This file contains site location and orientation information, a convenient name for the detector, and filenames for the detector noise power spectrum and whitening filter, for 11 different detector sites. These site are:
(1) Hanford, Washington LIGO site,As explained below, information for additional detector sites can be added to detectors.dat as needed. [In fact, there are many additional sites currently in the file - look at it to see for yourself. For example, this file and the referenced parameter files now include the 7 distinct stages of ``enhanced LIGO". Thus a given site, for example the Hanford Washington LIGO site, has a number of different entries, corresponding to different noise power spectra.]
(2) Livingston, Louisiana LIGO site,
(3) VIRGO site,
(4) GEO-600 site,
(5) Garching site,
(6) Glasgow site,
(7) MIT 5 meter interferometer,
(8) Caltech 40 meter interferometer,
(9) TAMA-300 site,
(10) TAMA-20 site,
(11) ISAS-100 site.
The data contained within this file is formatted as follows: Any line beginning with a # is regarded as a comment. All other lines are assumed to begin with an integer (which is the site identification number) followed by five floating point numbers and three character strings, each separated by white space (i.e., one or more spaces, which may include tabs). The first two floating point numbers specify the location of the central station (the central vertex of the two detector arms) on the earth's surface: The first number is the latitude measured in degrees North of the equator; the second number is the longitude measured in degrees West of Greenwich, England. The third floating point number specifies the orientation of the first arm of the detector, measured in degrees counter-clockwise from true North. The fourth floating point number specifies the orientation of the second arm of the detector, also measured in degrees counter-clockwise from true North. The fifth floating point number is the arm length, in cm. The three character strings specify: (i) a convenient name (e.g., VIRGO or GEO-600) for the detector site, (ii) the name of a data file that contains information about the noise power spectrum of the detector, and (iii) the name of a data file that contains information about the spectrum of the whitening filter of the detector. (We will say more about the content and format of these two data files in Secs. and .) The information currently contained in detectors.dat is shown below:
Site information for new (or hypothetical) detectors can be added to detectors.dat by simply adhering to the above data format. For example, as the noise in the LIGO detectors improves, one can accommodate these changes in detectors.dat by adding additional lines that have the same site location and orientation information as the ``old'' detectors, but refer to different noise power spectra and whitening filter data files. The only other requirement is that the site identification numbers for these ``new and improved'' detectors be different from the old site identification numbers, so as to avoid any ambiguity. Explicitly, one could add the following lines to detectors.dat to include information about the advanced LIGO detectors:
The file detectors.dat currently resides in the
parameters subdirectory of GRASP.
In order for the stochastic background routines and example
programs that are defined in the following sections to be able to
access the information contained in this file, the user must set
the environment variable GRASP_PARAMETERS to point to this
For example, a command like:
setenv GRASP_PARAMETERS /usr/local/GRASP/parameters
should do the trick. If, however, you want to modify this file (e.g., to add another detector or to add another noise curve), then just copy the detectors.dat file to your own home directory, modify it, and set the GRASP_PARAMETERS environment variable to point to this directory.