We analyzed the relationship between several basic parameters describing supermassive black holes such as jet power,black hole spin,accretion disk magnetic field,black hole mass,etc.We found that there is a general co...We analyzed the relationship between several basic parameters describing supermassive black holes such as jet power,black hole spin,accretion disk magnetic field,black hole mass,etc.We found that there is a general correlation between these parameters,such as jet power is significantly positively correlated with black hole spin,while black hole mass is significantly negatively correlated with black hole spin.To apprehend these relationships,we consider the Blandford–Znajek model to be superior to the Blandford–Payne model.It is also found that the intrinsic gamma luminosity of the FSRQs has a positive correlation with the accretion disk magnetic field,while the intrinsic gamma luminosity of the BL Lacs has a negative correlation with the accretion disk magnetic field.A feedback effect may exist between accretion disk accretion rate and magnetic field,which may be the key to the evolution between BL Lacs and FSRQs.There is no significant difference in the jet power and jet generation efficiency of FSRQs and BL Lacs,which suggests that the jets are generated by the same mechanism.The contribution rate of accretion rate to jet generation efficiency is high,while the contribution rate of accretion rate to jet power is very low.展开更多
This paper is a further elaboration of the author’s Time Dilation Cosmology (TDC) holographic model that ties gravitation and celestial mechanics and kinematics directly to time dilation, resolving all the major conu...This paper is a further elaboration of the author’s Time Dilation Cosmology (TDC) holographic model that ties gravitation and celestial mechanics and kinematics directly to time dilation, resolving all the major conundrums in astrophysics, and ties astrophysics directly to quantum physics. It begins with a brief summary of the TDC model and contains the new derivation for the time dilation version of the formula for summing relativistic velocities, Einstein’s gravitational constant and the time dilation versions for the Lorentz factor and the Euclidean norm of the 3d velocity vector, the two of which can then be used in the Four-velocity formula. It is demonstrated how orbital curvature is manifested as the resultant of two time dilation-manifested velocities. It also explains why an interferometer cannot distinguish free fall from zero gravity and further elaborates on the author’s previous explanations of how spiral galaxies are formed, and contains mathematical proof that Black Holes are actually Magnetospheric Eternally Collapsing Objects (MECOs) that are massless spacetime vortices.展开更多
Environments play an important role in galaxy formation and evolution,particularly in regulating the content of neutral gas.However,current HI surveys have limitations in their depth,which prevents them from adequatel...Environments play an important role in galaxy formation and evolution,particularly in regulating the content of neutral gas.However,current HI surveys have limitations in their depth,which prevents them from adequately studying low HI content galaxies in high-density regions.In this study,we address this issue by employing the Five-hundred-meter Aperture Spherical radio Telescope with extensive integration times to complement the relatively shallow Arecibo Legacy Fast Arecibo L-band Feed Array HI survey.This approach allows us to explore the gas content of dwarf galaxies across various environments.We observe a positive relationship between HI mass and stellar mass in dwarf galaxies,with a well-defined upper boundary for HI mass that holds true in both observations and simulations.Furthermore,we find a decrease in the H I-to-stellar mass ratio(M_(HI)/M_*)as the density of the environment increases,irrespective of whether it is determined by the proximity to the nearest group or the projected number density.Comparing our observations to simulations,we note a steeper slope in the relationship,indicating a gradual gas-stripping process in the observational data.Additionally,we find that the scaling relation between the M_(HI)/M_*and optical properties can be improved by incorporating galaxy environments.展开更多
We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium,active galactic nuclei(AGN)feedback and black hole(BH)feeding in a massive c...We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium,active galactic nuclei(AGN)feedback and black hole(BH)feeding in a massive compact galaxy,with an emphasis on the impact of different central BH masses.We find that with a more massive central BH,high-speed outflows are more prominent,and the gas fraction in the compact galaxy is reduced.Due to the lower gas density and higher gas temperature,the compact galaxy with a more massive BH(MAS galaxy)remains predominantly single-phase with the cooling time t_(cool)■100t_(ff).In contrast,the compact galaxy with the reference BH mass(REF galaxy)maintains a higher gas fraction with a shorter cooling time,slightly more multiphase gas and less prominent outflows.We further demonstrate that the difference in gas thermal states and kinematics is caused by the stronger AGN feedback in the compact galaxy with a more massive BH,where the AGN wind power is twice as much as that with the reference BH.Since the AGN feedback efficiently suppresses the inflow rate and the BH feeding rate,the BH mass growth is significant in neither the compact galaxy with the reference BH nor that with the more massive BH,only by 24%and 11%of the initial BH mass,respectively,over the entire evolution time of 10 Gyr.We thus posit that without ex situ mass supply from mergers,the massive BHs in compact galaxies cannot grow significantly via gas accretion during the late phase,but might have already formed by the end of the rapid early phase of galaxy formation.展开更多
