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arXiv 1509.01784astro-ph.IMastro-ph.COastro-ph.GA
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Planck/HFI和Herschel/SPIRE在545和857 GHz绝对增益测光定标的比较

Comparison of absolute gain photometric calibration between Planck/HFI and Herschel/SPIRE at 545 and 857 GHz

B. Bertincourt, G. Lagache, B. Schulz, L. Conversi, K. Dassas, P. G. Martin, L. Maurin, A. Abergel, A. Beelen, J-P. Bernard, B. P. Crill, H. Dole, S. Eales, J. … 展开作者

B. Bertincourt, G. Lagache, B. Schulz, L. Conversi, K. Dassas, P. G. Martin, L. Maurin, A. Abergel, A. Beelen, J-P. Bernard, B. P. Crill, H. Dole, S. Eales, J. E. Gudmundsson, E. Lellouch, R. Moreno, O. Perdereau

摘要:

我们比较了普朗克/HFI和赫歇尔/SPIRE仪器的绝对增益测光校准漫发射。HFI和SPIRE的绝对校准都依赖于行星通量测量和与行星大气理论远红外辐射模型的比较。我们在两个重叠的频段,545 GHz / 500 $μ$ m和857 GHz / 350 $μ$ m测量仪器之间的光度交叉校准。所使用的SPIRE地图已在Herschel交互式处理环境(版本12)中处理,HFI数据来自2015年公共数据发布2。在我们的研究中,我们使用了SPIRE观测到的15个大视场,它们总共覆盖了大约120度^[2]。我们仔细地选择了这些区域,以提供高的信噪比,避免SPIRE图中的残留系统性,并跨越宽范围的表面亮度。HFI图经过带通校正,以匹配SPIRE带通观测到的发射。SPIRE图被卷积以匹配HFI光束并放在公共像素网格上。我们在每个领域使用两种方法测量仪器之间的交叉校准相对增益,像素到像素的相关性和角功率谱测量。SPIRE / HFI相对增益在545和857 GHz分别为1.047($\pm$ 0.0069)和1.003($\pm$ 0.0080),表明仪器之间非常好的一致性。这些相对增益偏离单位远小于绝对扩展排放校准的不确定度,HFI和SPIRE的不确定度分别为6.4%和9.5%,但如果可以忽略来自通用校准器模型的不确定度,则偏差与HFI和SPIRE的值1.4%和5.5%相当。在SPIRE的5.5%不确定性中,4%来自有效光束立体角的不确定性,其影响所采用的SPIRE点源到扩展源单位转换因子(简略)

英文摘要:

We compare the absolute gain photometric calibration of the Planck/HFI and Herschel/SPIRE instruments on diffuse emission. The absolute calibration of HFI and SPIRE each relies on planet flux measurements and comparison with theoretical far-infrared emission models of planetary atmospheres. We measure the photometric cross calibration between the instruments at two overlapping bands, 545 GHz / 500 $μ$m and 857 GHz / 350 $μ$m. The SPIRE maps used have been processed in the Herschel Interactive Processing Environment (Version 12) and the HFI data are from the 2015 Public Data Release 2. For our study we used 15 large fields observed with SPIRE, which cover a total of about 120 deg^2. We have selected these fields carefully to provide high signal-to-noise ratio, avoid residual systematics in the SPIRE maps, and span a wide range of surface brightness. The HFI maps are bandpass-corrected to match the emission observed by the SPIRE bandpasses. The SPIRE maps are convolved to match the HFI beam and put on a common pixel grid. We measure the cross-calibration relative gain between the instruments using two methods in each field, pixel-to-pixel correlation and angular power spectrum measurements. The SPIRE / HFI relative gains are 1.047 ($\pm$ 0.0069) and 1.003 ($\pm$ 0.0080) at 545 and 857 GHz, respectively, indicating very good agreement between the instruments. These relative gains deviate from unity by much less than the uncertainty of the absolute extended emission calibration, which is about 6.4% and 9.5% for HFI and SPIRE, respectively, but the deviations are comparable to the values 1.4% and 5.5% for HFI and SPIRE if the uncertainty from models of the common calibrator can be discounted. Of the 5.5% uncertainty for SPIRE, 4% arises from the uncertainty of the effective beam solid angle, which impacts the adopted SPIRE point source to extended source unit conversion factor (Abridged)

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