Mimicking the observation of an exoplanet transit

DATA from a NIRSpec observation of a BRIGHT SOURCE ACQUIRED during ISIM-CV3 testing

There are a number of instrumental effects and calibration uncertainties that can increase the actual noise level of a NIRSpec observation of an exoplanet transit above the noise floor of the instrument as determined by the detector read noise and the signal shot noise. To assess the stability of our system and the impact of systematic effects for this instrument mode we performed a dedicated test during ISIM-CV3, the cryo-vacuum campaign of the JWST Integrated Science Instrument Module (ISIM), that took place at Goddard Space Flight Center during the winter 2015-2016.

We used NIRSpec PRISM/CLEAR configuratio to acquire a 3-hour long NIRSpec exposure of a bright source.

A preliminary assessment of the data quality and NIRSpec performance during this test is provided in this Performance Report.

The data from the test are available for download from our FTP server below (anonymous login, please use a secure FTP client):

​​​​​​​ftp.cosmos.esa.int:/pub/jwstlib/ReleasedCV3dataTimeSeries