Confusion of extragalactic sources in the far infrared: a baseline assessment of the performance of PRIMAger in intensity and polarization
arxiv(2024)
摘要
Because of their limited angular resolution, far-infrared telescopes are
usually affected by confusion phenomenon. Since several galaxies can be located
in the same instrumental beam, only the brightest objects emerge from the
fluctuations caused by fainter sources. The probe far-infrared mission for
astrophysics imager (PRIMAger) will observe the mid- and far-infrared (25-235
μm) sky both in intensity and polarization. We aim to provide predictions
of the confusion level and its consequences for future surveys. We produced
simulated PRIMAger maps affected only by the confusion noise using the
simulated infrared extragalactic sky (SIDES) semi-empirical simulation. We then
estimated the confusion limit in these maps and extracted the sources using a
basic blind extractor. By comparing the input galaxy catalog and the extracted
source catalog, we derived various performance metrics as completeness, purity,
and the accuracy of various measurements. In intensity, we predict that the
confusion limit increases rapidly with increasing wavelength. The confusion
limit in polarization is more than 100x lower. The measured flux density is
dominated by the brightest galaxy in the beam, but other objects also
contribute at longer wavelength ( 30
clustering has a mild impact on confusion in intensity (up to 25
negligible in polarization. In intensity, a basic blind extraction will be
sufficient to detect galaxies at the knee of the luminosity function up to z 3
and 10^11 M_⊙ main-sequence galaxies up to z 5. In polarization for
the baseline sensitivity, we expect 8 000 detections up to z=2.5 opening a
totally new window on the high-z dust polarization. Finally, we show that
intensity surveys at short wavelength and polarization surveys at long
wavelength tend to reach confusion at similar depth. There is thus a strong
synergy.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要