Dust obscured star formation in high redshift clusters

Santos et al 2013a, MNRAS in press
Santos et al 2013b, in prep.
Joana S. Santos
Tracing cosmic evolution with galaxy clusters - Sesto, IT - July 1-5 2013
B. Altieri, I. Valtchanov, I.P.Castro (ESA), V. Strazzullo (CEA), M. Tanaka (NAOJ),
A. Saintonge, P. Popesso, S. Berta (MPE), P. Rosati (ESO), K. Tadaki(NAOJ) + many others ....
Dust obscured star formation
in High-redshift clusters
Thursday, July 4, 2013

Introduction
One of the main problems of modern
astrophysics is the lack of a detailed
understanding of galaxy evolution in a
cosmological context.
The star formation rate of galaxies in
different environments & across cosmic
time is one of the key observables to
understand their evolution.
2
Magnelli + 2011
ULIRG, LIR>1012L☉
LIRG, LIR=1011-12L☉
normal

Introduction
One of the main problems of modern
astrophysics is the lack of a detailed
understanding of galaxy evolution in a
cosmological context.
The star formation rate of galaxies in
different environments & across cosmic
time is one of the key observables to
understand their evolution.
2
Magnelli + 2011
Infrared SF in (high-redshift) clusters
Infrared Space Observatory: in intermediate z clusters most of the SF is obscured (Duc + 2002)
Spitzer/MIPS: increase of dusty SF galaxies from z=0.3 to z=0.8 (Saintonge + 2008)
-> however, using only one point (24µm) to extrapolate the total IR luminosity can be dangerous...
Reversal of star formation - density relation: when, where ? (Tran + 2010)
Large uncertainty on the evolution of SFR, parametrized as (1+z)2 - 7, clear lack of ULIRGs at low-z
ULIRG, LIR>1012L☉
LIRG, LIR=1011-12L☉
normal

HERSCHEL
Herschel Space Observatory
Pilbratt +2010
PACS 70-100-160 µm
SPIRE 250-350-500 µm
HIFI 157 - 650 µm
3
Elbaz +2010

HERSCHEL
PACS (shallow) + SPIRE sample of 8 (proto)clusters
Guaranteed Time 1 PI Altieri
Seymour+ 2012 -PKS1138, Pintos-Castro+ 2013, Valtchanov+ 2013 subm.
PACS (deep): 8 X-ray clusters 1.4 < z < 1.8
Open Time 1 PI Popesso Santos + 2013
SPIRE: 4 proto-clusters 2 < z < 4
Open Time 2 PI Altieri
PACS (very deep) + SPIRE: XMMUJ0044 at z=1.6
DDT PI Santos
(proto-) Cluster z
RXJ1257.2+4738 0.86
CLJ1226.9+3332 0.89
WARPJ1415+3612 1.03
RXJ0848.9+4452 1.27
XMMUJ22353-2557 1.39
XMMUJ0044.0-2033 1.58
CLG0218.3-0510 1.62
Spiderweb 2.16
J2142‐4423 2.38
LBG-2377 3.01
TX_J1908+7220 3.53
4C41.17 3.79
4C60.07 3.79
Pilbratt +2010
PACS 70-100-160 µm
SPIRE 250-350-500 µm
HIFI 157 - 650 µm
3
Elbaz +2010

HERSCHEL
PACS (shallow) + SPIRE sample of 8 (proto)clusters
Guaranteed Time 1 PI Altieri
Seymour+ 2012 -PKS1138, Pintos-Castro+ 2013, Valtchanov+ 2013 subm.
PACS (deep): 8 X-ray clusters 1.4 < z < 1.8
Open Time 1 PI Popesso Santos + 2013
SPIRE: 4 proto-clusters 2 < z < 4
Open Time 2 PI Altieri
PACS (very deep) + SPIRE: XMMUJ0044 at z=1.6
DDT PI Santos
(proto-) Cluster z
RXJ1257.2+4738 0.86
CLJ1226.9+3332 0.89
WARPJ1415+3612 1.03
RXJ0848.9+4452 1.27
XMMUJ22353-2557 1.39
XMMUJ0044.0-2033 1.58
CLG0218.3-0510 1.62
Spiderweb 2.16
J2142‐4423 2.38
LBG-2377 3.01
TX_J1908+7220 3.53
4C41.17 3.79
4C60.07 3.79
Pilbratt +2010
PACS 70-100-160 µm
SPIRE 250-350-500 µm
HIFI 157 - 650 µm
3
Elbaz +2010
Caveat for high-z cluster studies w/ Herschel:
poor angular resolution and sensitivity

XMM2235 at z=1.39
J.S.Santos et al. 2013, MNRAS in press
4

XMMUJ2235 at z=1.393
Discovered by the XMM-Newton Distant Cluster Project in a 10ksec XMM
obs. Mullis + 2005
One of the most massive, distant clusters known: M=7x1014 M⨀ with very rich
multi-⋋ dataset Lidman+ 2008, Strazzullo+ 2010, Rosati+ 2009, Jee+ 2009 , Bauer+ 2011
35 spec. cluster members + ugrizJKs photo-zs
HST/ACS F775, F850
Rosati + 2009
5
2’x2’

6
RGB (250/160/100) µm PACS 100µm footprint + ancillary data
X2235: data
15‘x15’

Sample of 13 cluster members
6 spec + 7 photo-z members
Chary & Elbaz 2001 templates
LePhare code
Salpeter IMF
K-band 8µm 100µm 160µm
7
Caveats:
contamination
only sensitive to
SFR > 70(100) M⨀/yr
X2235: FIR SED fitting
SFR (M⨀/yr) = 4.5 x 10-44 LIR (erg/s)
Kennicutt 1998
90 < SFR < 460 M⨀ /yr

