We present wide-field 1.1 mm continuum imaging of the nearby spiral galaxy M 33, conducted with the AzTEC bolometer camera on ASTE. We show that the 1.1 mm flux traces the distribution of dust with
...$T$
$\sim$
20 K. Combined with far-infrared imaging at 160
$\ \mu$
m, we derived the dust temperature distribution out to a galactic radius of
$\sim$
7 kpc with a spatial resolution of
$\sim$
150 pc. Although the 1.1 mm flux was observed predominantly near star-forming regions, we found a smooth radial temperature gradient declining from
$\sim$
20 K to
$\sim$
13 K consistent with recent results from the Herschel satellite. Further comparisons of individual regions show a strong correlation between the cold dust temperature and the
$K_{\rm S}$
band brightness, but not with the ionizing flux. The observed results imply that the dominant heating source of cold dust at few hundred parsec scales is due to non-OB stars, even when associated with star-forming regions.
We present a measurement of the cosmic microwave background lensing potential using 500 deg2 of 150 GHz data from the SPTpol receiver on the South Pole Telescope. The lensing potential is ...reconstructed with signal-to-noise per mode greater than unity at lensing multipoles L 250, using a quadratic estimator on a combination of cosmic microwave background temperature and polarization maps. We report measurements of the lensing potential power spectrum in the multipole range of 100 < L < 2000 from sets of temperature-only (T), polarization-only (POL), and minimum-variance (MV) estimators. We measure the lensing amplitude by taking the ratio of the measured spectrum to the expected spectrum from the best-fit Λ cold dark matter model to the Planck 2015 TT + low P + lensing data set. For the minimum-variance estimator, we find A MV = 0.944 0.058 ( Stat . ) 0.025 ( Sys . ) ; restricting to only polarization data, we find A POL = 0.906 0.090 ( Stat . ) 0.040 ( Sys . ) . Considering statistical uncertainties alone, this is the most precise polarization-only lensing amplitude constraint to date (10.1 ) and is more precise than our temperature-only constraint. We perform null tests and consistency checks and find no evidence for significant contamination.
We present new, wide, and deep images in the 1.1 mm continuum and the
$^{12}$
CO (
$J$
$=$
1–0) emission toward the northern part of the Orion A Giant Molecular Cloud (Orion-A GMC). The 1.1 mm data ...were taken with the AzTEC camera mounted on the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope in Chile, and the
$^{12}$
CO (
$J$
$=$
1–0) data were with the 25 beam receiver (BEARS) on the Nobeyama Radio Observatory (NRO) 45 m telescope in the On-The-Fly (OTF) mode. The present AzTEC observations are the widest (1
$^\circ\!\!\!.$
7
$\times$
2
$^\circ\!\!\!.$
3, corresponding to 12 pc
$\times$
17 pc) and the highest-sensitivity (
$\sim\ $
9 mJy beam
$^{-1}$
) 1.1 mm dust-continuum imaging of the Orion-A GMC with an effective spatial resolution of
$\sim\ $
40
$”$
. The
$^{12}$
CO (
$J$
$=$
1–0) image was taken over the northern 1
$^\circ\!\!\!.$
2
$\times$
1
$^\circ\!\!\!.$
2 (corresponding 9 pc
$\times$
9 pc) area with a sensitivity of 0.93 K in
$T_{\rm MB}$
, a velocity resolution of 1.0 km s
$^{-1}$
, and an effective spatial resolution of 21
$”$
. With these data, together with the MSX 8
$\ \mu$
m, Spitzer 24
$\ \mu$
m, and the 2MASS data, we have investigated the detailed structure and kinematics of molecular gas associated with the Orion-A GMC, and have found evidence for interactions between molecular clouds and the external forces that may trigger star formation. Two types of possible triggers were revealed: (1) Collisions of the diffuse gas on the cloud surface, particularly at the eastern side of the OMC-2/3 region, and (2) Irradiation of UV on the pre-existing filaments and dense molecular cloud cores. Our wide-field and high-sensitivity imaging has provided the first comprehensive view of the potential sites of triggered star formation in the Orion-A GMC.
Abstract
The Simons Observatory is a ground-based cosmic microwave background experiment that consists of three 0.4 m small-aperture telescopes and one 6 m Large Aperture Telescope, located at an ...elevation of 5300 m on Cerro Toco in Chile. The Simons Observatory Large Aperture Telescope Receiver (LATR) is the cryogenic camera that will be coupled to the Large Aperture Telescope. The resulting instrument will produce arcminute-resolution millimeter-wave maps of half the sky with unprecedented precision. The LATR is the largest cryogenic millimeter-wave camera built to date, with a diameter of 2.4 m and a length of 2.6 m. The coldest stage of the camera is cooled to 100 mK, the operating temperature of the bolometric detectors with bands centered around 27, 39, 93, 145, 225, and 280 GHz. Ultimately, the LATR will accommodate 13 40 cm diameter optics tubes, each with three detector wafers and a total of 62,000 detectors. The LATR design must simultaneously maintain the optical alignment of the system, control stray light, provide cryogenic isolation, limit thermal gradients, and minimize the time to cool the system from room temperature to 100 mK. The interplay between these competing factors poses unique challenges. We discuss the trade studies involved with the design, the final optimization, the construction, and ultimate performance of the system.
Abstract
Advances in cosmic microwave background (CMB) science depend on increasing the number of sensitive detectors observing the sky. New instruments deploy large arrays of superconducting ...transition-edge sensor (TES) bolometers tiled densely into ever larger focal planes. High multiplexing factors reduce the thermal loading on the cryogenic receivers and simplify their design. We present the design of focal-plane modules with an order of magnitude higher multiplexing factor than has previously been achieved with TES bolometers. We focus on the novel cold readout component, which employs microwave SQUID multiplexing (
μ
mux). Simons Observatory will use 49 modules containing 70,000 bolometers to make exquisitely sensitive measurements of the CMB. We validate the focal-plane module design, presenting measurements of the readout component with and without a prototype detector array of 1728 polarization-sensitive bolometers coupled to feedhorns. The readout component achieves a 95% yield and a 910 multiplexing factor. The median white noise of each readout channel is 65
pA
/
Hz
. This impacts the projected SO mapping speed by <8%, which is less than is assumed in the sensitivity projections. The results validate the full functionality of the module. We discuss the measured performance in the context of SO science requirements, which are exceeded.
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