Submm/FIR astronomy from Antarctica

An ARENA workshop - Submm/FIR Astronomy from Antarctica

Submm/FIR astronomy from Antarctica

CEA Saclay - June 25-27th - Framework: ARENA
Organisers: V. Minier and P.-O. Lagage

Objective and Summary of the workshop

An ARENA workshop on Submillimetre Astronomy at Dome C was held in June 2007 at CEA Saclay, France. 75 people participated to a truly European meeting with participants from Sweden, UK, Spain, Portugal, Belgium, the Netherlands, Germany, Italy and France as well as guests from the US and Australia. This section gives an overview of the workshop objective, programme and results as follows:

Objective of the workshop
Programme with attached presentations
Summary and conclusions (science cases; site testing roadmap)
List of participants

A more complete, synthetised and written summary will be presented at the 2nd ARENA conference in Potsdam on 17-21 September 2007. This paper will be based on the presentations given at the Saclay workshop.

1. Objective of the workshop

1.2 Scientific rationale

Submillimetre (submm) astronomy is the prime technique to unveil the birth and early evolution of a broad range of astrophysical objects of the “cold Universe”. Submm continuum observations are particularly powerful to measure the luminosities, temperatures and masses of cold dust emitting objects. Examples of such objects include star-forming clouds in our Galaxy, prestellar cores and deeply embedded protostars, proto-planetary disks around young stars, as well as nearby starburst galaxies and dust-enshrouded high-redshift galaxies in the early Universe.

A major obstacle to carry out submm observations from ground is the atmosphere. Astronomical observations in the FIR/submm/THz spectral bands (e.g. 200, 350, 450 µm) can only be achieved from cold, dry and stable sites with ground-based telescopes or from space to overcome the atmosphere opacity and instability that are mainly due to water vapour absorption and fluctuations in the low atmosphere. Chile currently offers the best accessible (all-year long) sites on Earth, where the precipitable water vapour (PWV) content is often less than 1 mm. Chile hosts the European facilities for submm/mm astronomy such as ESO VLT, APEX and the Chajnantor plateau (5100m) will be the ALMA site. However, THz/submm are only possible with PWV drops below 0.5 mm, which occurs less than 25% of wintertime at the ALMA site. At longer term, and particularly if global warming severely restricts the 200-350-450-µm windows on Chilean sites, Antarctica conditions with less than 0.2 mm PWV, could offer an exciting and unique alternative for ground-based THz/submm astronomy. This is an attractive opportunity for the 200-µm windows, especially, which are normally explored with Space telescopes (e.g. Herschel).

1.2 Key questions

The workshop will be entitled "Submillimetre/TeraHertz/Far-infrared Astronomy from Antarctica: Toward a large single-dish telescope at Dome C ?" and will be a *science driven* meeting. It will be organised within the framework of ARENA under the activity: NA5.2, New windows in the FIR/submm (150-500 microns).

Which science? As a primary goal, the workshop will identify unique scientific cases for which submm/THz observations with large (ground-based) telescopes are essential to make a big step in understanding the cold Universe (proto-planetary disk, star formation, high-redshift proto-galaxies and cosmology).

Which instrument and telescope? The workshop will therefore aim to discuss the possibility and the feasibility of installing a large (>10 m) single-dish antenna at Dome C and whether this telescope should be a dedicated instrument or an international facility. Logistics and cost vs. benefit in comparison with Chajnantor site will also be discussed.

Is Dome C the best site? Present knowledge of the atmospheric transmission in the FIR/submm windows and future site testing campaigns will be presented.

2. Programme and presentations (click on title to download)

2.1 Submm/FIR astronomy context (chair: P.-O. Lagage)

Welcome
Pierre-Olivier Lagage (CEA Saclay)

ARENA overview and prospect for submm astronomy
Nicolas Epchtein (LUAN/Nice and ARENA coordinator)

Submm astronomy context: ESO
Carlos De Breuck (ESO Garching)

Submm astronomy context: IRAM and the PdBI
Roberto Neri (IRAM Grenoble)

Space and airborne mission for submm astronomy
Frank Helmich (SRON - originally scheduled on monday)

Dome C: climate and atmospheric conditions
Hubert Gallée (LGGE Grenoble)

Astronomy at Dome C: an overview
Eric Fossat (LUAN Nice)

Submillimetre/Far-Infrared Astronomy from Antarctica: objective of the workshop
Vincent Minier (CEA Saclay)

2.2 Origin and evolution of stars and planets (chair: L. Olmi)

Protoplanetary disks – lines and continuum
Eric Pantin (CEA Saclay)

