Welcome to the European ALMA Regional Centre Newsletter!
This Newsletter is a compilation of recent European ALMA Regional Centre Announcement items. Follow the links or visit the European ARC Announcements to read more. In addition to these Announcements the Newsletter informs you about various developments in the ALMA Programme, as well as about ALMA or ALMA-related meetings.
The ALMA Director, on behalf of the Joint ALMA Observatory (JAO) and the partner organizations in East Asia, Europe, and North America, is pleased to announce the ALMA Cycle 5 Call for Proposals (CfP) for scientific observations to be scheduled from October 2017 to September 2018. The deadline is 20 April 2017, 15:00 UT.
ALMA Cycle 4 (1 Oct 2016 – 30 Sept 2017) continues and PI observations will resume on 1 March 2017 after the "austral winter" engineering period through February. More information on the ALMA Status page.
Announcement from the German Node
The course Radio Interferometry: Methods and Science is organized by the German ARC node and offers a hands-on overview of major aspects of radio/mm/submm interferometry for master students, PhD students and senior astronomers.
It is expected that phased ALMA will participate in some GMVA observations (GMVA) during ALMA Cycle 5 (Oct 1 2017 - Sept 30 2018; see the ALMA Cycle 5 Pre-announcement). Any GMVA proposal requesting phased ALMA during Cycle 5 must be submitted by the 1 February 2017 deadline; see the proposal call.
The latest release of ALMA Science Verification (SV) data will contain observations of the Sun obtained during the Solar commissioning campaigns in 2014 and 2015. The release contains mosaics and single pointing observations in quiet and active solar regions at Band 3 and 6 with the 12-metre, 7-metre and total power arrays. The data are available under ALMA Science Portal SV.
Starting this year, funding will be available again for travel to one of the European ALMA Regional Centre nodes in Europe, for ALMA users who need face-to-face support for their ALMA projects. Users wishing to apply for MARCUs funding should fill out the form in addition to submitting a Helpdesk ticket that is required to arrange the ARC node visit. Face-to-face visits to ARC nodes can be arranged for assistance with data reduction, proposal preparation, and archive research projects.
Getting Ready for ALMA Band 5 - Synergy with APEX/SEPIA
ESO Garching, February 1-3, 2017
Following on the successes of the ALMA Band 5 science verification and Band 5 Swedish-ESO PI receiver at APEX (SEPIA) programmes (see Humphreys et. al 2017 and Immer et al. 2016, respectively), a workshop — Getting Ready for ALMA Band 5 - Synergy with APEX/SEPIA — was held at ESO Headquarters in Garching from February 1st to 3rd, 2017.
The conference will be described in more detail in De Breuck et al. 2017, and the presentations are available online here: https://www.eso.org/sci/meetings/2017/band5.html. This workshop had over 50 participants representing all the ALMA regions, and highlighted results with and predictions for the highly-anticipated Band 5, which spans 163-211 GHz on ALMA (and 157-211 GHz on APEX). This band will be offered beginning with Cycle 5 (proposals due in April), with Band 5 science observations starting March 2018 (i.e. mid-Cycle 5). Band 5 will add to ALMA to capability to perform sensitive measurements of the 183.3 GHz water maser line in the local Universe, in addition to many other molecular and atomic transitions at local and high redshifts.
Humphreys et al. 2017 will be in Messenger 167, March 2017
De Breuck et al. 2017 will be in Messenger 167, March 2017
Group photo of the attendees of the "Getting Ready for ALMA Band 5" conference (ESO Headquarters).
Group photo of the ACA Total Power Spectrometer PDR attendants in Daejeon (South Korea).
ACA Total Power Spectrometer PDR
On February 20 and 21, the Preliminary Design Review (PDR) for the ACA Total Power Spectrometer was held at KASI in South Korea.
Over the past years KASI, the Korea Astronomy and Space Science Institute in Daejeon, and NAOJ have been collaborating on a plan to build a dedicated spectrometer for the Total Power (TP) array. KASI proposed two possible spectrometer concepts: one based on FPGA (Field-Programmable Gate Arrays) technology, and the other one based on the GPU (Graphics Processing Unit) technology. Since the performance of the GPU technology has been and will be continuously improved by large communities of computer games and supercomputing, the GPU technology is quite promising for the future spectrometers and correlators.
NAOJ and KASI have therefore decided to develop a GPU-based spectrometer for the TP Array. An important design concept of the spectrometer based on GPU technology is to not change any components of the ACA correlator but to add a few new components that operate in parallel to and independent of the ACA correlator.
Following the preliminary design phase and presentations of the concept to various ALMA bodies and at workshops in 2015 and 2016, the PDR was held on 20/21 February 2017 in Daejeon (South Korea) with a panel of international experts and observers, chaired by the JAO Observatory System Engineer.
The panel were impressed by the hard work done by the TPS team and congratulated them on the excellent preparation for this review. The design was found to be very well developed and the documentation was in a generally good state. The panel found no blocking issues with the preliminary design and appreciated the potential benefits of the use of commercial of-the-shelf technology in this design. The panel outlined a few action items which will require further work and which will need to be closed out to conclude the PDR - none of these present any significant development risk. The final PDR report is being prepared.
