We consider the optimal site selection of future generations of gravitational wave detectors. Previously, Raffai et al. optimized a 2-detector network, applying a combined figure of merit, and extended this optimization to networks with more than two detectors in a limited way by first fixing the parameters of all other component detectors. In this work we now present a more general optimization that allows the locations of all detectors to be simultaneously chosen. We follow the definition of Raffai et al. on the metric that defines the suitability of a certain detector network. Given the locations of the component detectors in the network, we compute a measure of the network’s ability to distinguish the polarization, constrain the sky localization and reconstruct the parameters of a gravitational wave source. We further define the ’flexibility index’ for a possible site location, by counting the number of multi-detector networks with a sufficiently high FoM that include that site location. We confirm the conclusion of Raffai et al., that Australia hosts the best candidate site to build a future generation gravitational wave detector. This conclusion is valid for either a 3-detector network or a 5-detector network. For a 3-detector network site locations in Northern Europe display a comparable flexibility index to sites in Australia. However for a 5-detector network, Australia is found to be a clearly better candidate than any other location.
The paper was published with open access in Classical and Quantum Gravity and was advertised on the journal's companion website CQG+.
You can find an online version of the paper on arxiv: Global Optimization for Future Gravitational Wave Detectors' Sites
The Geographic Exclusion Map (GEM) is a map of the Earth indicating locations that are excluded or allowed by our criteria of acceptable construction sites, detailed in the paper. GEM has a resolution of 8015*4411 pixels which means a ~5 km resolution along the Equator. The map is available both in Mercator and Geographic projections.
Pixels allowed or excluded based on certain criteria are denoted by the following colors:
| Layer | Color | Notes |
| allowed sites | black | |
| coastlines | dark blue | Areas closer than 100 km to oceans and seas. |
| seismically active areas | red | A 200 km wide strip along the tectonic plate lines (source: Exclusion based on tectonic plate lines.) |
| oceans | blue | Self-explanatory. |
| roads | dark brown | Roads of North America. (data source) |
| elevated areas | brown | Areas above 2000 m. (data source) |
| protected areas | green | National parks and other protected areas. (data source) |
| sweetwaters | blue | Rivers and lakes. (data source) |
| populated areas | yellow | Bright areas on the NASA nightlights map and other populated areas of India and China. (data source I and data source II) |
| high gradient areas | claret | Areas with higher than 5° slope. (data source) |
The Geoblacklist database is an ASCII text file that was created from the Geographic Exclusion Map (proper name: lat66.5-5km-colormap-C100km-S200km-O-R-E2000m-Pro-W-Pop-Pol.tif) by reading out and storing the geographical latitude and longitude coordinates of every non-black pixel. The file geoblacklist.txt contains three columns: Latitude; Longitude; index. Each row specifies a geographical location on Earth's surface in Lat/Long coordinates with an index defining the exclusion criteria of that geographic coordinate.
Indices of different exclusion criteria are the following (the indices work as links to ASCII files that contain the Latitude and Longitude coordinates, respectively, of geographical locations excluded from GEM based on that criterion):
1 - coastlines (171.8 MB)
2 - seismically active areas (181.4 MB)
3 - oceans (594.4 MB)
4 - roads (7.6 MB)
5 - elevated areas (12.9 MB)
6 - protected areas (33.2 MB)
7 - sweetwaters (12.8 MB)
8 - populated areas (5.1 MB)
9 - high gradient areas (4.1 MB)
Nandor Kelecsenyi, Peter Raffai
Eotvos
Gravity Research Group
MTA-ELTE EIRSA 'Lendulet' Astrophysics
Research Group
1117 Budapest, Hungary
Contact:
praffai"AT"bolyai"DOT"elte"DOT"hu
Page last updated: 03/13/2015