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ACES

ALMA Central Molecular Zone Exploration Survey

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Project Summary

ACES is an ALMA Band 3 survey designed to map the entire Central Molecular Zone (CMZ; inner few hundred parsecs of the Galaxy), covering all material above a hydrogen column-density threshold of 1022 cm2 in a contiguous mosaic using all 3 ALMA arrays. This full mosaic is composed of 45 individual sub-mosaics, which are combined to yield the full coverage.  The survey achieves an angular resolution ~ 1.5 - 2.5” and a spectral resolution between 0.2 - 3 km/s. The spectral setup is tuned to observe the 3mm continuum emission, along with optimal tracers of the physical, chemical, and kinematic conditions in over 70 spectral features (e.g. HCO+, HNCO, SiO, H40ɑ, complex organic molecules) of the gas in the CMZ.

ACES is dedicated to understanding the mass flows and energy cycles within the inner regions of the Galaxy, providing a multiscale view of the properties of all potentially star-forming Galactic Centre gas, from global scales (100 pc) down to dense 0.05 pc structures that are expected to host individual star‑forming cores, down to sub-sonic (<0.4 km/s) velocity resolution. 

Obtaining the Data

The ACES data release can be obtained here: https://almascience.eso.org/almadata/lp/ACES/

There are 91 packages in total:

  • 1 group-level package containing all full CMZ mosaic products, along with array-combined cubes for each of the 45 ACES sub-mosaics.
  • 45 member-level packages containing continuum and cube products from the 12m data.
  • 45 member-level packages containing cube products from the 7m data.

The first release of the ACES data includes:

  • For the full CMZ mosaics
    • 3mm continuum images
    • Spectral line products for a suite of key detected lines, including:
      • Image cubes
      • Integrated intensity maps
      • Peak intensity maps
      • Position-velocity maps
      • Velocity maps
      • Noise maps
  • For the 45 individual sub-mosaics
    • 3mm continuum images
    • 12m7mTP cubes for all spectral windows
    • 12m cubes for all spectral windows
    • 7m cubes for all spectral windows

For a detailed overview of the data release, please refer to the data release document, as well as the README files for each package.

ACES Team Members

Steven N. Longmore, John Bally, Ashley T. Barnes, Cara Battersby, Laura Colzi, Adam Ginsburg, Jonathan D. Henshaw, Paul T. P. Ho, Izaskun Jiménez-Serra, J. M. Diederik Kruijssen, Elisabeth A.C. Mills, Maya A. Petkova, Mattia C. Sormani, Robin G. Tress, Daniel L. Walker, Jennifer Wallace, Emad Alkhuja, Lucia Armillotta, Nazar Budaiev, Rojita Buddhacharya, Alyssa Bulatek, Michael Burton, Natalie O. Butterfield, Laura A. Busch, Paola Caselli, Mélanie Chevance, Claire Cook, Samuel Crowe, Ana Karla Díaz-Rodríguez, Enrico DiTeodoro, Simon R. Dicker, Katarzyna M. Dutkowska, Adam Fairley, Christoph Federrath, Rubén Fedriani, Zi-Xuan Feng, Karl Fiteni, Gary Fuller, Pablo García, Javier Goicoechea, Philipp Girichidis, Simon C. O. Glover, Mark Gorski, Savannah R. Gramze, Qi-Lao Gu, H. Perry Hatchfield, Christian Henkel, Rebecca J. Houghton, Pei-Ying Hsieh, Yue Hu, Katharina Immer, Desmond Jeff, Janik Karoly, Jens Kauffmann, Ralf S. Klessen, Mark R. Krumholz, Alex Lazarian, Emily M. Levesque, Fu-Heng Liang, Dani Lipman, Xunchuan Liu, Xing Lu, Qiu-yi Luo, Alessandro Lupi, Laura McCafferty, S. Martín, Farideh Mazoochi, Mark R. Morris, Marie Nonhebel, Francisco Nogueras-Lara, Tomoharu Oka, Juergen Ott, Marco Padovani, Xing Pan, Jaime E. Pineda, Thushara G. S. Pillai, Marc W. Pound, Miguel Requena Torres, Denise Riquelme-Vásquez, Víctor M. Rivilla, Galaxy Salo, Álvaro Sánchez-Monge, Miriam G. Santa-Maria, Rainer Schoedel, Anika Schmiedeke, Matthias Schultheis, Howard A. Smith, Yoshiaki Sofue, Leonardo Testi, Grant R. Tremblay, Arianna Vasini, Gijs Vermariën, Alexey Vikhlinin, Serena Viti, Q. Daniel Wang, Fengwei Xu, Suinan Zhang, Qizhou Zhang

Publications

Paper I (Overview): Longmore & ACES Team (2026),  arxiv.org/abs/2602.20340

Paper II (Continuum): Ginsburg & ACES Team (2026),  arxiv.org/abs/2602.20240

Paper III (High-resolution lines, HNCO/HCO+): Walker & ACES Team (2026),  arxiv.org/abs/2602.20276

Paper IV (Intermediate-width lines): Lu & ACES Team (2026),  arxiv.org/abs/2602.20445

Paper V (Broad spectral windows): Hsieh & ACES Team (2026),  on arxiv.org tomorrow

Acknowledging ACES Data

When using ACES data products, please cite:

  • The ACES overview paper (Paper I; Longmore et al. 2026), and
  • The relevant data paper(s) that describe the specific products used
    • Continuum data reduction and products (Paper II; Ginsburg et al. 2026) 
    • Spectral line data reduction and high-resolution line products: HNCO, HCO+ (Paper III; Walker et al. 2026)
    • Intermediate-resolution line products: e.g., SiO, H13CO+, H13CN (Paper IV; Lu et al. 2026)
    • Broad spectral window line products: e.g., CS, HC3N, H40ɑ (Paper V; Hsieh et al. 2026)   

The ACES team recommends citing all papers in the initial series when using any ACES data products.

Please also cite the ALMA data as follows:

This paper makes use of the following ALMA data: ADS/JAO.ALMA#2021.1.00172.L. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

Other Resources

The ACES website can be found at: https://sites.google.com/view/aces-cmz/home

The accompanying ESO press release can be found at: https://www.eso.org/public/news/eso2603/