NASA/IPAC  EXTRAGALACTIC  DATABASE

Galaxies and Quasars

Active Galactic Nuclei Active Galaxies Active Nuclei AGN Arakelian Galaxies Barred Spirals BL Lacertae Objects Blazars Blue Compact Galaxies Blue Galaxies Bright Galaxies cD Galaxies Central Galaxies Classification Coma Compact Galaxies Compact Groups Compact Objects Companions D Galaxies Disk Galaxies Double Galaxies Double Radio Sources Dumbbell Galaxies Dusty Ellipticals Dwarf Galaxies Dwarf Irregular Galaxies Dwarf Spheroidal Galaxies Early-Type Galaxies Elliptical Elliptical Galaxies Emission-Line Galaxies Emission-Line Objects Extragalactic Extragalactic Objects Faint Galaxies Faint Nebulae Field Galaxies Giant Galaxies H II Galaxies High-Redshift Galaxies Host Galaxies Infrared Galaxies Interacting Galaxies Isolated galaxies Irregular Irregular Galaxies Late-Type Galaxies Lenticular Galaxies Liners Lopsided Galaxies Low-Luminosity Galaxies Luminous Galaxies Lyman-Alpha Forest Lyman-Alpha Systems Magellanic Clouds Magellanic Stream Markarian Galaxies Massive Galaxies Mergers Morphology Multiple Galaxies N Galaxies Nearby Galaxies Numerical Simulations Pairs of Galaxies Pairs of Quasars Pairs of Radio Galaxies Pairs of Radio Sources Peculiar Peculiar Galaxies Peculiar Objects Polar Ring Galaxies Primeval Galaxies Protogalactic Matter Protogalaxies Quasar-Galaxy Associations Quasar-Galaxy Pairs Quasars Quasi-Stellar Objects Radio Galaxies Radio Identifications Ring Galaxies S0 Galaxies Satellite Galaxies Seyfert Galaxies Shell Galaxies Spiral Galaxies Spirals Starburst Galaxies Starbursts Synchrotron Sources Triaxial Systems UV-Excess Objects X-Ray Galaxies