ESO Technology Development Programme supports future ALMA Upgrades
Low Noise Amplifiers (LNA) based on hetero-junction, III-V compound semiconductors have been around for more than 35 years and contributed to substantial improvements in radio telescope performance since their introduction. Despite the fact that this technology has been around for a relatively long time considering how quickly technology evolves, a steady improvement in terms of lower noise and higher operating frequency can still be observed. Recent examples are e.g. the development of cryogenic LNAs covering both ALMA Band 2 and 3, 67 – 116 GHz, by academic organizations [1] as well as industry [2]. But also for room temperature LNAs significant progress for radio astronomy applications is reported [3].
In the framework of future upgrades to the signal chain of the ALMA instrument this steady progress in the areas of, cryogenic, LNAs and HEMT devices resulting in better noise performance and increased bandwidth is of much interest. However in planning these upgrades questions arose how much more improvement can be expected and where this technology can be most beneficial for ALMA. In assessing these upgrade opportunities two specific questions related to LNA performance that play an important role in making future decisions in ALMA upgrades were identified:
What is the best trade-off in terms of instrument sensitivity for the instantaneous bandwidth versus receiver noise temperature? E.g. a wider intermediate frequency (IF) bandwidth goes at the expense of an increase of the LNA noise contribution. So is it beneficial to increase the IF bandwidth beyond e.g. 16 GHz or is it better to stay with a reduced bandwidth and have a lower noise contribution from the LNA?
How far can cryo LNAs based on HEMT technology be pushed in replacing SIS mixers? The most recent development results indicate that it is plausible that up to 116 GHz (ALMA Band 3 top edge) cryogenic LNAs can provide comparable performance to SIS mixers at an increased RF bandwidth covering both ALMA Bands 2 and 3. Based on this progress it might be feasible that in the future cryo LNA technology can replace SIS mixers in ALMA Bands 4 and 5.
To address these questions an ESO internal research project was defined. The key objectives of this project are:
To demonstrate the performance of HEMT devices from the most advanced foundry processes in prototype cryogenic amplifiers at both sub-mm wavelengths and ALMA intermediate frequencies;
Increase the technology readiness level (TRL) of cryogenic sub-mm and very wideband IF LNAs to at least 5 (ESO scale [4]);
Establish test facilities to accurately characterize the performance of these cryogenic amplifiers;
Analyse the test results obtained and provide recommendations to support system trade-offs for future ALMA upgrades. It is foreseen that in particular recommendations will be given on:
noise performance vs. RF and IF bandwidth and
highest frequency of operation where cryogenic HEMT LNAs can outperform current SIS mixer technology.
In June 2016 the project proposal was submitted under the ESO Technology Development Programme [5] and recently selected for funding. The project will be led by EASC staff. The work programme itself will be accomplished through a collaboration between EASC and organizations, both academic and commercial, which have demonstrated expert knowledge and experience in the field of cryogenic, low noise amplifiers.
We are very grateful to the Technology Development Advisory Team under the leadership of Mark Casali for supporting this ALMA development and are confident that this project will have an important impact in making essential decisions in future choices for the telescope upgrades.
References
[1]
D. Cuadrado-Calle and et al, "Broadband MMIC LNAs for ALMA Band 2+3 With Noise Temperature Below 28 K," IEEE Transactions on Microwave Theory and Techniques, no. 99, 2017.
J. Schleeh, N. Wadefalk, P. Å. Nilsson and J. Grahn, "10 K Room Temperature LNA for SKA Band 1," in Microwave Symposium (IMS), 2016 IEEE MTT-S International, San Francisco, 2016.
[4]
M. Casali, "ESO Technology Readiness Levels / ESO-232765," European Southern Observatory, 2014.
[5]
"Technology Development," European Southern Observatory, [Online]. Available: http://www.eso.org/intra/programmes/technology.html.
Upcoming ALMA or ALMA-related Meetings
ALMA Proposal Preparation Days 2017
To prepare the local astronomical community for the Cycle 5 proposal deadline of 20 April 2017, the following "ALMA Proposal Preparation Days" are organised:
The European Week of Astronomy and Space Science (EWASS) Special Session No. 20, held on the first day (26 June) of the conference, will be devoted to the three particular modes of observing with ALMA that demonstrate the unique capabilities of the facility: High-Frequency Observations (specifically in Bands 8, 9 and 10); High-Angular-Resolution Observations with baslines up to 16 km; Solar Observations. Further details on the SS20 site.
The scope of this three day workshop is to (1) review the high-resolution ALMA science results obtained to date, (2) identify detailed science cases for the future baseline expansion of ALMA (e.g. aiming at an angular resolution of ~ 0.001”-0.003"), (3) discuss the scientific and technical requirements such as, for example, angular resolution, number and size of the antennas, sensitivity and operational frequency, and (4) review the technical feasibility studies for longer baseline imaging. We envision the output of this workshop to be used as a guideline to pave the pathway for the future expansion of ALMA.
