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General Relativity and the Tully-Fisher Relation for Rotating Galaxies
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作者 Yogendra Srivastava Giorgio Immirzi +2 位作者 John Swain Orlando Panella Simone Pacetti 《Journal of Modern Physics》 CAS 2022年第11期1452-1473,共22页
The flat limit of rotational velocity (v<sub>&phi;</sub>) approximately equal to the “edge”-velocity of a galaxy is related to the baryonic mass (M<sub>B</sub>) via the T-F relationship w... The flat limit of rotational velocity (v<sub>&phi;</sub>) approximately equal to the “edge”-velocity of a galaxy is related to the baryonic mass (M<sub>B</sub>) via the T-F relationship with n ≈ 4. We explore the connection between mass and the limiting velocity in the framework of general relativity (GR) using the Weyl metric for axially-symmetric galaxies that are supported entirely by their rotational motion. While for small distances from the center, the Newtonian description is accurate as one moves beyond the (baryonic) edge of the galaxy, Lenz’s law and non-linearity of the gravitational field inherent in GR not only lead to a flat velocity (obviating its Keplerian fall), but also provide its tight log-log relationship with the enclosed (baryonic) mass. 展开更多
关键词 GR Weyl Metric Rotating galaxies Flat Rotation Curves TF Relation
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Tracing the Evolution of Galactic Bars in Field Galaxies:A Local-to-high-redshift Perspective
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作者 M.A.Chacón R.Delgado-Serrano +1 位作者 B.Cervantes Sodi Y.Jaffé 《Research in Astronomy and Astrophysics》 2025年第11期155-165,共11页
Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand... Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand the evolution of these structural components through cosmic time.To this end,two complementary bar detection techniques were employed:elliptical isophote fitting and two-dimensional Fourier analysis,both applied to deep optical images.The observational samples were drawn from previously established and calibrated catalogs to ensure a homogeneous selection in stellar mass,enabling a robust comparison between local galaxies(z~0.027)and those in the distant Universe(z~0.7).This study systematically applies both isophotal fitting and Fourier decomposition across a wide redshift range,offering a comprehensive view of the evolution of bar incidence as a function of stellar mass and morphology.The results indicate that the fraction of barred galaxies is significantly higher in the local Universe than at earlier epochs,particularly among spiral galaxies.Furthermore,a clear correlation is observed between the presence of bars and stellar mass,especially in the high-mass regime(log(M_*/M☉)>10.5).In distant galaxies,this fraction is lower across all mass ranges,which may be related to more active dynamical processes.Overall,the findings reinforce the idea that stellar bars emerge as a consequence of dynamical cooling and the progressive stabilization of galactic disks,playing a key role in gas transport and the internal structural evolution of galaxies from z~1 to the present day. 展开更多
关键词 Galaxy:kinematics and dynamics galaxies:general galaxies:evolution galaxies:distances and redshifts galaxies:luminosity function mass function Galaxy:disk
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Detection of Emission Line Galaxies in the Slitless Spectra of HST and CSST
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作者 Kaiyuan Chen Shuairu Zhu +1 位作者 Linhua Jiang Zhenya Zheng 《Research in Astronomy and Astrophysics》 2025年第2期150-159,共10页
Slitless spectroscopy onboard space telescopes is a powerful tool to detect emission-line objects such as emissionline galaxies(ELGs)and quasars.In this work,we present a study of ELGs observed with slitless spectrosc... Slitless spectroscopy onboard space telescopes is a powerful tool to detect emission-line objects such as emissionline galaxies(ELGs)and quasars.In this work,we present a study of ELGs observed with slitless spectroscopy by the Hubble Space Telescope(HST)in a deep field of~44 arcmin^(2).This is one of the deepest HST fields with a wealth of imaging and spectral data.In particular,previous VLT/MUSE observations have covered this field and identified a large number of ELGs.We reduce the HST spectra using the latest pipeline with a forward modeling algorithm and construct a sample of ELGs.By comparing with the MUSE spectra,we characterize our ELG detection in the HST spectra,including the impact of the line flux,line width,signal-to-noise ratio,etc.We find that the morphological broadening may affect the detection of ELGs,such that more compact sources are easier to be detected in slitless spectra.We discuss its implications to future slitless spectroscopic surveys that will be carried out by the China Space Station Telescope(CSST)and find that the CSST slitless spectroscopy has a capability comparable to that of HST in terms of the detection of emission lines. 展开更多
