A guided tour to VLTI

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Data and calibration of
A M BE R / V L T I Florentin Millour
( )
And the A.M.BE.R. consortium
Osservatorio Astrofisico di Arcetri
Consortium website : http://amber.obs.ujf­grenoble.fr
Accardo Matteo, Acke Bram, Agabi Karim, Altariba Evelyne, Antonelli Pierre,
Arezki Brahim, Aristidi Eric, Baffa Carlo, Beckmann Udo, Behrend Jan,
Blöcker Thomas, Bonhomme Serge, Bresson Yves, Busoni Simone, Casoli Fabienne,
Cassaing Frédéric, Chelli Alain, Clausse Jean­Michel, Colin Jacques, Connot Claus,
Debouzy Geneviève, Delboulbé Alain, Domiciano de Souza Armando, Dugué Michel,
Duvert Gilles, Driebe Thomas, Exertier Pierre, Feautrier Philippe, Ferruzzi Debora,
Forveille Thierry, Fossat Eric, Foy Renaud, Fraix­Burnet Didier, Gallardo Agustin,
Gennari Sandro, Giani Elisabetta, Gil Carla, Glentzlin André, Glück Laurence,
Heiden Manfred, Heininger Matthias, Hernandez Oscar, Hofmann Karl­Heinz,
Kamm Daniel, Kern Pierre, Lagarde Stéphane, Lagrange Anne­Marie, Le Coarer Étienne,
Le Contel Danielle, Lecontel Jean­Michel, Lisi Franco, Lopez Bruno, Malbet Fabien,
Magnard Yves, Marconi Alessandro, Mars Gilbert, Martinot­Lagarde Grégoire,
Mathias Philippe, Mège Pierre, Millour Florentin, Monin Jean­Louis, Montmerle Thierry,
Mouillet David, Mourard Denis, Nussbaum Edmund, Ohnaka Keiichi, Pacheco José,
Pacini Franco, Perraut Karine, Perrier Christian, Petrov Romain, Puget Pascal,
Rabbia Yves, Rebattu Sylvestre, Reynaud François, Richichi Andrea, Robbe Sylvie,
Roussel Alain, Sacchettini Michel, Salinari Piero, Salvati Marco, Schertl Dieter,
Solscheid Walter, Stee Philippe, Stefanini Paolo, Tallon­Bosc Isabelle, Tallon Michel,
Tasso Daniel, Tatulli Éric, Testi Leonardo, Vakili Farrokh, Valtier Jean­Claude,
van der Lühe Oskar, Vannier Martin, Ventura Noël, Weigelt Gerd, Zins Gérard
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Cophased and collimated beams from telescopes
Detector
Telescopes
“Basic” interferometer
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Detector
Telescopes
3T monomode spectro­interferometer
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
AMBER
Spectrograph
and detector
VLTI
Calibration and
alignment units
Osservatorio Astrofisico di Arcetri
Spatial filters
(optical fibers)
F. Millour, ESO, 26/01/07
The AMBER raw data
Photometric beams
Interferometric beam
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Spectral calibration
² Vel
A­type star
Telluric lines
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Spectral calibration
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Spectral calibration
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Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Flux (e­)
Flux (e­)
The P2VM algorithm
#Pixel
#Pixel
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Flux (e­)
Flux (e­)
The P2VM algorithm
#Pixel
#Pixel
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
X =
P2VM
"Instrumental fringes"
"cleaned" data
Matrix multiplication
Osservatorio Astrofisico di Arcetri
Observables
(Complex coherent flux)
F. Millour, ESO, 26/01/07
AMBER observables
Complex coherent flux :
i, j
C =2 N V T 
measured on M frames
Photometric beams
Interferometric beam
Spectrum :
S = N()
Visibility : Vi,j = |Ci,j()| / N()
Phase closure :
123 = atan<C1,2C2,3C*1,3>
Diff. phase :
i,jdiff
Diff. visibility :
Vi,jdiff
“Phase closure” of diff. phases :
123diff 1,2diff2,3diff3,1diff
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The amdlib library

Handles all the data reduction steps, both online and offline

GUI : Gasgano, ammYorick, GreG
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
G. Li Causi 2006
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
The P2VM algorithm
Is valid IF :

the instrument is stable enough between calibration and observations

SNR on the P2VM is enough

The spectral channels are thin enough

The detector cosmetics is well enough known

The wavelength calibration is OK
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Instrumental contrast on the sky
Lab visibility :
 On sky exp. visibility (FSU) :
 On sky exp. visibility (no FSU) :
0.85
0.85
0.60
NO FINITO ! :
 Average on­sky UT visibility :
 Average on­sky AT visibility :
0.20
0.60

“VLTI / UT vibrations"
OPD modulation between 0.2 & 1m
Frequency >20Hz
We have a problem
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Instrumental contrast on the sky
Lab visibility :
 On sky exp. visibility (FSU) :
 On sky exp. visibility (no FSU) :
0.85
0.85
0.60
NO FINITO ! :
 Average on­sky UT visibility :
 Average on­sky AT visibility :
0.20
0.60

“VLTI / UT vibrations"
OPD modulation between 0.2 & 1m
Frequency >20Hz
We have a problem
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
30 micron RMS
OPD measurements
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Puissance (m2)
Conan & co.
1995
Puissance (normalisée)
Vibrations and OPD
Fréquence (Hz)
Kervella
2005
Fréquence (Hz)
­2/3
­8/3
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Puissance (m2)
Conan & co.
1995
Puissance (normalisée)
Vibrations and flux
Fréquence (Hz)
Kervella
2005
Fréquence (Hz)
­2/3
­11/3
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Puissance (m2)
Conan & co.
1995
Puissance (normalisée)
Vibrations and flux
Kervella
2005
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Fréquence (Hz)
Fréquence (Hz)
­2/3
­11/3
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
0,40
0,05
“transfert function”
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
0,40
0,05
“transfert function”
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
0,40
0,05
“transfert function”
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
0,40
0,05
“transfert function”
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
0,40
0,05
“transfert function”
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
“transfert function”
0,40
0,05
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Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Differential phase bias
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
“Today's” performances

Medium spectral resolution (R=1500)

Bright star (K=3.5)
Typical uncertainties
Today
Visibility
0.05
Differential visibility
0.01
Phase closure (rad)
0.05
Differential phase (rad)
0.01
Osservatorio Astrofisico di Arcetri
Specs
0.01
0.01
0.02
0.01
F. Millour, ESO, 26/01/07
“Today's” performances


Low resolution (R=35)
See poster Cruzalèbes et al
Bright star (K=5)
Typical uncertainties
Today
Visibility
?
Differential visibility
?
Phase closure (rad)
0.01
Differential phase (rad) 0.001*
Specs
0.01
0.01
0.002
0.001
* chromatic dispersion : amplitude ~ from 0.1 rad to 1 rad
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
What could be improved


AMBER side :
−
Jitter estimation/correction
−
Detector fringe pattern
−
LR data
−
Closure phase and differential phase high accuracy
VLTI side
−
VIBRATIONS !
−
FINITO
−
Time delay between measurements
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Osservatorio Astrofisico di Arcetri
F. Millour, ESO, 26/01/07
Thank you for your attention
Any question ?
F. Millour, ESO, 26/01/07