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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:
-http://legacy.nrao.edu/alma/site/
- 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
http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011RMxAC..41...20C&db_key=AST&link_type=ABSTRACT&high=598c491ca229322
http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010SPIE.7733E..4KC&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-ESO-TRE-0022-R1.00.pdfAPEX-ESO-TRE-0022-R1.00.pdf

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
ESO-PWV-Chajnantor-slides.pdfESO-PWV-Chajnantor-slides.pdf

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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