Galaxy Properties

Absolute Magnitudes Absorption Systems Abundance Gradients Abundances Accretion Ages Angular Diameters Angular Momentum Antitruncation of Disks Apparent Magnitudes Astrometry Atlases Birthrates Bolometric Corrections Bolometric Magnitudes Brightness Brightness Distribution Brightness Temperature Brightness Temperatures Brightness Variations Brightnesses Broad-Band Photometry Bursts BV Photometry C-M Diagrams C-M Relation C-M Relations Catalogues CCD Images CCD Observations CCD Photometry Chemical Composition Chemical Evolution Classification Collapse Colloquia Color Excesses Color Indices Color-Lumin Relation Color-Luminosity Relation Color-Redshift Relation Colors Composition Contraction Cooling Cooling Flows Coordinates Cores Counterparts DDO Photometry Data Archives Data Bases Detection Density Waves Diameter Diameters Differential Rotation Dimensions Disks Disruption Dissipative Processes Distance Distance Indicators Distance Moduli Distance Scale Distances Distribution Double Nuclei Dust Dust Distribution Dust Grains Dynamics Dynamo Theory Ejecta Energetic Particles Energy Content Energy Transfer Ellipticities Energy Distribution Energy Distributions Energy Sources Energy Spectra Envelopes Escape Velocities Evolution Expansion Velocities Explosions Extended Objects Extinction Families Flattening Fluctuations Flux Densities Formation Fourier Analysis Fourier Transforms Fragmentation Fundamental Plane Gas Clouds Gas Content Gas Contents Gas Densities Gas Density Gas Distribution Gas Dynamics Gas Kinematics Gas Motions Gaseous Streams Gas-to-Dust Ratio Gas-to-Dust Ratios Gaseous Disks Geneva Photometry Grains Gravitating Disks Gravitational Collapse Gravitational Instability H Alpha Photometry H Alpha Surveys Heavy Elements Helium Abundance H I Absorption H I Content HI Deficiency H I Observations HI Maps High-Velocity Gas High-Velocity Streams Hot Gas Hot Spots HR Diagrams Hubble Diagram Hubble Diagrams Hubble Sequence Hydrodynamic Models Hydrodynamics Identification Identifications Image Processing Image Quality Image Reconstruction Image Restoration Images Imaging Imaging (Non-Optical) Imaging(Optical/NIR) Inclination Inclinations Integrals of Motion Internal Motions Internal Structure Isophotal Maps Isophotes Kinematics Kinematics (Spatially Resolved) Loops Luminosities Luminosity Luminosity Distribution Luminosity Function Luminous Arcs Magnetic Fields Magnitude-Redshift Relation Magnitudes Maps Mass Mass Density Mass Distribution Mass Ejection Mass Exchange Mass Flow Mass Function Mass Loss Mass Outflow Mass Ratios Mass Transfer Mass-Lumin Relation Mass-Luminosity Relation Mass-Radius Relation Mass-to-Light Ratio Mass-To-Light Ratios Mass-to-Light Ratios Masses Missing Mass Metal Abundances Metal Content Mg2 Indices Models Morphological Types Motions Multi-Object Spectroscopy Multicolor Photometry Multiwavelength Observations Narrow-Band Photometry Nomenclature Nuclei Nucleus Orientation Origin Oblateness Particle Acceleration Photoelectric Photometry Photometric Properties Photographs Photography Photometry Pictures Plasma Plasma Diagnostics Plasma Instabilities Plasma Jets Polarimetry Polarization Population Synthesis Position Angles Positions Radial Velocities Radiation Mechanisms Radiation Pressure Radiation Temperature Radiative Transfer Radius-Luminosity Relation Reddening Redshift Surveys Redshift-Magnitude Relation Redshifts Relativistic Effects Relativistic Electrons Relativistic Beaming Relativistic Fireballs Relativistic Gas Relativistic Jets Relativistic Particles Relativistic Plasma Rotation Rotation Curve Rotation Curves Shape Shock Waves Size Distribution Sizes Sky Surveys Spectra Spectral Classification Spectral Evolution Spectral Indices Spectral Types Spectrophotometry Spectropolarimetry Spectroscopy Spectrum Synthesis Star Counts Star Densities Star Formation Stellar Content Stellar Distribution Stellar Kinematics Streams Stroemgren Photometry Structure Superluminal Motions Surface Brightness Surface Densities Surface Gravity Surface Photometry Surveys Third Integral Three-Color Photometry Tully-Fisher Relation Turbulence Two-Color Diagrams Two-Color Photometry UBV Photometry UBVRI Photometry Variability Velocities Velocity Velocity Curves Velocity Dispersion Velocity Dispersions Velocity Distribution Velocity Field Velocity Fields Velocity Maps Virial Masses Virial Theorem VLA Maps VLA Observations VLB Interferometry Warping

Parts of Galaxies

Accretion Disk Accretion Disks Associations Black Holes Bow Shocks Bridges Broad-Line Regions Central Regions Cold Dust Coronae Dark Clouds Dark Matter Dark Nebulae Double Nuclei Dust Clouds Emission Nebulae Energetic Particles Galactic Bars Galactic Bulges Galactic Centers Galactic Clusters Galactic Coronae Galactic Disks Galactic Halos Galactic Nuclei Galactic Orbits Galactic Planes Galactic Spurs Galactic Winds Galactic X Rays Galaxies Gamma-Ray Bursts Gaseous Nebulae Giant Branches Globular Clusters Globules H I Clouds H I Disk H I Regions H I Shells H II Regions Halos High-Velocity Clouds Hot Spot Nuclei Intercloud Gas Intercloud Matter Interstellar Medium Jets Masers Molecular Clouds Narrow-Line Regions Nebulae OH Clouds OH Masers OH Sources Open Clusters Planetary Nebula Planetary Nebulae Radio Halos Radio Jets Radio Sources Radio Tails Reflection Nebulae Resonances Rings Shells Spiral Arms Spiral Structure Spiral Waves Star Clusters Star-Forming Regions Stellar Associations Supernova Remnants Supernovae Supershells Tails Variable Stars Water Masers Winds

A Stars A Supergiants Ae Stars AGB Stars Algol Systems AM Herculis Stars Am Stars Anomalous Cepheids Ap Stars B Giants B Stars B Supergiants Be Stars Beta Cephei Stars Binaries Binary Stars Blue Objects Blue Stars Blue Stragglers Blue Variables Bright Giants Bright Stars Brown Dwarfs BY Draconis Stars Carbon Stars Cataclysmic Variables Central Stars Cepheids CH Stars Close Binaries Cocoon Stars Collapsing Stars Contact Binaries Cool Stars Degenerate Dwarfs Degenerate Stars Delta Scuti Stars Disk Stars DQ Herculis Stars Dwarfs Dwarf Cepheids Dwarf Novae Early Type Stars Early-Type Stars Early-Type Supergiants Eclipsing Binaries Eclipsing Variables Emission-Line Stars Exciting Stars F Dwarfs F Stars F Supergiants Faint Stars Field Stars FK Comae Stars Flare Stars FU Orionis Stars G Dwarfs G Giants G Supergiants Gamma-Ray Bursters Gamma-Ray Bursts Giant-Branch Stars Giants Guide Stars Halo Stars Helium Stars Helium-Weak Stars Herbig Ae-Be Stars Herbig-Haro Objects Hg-Mn Stars High-Luminosity Stars High-Velocity Stars Horizontal-Branch Stars Horizontal Branches Hot Stars Hubble-Sandage Stars Hydrogen-Deficient Stars Infrared Stars Initial Mass Function Intergalactic Stars Intrinsic Variables Irregular Variables K Giants K Supergiants Late Type Stars Late-Type Dwarfs Late-Type Giants Late-Type Stars Late-Type Subdwarfs Late-Type Supergiants Late-Type Variables Low-Luminosity Stars Low-Mass Stars Long-Period Variables Luminous Blue Variables Luminous Stars M Dwarfs M Giants M Stars M Supergiants Magnetic Stars Main-Sequence Stars Massive Stars Metal-Deficient Dwarfs Metal-Poor Stars Mira Stars Multiple Stars Nearby Stars Neutron Stars Nova-Like Variables Novae O Stars O Subdwarfs O Supergiants OB Associations OB Stars OB Supergiants Of Stars OH-IR Stars Peculiar Stars Population I Stars Population II Stars Population III Stars Post-AGB Stars Pre-Main-Sequence Stars Pregalactic Stars Proper-Motion Stars Protostars Pulsar Pulsar Magnetospheres Pulsars Pulsating Stars Pulsating Variables Quark Stars R CrB Stars Radio Stars Recurrent Novae Red Dwarfs Red Giants Red Stars Red Supergiants Red Variables Reference Stars Rotating Stars RR Lyrae Stars RR Lyrae Variables RS CVn Stars Runaway Stars RV Tauri Stars S Doradus Stars S Stars Semiregular Semiregular Variables Shell Stars Short-Period Variables Solar-Type Stars Soliton Stars Standard Stars Stars Stellar Photometry Subdwarfs Supergiants Supermassive Stars Supernovae Symbiotic Stars T Tauri Stars Triple Stars U Geminorum Stars UV Stars UV-Bright Stars UV-Excess Stars Variable Stars Variables W UMa Stars W Virginis Stars White Dwarfs Wolf Rayet Stars Wolf-Rayet Stars X-Ray Stars Young Stars ZZ Ceti Stars

