TA-57 Brief Description

March 1998 2 0 8 TA and Facilities Descriptions 4.33.1 Site Description TA-57 [Figure 4-33 (index map of TA-57)] is located about 28 mi (45 km) west of Los Alamos on the southern edge of the Valles Caldera in the Jemez Mountains. The 15-acre (6-ha) site lies on land leased from the US Forest Service, and the Laboratory’s use of the land is governed by a memorandum of understanding between the Laboratory and the Forest Service. The site includes the main area; a 2-acre (0.81-ha), 5-million-gallon (18,927,060-L) pond and two smaller ponds; and a housing area shared with the Forest Service. TA-57 is the location of environmental research, including the Laboratory’s Hot Dry Rock Geothermal Project and the Milagro Project, which investigates astronomical events. Fenton Hill was originally developed to study the use of hot dry rocks to generate geothermal energy. The Geothermal Project has been completed, and the site is now being proposed as the location for an astrophysics observatory. The proposed observatory would be dedicated to observations of objects that brighten in the night sky then quickly fade away. These objects include supernovae, flare stars, and brief, very-high-energy flashes from space called gamma-ray bursts. The proposed facility may also contribute to catalogs of near-Earth objects, including potential Earth-crossing comets and asteroids. The instruments planned for the Fenton Hill site are designed specifically to observe and record ephemeral flickers and flashes. As envisioned, the site will be home to a suite of telescopes dedicated to optical observations set for short time scales—from fractions of a second to hours. The short-time-scale exposures will allow broad searches of the sky and a chance to catch transient optical events before they vanish. The first optical telescope planned for Fenton Hill will be the Research and Education Automatically Controlled Telescope (REACT). REACT will be an automatic and robotic telescope that allows astronomers and astronomy students to search the sky from their computer terminals. REACT will have a narrow, one-half-degree field of view with high resolution. In its event-alert mode, REACT will automatically swing around to take a series of 1-min exposures to catch any optical signals coinciding with gamma-ray transients seen by other sky-watching instruments. REACT will be housed in a weather-sensing dome that will automatically close in the rain. The next instrument proposed for the site will be the Robotic Optical Transient Search Experiment (ROTSE I), a four-barreled system with 200-mm, wide-field lenses on electronic cameras. It will have an intermediate 15° field of view. ROTSE will use telemetry data from the National Aeronautics and Space Administration’s (NASA’s) Compton Gamma-Ray Observatory to direct its array of cameras toward burst events as they occur. Alerts will come from the fast-alert system developed by NASA at Goddard Space Flight Center. ROTSE will respond within 10 s of a burst onset. ROTSE will probably respond to alerts from BACODINE about once a week. The rest of the time ROTSE will spend its time watching comets. If a comet in the Kuiper Belt beyond Neptune happens to pass in front of our view of a star, ROTSE will record the tenth-of-a-second dip in light intensity from that star. The data may help detect and track comets long before they can be spotted from their own optical emissions. The new telescopes will stand beside an unusual observatory already in place at Fenton Hill called Milagro (the Milagro Project). Using more than 700 sensitive light detectors submerged in a 5-million- gallon (18,927,060-L) artificial pond, plus another 200 detectors arrayed around the pond, Milagro will record signals from high-energy cosmic emissions, including gamma-ray bursts. Milagro will stare continuously at the sky from horizon to horizon, day and night, acting like a camera whose shutter is always open. When Milagro alerts ROTSE, it will be watching the same piece of the sky, increasing the odds of capturing transient flashes. The water in the main pond is filtered to maintain its purity for use in environmental research.   ©2004 lasg.org