FRENEL Meeting, Nice, 23-25 September 2009
FRESNEL Imager: FRESNEL Imager: Extragalactic Science in Extragalactic Science in the UV-Optical domainsthe UV-Optical domains
Roser Pelló Roser Pelló Laboratoire d’Astrophysique de Toulouse-TarbesLaboratoire d’Astrophysique de Toulouse-Tarbes
FI and extragalactic studiesFI and extragalactic studies Spatial resolution
Wavelength coverage (100nm to 10 microns)
High dynamic range
FI ...FI ...
starts operations after JWST, ALMA and possibly SKA, ...
it is intended to be a follow up rather than a survey facility
could be efficiently used to target galaxies selected from utra-deep photometric and spectroscopic surveys
Mapping the Star Formation of galaxies, from the local universe to ~75% look back time (UV, z~0 to 2)
Constraining the physical properties of the first galaxies (IR)
Extragalactic studies in the UVExtragalactic studies in the UV
Galaxy Evolution Explorer (GALEX, 2003-)
GALEX FUV
GALEX NUV
Ex.: composite Ex.: composite spectra of high-z spectra of high-z galaxies observed galaxies observed in the optical in the optical domaindomain(VVDS Survey(VVDS SurveyLe Fevre et al. 06,Le Fevre et al. 06, Paltani et al. 07)Paltani et al. 07)
Composite spectra of z~3 LBGs, for different Ly a equivalent widths, observed in the optical (lambda~4500-7000 A)
(Shapley et al. 2003)
Line diagnostics and redshiftLine diagnostics and redshift
near-IR
visible
Ly a
HeII 1640
[OII]3727Hb + [OIII]5007Hb + [OIII]5007Ha + [NII]
Line diagnostics and redshiftLine diagnostics and redshift
Line diagnostics shift towards the near-IR (lambda>1 micron)
Ha/[NII][S II]
AGN
Starbursts
Empirical Empirical discrimination discrimination between between AGN/starburstsAGN/starbursts
From Erb et al. 06
87 combined spectra of galaxies at z~2 (~14-15 specta/ mass bin)
Star-formation rate determinationsStar-formation rate determinations
Different calibrations available :
UV continuum flux
FIR emission H alpha [OII]3727 (Ly alpha)
Based on the properties of the integrated population
Groves 2005Groves 2005
(Kennicutt 1998, Schaerer 1999, ...)
Star-formation rate determinationsStar-formation rate determinations(from Schaerer 1999)
IMFIMF
UV continuum flux density
L(Ha) luminosity
Cosmic SFR densityCosmic SFR density Inhomogneous SFR Inhomogneous SFR
indicators at different indicators at different redshiftsredshifts
Old paper by Steidel et al. 1999... Old paper by Steidel et al. 1999...
Lilly et al. 96Lilly et al. 96
Connolly et al. 97Connolly et al. 97
Madau et al. 96Madau et al. 96
Steidel et al. 99Steidel et al. 99
• H alpha z< 0.5H alpha z< 0.5• [OII]3727 0.5<z<1.5[OII]3727 0.5<z<1.5• continuum UV z > 1.5continuum UV z > 1.5
Cosmic SFR densityCosmic SFR density
Inhomogneous SFR Inhomogneous SFR indicators at different indicators at different redshiftsredshifts
Lilly et al. 96Lilly et al. 96
Connolly et al. 97Connolly et al. 97
Madau et al. 96Madau et al. 96
Steidel et al. 99Steidel et al. 99
• H alpha z< 0.5H alpha z< 0.5• [OII]3727 0.5<z<1.5[OII]3727 0.5<z<1.5• continuum UV z > 1.5continuum UV z > 1.5
Bouwens et al. 2008Bouwens et al. 2008
GALEXGALEX
HDF
Dust extinction correction is an Dust extinction correction is an issue... issue...
D'apres Schiminovich et al. 05
Extragalactic studies in the UV with FIExtragalactic studies in the UV with FI
UV (restframe) observations ==> Star Formation activity
UV-calibrated Star Formation Rate measurements Lyman alpha properties
Metal abundances Extinction UV (SF) – morphology Recent (age<~ 100 Myr) SF history
A complete view of star-formation at 0<z<2 (75% of light travel time... )
Calib
ration in
the local u
niverse
Ly alpha emissionLy alpha emission
IZw18
A complex Ly a emission in aLocal sturburst (Atek et al. 09)
4''
HST/STIS
Ly alpha emissionLy alpha emission
A complex Ly a emission in aLocal sturburst (Atek et al. 09)
- Empirical estimate of Ly a escape fraction in a statistically significant sample of z~0-0.3 Lya emitters detected by GALEX (24 galaxies)
Atek et al. 2009
The size of local starburst galaxiesThe size of local starburst galaxies
From Ostlin et al. 08
5''x5''
7.5''x7.5''
15''x15''15''x15''
15''x15''
15''x15''
•- Emission-line images of local starbursts (Ha, [OIII] and Hb).
