Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. I. The Stellar Calibrator Sample and the 24 μm Calibration
Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. I. The Stellar Calibrator Sample and the 24 μm Calibration
复制标题
DOI：
10.1086/521881
复制
发表时间：
2007-04
影响因子：
3.5
通讯作者：
C. Engelbracht;M. Blaylock;Kate Y. L. Su;Jeonghee Rho;G. Rieke;J. Muzerolle;D. Padgett;D. Hines;K. D. Gordon;Dario Fadda;A. Noriega-Crespo;D. Kelly;W. Latter;J. Hinz;K. Misselt;J. Morrison;J. Stansberry;D. Shupe;S. Stolovy;W. Wheaton;E. Young;G. Neugebauer;Stefanie Wachter;P. Pérez-González;P. Pérez-González;D. Frayer;F. Marleau
中科院分区：
文献类型：
--
作者：
C. Engelbracht;M. Blaylock;Kate Y. L. Su;Jeonghee Rho;G. Rieke;J. Muzerolle;D. Padgett;D. Hines;K. D. Gordon;Dario Fadda;A. Noriega-Crespo;D. Kelly;W. Latter;J. Hinz;K. Misselt;J. Morrison;J. Stansberry;D. Shupe;S. Stolovy;W. Wheaton;E. Young;G. Neugebauer;Stefanie Wachter;P. Pérez-González;P. Pérez-González;D. Frayer;F. Marleau
本文介绍了斯皮策多波段成像光度计（MIPS） 24 μm通道的恒星校准器样品和仪器到物理单位的转换。主标定星为A星，标定因子为4.54 × 10-2 MJy sr−1 (DN s−1)−1，标称不确定度为2%。我们讨论了达到这种精度所需的数据简化程序；在没有这些步骤的情况下，使用斯皮策科学中心的自动化管道获得的校准因子降低1.6%±0.6%。我们扩展了这项工作，预测了238颗恒星样本的24 μm通量密度，覆盖了更大范围的通量密度和光谱类型。我们在24 μm波段对141颗恒星进行了348次测量。该样品覆盖了24 μm通量密度的约460因子，从8.6 Jy到4.0 Jy。我们表明，在该范围内，相对于目标通量和背景电平，校准是线性的。校准是基于使用3秒曝光进行的观测；初步分析表明，10秒和30秒曝光时，校正因子可能分别降低1%和2%。我们还证明了校准非常稳定：在任务过程中，我们的常规校准器HD 159330的重复测量显示均方根散射仅为0.4%。最后，我们证明了点扩散函数（PSF）可以很好地测量，并允许我们准确校准扩展源；红外天文卫星（IRAS）和MIPS对附近星系样本的测量在不确定度内是相同的。
We present the stellar calibrator sample and the conversion from instrumental to physical units for the 24 μm channel of the Multiband Imaging Photometer for Spitzer (MIPS). The primary calibrators are A stars, and the calibration factor based on those stars is 4.54 × 10-2 MJy sr−1 (DN s−1)−1, with a nominal uncertainty of 2%. We discuss the data reduction procedures required to attain this accuracy; without these procedures, the calibration factor obtained using the automated pipeline at the Spitzer Science Center is 1.6% ± 0.6% lower. We extend this work to predict 24 μm flux densities for a sample of 238 stars that covers a larger range of flux densities and spectral types. We present a total of 348 measurements of 141 stars at 24 μm. This sample covers a factor of ∼460 in 24 μm flux density, from 8.6 mJy up to 4.0 Jy. We show that the calibration is linear over that range with respect to target flux and background level. The calibration is based on observations made using 3 s exposures; a preliminary analysis shows that the calibration factor may be 1% and 2% lower for 10 and 30 s exposures, respectively. We also demonstrate that the calibration is very stable: over the course of the mission, repeated measurements of our routine calibrator, HD 159330, show a rms scatter of only 0.4%. Finally, we show that the point‐spread function (PSF) is well measured and allows us to calibrate extended sources accurately; Infrared Astronomy Satellite (IRAS) and MIPS measurements of a sample of nearby galaxies are identical within the uncertainties.