The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3

Fu, Hai; Cooray, Asantha; Feruglio, C.; Ivison, R. J.; Riechers, D. A.; Gurwell, M.; Bussmann, R. S.; Harris, A. I.; Altieri, B.; Aussel, H.; Baker, A. J.; Bock, J.; Boylan-Kolchin, M.; Bridge, C.; Calanog, J. A.; Casey, C. M.; Cava, A.; Chapman, S. C.; Clements, D. L.; Conley, A.; Cox, P.; Farrah, D.; Frayer, D.; Hopwood, R.; Jia, J.; Magdis, G.; Marsden, G.; Martínez-Navajas, P.; Negrello, M.; Neri, R.; Oliver, S. J.; Omont, A.; Page, M. J.; Pérez-Fournon, I.; Schulz, B.; Scott, D.; Smith, A.; Vaccari, M.; Valtchanov, I.; Vieira, J. D.; Viero, M.; Wang, L.; Wardlow, J. L.; Zemcov, M.
Bibliographical reference

Nature, Volume 498, Issue 7454, pp. 338-341 (2013).

Advertised on:
6
2013
Journal
Number of authors
44
IAC number of authors
2
Citations
124
Refereed citations
120
Description
Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5×1010 solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies that already have stellar masses above 2×1011 solar masses at z~2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at z = 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4×1011 solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by z~1.5.
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Formation and Evolution of Galaxies: Observations in Infrared and other Wavelengths
This IAC research group carries out several extragalactic projects in different spectral ranges, using space as well as ground-based telescopes, to study the cosmological evolution of galaxies and the origin of nuclear activity in active galaxies. The group is a member of the international consortium which built the SPIRE instrument for the
Ismael
Pérez Fournon