AIM:To evaluate clinical outcomes following implantation of an extended range of vision intraocular lens(IOL),the ZXR00,and a diffractive multifocal IOL with+2.75 diopters(D)add power,the ZKB00.METHODS:Totally 30 pati...AIM:To evaluate clinical outcomes following implantation of an extended range of vision intraocular lens(IOL),the ZXR00,and a diffractive multifocal IOL with+2.75 diopters(D)add power,the ZKB00.METHODS:Totally 30 patients who underwent either bilateral implantation of the ZXR00 IOL with intended emmetropia(ZXR00 emmetropia group:20 eyes)and intended micromonovision(ZXR00 monovision group:20 eyes),or bilateral implantation of the ZKB00 IOL with intended emmetropia(ZKB00 group:20 eyes)were included in this study.Visual acuity at 4 m,80,and 40 cm;and the types of halos(misty,fine,and rainbow)were analyzed at one and three months after surgery.RESULTS:There were no significant differences in distance visual acuity among the three groups.The mean uncorrected intermediate visual acuity was better in the ZXR00 emmetropia and monovision groups(0.02 logMAR and 0.02 logMAR,respectively)than in the ZKB00 group(0.14 logMAR).The mean uncorrected near visual acuity was worse in the ZXR00 emmetropia group(0.26 logMAR)than in the ZXR00 monovision and ZKB00 groups(0.12 logMAR and 0.10 logMAR,respectively).There was an increased incidence of rainbow halos in the ZKB00 group vs in either ZXR00 group(P=0.033).CONCLUSION:Implantation of the ZXR00 IOL with intended micromonovision provide superior visual acuity than implantation of the ZXR00 IOL with intended emmetropia.The ZXR00 IOLs tend to show a lower incidence of rainbow halos than did the ZKB00 IOL.展开更多
Numerical simulation is an important tool that is helpful for us to understand the process of structure formation in the universe. However, many simulation results of cold dark matter （CDM） halos on a small scale ar...Numerical simulation is an important tool that is helpful for us to understand the process of structure formation in the universe. However, many simulation results of cold dark matter （CDM） halos on a small scale are inconsistent with observations： the central density profile is too cuspy and there are too many substructures, Here we point out that both the problems may be connected with a hitherto unrecognized bias in the simulated halos. Although CDM halos in nature and in simulation are both virialized systems of collisionless CDM particles, gravitational encounter cannot be neglected in the simulated halos because they contain many fewer particles. We demonstrate this by two numerical experiments, showing that there is a difference on the microcosmic scale between the natural and simulated halos. The simulated halo is more akin to globular clusters where gravitational encounter is known to lead to such drastic phenomena as core collapse. Such an artificial core collapse process appears to link the two problems together in the bottom-up scenario of structure formation in the ACDM universe. The discovery of this bias also has implications on the applicability of the Jeans theorem in galactic dynamics.展开更多
Based on the star formation histories of galaxies in halos with different masses, we develop an empirical model to grow galaxies in dark matter halos. This model has very few ingredients, any of which can be associate...Based on the star formation histories of galaxies in halos with different masses, we develop an empirical model to grow galaxies in dark matter halos. This model has very few ingredients, any of which can be associated with observational data and thus be efficiently assessed. By applying this model to a very high resolution cosmological N-body simulation, we predict a number of galaxy properties that are a very good match to relevant observational data. Namely, for both centrals and satellites, the galaxy stellar mass functions up to redshift z=4 and the conditional stellar mass functions in the local universe are in good agreement with observations. In addition, the two point correlation function is well predicted in the different stellar mass ranges explored by our model. Furthermore, after applying stellar population synthesis models to our stellar composition as a function of redshift, we find that the luminosity functions in the 0.1 u,0.19, 0.1r, 0.1i and 0.1z bands agree quite well with the SDSS observational results down to an absolute magnitude at about -17.0. The SDSS conditional luminosity function itself is predicted well. Finally, the cold gas is derived from the star formation rate to predict the HI gas mass within each mock galaxy. We find a remarkably good match to observed HI-to-stellar mass ratios. These features ensure that such galaxy/gas catalogs can be used to generate reliable mock redshift surveys.展开更多
