Showing papers by "Jason Glenn published in 2007"
TL;DR: In this paper, a 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory was conducted, detecting 122, 44, and 35 cores, respectively.
Abstract: We have undertaken an unprecedentedly large 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 deg2 in Perseus (Enoch and coworkers), 10.8 deg^2 in Ophiuchus (Young and coworkers), and 1.5 deg2 in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (α = 2.1 ± 0.1 and 2.1 ± 0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (α = 1.6 ± 0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with AV ~> 8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
210 citations
Cardiff University1, Jet Propulsion Laboratory2, University of Padua3, University of Colorado Boulder4, Rutherford Appleton Laboratory5, University of Lethbridge6, University of Sussex7, Spanish National Research Council8, Imperial College London9, Institut d'Astrophysique de Paris10, UK Astronomy Technology Centre11
TL;DR: SPIRE, the Spectral and Photometric Imaging Receiver, is one of three instruments to fly on the European Space Agency's Herschel Space Observatory as discussed by the authors, which contains a three-band imaging photometer operating at 250, 350 and 500 μm and an imaging Fourier transform spectrometer covering 194-672 μm.
33 citations
TL;DR: In this article, the authors performed a 1.1 millimeter continuum survey of three nearby star forming clouds using Bolocam at the Caltech Submillimeter Observatory, detecting 122, 44, and 35 cores.
Abstract: We have undertaken an unprecedentedly large 1.1 millimeter continuum survey of three nearby star forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 sq. deg in Perseus (Paper I), 10.8 sq. deg in Ophiuchus (Paper II), and 1.5 sq. deg in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (alpha=2.1+/-0.1 and alpha=2.1+/-0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (alpha=1.6+/-0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star-formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with Av>8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
16 citations
01 Dec 2007
1 citations
01 Jan 2007
TL;DR: AzTEC as mentioned in this paper is a large-format bolometer array camera developed at the University of Massachusetts, Amherst, and will serve as one of the first facility instruments of the Large Millimeter Telescope (LMT).
Abstract: AzTEC is a large-format bolometer array camera developed at the University of Massachusetts, Amherst, and will serve as one of the first facility instruments of the Large Millimeter Telescope (LMT). AzTEC’s detector array is comprised of 144 silicon nitride micromesh bolometers with a bandpass defined through a series of changeable filters and coupling optics. AzTEC was recently commissioned at 1.1 millimeters on the James Clerk Maxwell Telescope (JCMT) and successfully completed its first science-grade observing run in the winter 2005/2006. We experienced excellent performance throughout the run, with a median raw per-pixel sensitivity to point-like sources of 14 mJy √s. We present the instrument design and achieved specifications, as well as the nature of AzTEC data and its format. We also discuss calibration and observing strategies for using the AzTEC instrument.
1 citations