关键词 techniques:spectroscopic surveys methods:data analysis galaxies:general galaxies:ISM
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A Generative Model-based Emulator for Mocking Galaxies with Spiral Arms
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作者 Zhenyang Xu Liangping Tu +3 位作者 Jiawei Miao Mingyu Zheng Yu Mao Yue Jiang 《Research in Astronomy and Astrophysics》 2025年第12期283-301,共19页
In the study of spiral galaxy morphology,spiral arm structures are valuable for intuitively reflecting active physical and chemical processes within galaxies.However,long-term scarcity of high-quality one-,three-,and ... In the study of spiral galaxy morphology,spiral arm structures are valuable for intuitively reflecting active physical and chemical processes within galaxies.However,long-term scarcity of high-quality one-,three-,and four-armed galaxy samples has limited deep learning model performance.To address this,this study developed a spiral galaxy data simulation program with a three-stage workflow:first,screening highly reliable training samples;second,selecting the best-performing Imagen architecture as the generative model after comparing nine mainstream ones;finally,training Imagen to generate an open data set of 9402 one-/three-armed galaxies,expanding the original sample size by 6 times.Multi-dimensional evaluations verified reliability and usability:Fréchet Inception Distance scores for N=1 and N=3 tasks were 6.05 and 9.13;the t-distributed Stochastic Neighbor Embedding showed generated data covered and expanded real data distribution;the Structural Similarity Index Measure confirmed no sample duplication.In downstream validation,data augmentation improved seven classification models'average accuracy by 8.7%(DenseNet peaked at 97%),and SHapley Additive exPlanations analysis showed model decisions focused on spiral arm topology.In conclusion,the program and data set support spiral galaxy morphology deep learning research and are publicly available at https://github.com/TuAstroAILab/AstroGS. 展开更多
关键词 methods:data analysis astronomical databases:miscellaneous techniques:image processing galaxies:clusters:general
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Analgesic effect and safety of dexmedetomidine-assisted intravenous-inhalation combined general anesthesia in laparoscopic minimally invasive inguinal hernia surgery 被引量:1
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作者 Qian-Xing Lou Ke-Ping Xu 《World Journal of Gastrointestinal Surgery》 2025年第3期161-170,共10页
BACKGROUND Currently,very few studies have examined the analgesic effectiveness and safety of dexmedetomidine-assisted intravenous-inhalation combined general anesthesia in laparoscopic minimally invasive surgery for ... BACKGROUND Currently,very few studies have examined the analgesic effectiveness and safety of dexmedetomidine-assisted intravenous-inhalation combined general anesthesia in laparoscopic minimally invasive surgery for inguinal hernia.AIM To investigate the analgesic effect and safety of dexmedetomidine-assisted intravenous-inhalation combined general anesthesia in laparoscopic minimally invasive surgery for inguinal hernia.METHODS In this retrospective study,94 patients scheduled for laparoscopic minimally invasive surgery for inguinal hernia,admitted to Yiwu Central Hospital between May 2022 and May 2023,were divided into a control group(inhalation combined general anesthesia)and a treatment group(dexmedetomidine-assisted intrave-nous-inhalation combined general anesthesia).Perioperative indicators,analgesic effect,preoperative and postoperative 24-hours blood pressure(BP)and heart rate(HR),stress indicators,immune function levels,and adverse reactions were com-pared between the two groups.RESULTS Baseline data,including age,hernia location,place of residence,weight,monthly income,education level,and underlying diseases,were not significantly different between the two groups,indicating