Figure 1: Absorption profile of the two water transitions observed towards the far-infrared continuum emission of the distant starburst galaxy (SPT 0346-52).
Figure 2. Molecular outflow rate (Ṁ) as a function of star formation rate (SFR) for galaxies with detected molecular outflows. Outflows driven by AGNs are shown by diamonds, while those driven by starbursts are shown by star symbols. Each object is coloured according to its redshift. The range and average of best-fit outflow rates of our object (SPT 0346-52) are shown. The molecular outflow detected in this work is in the most powerful starburst. Additional data include both low-redshift (z~1.5-5.3) sources. A representative uncertainty for all low-redshift sources (±0.3 dex) is shown for one such source.
Using the Atacama Large Millimeter/submillimeter Array, a team led
by scientists from the Kavli Institute have observed two water
absorption lines towards a starburst galaxy (i.e., forming stars at a
rate ~4000x faster than the Milky Way) in the early Universe, or about
one billion years after the Big Bang, finding evidence for outflowing
gas (Figure 1).
The distinct shape of these blueshifted water lines, in addition to
the extremely hot and dense environments required for their
detection, indicates that they originate from a massive nuclear outflow.
When the outflow rate and star formation rate of this object
are compared to those of local galaxies and other high-redshift objects
(see Figure 2), it is apparent that the outflow detected here is at the
highest redshift and originates from the object with the highest star
formation rate. However, the outflow rate is much less than the star
formation rate, suggesting that this outflow does not represent a
dominant form of mass loss in this system. Thus, the galaxy is likely
undergoing a period of runaway star formation.
This work was led by Gareth Jones, a postdoctoral research associate
at the Kavli Institute and the results has been published in Astronomy
& Astrophysics Letters:
- Online paper: https://www.aanda.org/articles/aa/abs/2019/12/aa36989-19/aa36989-19.html
- arxiv link: https://arxiv.org/abs/1911.09967