We present an estimate of the strong lensing probability by dark ha-los, withemphasis on the role of the baryonic matter arising purely from radiative cooling. We treat thecontribution of the cooled baryons optimistic...We present an estimate of the strong lensing probability by dark ha-los, withemphasis on the role of the baryonic matter arising purely from radiative cooling. We treat thecontribution of the cooled baryons optimistically with all the cooled baryons confined within acentral core, and including no feedback process from stellar evolution. Our two-component modelprovides a strong lensing probability that is in good agreement with the observed distribution ofmultiple images of quasars, provided that the cooled baryons are deposited within a spherical regionof radius of 0.1 times the virial radius and follow an isothermal profile. It is pointed out thatstrong lensing may be used as an additional probe of baryon physics in dark halos though this maymeanwhile complicate the test of the inner density profiles of dark matter in halos using theobserved strong lensing probability.展开更多
Ultracompact dark matter minihalos （UCMHs） would be formed during the early universe if there were large density perturbations. If dark matter can decay into particles described by the standard model, such as neutri...Ultracompact dark matter minihalos （UCMHs） would be formed during the early universe if there were large density perturbations. If dark matter can decay into particles described by the standard model, such as neutrinos, these objects would become potential astrophysical sources of emission which could be detected by in- struments such as IceCube. In this paper, we investigate neutrino signals from nearby UCMHs due to gravitino dark matter decay and compare these signals with the back- ground neutrino flux which is mainly from the atmosphere to obtain constraints on the abundance of UCMHs.展开更多
We calculate the gravitational lensing probabilities by cold dark matter (CDM) halos with different density profiles, and compare them with current observations from the Cosmic Lens All-Sky Survey (CLASS) and the Jodr...We calculate the gravitational lensing probabilities by cold dark matter (CDM) halos with different density profiles, and compare them with current observations from the Cosmic Lens All-Sky Survey (CLASS) and the Jodrell-Bank VLA Astrometric Survey (JVAS). We find that the lensing probability is dramatically sensitive to the clumping of the dark matter, or quantitatively, the concentration parameter. We also find that our predicted lensing probabilities in most cases show inconsistency with the observations. It is argued that high lensing probability may not be an effective tool for probing the statistical properties of inner structures of dark matter halos.展开更多
The halos that span South africa’s coastline are anything but angelic. Fanning out around four major urban centers-Cape Town, Port Elizabeth, East London and durban-they are made up of innumerable bits and pieces of ...The halos that span South africa’s coastline are anything but angelic. Fanning out around four major urban centers-Cape Town, Port Elizabeth, East London and durban-they are made up of innumerable bits and pieces of plastic. as a form of pollu展开更多
The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large c...The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na2O （K1≥1.2）. Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K2O （K2≥1.2）. Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization： （a） Cu-Au mineralization; （b） W-Mo mineralization; and （c） silicification and potassic metasomatism in the whole ore-forming process. A detailed zonation sequence of indicator elements is obtained using the variability index of indicator elements as follows： Zn→Ag→Cu→Au→W→Mo. According to this zonation, an index such as （Ag＊Zn）D/（Mo×W）D can be constructed and regarded as a significant criterion for predicting the Cu potential at a particular depth.展开更多
The newly discovered neutron halos in the excited states of nuclei 12B, 13C, and 209pb are studied by therelativistic mean-field theory. The calculated binding energies are very close to the experimental ones. The exp...The newly discovered neutron halos in the excited states of nuclei 12B, 13C, and 209pb are studied by therelativistic mean-field theory. The calculated binding energies are very close to the experimental ones. The experimentally extracted root-mean-square radii of the last neutron with different occupations in nuclei are well reproduced bycalculations. New candidates for the neutron halos in excited states are predicted and are useful for further search ofneutron halos in the excited states of stable nuclei.展开更多
