interstellar extinction

interstellar extinction
Name	Interstellar extinction
Type	Astronomical phenomenon
Discovered	19th century
Discoverer	Gustav Kirchhoff; observations by William Herschel; theoretical work by Hermann von Helmholtz
Related	Interstellar medium, Interstellar dust, Extinction curve

Contents

interstellar extinction Interstellar extinction describes the dimming and reddening of light from astronomical sources due to absorption and scattering by dust and gas in the Interstellar medium, a process first inferred in studies by William Herschel, discussed in the context of spectroscopy by Gustav Kirchhoff, and later formalized through work associated with Hermann von Helmholtz and observers at institutions like the Royal Observatory, Greenwich and the Royal Astronomical Society. It affects observations across campaigns by teams at facilities such as the European Southern Observatory, the Palomar Observatory, and the Keck Observatory, and it is a critical factor in surveys conducted by missions like Hubble Space Telescope, Gaia (spacecraft), and Spitzer Space Telescope.

Overview

Interstellar extinction arises within the Interstellar medium where populations of Interstellar dust grains and atoms in regions studied by researchers at the Max Planck Institute for Astronomy and the Harvard–Smithsonian Center for Astrophysics remove and scatter photons from sources including stars cataloged in projects led by the Royal Astronomical Society, targets of the Sloan Digital Sky Survey, and nebulae observed by teams at the Space Telescope Science Institute. The phenomenon is quantified using parameters employed by collaborations like the Two Micron All Sky Survey and the Atacama Large Millimeter Array and is essential for interpreting data from campaigns associated with the European Space Agency and the National Aeronautics and Space Administration.

Extinction is produced by absorption and scattering by particles whose properties were characterized in laboratory programs affiliated with the Royal Society and modeled using theories advanced by figures connected to the Cavendish Laboratory and the Kavli Institute for Theoretical Physics. Dust components include silicates and carbonaceous grains inferred from spectra recorded by the Infrared Space Observatory and the James Webb Space Telescope, and molecular species such as polycyclic aromatic hydrocarbons identified in studies at the Max Planck Institute for Radio Astronomy and the California Institute of Technology. Processes such as Mie scattering, advocated in treatments taught at the University of Cambridge and the Massachusetts Institute of Technology, and resonant absorption, investigated by teams at the Jet Propulsion Laboratory, govern wavelength-dependent behavior described in models developed at the University of Chicago and the University of Oxford.

The extinction curve, empirically derived in programs like those of the European Southern Observatory and the Keck Observatory, shows characteristic features such as the 2175 Å bump first reported in data reduced at institutions including the Carnegie Institution for Science and analyzed by astronomers affiliated with the California Institute of Technology and the University of Pennsylvania. Ultraviolet to infrared trends are mapped in surveys like the Two Micron All Sky Survey and the Wide-field Infrared Survey Explorer, and theoretical interpretations have been advanced by researchers at the Max Planck Institute for Astronomy and the University of California, Berkeley. Empirical parameterizations such as those used in studies from the Space Telescope Science Institute and groups at the Harvard–Smithsonian Center for Astrophysics relate selective extinction to total extinction in analyses conducted by teams at the National Optical Astronomy Observatory and the European Space Agency.

Measurements employ photometry and spectroscopy from observatories including the Hubble Space Telescope, Very Large Telescope, and the Subaru Telescope and use standard candles like Cepheids and RR Lyrae studied in projects at the Space Telescope Science Institute and the Royal Astronomical Society. Reddening maps have been produced by collaborations behind the Sloan Digital Sky Survey, the Pan-STARRS project, and the Gaia (spacecraft) mission, with calibration based on stellar atlases from the Harvard College Observatory and extinction laws refined by teams at the Max Planck Institute for Astronomy. Techniques include star-count methods pioneered in observatories like the Royal Observatory, Greenwich and nebular line diagnostics applied in work at the Instituto de Astrofísica de Canarias.

Extinction biases distance estimates central to programs at the European Southern Observatory and the Space Telescope Science Institute, affects color–magnitude diagrams used by researchers at the University of Cambridge and the University of Tokyo, and introduces systematic errors in cosmological probes pursued by teams at the Kavli Institute for Cosmology and the Lawrence Berkeley National Laboratory. Corrections rely on extinction maps from the Planck (spacecraft) and catalogs from the Sloan Digital Sky Survey, and on reddening laws developed in studies at the Harvard–Smithsonian Center for Astrophysics and the Max Planck Institute for Astronomy to recover intrinsic properties of objects observed by facilities such as the Gemini Observatory and the Keck Observatory.

Extinction varies across environments from diffuse regions studied by the National Radio Astronomy Observatory to dense clouds observed by the Atacama Large Millimeter Array and star-forming complexes examined by investigators at the Space Telescope Science Institute and the Max Planck Institute for Astrophysics. Variations correlate with environments cataloged in surveys like the Two Micron All Sky Survey and influenced by processes traced in observations from the Herschel Space Observatory and the Spitzer Space Telescope, with regional studies conducted by teams at the Instituto de Astrofísica de Canarias and the California Institute of Technology.

Early recognition of obscuration came from surveys by William Herschel and analyses at the Royal Observatory, Greenwich, followed by spectroscopic foundations laid with contributions linked to Gustav Kirchhoff and discussions in forums of the Royal Society. Quantitative extinction laws and extinction curve features were established through observational programs at institutions such as the Carnegie Institution for Science, the Harvard–Smithsonian Center for Astrophysics, and the Max Planck Institute for Astronomy, while large-scale mapping and modern parameterizations have been delivered by collaborations behind the Sloan Digital Sky Survey, the Gaia (spacecraft) mission, and the Planck (spacecraft) team.

Category:Astronomical phenomena