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A Subarcsecond Near-infrared View of Massive Galaxies at z > 1 with Gemini Multi-conjugate Adaptive Optics

M. Lacy, H. U. Nørgaard-Nielsen, K. Nyland, M. Y. Mao, P. Jagannathan, J. Pforr, S. E. Ridgway, J. Afonso, D. Farrah, P. Guarnieri, E. A. GonzŠlez-Solares, M. Jarvis, C. Maraston, D. M. Nielsen, A. O. Petric, A. Sajina, J. A. Surace, M. Vaccari

We present images taken using the Gemini South Adaptive Optics Imager (GSAOI) with the Gemini Multi-conjugate Adaptive Optics System (GeMS) in three 2 arcmin2 fields in the Spitzer Extragalactic Representative Volume Survey. These GeMS/GSAOI observations are among the first ≈01 resolution data in the near-infrared spanning extragalactic fields exceeding 15 in size. We use these data to estimate galaxy sizes, obtaining results similar to those from studies with the Hubble Space Telescope, though we find a higher fraction of compact star-forming galaxies at z>2. To disentangle the star-forming galaxies from active galactic nuclei (AGNs), we use multiwavelength data from surveys in the optical and infrared, including far-infrared data from Herschel, as well as new radio continuum data from the Australia Telescope Compact Array and Very Large Array. We identify ultraluminous infrared galaxies (ULIRGs) at z~1-3, which consist of a combination of pure starburst galaxies and AGN/starburst composites. The ULIRGs show signs of recent merger activity, such as highly disturbed morphologies and include a rare candidate triple-AGN. We find that AGNs tend to reside in hosts with smaller scale sizes than purely star-forming galaxies of similar infrared luminosity. Our observations demonstrate the potential for MCAO to complement the deeper galaxy surveys to be made with the James Webb Space Telescope.

galaxies: evolution

The Astrophysical Journal
Volume 864, Number 1, Page 20
2018 August

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Instituto de Astrof√≠sica e Ci√™ncias do Espa√ßo Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia