inger jørgensen, gemini jordi barr, oxford roger davies, oxford kathleen flint, gemini
DESCRIPTION
The Gemini/HST Galaxy Cluster Project – Galaxy Evolution During Half the Age of the Universe Marcel Bergmann (NOAO Gemini Science Center). Inger Jørgensen, Gemini Jordi Barr, Oxford Roger Davies, Oxford Kathleen Flint, Gemini David Crampton, HIA Bryan Miller, Gemini - PowerPoint PPT PresentationTRANSCRIPT
The Gemini/HST Galaxy Cluster Project – The Gemini/HST Galaxy Cluster Project – Galaxy Evolution During Half the Age of the Galaxy Evolution During Half the Age of the
UniverseUniverse
Marcel BergmannMarcel Bergmann(NOAO Gemini Science Center)(NOAO Gemini Science Center)
Inger Jørgensen, GeminiJordi Barr, OxfordRoger Davies, OxfordKathleen Flint, GeminiDavid Crampton, HIABryan Miller, GeminiMarianne Takamiya, UH-Hilo
Abell 851 z=0.41
Science ObjectivesScience Objectives● Star formation history in rich clusters of Star formation history in rich clusters of
galaxiesgalaxies● As a function of galaxy massAs a function of galaxy mass● As a function of redshiftAs a function of redshift● Duration of star formation bursts; galactic Duration of star formation bursts; galactic
winds; IMF variationswinds; IMF variations● MethodsMethods
● Scaling relations Scaling relations ● Fundamental Plane Fundamental Plane ● velocity dispersion – absorption line velocity dispersion – absorption line
strengthsstrengths● With the use of models: Determine With the use of models: Determine
luminosity weighted mean ages, [M/H], [luminosity weighted mean ages, [M/H], [/Fe]/Fe]
Summary & ConclusionsSummary & Conclusions● We are obtaining deep spectroscopy and HST imaging for We are obtaining deep spectroscopy and HST imaging for
15 clusters covering 0.2 < z < 1.015 clusters covering 0.2 < z < 1.0● Offsets in the Faber-Jackson relation are inconsistent with Offsets in the Faber-Jackson relation are inconsistent with
passive evolution models having zf > 2 for Abell 851 and passive evolution models having zf > 2 for Abell 851 and RXJ0142.0+2131.RXJ0142.0+2131.
● Line index analysis for RXJ0152.7-1357 suggests that the Line index analysis for RXJ0152.7-1357 suggests that the stellar populations in these galaxies are also inconsistent stellar populations in these galaxies are also inconsistent with passive evolution because the [E/Fe] abundance with passive evolution because the [E/Fe] abundance ratios evolve.ratios evolve.
● More work is needed to produce models which can be More work is needed to produce models which can be applied to low and high z observations consistently.applied to low and high z observations consistently.
● We may be seeing hints at environmental effects within We may be seeing hints at environmental effects within the cluster on the stellar population element abundance the cluster on the stellar population element abundance ratios.ratios.
Selection of ClustersSelection of Clusters
Selection of ClustersSelection of Clusters
RXJ0152.7-1352 RXJ0142.0+2131 Abell 851
Perseus
Coma
Observational data for each clusterObservational data for each cluster
● Gemini/GMOS imaging in 3 filtersGemini/GMOS imaging in 3 filters
Observational data for each clusterObservational data for each cluster● Gemini/GMOS imaging in 3 filtersGemini/GMOS imaging in 3 filters● Gemini/GMOS spectroscopyGemini/GMOS spectroscopy
– 30-50 cluster members per cluster30-50 cluster members per cluster– 1-2 mag deeper than most previous studies1-2 mag deeper than most previous studies– Higher S/N spectraHigher S/N spectra– No morphological selection; blue galaxies No morphological selection; blue galaxies
includedincludedredshift, velocity dispersion: z, redshift, velocity dispersion: z, σσabsorption line indices: Mgb, <Fe>, Habsorption line indices: Mgb, <Fe>, Hββ (redshift < (redshift <
0.7)0.7) C4668, Fe4383, HC4668, Fe4383, Hδδ+H+Hγγ (all redshifts)(all redshifts)
● HST: ACS or WFPC2 imaging =>HST: ACS or WFPC2 imaging =>
2D photometry, effective parameters, 2D photometry, effective parameters, morphologymorphology
0.5 Mpc0.5 Mpc
H0=70 km/s/Mpc
m=0.3 =0.7
Perseus z=0.018
RXJ0152.7-1357 z=0.83
30 a
rcse
c
10 a
rcm
in
Abell 851 z=0.41
1 arcmin
0.5 Mpc
Faber-Jackson RelationFaber-Jackson Relation
•Coma
•RXJ0142.0+2131 ∆m=-0.51±0.21
•Abell 851 ∆m=-1.11±0.17
•RXJ0152.7-1357 ∆m=-0.88±0.18
∆log(age)=-0.37 zf = 4.1 (2.8 - 8.8)
Faber-Jackson RelationFaber-Jackson Relation
•Coma
•RXJ0142.0+2131 ∆m=-0.51±0.21
•Abell 851 ∆m=-1.11±0.17
•RXJ0152.7-1357 ∆m=-0.88±0.18
∆log(age)=-0.37 zf = 4.1 (2.8 - 8.8)
RXJ0142 and Abell 851 are inconsistent with passive evolution models having z
f > 2
Line Index-Line Index-σσ Relations Relations
Line Indices & SSP Line Indices & SSP ModelsModels
RXJ0152.7-1357 (z=0.83) vs. RXJ0152.7-1357 (z=0.83) vs. z=0z=0
Summary & ConclusionsSummary & Conclusions● We are obtaining deep spectroscopy and HST imaging for We are obtaining deep spectroscopy and HST imaging for
15 clusters covering 0.2 < z < 1.015 clusters covering 0.2 < z < 1.0● Offsets in the Faber-Jackson relation are inconsistent with Offsets in the Faber-Jackson relation are inconsistent with
passive evolution models having zf > 2 for Abell 851 and passive evolution models having zf > 2 for Abell 851 and RXJ0142.0+2131.RXJ0142.0+2131.
● Line index analysis for RXJ0152.7-1357 suggests that the Line index analysis for RXJ0152.7-1357 suggests that the stellar populations in these galaxies are also inconsistent stellar populations in these galaxies are also inconsistent with passive evolution because the [E/Fe] abundance with passive evolution because the [E/Fe] abundance ratios evolve.ratios evolve.
● More work is needed to produce models which can be More work is needed to produce models which can be applied to low and high z observations consistently.applied to low and high z observations consistently.
● We may be seeing hints at environmental effects within We may be seeing hints at environmental effects within the cluster on the stellar population element abundance the cluster on the stellar population element abundance ratios.ratios.
“Optical Line Indices”
“Blue Line Indices”