Star formation histories

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Star formation histories and environment

Bianca M. Poggianti INAF Osservatorio
Astronomico di Padova

• WE ARE ALL AFTER THE BIG PICTURE
• To what extent, environment
• To what extent intrinsic/galaxy mass or else
• 2) When environment, what physical mechanism
  (hence, where when)

2
How to measure environment? One way is to
measure the local galaxy density
MORPHOLOGY-DENSITY RELATION in clusters
Number of neighbours, brighter than a certain mag
limit, per unit of projected area or
volume Observationally rather easy, even with
just photometry
Fraction of galaxies
S0
Spirals
E
projected surface density (log)
Dressler 1980, as in Dressler et al. 1997
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Another way is to measure the mass of the host
structure (cluster and group)
Cluster velocity dispersion X-ray luminosity
Cluster total luminosity/richness Weak-lensing Su
nyaev-Zeldovich
Optical luminosity
X-ray luminosity
Virial mass
Popesso et al. 2005
Location in a cluster, group, filament, void In
clusters, clustercentric distance (with respect
to virial or stripping radius), substructure
etc .usefulness of single, very well studies
cases where physics becomes evident
Limitation of general field studies until
recently dont discriminate environment
(groups/isolated) so the evolution in the
field could be driven by the growth of structure
(environment) - now starting (DEEP2, zCOSMOS etc)
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OUTLINE

• StarFormation and Local Density
• StarFormation and Cluster/Group Mass
• Evolution of the StarFormation in Clusters (red
  sequence, blue/emission line galaxies,
  post-starburst galaxies)
• Star Formation and Galaxy Morphology
• the big picture (?)

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IMPORTANT TO ASK TWO SEPARATE QUESTIONS

• The fraction of star-forming (or passive)
  galaxies
• Often this is done checking blue vs red fraction
  
• Butcher-Oemler effect ---- red sequence build-up

Quantify the evolution of red as a function of
environment
b) SFR in SFing galaxies depends on environment?
If not, either changes are intrinsic
(NOT-environmentally driven) OR changes are
abrupt/fast
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The evolution of the star formation-density
relation
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Galaxy stellar mass function itself varies with
density
Mass fraction per dex
Log M (stellar mass)
Low-z SDSS Baldry et al. 2006 Bundy et al. 2006
DEEP2 Simon Lillys talk zCOSMOS and posters
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Low redshift
Red galaxy fraction depends on both local density
and galaxy stellar mass
Local density
Galaxy mass
SDSS Baldry et al. 2006, also Kauffmann et al.
2004
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The red galaxy fraction-density relation at
higher-z
0.4ltzlt0.75
0.75ltzlt0.85
0.85ltzlt1.0
1.0ltzlt1.3
Galaxies turning from blue to red preferentially
in overdense regions (groups??) at z below 1.5
the establishment of the SFing fraction-density
relation at z 1.5-2 ? (More massive
environments, higher-z clusters are the tail of
a distribution)
DEEP2 Cooper et al. 2007, Gerke et al. 2007 VVDS
Cucciati et al. 2006
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Low redshift
So, the SF-ing depends on density. The SF in
SF-ing galaxies doesnt ?
Fraction of galaxies
Halpha equivalent width
Balogh et al. 2004a
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WHAT CHANGES WITH ENVIROMENT IS ONLY THE
STARFORMING FRACTION (higher-z)?
Color-mass diagram, at different local densities
Z 0.7
COSMOS Cassata et al. 2007 also Noeskes 2007
Letters
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STAR FORMATION-LOCAL DENSITY RELATION
Clusters at z0 0.4-0.8
?
Star-forming fraction
Mean(EW) of OII galaxies
Local density
Local density
Black z0.4-0.8 (ESO Distant Cluster Survey) Red
z0.04-0.08 (SDSS clusters)
Poggianti et al. 2008
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Average SFR per galaxy vs density field at z1
The relation between the average star formation
rate per galaxy and the local density is reversed
compared to the local Universe . (is it?)
Z1
Z1
Z0
higher density
Cooper et al. 2008
Elbaz et al. 2007
And for just star-forming galaxies? With same
mass distributions?
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Clusters groups at z0.4-0.8 Average SFR vs
density (sSFR same way)
Seems to imply the SFR in SF-ing galaxies depends
on density while the EW-density relation seems
to imply it doesnt
All galaxies (black) SFing
galaxies (blue)
ESO Distant Cluster Survey Poggianti et
al. 2008
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The evolution of the star formation activity as
a function of cluster/group mass
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The oldest galaxies at any redshift
Color-Magnitude sequence zero-point, slope and
scatter consistent with passive evolution of
stellar populations formed at zgt2-3 (Bower,
Ellis, Kodama). Fundamental plane,
mass-to-light ratios and Mg-sigma relation,
bright-end of K-band (mass) luminosity function
ACS team Z0.8-1.3 Mei et al. 2008
Z 1.24
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STAR FORMATION DOWNSIZING the cluster view
U-V color
Red sequence faint-to-luminous ratio
V absolute magnitude
0.0 redshift 1
A deficiency of red galaxies at faint magnitudes
in distant clusters compared to nearby
clusters. Most massive galaxies are the first
ones to conclude their SF activity - The more
massive, the older their stellar populations,and
the higher the redshift of their last SF
De Lucia et al. 2004, 2007, Kodama et al. 2004,
Stott et al. 2007, Tanaka et al. 2005, but
Andreon 2008
Kodamas talk
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STAR FORMING FRACTION vs z IN CLUSTERS
0.0 z 0.5

