German ALMA Regional Centre (ARC) Node

The Atacama Large Millimeter/Submillimeter Array (ALMA) is a revolutionary interferometer for mm and submm astronomy in the Atacama desert in Northern Chile. It is operated by a global collaboration between Europe (ESO), North America (NRAO) and East Asia (NAOJ), in cooperation with Chile. The interface between ALMA and the user communities is provided by three ALMA Regional Centres (ARCs) in Europe, North America and East Asia.

The European ARC (EU ARC) is organized as a coordinated network with a central node at ESO Headquarters in Garching bei München and regional nodes located in Bologna(I), Bonn/Cologne(D), Grenoble(F), Leiden(NL), Manchester(GB), Ondrejov(CZ), and Onsala(S). The concept and the implementation of the EU ARC network has been described in an article in the ESO Messenger (Hatziminaoglou et al. 2015, Msngr. 162, 24).

The German ARC node is a collaboration of the universities of Bonn and Cologne. Its headquarters are located at the Argelander-Institut für Astronomie in Bonn. The German ARC node provides services to ALMA operations, the local astronomical community and the general public:

Newsletters and Announcements

Recent News

Upcoming I-TRAIN Session

[last update: 21 June 2021]

The European ARC Network has initiated I-TRAIN, a regular series of Interactive Training in Reduction and Analysis of INterferometric data. The sessions cover a wide range of topics of interest to the ALMA user community with the aim to help users gain expertise in working with interferometric data. The duration of each training session is usually about one hour, including a live demo and interactive Q & A.

Upcoming training session:
  • I-TRAIN #7: Polarization observations with ALMA on 24 June 2021, 11:00 CEST - instructions for preparing for the hands-on part are now available on the I-TRAIN homepage.
More details on this, past and future sessions, including the zoom link, can be found on the I-TRAIN homepage.

Update on operations at the German ARC node

[last update: 21 June 2021]

While the decreasing infection rates throughout Germany give hope for more face-to-face interaction in the coming months, the staff of the German ARC node continues to provide all services of an ARC node including user support and training by means of remote computing, emails and video-conferencing. Recent community events and user support include proposal preparation support in March/April via video tutorials, an online community meeting and one-on-one video chats as well as the ongoing hands-on training in radio interferometric data reduction, from the basic principles of radio interferometry to practical help with calibration and imaging of ALMA data (April to July).

While meeting in person is still discouraged, ALMA users are very welcome to contact the staff via email or via the helpdesk. Consultation and practical help via video conference systems can be arranged on short notice as well as access to the computing infrastructure for the efficient reduction and analysis of ALMA data.

Amplitude calibration issue affecting some ALMA data

[last update: 15 June 2021]

A visibility amplitude calibration error that affects fields containing strong astronomical emission has been discovered in ALMA interferometer observations up to and including Cycle 7. This calibration scaling error originates in the combined effect of correlator spectral normalization and Tsys calibration and affects both 12-m Array and Atacama Compact Array observations. The effect of this amplitude scaling error is most notable for observations of strong, relatively narrow spectral lines, typically related to Galactic ISM and Galactic star formation (e.g., molecular lines, masers, etc.). Full technical details of the issue can be found in this Knowledgebase article

In some cases this amplitude scaling error can exceed the nominal absolute flux calibration accuracy quoted in the ALMA Technical Handbook. Affected datasets that have not yet been delivered, will be processed with a renormalization correction to correctly scale the amplitude calibration before being sent to PIs. For affected data in the ALMA Archive, an investigation is underway and plans will be described in a future announcement.

We regret any inconvenience that may arise from this issue. If you have any questions, comments or concerns, please contact your local ALMA Regional Center via the ALMA Helpdesk at

ALMA Cycle 7 Science Observations Status Update

[last update: 31 May 2021]

While the full recovery of the arrays is still ongoing, ALMA has been used for PI science observations on a best-effort basis since 17 March 2021, when the 12-m Array started to conduct PI science observations with 37 antennas. PI science on the 7-m Array began on May 18 with initially eight antennas. The first set of antenna relocations was completed on May 10, moving the 12-m Array into the C43-6 configuration. Before the end of Cycle 7, it is planned to go through all remaining configurations (C43-7 to C43-10), although for a shorter duration than originally planned for each configuration.

The ALMA Regional Centers continue to provide support to all ALMA users. If you have any questions, comments or concerns related to your projects or the situation at ALMA, please contact your contact scientist, your ARC node or the ALMA Helpdesk in general.

Cycle 8 2021 Proposal Submission Statistics

[last update: 28 May 2021]

A detailed report of the Cycle 8 2021 Proposal Submission Statistics is now available as a pdf-document. The report provides a summary of items such as the number of submitted proposals and time requested, subscription rates, and comparisons with the number of hours requested in previous Cycles.

Hands-on Training Opportunity: ALMA Data Reduction

[last update: 16 April 2021]

The German ARC node offers hands-on training in the reduction and analysis of ALMA data in their online Master-level course Radio Interferometry 2021 in weekly zoom sessions in the months of April to July 2021.

Since 14 April 2021, the participants are guided through the various steps necessary to create fully calibrated data cubes from ALMA raw data. In the second part of the course, the participants learn how to construct image data cubes and maps from the calibrated data and how to analyze the data. The hands-on work is complemented by overview talks on the basic concepts of radio interferometry and on various special cases of radio interferometric data.

Thanks to its extensive online material, it is still possible to join the course. Interested students and colleagues are encouraged to contact the course coordinator.

New ALMA Science Archive remote visualization tool

[24 March 2021]

CARTA, the Cube Analysis and Rendering Tool for Astronomy, has been integrated into the ALMA Science Archive (ASA). Now all 500,000+ ALMA science FITS files in the ALMA archive can be previewed using CARTA (excluding Cycle 0). CARTA is a new image visualization and analysis tool that can visualize large images from a remote server within seconds. More details can be found here or on the CARTA hopepage.

EU-ARC Virtual Community Assembly on 19 March 2021

[15 March 2021]

The European ALMA Regional Centre invites all European ALMA users to a virtual community assembly on 19 March at 12:30 CET. At this community meeting, we will update you on the current and upcoming observing cycle and address FAQs on how PI science will be carried out. Also we can answer any questions you may have on your ALMA projects and support from the European ARC network. The meeting can be accessed at this link.