Speaker
Description
Recent JWST observations have revealed that extreme emission line galaxies (EELGs) are ubiquitous in the early universe. The extreme emission feature is linked to the rising star formation history, but it’s unclear if direct gas accretion or mergers are driving the burst of star formation. In this talk, I will discuss properties of EELGs at $2.5<z<4$ and how they can inform our understanding of galaxies in the early universe. Through deep NIRCam imaging from the JADES, we find that EELGs at z~3 are more likely to experience strong interactions compared to control samples, even after matching in terms of both stellar mass and specific star formation rates. This work proves that gas cooling induced by strong interactions and/or major mergers could be triggering the starburst and might be responsible for the over-abundance of EELGs in the early universe.
I will also discuss a unique Lyman-continuum (LyC) emitter among our EELGs. The galaxy is at z=3.088 and has a 4-sigma detection in the F336W/UVIS filter, which cleanly samples the rest-wavelength between 760-900 Å. Interestingly, the LyC emission is spatially offset by 0.29’’+/-0.04 (2.2 +/- 0.3 kpc) from the non-ionizing rest-UV emission peak (F606W). The galaxy has a deep NIRSpec spectrum from the JADES showing multiple emission lines including the [SIII] 9069, 9531 doublet, which gives us a metallicity and pressure independent ionisation parameter. We believe the ionising photons are leaking through a narrow ionisation cone of optically thin interstellar medium that could have been created by a past merger event. We have developed a simple model to estimate the opening angle of the ionisation cone. I will discuss the implications of our model on the general population of LyC leakers at higher redshifts.