This model ties gravitation and celestial mechanics and kinematics directly to time dilation. It is a new theory of cosmology and the evolution of galaxies. Space and time are not two separate things, but two aspects ...This model ties gravitation and celestial mechanics and kinematics directly to time dilation. It is a new theory of cosmology and the evolution of galaxies. Space and time are not two separate things, but two aspects of a single thing, “spacetime”. Whatever affects space, affects time, and vice-versa. If time speeds up, space must contract to maintain the speed of light, c, and when space thickens into a mass, it is harder to evolve forward, and time appears to slow. If spatial events are spinning as time passes, then the forward direction of time is spinning. This is Einstein’s curvature in the forward direction of time. Herein, the basis is outlined for time dilation cosmology in a spacetime/quantum continuum, including the time dilation-based derivation of the mass of the Cosmic Microwave Background Radiation (CMBR), and time dilation formulas are derived for stellar system orbital, and galactic rotation, velocities, the force in time in Newtons, the Hamiltonian, the Hubble shift, the empirical gravitational constant, G, and other formulas, showing their direct relationship to the difference in the rate of time between the far distant observer’s invariant 1 s/s rate of time and the slower rate of time at the coordinate point, proving the universe is not composed of separate bodies moving through space, but is an evolving 3-dimensional holographic continuum containing varying densities evolving forward in the forward direction of time, the 4th dimension, at apparently different rates of time, the velocities merely being compensation for those slower rates of time in a continuum evolving forward overall at c, which is why light propagates at c, even from a moving source. As per General Relativity, if there is no rate of time difference between coordinate points, there is no gravitational attraction between those points, and no gravitationally induced velocity. This model resolves all the major conundrums in astrophysics, eliminating Dark Energy and Dark Matter, and ties astrophysics directly to quantum p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
We study the color and star formation rates of paired galaxies in filaments and sheets using the EAGLE simulations.We find that the major pairs with pair separation<50 kpc are bluer and more star-forming in filamen...We study the color and star formation rates of paired galaxies in filaments and sheets using the EAGLE simulations.We find that the major pairs with pair separation<50 kpc are bluer and more star-forming in filamentary environments compared to those hosted in sheet-like environments.This trend reverses beyond a pair separation of~50 kpc.The interacting pairs with larger separations(>50 kpc)in filaments are on average redder and low-star-forming compared to those embedded in sheets.The galaxies in filaments and sheets may have different stellar mass and cold gas mass distributions.Using a KS test,we find that for paired galaxies with pair separation<50 kpc,there are no significant differences in these properties in sheets and filaments.The filaments transport gas toward the cluster of galaxies.Some earlier studies find preferential alignment of galaxy pairs with the filament axis.Such alignment of galaxy pairs may lead to different gas accretion efficiency in galaxies residing in filaments and sheets.We propose that the enhancement of star formation rate at smaller pair separation in filaments is caused by the alignment of galaxy pairs.A recent study with SDSS data reports the same findings.The confirmation of these results by the EAGLE simulations suggests that the hydrodynamical simulations are powerful theoretical tools for studying galaxy formation and evolution in the cosmic web.展开更多
We present a study of a fossil cluster,SDSS J0150–1005（z 0.364）,with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric...We present a study of a fossil cluster,SDSS J0150–1005（z 0.364）,with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent merger.According to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±11.The central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar temperatures.Our results indicate that SDSS J0150–1005 formed during an early epoch.展开更多
In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements wit...In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements with theoretical stellar population synthesis models of Bruzual & Charlot. Also, we calculate the mass of these star clusters using the theoretical M/LV ratio. The results show that, these star clusters formed continuously in M33 from ~ 7 × 10<SUP>6</SUP>–10<SUP>10</SUP> years and have masses between ~ 10<SUP>3</SUP> and 2 × 10<SUP>6</SUP>M<SUB>☉</SUB>. M33 frames were observed as a part of the BATC Multicolor Survey of the sky in 13 intermediate-band filters from 3800 to 10 000?. The relation between age and mass confirms that the sample star cluster masses systematically decrease from the oldest to the youngest.展开更多
