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LISA spectrographLong slit Intermediate resolution Spectrograph for Astronomy
Performances and application
Christian Buil
Active Spectroscopy in AstronomyEssen – 7 May 2011
1Essen - 7 May 2011
Spectrograph resolution categories ( R)
High resolution Lhires R = 16000
eShel R = 11000
Medium resolution(or intermediate)
LISA R = 500 to 1000
Low resolutionStar Analyser R = 100 to 200
2Essen - 7 May 2011
Spectral resolution (R) and luminosity (L) : a complementary effortR x L = constant
Planetary nebulae NGC 2392 – 15 x 30 seconds
Faint object spectroscopyThe example of Star Analyser : very low resolution, very high luminosity
3Essen - 7 May 2011
But do not mystake luminosity and detectivity !
Faint object spectroscopy
One limitation of slitless spectroscopy : sky background pollution
The symbiotic star V1016 Cyg
Another limitation of SA : optical aberration
Chromatic coma : a source of detectivity degradation (bad capacity to concentrate energy)
Grism improvement
4Essen - 7 May 2011
Faint object spectroscopy
The importance of an entrance slit
Large slit
Narrow slit
The sky background level if proportionnal to the slit wideThe backgroung photon noise is proportionnal to the square root of slit wide
5Essen - 7 May 2011
The LISA concept (1/2)
- Ajustable entrance slit by step (from 15 microns to 100 microns) (capacity to optimise spectral resolution to a specific target)
- Fast input beam : up to f/5 input i.e. high luminosity spectrograph (reduce potential guidance problem because shorter focal length, capture of faint surface objet like galaxies, comets, …
- Optimized spectral dispersion to modern camera (2 A / pixel sampling on a popular KAF8300 CCD ship)
- Balance between power resolution capacity and scientific interest (R = 500 to 1000 typically) – Sodium doublet is just separated with a 23 microns slit
Mg I,2,3 NaDA, D2 Halpha
2D spectrum of moon surface
6Essen - 7 May 2011
- Wide spectral range in one shot : 3950 A – 7200 A (+ IR option)
- Integrated calibration system (neon lamp + tungsten lamp) : easy to use and standard pipeline processing. Possibility to fully automatize acquisition.
- Compact and moderate weigth : adaptable on small refractor and refractor.
- Low cost : large diffusion if possible!
The LISA concept (2/2)
7Essen - 7 May 2011
Optical design
Internal grandissement G = 0,603
For example: if the telescope focal / diameter ratio is 6, the final F/D is 6 x 0,603 = 3,6(LISA is equivalent to a focal reducer).
Essen - 7 May 2011 8
Mechanical design
9Essen - 7 May 2011
Mechanical design
Calibration unit Ajustable grating angle
10Essen - 7 May 2011
Pointing and guidance system
High reflectivity slitVery constant edge
High quality slit image on the guidance camera(here M104 galaxy with a Watec 120N)
11Essen - 7 May 2011
LISA on a Celestron 11 telescope
12Essen - 7 May 2011
Calibration module (spectral calibration and flat-field)
Electromagnetic system – 12 V power – Remote operation possible
Essen - 7 May 2011 13
Interfaces
Optimal input focal ratio f/5 to f/7A fast Newton telescope is ideal (achromatism)
For SC Telescope : focal reducer(here a Baader Alan Gee - final ratio f/6.8)
Fast adaptation for CCD camera and DSRL
14Essen - 7 May 2011
Essen - 7 May 2011 15
Example of setup with Atik CCD cameras
Atik 314L for spectra acquistion (1390 x 1040 x 6.45 µm pixel size)Readout noise : 4.5 e-, Camera gain : 0.250 e-/ADU, typical quantum efficiency @ 656 nm : 55%
Atik Titan for pointing and guiding functions(faint object identification capability + rudimentary photometry measure on the targets)
Low cost solution for LISA, low mass on the telescope, high performances
Amovible entrance slitHigh precision chromium serigraphy
Slit 23 microns – R = 1100W = 2,5 arcsec on C11 f/6.8
Slit 50 microns – R = 600W = 5.4 arcsec on C11 f/6.8
15 – 19 – 23 – 32 microns (option 50 – 75 – 100 microns + 19 microns hole)
16Essen - 7 May 2011
Automatised processingRlhires application
17Essen - 7 May 2011
Automatic spectral calibration by using observed type A, B or G star spectra and internal neon lamp spectrum
Fit dispersion law with a 3e order polynomial function (typical RMS error : 0.3 to 0.4 A) 18Essen - 7 May 2011
Many tools available : computation of heliocentric velocity, H2O removal, atmopsheric transmission, spectra database, …. French/english interface
