HELIUM SEDIMENTATION AND THE ULTRAVIOLET UPTURN IN BRIGHTEST CLUSTER GALAXIES

Journal Article · Sun Nov 01 04:00:00 EST 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/705/1/L58· OSTI ID:21378391

Fang, Peng ^[1]; Nagai, Daisuke ^[2]

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1. Theoretical Astrophysics, 1200 East California Boulevard, 350-17, Pasadena, CA 91125 (United States)
2. Department of Physics, Yale University, P.O. Box 208210, New Haven, CT 06520-8120 (United States)

Recent observations with the Galaxy Evolution Explorer (GALEX) show strong unexpected ultraviolet (UV) excess in the spectrum of brightest cluster galaxies (BCGs). It is believed that the excess UV signal is produced by old and evolved core-He burning stars, and the UV flux strength could be greatly enhanced if the progenitor stars have a high value of He abundance. In this work, we propose that the sedimentation process can greatly enhance the He abundance in BCGs. Our model predicts that the UV flux strength is stronger in more massive, low-redshift, and dynamically relaxed BCGs. These predictions are testable with the current generation of GALEX+SDSS observations.

• OSTI ID: 21378391
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 705; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GALAXIES
GALAXY CLUSTERS
GASES
HELIUM
NONMETALS
RADIATIONS
RARE GASES
RED SHIFT
SEDIMENTATION
STARS
ULTRAVIOLET RADIATION