Diapositive 1

1
Millimeter detection of Spitzer
selected hyperluminous infrared starburst
galaxies Alain Omont (IAP) C. Lonsdale, M.
Polletta and the Swimambo Collaboration
The SWIRE Spitzer survey has detected by far the
largest set of Sub-Millimeter Galaxies (SMG) But
their identification requires validation with
(sub-)millimeter observations With MAMBO/IRAM we
detected at 1.2mm 30-40 SWIRE z2 starburst
HLIRGs with LFIR1013Lo They belong to a rather
rare subclass of SMGs, with large PAH/FIR ratio
and large stellar mass
2
Millimeter detection of Spitzer selected
hyperluminous infrared starburst galaxies

• OUTLINE
• Identification of luminous SMGs in SWIRE Spitzer
  survey
• General goals and background High z
  submillimeter galaxies (SMGs)
• Detection of SMGs in SWIRE and characterization
  of z2 SMG candidates
• 1.2mm Mambo observations of 24µm bright
  starburst SWIRE ULIRGs/HLIRGs
• Properties of 24µm bright SWIRE starbursts
• ? a subclass of SMGs rich in PAH and stars
• Search for AGN SWIRE HLIGRs
• Prospects

Main collaborators Carol Lonsdale, Mari Polletta
D. Farrah, D. Shupe, R. Zylka, S. Berta, B.
Siana, N. Fiolet, N. Bavouzet, G. Lagache, H. E.
Smith, F. Bertoldi., P. Cox, C. De Breuck, H.
Dole, D. Lutz, L. Tacconi, I. Perez-Fournon, H.
Aussel, H. McCracken, D. Clements, M.
Rowan-Robinson A. Franceschini, D. Frayer
3
SMGs strongest starbursts in the
Universe Important players of star formation at z
gt 2

• Giant starbursts at the peak of elliptical
  formation z 2-3 ? 1-4
• At least ULIRGs 1012Lo ? 1 per arcmin2
• Most exceptional HLIRGs 1013Lo ? 1 per 50-100
  arcmin2
• nothing equivalent in the local
  Universe
• probably in most massive DM halos
  
• ?progenitors of BCG/cD galaxies of
  clusters
• Only 500 SMGs provided by SCUBA/MAMBO surveys(
  lt 0.5-1 deg2)
• Importance of larger samples of high-z SMGs
• to traceSF in LSSs first massive dark
  matter halos
• and identify the rare most extraordinary
  objects (lensed, most luminous..)
• Waiting for SCUBA2, Herschel, AKARI surveys.
• Much larger (x20-40) samples already exist in
  Spitzer wide field surveys
• in particular SWIRE 50 deg2, 10000 -
  20000 SMGs

4

• z 7 20 ?
• Reionization
• PopIII stars 1st galaxies
• Formation of 1st galaxies
• Pop. II stars
• First AGN
• z 4 7
• Current frontier
• - Galaxy and Black-Hole early assembly
• - End of reionization
• z 1.5 - 4
• - Peak of star formation
• in early galaxies
• submm sources LBGs
• Peak of QSO activity

Main z ranges in the Cosmic History of galaxies
z Dphot (Gpc) 1000 ------------------
-- 20 230 12 130 --------------
------ z 6 60 -------------------- z2
16 ------------------- 0.5
3 -------------------- 0
300 million
3.5 billion
5
SMGs strongest starbursts in the
Universe Important players of star formation at z
gt 2

• Giant starbursts at the peak of elliptical
  formation z 2-3 ? 1-4
• At least ULIRGs 1012Lo ? 1 per arcmin2
• Most exceptional HLIRGs 1013Lo ? 1 per 50-100
  arcmin2
• nothing equivalent in the local
  Universe
• probably in most massive DM halos
  
• ?progenitors of BCG/cD galaxies of
  clusters
• Only 500 SMGs provided by SCUBA/MAMBO surveys(
  lt 0.5-1 deg2)
• Importance of larger samples of high-z SMGs
• to traceSF in LSSs first massive dark
  matter halos
• and identify the rare most extraordinary
  objects (lensed, most luminous..)
• Waiting for SCUBA2, Herschel, AKARI surveys.
• Much larger (x20-40) samples already exist in
  Spitzer wide field surveys
• in particular SWIRE 50 deg2, 10000 -
  20000 SMGs

