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Clustering and dusty high-z galaxies. Emanuele Daddi ESO-Garching (  NOAO-Tucson). Properties of K-selected z=2 galaxies (K20/GOODS/other surveys)  dusty SF galaxies Efficient selection technique Clustering.

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Clustering and dusty high z galaxies

Clustering and dusty high-z galaxies

Emanuele Daddi



  • Properties of K-selected z=2 galaxies

  • (K20/GOODS/other surveys)

  •  dusty SF galaxies

  • Efficient selection technique

  • Clustering

How, when did massive galaxies form ? Studying clustered high-z populations

Near ir bright z 2 galaxies
Near-IR bright z~2 galaxies

K<20 at z~2  10^11 Msun

stellar masses

Too many massive galaxies

at z>1.4 as compared to

what LCDM models had


Cimatti et al. 2002, K20 survey

SFR~50—500 Msun/yr, Lya emission often absent,

red UV continua, strong absorption lines,

Irregular/merging morphologies

Daddi et al. 2004 ApJ 600 L127

Passive 1—2 Gyr galaxies,

early-type morphologies

Cimatti et al. 2004, Nature, 430, 184

Bzk selection technique
BzK selection technique

BzK=(z-K)-(B-z) (AB mags)

BzK>-0.2  SF at z>1.4

BzK<-0.2 & z-K>2.5  Old

Daddi et al. 2004 ApJ in press


94% of spec redshifts; K20 survey Technique calibrated with ~50 z>1.4 redshifts

Reddening independent selection of sf galaxies
Reddening independent selection of SF galaxies

Also because of K-selection

Calzetti et al. 2000

extinction law

Would miss <10Myr bursts

Median E(B-V)~0.4

(from CSF models)

Ungrs colors of k 20 z 1 4 sample
UnGRs colors of K<20 z>1.4 sample

BM/BX samples include K<20

sources (Shapley et al. 2004)

but miss most reddened SF

(~20--30% of total SFRD)

and passive galaxies

For K<20 sources

Density is ~ 10^-3 h^3 Mpc^-3

comparable to local L>L* gals

much smaller than LBGs

X ray stacking
X-ray stacking

(Szokoly et al 2004; Gilli et al 2004)

  • Lx~ 8x10^41 cgs

  • HR < -0.54 (2-sigma)

  • star-forming galaxies

  • <SFR> ~ 200 Msun/yr

Average 20cm radio emission also give 2-300 Msun/yr

(Courtesy of K.Kellermann, J.Kelly; VLA data)

Scuba galaxies or their remnants
SCUBA galaxies, or their remnants

6 objects:

Photometric follow-up with SCUBA

(with Rottgering, Cimatti, Kurk)

One detection 4.5mJy (850mu)

Positive flux from the others

(about 1mJy, 2.5 sigma)

(preliminary numbers)

 Bridge to submm/mm populations ?

More time allocated SCUBA/IRAM (but slow going…)

Need Spitzer and/or future facilities to detect

dust emission, even more for dusty K>20 sources

Bzk colors to identify counterparts
BzK colors to identify counterparts ?


Dannerbauer et al.,

this conference

  • But week correlation between

  • K and submm flux, why ?

  • week SFR/Mass correlation ?

  • redshift effects ?

  • Large/variable obscuration even

  • at K ?

Forming progenitors of massive early type galaxies detected
Forming progenitors of massiveearly-type galaxies detected ?

  • Large masses, near-IR bright (K<[email protected]~2)

  • Large SFRs (SFR>100 Msun/yr)

  • Metal enriched (Solar or more)

  • Density comparable to z=0 L>L* galaxies

  • Assembling by merging, perhaps some

    Are these strongly clustered ?

Evidence for clustering
Evidence for clustering

Enhanced clustering of

z~2—3 K-sel galaxies

from FIRES, Daddi et al. 2003

Redshift pairings in the (SMALL)

spectroscopic samples: e.g.

Daddi et al. 2004; van Dokkum et al 2003

Monte Carlo simulations

of clustered samples:

r_o > 7 h^-1 Mpc (95% c.l.)

Needs much larger sample

to measure clustering

Eso japan collaboration
ESO—Japan collaboration:

ESO: Renzini, Cimatti, Mignoli,

Pozzetti, Zamorani, Brusa, ED

Subaru: Arimoto, Ikuta, Kong,

Onodera, Ohta, etc

450 z>1.4 candidates BzK-sel

350 arcmin^2 field to K=20

(Kong et al. in preparation)

~ 300 spectra taken with VIMOS

Gmass eso lp on udf k20 goods region

PI: A. Cimatti

145 hours FORS2


Collaboration with GOODS


IRAC 4.5mu<23.5 AB

zphot>1.4, BzK

50 arcmin^2 region

raw+reduced data will be

publicly released

Goods cdfs

BzK selection to K=22 Vega

(incomlete for reddest objs)

VIMOS public observations:

~1000 BzKs

(plus ~1000 UV-sel objects)

PI: C. Cesarsky

Catalogue by L.Moustakas, B.Mobasher, M.Dickinson, et al.

Cosmos bzks 2 square degree 20000 bzks
COSMOS BzKs: 2 square degree, ~20000 BzKs

Submitted ESO LP (>500n)

PI: S.Lilly

10000 BzKs to be observed

+ 20000 UV-sel objects

Catalogue Subaru+KPNO

B.Mobasher, Y.Taniguchi,

N.Scoville(PI) H.Aussel,


Angular clustering
Angular clustering

About 450 K<20 z>1.4 candidates; ESO/Japan obs of EIS Deep3a field




r_o ~ 8+-2 h^-1 Mpc (fixed delta=0.8)

from Limber equation (main uncertainty N(z))

for BzK-SF

BzK-Old seem to have higher angular clustering

Preliminary cosmos results
Preliminary COSMOS results

A(1deg) ~0.008; S/N ~ 10 (fixed delta=0.8)

 r_0 ~ 10+-2 h^-1 Mpc (main uncertainty N(z))

Evolution m 10 11 msun l l galaxies
Evolution: M>10^11 Msun (L>~L*) galaxies

Tracks: evolution of DM halos from

Mo & White 2002

  • dusty z~2 K-bright galaxies consistent to evolve into EROs and local gEs

    clustering comparable to SCUBA objs (Blain et al. 2004), higher density

    LBGs have r_o~4 h^-1 Mpc (Adelberger et al 2005)

Gif models jenkins et al 1998 kauffmann et al 1999
GIF Models (Jenkins et al 1998; Kauffmann et al. 1999)

  • Correctly predict that at z>1.4

  • objects with 10^11 Msun

  • stellar mass are either old/dead

  • or very active starbursts

  • AND classify the active starbursts

  • as early-type galaxies (bulge

  • dominated, red)

  • Agree with our conclusion that

    near-IR bright z>1.4 objects

    evolve into massive E/S0s

  • (but predict x10 too few objects)


  • Population of massive dusty SF galaxies at z~2: bridge between

    submm/mm and LBGs, forming L>~L* early-type galaxies

  • BzK selection is very efficient for 1.4<z<2.5  reddening independent selection of SF galaxies

  • Clustering is an important measure for dusty high-z galaxies

    (link to evolution, DM halos properties, etc). Requires statistics

    (N_objs), wide/many fields, redshifts for high significance measurements

Passive BzKs in UDF

Daddi et al 2005 (in preparation)

ACS+HST spectra from

GRAPES project (PI Malhotra)


Average uv spectra de mello et al 2004 apj 608 l29
Average UV spectra: de Mello et al. 2004 ApJ 608 L29

NGC 6090: Merger, dusty, LIRG, metal rich