A5018654623- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Particle Accelerators and Free-Electron Lasers
- Scientific Research and Discoveries
- Topic Modeling
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- Atomic and Molecular Physics
- Text and Document Classification Technologies
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Neutrino Physics Research
- RNA and protein synthesis mechanisms
Shanghai Astronomical Observatory
2015-2024
Shenzhen Technology University
2024
Shenzhen University
2024
Shandong University of Science and Technology
2024
University of Chinese Academy of Sciences
2022-2023
Jilin University
2022-2023
University of Electronic Science and Technology of China
2023
National University of Singapore
2023
Nagasaki Institute of Applied Science
2022
Xi'an Jiaotong University
2022
The Sloan Digital Sky Survey has validated and made publicly available its First Data Release. This consists of 2099 square degrees five-band (u, g, r, i, z) imaging data, 186,240 spectra galaxies, quasars, stars calibrating blank sky patches selected over 1360 this area, tables measured parameters from these data. data go to a depth r ~ 22.6 are photometrically astrometrically calibrated 2% rms 100 milli-arcsec per coordinate, respectively. cover the range 3800--9200 A, with resolution...
We present the discovery of three new quasars at z > 6 in ∼ 1300 deg2 Sloan Digital Sky Survey imaging data, J114816.64+525150.3 (z = 6.43), J104845.05+463718.3 6.23), and J163033.90+401209.6 6.05). The first two objects have weak Lyα emission lines; their redshifts are determined from positions Lyman break. They only accurate to ∼0.05 could be affected by presence broad absorption line systems. last object has a strength more typical lower redshift quasars. Based on sample six 5.7 that...
We present 5-38 μm mid-infrared spectra at a spectral resolution of R ≈ 65-130 large sample 22 starburst nuclei taken with the Infrared Spectrograph (IRS) on board Spitzer Space Telescope. The show vast range SEDs. silicate absorption ranges from essentially no to heavily obscured systems an optical depth τ9.8 ~ 5. slopes can be used discriminate between and AGN powered sources. monochromatic continuum fluxes 15 30 enable remarkably accurate estimate total infrared luminosity starburst. find...
We present spectra taken with the Infrared Spectrograph on Spitzer covering 5-38 micron region of ten Ultraluminous Galaxies (ULIRGs) found in IRAS Bright Galaxy Sample. Among BGS ULIRGs, we find a factor 50 spread rest-frame mid to far-infrared spectral slope. The 9.7 silicate optical depths range from less than 0.4 more 4.2, implying line sight extinctions A(V) ~ 8 - 78 mag. There is evidence for water ice and hydrocarbon absorption C2H2 HCN features four possibly six 10 indicating...
Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models active galactic nuclei (AGNs) and postulated to account for an appreciable fraction cosmic hard X-ray background. We present a sample 291 AGNs at redshifts 0.3 < Z 0.83 from spectroscopic data Sloan Digital Sky Survey. These objects have narrow (FWHM 2000 km s-1), high equivalent width lines with high-ionization line ratios. describe selection procedure...
We present a new diagnostic diagram for mid-infrared spectra of infrared galaxies based on the equivalent width 6.2 μm PAH emission feature and strength 9.7 silicate feature. Based positions in this diagram, we classify into nine classes ranging from continuum-dominated AGN hot dust PAH-dominated starburst to absorption-dominated deeply obscured galactic nuclei. find that are systematically distributed along two distinct branches: one starburst-dominated nuclei spectra. The separation...
We have compiled a large sample of low-redshift active galactic nuclei (AGN) identified via their emission line characteristics from the spectroscopic data Sloan Digital Sky Survey. Since lines are often contaminated by stellar absorption lines, we developed an objective and efficient method subtracting continuum every galaxy spectrum before making measurements. The distribution measured H$\alpha$ Full Width at Half Maxima values galaxies is strongly bimodal, with two populations separated...
We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in accretion disks AGNs, few hundred gravitational radii (RG) supermassive black hole. investigate properties candidate disk emitters with respect full AGNs over same redshifts, focusing on optical, radio, and X-ray flux, broad-line shapes narrow-line equivalent widths, flux ratios. find that have medium...
Full low resolution (65
We present a {\em Spitzer}-based mid-infrared study of large sample Blue Compact Dwarf galaxies (BCD) using the Infrared Spectrograph (IRS), including first mid-IR spectrum IZw18, archetype for BCD class and among most metal poor known. show spectra Polycyclic Aromatic Hydrocarbon (PAH) emission in low-metallicity environment. find that equivalent widths (EW) PAHs at 6.2, 7.7, 8.6 11.2 $μ$m are generally weaker BCDs than typical starburst fine structure line ratio, [NeIII]/[NeII], has weak...
The emission line luminosity function of active galactic nuclei (AGN) is measured from about 3000 AGN included in the main galaxy sample Sloan Digital Sky Survey within a redshift range $0
We report the spectroscopic detection of silicate emission at 10 and 18 μm in five PG quasars, first these two features galaxies outside Local Group. This finding is consistent with unification model for active galactic nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a feature mid-infrared. The strengths detected range from 0.12 to 1.25 times continuum 0.20 0.79 μm. grain temperatures inferred ratio under assumption optically thin 140 220 K.
