EMIR Near Infrared Multi-Object Spectrograph for GTC

EMIR Espectrógrafo Infrarrojo Multi-Objeto para GTC

EMIR in a nutshell

EMIR offers  three  main observing  modes:  Imaging, Long slit and Multi-slit spectroscopy. The  spectral  format  is  fixed  for  both  spectroscopic  observing  modes using the CSU bars configuration.

 

Spectral Range	0.9 - 2.5 µm [1.1 - 2.5 µm]	MOS mode
Top priority	MOS in K band	FOV	6.7 x 4 arcmin (55 slitlets)
Spectral Resol.	5000, 4250, 4000 (JHK)	Sensitivity	K ~ 20.1 in 2h @ S/N = 5 (continuum)
Spectral coverage	1 single window/exp.		1.4 x 10-18 erg/s/cm2/Å @ S/N=6 (line)
Detector	HAWAI2 20482	Image Mode
Plate Scale	0.2 arcsec/px	FOV	6.7 x 6.7 arcmin
Image quality	Θ80 < 0.3 arcsec	Sensivity	K ~ 22.8 in 1h @ S/N = 5 in 0.6 arcsec aperture

 

Characteristics	Value
Pixel format	2048x2048
Pixel size	18 µm/pixel
Filling factor	90
Spectral Response	0.9 - 2.5 microns
Dark Current (77 K)	< 0.1 e-/s
Read noise (77 K)	< 5 e-
Gain
Well depth
Quantum efficiency (77K, 2.3 µm)	75%

 

EMIR band filters cover a spectral range of 1.6 microns, from 0.9 to 2.5, with three set of filters, broad and narrow band, plus some order sorting elements. The following table provides the measured parameters at the IAC optical laboratory at room temperature at the centre of the filter and with normal incidence (Broad Band: Bb; Narrow Band: Nb and Order Sorting: Os). The transmission was measure using a collimated beam and a temperature 20 ° C. Allow for a shift of 0.7nm towards the blue to convert to cryogenic temperature.

 

© 2025 EMIR Near Infrared Multi-Object Spectrograph for GTC -  Instituto de Astrofísica de Canarias