSFR_(enh)=0.12±0.06) and br... 详细信息

We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index ngalaxies and is nearly constant against the bulge-to-total ratio (B/T).Paired Spirals have a slightly lower fraction of pure disk galaxies (B/T≤0.1) than their counterparts in the control sample.Compared to SFGs with classical bulges,those with pseudobulges have a higher (>2σ) mean of specific star formation rate (sSFR) enhancement (sSFR_(enh)=0.33±0.07 versus sSFR_(enh)=0.12±0.06) and broader scatter (by~1 dex).The eight SFGs that have the highest sSFR_(enh)in the sample all have pseudobulges.A majority (69%) of paired SFGs with strong enhancement (having sSFR more than5 times the median of the control galaxies) have pseudobulges.The Spitzer data show that the pseudobulges in these galaxies are tightly linked to nuclear/circum-nuclear starbursts.Pseudobulge SFGs in S+S and in S+E pairs have significantly (>3σ) different sSFR enhancement,with the means of sSFR_(enh)=0.45±0.08 and-0.04±0.11respectively.We find a decrease in the sSFR enhancements with the density of the environment for SFGs with pseudobulges.Since a high fraction (5/11) of pseudobulge SFGs in S+E pairs are in rich groups/clusters (loca density N_(1Mpc)≥7),the dense environment might be the cause for their low s SFR_(enh).

关键词： galaxies evolution-galaxies interactions-galaxies star formation-galaxies structure-galaxies bulges-galaxies photometry

The Clumpy Structure of Five Star-bursting Dwarf galaxies in the MaNGA Survey

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Research in Astronomy and Astrophysics 2024年第2期24卷 83-103页

作者： Mengting Ju Jun Yin Lei Hao Chenxu Liu Chao-Wei Tsai Junfeng Wang Zhengyi Shao Shuai Feng Yu Rong Key Laboratory for Research in galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China Key Lab for Astrophysics Shanghai 200034China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Astronomy Physics BuildingXiamen UniversityXiamenFujian 361005China College of Physics Hebei Normal UniversityShijiazhuang 050024China Hebei Key Laboratory of Photophysics Research and Application Shijiazhuang 050024China Department of Astronomy University of Science and Technology of ChinaHefei 230026China

The star-forming clumps in star-bursting dwarf galaxies provide valuable insights into understanding the evolution of dwarf galaxies.In this paper,we focus on five star-bursting dwarf galaxies featuring off-centered clumps in the Mapping Nearby galaxies at Apache Point Observatory survey.Using the stellar population synthesis software Fitting Analysis using Differential evolution Optimization,we obtain the spatially resolved distribution of the star formation history,which allows us to construct the g-band images of the five galaxies at different ages.These images can help us to probe the evolution of the morphological structures of these galaxies.While images of a stellar population older than 1 Gyr are typically smooth,images of a stellar population younger than 1 Gyr reveal significant clumps,including multiple clumps which appear at different locations and even different ages.To study the evolutionary connections of these five galaxies to other dwarf galaxies before their star-forming clumps appear,we construct the images of the stellar populations older than three age nodes,and define them to be the images of the"host"galaxies.We find that the properties such as the central surface brightness and the effective radii of the hosts of the five galaxies are in between those of dwarf ellipticals(dEs)and dwarf irregulars(dIrrs),with two clearly more similar to dEs and one more similar to dIrrs.Among the five galaxies,8257-3704 is particularly interesting,as it shows a previous starburst event that is not quite visible from its gri image,but only visible from images of the stellar population at a few hundred million years.The star-forming clump associated with this event may have appeared at around 600 Myr ago and disappeared at around 40 Myr ago.

关键词： galaxies dwarf-galaxies evolution-galaxies formation-Galaxy structure

evolution of Galaxy Types and HI Gas in Hickson Compact Groups

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Research in Astronomy and Astrophysics 2022年第10期22卷 189-201页

作者： Yao Liu Ming Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Compact groups have high galaxy densities and low velocity dispersions,and their group members have experienced numerous and frequent interactions during their lifetimes.They provide a unique environment to study the evolution of galaxies.We examined the galaxies types and H I contents in groups to make a study on the galaxy evolution in compact groups.We used the group crossing time as an age indicator for galaxy groups.Our sample is derived from the Hickson Compact Group catalog.We obtained group morphology data from the Hyper-Leda database and the IR classification based on Wide-Field Infrared Survey Explorer fluxes from Zucker et al.By cross-matching the latest released ALFALFA 100%H I source catalog with supplement by data found in literature,we obtained 40 galaxy groups with H I data available.We confirmed that the weak correlation between H I mass fraction and group crossing time found by Ai&Zhu in SDSS groups also exists in compact groups.We also found that the group spiral galaxy fraction is correlated with the group crossing time,but the actively star-forming galaxy fraction is not correlated with the group crossing time.These results seem to fit with the hypothesis that the sequential acquisition of neighbors from surrounding larger-scale structures has affected the morphology transition and star formation efficiency in compact groups.