Based on the large field multicolor observations ofBeijing-Arizona-Taiwan-Connecticut (BATC) program, we obtain the spectral energy distribution (SED)for individual regions of M81. We study the structure and evolution...Based on the large field multicolor observations ofBeijing-Arizona-Taiwan-Connecticut (BATC) program, we obtain the spectral energy distribution (SED)for individual regions of M81. We study the structure and evolution of M81 with an evolutionarypopulation synthesis (EPS) model, PEGASE. We find that the exponentially deceasing star formationrate (SFR) with star formation scale 3 Gyr (hereafter Exp, τ = 3 Gyr) gives the best agreementbetween the model predictions and the observed SEDs. We then obtain the structure, age distributionand evolutionary history of M81. There is a clear age gradient between the central and outerregions. The populations in the central regions are older than 7 Gyr, those in the outer regions areyounger, at about 4.5 Gyr. The youngest components in the spiral arms have ages of about 2.5 Gyr orless.展开更多
There are significant correlations between the broad line region luminosity LBLR,the quantity Δmax(maximum of Δ≡log[(Fν)cm/(Fν)mm]) and redshift z.There are strong correlations between the extended radio luminosi...There are significant correlations between the broad line region luminosity LBLR,the quantity Δmax(maximum of Δ≡log[(Fν)cm/(Fν)mm]) and redshift z.There are strong correlations between the extended radio luminosity PE,LBLR and Δmax.Our results indicate that FSRQs with higher mass accretion rate M and black hole spin j occur in the earlier,highly luminous,violent phase of the galactic sequence,and BL Lacs with lower M and j occur in the lower luminous,later phase of the galactic sequence,while FR II BL Lacs are possible intermediate stages in the sequence of blazars from FSRQs to FR I BL Lacs with j lower than FR II BL Lacs.It is indicated that there is a disk-jet symbiosis in blazars.展开更多
Using a sample of 13 early-type spiral galaxies hosting nuclear rings,we report remarkable correlations between the properties of the nuclear rings and the central intensity ratio(CIR) of their host galaxies.The CIR,a...Using a sample of 13 early-type spiral galaxies hosting nuclear rings,we report remarkable correlations between the properties of the nuclear rings and the central intensity ratio(CIR) of their host galaxies.The CIR,a function of intensity of light within the central 1.5 and 3 arcsec region,is found to be a vital parameter in galaxy evolution,as it shares strong correlations with many structural and dynamical properties of early-type galaxies,including mass of the central supermassive black hole(SMBH).We use archival HST images for aperture photometry at the centre of the galaxy image to compute the CIR.We observe that the relative sizes of nuclear rings and ring cluster surface densities strongly correlate with the CIR.These correlations suggest reduced star formation in the centres of galaxies hosting small and dense nuclear rings.This scenario appears to be a consequence of strong bars as advocated by the significant connection observed between the CIR and bar strengths.In addition,we observe that the CIR is closely related with the integrated properties of the stellar population in the nuclear rings,associating the rings hosting older and less massive star clusters with low values of CIR.Thus,the CIR can serve as a crucial parameter in unfolding the coupled evolution of bars and rings as it is intimately connected with both their properties.展开更多
We use 1221 galaxies with unusually high gas-phase metallicity to study their physical properties.The scope of redshift is 0.02 < z < 0.25 for these galaxies with unusually high gas-phase metallicity.Our goal is...We use 1221 galaxies with unusually high gas-phase metallicity to study their physical properties.The scope of redshift is 0.02 < z < 0.25 for these galaxies with unusually high gas-phase metallicity.Our goal is to understand the physical origins of the high gas-phase metallicity.To address this study,we select a control sample matching similar redshift and stellar mass.Our main results are as follows.(i) Compared with the control sample,the high-metallicity sample shows lower ionization parameter,higher electron density and more dust content.(ii) We also find that the high-metallicity sample has older stellar age and higher [Mgb/] ratio,which indicates that the high-metallicity sample has shorter timescale of star formation.(iii) According to the plane of Hδ_A vs.D_n4000,we can see that the control sample has higher HδAand lower D_n4000 than the high-metallicity sample,which may imply that the control sample experiences recent star formation.(iv) There is a significant difference in gas distribution between the highmetallicity and control samples.The high-metallicity sample has lower gas fraction than control sample,which indicates that galaxies have high gas-phase metallicity probably due to their low HI gas fraction.(v) There is no significant difference between the high-metallicity and control samples in environment,which may suggest that the environment has no effect on gas-phase metallicity.展开更多
We investigate the color gradients of galaxies at 0.5 < z < 1.0, using a sample of ~35 000 galaxies with both spectroscopy from the final data release of the VIMOS Public Extragalactic Redshift Survey(VIPERS), a...We investigate the color gradients of galaxies at 0.5 < z < 1.0, using a sample of ~35 000 galaxies with both spectroscopy from the final data release of the VIMOS Public Extragalactic Redshift Survey(VIPERS), and photometry in ultraviolet/optical/near-infrared bands from the VIPERS-MultiLambda Survey(VIPERS-MLS) and the Canada-France-Hawaii Telescope Legacy Survey(CFHTLS).We estimate rest-frame colors, stellar mass, star formation rate from fitting the Spectral Energy Distribution(SED) for each galaxy, as well as a two-zone color ?