Sharpless catalogue

Sharpless catalogue
Name	Sharpless catalogue
Type	Astronomical catalogue
Author	Stewart Sharpless
Published	1953, 1959
Entries	313 (original), 134 (revised)
Subject	H II regions, emission nebulae

Sharpless catalogue The Sharpless catalogue is a mid-20th-century astronomical listing of Galactic H II regions and emission nebulae compiled by astronomer Stewart Sharpless. It provides positions, angular sizes, and basic morphological notes for ionized nebulae across the Milky Way, serving as a foundational reference for optical, radio, and infrared studies by observatories and researchers worldwide.

Introduction

The catalogue was created to systematize emission nebulae observed with photographic surveys and to support work at institutions such as the Mount Wilson Observatory, Palomar Observatory, Yerkes Observatory, Harvard College Observatory, and Kitt Peak National Observatory. It complements other catalogues like the Messier catalogue, the New General Catalogue, and the RCW catalogue while being used alongside surveys from the Palomar Observatory Sky Survey and instruments on Palomar Hale Telescope and Kitt Peak 4-meter Telescope. Its entries have been cross-referenced in modern databases maintained by organizations including the European Southern Observatory, the Space Telescope Science Institute, and the National Radio Astronomy Observatory.

History and compilation

The initial compilation was published in the 1950s by Stewart Sharpless during his tenure at the University of Chicago and based on photographic plates from projects coordinated with the Carnegie Institution for Science and the California Institute of Technology. The first list emerged in 1953 and was substantially revised in 1959 to include additional detections and corrected positions, influenced by work from astronomers at Palomar Observatory and the photographic inventories of Cecilia Payne-Gaposchkin's era. Subsequent updates and cross-identifications were made in the context of radio continuum mapping by teams at the Max Planck Institute for Radio Astronomy and by infrared follow-up with instruments onboard missions like the Infrared Astronomical Satellite and later space telescopes such as Spitzer Space Telescope and Wide-field Infrared Survey Explorer.

Contents and designation system

Entries in the catalogue are indexed by a simple numeric system reflecting Sharpless's ordering, used in observational proposals at facilities including the Hale Telescope, the Very Large Telescope, and the Atacama Large Millimeter/submillimeter Array. Each entry provides a right ascension and declination epoch, angular extent, and comments on morphology or association with stellar clusters like those catalogued by Collins, with many entries corresponding to emission regions ionized by OB associations catalogued by astronomers affiliated with Royal Observatory Edinburgh and Lick Observatory. The designation scheme is straightforward and widely adopted in multiwavelength studies conducted by teams at the Jet Propulsion Laboratory and the Harvard–Smithsonian Center for Astrophysics.

Notable objects

Several catalogue entries correspond to well-known nebulae widely studied by researchers at the Cerro Tololo Inter-American Observatory, the Anglo-Australian Observatory, and the European Southern Observatory. These include nebulae associated with massive star-forming regions observed in projects led from University of Cambridge and Massachusetts Institute of Technology groups, and compared with classical objects recorded in the New General Catalogue and imaged by the Hubble Space Telescope. Many Sharpless objects align with radio sources identified by the Very Large Array and molecular cloud complexes traced by teams at the Institut de Radioastronomie Millimétrique.

Observational methods and instrumentation

Discovery and characterization used wide-field photographic plates from surveys like the Palomar Observatory Sky Survey captured on instruments at Palomar Observatory and reduced with techniques refined at the Harvard College Observatory. Modern follow-up employs optical spectrographs on telescopes such as the Keck Observatory, integral field units developed at the European Southern Observatory, radio interferometers including the Very Large Array, and millimeter facilities like the Atacama Large Millimeter/submillimeter Array. Infrared observations from missions such as the Spitzer Space Telescope and the Herschel Space Observatory have been crucial for penetrating dust associated with Sharpless entries and for studies by researchers at institutions like the Jet Propulsion Laboratory and Space Telescope Science Institute.

Scientific significance and applications

The catalogue has been instrumental for studies of massive star formation, H II region physics, and Galactic structure by research groups at the University of Arizona, Ohio State University, Princeton University, and the Max Planck Institute for Astronomy. It facilitates cross-wavelength analyses combining optical emission-line diagnostics used by teams at the National Optical Astronomy Observatory with radio continuum and molecular line surveys from the National Radio Astronomy Observatory and Institut de Radioastronomie Millimétrique. Sharpless entries serve as target lists for investigations of ionization fronts, stellar feedback, and triggered star formation examined in work associated with the Royal Astronomical Society, the American Astronomical Society, and collaborative programs at the European Southern Observatory and Space Telescope Science Institute.

Category:Astronomical catalogues