Carbonaceous dust grains within galaxies seen in the first billion years of cosmic time

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• Joris Witstok
• Wednesday 01 March 2023, 13:40-14:05
• The Hoyle Lecture Theatre + Zoom .

If you have a question about this talk, please contact Hannah Uebler.

Interstellar dust captures a significant fraction of elements heavier than helium in the solid state and is an indispensable component both in theory and observations of galaxy evolution. Dust emission is generally the primary coolant of the interstellar medium (ISM) and facilitates the gravitational collapse and fragmentation of gas clouds from which stars form, while altering the emission spectrum of galaxies from ultraviolet (UV) to far-infrared wavelengths through the reprocessing of starlight. However, the astrophysical origin of various types of dust grains remains an open question, especially in the early Universe. I will present direct evidence for the presence of carbonaceous grains from the detection of the broad UV absorption feature around 2175 Å in deep near-infrared spectra of galaxies up to the first billion years of cosmic time, at a redshift (z) of ~7. This dust attenuation feature has previously only been observed spectroscopically in older, more evolved galaxies at redshifts of z < 3. The carbonaceous grains giving rise to this feature are often thought to be produced on timescales of hundreds of millions of years by asymptotic giant branch (AGB) stars. These results suggest a more rapid production scenario, likely in supernova (SN) ejecta.

This talk is part of the Institute of Astronomy Seminars series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology lists
• Cosmology, Astrophysics and General Relativity
• Institute of Astronomy Seminars
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• Priscilla
• The Hoyle Lecture Theatre + Zoom

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