Astronomical Research with the Owens Valley Millimeter Array

ast - 9314079。加州理工学院。该奖项支持加州理工学院欧文斯谷毫米波阵列的研究、技术发展和学生教育。该阵列由6个直径10.4米的精密天线组成，目前可以定位到南北220米和东西200米的最大间距。所有望远镜都配备了双通道（2.6和1.3毫米）低温si接收器。在较短的波长下，阵列所能达到的最高角分辨率为1角秒。目前，大约50%的观测时间是由非加州理工学院的天文学家进行的。在过去三年的资助期间，欧文斯谷阵列获得了分子发射的孔径合成图像，范围从演化恒星的外壳到银河系的恒星形成区域，以及其他星系的旋臂和活动核；在红移高达3.2的高红移类星体和超亮星系中已经检测到一氧化碳的发射。在上一个拨款期间，天文台也取得了若干技术进步，包括建造和安装3个额外的天线，安装新的波束传输光学装置，实现完全的远程接收器调谐能力，建造一个新的数字相关器和光纤传输和延迟线系统。在未来三年的拨款期内，天文台的科学项目将包括研究高红移星系和原星系、红外发光星系、宇宙的大尺度结构、原恒星和原行星状星云、银河系的结构、年轻恒星的准直流出物、星际化学和各种太阳系天体。1994-1997年期间计划的技术发展包括采用带集成第一级中频放大器的边带分离接收机，将干涉仪基线增加一倍，为每条基线采用第二个连续通道，以及在每台望远镜上开发和测试低噪声稳定辐射计，以测量和补偿降低阵列灵敏度的短期大气相位波动。特别是在大基线上。

AST-9314079. California Institute of Technology. PI: N. Z. Scoville Astronomical Research with the Owens Valley Millimeter Array This award supports research, technological development and student education at the California Institute of Technology's Owens Valley millimeter array. The array is made up of 6 precision 10.4m- diameter antennas, which currently can be positioned out to maximum spacings of 220m north-south and 200m east-west. All the telescopes are equipped with dual-channel (2.6 and 1.3mm) cryogenic SiS receivers. At the shorter wavelength, the highest angular resolution attainable by the array is 1 arcsecond. Approximately 50% of the array's observing time is presently devoted to investigations by non-Caltech astronomers. During the tenure of the past three year grant, the Owens Valley array has obtained aperture synthesis images of molecular emission in domains ranging from the envelopes of evolved stars, to star- forming regions in the Galaxy, as well as the spiral arms and active nuclei of other galaxies; carbon monoxide emission has been detected in high redshift quasars and ultraluminous galaxies at redshifts as high as 3.2. During the last grant period, the observatory also made a number of technical advances, including the construction and placement in service of 3 additional antennas, installation of new beam transport optics, implementation of fully remote receiver tuning capability, construction of a new digital correlator and fiber-optic transmission and delay line system. In the next three year grant period the observatory's scientific programs will include studies of high-redshift galaxies and protogalaxies, infrared-luminous galaxies, the large-scale structure of the Universe, protostars and protoplanetary nebulae, the structure of the Milky Way Galaxy, collimated outflows from young stars, interstellar chemistry and a variety of solar system objects. Planned technical developments in the 1994-1997 period include the intr oduction of sideband separation receivers with integrated first-stage IF amplifiers, doubling the interferometer baseline, introduction of a second continuum channel for each baseline, and the development and testing of low-noise stable radiometers on each telescope to measure and compensate for short- term atmospheric fluctuations in phase which reduce the sensitivity of the array, particularly over large baselines.