Molecular Spectroscopy and star formation in the 1-2 THz regime
Carsten Kramer (University of Cologne)

Submillimetre continuum emission of dust grains as probe of star formation
Philippe André (CEA Saclay)

An infrared study of Southern Dark Clouds
Paolo Persi (IASF INAF Rome)

LMC/SMC
Frank Israel (Leiden)

Star formation in local galaxies
Jonathan Braine (L3AB Bordeaux)

Evolved stars
Hans Olofsson (Onsala)

2.3 Galaxy formation and evolution (chair: C. de Breuck)

Local active galaxies
Luigi Spinoglio (INAF Rome)

FIR & sub-mm Extragalactic Surveys & Confusion Limits
Mattia Vaccari (Padova)

Galaxy evolution with wide field bolometric arrays at Dome C
Emanuele Daddi (CEA Saclay)

Precise measurement of CMB polarisation from Dome-C: the BRAIN experiment
Michel Piat (APC Paris)

2.4 Which telescope and feasibility (chair: J.-P. Swings)

South Pole Telescope
Tony Stark (CfA Harvard)

From the South Pole to Dome C: applying AST/RO experience
Nick Tothill (Exeter)

CONDOR: a 1.4 THz Heterodyne receiver
Martina Wiedner (Cologne)

Bolometer camera for submm/FIR
Louis Rodriguez (CEA Saclay)

Scientific programmes at the Concordia station and logistics
Yves Frenot (Deputy director of IPEV) & Patrice Godon (IPEV)

COCHISE - a 2.6-m submm/mm telescope at Dome C
Lucia Sabbatini (Rome 3)

The ALMA antennas
Pascal Lapeyre (Thales Alenia Space) & Luigino Giacomel (EIE)

Antarctic Submillimetre Observatory
Luca Olmi (INAF & U. Puerto Rico)

Management of a large astronomical facility at Dome C
Wolfgang Ansorge (RAMS-CON Germany)

2.5 Is Dome C the best site ? (chair: M. Sarazin)

Atmospheric Transmission Modelling
Pepe Cernicharo (DAMIR Madrid)

What we know about atmospheric transmission at Dome C
Luca Valenziano (IASF Bologna)

Site testing and PILOT – UNSW project past and present
John Storey (UNSW Sydney)

Submm & THz Astronomy at Cardiff University: possible commitments in Antarctica
Paolo Calisse (Cardiff)

The Receiver Lab Telescope: ground-based THz astronomy in Chili
Dan Marrone (SAO Harvard)

Submm camera for the ELT: potentials and impacts of telescope site selection
Ralf Siebenmorgen (ESO and SCELT team)

Concluding remarks on Science and Site testing
Pierre Olivier Lagage (resp. of ARENA NA5.2), Luigi Spinoglio (co-chair SOC), Vincent Minier (co-chair SOC)

3. Summary and conclusions

3.1 Science: concluding remarks

A brief set of conclusions and remarks are given here (see presentation above in the programme).

For any project it is crucial to have a very strong scientific case.
Good progresses have been made at this meeting, but more work is needed to strenghen scientific cases in the perspective of the Potsdam conference on Science at Dome C.
Sciences cases :
- LMC/SMC: the nature of the submm excess ? It needs hundreds days of observation with a 12-m telescope (see talk by F. Israel).
- CIB/Extragalactic: "clear opportunity windows for new science in galaxy formation and evolution exist for 200-450 µm imaging at Dome C, crucial redshift range 1<3" in E. Daddi's talk. Mapping with a 25-m telescope will be a truly major accomplishment.
- THz spectral lines are also potential niches (see talks by C. Kramer, or M. Wiedner).

Telescopes: find a cheap "path finder" or move directly to a large single dish telescope ?
- PILOT: a 2.4 m telescope that could operate at 200 µm (see talk by J. Storey). Around 2011.
- An ALMA-type antenna of 12 m in diameter: need a design study, but can be built by 2012.
- A larger antenna, 25-m class ?

Funding ?
- Not easy to find.
- ALMA and ELT will probably pump funding from Europe/ESO.

3.2 Site testing experiments: a proposed roadmap

A clear point addressed during workshop was the Site Testing issue. We agree to start as soon as possible site testing for submm astronomy based on the following "roadmap". Note that we need to have a synergy with all site testing experiments when possible (balloon, meteo modelling, infrastructure, IR/optical site testing...)

Environmental site testing:
Goal: how to protect, operate and supply in power a large facility in the harsh antarctic environment.
Instruments: GIVRE experiment, Cochise, Photovoltaics power supply experiments...