(u-r), defined as the difference in rest-frame(u-r) color between the outer and inner region of the galaxy. We find that the two-zone color shows weak or no correlations with all galaxy properties considered except stellar mass. On average, ?(u-r) decreases with increasing stellar mass, indicating relatively red colors in galactic centers of more massive galaxies. We then compare the properties of "red-cored" and "blue-cored" galaxies,defined to have either a negative or a positive ?(u-r) respectively. Although the two types of galaxies show similar distributions in most properties, we find massive red-cored galaxies with M*> 1010.5M⊙to have larger sizes at given stellar mass(thus lower surface mass densities), and less massive red-cored galaxies with M*< 1010.5M⊙to have lower central galaxy fraction. These findings can be understood if one assumes that the star formation process happens from inside out, in the same way as recently emphasized in studies of low-z galaxies. The similarity between the galaxies at intermediate redshifts and those at low redshifts supports the idea that galaxy evolution since z~1 has been mainly driven by secular processes internal to galaxies rather than galaxy mergers or external environment.展开更多
We investigate the dependence of clustering on luminosity, stellar mass and color gradient for galaxies at 0.5 < z < 1, using a sample of;300 galaxies from the final data release of the VIMOS Public Extragalacti...We investigate the dependence of clustering on luminosity, stellar mass and color gradient for galaxies at 0.5 < z < 1, using a sample of;300 galaxies from the final data release of the VIMOS Public Extragalactic Redshift Survey（VIPERS-PDR2）. We estimate both the auto-correlation function for galaxy samples selected by B-band absolute magnitude and stellar mass, and the cross-correlation function of galaxy samples selected by color gradient with respect to the full galaxy sample. The autocorrelation function amplitudes at fixed scale are found to positively correlate with both galaxy luminosity and stellar mass, and the effect holds for all the scales probed(0.2 h;Mpc < rp< 20 h;Mpc),in good agreement with previous measurements based on an earlier data release of VIPERS. When the stellar mass is limited to a narrow range, we find the clustering power to be essentially independent of galaxy color gradient, and this conclusion is true for all the masses and all the scales considered here. In a parallel paper, we find that the half-light radius is the only galaxy property other than stellar mass that is related to color gradient. Considering the previous finding that clustering depends weakly on galaxy structure at given mass, the non-dependence of clustering on color gradient found here reinforces our conclusion that the color gradient and structural parameters of a galaxy are intrinsically related to each other.展开更多
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...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 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 < 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.展开更多
GW170817 is the unique gravitational-wave(GW)event associated with the electromagnetic(EM)counterpart GRB 170817A.NGC 4993 is identified as the host galaxy of GW170817/GRB 170817A.In this paper,we focus on the spatial...GW170817 is the unique gravitational-wave(GW)event associated with the electromagnetic(EM)counterpart GRB 170817A.NGC 4993 is identified as the host galaxy of GW170817/GRB 170817A.In this paper,we focus on the spatially resolved properties of NGC 4993.We present the photometric results from the comprehensive data analysis of the high spatial-resolution images in the different optical bands.The morphological analysis reveals that NGC 4993 is a typical early-type galaxy without significant remnants of a major galaxy merger.The spatially resolved stellar population properties of NGC 4993 suggest that the galaxy center has passive evolution with the outskirt formed by gas accretion.We derive the merging rate of the compact object per galaxy by a co-evolution scenario of a supermassive black hole and its host galaxy.If the galaxy formation is at redshift 1.0,the merging rate per galaxy is from 3.2×10^(-4)to 7.7×10^(-5)within the merging decay time from 1.0 to 5.0 Gyr.The results provide vital information for ongoing GW EM counterpart detections.The Hubble space telescope data analysis presented in this paper can be also applied to Chinese Space Station Telescope research in the future.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,grant No.11063004)。
文摘We analyzed the relationship between several basic parameters describing supermassive black holes such as jet power,black hole spin,accretion disk magnetic field,black hole mass,etc.We found that there is a general correlation between these parameters,such as jet power is significantly positively correlated with black hole spin,while black hole mass is significantly negatively correlated with black hole spin.To apprehend these relationships,we consider the Blandford–Znajek model to be superior to the Blandford–Payne model.It is also found that the intrinsic gamma luminosity of the FSRQs has a positive correlation with the accretion disk magnetic field,while the intrinsic gamma luminosity of the BL Lacs has a negative correlation with the accretion disk magnetic field.A feedback effect may exist between accretion disk accretion rate and magnetic field,which may be the key to the evolution between BL Lacs and FSRQs.There is no significant difference in the jet power and jet generation efficiency of FSRQs and BL Lacs,which suggests that the jets are generated by the same mechanism.The contribution rate of accretion rate to jet generation efficiency is high,while the contribution rate of accretion rate to jet power is very low.