Optical  

CCD Images CCD Observations CCD Photometry DDO Photometry Geneva Photometry Multi-Object Spectroscopy Multicolor Photometry Multiwavelength Observations Narrow-Band Photometry Optical Bursts Optical Counterparts Optical Depths Optical Design Optical Emission Optical Identification Optical Identifications Optical Interferometry Optical Observations Optical Outbursts Optical Polarization Optical Positions Optical Pulsations Optical Redshift Optical Spectra Optical Structure Optical Systems Optical Thickness Optical Transients Optical Variations Photoelectric Photometry Photometry Photometry(Narrow-Band) Photometry(UVBRI) Stellar Photometry Stroemgren Photometry Three-Color Photometry

Ultraviolet

Extreme UV Extreme UV Astronomy Extreme UV Background Extreme UV Sources Extreme UV Spectra UV UV Absorption UV Astronomy UV Background UV Stars UV-Bright Stars UV Bursts UV Cameras UV Colors UV Continuum UV Excess UV-Excess Objects UV-Excess Stars UV Excesses UV Extinction UV Images UV Light Curves UV Lines UV Luminosities UV Maps UV Objects UV Observations UV Photographs UV Photometry UV Polarization UV Radiation UV Sources UV Spectra UV Spectrographs UV Spectrophotometry UV Spectropolarimetry UV Spectroscopy UV Surveys UV Telescopes UV Variations

X-Rays

Hard X Rays High-Energy Astrophysics Soft X Rays X Rays X-Ray Absorption X-Ray Astronomy X-Ray Background X-Ray Binaries X-Ray Brightness X-Ray Bursters X-Ray Bursts X-Ray Clusters X-Ray Continuum X-Ray Counterparts X-Ray Detectors X-Ray Flares X-Ray Galaxies X-Ray Groups X-Ray Images X-Ray Light Curves X-Ray Lines X-Ray Luminosities X-Ray Maps X-Ray Novae X-Ray Polarization X-Ray Pulsars X-Ray Sources X Ray Sources X-Ray Spectra X-Ray Spectrometers X-Ray Spectroscopy X-Ray Stars X-Ray Structure X-Ray Surveys X-Ray Telescopes X-Ray Transients X-Ray Variations

Gamma Rays

High-Energy Astrophysics Gamma Rays Gamma-Ray Astronomy Gamma-Ray Background Gamma Ray Bursts Gamma-Ray Detectors Gamma-Ray Light Curves Gamma-Ray Lines Gamma-Ray Pulsars Gamma-Ray Sources Gamma-Ray Spectra Gamma-Ray Surveys Gamma-Ray Variations Ultrahigh Energy

Infrared 

Compact Objects Far-IR Radiation FIR Radiation Flux Densities Infrared Absorption Infrared Astronomy Infrared Background Infrared Brightness Infrared Bursts Infrared Cirrus Infrared Colors Infrared Continuum Infrared Excesses Infrared Extinction Infrared Galaxies Infrared Images Infrared Imaging Infrared Interferometry Infrared Light Curves Infrared Lines Infrared Luminosities Infrared Maps Infrared Objects Infrared Photography Infrared Photometers Infrared Photometry Infrared Polarimetry Infrared Polarization Infrared Radiation Infrared Sources Infrared Spectra Infrared Spectrometers Infrared Spectrophotometry Infrared Spectroscopy Infrared Stars Infrared Structure Infrared Surveys

