Wang, Lingyu; Rowan-Robinson, Michael; Yamamura, Issei; Shibai, Hiroshi; Savage, Rich; Oliver, Seb; Thomson, Matthew; Rahman, Nurur; Clements, Dave; Figueredo, Elysandra; Goto, Tomotsugu; Hasegawa, Sunao; Jeong, Woong-Seob; Matsuura, Shuji; Müller, Thomas G.; Nakagawa, Takao; Pearson, Chris P.; Serjeant, Stephen; Shirahata, Mai and White, Glenn J.
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|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1111/j.1365-2966.2008.13292.x|
|Google Scholar:||Look up in Google Scholar|
We present a careful analysis of the point-source detection limit of the AKARI All-Sky Survey in the WIDE-S 90-?m band near the North Ecliptic Pole (NEP). Timeline analysis is used to detect IRAS (Infrared Astronomy Satellite) sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90-?m flux of a source. Combined with a robust noise measurement, the point-source flux detection limit at signal-to-noise ratio (S/N) > 5 for a single detector row is 1.1 ± 0.1 Jy which corresponds to a point-source detection limit of the survey of ?0.4 Jy. Wavelet transform offers a multiscale representation of the Time Series Data (tsd). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4? can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non-IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non-IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.
|Item Type:||Journal Article|
|Copyright Holders:||2008 The Authors|
|Keywords:||methods: data analysis;surveys;infrared: galaxies;infrared: ISM|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Colin Smith|
|Date Deposited:||30 Nov 2010 20:14|
|Last Modified:||16 Jan 2016 06:25|
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