Speaker
Description
The spectra of high-redshift (z ~ 6) quasars reveal numerous metal absorption lines, yet it remains unclear how early galaxies transported heavy elements from compact star-forming regions into their large-scale (~100 kpc) gaseous environments. What are the origins of these early metals? How did they reach their observed locations? And what role did they play in cosmic reionization?
In this talk, I will present our recent results of early metal host galaxies using ALMA searches for [C II] 158 μm emission. A pilot observation detects the host galaxy of an [O I] absorber at z = 5.978. Follow-up observations indicate that bright [C II] emitters as absorber hosts are rare, pointing to more complex galaxy properties than predicted by current models. The detected host resides in a dark matter halo of about 4 × 10¹¹ solar masses—more massive than typical simulation predictions—highlighting the potential importance of massive galaxies in early metal enrichment. In addition, possible [C II] emitters at distances greater than 50 kpc suggest that metals can be transported via strong galactic winds. I will also discuss possible environmental effects. JWST/NIRCam wide-field slitless spectroscopy (WFSS) observations systematically examine absorber hosts and their surroundings, with a pilot study identifying a Mg II absorber at z = 5.428 within a galaxy overdensity, suggesting a preference for protocluster environments. Finally, I will outline future directions for circumgalactic medium studies in the JWST era, and share what our results imply for upcoming observations.
| Session Selection | Astronomy and Astrophysics |
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