ESO - EU ARC Newsletter August 2024

Welcome to the European ALMA Regional Centre Newsletter!

This monthly newsletter is a compilation of recent European ALMA Regional Centre news and announcements, showcasing an exciting ALMA science result by European colleagues. Every month, you can learn an interesting ALMA fact in "Did you know" and give your opinion about a particular ALMA matter in the "Poll of the month".

European ARC News and Announcements

	Video on ALMA's Wideband Sensitivity Upgrade released 28 Aug 2024: In June 2024, the ESO workshop "The Promises and Challenges of the ALMA Wideband Sensitivity Upgrade" was held in Garching to introduce all details of this ambitious upgrade project to the user community (see the announcement in July's newsletter). Following this and in an effort to further advertise this upgrade to the community and the public in general, ESO has just released the video "ALMA's extreme makeover: the Wideband Sensitivity Upgrade". You can watch the video here. Contributed by Maria Diaz Trigo.
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	First Joint VLT/ALMA Observing Proposal successfully completed 12 Aug 2024: From Cycle 10, it has been possible to propose for joint VLT and ALMA observations. The first joint VLT/ALMA observing proposal has now been completed (prog ID 113.269Z, PI Benisty). Multi-epoch observations of a protoplanetary disc using VLT/SPHERE and ALMA revealed the suface and midplane layers of the disc. These observations aim to understand the mechanisms and timescale of cooling, which are critical to understanding disc evolution.
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ALMA science highlight

ALESS-JWST: Joint (sub-)kiloparsec JWST and ALMA imaging of z ~ 3 submillimeter galaxies reveals heavily obscured bulge formation events

JWST NIRCam and ALMA 350 GHz imaging for 3 of 13 submillimetre galaxies in Hodge et al. (2024). For each source, the columns show the NIRCam RGB image (constructed from F444W, F356W, and F200W; left), the ALMA 350 GHz image (middle), and the ALMA contours in red overlaid on the RGB image (right).

Submillimetre galaxies have the highest star formation rates in the Universe. These galaxies are thought to be the progenitors of present-day massive elliptical galaxies. Before JWST, it was extremely difficult to characterise the stellar distributions of submillimetre galaxies because they were so heavily dust-obscured.
Recent work by Hodge et al. (2024) combined JWST and ALMA imaging to examine the stellar emission and obscured star formation in 13 submillimetre-selected galaxies. They found their stellar structure to be similar but more extended than ALMA imaging of their obscured star formation, as well as evidence for mergers and interactions. Hodge et al. conclude that we are witnessing ongoing heavily obscured and interaction-induced bulge formation in these galaxies.

Contributed by Hannah Stacey

ALMA poll of the month

Lower receiver temperatures

Larger bandwidth (x4)

High spectral resolution (10 m/s)

Not having to sacrifice bandwidth for spectral resolution

The WSU will have no impact on my science

Results from July's poll, "Which ALMA antenna is your favourite?"

Group photo of the UK node

Did you know?

We need to re-measure and correct 'antenna positions' regularly at ALMA due to the active changing and moving of antennas within ALMA's dynamic array as we change configurations. Often, positions can be seen to change by more than 1mm. However, this should not be misinterpreted as the antennas physically moving, which was incorrectly stated in last month's newsletter. Long-lived (week timescale) atmospheric trends affect path delays and ultimately 'locate' the antenna at a slightly different position. We use the positions measured closest in time to when data were taken to do the best possible calibration of ALMA observations.

If you would like to contribute an ALMA science highlight, please contact the newsletter editor at Hannah.Stacey@eso.org.