comparability(P>0.05).No significant difference was found in operation time and anesthesia time between the two groups(P>0.05).However,the treatment group exhibited a shorter postoperative urinary catheter removal time and hospital stay than the control group(P<0.05).Preoperatively,no significant differences were found in the visual analog scale(VAS)scores between the two groups(P>0.05).However,at 12,18,and 24 hours postoper-atively,the treatment group had significantly lower VAS scores than the control group(P<0.05).Although no significant differences in preoperative hemodynamic indicators were found between the two groups(P>0.05),both groups experienced some extent of changes in postoperative HR,diastolic BP(DBP),and systolic BP(SBP).Nevertheless,the treatment group showed smaller changes in HR,DBP,and SBP than the control group(P<0.05).Preoperative immune function indicators showed no significant differences between the two groups(P>0.05).However,postoperatively,the treatment group demonstrated higher levels of CD3+,CD4+,and CD4+/CD8+and lower levels of CD8+than the control group(P<0.05).The rates of adverse reactions were 6.38%and 23.40%in the treatment and control groups,respectively,revealing a significant difference(χ2=5.371,P=0.020).CONCLUSION Dexmedetomidine-assisted intravenous-inhalation combined general anesthesia can promote early recovery of patients undergoing laparoscopic minimally invasive surgery for inguinal hernia.It ensures stable blood flow,improves postoperative analgesic effects,reduces postoperative pain intensity,alleviates stress response,improves immune function,facilitates anesthesia recovery,and enhances safety. 展开更多
关键词 DEXMEDETOMIDINE Intravenous-inhalation combined general anesthesia Inguinal hernia Laparoscopic minimally invasive surgery Analgesia SAFETY
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Optimizing CNN Architectures for Face Liveness Detection:Performance,Efficiency,and Generalization across Datasets 被引量:1
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作者 Smita Khairnar Shilpa Gite +2 位作者 Biswajeet Pradhan Sudeep D.Thepade Abdullah Alamri 《Computer Modeling in Engineering & Sciences》 2025年第6期3677-3707,共31页
Face liveness detection is essential for securing biometric authentication systems against spoofing attacks,including printed photos,replay videos,and 3D masks.This study systematically evaluates pre-trained CNN model... Face liveness detection is essential for securing biometric authentication systems against spoofing attacks,including printed photos,replay videos,and 3D masks.This study systematically evaluates pre-trained CNN models—DenseNet201,VGG16,InceptionV3,ResNet50,VGG19,MobileNetV2,Xception,and InceptionResNetV2—leveraging transfer learning and fine-tuning to enhance liveness detection performance.The models were trained and tested on NUAA and Replay-Attack datasets,with cross-dataset generalization validated on SiW-MV2 to assess real-world adaptability.Performance was evaluated using accuracy,precision,recall,FAR,FRR,HTER,and specialized spoof detection metrics(APCER,NPCER,ACER).Fine-tuning significantly improved detection accuracy,with DenseNet201 achieving the highest performance(98.5%on NUAA,97.71%on Replay-Attack),while MobileNetV2 proved the most efficient model for real-time applications(latency:15 ms,memory usage:45 MB,energy consumption:30 mJ).A statistical significance analysis(paired t-tests,confidence intervals)validated these improvements.Cross-dataset experiments identified DenseNet201 and MobileNetV2 as the most generalizable architectures,with DenseNet201 achieving 86.4%accuracy on Replay-Attack when trained on NUAA,demonstrating robust feature extraction and adaptability.In contrast,ResNet50 showed lower generalization capabilities,struggling with dataset variability and complex spoofing attacks.These findings suggest that MobileNetV2 is well-suited for low-power applications,while DenseNet201 is ideal for high-security environments requiring superior accuracy.This research provides a framework for improving real-time face liveness detection,enhancing biometric security,and guiding future advancements in AI-driven anti-spoofing techniques. 展开更多
关键词 Face liveness detection cross-dataset generalization real-time face authentication transfer learning DenseNet201 VGG16 InceptionV3 deep learning
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Dual encoding feature filtering generalized attention UNET for retinal vessel segmentation