X2235: sSFR - M* relation
With stacking
we reach the
main sequence
2/3 ULIRGs
1/3 LIRGs
Striking
difference relative
to low-z clusters
that have almost
no ULIRGs
8
Main Sequence
StarburstM* from optical/NIR SED

X2235: SFR vs radial distance
Cluster core quenched: no SF at r < 250 kpc
Bauer + 2011, Gruetzbauch + 2012 from Hα narrow band imaging
9

Most SFIR happens at r>1 Mpc
-> infalling regions
(Rvir ~ 1.2 Mpc)
9

Most SFIR happens at r>1 Mpc
-> infalling regions
(Rvir ~ 1.2 Mpc)
9
Extinction: 2-3 mag AHα

X2235: SF Galaxy Morphology
Visual classiﬁcation
only possible with HST
Late-type galaxies
Disturbed morphology
Mergers <-> Starburst
10

CLG0218 at z=1.62
preliminary workSantos et al. in prep
11

CLG0218 at z=1.62
Discovered as an overdensity of red galaxies in Spitzer Papovich + 2010 and
in XMM-Newton data as weak X-ray extended emission Tanaka + 2010
Low mass “system”: upper limit ~5-7x1013 M⨀ Tanaka+ 2010, Pierre + 2011
Indications of a reversal of the SF-density relation within r<1 Mpc using
MIPS data Tran + 2010
12

CLG0218 at z=1.62
Discovered as an overdensity of red galaxies in Spitzer Papovich + 2010 and
in XMM-Newton data as weak X-ray extended emission Tanaka + 2010
Low mass “system”: upper limit ~5-7x1013 M⨀ Tanaka+ 2010, Pierre + 2011
Indications of a reversal of the SF-density relation within r<1 Mpc using
MIPS data Tran + 2010
Very deep Herschel data:
Candels + Hermes + GT1 programs
3-σ: 1.5 mJy @100µm
3-σ: 4.5 mJy @160µm
MIPS 24µm over 20x20 Mpc
study environment
Large cluster galaxy sample:
46 spec members + OII zphot emitters
hundreds zphot cluster candidates
12

CLG0218: SFR vs radius
13
Measurement of LIR: extrapolating 24um: Rujopakarn 2013 approach using
Rieke 2009 SED templates -> overcome the mid-IR excess
A few galaxies have the full FIR Herschel SED -> independent measure of SFR
Chabrier IMF

CLG0218: SFR vs radius
13
Measurement of LIR: extrapolating 24um: Rujopakarn 2013 approach using
Rieke 2009 SED templates -> overcome the mid-IR excess
A few galaxies have the full FIR Herschel SED -> independent measure of SFR
Chabrier IMF
Stellar mass M* bins:
Low M*: 1.5 - 5x1010 M⨀
Intermediate M*: 5-10x1010 M⨀
High M*: > 1011 M⨀
Sharp decline of SFR from the
cluster (<1 Mpc) to the
transition/infalling region
High M* behaves differently:
only 1 galaxy in cluster,
sharp peak at r~3-4 Mpc

CLG0218: the central galaxy
14
The central galaxy:
Full FIR SED (PACS+SPIRE)
LIR = 2.0x1012 L⨀
SFR = 190 M⨀ /yr (232, 24µm)
Mass = 7x1010 M*
Tdust=33±4 K
K 24um 100um 160um

CLG0218: the central galaxy
14
The central galaxy:
Full FIR SED (PACS+SPIRE)
LIR = 2.0x1012 L⨀
SFR = 190 M⨀ /yr (232, 24µm)
Mass = 7x1010 M*
Tdust=33±4 K
AGN contamination?
X-ray ﬂux = 1.33x10-15 erg/s/cm2
DecompIR Mullaney+2011
SED separation:
AGN with 9% of LIR
K 24um 100um 160um

Conclusions & Outlook
The mapping of SF in XMM2235 with Herschel shows
a distinct lack of SF in the cluster core
signiﬁcant amounts of SF in the outskirts (mostly at r > 1 Mpc)
only ULIRGS (at low-z only ULIRGs are rare in clusters)
caveat: contamination -> NIR spectroscopy required
The mapping of SF in CLG0218 with MIPS+Herschel shows
High level of SFR in the cluster (SFR24um > 20 M⨀/yr)
role of stellar mass: high M* galaxies behave differently from low M* and are
preferentially found in the ﬁeld region
central galaxy: SFR=190 M⨀ /yr, Tdust=33 K, AGN component w/ 9% LIR,
“descendant” of the Spiderweb ?
15

15
Mcluster~5x1013M☉
Lots of SF in the core, SF (r<0.5 Mpc) ~ 1220 M☉/yr /Mpc2
Continuous amount of SF in the outskirts to the ﬁeld
Mcluster~1015M☉
Low SF in the core, SF (r<0.5 Mpc) ~ 240 M☉/yr/Mpc2
Lots of SF in the outskirts / infalling region

15
Coming next:
- XMMUJ0044 at z=1.58, a massive cluster detected in X-rays (Santos + 2011)
- Near future: complete study of a sample of ~12 high-z clusters with different
environments (Pintos-Castro et al in prep.)
Mcluster~5x1013M☉
Lots of SF in the core, SF (r<0.5 Mpc) ~ 1220 M☉/yr /Mpc2
Continuous amount of SF in the outskirts to the ﬁeld
Mcluster~1015M☉
Low SF in the core, SF (r<0.5 Mpc) ~ 240 M☉/yr/Mpc2
Lots of SF in the outskirts / infalling region

Dust obscured star formation in high redshift clusters

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