HIandMIGHTEE: From gas to galaxies with the MIGHTEE survey

One of the key elements in the formation and evolution of galaxies is the exchange of gas between the space between the stars within galaxies, their surrounding gaseous environment and the larger-scale filamentary structure in which galaxies are largely embedded.

The atomic hydrogen component of this gas, which is the building block of all the objects we see in the Universe, can be traced using an emission line which is found at 21cm in the radio waveband. However, this is a very weak emission line and the vast majority of previous studies have been restricted to the very local Universe.

In this project we will, for the first time, be able to detect and measure where this atomic hydrogen exists, covering a time range of around half the age of the Universe. We can therefore understand how where this gas resides has evolved over the past 6 billion years, providing much needed information on how gas cools and condenses to form the stars and galaxies we see in the Universe today.

One of the novel approaches we will undertake is to use the wealth of data at other wavelengths in order to paint a complete picture of galaxy evolution, but also to be able to dig deep into the noisy data which contains the atomic hydrogen signal. We can do this as we know the position at distance of the galaxy from other data, which allows us to then extract the signal from the right place in the radio data in order to obtain a measurement of the atomic hydrogen line, regardless of whether it is detected or not. The by combining all these data we can reconstruct how much atomic hydrogen there is using advanced statistical methods.