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Site Selection Working Group

Page history last edited by cdebreuc@eso.org 1 year, 9 months ago

Where will we build AtLAST?

Criteria to take into account:
- science requirements
- meteorological conditions: PWV, height (dry atmospheric component), windspeed, anamolous refraction, PWV stability
- Accessibility of the site, both for regular operations/maintenance, and in special circumstances (e.g. after major snow storms, for emergency evacuations, ...).
- Cost to build and operate the infrastructure.
- Possibility to use the telescope(s) to add extended baselines to ALMA (check correlation of PWV statistics with Chajnantor).
- Political stability, respect for local traditions, mining rights, ...

Sites to be considered (restricted to South America for now):
- 5100m Chajnantor Plateau (but need to specify where on the plateau, taking into account statistics on PWV, wind, baseline stability, etc.).
- 5612-5640m on Cerro Chajnantor.
- 5600m Cerro Chazcon.
- 5200m Cerro Toco (ACT).
- 5400m Cerro Honar.
- 5500m Cerro Sairecabur.
- Cerro Tolonchar (south of Chajnantor).
- Sites in Argentina, East of Chajnantor (e.g. LLAMA site Alto Chorillos 4820m).
- 3100m Cerro Mackenna (25km from Armazones).
Not to longer considered because of a showstopper:
- 6000m Acamarachi (also known as Pili) is a 6,046-metre (19,836 ft) high volcano: local traditions
- Cerro Quimal/Kimal (West of Chajnantor): local traditions
- ...

Deliverables and timescales:
- Present overview during the AtLAST meeting 17-19 January 2018.
- Select limited number of relevant talks for this meeting.
- Comparison of selected sites with criteria (e.g. "traffic light table"). Also compare with other submm sites worldwide such as the Antarctic sites (Dome A/C, South Pole), Mauna Kea, Pico de Orizaba (LMT, Mexico), Ali Observatory (Shiquanhe, Tibet), ...

Working group members:
- Carlos De Breuck (cdebreuc@eso.org)
- Bill Dent (Bill.Dent@alma.cl)
- Ryohei Kawabe (ryo.kawabe@nao.ac.jp)
- Florian Kerber (fkerber@eso.org)
- Satoki Matsushita (satoki@asiaa.sinica.edu.tw)
- Karl Menten (kmenten@mpifr-bonn.mpg.de)
- Lars-Ake Nyman (lars.nyman@alma.cl)
- Angel Otarola (aotarola@tmt.org)
- Juan-Pablo Perez-Beaupuits (jperezbe@eso.org)
- Simon Radford (simon.radford@cfa.harvard.edu)
- Marc Sarazin (msarazin@eso.org)
- Nicola Schneider (nschneid@ph1.uni-koeln.de)
- Tony Travouillon (tonyt@caltech.edu)
- Al Wootten (awootten@nrao.edu)

Collection of useful site selection studies and reports:
- Angels' page with links to site monitoring databases: https://project.tmt.org/~aotarola/ST/SITE_TESTING_AND_MONITORING.html
- Simon's paper comparing transparency at Maune Kea, South Pole and Chajnantor: http://adsabs.harvard.edu/abs/2016arXiv160208795R
- Marc's ESO Messenger's paper on APEX PWV predictions: http://adsabs.harvard.edu/abs/2013Msngr.152...17S
- http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013Msngr.152...17S&db_key=AST&link_type=ABSTRACT&high=598c491ca229322
- ALMA Long Baseline Workshop October 2017: http://alma-intweb.mtk.nao.ac.jp/~diono/meetings/longBL2017/
- Chilean labor laws stating the difference between <5500m and >5500m: https://www.leychile.cl/Navegar?idNorma=1045465
- Argentine site studies:
- Bareilles, F.~A., et al., 2011, Comparación entre los sitios de LLAMA y APEX, Boletin de la Asociacion Argentina de Astronomia La Plata Argentina, 54, 427 http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011BAAA...54..427B&db_key=AST&link_type=ARTICLE
- Bareilles, F.~A., et al., 2010, Alto Chorrillo: otra alternativa para instalar una antena para ondas milimétricas y submilimétricas en Argentina, Boletin de la Asociacion Argentina de Astronomia La Plata Argentina, 53, 199
- Bareilles, F.~A., Morras, R., Olalde, J.~C., Hauscarriaga, F.~P., \& Arnal, E.~M., 2007, Atmospheric opacity at 210 GHz: final results in North-West of Argentina (Puna Saltena), Boletin de la Asociacion Argentina de Astronomia La Plata Argentina, 50, 329 http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007BAAA...50..329B&db_key=AST&link_type=ARTICLE
- MOLIERE code: http://www.sciencedirect.com/science/article/pii/S0032063309001998

APEX study of PWV at Llano de Chajnantor
APPENDIX A - Atacama Astronomy Park - Site Boundaries.pdfAPPENDIX A - Atacama Astronomy Park - Site Boundaries.pdf

Addendum: measuring and forecasting PWV above La Silla, APEX and Paranal observatories

Presentation on Universidad de Valparaiso study of PWV predictions for Chajnantor


Study of Precipitable Water Vapor at Llano de Chajnantor- report by Universidad de Valparaiso


Minutes of telecons:
- 2017November9:

  • Attending: Al Wootten, Satoki Matsushita, Simon Radford, Carlos De Breuck
  • We discussed the site selection criteria and overview of various sites (updated on the wiki as a result)
  • Agreed that producing a "traffic light table" with criteria on one axis and sites on the other axis is a deliverable to the January AtLAST meeting.
  • Added number of useful links from previous site studies (e.g. talks from Long Baseline workshop).
  • Discussion on the usefulness to use a telescope like AtLAST as an outrigger telescope for ALMA long baselines. Among the participants, the feeling seems to be that this should not be a prime science driver (e.g. we shouldn't build AtLAST at elevations <4000m because of this).
  • AI Carlos: look at diurnal and annual statistics of APEX how much high windspeeds is a problem.APEXwindspeed.jpg
  • AI Satoki: try to obtained weather/PWV statistics from ASTE.
  • AI Carlos: invite Bill Dent to working group. Done, accepted.
  • AI Carlos: organize doodle poll for next telecon week of December 4-8. Done, see https://doodle.com/poll/hsudznhmgs6atvna


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