Long term spectral irradiance measurements of a 1000-watt xenon arc lamp

Spectral irradiance measurements over the range of 200 to 1060 nm were made on a 1000-watt xenon arc lamp over a period of 1500 hours. Four sets of measurements were made after periods of 70, 525, 1000, and 1500 hours of operation. The lamp (Hanovia Compact Xenon Arc Lamp) was mounted in the NASA Solar Irradiation System. When used in the System, the lamp is used as the radiating source for six test stations. Measurements were made of both the longterm stability (or variation of spectral irradiance as a function of time) and the actual spectral irradiance incident on the test specimen

The LION program Interim report

Review of development of LIO

IR-TF Relation In The Zone Of Avoidance With 2MASS

Using the Tully-Fisher relation, one can map the peculiar velocity field and estimate the mass in regions such as the Great Attractor. 2MASS is surveying the full sky in J, H and K bands and has the great advantage that it allows us to detect galaxies more uniformly to lower Galactic latitude than optical surveys. This study shows the feasibility of using 2MASS and the TF relation to probe large scale structure. We found that (i) we can use axis ratio $b/a$ up to 0.5; (ii) intrinsic extinction is present (up to 0.5mag at J, 0.1 mag at K); (iii) the zero-point of the TF relation is independent of the 2MASS magnitude measurement and is consistent with the HST Key-Project value; (iv) the 2MASS K-band 20th mag/arcsec$^2$ isophotal aperture magnitude produces the best TF relation; and (v) there is no type dependence of the residualsComment: 8 pages, Latex using newpasp.sty. Matches version to appear in Mapping the Hidden Universe: The Universe Behind the Milky Way - The Universe in HI, ASP Conference Series 2000, eds R.C.Kraan-Korteweg, P.A. Henning and H. Andernach (matched to published version; abstract bug in v2 fixed