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The broad wing of the [O Ⅲ] λ5007 emission line in active galactic nuclei

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Research in Astronomy and Astrophysics 2014年第8期14卷 913-922页

作者： Zhi-Xin Peng Yan-Mei Chen qiu-sheng gu Kai Zhang School of Astronomy and Space Science Nanjing University Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of Sciences

We use a sample of type 2 active galactic nuclei （AGNs） from SDSS DR7 in which the [O Ⅲ] ）λ5007 emission line can be modeled by two Gaussian components, a broad wing plus a narrow core, to investigate the origin of the broad wing and the connection between the velocity shift of the broad wing and the physical parameters of AGNs, as well as their host galaxies. We find that the flux of the wing components is statistically roughly equal to that of the core components. However, the velocity shift of the wing component has only weak, if any, correlations with the physical properties of AGNs and the host galaxies, such as bolometric luminosity, the Eddington ratio, the mass of supermassive black holes, D4000, H3A or stellar mass. Comparing the velocity shift from our type 2 AGN sample to that from the type 1 sample in Zhang et al., we suggest that the [O Ⅲ]] broad wing originates from outflow.

关键词： galaxies: active -- galaxies: Seyfert -- quasars: emission lines

The Origin of Infrared Emission from the Infrared Luminous Galaxy NGC 4418

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Chinese Journal of Astronomy and Astrophysics 2005年第2期5卷 117-125页

作者： Lei Shi and qiu-sheng gu Department of Astronomy, Nanjing University, Nanjing 210093 qsgu@*** Department of Astronomy Nanjing University Nanjing 210093

We present a study of the origin of infrared (IR) emission in the opticallynormal, infrared luminous galaxy NGC 4418. By decomposing the stellar absorption features andcontinua in the range of 3600-8000 A from the Sloan Digital Sky Survey into a set of simple stellarpopulations, we derive the stellar properties for the nuclear region of NGC 4418. We compare theobserved infrared luminosity with the one derived from the starburst model, and find thatstar-forming activity contributes only 7% to the total IR emission, that as the IR emission regionis spatially very compact, the most possible source for the greater part of the IR emission is adeeply embedded AGN, though an AGN component is found to be unnecessary for fitting the opticalspectrum.

关键词： galaxies: general galaxies: active galaxies: stellar content galaxies:individual (NGC 4418)

Elliptical Galaxies with Emission Lines from the Sloan Digital Sky Survey

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Chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 15-24页

作者： Ying-He Zhao qiu-sheng gu Zhi-Xin Peng Lei Shi Xin-Lian Luo qiu-He Peng Department of Astronomy Nanjing University Nanjing 210093

As part of a study of star formation history along the Hubble sequence, we present here the results for 11 elliptical galaxies with strong nebular emission lines. After removing the dilution from the underlying old stellar populations by use of stellar population synthesis model, we derive the accurate fluxes of all the emission lines in these objects, which are then classified, using emission line ratios, into one Seyfert 2, six LINERs and four HII galaxies. We also identify one HII galaxy （A1216＋04） as a hitherto unknown Wolf-Rayet galaxy from the presence of the WolfRayet broad bump at 4650A. We propose that the star-forming activities in elliptical galaxies are triggered by either galaxy-galaxy interaction or the merging of a small satellite/a massive star cluster, as has been suggested by recent numerical simulations.

关键词： Galaxies: elliptical and lenticular cD Galaxies: starburst - Galaxies:individual: A1212+06 A1216+04 CGCG13-83 IC 225

Low-ionization galaxies and evolution in a pilot survey up to z=1

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Research in Astronomy and Astrophysics 2011年第3期11卷 245-270页

作者： Edmond Giraud qiu-sheng gu Jorge Melnick Hernan Quintana Fernando Selman Ignacio Toledo Paula Zelaya LPTA Universit6 Montpellier 2 - CNRS/IN2P3 34095 Montpellier France edmond.giraud@ lpta. in2p3.fr Department of Astronomy Nanjing University Nanjing 210093 China European Southern Observatory /klonso de Cbrdova 3107 Santiago Chile Department of Astronomy and Astrophysics R Universidad Catolica de Chile Casilla 306Santiago Chile

We present galactic spectroscopic data from a pencil beam of 10.75×7.5 centered on the X-ray cluster RXJ0054.0–2823 at z=*** study the spectral evolution of galaxies from z=1 down to the cluster redshift in a magnitude-limited sample at R≤23,for which the statistical properties of the sample are well *** divide emission-line galaxies into star-forming galaxies,Low Ionization Nuclear Emission line Regions（LINERs） ,and Seyferts by using emission-line ratios of[OII],Hβ,and[OIII],and derive stellar fractions from population synthesis models. We focus our analysis on absorption and low-ionization *** absorption-line galaxies,we recover the well-known result that these galaxies have had no detectable evolution since z～0.6-0.7,but we also find that in the range z=0.65-1,at least 50% of the stars in bright absorption systems are younger than 2.5 *** absorption-line galaxies in the cluster at z=0.29 also had significant star formation during the previous 2-3 Gyr,but their brighter counterparts seem to be only composed of old *** z～0.8,our dynamically young cluster had a truncated *** result seems to be consistent with a scenario where the final assembly of E/S0 took place at *** the volume-limited range 0.35≤z≤0.65,we find that 23% of the early-type galaxies have LINER-like spectra with Hβin absorption and have a significant component of A *** vast majority of LINERs in our sample have significant populations of young and intermediate-aged stars and are thus not related to AGNs,but to the population of‘retired galaxies’recently identified by Cid Fernandes et *** the Sloan Digital Sky Survey（SDSS） .Early-type LINERs with various fractions of A stars and E＋A galaxies appear to play an important role in the formation of the red sequence.