•- Comparison between Lya, Ha and UV continuum emission
Ly a emission
Ly alpha/UV emission in distant galaxiesLy alpha/UV emission in distant galaxies
Lemoine-Busserolle et al. 2003Pello et al. 2003
Lensed galaxies :
Z = 2.5 1.7 2.7
Le Borgne et al.
AC114-S2
AC114-S2
AC114-S2
Local starbursts SED fitting to constrain SFR history, age of stellar population, E(B-V), metallicity
Ly alpha/UV emission in distant galaxiesLy alpha/UV emission in distant galaxies
Le Borgne et al.
SED fitting to constrain SFR history, age of stellar population, E(B-V), metallicity
Metallicity constraints from UV slope β
extinction corrected SED
UB
V
R
IJ
Kz~1.7 lensed galaxy
Ex.: Schaerer & Verhamme 08, modeling Lyman alpha line in Ex.: Schaerer & Verhamme 08, modeling Lyman alpha line in Ms1512 – cB58 (lensed LBG, z~2.7)Ms1512 – cB58 (lensed LBG, z~2.7)
Ly alpha emission in distant galaxiesLy alpha emission in distant galaxies
The size of high-z star-forming galaxiesThe size of high-z star-forming galaxies
From Bouwens & Illingworth 09
~L* galaxies
The size of high-z star-forming galaxiesThe size of high-z star-forming galaxies
From Bouwens & Illingworth 09
3 arcsec
Z~6 dropouts in the HUDF
The size of high-z star-forming galaxiesThe size of high-z star-forming galaxies
From Rauch et al. 08
Z~2.7-3.7 Ly a emitters
2D spectra
Lambda~5000 A
15 arcsec
40 A
1 arcsec1 arcsec
0.1 arcsec0.1 arcsec
0.01 arcsec0.01 arcsec
0.001 arcsec0.001 arcsec
galaxiesgalaxies
1 arcsec1 arcsec
0.1 arcsec0.1 arcsec
0.01 arcsec0.01 arcsec
0.001 arcsec0.001 arcsec
galaxiesgalaxies
bulgesbulgesSpiral armsSpiral arms
GlobularGlobularclustersclusters
HII regionsHII regions
Paladini et al. 04
Urry & Padovani, (1995)
Jets
BH
Obscuring torus(200-800K, ~1-300 pc)
NB region(T
eff ~ 60K)
BL region(T
eff~ 2000 K, ~0.1-0.01 pc)
Accretion disk(T
eff ~ 105 K, ~0.01 pc)
θ
1 arcsec1 arcsec
0.1 arcsec0.1 arcsec
0.01 arcsec0.01 arcsec
0.001 arcsec0.001 arcsecAGNAGNobscuring torusobscuring torus
galaxiesgalaxies
bulgesbulgesSpiral armsSpiral arms
GlobularGlobularclustersclusters
AGNAGNaccretion disk (~0.01 pc)accretion disk (~0.01 pc)
HII regionsHII regions
Conclusions (I)Conclusions (I) FI should be able to yield a HR UV (restframe) picture of the local
universe. Study of photoionization regions: structure (high dynamics), physics (line diagnostics -stellar, ISM-, stellar populations, ...).
UV-calibrated Star Formation Rate measurements
UV-calibrated indicators for extragalactic physics in the distant universe (metallicity, age of underlying stellar populations, IMF?, ...)
Lyman alpha properties in local starbursts. Scape fraction as a function of relevant parameters ==> High-z universe
Unprecedented capability in understanding star-formation processes at HII-region's scale.
Understanding co-evolution AGN <===> host galaxy. Nuclear regions of galaxies: looking for AGN signatures in the core region, constraining AGN feedback ...
Conclusions (II)Conclusions (II) Depending on sensitivity, FI could provide the UV budget of star
formation in galaxies from z~0 to z~2 (universe aged of 3.342 Gyr). Understanding the downsizing mechanism at the spatial scale
corresponding to a typical HII region up to z~2, and a well suited FOV(ex. FOV(z~1-2)~ is ~70 kpc; FOV(z~0.5)~50 kpc, and ~32 kpc at z~0.3).
Lyman alpha emission in details: mechanism and geometry of SF activity
Metallicity evolution for different galaxy environments.
Other interesting cases requiring high dynamic range: multiple-imaged QSOs (FVO~1-3''); clusters of galaxies (cluster core, AGN feedback, FVO~1-10'').
Tentative topic: looking at new-born galaxies at all z. This means looking for PopIII signatures (e.g. HeII1640 line) in (compact/ small/ BCGs) galaxies.
Open questions:Open questions:
The band-pass is relatively narrow (e.g. ~70A in the UV and ~450A in the near-IR at ~8000A in the imaging mode):
==> Sensitivity issue in the continuum detection (usual BB filters are ~5-10 larger in the UV)
==> For a given configuration, and for a given spectral feature, only a small redshift domain is accessible : dz~0.05(1+z)Ex. In the local universe, for the first UV band, we can reach ~2d(Coma) for a given spectral feature (e.g. Ly a).
The spatial resolution decreases with lambda, i.e. as (1+z) for a given spectral feature ==> In practise, most studies with strong requirements in spatial resolution will be limited to the « nearby » universe (z<1).
The endThe end