Colloquium: Full of Orions? Pushing the resolution and bandwidth limits in studies of high-z dusty galaxies.

© CC-BY-SA-NC (Credit: ALMA / M. Rybak / ESO/IDA/Danish 1.5 m/R.Gendler, J.-E. Ovaldsen, and A. Hornstrup; or ALMA / M. Rybak / ESO)

Will a newborn star feel a difference between being born in Orion today and in a massive, dusty galaxy 10 billion years ago? Forming stars at rates 100x higher than any present-day galaxy, the dust-enshrouded, sub-mm bright galaxies play a key role in the early Universe.

Unfortunately, our understanding of physical conditions in dusty galaxies has been very limited: both due to the coarse resolution of mm-wave observatories and the lack of robust spectroscopic redshifts. Thankfully, the ongoing revolution in angular resolution and bandwidth of mm-wave facilities is transforming our understanding of high-z dusty galaxies.

I will present recent ALMA observations of (probably) the best-studied SMG: SDP.81, a spectacular, strongly gravitationally lensed starburst. With ∼40 hours of ALMA long-baseline, multi-band observations, we mapped the physical conditions in this SMG at an unprecedented, ∼100 pc resolution - directly comparable to nearby galaxies.

Finally, I will discuss how the upcoming ultra-wideband spectroscopy - e.g., with the Delft/Leiden-developed DESHIMA spectrometer - is paving the way for large-scale redshift surveys at mm-wavelengths.