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作者 ISLAM Md Tauhidul WU Da-Wen +6 位作者 TANG Qing-Qing ZHAO Kai-Yang YIN Teng LI Yan-Fei SHANG Wen-Yi LIU Jing-Yu ZHANG Hai-Xian 《四川大学学报(自然科学版)》 北大核心 2025年第1期79-95,共17页
Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited t... Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited training data,imbalance data distribution,and inadequate feature extraction persist,hindering both the segmentation performance and optimal model generalization.Addressing these critical issues,the DEFFA-Unet is proposed featuring an additional encoder to process domain-invariant pre-processed inputs,thereby improving both richer feature encoding and enhanced model generalization.A feature filtering fusion module is developed to ensure the precise feature filtering and robust hybrid feature fusion.In response to the task-specific need for higher precision where false positives are very costly,traditional skip connections are replaced with the attention-guided feature reconstructing fusion module.Additionally,innovative data augmentation and balancing methods are proposed to counter data scarcity and distribution imbalance,further boosting the robustness and generalization of the model.With a comprehensive suite of evaluation metrics,extensive validations on four benchmark datasets(DRIVE,CHASEDB1,STARE,and HRF)and an SLO dataset(IOSTAR),demonstrate the proposed method’s superiority over both baseline and state-of-the-art models.Particularly the proposed method significantly outperforms the compared methods in cross-validation model generalization. 展开更多
关键词 Vessel segmentation Data balancing Data augmentation Dual encoder Attention Mechanism Model generalization
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Strong Correlation Between Galactic HI-to-stellar Mass Ratio and Halo Spin Explored by HI-rich Galaxies
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作者 Shihong Liu Yu Rong +1 位作者 Zichen Hua Huijie Hu 《Research in Astronomy and Astrophysics》 2025年第8期1-5,共5页
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
关键词 galaxies:statistics galaxies:evolution galaxies:formation galaxies:halos
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Halo Spin Dependence on Environment for H I-bearing Galaxies
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作者 Zichen Hua Yu Rong Huijie Hu 《Research in Astronomy and Astrophysics》 2025年第4期1-5,共5页
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
关键词 galaxies:halos galaxies:evolution galaxies:statistics
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Small-scale Clustering of Star-forming Galaxies Relative to Early-type and Late-type Galaxies:IllustrisTNG versus the Sloan Digital Sky Survey
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作者 Yan Fang Longlong Feng +2 位作者 Cheng Li Weishan Zhu Yanhan Guo 《Research in Astronomy and Astrophysics》 2025年第8期68-80,共13页
We investigate the small-scale clustering of star-forming galaxies(SFGs) in the local universe, using both observational samples from the final data release of the Sloan Digital Sky Survey and IllustrisTNG300, one of ... We investigate the small-scale clustering of star-forming galaxies(SFGs) in the local universe, using both observational samples from the final data release of the Sloan Digital Sky Survey and IllustrisTNG300, one of the state-of-the-art hydrodynamic simulations of galaxy formation. We measure the projected two-point crosscorrelation function, wp(rp), for subsamples of SFGs with different specific star formation rates(sSFRs) and stellar masses(M*), with respect to reference samples of galaxies with early-type or late-type morphology. On scales smaller than ~100 kpc and at fixed M*, SFGs with higher sSFR are more strongly clustered, reflecting the interaction-induced central star formation found in previous studies. More importantly, the small-scale clusteringsSFR correlation is stronger when the reference sample is limited to late-type galaxies only. This confirms the previous finding that the enhancement of star formation in close pairs depends on the morphology of companion galaxies. These observational trends are broadly reproduced by IllustrisTNG300, indicating that current hydrodynamic simulations are capable of capturing the main recipes governing star formation in interacting/merging galaxies, although further work is needed to identify the exact physical processes involved. 展开更多
关键词 galaxies:evolution galaxies:star formation galaxies:interactions