We have accurately evaluated the halo pairwise velocity dispersion and the halo mean streaming velocity in the LCDM model (the fiat ω0 = 0.3 model) using a set of high-resolution N-body simulations. Based on the simu...We have accurately evaluated the halo pairwise velocity dispersion and the halo mean streaming velocity in the LCDM model (the fiat ω0 = 0.3 model) using a set of high-resolution N-body simulations. Based on the simulation results, we have developed a model for the pairwise velocity dispersion of halos. Our model agrees with the simulation results over all scales we studied. We have also tested the model of Sheth et al. for the mean streaming motion of halos derived from the pair-conservation equation. We found that their model reproduces the simulation data very well on large scale, but under-predicts the streaming motion on scales r < 10 h-1 Mpc. We have introduced an empirical relation to improve their model. These improved models are useful for predicting the redshift correlation functions and the redshift power spectrum of galaxies if the halo occupation number model, e.g. the cluster weighted model, is given for the galaxies.展开更多
Article devoted to searching the parameters of dark matter halos on the base of dwarf galaxies’ dynamics (Messier 32 and Leo I). For doing this, we propose the new approach founded on construction the coupled ellipti...Article devoted to searching the parameters of dark matter halos on the base of dwarf galaxies’ dynamics (Messier 32 and Leo I). For doing this, we propose the new approach founded on construction the coupled elliptical trajectory for a probe body in the gravitational fields of Newtonian potential and potential of dark matter’s halo. This allows more accuracy estimate its central density for the Navarro-Frenk-White profile and free parameter for the Einasto profile . Our result is in good correlation with results of other authors that are got by different numerical methods.展开更多
Using a semi-analytic approach,we estimate halo spins for a large sample of H I-rich galaxies from the Arecibo Legacy Fast ALFA Survey and examine the correlation between H I mass fractions and halo spins.Our analysis...Using a semi-analytic approach,we estimate halo spins for a large sample of H I-rich galaxies from the Arecibo Legacy Fast ALFA Survey and examine the correlation between H I mass fractions and halo spins.Our analysis reveals a strong correlation between halo spin and the H I-to-stellar mass ratio in both low-mass and massive galaxy samples.This finding suggests a universal formation scenario:higher halo spin reduces angular momentum loss and gas condensation,leading to lower star formation rates and weaker feedback,which in turn help retain gas within dark matter halos.展开更多
Leveraging the semi-analytic method,we compute halo spins for a substantial sample of H I-bearing galaxies observed in the Arecibo Legacy Fast ALFA Survey.Our statistical analysis reveals a correlation between halo sp...Leveraging the semi-analytic method,we compute halo spins for a substantial sample of H I-bearing galaxies observed in the Arecibo Legacy Fast ALFA Survey.Our statistical analysis reveals a correlation between halo spin and environment,although the trend is subtle.On average,galaxies exhibit a decreasing halo spin tendency in denser environments.This observation contrasts with previous results from N-body simulations in the Lambda Cold Dark Matter framework.The discrepancy may be attributed to environmental gas stripping,leading to an underestimation of halo spins in galaxies in denser environments,or to baryonic processes that significantly alter the original dark matter halo spins,deviating from previous N-body simulation findings.展开更多
We analyze the absorption features in the public 73 ks XMM-Newton spectra of the Seyfert 1 galaxy PG 0052+251.Our analysis reveals the presence of a warm absorber(WA)intrinsic to the source and the hot circumgalactic ...We analyze the absorption features in the public 73 ks XMM-Newton spectra of the Seyfert 1 galaxy PG 0052+251.Our analysis reveals the presence of a warm absorber(WA)intrinsic to the source and the hot circumgalactic medium at zero redshift.The identified WA is inflowing toward the central black hole,with a velocity shift of■.The ionization parameter of the WA is■,showing strong O II and O III absorption lines,along with a significant absorption of the spectral continuum at?10?.The line of sight toward PG 0052+251 intersects the halo of M31 at an impact parameter of approximately 218 kpc.Several local(z~0)absorption lines,like O VII,O VIII,and Ne IX,were detected.The derived hydrogen column density of the local hot gas is 2.2–2.6σhigher than those estimated by several models of the Galactic hot halo,suggesting a likely contribution from the M31 halo.We also find two absorption features at24.305?and 21.410?,which are unlikely to be associated with the hot halos or the warm-hot intergalactic medium but imply the presence of an additional WA component with an outflow velocity of approximately-7000 km s^(-1).展开更多
