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Title: GAUSSIAN RANDOM FIELD: PHYSICAL ORIGIN OF SERSIC PROFILES

While the Sersic profile family provides adequate fits for the surface brightness profiles of observed galaxies, its physical origin is unknown. We show that if the cosmological density field is seeded by random Gaussian fluctuations, as in the standard cold dark matter model, galaxies with steep central profiles have simultaneously extended envelopes of shallow profiles in the outskirts, whereas galaxies with shallow central profiles are accompanied by steep density profiles in the outskirts. These properties are in accord with those of the Sersic profile family. Moreover, galaxies with steep central profiles form their central regions in smaller denser subunits that possibly merge subsequently, which naturally leads to the formation of bulges. In contrast, galaxies with shallow central profiles form their central regions in a coherent fashion without significant substructure, a necessary condition for disk galaxy formation. Thus, the scenario is self-consistent with respect to the correlation between observed galaxy morphology and the Sersic index. We further predict that clusters of galaxies should display a similar trend, which should be verifiable observationally.
Authors:
 [1]
  1. Princeton University Observatory, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22365470
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 790; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; CORRELATIONS; DENSITY; FLUCTUATIONS; GALACTIC EVOLUTION; GALAXIES; GALAXY CLUSTERS; GALAXY NUCLEI; INDEXES; MORPHOLOGY; NONLUMINOUS MATTER; RANDOMNESS; STARS