Disentangling Luminosity, Morphology, Stellar Age, Star Formation, and Environment in Galaxy Evolution Daniel Christlein Andes Fellow Yale University & Universidad de Chile & Ann Zabludoff (U Arizona) ? = Kant : Systems of Fixed Stars, Arrangements of Worlds, Worlds of Worlds, Milky Ways of Worlds Island Universes
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Disentangling Luminosity, Morphology, Stellar Age, Star Formation, and Environment in Galaxy Evolution
Kant : Systems of Fixed Stars, Arrangements of Worlds, Worlds of Worlds, Milky Ways of Worlds. Island Universes. Disentangling Luminosity, Morphology, Stellar Age, Star Formation, and Environment in Galaxy Evolution. Daniel Christlein Andes Fellow Yale University & Universidad de Chile & - PowerPoint PPT Presentation
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Disentangling Luminosity, Morphology, Stellar Age, Star Formation, and Environment in Galaxy Evolution
Daniel Christlein Andes Fellow
Yale University & Universidad de Chile &
Ann Zabludoff (U Arizona)
?=
Kant: Systems of Fixed Stars, Arrangements of Worlds, Worlds of Worlds, Milky Ways of Worlds
Island Universes
We know some basic statistics about galaxies:
- Luminosity Function
- Morphology-Environment Relation
- Star Formation-Environment Relation
but understanding incomplete:
-environmental dependence of LF?
-origin of morphological sequence?
-Nature or Nurture?
< Binggeli, Sandage & Tamman 1988
The Data- 6 nearby (z<0.07), rich clusters
- R-band photometry
- spectroscopy for ~3000 galaxies:
star formation indices, stellar age indices
- 2MASS J-, K-photometry -> stellar mass
- quantitative morphology with GIM2D (Simard 2002)
- new ML algorithmAbell 1060
Christlein & Zabludoff (2003)Is Luminosity Function Dependent on Environment?
● field and cluster overall GLFs same
● no difference for star-forming galaxies
● GLFs for quiescent galaxies steeper in clusters
X
● steepening of quiescent LF ●difference between field and groups, not groups and clusters
Which Environments Shape the GLF?
Which Environments Shape the GLF?
GLFs are pretty uniform in clusters (>60%, >40% for NEL)
all galaxies quiescent galaxies
- the high-mass end
● quiescent GLF● dwarf/giant ratio● uniformity of GLF in clusters● 2dF & SDSS: break in SFR● cD < 400 km s-1
● gE in subclumps ● early type fraction ● HI deficiency in groups
many saturation points:
=> Groups are where it's at! Gomez et al.
Lewis et al.
Are Groups the Most Important Environments?
x
● quantify morphology by bulge fraction (B/T; GIM2D)