关键词： cosmology:observations—galaxies:evolution—large scale structures —evolution—RX J0054.0–2823

The morphology, kinematics and metallicity of blue-core galaxies

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Research in Astronomy and Astrophysics 2019年第6期19卷 51-62页

作者： Yong-Yun Chen Yan-Mei Chen qiu-sheng gu Yong Shi Long-Ji Bing Xiao-Ling Yu School of Astronomy and Space Science Nanjing University Nanjing 210093 China Collaborative Innovation Center of Modern Astronomy and Space Exploration Nanjing 210093 China

We select 107 blue-core galaxies from the MaNGA survey, studying their morphology, kinematics as well as the gas-phase metallicity. Our results are as follows:(i) In our sample, 26% of blue-core galaxies have decoupled gas-star kinematics, indicating external gas accretion;15% have bar-like structure and 8% show post-merger features, such as tidal tails and irregular gas/star velocity field. All these processes/features, such as accreting external misaligned gas, interaction and bar, can trigger gas inflow. Thus the central star-forming activities lead to bluer colors in their centers(blue-core galaxies).(ii) By comparing with the SDSS DR7 star-forming galaxy sample, we find that the blue-core galaxies have higher central gas-phase metallicity than what is predicted by the local mass-metallicity relation. We explore the origin of the higher metallicity, finding that not only the blue-core galaxies, but also the flat-gradient and red-core galaxies all have higher metallicity. This can be explained by the combined effect of redshift and galaxy color.

关键词： galaxies abundances-galaxies formation-galaxies structure

Nuclear Starburst Activity in the Seyfert 2 Galaxy NGC 2273

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Chinese Journal of Astronomy and Astrophysics 2003年第3期3卷 203-211页

作者： qiu-sheng gu, Lei Shi, Shi-Jun Lei, Wen-Hao Liu and Jie-Hao Huang Department of Astronomy, Nanjing University, Nanjing 210093 qsgu@*** Department of Astronomy Nanjing University Nanjing 210093

We present spectrophotometric results of the Seyfert 2 galaxy NGC 2273. Thepresence of high-order Balmer absorption lines (H8, H9, H10) and weak equivalent widths of CaII Kλ3933, CN λ4200, G-band λ4300 and MgIb λ5173 clearly indicate recent star-forming activity inthe nuclear region. Using a simple stellar population synthesis model, we find that for the bestfit, the contributions of a power-law featureless continuum, an intermediate-age (～ 10~8 yr) and anold (> 10~9 yr) stellar population to the total light at the reference normalization wavelength are10.0%, 33.4% and 56.6%, respectively. The existence of recent starburst activity is also consistentwith its high far-infrared luminosity (log L_(FIR.)/L☉ = 9.9), its infrared color indexes[α(25,60) = ― 1.81 and α(60,100) = ― 0.79, typical values for Seyfert galaxies withcircumnuclear starburst], and its q-value (2.23, ratio of infrared to radio flux, very similar tothat of normal spirals and starburst galaxies). Byrd et al. have suggested that NGC 2273 might haveinteracted with NGC 2273B in less than 10~9 yr ago, so the starburst activity in this galaxy couldhave been triggered by tidal interaction, as indicated in recent numerical simulations.

关键词： galaxies: seyfert galaxies: starburst galaxies: stellar content

Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

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Journal of Iron and Steel Research International 2024年第4期31卷 828-837页

作者： gu-jun Chen sheng-ping He College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Single argon bubble dynamics in liquid steel under Ruhrstahl-Heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure *** simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,*** simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be *** primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic *** the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,*** bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

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Journal of Iron and Steel Research International 2024年第7期31卷 1661-1667页

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-Heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth

Analysis of China's Electricity Price and Electricity Burden of Basic Industries under the Carbon Peak Target before 2030

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 481-491页

作者： Yue qiu Suyang Zhou Wei gu Xiao-Ping Zhang School of Electrical Engineering Southeast UniversityNanjingChina School of Electronic Electrical and System EngineeringUniversity of BirminghamU.K.

The Chinese government is deepening reformation of electricity prices during the 14th Five Year Plan period and has set a carbon emission reduction target of reaching carbon peak before *** this context,will the carbon emission target influence electricity pricing and will electricity price influence competitiveness of Chinese main industries are two questions needing to be *** paper compares China's electricity price level with the selected major countries in the world,and four typical industries are selected to evaluate their electricity burden ***,the correlation between residential electricity price and industrial electricity price and the influencing factors is analyzed,from the perspectives of scale,structure and *** to the model obtained by regression analysis,the electricity price level and corresponding residential and industrial electricity burden in 2025 and 2030 are *** Terms-Electricity burden,industrial electricity price,regression analysis,residential electricity price.

关键词： Electricity burden industrial electricity price regression analysis residential electricity price