High altitude wind velocity at Sierra Negra and San Pedro M\'artir

It has been proposed that the global circulation of the atmosphere winds at 200 mb can be used as a criteria to establish the suitability of a site for the development of adaptive optics techniques such as slow wavefront corrugation correction. By using the NOAA NCEP/NCAR Reanalysis data base we analyze the monthly average wind velocity at 200 mb for a 16 year period, for two sites in Mexico: Sierra Negra and San Pedro M\'artir. We compare the results with those obtained for Mauna Kea, Paranal and La Silla, with Maidanak in Uzbekistan, and with Gamsberg in Namibia. We show that for all the sites under study there is a yearly wind speed modulation and we model that modulation. Our results show that Sierra Negra and San Pedro M\'artir are comparable with the best observatory sites as Mauna Kea and are amongst the most advantageous sites to apply adaptive optics techniques.Comment: Accepted for publication in PASP; 14 pages, 6 tables, 2 figure

Optical Seeing at Sierra Negra

Optical seeing measurements carried out at Sierra Negra, the site of the Large Millimeter Telescope, are reported. The site, one of the highest peaks of Central Mexico, offers good coverage of Northern and Southern hemispheres and we have undertaken several campaigns to investigate the astronomical potential of the site in the optical. Here we report on our campaign aimed at establishing the seeing quality of the site. We present data of the first three campaigns of optical seeing monitoring covering from February 2000 to May 2002, carried out with a Differential Image Motion Monitor. The results clearly indicate a sub-arcsec seeing, better statistics during the dry season and no dependence with the time of night. We find no dependence of our results with the integration time used.Comment: Accepted for publication in the July 2003 issue of the PAS

The European Large Area ISO Survey IX: the 90 micron luminosity function from the Final Analysis sample

We present the 90 micron luminosity function of the Final Analysis of the European Large Area ISO Survey (ELAIS), extending the sample size of our previous analysis (paper IV) by about a factor of 4. Our sample extends to z=1.1, around 50 times the comoving volume of paper IV, and 10^{7.7} < h^{-2}L/Lsun < 10^{12.5}. From our optical spectroscopy campaigns of the northern ELAIS 90 mircon survey (7.4 deg^2 in total, to S(90um)>70mJy), we obtained redshifts for 61% of the sample (151 redshifts) to B<21 identified at 7 microns, 15 microns, 20cm or with bright (B<18.5) optical identifications. The selection function is well-defined, permitting the construction of the 90 micron luminosity function of the Final Analysis catalogue in the ELAIS northern fields, which is in excellent agreement with our Preliminary Analysis luminosity function in the ELAIS S1 field from paper IV. The luminosity function is also in good agreement with the IRAS-based prediction of Serjeant & Harrison (2004), which if correct requires luminosity evolution of (1+z)^{3.4 +/- 1.0} for consistency with the source counts. This implies an evolution in comoving volume averaged star formation rate at z<~1 consistent with that derived from rest-frame optical and ultraviolet surveys.Comment: MNRAS accepted. 7 pages, 5 figures. Uses BoxedEPS (included