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Properties of Standard,Fuzzy,and Self-interacting Dark Matter Haloes in Dwarf Galaxies
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作者 Fahmi M.Al Farisy Hesti R.T.Wulandari Azriel J.Dante 《Research in Astronomy and Astrophysics》 2025年第4期194-208,共15页
This study examines the properties of standard cold dark matter(CDM),fuzzy dark matter(FDM),and selfinteracting dark matter(SIDM)haloes by analyzing the rotation curves of selected dwarf galaxies from SPARC and LITTLE... This study examines the properties of standard cold dark matter(CDM),fuzzy dark matter(FDM),and selfinteracting dark matter(SIDM)haloes by analyzing the rotation curves of selected dwarf galaxies from SPARC and LITTLE THINGS in 3D catalogs.Utilizing the Markov Chain Monte Carlo(MCMC)method for model fitting and Bayesian Information Criterion for model comparison,we find that compared to CDM,both FDM and SIDM haloes generally provide better fits to the observed rotation curves.Our findings reveal that the concentration–mass relation derived from the dark matter-only simulations is not followed by concentrations or masses obtained from the rotation curve data.Our analysis highlights a positive correlation between the core sizes of FDM and SIDM haloes and the effective radius of the galaxy,attributable to gravitational couplings between baryonic and dark matter components.Moreover,our exploration of dark matter fractions at characteristic radii indicates considerable diversity in dark matter distributions across dwarf galaxies.Notably,FDM and SIDM exhibit greater diversity than CDM in this respect. 展开更多
关键词 galaxies:dwarf galaxies:kinematics and dynamics galaxies:haloes (cosmology:)dark matter
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Morphological Study of a Sample of Massive Quiescent Galaxies at z∼1.2
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作者 Hai Xu Y.Sophia Dai Jia-Sheng Huang 《Research in Astronomy and Astrophysics》 2025年第8期119-127,共9页
We present the morphological study of 18,572 massive quiescent galaxies at z~1.2, selected by i-y colors in the Hyper Suprime-Cam(HSC) Deep and UltraDeep fields. The majority of our sample(94.3%) fall in the quiescent... We present the morphological study of 18,572 massive quiescent galaxies at z~1.2, selected by i-y colors in the Hyper Suprime-Cam(HSC) Deep and UltraDeep fields. The majority of our sample(94.3%) fall in the quiescent region in the rest-frame UVJ diagram. Comparing the five HSC bands and the subsample with HST F160W images, consistent with the decreasing effective radius re, Sérsic index n shows an increasing trend indicating a more bulge-dominant morphology towards the infrared. Even for our massive, quiescent galaxies,which are dominated by typical elliptical galaxies with bulges, the reand n values still vary with the wavelengths.For instance, there is a systematic drop in n of ~0.4 going from y band to F160W, making 20% of the HSC “disklike” galaxies appear “bulge-like” in the HST images. We suggest to use caution when comparing galaxy morphological types based on images at different resolutions or at different wavelengths, and whenever possible,to apply a reor n correction. More massive quiescent galaxies are systematically larger than the less massive ones,though no mass dependence is found for n measurements. The size–mass relation based on our sample and lowerz control samples show a monotonic increase of rewith M*, with a power-law of 0.61 ± 0.01, lower than previously found in similar samples of smaller sizes. Future high-resolution space-based surveys like NGRST will help confirm the possible n evolution, and if the flattening at the low-mass end is a genuine physical trend or limited by the image resolutions. 展开更多
关键词 catalogs galaxies:structure galaxies:evolution
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Eleven Local Volume Dwarf Galaxies in the FASHI Survey
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作者 Aleksandra Nazarova Dmitry Makarov +2 位作者 Igor Karachentsev Chuan-Peng Zhang Ming Zhu 《Research in Astronomy and Astrophysics》 2025年第12期157-166,共10页
