Deblending issues working report MontePorzio 16-04-08 CU5#DU11 Luigi Pulone@ INAF-OA Roma INAF -...
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Transcript of Deblending issues working report MontePorzio 16-04-08 CU5#DU11 Luigi Pulone@ INAF-OA Roma INAF -...
Deblending issues working report
MontePorzio 16-04-08 CU5#DU11 Luigi Pulone@ INAF-OA Roma
• INAF - Teramo Observatory: Anna Piersimoni, Giorgia Busso
• INAF - Rome Observatory (Monte Porzio Catone): Giacinto Iannicola, Luigi Pulone, Marco Castellani
• ASI – ASDC (Frascati) : Licia Troisi, Roberto Buonanno, Giuliano Giuffrida
Main Task Obtain a clean spectrum for every observed
source, resolved in the astrometric field
DU11 in CU5: Leiden (NL), Cambridge (UK), Roma,Teramo (IT)
Data Processing and Analysis Consortium
ESA Gaia project team ESA Ground segment oversight
GAIA Science Team DPAC
CU3Core processing
CU1System architecture
CU6Spectroscopic processing
CU5Photometric processing
CU2Simulazioni
CU4Object analysis
CU7Variability analysis
CU8Astrophysical parameters
Coordination Unit 5
Riduzione fotometrica e calibrazione sia in banda G che negli spettri
• Estrazione dei parametri delle identificazioni per ogni passaggio nel campo astrometrico
• Elaborazione ed accumulazione dei dati in banda G, RP, BP
• Identificazione stelle standard, variabili, analisi
oggetti multipli
• Calibrazione interna ed esterna dati fotometrici
• Photometric science alerts
Gli obbiettivi di GAIA
Accuratezza-4 μarcsec a V=10 10 μarcsec a V=15 0.2 marcsec a V=20
-Velocità radiali con accuratezza di qualche km/s complete fino a V=17.5
- Survey celeste con risoluzione spaziale di 0.1 arcsec fino a V=20
- spettrofotometria multi-epoca fino a V=20
- definizione di un sistema inerziale legato ai quasar più lontaniRisultati
- GAIA posizionerà 300 milioni di stelle nello spazio delle fasi a 6 dimensioni e 1 miliardo di stelle nello spazio delle fasi a 5 dimensioni
Formazione stellare nella Via Lattea
Astrofisica stellare
Struttura Galattica
Fisica fondamentale
Sistema di riferimentoSistema
solarePianeti extrasolari
Binarie e nane brune
Confronto fra Hipparcos e GAIA
Oggetti
galassie
quasarSupernovae extrag.
Nuovi asteroidibinarie
Nane bianche
Nane brune
Sistemi planetari
Catalogue
Schedule
2000 2004 2008 2012 2016 2020
Acceptance
Technology Development
Design, Build, Test
Launch
Observations
Analysis
Early Data
Concept & Technology Study ESA SCI 2000(4)
Re-Assessment: Ariane Soyuz
To L2
Assumed start of Phase B2
Satellite and System
• Mass: 1700 kg (payload 800 kg)• Power: 2000 W (payload 1200 W)
• ESA only mission• Launch date: 2011 • Lifetime: 5 years• Launcher: FREGAT• Orbit: L2• Ground station: Perth or Madrid• Data rate: 1 Mbps
Il percorso ottico
spettrofotometro B
spettrofotometro R
GAIA – Simulazione campo stellare media densità
15 BP/ RP Flux extraction
Time intervalidentif iers
Scan coverage
I oADPCdata-base
Raw BP/ RPimages
Raw BP/ RPimages
Apply basiccalibrations 15.2
Calibrated BP/ RPimages
Evaluate sourcecrowding attransit level
15.3
I dentif y observationswithin scan coverage
15.1
I solatedimages
Crowdedimages
Basic f luxextraction
15.4Crowded f ield
f lux extraction 15.5Extracted and cleaned
BP/ RP spectra
I oADPCdata-base
I oADPCdata archive
I oADPCdata archive
Nominalattitude
evaluation
4.2
AB Apr. 2007
I oADPCdata-base
Calibrationf iles
ESAC data base
Auxilliary dataG, source positions,
window conf igurations,etc
OA Teramo
OA Roma, ASI-ASDC
Teramo group• Background modelling
• Studying relationships between AL and AC size of the source and APs
• Source crowding evaluation at source and transit level
• Create connected groups on the basis of the contamination degree
• Individuate isolated objects
BP photometer:AC width vs. G mag
AC
AL
BP photometer:AL length vs. G mag
High density regions, like Galactic bulge low-extinction regions and central regions of the Large Magellanic Cloud, present a challenge both for board data-handling and for the ground-based reduction while being crucial for the Gaia science case.
A recent result: expected frequency of the deblending procedure for the whole mission lifetime (~10%) taking into account the overlapping of the two field of view.
Figures from Marrese & Busso 2007
● Deblending of connected groups
due to:
• overlapping of spectra of different sources in connected windows
• objects in nearby windows whose spectra extend into the program window
• objects for which the on-board detection software has not assigned a window • barely detectable sources beyond the survey magnitude limit (20 < G < 22).
Rome group
The numerical approach
The analytical approach, has shown some limitations in reproducing high metallicity and low temperature spectra.
The Rome group is now developing and testing a new deblending technique based a Marquardt-like method for non linear least square minimization.
This approach is much more straightforward and makes use of the entire morphology of the spectrum simultaneously in both the Blue and Red bands.
First results appear encouraging.
new approach
template library 3500 < Teff <
20000°K, -5.00 < [M/H] <
1.00 comparison between templates and input spectrummodels interpolation
OLD ANALYTICAL vs NEW NUMERICAL APPROACH
OLD
NEW
M/H = -5
T=8000 K
Logg=4.5
Av=0.
testT = 9250°K, [M/H]= -4.5, -0.2, 1.0
9250°K
[M/H] Teff Teff/Teff
Simulated B Flux
Fitted B flux
fB/fbSimulat
ed R Flux
Fitted R Flux
fR/fR
-4.5 9112 0.015 49564 49263 0.0061 28014 27873 0.0050
-0.2 9254 0.0004 49006 49274 0.0055 27626 27349 0.0100
1.0 9244 0.0006 49345 49064 0.0057 27202 27250 0.002
Two blended spectra in the same window
Teff=20000°K, [M/H]=-4.5 + Teff=9000°K, [M/H]=0.00Shift: 10 pixel
Recovering of blended spectra
Teff Teffest Teff/Teff
Simulated B Flux
Fitted B flux
fB/fbSimulat
ed R Flux
Fitted R Flux
fR/fR
9000°K 9393 0.0437 48346 48740 0.0081 27113 27115 0.0000
20000°K 20000 0.0000 54101 50466 0.0672 20822 19526 0.0622
Teff=20000°K, [M/H]=-4.5 + Teff=9000°K, [M/H]=0.00Shift 10 pixel
Central star: V=13 T=6000 [M/H]=0Blended 1: V=14 T=10000 [M/H]=0.5 dX=15 px dY=2 pxBlended 2: V=15 T=8000 [M/H]=-0.5 dX=13 dY=3
Next steps:
• Include log g into the reference theoretical template
• Take into account the Av
• Consider the paving strategy, cut windows etc. to rebuild connected and contaminated spectra