关键词： galaxies evolution-galaxies groups general-galaxies ISM

Galaxy Interactions in Filaments and Sheets:Effects of the Large-scale Structures Versus the Local Density

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Research in Astronomy and Astrophysics 2023年第2期23卷 197-204页

作者： Apashanka Das Biswajit Pandey Suman Sarkar Department of Physics Visva-Bharati UniversitySantiniketanBirbhum731235India Department of Physics Indian Institute of Science Education and Research TirupatiTirupati-517507Andhra PradeshIndia

Major interactions are known to trigger star formation in galaxies and alter their color.We study the major interactions in filaments and sheets using SDSS data to understand the influence of large-scale environments on galaxy interactions.We identify the galaxies in filaments and sheets using the local dimension and also find the major pairs residing in these environments.The star formation rate(SFR) and color of the interacting galaxies as a function of pair separation are separately analyzed in filaments and sheets.The analysis is repeated for three volume limited samples covering different magnitude ranges.The major pairs residing in the filaments show a significantly higher SFR and bluer color than those residing in the sheets up to the projected pair separation of~50 kpc.We observe a complete reversal of this behavior for both the SFR and color of the galaxy pairs having a projected separation larger than 50 kpc.Some earlier studies report that the galaxy pairs align with the filament axis.Such alignment inside filaments indicates anisotropic accretion that may cause these differences.We do not observe these trends in the brighter galaxy samples.The pairs in filaments and sheets from the brighter galaxy samples trace relatively denser regions in these environments.The absence of these trends in the brighter samples may be explained by the dominant effect of the local density over the effects of the large-scale environment.

关键词： methods statistical-methods data analysis-galaxies evolution-galaxies interactions-(cosmology:)large-scale structure of universe

Study of Central Intensity Ratio of Seyfert galaxies in Nearby Universe

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Research in Astronomy and Astrophysics 2023年第4期23卷 85-93页

作者： K.T.Vinod C.Baheeja S.Aswathy C.D.Ravikumar Department of Physics University of CalicutMalappuram-673635India Department of Physics Providence Women's CollegeCalicut-673009India

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 conne... 详细信息

We use the recently discovered simple photometric parameter Central Intensity Ratio(CIR)determined for a sample of 57 nearby(zgalaxies 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.

关键词： Galaxy evolution-galaxies active-galaxies photometry-(galaxies:)quasars supermassive black holes-galaxies Seyfert

Merging History of Massive galaxies at 3

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Research in Astronomy and Astrophysics 2023年第1期23卷 100-107页

作者： Kemeng Li Zhen Jiang Ping He Qi Guo Jie Wang College of Physics Jilin UniversityChangchun 130012China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Department of Astronomy Tsinghua UniversityBeijing 100084China Center for High Energy Physics Peking UniversityBeijing 100871China

The observational data of high redshift galaxies become increasingly abundant,especially since the operation of the James Webb Space Telescope,which allows us to verify and optimize the galaxy formation model at high redshifts.In this work,we investigate the merging history of massive galaxies at 3galaxies,also increases from~34%at z=0 to 96%at z=3.Interestingly,almost all major mergers are wet at z>3.This can be attributed to the high fraction(>50%)of cold gas at z>3.In addition,we study some special systems of massive merging galaxies at 3galaxies,but fails to reproduce the relation between the supermassive black hole mass and the dark matter halo mass at z~6.The latter requires more careful estimates of the supermassive black hole masses observationally.Otherwise,it could suggest modifications of the modeling of the supermassive black hole growth at high redshifts.

关键词： galaxies evolution-galaxies formation-galaxies high-redshift-(galaxies:)quasars supermassive black holes

Estimating the Metallicity of Old Star Clusters in M33

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Chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 127-132页

作者： Jun Ma Xu Zhou Hong Wu Jian-Sheng Chen Zhao-Ji Jiang Sui-Jian Xue Jin Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100012

Based on the method proposed by Kong et al. and on the multi-color spectrophotometry by Ma et al., we estimate the metallicities of 16 old star clusters in the nearby spiral galaxy M33, ten of which are halo globular clusters. These old clusters are all metal poor, the range of metallicity ([Fe/H]) is from-0.14 to-2.12. In general, our results are consistent with those derived by other methods, such as integrated spectra and photometry, and our study confirms the reliability of the method of Kong et al.

关键词： galaxies individual(M33)-galaxies evolution-galaxies star clusters

Velocity Dispersion σ_(aper)Aperture Corrections as a Function of Galaxy Properties from Integral-field Stellar Kinematics of 10,000 MaNGA galaxies

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Research in Astronomy and Astrophysics 2023年第8期23卷 53-64页

作者： Kai Zhu Ran Li Xiaoyue Cao Shengdong Lu Michele Cappellari Shude Mao National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Department of Astronomy Tsinghua UniversityBeijing 100084China Sub-department of Astrophysics Department of PhysicsUniversity of OxfordDenys Wilkinson BuildingKeble RoadOxfordOX13RHUK

The second moment of the stellar velocity within the effective radius,denoted by σ^(2)_(e),is a crucial quantity in galaxy studies,as it provides insight into galaxy properties and their mass distributions.However,large spectroscopic surveys typically do not measure σ_(e) directly,instead providing σ_(aper),the second moment of the stellar velocity within a fixed fiber aperture.In this paper,we derive an empirical aperture correction formula,given byσ_(aper)/σ_(e)=(R_(aper)/R_(e))^(α),using spatially resolved stellar kinematics extracted from approximately 10,000 Sloan Digital Sky Survey-Mapping Nearby galaxies at Apache Point Observatory integral field unit observations.Our analysis reveals a strong dependence ofαon the r-band absolute magnitude M_(r),g-i color,and Sérsic index nSer,whereαvalues are lower for brighter,redder galaxies with higher Sérsic indices.Our results demonstrate that the aperture correction derived from previous literature on early-type galaxies cannot be applied to predict the aperture corrections for galaxies with intermediate Sérsic indices.We provide a lookup table ofαvalues for different galaxy types,with parameters in the ranges of-18>M_(r)>-24,0.4

关键词： galaxies evolution-galaxies formation-galaxies kinematics and dynamics-galaxies structure

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 similar.Large samples of the cQGs exhibit a sustained increase in number density from z ~ 3 to 2 and a plateau at 1 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