We determined HI parameters for eleven nearby late-type dwarf galaxies using FASHI data cubes,despite the fact that the first version of the FAS HI catalog does not list any radio sources that could correspond to thes... We determined HI parameters for eleven nearby late-type dwarf galaxies using FASHI data cubes,despite the fact that the first version of the FAS HI catalog does not list any radio sources that could correspond to these galaxies.Four of them are probable peripheral satellites of the bright spiral galaxies:NGC 3556,NGC 4258,NGC 4274 and NGC 4490,while others are isolated objects.The considered sample has the following median parameters:a heliocentric velocity of V_(h)=542 km s^(-1),an HI-line width of W_(50)=28 km s^(-1),a hydrogen mass of log(M_(HI)/M_(⊙))=6.83,a stellar mass of log(M_(*)/M_(⊙))=7.19,and a specific star formation rate of sSFR=-10.17 yr^(-1). 展开更多
关键词 galaxies:dwarf surveys galaxies:distances and redshifts
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Intrinsic Shape Variation of Quiescent Galaxies from Redshift 2.5 to 0.5
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作者 Lijun Chen Hong-Xin Zhang 《Research in Astronomy and Astrophysics》 2025年第3期123-130,共8页
According to the standard“inside-out”galaxy formation scenario,galaxies first form a dense core and then gradually assemble their outskirts.This implies that galaxies with similar central stellar mass densities migh... According to the standard“inside-out”galaxy formation scenario,galaxies first form a dense core and then gradually assemble their outskirts.This implies that galaxies with similar central stellar mass densities might have evolutionary links.We use the UVJ color-color diagram to select quiescent galaxies in the redshift interval from 0.5 to 2.5 and classify them into different subsamples based on their central stellar mass densities,stellar mass,morphological type and redshift.We then infer the intrinsic axis ratiosμ_(B/A) andμC/A of different subsamples based on the apparent axis ratio q distributions,where A,B,and C refer to,respectively,the major,intermediate and minor axis of a triaxial ellipsoidal model.We find that(1)massive quiescent galaxies have typical intrinsic shapes similarly close to thick oblate structures,withμ_(B/A)0.9,regardless of stellar mass,redshift,or central stellar mass densities,and(2)galaxies at higher redshift are systematically thinner than their lower-redshift counterparts,and(3)when splitting the sample into early type and late type with Sérsic indices,ETGs at higher redshift are slightly more prolate(smaller averageμ_(B/A))than those at lower redshift.Minor mergers of galaxies may have played important roles in the structural evolution of quiescent galaxies found in this work. 展开更多
关键词 GALAXY evolution-galaxies high-redshift-Galaxy FORMATION
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The Impact of Different Effective Models for Star Formation on the Properties of Simulated Milky Way-sized Galaxies
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作者 Yiheng Wu Volker Springel 《Research in Astronomy and Astrophysics》 2025年第1期192-208,共17页
Hydrodynamical cosmological simulations of galaxy formation such as IllustrisTNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming inter... Hydrodynamical cosmological simulations of galaxy formation such as IllustrisTNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming interstellar medium(ISM)has relied on heuristic sub-grid models.However,recent high-resolution simulations of the ISM that directly resolve the regulation of star formation suggest different mean relations for the dependences of pressure and star formation rate on the average gas density.In this study,we adopt such a modern,physically grounded parameterization inspired by the TIGRESS small-scale simulations.We dub this model TEQS and use it for a detailed comparative analysis of the formation and evolution of a Milky Way-sized galaxy when compared with the widely used TNG model.By employing high-resolution simulations in tall box setups,we first investigate the structural differences expected for these two models when applied to different self-gravitating gas surface densities.Our results indicate that TEQS produces considerably thinner gaseous layers and can be expected to form stellar distributions with smaller scale-height than TNG,especially at higher surface density.To test whether this induces systematic structural differences in cosmological galaxy formation simulations,we carry out zoom-in simulations of 12 galaxies taken from the set of Milky Way-sized galaxies that have been studied in the Auriga project.Comparing results for these galaxies shows that disk galaxies formed with the TEQS model have on average very similar stellar mass but are more concentrated in their central regions and exhibit smaller stellar radii compared to those formed with the TNG model.The differences in the scale-heights of the formed stellar disks are only marginal,however,suggesting that other factors for setting the thickness of the disk are more important than the applied ISM equation-of-state model.Overall,the predicted galaxy structure is quite similar for TNG and TEQS despite significant differences in the employed star formation law,demonstrating that feedback processes are more important in regulating the stellar mass than the precise star formation law itself. 展开更多
