Expressions of Intent for IPY 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Search for large scale polarization of the Cosmic Microwave Background  (MiPol: Milano Polarimeter)

Outline
The current interest on the Cosmic Microwave Background is aimed to measure the linear polarization (CMBP). CMBP will help us to accurately evaluate cosmological parameters and answer open questions regarding the inflationary paradigm. Two modes E- and B- are expected. Their detection will provide answers to different questions. So far only very preliminary indications supporting the existence of E-modes have been obtained by DASI and WMAP. At large angular scales the amplitude of CMBP is related to the existence of a re-ionization epoch in the post-recombination Universe. A relevant re-ionization epoch, together with a concrete possibility to detect CMBP at scales around 10deg, is suggested by WMAP observations. B-modes are expected at levels definitely lower than E-modes. Due to the relevance of CMBP for Cosmology it is mandatory to confirm the detection of E-modes. This is the goal of MiPol, observing at large angular scale. Inside the wider programme to study CMBP from Dome C, including MiPol, BAR-SPOrt will investigate E-modes at smaller scales, while BRAIN and Clover will look for B-modes. The faint signals of CMBP require instruments free from systematics, which set the current limitation to the sensitivity. The sky emission is among the major source of spurious signals: therefore it is important to observe from an extremely stable site in order to perform a long-time integration. The Antarctic Plateau is the best place on the ground: Dome C is better than South Pole, being higher, dryer and more stable. MiPol is a correlation radiometer: frequency=33GHz; resolution=7deg; outputs = Stokes parameters U and Q. Front-end is cooled down to 20K, by a mechanical cryogenerator, avoiding cryogenic liquids. MiPol can operate for months without manpower and is ideal for long-duration winter experiments in Antarctica. It is housed in an Antarctic tent (only the mouth of the horn looks outside) so the system temperature is stabilized close to 300K and the temperatures of electronics and cryogenics are accurately controlled to avoid gain drifts and prevent failures. The present experimental set-up has been optimized following the indications of preliminary campaign (Dome C, 1998/99). MiPol is currently installed at Testa Grigia (Italian Alps, 3480m asl), where it has been extensively tested. It is now ready to be moved and operated at Dome Concordia: installation during summer 2005/06; observations during winter 2006 and repeated in winter 2007. The instrument will be aimed at the SCP: high galactic latitude regions are important to search for CMBP, galactic plane regions to study galactic foreground and polarized emission of spinning dust.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
Theme 4 – The proposed activity, as a part of a larger effort addressed to the study of the CMBP, can contribute to the understanding of the Universe at the present time and of the physics processes occurred in the remote epochs. Theme 5 – The installation of automated experiments for astrophysics and Cosmology research at Dome Concordia is the starting step for the building of a stable observational facility.

What international collaboration is involved in this project?
The proposed activity involves scientists from Italy (University of Milano Bicocca) and France (CESR/CNRS Toulouse).

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
We propose to install MiPol at the Dome Concordia station – Antarctica.

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: 12/2005 – 01/2007      01/2007 – 02/2008      

Significant facilities will be required for this project:
The activity will take place in an existing field station: Dome Concordia. The instrumentation can be delivered to Dome C using a small-size transport aircraft. In any case the activity will be supported by the logistics of the station, shared among all the other projects.

Will the project leave a legacy of infrastructure?
The proposed activity regard the installation of an automated experiment, which will be removed at the end of the observations. But it can represent the starting step for a stable astrophysical observatory, whose realization has been already proposed.

How is it envisaged that the required logistic support will be secured?
Consortium
Own national polar operator

The proposed instrumentation, in a preliminary configuration, has been already operated at Dome C during the summer 1998-99. On the base of this experience the instrumental set-up has been adapted to be reliable for a winter operation.

Has the project been "endorsed" at a national or international level?
The research activity of MiPol has been funded in the last years by Italian Antarctic Program (PNRA/CSNA).

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
Expansion
The experiment is part of a wider programme to study the CMBP emission from Dome-C, exploiting the unique environmental conditions of the site (thermal stability, no winter Sun illumination, and atmosphere transparency). This includes the proposed experiments BaR-SPOrt, BRAIN/ClOVER, and MiPol.

How will the project be organised and managed?
The program will be managed by the scientists of the University of Milano Bicocca, where the experiment has been developed, with the collaboration of the CESR/CNRS.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
Several students are involved in the proposed activity and both Degree and PhD thesis have been produced. Outreach and communication issues will be co-ordinated within the activities of CMBP measurement from Dome Concordia.

What are the initial plans of the project to address data management issues (as outlined in the Framework document)?
Scientific data will be immediately available to all the people of the collaboration. Besides data can be distributed to the scientific community on the base of a scientific collaboration agreement.

How is it proposed to fund the project?
The development of the instrument has been already funded. We have requested to PNRA/CSNA to fund the field activity in Antarctica.

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Dr Massimo Gervasi
Physics Department
Piazza della Scienza, 3
Milano
20126
Italy

Tel: +39.02.6448.2829
Mobile:
Fax: +39.02.6448.2888
Email:

Other project members and their affiliation

Other Information