CIM@21cm EU Horizon2020 Design Study proposal ? Cosmology with Intensity Mapping at 21 cm 6 June 2019 R. Ansari
Context • 21cm Intensity Mapping in the post reionisation epoch a complementary to optical surveys for cosmology and Dark Energy • Collaboration started with the US (UW. Wisconsin, CMU (Carnegie MellonUniv.) Fermilab …) in 2007 and then with NAOC China (2011) on IM • A small french group / project (BAORadio) with scientists from LAL (CNRS/IN2P3) , Obs. de Paris, CEA-Irfu - R&D in electronics, but also in data processing / analysis aspects • Working in the framework of the Tianlai project with NAOC & US scientists [ Two interferometers arrays, 3 cylinders with 2x96=192 feeds, 16 dish interferometer array with 2x16=192 feeds ] • PAON4 test interferometer (4 5-meter dishes) in Nançay • US Astro2020 decadal survey • An additional science topic for the french radioastronomy community, and french involvement in SKA
Design Studies Call opening: 25 July 2019 - Deadline: 12 November 2019
Current thinking • A proposal around science and technical studies, without any ( or major ?) hardware instrument deliveries • Target mostly Post Reionisation Epoch ( the redshift range z ~ 0 … 3 and maybe up to to z ~ 6) ? • Deliverable would be scientific papers and technical documents, such as TDR’s which could be used for di ff erent instrument projects, in the US, China (and maybe Europe) • Include studies involving use of existing instruments : FAST, SKA- MeerKat … • How such studies could be applied to SKA-phase 1 • Tianlai could be the pathfinder instrument providing the data to validate the modelings and simulations for IM with interferometer arrays ?
Design Study (DS) The activities to be performed in a Design Study proposal should include both: � Scientific and technical work, i.e. (1) the drafting of concepts, architecture and engineering plans for the construction, taking into due account resource efficiency and environmental (including climate-related) impacts, as well as, when relevant, the creation of prototypes; (2) scientific and technical work to ensure that the scientific user communities exploit the new facility from the start with the highest efficiency; (3) plans to organise the efficient curation, preservation and provision of access to data collected or produced by the future infrastructure, in line with the FAIR principles. � Conceptual work, i.e. (1) plans to coherently integrate the new infrastructure into the European landscape of related facilities in accordance, whenever appropriate, with the EU objective of a balanced territorial development; (2) the estimated budget for construction and operation, and initial ideas on how to achieve long-term sustainability; (3) plans for an international governance structure; (4) the planning of research services to be provided at international level, (5) procedure and criteria to choose the site of the infrastructure. The Commission considers that proposals requesting a contribution from the EU of between EUR 1 and 3 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts. Funding of PhD / postdocs and meetings & workshops Partners: Netherland , Sweden , UK (BINGO) , Italy � � – � �
CIM@21cm / tentative task list for the EU Design Study proposal ✴ Science with Intensity Mapping at 21 cm for z <~ 3 (or <6) to constrain cosmology: • LSS, BAO, … • Modified Gravity Inflation, Dark matter ? ... ✴ Cross-correlations with future optical surveys (LSST, DESI …) ✴ Synergies with mm lines (CO C …) Intensity Mapping ✴ Comparative study of various instrumental configurations ✴ Possibilities offered by existing instruments (FAST, SKA-MeerKat … ) ✴ Requirements specifications for dedicated instruments ✴ Data analysis challenges • Instrument calibration • 3D sky map reconstruction • Component separation, signal extraction • power spectrum and higher order statistics ✴ Beyond LSS : transient radio sky , FRB’s …
Il devient alors possible d’effectuer des relevés cosmologiques avec des instruments de plus petites The 21cm observation at high redshifts (z ~ 6-15) has attracted great interest among astrophysicists and cosmologists in the last 15-20 years. Several on-going experiments are attempting to observe the 21cm signal originating from the epoch of reionization (EOR), at redshift 6-15, when the hydrogen gas was reionized by the high energy photons (UV, X) emitted by the first stars, galaxies and quasars. LOFAR in Europe, MWA (Australia/USA), PAPER (South Africa/USA), HERA (South Africa/USA), 21CMA (China), and GMRT (India) are the main projects searching for the EoR signals. Some of these instruments, LOFAR and MWA in particular are among the SKA (Square Km Array) pathfinders. More recently, since 10 years, 21 cm Intensity Mapping has been proposed as a an innovative method to carry cosmological surveys, at lower redshifts (z ~1-3) to help answering fundamental questions such as the nature of the Dark Energy component of the universe. Indeed, mapping the universe in radio through the observation of the 21 cm emission of the neutral hydrogen is a complementary approach to that of the optical surveys to study Large Scale Structures (LSS) and the BAO’s, in the redshift range z <~ 3, or maybe even up to redshift z <~ 6. Intensity mapping correspond to the observation of total 21 cm emission from hundreds of galaxies, contained in cosmic cells of ~ 1000 Mpc^3, instead of detecting 21 cm emission from individual sources. Carrying cosmological through 21 cm Intensity Mapping becomes then possible using radio instruments with smaller collecting area and lower resolution, compared to SKA or FAST. Several instruments have been build or are planned to explore the intensity mapping method. The CHIME instrument in Canada features 3 large cylindrical reflectors, while two instruments have been built at the TIANLAI site in the Xinjiang province, in western China. One instrument has a design similar to CHIME, with 3 cylindrical defectors and a second instrument, a dish array with 16 6-meter reflectors. The HIRAX project (South Africa) plan to build a large dish array, with few hundred dishes, while BINGO will feature a single large reflector equipped with multi-feed receiver. The Tianlai instrument design has been carried by a an international collaboration, including US and french scientists, who are also involved also in the data analysis. The intensity mapping is also considered for the SKA mid-frequency instrument, despite a non optimal instrument configuration. The SKA dish array would not be used in this cas in interferometric mode. We plan to organise a consortium with European partners (France, Italy, Switzerland, UK) and international partners (China, US) to study the scientific reach of Intensity mapping, the synergies with optical surveys, such as LSST, DESI and Euclid and submit a Horizon 2020 DS (Design Study) proposal to support these activities. This ANR proposal aims and of getting the financial support necessary to create the network of partners, design the work packages, submit the proposal and contribute to raise the community interest in this subject, and in the SKA project. projet est retenu pour financement (sous réserve d’une mise à jour si besoin). En déposant un dossier,
Next steps / Questions • Enough interest to continue further ? • if Yes, do we (and how) extend the involved partners ? • What are other proposals being prepared with similar aims / subjects ? • Other questions to be listed / discussed
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