文摘This paper is a further elaboration of the author’s Time Dilation Cosmology (TDC) holographic model that ties gravitation and celestial mechanics and kinematics directly to time dilation, resolving all the major conundrums in astrophysics, and ties astrophysics directly to quantum physics. It begins with a brief summary of the TDC model and contains the new derivation for the time dilation version of the formula for summing relativistic velocities, Einstein’s gravitational constant and the time dilation versions for the Lorentz factor and the Euclidean norm of the 3d velocity vector, the two of which can then be used in the Four-velocity formula. It is demonstrated how orbital curvature is manifested as the resultant of two time dilation-manifested velocities. It also explains why an interferometer cannot distinguish free fall from zero gravity and further elaborates on the author’s previous explanations of how spiral galaxies are formed, and contains mathematical proof that Black Holes are actually Magnetospheric Eternally Collapsing Objects (MECOs) that are massless spacetime vortices.
基金supported by the National SKA Program of China(Nos.2022SKA0110201 and 2022SKA0110200)CAS Project for Young Scientists in Basic Research grant No.YSBR-062+11 种基金the National Natural Science Foundation of China(NSFC)(grant Nos.12033008,11622325,11988101)the K.C.Wong Education Foundationthe science research grants from the China Manned Space Project(CMSP)with NO.CMS-CSST-2021-A03 and NO.CMS-CSST-2021-A07support of the Tsinghua Shui Mu ScholarshipNSFC(grant No.12073014)the science research grants from the China Manned Space Project with No.CMS-CSST2021-A05Tsinghua University Initiative Scientific Research Program(No.20223080023)supported by NSFC(grant Nos.11988101,12041302,and U1931110)supported by the science research grant from the China Manned Space Project with grant No.CMS-CSST-2021-A08support from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sk?odowska-Curie grant agreement No.101086388supported by the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CASsupported by the Key Research Project of Zhejiang Lab(No.2021PE0AC03)。
文摘Environments play an important role in galaxy formation and evolution,particularly in regulating the content of neutral gas.However,current HI surveys have limitations in their depth,which prevents them from adequately studying low HI content galaxies in high-density regions.In this study,we address this issue by employing the Five-hundred-meter Aperture Spherical radio Telescope with extensive integration times to complement the relatively shallow Arecibo Legacy Fast Arecibo L-band Feed Array HI survey.This approach allows us to explore the gas content of dwarf galaxies across various environments.We observe a positive relationship between HI mass and stellar mass in dwarf galaxies,with a well-defined upper boundary for HI mass that holds true in both observations and simulations.Furthermore,we find a decrease in the H I-to-stellar mass ratio(M_(HI)/M_*)as the density of the environment increases,irrespective of whether it is determined by the proximity to the nearest group or the projected number density.Comparing our observations to simulations,we note a steeper slope in the relationship,indicating a gradual gas-stripping process in the observational data.Additionally,we find that the scaling relation between the M_(HI)/M_*and optical properties can be improved by incorporating galaxy environments.
基金supported by the National Natural Science Foundation of China(grants 12133008,12192220,and 12192223)。
文摘We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium,active galactic nuclei(AGN)feedback and black hole(BH)feeding in a massive compact galaxy,with an emphasis on the impact of different central BH masses.We find that with a more massive central BH,high-speed outflows are more prominent,and the gas fraction in the compact galaxy is reduced.Due to the lower gas density and higher gas temperature,the compact galaxy with a more massive BH(MAS galaxy)remains predominantly single-phase with the cooling time t_(cool)■100t_(ff).In contrast,the compact galaxy with the reference BH mass(REF galaxy)maintains a higher gas fraction with a shorter cooling time,slightly more multiphase gas and less prominent outflows.We further demonstrate that the difference in gas thermal states and kinematics is caused by the stronger AGN feedback in the compact galaxy with a more massive BH,where the AGN wind power is twice as much as that with the reference BH.Since the AGN feedback efficiently suppresses the inflow rate and the BH feeding rate,the BH mass growth is significant in neither the compact galaxy with the reference BH nor that with the more massive BH,only by 24%and 11%of the initial BH mass,respectively,over the entire evolution time of 10 Gyr.We thus posit that without ex situ mass supply from mergers,the massive BHs in compact galaxies cannot grow significantly via gas accretion during the late phase,but might have already formed by the end of the rapid early phase of galaxy formation.