Fraction of blue galaxies versus
redshift Butcher-Oemler 1984, Kodama Bower 2001

Spectroscopy confirmed a widespread SF activity
in z0.4-0.5 clusters Star-forming fraction
30-50, compared to nearby similar clusters that
contain few galaxies with ongoing or recent SF


Dressler Gunn 1982, 1983, Couch Sharples
1987, Poggianti et al. 1999, Dressler et al.
1999, Ellingson et al. 2001, Balogh et al. 1997.
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Trends with cluster/group mass low-z
Richer, more centrally concentrated, relaxed
clusters have fewer star-forming/late-type
galaxies. Early attempts with (e.g. Zabludoff
Mulchaey 1998, Biviano et al. 1997) and without
(e.g. Smail et al. 1998, Andreon Ettori 1999)
success. But hard to quantify
Fractions of galaxy types versus system mass
(vel.dispersion)
12 15 log M

Weinmann et al. 2006
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Trends with system mass at low-z II
Red galaxy vs sigma
Blue galaxy vs sigma
Goto 2005 also Tanaka et al. 2004

Balogh et al. 2004
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Evolution of the of SF-ing galaxies

EDisCS z 0.4-0.8
Sloan z 0.04-0.1
Fraction of members with OII within R200
1000
500
1000
500
Velocity dispersion
OUTLIERS!
ESO Distant Cluster Survey Poggianti et al.
2006
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Evolution of the star-forming fraction
Change in star-forming fraction between 20 and
50 - stronger in lower mass systems How are
these trends established? Note that the low-z
trend HAD break at some sigma, otherwise the
field today would be like the clusters/groups. A
universal 3 X 1012 halo mass threshold for
quenching (within 3Gyr from infall) produces far
too few starforming galaxies in clusters of any
sigma today!
Poggianti et al. 2006
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How do galaxies turn from star-forming to passive
in clusters, and why well studied, individual
clusters
Evidence for enhancement slow decline sudden
truncation
Cl0024 and MS0451 at z0.4
starvation
truncation
Small bursts at virial radius Slow conversion of
spirals to S0s in infalling groups in the
outskirts (gentle gal.-gal. Interactions?)
additional fast truncation mechanism in inner
regions (ram pressure? where ICM dense)
Harassment, ram pressure and starvation?
Moran et al. 2005, 2006, 2007a,b,c
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A quenching timescale dependent on galaxy mass
Dusty red galaxies logM10-11, low mean
specific star formation rate (dust reddened),
indicating quenching is slow (see also Goto et
al. 2003) but could it be just that are more
massive are earlier-type galaxies? In lower
mass galaxies, fast quenching accompanied by
morphological change (no cluster-specific red
spirals phenomenon at logMlt10)
Log SFR/M
STAGES Wolf et al. 2009 Also Haines et al. 2006,
2007
logMass
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If a truncation mechanism acts fast, it leaves
a clear signature. post-starburst galaxies
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POST-STARBURST SPECTRA IN DISTANT CLUSTERS
(z0.4-0.5)

strong Balmer absorption and no line detected in
emission
SF ended abruptly sometime during the last Gyr

