24–28 Jun 2024
Swedish Royal Academy of Sciences
Europe/Stockholm timezone

The Resolved Dust and Interstellar Medium of a z=7.31 Rotating Disk

27 Jun 2024, 12:15
15m
Beijer auditorium (Swedish Royal Academy of Sciences)

Beijer auditorium

Swedish Royal Academy of Sciences

Speaker

Hiddo Algera (Hiroshima University)

Description

Over the last decade, ALMA has revolutionized our understanding of the interstellar medium (ISM) conditions of distant galaxies. For one, ALMA has now detected (sub-)millimeter continuum emission from dozens of galaxies at $z > 6.5$, establishing the importance of dust-obscured star formation already within the first 800 Myr after the Big Bang. Moreover, through various bright emission line diagnostics such as [CII]$_{158}$ and [OIII]$_{88}$, ALMA can be used to directly study the physical conditions and kinematics of the ISM within the earliest galaxies. In this talk, I will first present new ALMA continuum observations of a dusty galaxy at $z=7.31$ in six unique bands (including Band 9) which meticulously constrain its dust SED and demonstrate it to host a massive dust reservoir. Producing such a large dust mass so shortly after the Big Bang likely requires efficient grain growth in a dense ISM, on top of efficient dust production from supernovae. This suggests the galaxy to be a rather evolved system already by $z > 7$, which is supported by recent high-resolution ($\sim0.2''$) [CII] observations demonstrating it to be a rotating disk — the most distant cold disk known to date. I will present matched-resolution Band 8 dust continuum and [OIII] observations of this spectacular galaxy, and discuss its multi-band kinematics, star formation and ISM properties at high spatial resolution.

Primary author

Hiddo Algera (Hiroshima University)

Presentation materials