We estimate halo spins for H I-rich galaxies in the Arecibo Legacy Fast ALFA survey using a semi-analytic approach,examining the relationship between halo spin and stellar surface density.Our findings reveal an invers...We estimate halo spins for H I-rich galaxies in the Arecibo Legacy Fast ALFA survey using a semi-analytic approach,examining the relationship between halo spin and stellar surface density.Our findings reveal an inverse correlation in both low-and high-mass galaxy samples,with stellar surface density decreasing as halo spin increases.This trend highlights the pivotal role of halo spin in galaxy evolution and suggests a universal formation scenario:high-spin halos,accompanied by high-spin accreted gas,retain angular momentum,preventing gas from efficiently condensing in the galactic center and thus suppressing star formation.Consequently,weak feedback redistributes gas to the halo outskirts without significant expulsion.The shallower central gravitational potential in high-spin halos promotes outward stellar migration,leading to more extended stellar distributions and lower stellar surface densities.展开更多
We analyze the galaxy pairs in a set of volume limited samples from the Sloan Digital Sky Survey to study the effects of minor interactions on the star formation rate(SFR)and color of galaxies.We carefully design cont...We analyze the galaxy pairs in a set of volume limited samples from the Sloan Digital Sky Survey to study the effects of minor interactions on the star formation rate(SFR)and color of galaxies.We carefully design control samples of isolated galaxies by matching the stellar mass and redshift of the minor pairs.The SFR distributions and color distributions in the minor pairs differ from their controls at>99%significance level.We also simultaneously match the control galaxies in stellar mass,redshift and local density to assess the role of the environment.The null hypothesis can be rejected at>99%confidence level even after matching the environment.Our analysis shows a quenching in the minor pairs where the degree of quenching decreases with the increasing pair separation and plateaus beyond 50 kpc.We also prepare a sample of minor pairs with Hαline information.We calculate the SFR of these galaxies using the Hαline and repeat our analysis.We observe a quenching in the Hαsample too.We find that the majority of the minor pairs are quiescent systems that could be quenched due to minor interactions.Combining data from the Galaxy Zoo and Galaxy Zoo 2,we find that only∼1%galaxies have a dominant bulge,4%–7%galaxies host a bar and 5%–10%of galaxies show active galactic nucleus(AGN)activity in minor pairs.This indicates that the presence of bulge,bar or AGN activity plays an insignificant role in quenching the galaxies in minor pairs.The more massive companion satisfies the criteria for mass quenching in most of the minor pairs.We propose that the stripping and starvation likely caused the quenching in the less massive companion at a later stage of evolution.展开更多
基金supports from the CAS Pioneer Hundred Talents Program (Category B)the National Natural Science Foundation of China (NSFC, grant No. 12273037)+2 种基金Funds of the Double First-Class Initiativesupported by the research grants from the China Manned Space Project (the second-stage CSST science projects:“Investigation of small-scale structures in galaxies and forecasting of observations” and “CSST study on specialized galaxies in ultraviolet and multi-band”)supported by the China Postdoctoral Science Foundation grant No. 2024M763213
文摘We estimate halo spins for H I-rich galaxies in the Arecibo Legacy Fast ALFA survey using a semi-analytic approach,examining the relationship between halo spin and stellar surface density.Our findings reveal an inverse correlation in both low-and high-mass galaxy samples,with stellar surface density decreasing as halo spin increases.This trend highlights the pivotal role of halo spin in galaxy evolution and suggests a universal formation scenario:high-spin halos,accompanied by high-spin accreted gas,retain angular momentum,preventing gas from efficiently condensing in the galactic center and thus suppressing star formation.Consequently,weak feedback redistributes gas to the halo outskirts without significant expulsion.The shallower central gravitational potential in high-spin halos promotes outward stellar migration,leading to more extended stellar distributions and lower stellar surface densities.
基金financial support from the SERB,DST,Government of India through the project CRG/2019/001110IUCAA,Pune for providing support through an associateship program+8 种基金IISER Tirupati for support through a postdoctoral fellowshipFunding for the SDSS and SDSS-II has been provided by the Alfred P.Sloan Foundationthe Participating Institutionsthe National Science Foundationthe U.S.Department of Energythe National Aeronautics and Space Administrationthe Japanese Monbukagakushothe Max Planck Societythe Higher Education Funding Council for England.
文摘We analyze the galaxy pairs in a set of volume limited samples from the Sloan Digital Sky Survey to study the effects of minor interactions on the star formation rate(SFR)and color of galaxies.We carefully design control samples of isolated galaxies by matching the stellar mass and redshift of the minor pairs.The SFR distributions and color distributions in the minor pairs differ from their controls at>99%significance level.We also simultaneously match the control galaxies in stellar mass,redshift and local density to assess the role of the environment.The null hypothesis can be rejected at>99%confidence level even after matching the environment.Our analysis shows a quenching in the minor pairs where the degree of quenching decreases with the increasing pair separation and plateaus beyond 50 kpc.We also prepare a sample of minor pairs with Hαline information.We calculate the SFR of these galaxies using the Hαline and repeat our analysis.We observe a quenching in the Hαsample too.We find that the majority of the minor pairs are quiescent systems that could be quenched due to minor interactions.Combining data from the Galaxy Zoo and Galaxy Zoo 2,we find that only∼1%galaxies have a dominant bulge,4%–7%galaxies host a bar and 5%–10%of galaxies show active galactic nucleus(AGN)activity in minor pairs.This indicates that the presence of bulge,bar or AGN activity plays an insignificant role in quenching the galaxies in minor pairs.The more massive companion satisfies the criteria for mass quenching in most of the minor pairs.We propose that the stripping and starvation likely caused the quenching in the less massive companion at a later stage of evolution.
