20–27 Mar 2026
Wild View Resorts
Africa/Gaborone timezone

The Puzzling Properties of a 260-kpc HI Disk Hidden Behind the Galactic Plane

24 Mar 2026, 15:15
15m
Wild View Resorts

Wild View Resorts

Plot 80 President Avenue, Kasane, Botswana
Online - Talk 3&4 Galaxies Science & Engineering

Speaker

Renée C. Kraan-Korteweg (University of Cape Town)

Description

We present deep MeerKAT follow-up observations (16 hrs with the 32k correlator) of an extraordinary, extremely low column-density HI disk uncovered in the SARAO MeerKAT Galactic Plane Survey (SMGPS). MeerKAT reveals a vast, patchy, spiral-like structure dominated by exceptionally low column densities (10^18 – 10^20/cm^2). Despite its modest HI mass, the disk reaches an astonishing ~260 kpc—larger than Malin 1—and lies far off the established HI mass–diameter relation. The galaxy sits directly on the Galactic equator at ℓ = 325°, buried behind ~57 mag of extinction, rendering its HI disk the only observable component. The velocity field and enhanced outer dispersions point to past disturbance or large-scale gas redistribution. In this talk, we present the multi-scale morphology and kinematics from MeerKAT and explore possible formation pathways for this remarkable and puzzling low-mass HI giant.

Stream Science or Engineering

Primary authors

Renée C. Kraan-Korteweg (University of Cape Town) Prof. DJ Pisano (University of Cape Town)

Presentation materials

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