How do high redshift galaxies sustain higher star formation rates?
| Main Author: | Piyush Sharda |
|---|---|
| Format: | info Proceeding |
| Terbitan: |
, 2020
|
| Online Access: |
https://zenodo.org/record/3756472 |
Daftar Isi:
- We carry out the first tests of star formation on multiple star forming regions in two high redshift starburst galaxies - SDP 81 (lensed, z~3.0) and AzTEC1 (non-lensed, z~4.3). Using high-resolution (sub-kiloparsec scale) archival ALMA data, we analyze the star formation rate (SFR), gas content and kinematics in the nuclei of both the galaxies, as well as in an off-center star forming clump in AzTEC1, all of which show sufficient resolution to carry out the analyses. The SFR surface density we find in these regions is of the order of a few 100 Msun per yr per kpc^2 and the Mach numbers range between 30 to 100, higher than those for starburst galaxies at low redshift. Our measurements allow us to compare the SFRs from various star formation models with those observed, revealing that the role of turbulence is crucial to explaining the observed SFRs. While the Kennicutt Schmidt (KS) relation underestimates the SFR in these regions, the single-freefall model by Krumholz, Dekel and McKee (KDM) gives good predictions of SFR in regions with low Mach numbers. The multi-freefall (turbulence) model by Salim, Federrath and Kewley (SFK) gives reasonable predictions of the SFR in all the regions. Our analysis reveals that an interplay between gravity and turbulence and can help sustain high SFRs in these starbursts just a Gyr after Big Bang. This analysis is easily reproducible and opens an exciting window for studying resolved star formation characteristics in the early Universe.