Tracing the history of recent bulge star formation in Active Galactic Nuclei

Research output: Contribution to journalLetterpeer-review


We examine the relation between black hole accretion and bulge star formation as a function of look-back time (τ) in 20 541 obscured active galactic nuclei (AGNs; with redshifts z̄ ~ 0.1 and bolometric luminosities LBol ~ 1043-1045 erg s-1) optically selected from the Sloan Digital Sky Survey (SDSS). To quantify the most recently formed stars with ages less than typical AGN lifetimes, we estimate the differentiated specific star formation rate (SSFRτ) based on population synthesis analysis. The Eddington ratio (λ) is inferred using [O III] λ5007 luminosity and stellar velocity dispersion as proxies for LBol and black hole mass, respectively. We find that when τ < τ 0, SDSS AGNs follow a power law λ ∝ SSFR1.0-1.1τ the relation flattens out when τ > τ 0. The threshold time-scale τ0 is ~0.1 (~1) Gyr in young (old) bulges. The scatter in the power laws is dominated by observational uncertainties. These results may provide useful constraints on models explaining the correlations between AGN activity and bulge star formation.

Original languageEnglish (US)
Pages (from-to)L40-L44
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - Jul 2010
Externally publishedYes


  • Galaxies: active
  • Galaxies: evolution
  • Galaxies: nuclei
  • Galaxies: starburst
  • Galaxies: stellar content

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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