19Essen - 7 May 2011
Slit 23 µmR = 1100
Slit 50 µmR = 600
Slit 100 µmR = 290
D = 12.8 cmF/D = 8
12.5 13.1 13.4
D = 28 cmF/D = 6.8
13.6 14.6 15.0
D = 35 cmF/D = 6.8
13.9 14.9 15.4
D = 50 cmF/D = 6.0
14.4 15.5 16.2
D = 100 cmF/D = 6.0
15.2 16.3 17.2
Slit 23 µmR = 1100
Slit 50 µmR = 600
Slit 100 µmR = 290
D = 12.8 cmF/D = 8
13.1 13.6 13.9
D = 28 cmF/D = 6.8
14.5 15.2 15.6
D = 35 cmF/D = 6.8
14.8 15.6 16.1
D = 50 cmF/D = 6.0
15.3 16.3 16.9
D = 100 cmF/D = 6.0
16.1 17.3 18.2
Integration time : 1 hour (6 x 600 sec)Signal to noise ratio = 10 (@ Halpha)
Type A0V star – Seeing = 3 arcsecCCD KAF-8300 (Binning 1 x1)
Limit magnitude
Altitude 0 m - Suburban Altitude 3000 m – Dark sky
20Essen - 7 May 2011
Slit 50 µmR = 600
Slit 100 µmR = 280
D = 12.8 cmF/D = 8
13.7 14.0
D = 28 cmF/D = 6.8
15.4 15.8
D = 35 cmF/D = 6.8
15.8 16.2
D = 50 cmF/D = 6.0
16.4 17.0
D = 100 cmF/D = 6.0
17.4 18.3
Slit 50 µmR = 600
Slit 100 µmR = 280
D = 12.8 cmF/D = 8
14.2 14.5
D = 28 cmF/D = 6.8
15.8 16.2
D = 35 cmF/D = 6.8
16.2 16.7
D = 50 cmF/D = 6.0
16.9 17.5
D = 100 cmF/D = 6.0
17.8 18.7
Integration time : 1 hour (6 x 600 sec)Signal to noise ratio = 10 (@ Halpha)
Type A0V star – Seeing = 3 arcsecAltitude 3000 m – Dark sky
Limit magnitude (function of detector type)
CCD KAF-8300 (Binning 2 x2) CCD KAF-3200 (Binning 2 x2)
3 hours integration (18 x 600 sec) – Slit 50 µm – D = 28 cm F/D = 6.8 M = 16.1 (KAF-8300)M = 16.5 (KAF-3200)M = 16.6 (ICX424AL)
21Essen - 7 May 2011
Slit 50 µmR = 600
Slit 100 µmR = 280
D = 12.8 cmF/D = 8
14.3 14.7
D = 28 cmF/D = 6.8
16.0 16.3
D = 35 cmF/D = 6.8
16.4 16.8
D = 50 cmF/D = 6.0
17.1 17.6
D = 100 cmF/D = 6.0
18.1 19.0
CCD ICX285AL (Binning 2 x2)
Observation with LISA spectrograph
22Essen - 7 May 2011
Star Analyser
Typical aspect of LISA 2D spectraSymbiotic star V1016 Cyg
2D spectrum before sky removal (23 µm slit)
2D spectrum after sky substraction
23Essen - 7 May 2011
Symbiotic star V1016 Cyg (V = 11.2) : lines identification
24Essen - 7 May 2011
First step : observation of normal stars (1/2)
25Essen - 7 May 2011
First step : observation of normal stars (2/2)
26Essen - 7 May 2011
Survey of know Be Star + and detection of new Be star
Beta Lyrae (Shelyak) – 15 x 30 s
Rapid scan of B and A star for Halpha emission signature (5-10 minutes exposure)(list of nearly 1000 stars – magnitude < 10)
27Essen - 7 May 2011
Faint Be stars observation (BeSS)
V = 6.09 – 9 x 120 s V = 4.74 – 8 x 60 s
V = 8.62 – 6 x 300 s (new BeSS entry) V = 8.63 – 7 x 300 s (new BeSS entry) 28Essen - 7 May 2011
Survey of cataclysmic(novae like)
SS Cyg outburst (V = 8.7) – April 4.1, 2011
29Essen - 7 May 2011
List of cataclysmic star (François Teyssier)
…
30Essen - 7 May 2011
Outburst of cataclysmic V694 MonHigh velocity wind – Fast evolution
31Essen - 7 May 2011
V694 Mon – Visible + IR capacity of LISA spectrograph
32Essen - 7 May 2011
Recurent nova T Pyxidis : day to day monitoring of profile evolution
33Essen - 7 May 2011
T Pyxidis 2D spectrum
6 arcsec refractionat 12 degree elevation
Paralactic angle
Observation at very low angular elevation : associated problemT Pyxidis declinaison = -32 degrees
Horizon
34Essen - 7 May 2011
Nova Sagittarii 2011 #2 (V5588 Sgr)V = 13.2
35Essen - 7 May 2011
Eruption of Herbig Ae/Be star Z CMa
Vis + IR spectrum
Detail of IR spectrum
36Essen - 7 May 2011
MIRA starR Leo at V = 8.5
Wide band spectrum
37Essen - 7 May 2011
HD 56925 in NGC 2359 nebula
Wolf-Rayet star HD 56925WR 7 – V = 11.7
38Essen - 7 May 2011
R Mon in NGC 2261 nebula3 x 600 s @ R = 1000
Messier 1 (Crab nebulae) - 5 x 600 s @ R = 600
39Essen - 7 May 2011
SUPERNOVASN 2011ae in MCG-3-30-19
40Essen - 7 May 2011
SUPERNOVASN 2011by in NGC 3979
41Essen - 7 May 2011
Essen - 7 May 2011 42
Messier 104Sombrero galaxy
Audela autoguiding
2D spectrum
Na rest = 5892.9 A - Na observed = 5916.9 A – z = (5916.9 – 5892.9) / 5892.9 = 0.0041 (17 Mpc)
NGC 4151
NGC 4051
Active galaxies (Seyfert)
43Essen - 7 May 2011
McDonald 2,1 mK. Thompson AJ, 395, 404,417, 1992
Quasar 3C273
Observed Halpha at 7584 Az = (7584 - 6563)/6563 = 0.155(official z = 0.158)
44Essen - 7 May 2011
LISA infrared version
Quasar Mrk 205 observation(V = 15.5)
45Essen - 7 May 2011
Observed z = 0.0710 (official value z = 0.0705)
Quasar Mrk 2057 x 600 sec. – 50 µm slit
46Essen - 7 May 2011
Thank you
47Essen - 7 May 2011