The correlation between atmospheric gravity waves(GWs) and Transient Luminous Events(TLEs) has been poorly studied using both synchronous observations and numerical simulations. To investigate the modulation effects o...The correlation between atmospheric gravity waves(GWs) and Transient Luminous Events(TLEs) has been poorly studied using both synchronous observations and numerical simulations. To investigate the modulation effects of GWs on TLEs,a troposphere-mesosphere quasi-electrostatic field model is developed in three-dimensional Cartesian coordinates, and the effects of GW perturbations on the initiation and optical emissions of sprite halos are simulated using the model. Simulation results indicate that the atmospheric density at lower ionosphere altitudes becomes inhomogeneous due to GW perturbations, and sprite halos tend to initiate in the GW troughs due to the lower electric breakdown threshold. GW perturbations cause the deformation of sprite halos, strong luminous regions distribute mainly along the GW troughs while optical intensities along the GW peaks is relatively weak. Larger GW perturbations lead to more pronounced deformation of sprite halos, however, stronger lightning discharges in the troposphere result in less optical perturbations of sprite halos. The observed luminous intensities and optical morphology of sprite halos are also affected by the observing orientations and the lightning polarities.展开更多
In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the...In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the DM halo parameter and the cloud string parameter affect BH attributes such as quasinormal modes(QNMs)and shadow cast.To do this,we first look into the effective potential of perturbation equations for three types of perturbation fields with different spins:massless scalar field,electromagnetic field and gravitational field.Then,using the sixth-order Wentzel-Kramers-Brillouin approximation,we examine QNMs of the BH disturbed by the three fields and derive quasinormal frequencies.The changes in QNM versus the core density parameter and the cloud string parameter for three disturbances are explored.We also investigate how the core density and the cloud string parameter affect the photon sphere and shadow radius.Interestingly,the study shows that the influence of Dehnen-type DM and cloud strings increases both the photon sphere and the shadow radius.Finally,we employ observational data from Sgr A^(*) and M87^(*) to set limitations on the BH parameters.展开更多
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(No.2018R1C1B6002794)Korea University Grant(No.K1625491,No.K1722121,No.K1811051)。
文摘AIM:To evaluate clinical outcomes following implantation of an extended range of vision intraocular lens(IOL),the ZXR00,and a diffractive multifocal IOL with+2.75 diopters(D)add power,the ZKB00.METHODS:Totally 30 patients who underwent either bilateral implantation of the ZXR00 IOL with intended emmetropia(ZXR00 emmetropia group:20 eyes)and intended micromonovision(ZXR00 monovision group:20 eyes),or bilateral implantation of the ZKB00 IOL with intended emmetropia(ZKB00 group:20 eyes)were included in this study.Visual acuity at 4 m,80,and 40 cm;and the types of halos(misty,fine,and rainbow)were analyzed at one and three months after surgery.RESULTS:There were no significant differences in distance visual acuity among the three groups.The mean uncorrected intermediate visual acuity was better in the ZXR00 emmetropia and monovision groups(0.02 logMAR and 0.02 logMAR,respectively)than in the ZKB00 group(0.14 logMAR).The mean uncorrected near visual acuity was worse in the ZXR00 emmetropia group(0.26 logMAR)than in the ZXR00 monovision and ZKB00 groups(0.12 logMAR and 0.10 logMAR,respectively).There was an increased incidence of rainbow halos in the ZKB00 group vs in either ZXR00 group(P=0.033).CONCLUSION:Implantation of the ZXR00 IOL with intended micromonovision provide superior visual acuity than implantation of the ZXR00 IOL with intended emmetropia.The ZXR00 IOLs tend to show a lower incidence of rainbow halos than did the ZKB00 IOL.
