Kamal Souccar

The AzTEC mm-wavelength camera

AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Here, we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three-month observing campaign at the James Clerk Maxwell Telescope and conclude with our plans for AzTEC as a facility instrument on the Large Millimetre Telescope.

First Surface-resolved Results with the Infrared Optical Telescope Array Imaging Interferometer: Detection of Asymmetries in Asymptotic Giant Branch Stars

We have measured non-zero closure phases for about 29% of our sample of 56 nearby Asymptotic Giant Branch (AGB) stars, using the 3-telescope Infrared Optical Telescope Array (IOTA) interferometer at near-infrared wavelengths (H band) and with angular resolutions in the range 5-10 milliarcseconds. These nonzero closure phases can only be generated by asymmetric brightness distributions of the target stars or their surroundings. We discuss how these results were obtained, and how they might be interpreted in terms of structures on or near the target stars. We also report measured angular sizes and hypothesize that most Mira stars would show detectable asymmetry if observed with adequate angular resolution.We have measured nonzero closure phases for about 29% of our sample of 56 nearby asymptotic giant branch (AGB) stars, using the three-telescope Infrared Optical Telescope Array (IOTA) interferometer at near-infrared wavelengths (H band) and with angular resolutions in the range 5-10 mas. These nonzero closure phases can only be generated by asymmetric brightness distributions of the target stars or their surroundings. We discuss how these results were obtained and how they might be interpreted in terms of structures on or near the target stars. We also report measured angular sizes and hypothesize that most Mira stars would show detectable asymmetry if observed with adequate angular resolution.

First Results with the IOTA3 Imaging Interferometer: The Spectroscopic Binaries λ Virginis and WR 140

We report the first spatially resolved observations of the spectroscopic binaries λ Vir and WR 140, including the debut of aperture-synthesis imaging with the upgraded three-telescope IOTA interferometer. Using IONIC-3, a new integrated optics beam combiner capable of a precise closure phase measurement, short observations were sufficient to extract the angular separation and orientation of each binary system and the component brightness ratio. Most notably, the underlying binary in the prototypical colliding-wind source WR 140 (WC7 + O4/O5) was found to have a separation of ~13 mas with a position angle of 152°, consistent with previous interpretations of the 2001 dust shell ejection only if the Wolf-Rayet star is fainter than the O star at 1.65 μm. We also highlight λ Vir, whose peculiar stellar properties of the Am star components will permit direct testing of current theories of tidal evolution when the full orbit is determined.

New beam-combination Techniques at IOTA

New beam combination techniques, using two and three telescopes, have been the focus of activity at IOTA during the past two years since our last update. In particular, we have added a third telescope, made closure-phase measurements, demonstrated two- and three-beam combination with integrated optics combiners, demonstrated two-beam combination with an asymmetric coupler, and made simultaneous JHK visibility measurements with an image-plane combiner.

Third telescope project at the IOTA interferometer

The third telescope project to enable phase-closure observations at the IOTA interferometer is well underway, and is anticipated to be completed later this year. For this project, we present the main technical improvements which we have already made or expect to make, including a new VxWorks control system, improved star acquisition cameras, improved siderostat and primary mirror supports, five-axis control of the telescope secondary mirrors, automated control of the long delay line, trihedral retroreflectors, three-beam combination, the PICNIC camera, and fringe packet tracking.

IOTA: Recent Technology and Science ⁄

The Sydney University Stellar Interferometer (SUSI) is a long-baseline optical interferometer operating at an observatory near Narrabri in Australia. SUSI features a 640 m long North-South array with 11 fixed siderostat stations. New science from the Blue (400-500 nm) and from the recently commissioned Red (500-950 nm) fringe detectors will be presented. Recent technological developments, mainly associated with the new Red detection system, encompassing wavefront correction, fringe encoding, wavelength switching and data analysis strategies, are described.Closure-phase science and technology are dominant features of the recent activity at IOTA. Our science projects include imaging several spectroscopic binary stars, imaging YSOs including Herbig AeBe stars, detecting asymmetries in a large sample of Mira stars, and measuring water shells around Miras. Many technology projects were pursued in order to make these science observations possible. These include installation of a third-generation integrated-optics 3-beam combiner (IONIC), completion of the real-time control system software, installation of fringe-packet tracking software, use of narrow sub-H band filters, validation of the phase-closure operation, development of CPLD control of the science camera (PICNIC) and star-tracker camera (LLiST), installation of a new star-tracker camera, expansion of the observing facility, and installation of new semi-automated optical alignment tools.

Early Science with the Large Millimeter Telescope: Observations of Extremely Luminous High-z Sources Identified by Planck

We present 8.5 arcsec resolution 1.1mm continuum imaging and CO spectroscopic redshift measurements of eight extremely bright submillimetre galaxies identified from the Planck and Herschel surveys, taken with the Large Millimeter Telescopes AzTEC and Redshift Search Receiver instruments. We compiled a candidate list of high redshift galaxies by cross-correlating the Planck Surveyor missions highest frequency channel (857 GHz, FWHM = 4.5 arcmin) with the archival Herschel Spectral and Photometric Imaging Receiver (SPIRE) imaging data, and requiring the presence of a unique, single Herschel counterpart within the 150 arcsec search radius of the Planck source positions with 350 micron flux density larger than 100 mJy, excluding known blazars and foreground galaxies. All eight candidate objects observed are detected in 1.1mm continuum by AzTEC bolometer camera, and at least one CO line is detected in all cases with a spectroscopic redshift between 1.3 < z(CO) < 3.3. Their infrared spectral energy distributions mapped using the Herschel and AzTEC photometry are consistent with cold dust emission with characteristic temperature between

A polynomial-based trajectory generator for improved telescope control

T_d

Control systems of the Large Millimeter Telescope

= 43 K and 84 K. With apparent infrared luminosity of up to L(IR) =

The architecture and initial results of the Large Millimeter Telescope control system

3\times10^{14} \mu^{-1} L_\odot