OPC Categories

IMPORTANT NOTE: As of Period 110 ESO has moved from the OPC categories to the Scientific Keywords. The OPC categories listed below are therefore obsolete. This page will be kept active only for a limited number of semesters, and for pure historical reasons.

The list of Scientific Keywords is included in the p1 and User Portal interfaces in the form of pull-down menues.





A1 Galaxies in their environment (e.g. galaxies in groups and clusters, merging galaxies,
galaxy interactions, ram-pressure stripping of galaxies in groups and clusters)
A2 Global properties of galaxy groups, clusters and proto-structures including the intracluster
A3 Dark matter and gravitational lensing
A4 Intergalactic medium, circumgalactic medium and intervening absorption systems
(e.g. Lyman alpha clouds, damped Lyman alpha systems and associated galaxies)
A5 Discovery surveys and the statistical study of galaxy properties (e.g. spectroscopic
and redshift surveys, identifications, large scale structure, galaxy luminosity function
and mass function, surveys for active galactic nuclei)
A6 Reionization and cosmic dawn (probes of reionization, galaxies in the epoch of
A7 Cosmological parameters (e.g. distance scale, dark energy, fundamental physics).


B1 The Milky way and local group galaxies
B2 Resolved and unresolved stellar populations in galaxies beyond the Local Group (e.g.
stellar metallicity, star formation histories)
B3 Galaxy structure, dynamics and kinematics (e.g. bulges, disks, morphology,
in/outflows, dark matter inside galaxies, stellar orbits)
B4 Dwarf galaxies, stellar clusters in galaxies and satellite galaxies
B5 Galactic centre, galaxy nuclei and supermassive black holes
B6 Physics of Active Galactic Nuclei
B7 Interstellar medium and star formation in galaxies (e.g., in/outflows, starburst
galaxies, gas-phase metallicity, dust in galaxies)


C1 Gas and dust, giant molecular clouds, cool and hot gas, diffuse and translucent clouds
C2 Chemical processes in the interstellar medium
C3 Star forming regions, globules, protostars, HII regions
C4 Pre-main-sequence stars (massive PMS stars, Herbig Ae/Be stars and T Tauri stars)
C5 Outflows, stellar jets, HH objects
C6 Main-sequence stars with circumstellar matter, early evolution
C7 Young binaries, brown dwarfs, exosolar planet searches
C8 Solar system (planets, comets, small bodies)


D1 Main-sequence stars
D2 Post-main-sequence stars, giants, supergiants, AGB stars, post-AGB stars
D3 Pulsating stars and stellar activity
D4 Mass loss and winds
D5 Supernovae, pulsars
D6 Planetary nebulae, nova remnants and supernova remnants
D7 Pre-white dwarfs and white dwarfs, neutron stars
D8 Evolved binaries, black-hole candidates, novae, X-ray binaries, CVs
D9 Gamma-ray and X-ray bursters
D10 OB associations, open and globular clusters, extragalactic star clusters
D11 Individual stars in external galaxies, resolved stellar populations
D12 Distance Scale - stars


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