论文标题
Spitzer IRAC通量与HST CalSpec相比
How do Spitzer IRAC Fluxes Compare to HST CALSPEC
论文作者
论文摘要
物理单位中恒星亮度的准确表对于多种科学努力至关重要。磁通标准的HST/CALSPEC数据库包含许多在0.115--1 \ micron \范围内具有光谱覆盖率的恒星，其中一些延伸到1.7或2.5 \ micron的较长波长。建模到32 \ micron \的通量分布以校准JWST，以补充较短的波长HST测量值。了解IRAC观察和CalSpec模型之间的差异对于使用包括JWST在内的多种仪器的IR通量的科学很重要。在3.6--8 \ micron \时，Spitzer IRAC光度法的绝对通量与CalSpec合成光度法吻合至1 \％，对于三个素数HST标准G191B2B，GD153和GD71。对于一组17--22 A-Star标准，平均IRAC差异从协议为3.6 \ micron \升至3.4 $ \ pm $ 0.1 \％\％\％\％\％\％\％\％\％\％\％\ micron。对于较小的G-Stars，IRAC光度法的平均值低于CalSpec的平均值3.7 $ \ pm $ $ 0.3 \％\％\％，而一个G-Star P330E与IRAC/CALSPEC比率的A-Star集合一致。
An accurate tabulation of stellar brightness in physical units is essential for a multitude of scientific endeavors. The HST/CALSPEC database of flux standards contains many stars with spectral coverage in the 0.115--1 \micron\ range with some extensions to longer wavelengths of 1.7 or 2.5 \micron. Modeled flux distributions to 32 \micron\ for calibration of JWST complement the shorter wavelength HST measurements. Understanding the differences between IRAC observations and CALSPEC models is important for science that uses IR fluxes from multiple instruments, including JWST. The absolute flux of Spitzer IRAC photometry at 3.6--8 \micron\ agrees with CALSPEC synthetic photometry to 1\% for the three prime HST standards G191B2B, GD153, and GD71. For a set of 17--22 A-star standards, the average IRAC difference rises from agreement at 3.6 \micron\ to 3.4 $\pm$0.1\% brighter than CALSPEC at 8 \micron. For a smaller set of G-stars, the average of the IRAC photometry falls below CALSPEC by as much as 3.7 $\pm$0.3\% for IRAC1, while one G-star, P330E, is consistent with the A-star ensemble of IRAC/CALSPEC ratios.