关键词 GALAXY formation-Galaxy evolution-methods NUMERICAL
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Unveiling the Quenching Mode of Dwarf Galaxies Beyond Redshift z=1 with JWST Image Stacking
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作者 Yubin Li Nan Li +7 位作者 Fengshan Liu Jirong Mao Qifan Cui Jian Ren Pinsong Zhao Hao Mo Qi Song Xin Zhang 《Research in Astronomy and Astrophysics》 2025年第5期136-153,共18页
Recent JWST observations have revealed that dwarf galaxies start to cease star formation at redshifts z>1,yet the quenching process remains unclear.In this study,we selected a large sample of 3405 dwarf galaxies wi... Recent JWST observations have revealed that dwarf galaxies start to cease star formation at redshifts z>1,yet the quenching process remains unclear.In this study,we selected a large sample of 3405 dwarf galaxies with stellar masses below 109.5Me and redshifts ranging from 1.0 to 1.5 across all five CANDELS fields.By utilizing multi-wavelength imaging data from both JWST and HST,we examined the growth patterns and modes of star formation quenching in dwarf galaxies during the cosmic noon era.Based on their specific star formation rates (sS FR),we categorized the sample into three subgroups:star-forming dwarf galaxies below and above the star formation main sequence (SFMS),and quiescent dwarf galaxies.To analyze the UVJ color profiles of these three subgroups of dwarf galaxies,we applied the image stacking technique.This method improves the signal-to-noise ratio and extends the color profiles to the outer regions of the galaxies.Our results show that these galaxies generally exhibit nearly flat stacked color profiles,suggesting that,on average,their growth and star formation quenching patterns are self-similar,differing from those previously observed in dwarf galaxies at lower redshifts.We further discuss the potential roles of internal and external physical processes in the star formation quenching of dwarf galaxies during the cosmic noon period. 展开更多
关键词 galaxies high-redshift-galaxies dwarf-galaxies star formation
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The Fraction of[CⅡ]Emission Originating from Ionized Gas in Local Galaxies
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作者 Jiamin Liu Yinghe Zhao Jin-Ming Bai 《Research in Astronomy and Astrophysics》 2025年第7期28-43,共16页
This paper presents a statistical study of the division of the[CⅡ]158μm line into ionized and neutral components,using a new carbon-to-nitrogen abundance ratio,log(C/N)=0.75,for a sample of 108 local galaxies.We inv... This paper presents a statistical study of the division of the[CⅡ]158μm line into ionized and neutral components,using a new carbon-to-nitrogen abundance ratio,log(C/N)=0.75,for a sample of 108 local galaxies.We investigate the correlation between the ionized-to-total[CⅡ]ratio([CⅡ]_(ionized)/[CⅡ]_(total))and the farinfrared color f60/f100,finding a moderate negative correlation.Additionally,we explore the dependence of[CⅡ]_(ionized)/[CⅡ]_(total)on various physical properties.We find that[CⅡ]_(ionized)/[CⅡ]_(total)exhibits a weak negative correlation with the offset from the main sequence and a moderate negative correlation with the[OⅢ]88μm/[NⅡ]122μm.Furthermore,no significant correlation with molecular gas mass is found.It shows a positive correlation with metallicity.Our results suggest that[CⅡ]_(ionized)/[CⅡ]_(total)is influenced by the ionization parameter,star formation efficiency and metallicity. 展开更多
关键词 ISM:lines and bands galaxies:evolution galaxies:star formation infrared:ISM
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2024 US General Election and Changes in its Party Politics
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作者 Xie Tao 《Contemporary World》 2025年第1期44-48,共5页
