Assigned ID: 595 ----- Attempting Submission 1 (Fri Feb 24 19:13:11 GMT 2012) ----- I've set the buffer time to the actual exposure time (in sub exposure) - 110s, as directed by contact scientist. Visit passes all checks, including BOT, with only a single warning due to the fact that there's more exposures than FP positions. Re-submitted with corrected buffer times. ----- Attempting Submission 1 (Tue Jun 26 13:35:49 GMT 2012) ----- ----- Attempting Submission 2 (Tue Sep 11 05:30:37 GMT 2012) ----- Only one error, and is due to the fact that there's only 4 choices of FP and 6 exposures. So I use the format 1,2,3,4,2,3. The delicate balance between cooling and feedback processes is responsible for the slow build-up of massive elliptical galaxies in the cores of galaxy clusters. In the absence of feedback, the intracluster medium (ICM) should deposit ~1000 Msun/yr of cool material onto the central galaxy, leading to massive, starburst galaxies - a stark contrast to the passive, red galaxies we observe. Understanding this balance between radiative cooling in the hot ICM and feedback, likely from AGN, is critical to understanding the evolution of galaxies in the cluster environment. Recent observations have found significant evidence for ongoing star formation in central cluster galaxies (~1 Msun/yr), suggesting that this balance may be slightly off in favor of cooling. However, it is not possible from the current observations to distinguish between young stars forming in situ, fueled by the cooling ICM, or if they have been stripped from infalling, gas-rich galaxies. We propose a simple test, using the strongly-cooling cluster Abell 1795, to determine the origin of this young stellar population via far-UV COS spectroscopy. We show that, by combining these new data with our existing high spatial resolution, multi-wavelength dataset for this system, we will be able to a) identify intermediate-temperature gas, which would provide proof that the hot and cold phases are thermally coupled, and b) constrain, for the first time, the ages and metallicities of the stars in the extended, cooling filaments. This program will have a significant impact on our understanding of galaxy formation and cluster evolution, and may provide the first direct evidence of young stars condensing out of the ICM. We requested and were allocated 6 orbits to obtain UV spectroscopy of the star-forming filament in Abell1795 with COS. While the star-forming filament has been observed in the far-UV with ACS/SBC by us, the uncertainty on the UV peak is still at the level of ~0.4" due to the wavelength-dependent pointing shifts of ACS/SBC observations. We have used XMM-OM, GALEX, and SDSS images in order to confirm the peak UV position to within ~0.5", but require an ACQ/SEARCH exposure in order to be 100% confident that we are centered on the brightest UV peak. We then use ACQ/IMAGE to center to higher accuracy. The bright object tool was run using the GALEX catalog and returned no warning. All of our observations are done in TIME-TAG mode. This temporal sampling will allow us to exclude poor quality data and get improved thermal correction and background removal. We separate our exposures into six orbits, where each orbit uses one of four different FP_POS (1,2,3,4,2,3). This observing strategy is adopted to reduce the fixed pattern noise and fill up the wavelength hole produced by the chip gap without excessive overheads. Since our targets are faint, we use a BUFFER-TIME equal to the exposure time, as suggested in the users manual. STAR FORMATION 12 false 0.0 0.0 false false false false SUPPORTED STELLAR CLUSTER COOLING FLOW FILAMENT OB ASSOCIATION STAR FORMING REGION J2000 J2000 m_g = 19.9, m_FUV = 21.0 COS/FUV Spectroscopic No No G140L 1280 1347341344198 /private/var/folders/qz/6xc538sd58v6__qc44tt0mf40000gn/T/OPVisit7808408630730632253.xml The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 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