Radio, mm and sub-mm

21 cm Mapping 21 cm Line Fluxes 21 cm Line Widths 21 cm Rotation Curves Aperture Synthesis Bremsstrahlung Compact Objects Compton Effect Compton Scattering Continuum Radiation Contour Maps Cyclotron Radiation Double Radio Sources Extended HI Disks Flux Densities HI Deficiency HI Diameters HI Maps Imaging (Non-Optical) Microwave Background Microwave Radiation MM Radiation Neutral Hydrogen Nonthermal Radiation Nonthermal Sources Pairs of Radio Galaxies Pairs of Radio Sources Radio Absorption Radio Astrometry Radio Astronomy Radio Background Radio Brightness Radio Bursts Radio Continuum Radio Counterparts Radio Double Sources Radio Flares Radio Galaxies Radio Halo Radio Halos Radio Identifications Radio Interferometers Radio Interferometry Radio Jets Radio Light Curves Radio Lines Radio Luminosities Radio Maps Radio Observations Radio Polarization Radio Radiation Radio Recombination Lines Radio Sources Radio Spectra Radio Stars Radio Structure Radio Surveys Radio Tails Radio Telescopes Radio Variations Scintillation Scintillations Sub-MM Astronomy Sub-MM Lines Sub-MM Observations Sub-MM Radiation Sub-MM Spectra Surface Photometry (Non-Optical) Synchrotron Radiation Synchrotron Sources Very-Long-Baseline 21 cm Line 21 cm Observations 21 cm Radiation

Spectroscopy

Absorption Absorption Coefficient Absorption Lines Absorption Spectra Atomic Data Atomic Parameters Atomic Processes Atomic Spectra Balmer Decrement Balmer Lines Bremsstrahlung Broad-Line Regions Calcium Lines Carbon Lines Chemistry CO Compton Effect Compton Scattering Curves-of-Growth Electron Densities Electron Temperatures Electrons Elements Emission Lines Emission Spectra Far-IR Radiation Faraday Rotation Fine Structure Fluorescence Forbidden Lines Fourier Transforms Gamma-Ray Lines Grains H Alpha H Beta Heavy Elements Helium Abundance Helium Lines High-Energy Astrophysics Hydrogen Lines Infrared Lines Ion Abundances Ion Densities Ionization Ionization Structure IR Spectrophotometry Iron Lines Isotopic Abundances Isotopic Composition Line Broadening Line Identifications Line Intensities Line Profiles Line Ratios Lyman Alpha Lyman Beta Lyman Continuum Lyman-Alpha Forest Lyman-Alpha Systems Metal Lines MM Spectra Molecular Abundances Molecular Bands Molecular Lines Molecular Processes Molecular Spectra OH Absorption OH Emission Oxygen Lines Paschen Lines Photodissociation Photoionization Plasma Plasma Diagnostics Protons Radiation Mechanisms Radiation Pressure Radiation Temperature Radiative Transfer Recombination Lines Resonance Lines Silicon Lines Sodium Lines Spectra Spectral Classification Spectral Lines Sub-MM Lines Thomson Scattering Ultrahigh Energy UV Lines X-Ray Lines 21 cm Line 21 cm Observations 21 cm Radiation

Atoms and Molecules

Acetaldehyde Aluminum Amino Acids Ammonia Argon Atomic Carbon Atomic Hydrogen Atomic Oxygen Barium Boron Calcium Carbon Carbon Dioxide Carbon Monosulfide Carbon Monoxide CH CN CNO CNO Anomalies CO Cobalt Chromium Cyanoacetylene Deuterium Elements Formaldehyde Grains HCN Heavy Elements Helium Helium Abundance H I Observations HNC Hydrocarbons Hydrogen Ice Iron Lithium Magnesium Magnesium Oxide Methane Methanol Methyl Cyanide Methylacetylene Molecular Hydrogen Molecular Oxygen Molecules Neon Neutral Gases Neutral Hydrogen Nickel Nitrogen OH Oxygen Polycyclic Hydrocarbons Scandium Silicates Silicon Silicon Sulfide SiO SiO Masers Sodium Strontium Sulfur Sulfur Dioxide Sulfur Monoxide Titanium Monoxide Water Water Vapor Zinc