文摘Numerical simulation is an important tool that is helpful for us to understand the process of structure formation in the universe. However, many simulation results of cold dark matter （CDM） halos on a small scale are inconsistent with observations： the central density profile is too cuspy and there are too many substructures, Here we point out that both the problems may be connected with a hitherto unrecognized bias in the simulated halos. Although CDM halos in nature and in simulation are both virialized systems of collisionless CDM particles, gravitational encounter cannot be neglected in the simulated halos because they contain many fewer particles. We demonstrate this by two numerical experiments, showing that there is a difference on the microcosmic scale between the natural and simulated halos. The simulated halo is more akin to globular clusters where gravitational encounter is known to lead to such drastic phenomena as core collapse. Such an artificial core collapse process appears to link the two problems together in the bottom-up scenario of structure formation in the ACDM universe. The discovery of this bias also has implications on the applicability of the Jeans theorem in galactic dynamics.
基金supported by the 973 Program(No.2015CB857002)the National Natural Science Foundation of China(Grant Nos.11203054,11128306,11121062,11233005,11073017and 11421303)+2 种基金NCET-11-0879,the Strategic Priority Research Program“The Emergence of Cosmological Structures”of the Chinese Academy of Sciences,Grant No.XDB09000000the Shanghai Committee of Science and Technology,China(Grant No.12ZR1452800)supported by the High Performance Computing Resource in the Core Facility for Advanced Research Computing at Shanghai Astronomical Observatory
文摘Based on the star formation histories of galaxies in halos with different masses, we develop an empirical model to grow galaxies in dark matter halos. This model has very few ingredients, any of which can be associated with observational data and thus be efficiently assessed. By applying this model to a very high resolution cosmological N-body simulation, we predict a number of galaxy properties that are a very good match to relevant observational data. Namely, for both centrals and satellites, the galaxy stellar mass functions up to redshift z=4 and the conditional stellar mass functions in the local universe are in good agreement with observations. In addition, the two point correlation function is well predicted in the different stellar mass ranges explored by our model. Furthermore, after applying stellar population synthesis models to our stellar composition as a function of redshift, we find that the luminosity functions in the 0.1 u,0.19, 0.1r, 0.1i and 0.1z bands agree quite well with the SDSS observational results down to an absolute magnitude at about -17.0. The SDSS conditional luminosity function itself is predicted well. Finally, the cold gas is derived from the star formation rate to predict the HI gas mass within each mock galaxy. We find a remarkably good match to observed HI-to-stellar mass ratios. These features ensure that such galaxy/gas catalogs can be used to generate reliable mock redshift surveys.
基金Supported by the National Natural Science Foundation of China.
文摘We present an estimate of the strong lensing probability by dark ha-los, withemphasis on the role of the baryonic matter arising purely from radiative cooling. We treat thecontribution of the cooled baryons optimistically with all the cooled baryons confined within acentral core, and including no feedback process from stellar evolution. Our two-component modelprovides a strong lensing probability that is in good agreement with the observed distribution ofmultiple images of quasars, provided that the cooled baryons are deposited within a spherical regionof radius of 0.1 times the virial radius and follow an isothermal profile. It is pointed out thatstrong lensing may be used as an additional probe of baryon physics in dark halos though this maymeanwhile complicate the test of the inner density profiles of dark matter in halos using theobserved strong lensing probability.
基金Supported by the National Natural Science Foundation of China
文摘Ultracompact dark matter minihalos （UCMHs） would be formed during the early universe if there were large density perturbations. If dark matter can decay into particles described by the standard model, such as neutrinos, these objects would become potential astrophysical sources of emission which could be detected by in- struments such as IceCube. In this paper, we investigate neutrino signals from nearby UCMHs due to gravitino dark matter decay and compare these signals with the back- ground neutrino flux which is mainly from the atmosphere to obtain constraints on the abundance of UCMHs.
基金This work was partially supported by the National Natural Science Foundation of China under Grant No. 10003002.
