A few weeks after we integrated the first near infrared camera at the Subaru telescope, we carried out the engineering observation from 20 April to 2 May 2023.
The observation took about two weeks. Over that long period, we conducted numerous tests and development. The most important achievement was that we succeeded in taking on-sky data using the near infrared camera!
The above figure shows about 1200 spectra of the night sky using three cameras (blue, red, and near-infrared) of the first spectrograph and two cameras (blue and red) of the second spectrograph. The figure shows that the sky is very bright in the near-infrared, full of sky emission lines. Since the light of distant galaxies is very faint, it is critical to remove the sky lined from the data to study the objects. The real sky spectra with Subaru Telescope and PFS are quite important for software development. We also took calibration data to characterize the instrument in order to improve software. Besides, we obtained spectra of stars and galaxies to validate the instruments.
In addition, we also carried out tests to move the fibers more accurately, and to verify the guiding function. Thanks to the long observation period, we improved accuracy of the fiber movement by providing the feedback from observation.
The team are analyzing the data and discussing the result for the next run in July 2023.