Observations Of Rotating Radio Transients With The First Station Of The Long Wavelength Array

Rotating Radio Transients (RRATs) are a subclass of pulsars first identified in 2006 that are detected only in searches for single pulses and not through their time averaged emission. Here, we present the results of observations of 19 RRATs using the first station of the Long Wavelength Array (LWA1) at frequencies between 30 MHz and 88 MHz. The RRATs observed here were first detected in higher frequency pulsar surveys. Of the 19 RRATs observed, 2 sources were detected and their dispersion measures, periods, pulse profiles, and flux densities are reported and compared to previous higher frequency measurements. We find a low detection rate (11%), which could be a combination of the lower sensitivity of LWA1 compared to the higher frequency telescopes, and the result of scattering by the interstellar medium or a spectral turnover. Taylor, G B; Stovall, K; McCrackan, M; McLaughlin, M A; Miller, R; Karako-Argaman, C; Dowell, J; Schinzel, F

Observations Of Rotating Radio Transients With The First Station Of The Long Wavelength Array

Rotating Radio Transients (RRATs) are a subclass of pulsars first identified in 2006 that are detected only in searches for single pulses and not through their time averaged emission. Here, we present the results of observations of 19 RRATs using the first station of the Long Wavelength Array (LWA1) at frequencies between 30 MHz and 88 MHz. The RRATs observed here were first detected in higher frequency pulsar surveys. Of the 19 RRATs observed, 2 sources were detected and their dispersion measures, periods, pulse profiles, and flux densities are reported and compared to previous higher frequency measurements. We find a low detection rate (11%), which could be a combination of the lower sensitivity of LWA1 compared to the higher frequency telescopes, and the result of scattering by the interstellar medium or a spectral turnover. Taylor, G B; Stovall, K; McCrackan, M; McLaughlin, M A; Miller, R; Karako-Argaman, C; Dowell, J; Schinzel, F

Early science with the Large Millimeter Telescope: a 1.1 mm AzTEC survey of red-<i>Herschel</i> dusty star-forming galaxies

We present Large Millimeter Telescope (LMT)/AzTEC 1.1 mm observations of ∼100 luminous high-redshift dusty star-forming galaxy candidates from the ∼600 sq.deg Herschel-ATLAS survey, selected on the basis of their SPIRE red far-infrared colours and with S500μm=35−80 mJy. With an effective θFWHM ≈ 9.5arcsec angular resolution, our observations reveal that at least 9 per cent of the targets break into multiple systems with signal-to-noise ratio ≥4 members. The fraction of multiple systems increases to ∼23 per cent (or more) if some non-detected targets are considered multiples, as suggested by the data. Combining the new AzTEC and deblended Herschel photometry, we derive photometric redshifts, infrared luminosities, and star formation rates. While the median redshifts of the multiple and single systems are similar (zmed ≈ 3.6), the redshift distribution of the latter is skewed towards higher redshifts. Of the AzTEC sources, ∼85 per cent lie at zphot > 3 while ∼33 per cent are at zphot > 4. This corresponds to a lower limit on the space density of ultrared sources at 4 −7Mpc−3 with a contribution to the obscured star formation of ≳8×10−4M⊙yr−1Mpc−3⁠. Some of the multiple systems have members with photometric redshifts consistent among them suggesting possible physical associations. Given their angular separations, these systems are most likely galaxy over-densities and/or early-stage pre-coalescence mergers. Finally, we present 3 mm LMT/RSR spectroscopic redshifts of six red-Herschel galaxies at zspec = 3.85−6.03, two of them (at z ∼ 4.7) representing new redshift confirmations. Here, we release the AzTEC and deblended Herschel photometry as well as catalogues of the most promising interacting systems and z > 4 galaxies

The optical design and performance of TolTEC: a millimeter-wave imaging polarimeter

TolTEC is an imaging polarimeter that will be mounted on the 50m diameter Large Millimeter Telescope (LMT) in Mexico. This camera simultaneously images the focal plane at three wavebands centered at 1.1, 1.4, and 2.0mm. TolTEC combines polarization-sensitive Kinetic Inductance Detectors (KIDs) with the LMT to produce 5-10 arcmin resolution maps of the sky in both total intensity and polarization. The light from the telescope is coupled to the TolTEC instrument using three room temperature mirrors. Before entering the cryostat, the light passes through a rapid-spinning achromatic half-wave plate, and once inside it passes through a 1 K Lyot stop that controls the telescope illumination. Inside the cryostat, a series of aluminum mirrors, silicon lenses, and dichroic filters split the light into three wavelength bands and direct each band to a different detector array. We will describe the design, and performance of the optics before installation at the telescope

The TolTEC camera: polarimetric commissioning and performance of the continuously rotating half-wave plate

An ambient-temperature Continuously Rotating Half-Wave Plate (CRHWP) modulates the input polarization signal thereby enabling removal of low-frequency (1/f) noise from polarized flux measurements. This 1/f noise arises from atmospheric turbulence as well as from effects intrinsic to certain detectors. Here, we describe the design and performance of the half wave plate rotator and achromatic half-wave plate for the the new imaging polarimeter, TolTEC. These components are mounted in front of the cryostat window and operate at ambient temperature. The Half-Wave Plate Rotator (HWPR) spins the half-wave plate at 2 revolutions per second. The rotation mechanism consists of nine air bearings to provide low-friction motion and a frameless torque motor to directly drive rotation. The orientation of the rotor and half-wave plate are recorded using a high-precision optical encoder. We review the experimental requirements and technical design of the rotator as well as the associated electronics, pneumatics, and software

The TolTEC camera: an overview of the instrument and in-lab testing results

TolTEC is a three-band imaging polarimeter for the Large Millimeter Telescope. Simultaneously observing with passbands at 1.1mm, 1.4mm and 2.0mm, TolTEC has diffraction-limited beams with FWHM of 5, 7, and 11 arcsec, respectively. Over the coming decade, TolTEC will perform a combination of PI-led and Open-access Legacy Survey projects. Herein we provide an overview of the instrument and give the first quantitative measures of its performance in the lab prior to shipping to the telescope in 2021