文摘This model ties gravitation and celestial mechanics and kinematics directly to time dilation. It is a new theory of cosmology and the evolution of galaxies. Space and time are not two separate things, but two aspects of a single thing, “spacetime”. Whatever affects space, affects time, and vice-versa. If time speeds up, space must contract to maintain the speed of light, c, and when space thickens into a mass, it is harder to evolve forward, and time appears to slow. If spatial events are spinning as time passes, then the forward direction of time is spinning. This is Einstein’s curvature in the forward direction of time. Herein, the basis is outlined for time dilation cosmology in a spacetime/quantum continuum, including the time dilation-based derivation of the mass of the Cosmic Microwave Background Radiation (CMBR), and time dilation formulas are derived for stellar system orbital, and galactic rotation, velocities, the force in time in Newtons, the Hamiltonian, the Hubble shift, the empirical gravitational constant, G, and other formulas, showing their direct relationship to the difference in the rate of time between the far distant observer’s invariant 1 s/s rate of time and the slower rate of time at the coordinate point, proving the universe is not composed of separate bodies moving through space, but is an evolving 3-dimensional holographic continuum containing varying densities evolving forward in the forward direction of time, the 4th dimension, at apparently different rates of time, the velocities merely being compensation for those slower rates of time in a continuum evolving forward overall at c, which is why light propagates at c, even from a moving source. As per General Relativity, if there is no rate of time difference between coordinate points, there is no gravitational attraction between those points, and no gravitationally induced velocity. This model resolves all the major conundrums in astrophysics, eliminating Dark Energy and Dark Matter, and ties astrophysics directly to quantum p
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financial support from the SERB,DST,Government of India through the project CRG/2019/001110support from IUCAA,Pune through the associateship programDST,Government of India for support through a National Post Doctoral Fellowship(N-PDF)。
文摘We study the color and star formation rates of paired galaxies in filaments and sheets using the EAGLE simulations.We find that the major pairs with pair separation<50 kpc are bluer and more star-forming in filamentary environments compared to those hosted in sheet-like environments.This trend reverses beyond a pair separation of~50 kpc.The interacting pairs with larger separations(>50 kpc)in filaments are on average redder and low-star-forming compared to those embedded in sheets.The galaxies in filaments and sheets may have different stellar mass and cold gas mass distributions.Using a KS test,we find that for paired galaxies with pair separation<50 kpc,there are no significant differences in these properties in sheets and filaments.The filaments transport gas toward the cluster of galaxies.Some earlier studies find preferential alignment of galaxy pairs with the filament axis.Such alignment of galaxy pairs may lead to different gas accretion efficiency in galaxies residing in filaments and sheets.We propose that the enhancement of star formation rate at smaller pair separation in filaments is caused by the alignment of galaxy pairs.A recent study with SDSS data reports the same findings.The confirmation of these results by the EAGLE simulations suggests that the hydrodynamical simulations are powerful theoretical tools for studying galaxy formation and evolution in the cosmic web.
基金Supported by the National Natural Science Foundation of China(Grant Nos. 10878001, 10973010 and 11125313)the National Basic Research Program of China (973 Program+2 种基金 Grant Nos. 2009CB824900 and 2009CB824904)the Shanghai Science and Technology Commission (Program of Shanghai Subject Chief Scientist Grant Nos. 12XD1406200 and 11DZ2260700)
文摘We present a study of a fossil cluster,SDSS J0150–1005（z 0.364）,with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent merger.According to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±11.The central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar temperatures.Our results indicate that SDSS J0150–1005 formed during an early epoch.
基金Supported by the National Natural Science Foundation of China
文摘In this second paper of our series, we estimate the age of 41 star clusters, which were detected by Melnick & D'odorico in the nearby spiral galaxy M33, by comparing the integrated photometric measurements with theoretical stellar population synthesis models of Bruzual & Charlot. Also, we calculate the mass of these star clusters using the theoretical M/LV ratio. The results show that, these star clusters formed continuously in M33 from ~ 7 × 10<SUP>6</SUP>–10<SUP>10</SUP> years and have masses between ~ 10<SUP>3</SUP> and 2 × 10<SUP>6</SUP>M<SUB>☉</SUB>. M33 frames were observed as a part of the BATC Multicolor Survey of the sky in 13 intermediate-band filters from 3800 to 10 000?. The relation between age and mass confirms that the sample star cluster masses systematically decrease from the oldest to the youngest.
