Planning JWST NIRSpec MSA spectroscopy using NIRCam pre-images
Planning JWST NIRSpec MSA spectroscopy using NIRCam pre-images
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使用 NIRCam 前像规划 JWST NIRSpec MSA 光谱
DOI：
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发表时间：
2016
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通讯作者：
M. Peña
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作者：
T. Beck;L. Úbeda;S. Kassin;K. Gilbert;D. Karakla;I. Reid;W. Blair;C. Keyes;D. Soderblom;M. Peña
近红外光谱仪(NIRSpec)是詹姆斯·韦伯太空望远镜(JWST)1-5微米的主力光谱仪。NIRSpec的一种展示观测模式是使用微快门阵列(MSA)的多对象光谱，该阵列由25万个微小的可配置快门组成，这些快门的值为0。‘’20×0。‘’46码。NIRSpec MSA快门可以在相邻的行中打开，以便在感兴趣的主要科学目标上创建灵活且可定位的光谱分析狭缝。由于快门宽度非常小，NIRSpec MSA光谱数据质量将大大受益于对计划中的科学源位置的准确天文测量知识。哈勃太空望远镜(HST)获取的图像具有最佳的相对天体测量精度，可用于规划5-10毫角秒(Ma)的NIRSpec观测。然而，一些感兴趣的科学领域可能没有HST图像，银河场可能在5 Ma或更大的水平上有适度的自行，而有HST的河外图像在NIRSpec波长超过2微米时可能没有足够的源信息。因此，最佳的NIRSpec光谱计划可能需要使用JWST上的近红外相机(NIRCam)进行预成像观测，以准确地确定震源位置，以便与NIRSpec MSA对准。我们描述了在相同的JWST观测周期内为NIRSpec MSA光谱规划获取JWST NIRCam前像观测的操作原理和程序考虑因素。
The Near-Infrared Spectrograph (NIRSpec) is the work-horse spectrograph at 1-5microns for the James Webb Space Telescope (JWST). A showcase observing mode of NIRSpec is the multi-object spectroscopy with the Micro-Shutter Arrays (MSAs), which consist of a quarter million tiny configurable shutters that are 0. ′′20×0. ′′46 in size. The NIRSpec MSA shutters can be opened in adjacent rows to create flexible and positionable spectroscopy slits on prime science targets of interest. Because of the very small shutter width, the NIRSpec MSA spectral data quality will benefit significantly from accurate astrometric knowledge of the positions of planned science sources. Images acquired with the Hubble Space Telescope (HST) have the optimal relative astrometric accuracy for planning NIRSpec observations of 5-10 milli-arcseconds (mas). However, some science fields of interest might have no HST images, galactic fields can have moderate proper motions at the 5mas level or greater, and extragalactic images with HST may have inadequate source information at NIRSpec wavelengths beyond 2 microns. Thus, optimal NIRSpec spectroscopy planning may require pre-imaging observations with the Near-Infrared Camera (NIRCam) on JWST to accurately establish source positions for alignment with the NIRSpec MSAs. We describe operational philosophies and programmatic considerations for acquiring JWST NIRCam pre-image observations for NIRSpec MSA spectroscopic planning within the same JWST observing Cycle.