We study the escape of Ly-alpha photons from emitting galaxies (LAEs) and overall galaxy population using a sample 99 LAEs at 1.9<z<3.8 detected through integral-field spectroscopy blank fields by HETDEX Pilot Survey. For 89 showing counterparts in deep broad-band images we measure rest-frame UV luminosity slope, which use to estimate E(B-V) under assumption constant intrinsic slope for LAEs. These two quantities are used dust-corrected star formation rate (SFR). A comparison between...
A sample of 196 AGNs and ULIRGs observed by the Infrared Spectrograph (IRS) on Spitzer is analyzed to study distribution strength 9.7 micron silicate feature. Average spectra are derived for quasars, Seyfert 1 2 AGNs, ULIRGs. We find that quasars characterized features in emission 1s equally or weak absorption. 2s dominated absorption, strong absorption (mean apparent optical depth about 1.5). Luminosity distributions show luminosities at rest frame 5.5 similar most luminous almost 10^5...
We present a catalog of emission-line galaxies selected solely by their fluxes using wide-field integral field spectrograph. This work is partially motivated as pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). describe observations, reductions, detections, redshift classifications, line fluxes, and counterpart information 397 detected over 169 sq.arcmin with 3500-5800 Ang. bandpass under 5 full-width-half-maximum (FWHM) spectral resolution. The survey's...
We present spectra taken with the Infrared Spectrograph on Spitzer covering 5-38micron region of three Ultraluminous Galaxies (ULIRGs): Mrk 1014 (z=0.163), and 463 (z=0.051), UGC 5101 (z=0.039). The continua show strong silicate absorption suggesting significant optical depths to nuclei at 10microns. also shows clear presence water ice in absorption. PAH emission features are seen both 5101, including 16.4micron line 5101. fine structure lines consistent dominant AGN power sources 463. In we...
The silicate cross section peak near 10 μm produces emission and absorption features in the spectra of dusty galactic nuclei observed with Spitzer Space Telescope. Especially ultraluminous infrared galaxies, feature can be extremely deep, as IRAS 08572+3915 illustrates. A foreground screen obscuration cannot reproduce this feature, even at a large optical depth. Instead, deep requires nuclear source to deeply embedded smooth distribution material that is both geometrically optically thick....
We present mid-infrared spectra of the nearby, Ultraluminous Infrared Galaxy NGC 6240 taken with IRS on Spitzer. The spectrum is dominated by strong fine-structure lines, rotational H2 and PAH emission features. line fluxes suggest molecular gas at a variety temperatures. A simple two-temperature fit to S(0) through S(7) lines implies mass 6.7E6 solar masses T=957K 1.6E9 T=164K, or about 15% total in this system. Noteably, we have detected [NeV] 14.3 micron line, flux 5E-14 erg/cm^2/s,...
We have measured mid-infrared radiation from an orientation-unbiased sample of 3CRR galaxies and quasars at redshifts 0.4 ≤ z 1.2 with the IRS MIPS instruments on Spitzer. Powerful emission (L24 μm > 1022.4 W Hz-1 sr-1) was detected all but one sources. fit Spitzer data other measurements literature synchrotron dust components. The provide powerful constraints fits. At 15 μm, are typically 4 times brighter than radio same isotropic power. Based our fits, half this difference can be...
Galaxy-galaxy mergers and close interactions have long been regarded as a viable mechanism for channeling gas toward the central supermassive black holes (SMBHs) of galaxies which are triggered active galactic nuclei (AGNs). AGN pairs, in SMBHs galaxy merger both active, expected to be common from such events. We conduct systematic study 1286 pairs at z ~ 0.1 with line-of-sight velocity offsets dv < 600 km/s projected separations r_p 100 kpc, selected Seventh Data Release Sloan Digital Sky...
We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction varies galaxy physical parameters, i.e. M*, SFR sSFR. According to their sSFR, we further classify these into three categories, 10 star-forming, 26 "Green Valley" 30 quiescent ones. different types are in that star-forming ones have positive gradient D4000 higher gas-phase metallicity, while green valley/quiescent negative gradients lower metallicity on average. There is...
Type II quasars are luminous active galactic nuclei (AGNs) whose centers obscured by large amounts of gas and dust. In this paper we present three-band Hubble Space Telescope images nine type with redshifts 0.2 < z 0.4 selected from the Sloan Digital Sky Survey based on their emission-line properties. The intrinsic luminosities these AGNs estimated to be -24 > MB -26, but optical obscuration allows host galaxies studied unencumbered bright nuclei. Each object has been imaged in three...
We present an atlas of Spitzer/IRS high resolution (R~600) 10-37um spectra for 24 well known starburst galaxies. The are dominated by fine-structure lines, molecular hydrogen and emission bands polycyclic aromatic hydrocarbons. Six out the eight objects with a AGN component show excitation [NeV] line. This line is also seen in one other object (NGC4194) with, priori, no component. In addition to strong hydrocarbon features this wavelength range (11.3, 12.7, 16.4um), reveal weak at 10.6,...
We present the survey design, data reduction, and spectral fitting pipeline for VIRUS-P Exploration of Nearby Galaxies (VENGA). VENGA is an integral field spectroscopic survey, which maps disks 30 nearby spiral galaxies. Targets span a wide range in Hubble type, star formation activity, morphology, inclination. The data-cubes have 5.6'' FWHM spatial resolution, ~5A sample 3600A-6800A range, cover large areas typically sampling galaxies out to ~0.7 R_25. These can be used produce 2D rate,...