LIRIS
Long-slit Intermediate Resolution Infrared
Spectrograph for the WHT
A. Manchado + LIRIS Team (IAC)
LIRIS
Focal Station
Spectral Range
Array Format
Scale at detector
Observing modes
FOV
Sensitivity
JENAM Granada 2004
Instrument features
Cassegrain
0.9 - 2.4 µ m
Rockwell Hawaii 1024x1024 HgCdTe
0.25 arcsec / pixel
Imaging ,Long-slit Spectroscopy, Multi-object spectroscopy,
coronography with apodization masking and Polarimetry
Imaging
4.2 x 4.2 arcmin
K=20.9 H=22.4, J=23.5, Z=23.9 for t=1hr, S/N=3, in 0.5 arcsec
seeing.
LIRIS
Spectroscopy mode
Available Slits
(0.5", 0.75", 1", 2.5", 5") x 4.2 armin
Spectral coverage
From 0.887 to 1.531 µ m [bands Z and J, R=1000]
From 1.388 to 2.419 µ m [bands H and K, R=1000]
From 1.125 to 1.350 µ m [bands J , R=2500 ]
From 1.467 to 1.793 µm [bands H , R=2500]
From 1.980 to 2.420 µ m [bands K , R=2500]
Sensitivity
R=1000: K= 18.1, H=19.4, J=20.8, Z=21.5 (continuum)
R=3000: K=17.5, H=19.0, J=19.8, Z=20.7 (continuum)
In both cases for t=1hr, S/N=3, FWHM=0. 5" .
Multi-object Spectroscopy mode
Number of masks
JENAM Granada 2004
8 multislit masks available (up to 24 slits per mask).
Comparison with other NIR spectrographs
LIRIS
Telescope
Instrument
Wide field
Spectral
Aperture Scale
FOV Resolution
(m)
(“/pix) (arcmin)
ISSAC
8
NIRSPEC
10
OmegaCass
SOFI
0.15 2.5 x 2.5 500, 3000
0.14
0.4
5x5
Coronography
MOS
Polarimetry
no
yes
2500, 10000
no
420,1050
no
3.5
0.3
3.6
0.27 4.7 x 4.7 1000, 2200
no
no
image
image
no
no
no
no
image,
LIRIS
4.2
0.25 4.2 x 4.2 1000, 2500
NICS
3.5
0.25 4.3 x 4.3 400, 1200,
3.5
0.3
IRIS2
JENAM Granada 2004
10x10
yes
spectroscopy
(8 masks)
no
image,
spectroscopy
yes
1000, 2400
(3 masks)
no
yes
no
no
LIRIS
12:05:55
AMH
Optical Concept
100.00
LIRIS IMAGER/SPECTROMETER
JENAM Granada 2004
MM
IAC 22-Feb-99
LIRIS
50%eed
JENAM Granada 2004
13 6 13
6 8 6
13 6 13
80%eed
17 12 17
12 12 12
17 12 17
100%eed
24 18 24
18 18 18
24 18 24
Slit wheel
LIRIS
Dimensional verification
Functional verification in the test cryostat
Pre-integration in the LIRIS cryostat
JENAM Granada 2004
Multi-slit (Electro discharging
machining)
LIRIS
Multi-slit mask 75 x 75 mm
Slit (1mm x130µm)
JENAM Granada 2004
Slit magnification
LIRIS
Central and camera wheels
Pre-integration in the LIRIS cryostat
Central wheels
module
Camera wheel
JENAM Granada 2004
LIRIS optical bench
LIRIS
JENAM Granada 2004
LIRIS
Detector vs Temperature
QE increases with T
(65K→80K):
15% in Ks band
30% in J band
Dark current and read out
noise constant
T higher than 70K, hot
pixels increase
JENAM Granada 2004
LIRIS
JENAM Granada 2004
Efficiency in image mode
LIRIS
Zero points and sky brightness
J
H
Ks
Instrumento
ZP
Msky
ZP
Msky
ZP
Msky
LIRIS
25.0(24.8)
15.2/16.6
25.3 (25.2)
13.4/14.8
24.6(24.6)
12.6/13.1
INGRID
24.9
15.4/16.4
24.9
13.5/14.7
24.4
11.9/12.5
NICS
24.4
15.0/16.0
24.6
13.4/14.7
24.1
12.5/13.0*
(K)
NOTCAM
Higher
Higher QE
QE
JENAM Granada 2004
23.8
15.5
TTdet
60K→ 70K
det 60K→ 70K
23.9
14.0
23.3
12.8
LIRIS
Pupil image
J band with sky
background
Ks band:
Edge 1%
Central part 32% (0.2mag)
Lyot mask with central oscuration
JENAM Granada 2004
LIRIS
JENAM Granada 2004
Sky emission
LIRIS
l
Saturation:
F
F
l
Image: J ⇒ tsat > 340s; H ⇒ tsat > 80s; Ks ⇒ tsat > 48s
Spectroscopy: ZJ ⇒ tsat > 6300s; HK ⇒ tsat > 1000s
Background noise limited (photon noise > 3*ReadOut):
F
F
F
Image: J ⇒texp > 4s; H ⇒ texp > 2s; Ks ⇒ texp > 1.5s
Spectroscopy: ZJ ⇒ texp > 1036s; HK ⇒ texp > 346s (mndr=1)
ZJ ⇒ texp > 500s; HK ⇒ texp > 170s (mndr=4)
JENAM Granada 2004
LIRIS
JENAM Granada 2004
Efficiency in spectroscopy mode
(atmosphere+WHT+LIRIS)
Internal flexures
LIRIS
ZD=45
JENAM Granada 2004
LIRIS
Calibration
Calibration
fields⇒
fields⇒ all
all targets
targets
on
on slit
slit
JENAM Granada 2004
MOS
CIV Detection in z=6.4 QSO
LIRIS
JENAM Granada 2004
LIRIS
Milestones
Kick off, February 1998
PDR, March
1999
CDR, March
2000
Fabrication starts, September 2000
Subsystem AIV starts, January 2001
Instrument AIV starts, December 2001
First commissioning with engineering array, February 2003
Second commissioning with science array, March 2004
Visiting astronomer instrument (CAT/PATT), August 2004
Commissioning polarimetry mode, October 2004
Grisms R~2500, February 2005
JENAM Granada 2004