GALaxy Evolution eXplorer GALEX

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GALaxy Evolution eXplorer( GALEX )
PI Chris Martin
Institutes Caltech LAM JHU UCLA CIW UCB Yonsei
Univ. MPI

• Stéphane ARNOUTS

EFIGI IAP 29 Nov 2004
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GALEX Mission
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GALEX has a wide-field of view and uses a
large-format photon-counting detector
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M101
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Z0.2
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AIS fields
Texp100-300 sec
Poisson distribution with Low Counts
FUV
NUV
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Z0.5
Z0.2
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Z1.5
Z0.5
Z0.2
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M51 Whirlpool GalaxyWavelength Comparison
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Rest UV Traces Star Formation
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M31 UV vs. Optical
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IRAS
2MASS
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Rest UV Traces Star FormationIn Disks w/ Strong
Driving Dynamics
1 orbit 1500 sec
GALEX
DSS
NGC1512
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Rest UV Traces Star FormationIn Disks w/ Weak
Driving Dynamics
1 orbit 1500 sec Limit 27.5 mag/sq.
NGC300
Visible DSS
Ultraviolet GALEX
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UV Traces Star Formation Region

• GALEX provides the local calibrations of
• Star forming galaxy properties
• (dust attenuation, morphology,)
• Z0 0.15-0.25 ?m (FUV - GALEX)
• To be directly compared with high-z sample
• Z2 - 3 0.45-1.00 mm (Opt. - HST /
  CFHTLS)
• Z4 - 6 0.75-1.75 ?m (NIR - ISAAC /
  WIRCAM)

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Rest UV Traces Structure FormationImage of
Merging Subunits at z3??
Z0 0.15-0.25 ?m (FUV)
0.55?m (Opt.) Z2
0.45-0.75 mm (Opt.)
1.65 mm (NIR) Z3 0.60-1.00 mm
(Opt.) 2.20 mm (NIR)
One Unit ?
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GALEX Data Release
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GALEX resolved Galaxy Sample
NGS/MIS/DIS in IR0.2 Gal. with Øgt2 300
(Gil de Paz, Boissier et al) RC3 with Øgt2
3000
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Early Type Galaxy sample
RC3 -6lt Type lt 0 MIS/DIS in IR0.2 129 (Donas
et al)
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Star Formation in cluster environments
Virgo Cluster Early Types
NGC 4551 E
(Boselli et al.)
NGC 4473 E0
NGC 4458 E0-1
NGC 4550 SB0
NGC 4497 SAB0
NGC 4436 dE6
NGC 4440 SBa
NGC 4431 SA0
NGC 4461 SB0
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GALEX-CDFSFUV band (1500Å)
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GALEX-CDFSNUV band (2300Å)
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GALEX-CDFSB band (4500Å)
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Rest UV measures SFH EvolutionLuminous UV
galaxies to z1 (Zamojski, DS)
All images Rest B band
Morph. Transformation?
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Blending issues
How to distribute the flux between the components
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Magnitude limited sample ?
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Blending issues
One dominant source
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Blending issues
The closest is the wrong one
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Blending issues
Use of the color information or SED
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GALEX-VVDS matches in F02
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Blending in UV fluxes

• Closest optical
• Pure geometric approach (no color dependance)
• Pure color approach (NUV from optical
  color)
• geometric color or photo-z information

• Profile fitting approach from
• Optical sources GALEX-PSF -gt GALEX sources

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Matching GALEX-VVDS in F02
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Blending in UV fluxes
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Rest UV Surveys Find Rare ObjectsLyman Break
Galaxies at z0?
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UV continuum SFR Simple Stellar Population
Age 1 Myr Young Massive O, B stars
Bruzual and Charlot (2003)
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UV continuum SFR Simple Stellar Population
Age 10 Myr Most massive stars off MS Red
supergiants
Bruzual and Charlot (2003)
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UV continuum SFR Simple Stellar Population
Age 0.1-1 Gyr B, A, F stars Prominent Balmer
lines and 3646 A break AGB stars dominate IR
Bruzual and Charlot (2003)
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Performance Summary
Im
Im
Sp
Sp
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Rest UV Traces Star FormationIn Tidal Tails
formed by Interacting Disks
NGC 5713
NGC 5719
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Rest UV Traces Gas MetalsDust
Infrared SSC ERO
Ultraviolet GALEX
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M81 UV vs 7 mm
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UV detects Star Formation in the local universe
M101
FUV 1540 A
NUV 2310 A
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Rest UV Traces Star FormationIn Disks with
Extended Star Formation
M83
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Photons to Images
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Rest UV Traces Star Formationon complementary
timescales w.r.t Ha, IR, Radio
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M33 Halpha GALEX scale 6-18pc
No SDSS, but other superb corollary imagery.
Unbeatable resolution and vantage point.
Massey et al. 2003 LG Survey B, V, Ha composite
GALEX NGS, one eclipse FUV, NUV composite
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Rest UV Traces Star FormationIn Merging Galaxies