The US 2024 general election ended with the Republican Party winning the presidential, House and Senate elections at the same time. In the presidential election, the Republican Party not only won more popular votes in... The US 2024 general election ended with the Republican Party winning the presidential, House and Senate elections at the same time. In the presidential election, the Republican Party not only won more popular votes in over 90% counties than in the 2020 general election, but also won seven highly contested swing States with greater edges. This also marks the first time since 2004 that the Republican Party has won a relative majority of popular votes in the presidential election. 展开更多
关键词 House elections US general election presidential election general election Senate elections republican party Republican Party popular votes
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The Influence of Dark Matter Halos on Galaxies'Orbital Momenta Alignment
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作者 V.Stephanovich W.Godłowski M.Biernacka 《Research in Astronomy and Astrophysics》 2025年第11期21-45,共25页
We examine the consequences of the dark matter halo presence on the alignment of angular momenta of the luminous astronomical objects like galaxies and their clusters.For that we calculate the distribution function of... We examine the consequences of the dark matter halo presence on the alignment of angular momenta of the luminous astronomical objects like galaxies and their clusters.For that we calculate the distribution function of their gravitational fields within the statistical method,generalized to the the presence of dark matter halos.The generalization deals both with direct account for halo component in the form of Navarro,Frenk and White(NFW)profile and indirect influence of dark matter on the tidal interaction between luminous objects.The NFW profile s gravitational field distribution isolates luminous objects within the halo,suppressing mutual interactions,which contradicts observational data and simulations.To address this,we propose a hypothetical short-range interaction,which can be a well of Newtonian(gravitational)nature.Namely,we derive this short-range interaction on the basis of a multipole expansion of the initial Newtonian interaction.Introducing the short-range part in the initial interaction,we arrive at modified quadrupolar intergalaxy interaction,which permits the luminous objects,which are closer than interaction range rc,to effectively interact with each other inside the dark matter halo.This permits us to show that the more clumpy the luminous objects are,the more probably their orbital moments will be aligned.Our theoretical analysis,supported by observational and simulation data(Illustris Project 2013),indicates that dark matter halos significantly alter the gravitational field distribution,affecting angular momenta alignment.We find that while angular momenta alignment increases with cluster richness in galaxy clusters,it does not in superclusters,likely due to the abundant dark matter in superclusters.Our theoretical predictions align well with both observational data and numerical simulations. 展开更多
关键词 Galaxy:formation Galaxy:kinematics and dynamics (cosmology:)dark matter cosmology:theory
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Exploration and Practice of General Education Courses on Cybersecurity in Higher Education Institutions
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作者 Xuejing Zhang Yueqin Li +1 位作者 Fang Yang Jingjing Wu 《Journal of Contemporary Educational Research》 2025年第11期306-310,共5页
Strengthening cybersecurity education for college students holds significant importance in achieving the strategic goal of building China into a cyber power.This article begins by discussing the significance and neces... Strengthening cybersecurity education for college students holds significant importance in achieving the strategic goal of building China into a cyber power.This article begins by discussing the significance and necessity of implementing cybersecurity education for university students.Drawing on disciplinary characteristics and student learning analysis,it presents a comprehensive construction process and countermeasures for a general cybersecurity education course,covering aspects such as teaching content development,teaching resource creation,and pedagogical approaches.The aim is to provide reference and guidance for other universities in developing general cybersecurity education courses. 展开更多
关键词 CYBERSECURITY general education Security awareness
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