基金Supported by the National Natural Science Foundation of China
文摘Based on the large field multicolor observations ofBeijing-Arizona-Taiwan-Connecticut (BATC) program, we obtain the spectral energy distribution (SED)for individual regions of M81. We study the structure and evolution of M81 with an evolutionarypopulation synthesis (EPS) model, PEGASE. We find that the exponentially deceasing star formationrate (SFR) with star formation scale 3 Gyr (hereafter Exp, τ = 3 Gyr) gives the best agreementbetween the model predictions and the observed SEDs. We then obtain the structure, age distributionand evolutionary history of M81. There is a clear age gradient between the central and outerregions. The populations in the central regions are older than 7 Gyr, those in the outer regions areyounger, at about 4.5 Gyr. The youngest components in the spiral arms have ages of about 2.5 Gyr orless.
基金supported by the National Basic Research Program of China (Grant No. 2009CB824800)
文摘There are significant correlations between the broad line region luminosity LBLR,the quantity Δmax(maximum of Δ≡log[(Fν)cm/(Fν)mm]) and redshift z.There are strong correlations between the extended radio luminosity PE,LBLR and Δmax.Our results indicate that FSRQs with higher mass accretion rate M and black hole spin j occur in the earlier,highly luminous,violent phase of the galactic sequence,and BL Lacs with lower M and j occur in the lower luminous,later phase of the galactic sequence,while FR II BL Lacs are possible intermediate stages in the sequence of blazars from FSRQs to FR I BL Lacs with j lower than FR II BL Lacs.It is indicated that there is a disk-jet symbiosis in blazars.
基金the financial support from Kerala State Council for Science,Technology and Environment(KSCSTE)
文摘Using a sample of 13 early-type spiral galaxies hosting nuclear rings,we report remarkable correlations between the properties of the nuclear rings and the central intensity ratio(CIR) of their host galaxies.The CIR,a function of intensity of light within the central 1.5 and 3 arcsec region,is found to be a vital parameter in galaxy evolution,as it shares strong correlations with many structural and dynamical properties of early-type galaxies,including mass of the central supermassive black hole(SMBH).We use archival HST images for aperture photometry at the centre of the galaxy image to compute the CIR.We observe that the relative sizes of nuclear rings and ring cluster surface densities strongly correlate with the CIR.These correlations suggest reduced star formation in the centres of galaxies hosting small and dense nuclear rings.This scenario appears to be a consequence of strong bars as advocated by the significant connection observed between the CIR and bar strengths.In addition,we observe that the CIR is closely related with the integrated properties of the stellar population in the nuclear rings,associating the rings hosting older and less massive star clusters with low values of CIR.Thus,the CIR can serve as a crucial parameter in unfolding the coupled evolution of bars and rings as it is intimately connected with both their properties.
基金supported by the National Key Research and Development Program of China(No.2017YFA0402703)the National Natural Science Foundation of China(Grant Nos.11733002and 11773013)
文摘We use 1221 galaxies with unusually high gas-phase metallicity to study their physical properties.The scope of redshift is 0.02 < z < 0.25 for these galaxies with unusually high gas-phase metallicity.Our goal is to understand the physical origins of the high gas-phase metallicity.To address this study,we select a control sample matching similar redshift and stellar mass.Our main results are as follows.(i) Compared with the control sample,the high-metallicity sample shows lower ionization parameter,higher electron density and more dust content.(ii) We also find that the high-metallicity sample has older stellar age and higher [Mgb/] ratio,which indicates that the high-metallicity sample has shorter timescale of star formation.(iii) According to the plane of Hδ_A vs.D_n4000,we can see that the control sample has higher HδAand lower D_n4000 than the high-metallicity sample,which may imply that the control sample experiences recent star formation.(iv) There is a significant difference in gas distribution between the highmetallicity and control samples.The high-metallicity sample has lower gas fraction than control sample,which indicates that galaxies have high gas-phase metallicity probably due to their low HI gas fraction.(v) There is no significant difference between the high-metallicity and control samples in environment,which may suggest that the environment has no effect on gas-phase metallicity.