Atmospheric transmission site testing:
Goal: how well the FIR/submm/THz windows open at Dome C ?
Instruments:
- modelling: ATM and MOLIERE codes
- multi-wavelength tipper -> measure the transmission at 200, 350 and 450 microns
- 183 GHz + 60 GHz water vapour radiometer -> determine the Precipitable Water Vapour content in the atmosphere
- FTS (e.g. CASPER2) -> determine the full transmission spectrum and the width and shape of the atmospheric windows.

Sky noise site testing and first sky images
Goal: is the sky noise at Dome 10-50 times lower than at Chajnantor/Atacama ?
Instrument: CAMISTIC, 256-pixel bolometer array on IRAIT.

Spectral line observability at Dome C
Goal: check a couple of high interest lines
Instrument: heterodyne receiver...? Not clearly planned.

4. List of participants

André Philippe (CEA Saclay, France)
Ansorge Wolfgang (RAMS-CON, Germany)
Bontemps Sylvain (Bordeaux, France)
Boulade Olivier (CEA Saclay, France)
Braine Johnathan (Bordeaux, France)
Brinchmann Jarle (CAUP, Portugal)
Cadelis Louis (CEA Saclay, France)
Calisse Paolo (Cardiff, UK)
Candidi Maurizio (IFSI/INAF Rome, Italy)
Cernicharo Pepe (DAMIR Madrid, Spain)
Coudé Foresto Vincent (Observatoire de Paris, France)
Daddi Emanuele (CEA Saclay, France)
De Breuck Carlos (ESO Garching)
Déchellette Typhaine (Observatoire de Paris, France)
Durand Gilles (CEA Saclay, France)
El Khouloudi Samir (CEA Saclay, France)
Epchtein Nicolas (LUAN Nice, France and ARENA coordinator)
Fossé David (Ciel & Espace Paris, France)
Frenot Yves (IPEV, France)
Galabru Julien (Ministère, France)
Gallée Hubert (LGGE Grenoble, France)
Gérin Maryvonne (Observatoire de Paris, France)
Giacomel Luigino (EIE, Italy)
Giraud-Héraud Yannick (APC Parid 7, France)
Godon Patrice (IPEV, France)
Helmich Franck (SRON, The Netherlands)
Israel Franck (Leiden, The Netherlands)
Kramer Carsten (KOSMA Cologne, Germany)
Lagage Pierre-Olivier (CEA Saclay, France)
Lapeyre Pascal (Thales Alenia Space Toulouse, France)
Le Bertre Thibault (Observatoire de Paris, France)
Lequeutre Perrine (CEA Saclay, France)
Lestrade Jean-François (Observatoire de Paris, France)
Lortholary Michel (CEA Saclay, France)
Marrone Dan (Uni. of Chicago, US)
Minier Vincent (CEA Saclay, France)
Montanari Chiara (PNRA, Italy)
Mora Alcione (UAM, Spain)
Morin Bertrand (CEA Saclay, France)
Motte Frédérique (CEA Saclay, France)
Neri Roberto (IRAM Grenoble)
Olmi Luca (INAF Arcetri, Italy & Uni. of Puerto Rico)
Olofsson Hans (OSO, Sweden)
Pagani Laurent (Observatoire de Paris, France)
Pajot François (IAS, France)
Pantin Eric (CEA Saclay, France)
Péronne Marie-Laure (LUAN, France)
Persi Paolo (INAF Rome, Italy)
Piat Michel (APC Paris 7, France)
Pierre Alain (IPEV, France)
Polenta Gianluca (La Sapienza Rome, Italy)
Relland Johan (CEA Saclay, France)
Rocca-Volmerange Brigitte (IAP, France)
Rodriguez Louis (CEA Saclay, France)
Sabbatini Lucia (Uni. of Rome 3, Italy)
Saraceno Paolo (INAF Rome, Italy)
Sarazin Marc (ESO Garching)
Schneider Nicola (CEA Saclay)
Siebenmorgen Ralf (ESO Garching)
Spinoglio Luigi (INAF Rome, Italy)
Stark Tony (CfA Harvard, US)
Storey John (UNSW Sydney, Australia)
Swings Jean-Pierre (Liège, Belgium)
Talvard Michel (CEA Saclay, France)
Tothill Nick (Exeter, UK)
Toutain Christine (CEA Saclay, France)
Vaccari Mattia (Padova, Itlay)
Valenziano Luca (IASF Bologna, Italy)
Vauglin Isabelle (Lyon, France)
Veyssière Christian (CEA Saclay, France)
Wiedner Martina (Cologne, Germany)
Willmann Guillaume (CEA Saclay, France)