Title: The ISOPHOT 170 Micron Serendipity Sky Survey : A Plea to FIRST
Abstract: The ISOPHOT Serendipity Survey utilized the slew time between ISO’s pointed observations with strip scanningmeasurements of the sky in the far-infrared (FIR) at 170µm. The integral 170µm fluxes for compact sources derived from the slews are put on an absolute flux level by usinga number of g alaxies as calibrator sources observed with ISOPHOT’s photometric mappingmode, supplemented by Serendipity Survey observations of two planets and two asteroids with available model fluxes. A first group of 115 well-observed sources with a high signalto-noise ratio in all four detector pixels havinga g alaxy association were extracted from the slew data with low (I100µm ≤ 15 MJy/sr) cirrus background. For all but a few galaxies, the 170µm fluxes are determined for the first time, which represents a significant increase in the number of galaxies with measured FIR fluxes beyond the IRAS 100µm limit. The large fraction of sources with a high F170µm/F100µm flux ratio indicates that a very cold (T < 20 K) dust component is present in many galaxies. The typical mass of the coldest dust component is MDust =1 0 7.5 ±0.5 M� , a factor 2 – 10 larger than that derived from IRAS fluxes alone. As a consequence, the gas-to-dust ratios are much closer to the canonical value for the Milky Way. A similar Serendipity Survey with FIRST has the prospects of deliveringFIR data with a much hig her angular resolution (PACS) or at longer wavelengths (SPIRE) than ISOPHOT, thereby providingeither crucial information for the identification of compact sources in confused regions or extending the spectral coverage for a large number of sources and findingrare classes of very cold FIR emitters.
Publication Year: 2001
Publication Date: 2001-07-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot