Astronomical Research with the Owens Valley Millimeter Array

AST-9314079。加州理工学院。PI：N。Z. 斯科维尔 欧文斯谷毫米波天线阵的天文研究 该奖项支持加州理工学院欧文斯谷毫米阵列的研究、技术开发和学生教育。该阵列由6个精确的10.4米直径的天线组成，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）低温硅接收器。在较短的波长下，阵列可达到的最高角分辨率为1角秒。 目前，该阵列大约50%的观测时间用于非加州理工学院天文学家的调查。 在过去三年的赠款期内，欧文斯谷阵列获得了从演化恒星的包层到银河系中的星星形成区以及其他星系的旋臂和活动核的分子发射孔径合成图像;在高红移类星体和超亮星系中，在高达3.2的红移处检测到一氧化碳的排放。在上一个资助期内，天文台亦取得了多项技术进展，包括建造并投入服务的三个额外天线、安装新的光束传输光学系统、实施完全远程接收器调谐能力、建造新的数字相关器和光纤传输及延迟线系统。在未来三年的资助期内，天文台的科学计划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、原恒星和原行星星云、银河系的结构、年轻恒星的准直外流、星际化学和各种太阳系物体。计划在1994-1997年期间进行的技术发展包括引进带集成第一级中频放大器的边带分离接收机，使干涉仪基线加倍，为每个基线引进第二个连续谱信道，以及在每台望远镜上研制和测试低噪声稳定辐射计，以测量和补偿短时间的辐射，长期大气波动的相位降低了阵列的灵敏度，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.