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Full-Text Articles in Physical Sciences and Mathematics
Further Investigation Of The Time Delay, Magnification Ratios, And Variability In The Gravitational Lens 0218 + 357, A. S. Cohen, J. N. Hewitt, C. B. Moore, Deborah B. Haarsma
Further Investigation Of The Time Delay, Magnification Ratios, And Variability In The Gravitational Lens 0218 + 357, A. S. Cohen, J. N. Hewitt, C. B. Moore, Deborah B. Haarsma
University Faculty Publications and Creative Works
High-precision VLA flux density measurements for the lensed images of 0218 + 357 yield a time delay of 10.1 +1.5-1.6 days (95% confidence). This is consistent with independent measurements carried out at the same epoch by Biggs and colleagues in 1999, lending confidence to the robustness of the time delay measurement. However, since both measurements make use of the same features in the light curves, it is possible that the effects of unmodeled processes, such as scintillation or microlensing, are biasing both time delay measurements in the same way. Our time delay estimates result in confidence intervals that are somewhat …
Faint Radio Sources And Star Formation History, Deborah B. Haarsma, R. B. Partridge, R. A. Windhorst, E. A. Richards
Faint Radio Sources And Star Formation History, Deborah B. Haarsma, R. B. Partridge, R. A. Windhorst, E. A. Richards
University Faculty Publications and Creative Works
The centimeter-wave luminosity of local radio galaxies correlates well with their star formation rate. We extend this correlation to surveys of high-redshift radio sources to estimate the global star formation history. The star formation rate found from radio observations needs no correction for dust obscuration, unlike the values calculated from optical and ultraviolet data. Three deep radio surveys have provided catalogs of sources with nearly complete optical identifications and nearly 60% complete spectroscopic redshifts: the Hubble Deep Field and Flanking Fields at 12h + 62°, the SSA13 field at 13h + 42°, and the V15 field at 14h + 52°. …