post-starburst galaxies 25 of the
distant cluster galaxy population Dressler
Gunn 1983, Couch Sharples 1987, Dressler et al.
1999, Poggianti et al. 1999, Tran et al. 2001,
2004
Larger in clusters than in field at similar zs
(Dressler et al. 1999, Poggianti et al. 1999,
Tran et al. 2003,2004, now Ediscs, Ma et al
but Balogh et al. 1999) SF truncation in
clusters
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At z0.4-0.8, post-starburst galaxies more
frequent in more massive clusters and in some of
the groups
Ka fraction
those groups with a low OII fraction for their
sigma
EDisCS Poggianti et al. 2009
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Post-starburst downsizing in clusters
In the Coma cluster Rare among bright galaxies,
but common (15) among dwarfs (Poggianti et al.
2004) Evidence for ICM origin In Coma,
associated with X-ray substructure, pointing to
impact with ICM shock fronts (Poggianti et al.
2004). In cluster at z0.5, post-starbursts
within the (projected) ram pressure stripping
radius (Ma et al. 2008)
Mv - 18
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Post-starburst fractions among bright field
galaxies
Rare at all redshifts (Zabludoff et al. 1996,
Goto 2005, Yan et al. 2009)
In the field at z0, mostly associated with
mergers (Zabludoff et al. 1996, Yang et al.
2004, 2008, Goto 2005, Nolan et al. 2007).
Confirmed by spectroscopy of companions (Goto
2005, Yamauchi et al. 2008, also Goto et al.
2008)
AGN and SN feedback above/below 1010 Msun
descendants of LIRGs and ULIRGs (Kaviraj et al.
07) Evolution of frequency also in the field a
factor of 230 between 0.07 and 0.7 (Wild et al.
2009)
Highly probable different origin in different
environments
How relevant for the evolution of the
star-forming fraction and of the cosmic SF
history? Open question (eg Yan et al. 2009 vs
Wild et al. 2009 40 of red sequence growth
rate)
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GROUP BIMODALITY ? THE KEY?
Evidence some groups look like mini-clusters,
some look like field (at the same mass) for
their star forming fraction, morphologies,
post-starburst incidence etc Poggianti et al.
2006, 2008, 2009a, Wilman et al. 2005, 2009,
Kautsch et al. 2008, Jeltema et al. 2007 also
Zabludoff Mulchaey 1998. Not simply true vs
false groups? (eg. X-ray groups Jeltema et al.
2007 Rasmussens talk) hard to explain as wrong
mass estimate Difference between two types of
groups ought to help to understand what is going
on at the group level
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Red sequence build-up from secular SF histories
Irr Sd Sc Sb Sa S0 E
Fritz et al. In prep.
Log stellar mass (Msun)
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Star formation and galaxy morphology (Hubble
type)
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MORPHOLOGICAL EVOLUTION IN CLUSTERS from spiral
to S0 GALAXIES
S0
Elliptical
SpiralIrr
Desai et al. (2007)
(Dressler et al. 1997, Fasano et al. 2000,
Postman et al. 2005, Smith et al. 2005 but also
Andreon et al. 1998, Holden et al. 2009)
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Evolution of the morphological fractions
AGAIN, EVOLUTION IS STRONGER IN LESS MASSIVE
CLUSTERS!! also Wilmans talk, Kautsch et al.
2008 for S0s in groups (and Dressler 1980)
Wide-field Nearby Galaxy-cluster Survey (WINGS)
Poggianti et al. 2009 ApJ Letter
Also Dennis Justs poster
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WINGS database
Wide Field (35, R500 in all) Sample 76
clusters, complete in LX 0.04ltzlt0.07
Optical Imaging (BVWINGS-OPT) WFC_at_INTWFI_at_ESO2.2
Fiber Spectroscopy (WINGS-SPE) 48
clusters WYFFOS_at_WHT2dF_at_AAT
NIR Imaging (JK WINGS-NIR) 28
clusters WFCAM_at_UKIRT
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WINGS database Astro Pizza - Padova 4 Feb. 2009
U-band 18 clusters WFC_at_INT90_at_BokLBC_at_LBT
(almost completed) Ha narrow-band few
clusters so far WFC_at_INT (ongoing) BV, Very
Wide-Field 50 clusters OmegaCam_at_VST (planned)
Follow-up imaging
GASPHOT automated surface
photometry MORPHOT automated
morphological classification SIMSPEC
SFHs and stellar masses
AD HOC Software
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Wings Catalogs
Optical photometry (Fasano et al. 2006, Varela
et al. 2009 in press) Near-IR catalogs release
(Valentinuzzi et al. 2009 in press) Spectroscopi
c catalog release (Cava et al. 2009 in
press) Line measurements and star formation
histories (Fritz et al. 2009a in prep., 2009b
in prep.) Morphology and sur. phot.
catalogs (Fasano et al. 2009, in prep., DOnofrio
et al. in prep.) Lick Indices Release (Hansson
et al. 2009 in prep.) UV catalogs
release (Omizzolo et al. 2009, in prep.)
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FORMULATING A WORKING HYPOTHESIS
FROM BLUE TO RED ON A COSMIC SCALE either it
happens in groups, or it is intrinsic but it
cannot happen in all groups, as testified by the
large scatter in galaxy properties in groups
so, hard to be explained by strangulation
What if what really matters is the primordial
matter density (primordial environment, if you
like) AND the primordial available mass That
correlates with the distributions of
local projected future density
global environment galaxy mass
additional mechanisms on some galaxies required
(eg. post-starbursts) is there ANY evidence
that a group-specific mechanism (strangulation)
is needed?? How different from common picture?