Speaker
Description
Ram-pressure stripping (RPS) is an environmental process that transforms galaxies as they travel at high velocity through the hot gas in clusters and groups by removing their interstellar medium, forming one-sided tails. With radio continuum observations, we can detect the non-thermal component, i.e. the cosmic ray electrons and magnetic fields, in the stripped tails. Since the process of radiative aging causes the stripped tails to have steep radio spectra, observations at low radio frequencies are uniquely sensitive to them. Existing studies also tentatively suggest that RPS can steepen the spectral index of the galactic disk, potentially due to magnetic-field compression. In this poster we present the first systematic analysis of RPS galaxies at ultra-low radio frequencies (<100 MHz), using data from the LOFAR LBA Sky Survey (LoLSS). With an average noise level of 2 mJy/beam, LoLSS is the most sensitive survey in its frequency range (42-66 MHz) and covers the full sky north of δ=24°. Our sample consists of 112 RPS galaxies previously identified at 144 MHz in the LoTSS. This combined multi-frequency data set allows us to investigate the spectral properties of these systems in a statistical manner. We will present a statistical analysis of the integrated disk radio spectra, which allow us to probe for systematic magnetic field enhancement in RPS objects. Furthermore, we will show how we use the spectral gradients along the tails to constrain the kinematics of the stripping events.
| Talk category | NOVA Network 1 |
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