基金supported by the National Key Basic Research Program of China(No.2015CB857004)the National Natural Science Foundation of China(Grant Nos.11173045,11233005,11325314 and 11320101002)
文摘We investigate the color gradients of galaxies at 0.5 < z < 1.0, using a sample of ~35 000 galaxies with both spectroscopy from the final data release of the VIMOS Public Extragalactic Redshift Survey(VIPERS), and photometry in ultraviolet/optical/near-infrared bands from the VIPERS-MultiLambda Survey(VIPERS-MLS) and the Canada-France-Hawaii Telescope Legacy Survey(CFHTLS).We estimate rest-frame colors, stellar mass, star formation rate from fitting the Spectral Energy Distribution(SED) for each galaxy, as well as a two-zone color ?(u-r), defined as the difference in rest-frame(u-r) color between the outer and inner region of the galaxy. We find that the two-zone color shows weak or no correlations with all galaxy properties considered except stellar mass. On average, ?(u-r) decreases with increasing stellar mass, indicating relatively red colors in galactic centers of more massive galaxies. We then compare the properties of "red-cored" and "blue-cored" galaxies,defined to have either a negative or a positive ?(u-r) respectively. Although the two types of galaxies show similar distributions in most properties, we find massive red-cored galaxies with M*> 1010.5M⊙to have larger sizes at given stellar mass(thus lower surface mass densities), and less massive red-cored galaxies with M*< 1010.5M⊙to have lower central galaxy fraction. These findings can be understood if one assumes that the star formation process happens from inside out, in the same way as recently emphasized in studies of low-z galaxies. The similarity between the galaxies at intermediate redshifts and those at low redshifts supports the idea that galaxy evolution since z~1 has been mainly driven by secular processes internal to galaxies rather than galaxy mergers or external environment.
基金supported by the National Key Basic Research Program of China(No.2015CB857004)the National Key Basic Research and Development Program of China(No.2018YFA0404502)NSFC(Grant Nos.11173045,11233005,11325314 and 11320101002)
文摘We investigate the dependence of clustering on luminosity, stellar mass and color gradient for galaxies at 0.5 < z < 1, using a sample of;300 galaxies from the final data release of the VIMOS Public Extragalactic Redshift Survey（VIPERS-PDR2）. We estimate both the auto-correlation function for galaxy samples selected by B-band absolute magnitude and stellar mass, and the cross-correlation function of galaxy samples selected by color gradient with respect to the full galaxy sample. The autocorrelation function amplitudes at fixed scale are found to positively correlate with both galaxy luminosity and stellar mass, and the effect holds for all the scales probed(0.2 h;Mpc < rp< 20 h;Mpc),in good agreement with previous measurements based on an earlier data release of VIPERS. When the stellar mass is limited to a narrow range, we find the clustering power to be essentially independent of galaxy color gradient, and this conclusion is true for all the masses and all the scales considered here. In a parallel paper, we find that the half-light radius is the only galaxy property other than stellar mass that is related to color gradient. Considering the previous finding that clustering depends weakly on galaxy structure at given mass, the non-dependence of clustering on color gradient found here reinforces our conclusion that the color gradient and structural parameters of a galaxy are intrinsically related to each other.
基金the 3D-HST Treasury Program (GO 12177 and 12328) with the NASA/ESA HSTsupported by the National Natural Science Foundation of China (Nos. 11673004, 11873032 and 11433005)by the Research Fund for the Doctoral Program of Higher Education of China (No. 20133207110006)he support from Yunnan young and middleaged academic and technical leaders reserve talent program (No. 201905C160039)
文摘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 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 < 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.
基金supported by the National Science Foundation of China(NSFC 11673062)the China Manned Space Project(CMS-CSST-2021-A06)+7 种基金the Yunnan Revitalization Talent Support Program(Yun Ling Scholar Award)support from the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB473)support from the NSFC(11773076 and 12073078)the National Key R&D Program of China(2017YFA0402703)science research grants from the China Manned Space Project(Nos.CMS-CSST-2021-A02,CMS-CSST-2021-A04 and CMS-CSST-2021-A07)support from the NSFC(11733006 and 12273052)support from the NSFC(12173079)support from the NSFC(U1831135)。
文摘GW170817 is the unique gravitational-wave(GW)event associated with the electromagnetic(EM)counterpart GRB 170817A.NGC 4993 is identified as the host galaxy of GW170817/GRB 170817A.In this paper,we focus on the spatially resolved properties of NGC 4993.We present the photometric results from the comprehensive data analysis of the high spatial-resolution images in the different optical bands.The morphological analysis reveals that NGC 4993 is a typical early-type galaxy without significant remnants of a major galaxy merger.The spatially resolved stellar population properties of NGC 4993 suggest that the galaxy center has passive evolution with the outskirt formed by gas accretion.We derive the merging rate of the compact object per galaxy by a co-evolution scenario of a supermassive black hole and its host galaxy.If the galaxy formation is at redshift 1.0,the merging rate per galaxy is from 3.2×10^(-4)to 7.7×10^(-5)within the merging decay time from 1.0 to 5.0 Gyr.The results provide vital information for ongoing GW EM counterpart detections.The Hubble space telescope data analysis presented in this paper can be also applied to Chinese Space Station Telescope research in the future.