文摘We calculate the gravitational lensing probabilities by cold dark matter (CDM) halos with different density profiles, and compare them with current observations from the Cosmic Lens All-Sky Survey (CLASS) and the Jodrell-Bank VLA Astrometric Survey (JVAS). We find that the lensing probability is dramatically sensitive to the clumping of the dark matter, or quantitatively, the concentration parameter. We also find that our predicted lensing probabilities in most cases show inconsistency with the observations. It is argued that high lensing probability may not be an effective tool for probing the statistical properties of inner structures of dark matter halos.
文摘The halos that span South africa’s coastline are anything but angelic. Fanning out around four major urban centers-Cape Town, Port Elizabeth, East London and durban-they are made up of innumerable bits and pieces of plastic. as a form of pollu
基金supported by the National High Technology Research and Development Program of China (No 2006AA06Z113)the National Natural Science Foundation of China (No. 40772197)
文摘The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na2O （K1≥1.2）. Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K2O （K2≥1.2）. Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization： （a） Cu-Au mineralization; （b） W-Mo mineralization; and （c） silicification and potassic metasomatism in the whole ore-forming process. A detailed zonation sequence of indicator elements is obtained using the variability index of indicator elements as follows： Zn→Ag→Cu→Au→W→Mo. According to this zonation, an index such as （Ag＊Zn）D/（Mo×W）D can be constructed and regarded as a significant criterion for predicting the Cu potential at a particular depth.
文摘The newly discovered neutron halos in the excited states of nuclei 12B, 13C, and 209pb are studied by therelativistic mean-field theory. The calculated binding energies are very close to the experimental ones. The experimentally extracted root-mean-square radii of the last neutron with different occupations in nuclei are well reproduced bycalculations. New candidates for the neutron halos in excited states are predicted and are useful for further search ofneutron halos in the excited states of stable nuclei.
基金the National Natural Science Foundation of China.
文摘We have accurately evaluated the halo pairwise velocity dispersion and the halo mean streaming velocity in the LCDM model (the fiat ω0 = 0.3 model) using a set of high-resolution N-body simulations. Based on the simulation results, we have developed a model for the pairwise velocity dispersion of halos. Our model agrees with the simulation results over all scales we studied. We have also tested the model of Sheth et al. for the mean streaming motion of halos derived from the pair-conservation equation. We found that their model reproduces the simulation data very well on large scale, but under-predicts the streaming motion on scales r < 10 h-1 Mpc. We have introduced an empirical relation to improve their model. These improved models are useful for predicting the redshift correlation functions and the redshift power spectrum of galaxies if the halo occupation number model, e.g. the cluster weighted model, is given for the galaxies.
文摘Article devoted to searching the parameters of dark matter halos on the base of dwarf galaxies’ dynamics (Messier 32 and Leo I). For doing this, we propose the new approach founded on construction the coupled elliptical trajectory for a probe body in the gravitational fields of Newtonian potential and potential of dark matter’s halo. This allows more accuracy estimate its central density for the Navarro-Frenk-White profile and free parameter for the Einasto profile . Our result is in good correlation with results of other authors that are got by different numerical methods.
基金support from the National Natural Science Foundation of China(NSFC)grant 12273037the CAS Pioneer Hundred Talents Program(Category B)+1 种基金the USTC Research Funds of the Double First-Class Initiativesupported by the China Manned Space Program with grant No.CMS-CSST-2025-A06 and CMS-CSST-2025-A08.
文摘Using a semi-analytic approach,we estimate halo spins for a large sample of H I-rich galaxies from the Arecibo Legacy Fast ALFA Survey and examine the correlation between H I mass fractions and halo spins.Our analysis reveals a strong correlation between halo spin and the H I-to-stellar mass ratio in both low-mass and massive galaxy samples.This finding suggests a universal formation scenario:higher halo spin reduces angular momentum loss and gas condensation,leading to lower star formation rates and weaker feedback,which in turn help retain gas within dark matter halos.
