70h on ALMA to study the inter-stellar medium of young galaxies with ALPINE

October 6, 2017

Galaxies in the early Universe (< 2 billion years after the Big Bang or <10% of the current age of the Universe) experience a rapid growth in stellar mass. This goes along with a rapid evolution and transformation of their inter-stellar medium (ISM) properties and physical structure. The mechanisms and physics that lead to this short early growth phase are mostly unknown.

We got 70h on the Atacama Large (Sub-) Millimeter Array (ALMA) to study the gas and dust properties of young galaxies during this early growth phase to address these questions. Our ALMA Large Program to investigate CII at early times (ALPINE) will observe these galaxies at a rest-frame wavelength of 158 micro-meter and will measure their singly ionized Carbon emission (C+) as well as their far-infrared (FIR) continuum.

ALPINE will measure C+ and FIR continuum emission for a sample of 122 main sequence star-forming galaxies that are spectroscopically confirmed to be at redshifts 4 < z < 6 in COSMOS as well as the ECDFS. Importantly, these galaxies are representative of the Universe at these times and will therefore also provide a representative picture of their physical properties. Furthermore, the galaxies span a wide range in stellar masses (109-1010 solar masses) and star formation rates (10-500 solar masses per year).

These are the main science questions that will be addressed with ALPINE:

  • What are the mechanisms that fuel the initial growth of galaxies? - ALPINE will give accurate measurements of the gas properties and gas fractions of galaxies at z > 4.
  • What are the ISM properties of galaxies in the early Universe and how do they compare to the present day galaxies? - ALPINE will accurately constrain the dust properties of these galaxies.

In addition to this, ALPINE will provide a lasting legacy in data-rich ECDFS and COSMOS areas. These data will pave the way for detailed follow-up observations, e.g., with ALMA at higher spatial resolution, and provide a reference sample for studies with future facilities like JWST.

Questions? - direct them to A. Faisst (North America PI) at afaisst[at]ipac.caltech.edu