Pairs, Groups and Clusters

Accretion Alignment Bow Shocks Chains Close Encounters Clustering Clusters of Galaxies Collisions Computer Simulations Contraction Cooling Cooling Flows Correlation Analysis Double Galaxies Double Radio Sources Dynamical Evolution Dynamical Friction Encounters Entropy Fundamental Plane Galaxy Clustering Galaxy Content Galaxy Counts Galaxy Distribution Galaxy Encounters Galaxy Evolution Galaxy Formation Galaxy Groups Galaxy Mergers Galaxy Pairs Galaxy Population Galaxy Voids Gaseous Streams Great Attractor Groups Groups of Galaxies Heat Flow Heating Interacting Interaction Interactions Kinematics Local Group Local Supercluster Membership Metagalaxy Missing Mass N-Body Problem N-Body Simulations Numerical Simulations Nearby Groups Orbits Pairs Pairs of Radio Galaxies Pairs of Radio Sources Peculiar Velocities Protoclusters Radio Double Sources Satellites Separation Separations Shock Waves Small-Scale Structure Superclusters Surface Densities Temperature Distribution Thermal Conductivity Triple Systems Tidal Effects Tidal Evolution Tidal Interaction Tidal Interactions

Intergalactic, Intracluster

Diffuse Background Intergalactic Absorption Intergalactic Clouds Intergalactic Dust Intergalactic Gas Intergalactic Magnetic Field Intergalactic Matter Intergalactic Medium Intergalactic Reddening Intergalactic Space Intracluster Gas Intracluster Matter Ly Alpha Forest

Distances & Large Scale Structure

Alignment Blue Supergiant distance Carbon star distance Cepheid distance Color-Magnitude Diagram distance Counts Distance Distance Indicators Distance Moduli Distance Scale Distances Eclipsing Binary distance Eclipsing Binary distance Filaments Fundamental Plane distance Giant Branch fitting distance Globular Cluster FP distance Globular Cluster Radius distance Globular Cluster SBF distance GCLF distance HII Region Diameter distance Horizontal Branch distance Maser distance Mira/LPV distance Nova distance Post-AGB star distance Power Spectra Proper Motion distance PNLF distance Red Clump distance Red Supergiant Variable Star distance RR Lyrae distance Small-Scale Structure Superclusters SBF distance SN Ia distance SN II Tully-Fisher distance TRGB distance Wolf-Rayet star distance

Cosmology 

Acceleration Anisotropy Antimatter Background Radiation Baryons Bianchi Models Big-Bang Theory Chaos Chaotic Motions Computer Simulations Contraction Correlation Analysis Cosmic Cosmic Abundance Cosmic Density Parameter Cosmic Dust Cosmic Microwave Background Cosmic Rays Cosmic Strings Cosmochronology Cosmological Constant Cosmological Models Cosmological Parameters Cosmology Counts De Sitter Universe Deceleration Deceleration Parameter Density Density Fluctuations Density Perturbations Diffuse Radiation Early Universe Einstein Rings Einstein Universe Element Abundances Elementary Particles Expansion Extragalactic Fundamental Constants Fundamental Parameters Friedmann Universe General Relativity Gravitation Gravitation Theory Gravitational Constant Gravitational Deflection Gravitational Lenses Gravitational Microlensing Gravitational Radiation Gravitational Redshift Gravitational Redshifts Gravitational Waves Gravity Waves High-Energy Astrophysics Hubble Constant Hubble Expansion Hubble Law Inhomogeneities Inflationary Universe Instabilities Isotropy Kaluza-Klein Theory Large-Scale Motions Large-Scale Structure Lyman-Alpha Forest Lyman-Alpha Systems Microwave Background Microwave Radiation Missing Mass Night-Sky Brightness N-Body Problem N-Body Simulations Numerical Simulations Peculiar Velocities Power Spectra Quasar Counts Radio Background Relativistic Astrophysics Relativity Relativity Theory Shock Waves Space-Time Statistics Steady-State Universe Temperature Fluctuations Thermal Evolution Thermal History Thermal Models Thermal Radiation Thermal Stability Thermal Structure Topology Universe