基金supports from the CAS Pioneer Hundred Talents Program(Category B)the National Natural Science Foundation of China(NSFC,grant No.12273037)the USTC Research Funds of the Double First-Class Initiative。
文摘Leveraging the semi-analytic method,we compute halo spins for a substantial sample of H I-bearing galaxies observed in the Arecibo Legacy Fast ALFA Survey.Our statistical analysis reveals a correlation between halo spin and environment,although the trend is subtle.On average,galaxies exhibit a decreasing halo spin tendency in denser environments.This observation contrasts with previous results from N-body simulations in the Lambda Cold Dark Matter framework.The discrepancy may be attributed to environmental gas stripping,leading to an underestimation of halo spins in galaxies in denser environments,or to baryonic processes that significantly alter the original dark matter halo spins,deviating from previous N-body simulation findings.
基金supported by the National Natural Science Foundation of China under Nos.11890692,12133008 and 12221003We acknowledge the science research grant from the China Manned Space Project with No.CMS-CSST-2021-A04.
文摘We analyze the absorption features in the public 73 ks XMM-Newton spectra of the Seyfert 1 galaxy PG 0052+251.Our analysis reveals the presence of a warm absorber(WA)intrinsic to the source and the hot circumgalactic medium at zero redshift.The identified WA is inflowing toward the central black hole,with a velocity shift of■.The ionization parameter of the WA is■,showing strong O II and O III absorption lines,along with a significant absorption of the spectral continuum at?10?.The line of sight toward PG 0052+251 intersects the halo of M31 at an impact parameter of approximately 218 kpc.Several local(z~0)absorption lines,like O VII,O VIII,and Ne IX,were detected.The derived hydrogen column density of the local hot gas is 2.2–2.6σhigher than those estimated by several models of the Galactic hot halo,suggesting a likely contribution from the M31 halo.We also find two absorption features at24.305?and 21.410?,which are unlikely to be associated with the hot halos or the warm-hot intergalactic medium but imply the presence of an additional WA component with an outflow velocity of approximately-7000 km s^(-1).
基金supported by the National Key Research and Development Plan(Grant No.2017YFC1501505)the National Natural Science Foundation of China(Grant No.41775006)
文摘The correlation between atmospheric gravity waves(GWs) and Transient Luminous Events(TLEs) has been poorly studied using both synchronous observations and numerical simulations. To investigate the modulation effects of GWs on TLEs,a troposphere-mesosphere quasi-electrostatic field model is developed in three-dimensional Cartesian coordinates, and the effects of GW perturbations on the initiation and optical emissions of sprite halos are simulated using the model. Simulation results indicate that the atmospheric density at lower ionosphere altitudes becomes inhomogeneous due to GW perturbations, and sprite halos tend to initiate in the GW troughs due to the lower electric breakdown threshold. GW perturbations cause the deformation of sprite halos, strong luminous regions distribute mainly along the GW troughs while optical intensities along the GW peaks is relatively weak. Larger GW perturbations lead to more pronounced deformation of sprite halos, however, stronger lightning discharges in the troposphere result in less optical perturbations of sprite halos. The observed luminous intensities and optical morphology of sprite halos are also affected by the observing orientations and the lightning polarities.
基金supported by the National Natural Science Foundation of China under Grant No.11675143the National Key Research and Development Program of China under Grant No.2020YFC2201503。
文摘In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the DM halo parameter and the cloud string parameter affect BH attributes such as quasinormal modes(QNMs)and shadow cast.To do this,we first look into the effective potential of perturbation equations for three types of perturbation fields with different spins:massless scalar field,electromagnetic field and gravitational field.Then,using the sixth-order Wentzel-Kramers-Brillouin approximation,we examine QNMs of the BH disturbed by the three fields and derive quasinormal frequencies.The changes in QNM versus the core density parameter and the cloud string parameter for three disturbances are explored.We also investigate how the core density and the cloud string parameter affect the photon sphere and shadow radius.Interestingly,the study shows that the influence of Dehnen-type DM and cloud strings increases both the photon sphere and the shadow radius.Finally,we employ observational data from Sgr A^(*) and M87^(*) to set limitations on the BH parameters.
