[Review] Unesco in Southeast Asia: World Heritage Sites in Comparative Perspective

Book review of Unesco in Southeast Asia: World Heritage Sites in Comparative Perspective edited by Victor T. King, Nordic Institute of Asian Studies Press 2016

Design and performance of feedhorn-coupled bolometer arrays for SPIRE

This paper reviews the design, modeling, and testing of feedhorn arrays coupled to bolometric detector arrays being developed for the ESA Herschel Space Observatory's SPIRE instrument. SPIRE will incorporate five arrays of silicon nitride micromesh bolometers, in three broadband photometers and two Fourier-Transform spectrometers covering 200-700 μm, with a total of 326 feedhorn-coupled bolometers. The precision feedhorn arrays are formed by close-packing individually fabricated conical feedhorns, which terminate in waveguides and integrating cavities. The detector array is efficiently packaged by mounting it between a metallized silicon backshort array and the feedhorn array, which encloses the bolometers in precisely tuned integrating cavities. The absorption efficiency, bandwidth, and cross talk were first investigated with numerical simulations of the electromagnetic fields, and then measured for prototype arrays in a test facility. This discussion describes the design goals, simulations, fabrication, and measurements of optical efficiencies, spectral properties, beam shapes, and cross talk between bolometers

Turbulent viscosity in clumpy accretion disks II supernova driven turbulence in the Galaxy

An analytical model for a turbulent clumpy gas disk is presented where turbulence is maintained by the energy input due to supernovae. Expressions for the disk parameters, global filling factors, molecular fractions, and star formation rates are given as functions of the Toomre parameter $Q$, the ratio between the cloud size and the turbulent driving length scale $\delta$, the mass accretion rate within the disk $\dot{M}$, the constant of molecule formation $\alpha$, the disk radius, the angular velocity, and its radial derivative. Two different cases are investigated: a dominating stellar disk and a self-gravitating gas disk in $z$ direction. The turbulent driving wavelength is determined in a first approach by energy flux conservation, i.e. the supernovae energy input is transported by turbulence to smaller scales where it is dissipated. The results are compared to those of a fully gravitational model. For Q=1 and $\delta=1$ both models are consistent with each other. In a second approach the driving length scale is directly determined by the size of supernovae remnants. Both models are applied to the Galaxy and can reproduce its integrated and local gas properties. The influence of thermal and magnetic pressure on the disk structure is investigated. We infer $Q \sim 1$ and $\dot{M} \sim 0.05 - 0.1 M_{\odot} yr ^{-1}$ for the Galaxy.Comment: 15 pages with 10 figures. Accepted for publication in A&

Real‐time B‐mode ultrasound quality control test procedures. Report of AAPM Ultrasound Task Group No. 1

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134873/1/mp8404.pd

The dark matter halo shape of edge-on disk galaxies - II. Modelling the HI observations: methods

This is the second paper of a series in which we attempt to put constraints on the flattening of dark halos in disk galaxies. For this purpose, we observe the HI in edge-on galaxies, where it is in principle possible to measure the force field in the halo vertically and radially from gas layer flaring and rotation curve decomposition respectively. To calculate the force fields, we need to analyse the observed XV diagrams to accurately measure all three functions that describe the planar kinematics and distribution of a galaxy: the radial HI surface density, the rotation curve and the HI velocity dispersion. In this paper, we discuss the improvements and limitations of the methods previously used to measure these HI properties. We extend the constant velocity dispersion method to include determination of the HI velocity dispersion as a function of galactocentric radius and perform extensive tests on the quality of the fits. We will apply this 'radial decomposition XV modelling method' to our HI observations of 8 HI-rich, late-type, edge-on galaxies in the third paper of this series.Comment: Accepted for publication by Astronomy & Astrophysics. For a higher resolution version see http://www.astro.rug.nl/~vdkruit/jea3/homepage/12566.pd

The star-forming content of the W3 giant molecular cloud

We have surveyed a ~0.9-square-degree area of the W3 giant molecular cloud and star-forming region in the 850-micron continuum, using the SCUBA bolometer array on the James Clerk Maxwell Telescope. A complete sample of 316 dense clumps was detected with a mass range from around 13 to 2500 Msun. Part of the W3 GMC is subject to an interaction with the HII region and fast stellar winds generated by the nearby W4 OB association. We find that the fraction of total gas mass in dense, 850-micron traced structures is significantly altered by this interaction, being around 5% to 13% in the undisturbed cloud but ~25 - 37% in the feedback-affected region. The mass distribution in the detected clump sample depends somewhat on assumptions of dust temperature and is not a simple, single power law but contains significant structure at intermediate masses. This structure is likely to be due to crowding of sources near or below the spatial resolution of the observations. There is little evidence of any difference between the index of the high-mass end of the clump mass function in the compressed region and in the unaffected cloud. The consequences of these results are discussed in terms of current models of triggered star formation.Comment: 13 pages, 8 figures, 1 table (full source table available on request). Accepted for publication in Monthly Notices of the Royal Astronomical Society (Main Journal

Design and performance of feedhorn-coupled bolometer arrays for SPIRE

This paper reviews the design, modeling, and testing of feedhorn arrays coupled to bolometric detector arrays being developed for the ESA Herschel Space Observatory's SPIRE instrument. SPIRE will incorporate five arrays of silicon nitride micromesh bolometers, in three broadband photometers and two Fourier-Transform spectrometers covering 200-700 μm, with a total of 326 feedhorn-coupled bolometers. The precision feedhorn arrays are formed by close-packing individually fabricated conical feedhorns, which terminate in waveguides and integrating cavities. The detector array is efficiently packaged by mounting it between a metallized silicon backshort array and the feedhorn array, which encloses the bolometers in precisely tuned integrating cavities. The absorption efficiency, bandwidth, and cross talk were first investigated with numerical simulations of the electromagnetic fields, and then measured for prototype arrays in a test facility. This discussion describes the design goals, simulations, fabrication, and measurements of optical efficiencies, spectral properties, beam shapes, and cross talk between bolometers

On the dust abundance gradients in late-type galaxies: I. Effects of destruction and growth of dust in the interstellar medium

We present basic theoretical constraints on the effects of destruction by supernovae (SNe) and growth of dust grains in the interstellar medium (ISM) on the radial distribution of dust in late-type galaxies. The radial gradient of the dust-to-metals ratio is shown to be essentially flat (zero) if interstellar dust is not destroyed by SN shock waves and all dust is produced in stars. If there is net dust destruction by SN shock waves, the dust-to-metals gradient is flatter than or equal to the metallicity gradient (assuming the gradients have the same sign). Similarly, if there is net dust growth in the ISM, then the dust-to-metals gradient is steeper than or equal to the metallicity gradient. The latter result implies that if dust gradients are steeper than metallicity gradients, i.e., the dust-to-metals gradients are not flat, then it is unlikely dust destruction by SN shock waves is an efficient process, while dust growth must be a significant mechanism for dust production. Moreover, we conclude that dust-to-metals gradients can be used as a diagnostic for interstellar dust growth in galaxy discs, where a negative slope indicates dust growth.Comment: 12 pages, 4 figures. Accepted for publication in MNRA