Cospatial star formation and supermassive black hole growth in z ∼ 3 galaxies: Evidence for in-situ co-evolution

W. Rujopakarn, K. Nyland, G. H. Rieke, G. Barro, D. Elbaz, R. J. Ivison, P. Jagannathan, J. D. Silverman, V. Smolčić, T. Wang

Research output: Contribution to journalArticlepeer-review


We present a sub-kpc localization of the sites of supermassive black hole (SMBH) growth in three active galactic nuclei (AGN) at z ∼ 3 in relation to the regions of intense star formation in their hosts. These AGNs are selected from Karl G. Jansky Very Large Array (VLA) and Atacama Large Mil- limeter/submillimeter Array (ALMA) observations in the HUDF and COSMOS, with the centimetric radio emission tracing both star formation and AGN, and the sub/millimeter emission by dust tracing nearly pure star formation. We require radio emission to be > 5× more luminous than the level asso- ciated with the sub/millimeter star formation to ensure that the radio emission is AGN-dominated, thereby allowing localization of the AGN and star formation independently. In all three galaxies, the AGN are located within the compact regions of gas-rich, heavily obscured, intense nuclear star formation, with Re= 0.4 - 1.1 kpc and average star formation rates of ≃ 100 - 1200 M⊙yr-1. If the current episode of star formation continues at such a rate over the stellar mass doubling time of their hosts, ≃ 0.2 Gyr, the newly formed stellar mass will be of the order of 1011M⊙ within the central kpc region, concurrently and cospatially with significant growth of the SMBH. This is consistent with a picture of in-situ galactic bulge and SMBH formation. This work demonstrates the unique comple- mentarity of VLA and ALMA observations to unambiguously pinpoint the locations of AGN and star formation down to ≃ 30 mas, corresponding to ≃ 230 pc at z = 3.

Original languageEnglish (US)
JournalUnknown Journal
StatePublished - Jan 22 2018


  • Galaxies:evolution
  • Galaxies:star formation

ASJC Scopus subject areas

  • General

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