Names and Terms of IRD/REACH data

For information about each instrument, visit IRD official page or REACH official page.

Terms Related to IRD/REACH

• band: Y/J-band detector or H-band detector

  • The origin of the detector images below is at the lower left.

  • If the images in your data set are rotated in different orientation, use the rotate and/or inverse instance in Stream2D.

IRD Detectors

Detector Image	Note
	Y/J-band 51 orders x 2 fibers = 102 apertures
	H-band 21 orders x 2 fibers = 42 apertures

• mmf: Multi Mode Fiber used for IRD

  • mmf1 (or comb-fiber): A fiber to inject the light from Laser Frequency Comb (LFC) for simultaneous wavelength reference.

  • mmf2 (or star-fiber): A fiber to inject the light of a star.

• smf: Single Mode Fiber used for REACH

Naming Conventions for Observed Data with IRD/REACH

Each exposure taken with IRD and REACH produces a pair of FITS files: one for the Y/J-band detector and the other for the H-band detector.

The prefix of each file name varies depending on the observation mode:

• IRDA: Data obtained via Gen2, the observation control system of the Subaru Telescope.

  • The even-numbered FITS file (e.g., IRDA00041510.fits) contains the Y/J-band data.

  • The odd-numbered FITS file (e.g., IRDA00041511.fits) contains the H-band data.

• IRDBD or IRDAD: Data obtained directly from the detector PC, mainly used for calibration purposes.

  • IRDBDxxxxxxxx.fits: Y/J-band data

  • IRDADxxxxxxxx.fits: H-band data

Names of Calibration Dataset

• thar (Th-Ar): Thrium-Argon hollow cathode lamp for wavelength reference

• FLAT_COMB, FLAT_STAR: ‘FLAT’ means the light from a white lamp for flat fielding. ‘_COMB’ and ‘_STAR’ denote the injection to the comb-fiber (mmf1) and star-fiber (mmf2), respectively.

  • In the FLAT_COMB image, flat light injected on the comb fiber is also leaking into the star fiber, and two flat lights, one strong and one weak, are seen at each order.

  • In the pipeline, by utilizing this feature, all the apertures are identified in the FLAT-COMB, and then selected the ones to be used.

  • The advantage of this method is that there is no need to change frame IDs when switching fiber to analyze.

• ThAr-ThAr: Calibration image with ThAr light inject to both fibers.

• COMB-COMB: Calibration image with LFC light inject to both fibers.