Showing papers by "Mark Halpern published in 2002"
TL;DR: In this article, Monte Carlo simulations of ground-based, balloon-borne and satellite sub-millimetre surveys were used to derive photometric redshifts with an rms accuracy of ± 0.4 over the range 0 3 × 10 12 L� ) with an accuracy of ∼20 per cent.
Abstract: Future extragalactic submillimetre and millimetre surveys have the potential to provide a sensitive census of the level of obscured star formation in galaxies at all redshifts. While in general there is good agreement between the source counts from existing Submillimetre Common User Bolometer Array (SCUBA; 850-µm) and Max Planck Millimetre Bolometer Array (MAMBO; 1.25-mm) surveys of different depths and areas, it remains difficult to determine the redshift distribution and bolometric luminosities of the submillimetre and millimetre galaxy population. This is principally due to the ambiguity in identifying an individual submillimetre source with its optical, IR or radio counterpart which, in turn, prevents a confident measurement of the spectroscopic redshift. Additionally, the lack of data measuring the rest-frame FIR spectral peak of the submillimetre galaxies gives rise to poor constraints on their rest-frame FIR luminosities and star formation rates. In this paper we describe Monte Carlo simulations of ground-based, balloon-borne and satellite submillimetre surveys that demonstrate how the restframe FIR‐submillimetre spectral energy distributions (250‐850 µm) can be used to derive photometric redshifts with an rms accuracy of ±0.4 over the range 0 3 × 10 12 L� ) with an accuracy of ∼20 per cent.
65 citations
TL;DR: In this article, the authors used the 850-μm SCUBA camera on the JCMT and a scanning technique different from other sub-mm surveys to obtain a 125 arcmin 2 map centred on the Hubble Deep Field.
Abstract: Using the 850-μm SCUBA camera on the JCMT and a scanning technique different from other sub-mm surveys, we have obtained a 125 arcmin 2 map centred on the Hubble Deep Field. The 1σ sensitivity to point sources is roughly 3mJy and thus our map probes the brighter end of the sub-mm source counts. We find six sources with a flux greater than about 12 mJy (>4σ) and, after a careful accounting of incompleteness and flux bias, estimate the integrated density of bright sources N(>12 mJy) = 164 + 7 7 - 5 8 deg - 2 (68 per cent confidence bounds).
45 citations
08 Mar 2002
TL;DR: The Balloon-borne Large Aperture Sub-millimeter Telescope (BLAST) as mentioned in this paper is the first large-scale, long-duration balloon-borne sub-mmimeter telescope.
Abstract: The Balloon-borne Large Aperture Sub-millimeter Telescope (BLAST) incorporates a two meter primary mirror with large-format bolometer arrays consisting of 149, 88, and 43 elements operating at 250, 350 and 500 µm, respectively. The combination of the dramatically increased atmospheric transmission at balloon altitudes and the extended observing time (10–20 days) afforded by a long duration balloon flight will enable the first sensitive, large-area (10 deg2) sub-mm surveys at these wavelengths. These surveys will address some of the most important galactic and cosmological questions regarding the formation and evolution of stars, galaxies, and clusters as well as the source(s) of the cosmic infrared background. The BLAST focal plane will consist of arrays of silicon nitride micromesh, "spider-web" bolometric detectors operating at 300 mK coupled to 2 f feedhorn arrays. The first overnight test flight of BLAST is scheduled for autumn of 2002, and the first long duration balloon flight is scheduled to be from McMurdo, Antarctica in 2003–2004.
7 citations
01 Mar 2002
TL;DR: BLAST as mentioned in this paper is a balloon-borne Large Aperture Sub-millimeter Telescope with three bolometer arrays operating at 250, 350, and 500 pm, with 149, 88, and 43 detections respectively.
Abstract: BLAST the Balloon-borne Large Aperture Sub-millimeter Telescope, will have three bolometer arrays operating at 250, 350, and 500 pm, with 149, 88, and 43 detectoi-s
respectively. The arrays will be cooled to 300 rnK so that the receiver's noise (NEFD) will be dominated by photon shot noise and atmospheric emission. Because of the high (35 km) altitude of balloon observations, atmospheric noise will be low and we expect NEFDs less than 241 mJy/H:1 2 in all channels. A 2.0 m diameter spherical mirror will give diffraction limited resolutions of 30, 41, and 59" respectively.
The first test flight, planned for early 2003, will last 6-24 hours across North America. Long-duration balloon flights from Antarctica will begin in late 2003 and will last 14 days. BLAST will yield data on astronomical problems as close as nearby stars and as far away as the beginnings of the Universe.
1 citations
19 Sep 2002
TL;DR: In this article, the spectral signature of dimers which will likely appear in far-infrared spectra of Titan was obtained by the Composite Infrared Spectrometer (CIS) onboard the Cassini spacecraft.
Abstract: Submillimeter absorption spectra of nitrogen, nitrogen-argon mixtures, and methane have been measured using temperatures and pressures near to those found in the atmospheres of Titan and Saturn. The experiments show the spectral signature of dimers which will likely appear in far-infrared spectra of Titan that will be obtained by the Composite Infrared Spectrometer (CIS) onboard the Cassini spacecraft. The recent CIRS spectrum of Jupiter shows far-infrared spectral lines of methane and the corresponding lines are observed in the laboratory. We are extending this work to lower frequencies using a new differential Michelson interferometer that operates over the frequency region 3-30 1/cm..
1 citations