6
Dust detection The Magic of the high-z submm
window
FIR emission of cold dust (Td 35-50 K)
- steep submm spectrum - compensates for
distance - Sn practically independent of z
from z 0.5 to 10 Effect also known as
 negative K correction 
Redshift degeneracy
from Bertoldi, Voss, Walter
LFIR 4x1012 S250(mJy) Lsun
7
Dust detection the magic of the submm window

• SCUBA(-MAMBO) census of high-z ULIRGs
• Take advantage of steep submm spectrum
• Account for good part (most) of submm background
• z from IR spectroscopy at Keck for radio ones
  (50)
• ? History of star formation up to z3-4
• Small but uncertain number at z gt 4

SCUBA (MAMBO) submm counts
SCUBA(-radio) redshift distribution Chapman,
Blain, Smail, Ivison 2005
8
Submm counts from the SHADES survey Coppin et
al. 2006
9

• Importance of extensive studies of larger samples
  of high-z SMGs
• Major starbursts of massive (elliptical)
  galaxies initial collapse or major mergers
• Parallel growth of super-massive black holes and
  feedback on the galaxy and the AGN
• Trace density peaks, first massive dark matter
  halos and
• early Large Scale Structures

• Importance of larger samples of high-z SMGs
• Various statistical studies
• Trace their spatial distribution along early LSS
• Identify the rare most extraordinary,
  mm-brightest ones
• ? strong lensed cases
• or most luminous (far-IR) galaxies LFIR gt
  1013 Lo, HLIRGs

10
Present SMG samples are very
limited Only 400 sources provided by
SCUBA/MAMBO surveys( lt 0.5 deg2)
Waiting for very large samples/areas (gt2007) of
SCUBA2 (850µm), ASTRO-F/AKARI (50-200 µm) and
(gt2008) Herschel (100-500 µm) Much larger
(x20-50) samples already exist (buried) in
Spitzer wide field surveys in particular SWIRE
50 deg2, 10000 - 15 000 SMGs
11
High-z millimeter studies at IRAM. 3.

• Millimeter detection of Spitzer selected
• hyperluminous infrared starburst galaxies
• The SWIRE survey
• Identification strategy of SMGs in SWIRE
• 1.2mm Mambo observations of SWIRE SMG
  candidates
• Properties of SWIRE 24µm bright starbursts ? a
  subclass of SMGs
• rich in PAHs (or AGN) and stars
• Multi-l data mid-IR spectro, 350µm, radio,
  optical
• Clustering
• Prospects

Main collaborators Carol Lonsdale, Mari Polletta
D. Farrah, D. Shupe, R. Zylka, S. Berta, B.
Siana, N. Bavouzet, G. Lagache, H. E. Smith, F.
Bertoldi., P. Cox, C. De Breuck, H. Dole, D.
Lutz, L. Tacconi, I. Perez-Fournon, H. Aussel, H.
McCracken, D. Clements, M. Rowan-Robinson A.
Franceschini, D. Frayer Nicolas Fiolet (stage
DEA)
12

• Spitzer provides the first wide field (mid-)IR
  surveys
• Spitzer is
• Very well matched to the detection of red
  galaxies (ellipticals, LIRGs) up to z1
• As well as AGN (Type 1 and 2 QSOs, etc.) up to
  z3
• Even pretty sensitive for high-z SMGs although
  most energy is in FIR outside
• of Spitzer sensitive l range

Wide-field Spitzer surveys (FLS, GTO, SWIRE)
cover in total about 70 deg2 SWIRE Legacy
Project 50 deg2 (PI Carol Lonsdale) µm 3.5 4
.5 5.8 8.0 24 µJy 3.7 4.5 48 38 106 nominal
limits Lonsdale et al. 2004 10 10 45 50 250
present catalogs (? ? 100 mJy at 160 µm, 20
mJy at 70 µm)
13

• Identification of SMGs in SWIRE
• Direct Spitzer detections of at least 90 known
  SCUBA/MAMBO SMGs at z2
• with SWIRE sensitivities, HLIRGs with S(850µm) gt
  7 mJy or S(1.2mm) gt 2.5 mJy
• are detected at gt90 at 3.8 and 4.5 µm
• and at 45 in most IRAC (3-8µm) bands and MIPS
  24µm

• 150-300 per deg² (0.05-0.1 per arcmin2)
• 0.7-1.5 104 in total SWIRE
• 20-40 times more than all existing
• MAMBO-SCUBA surveys

HLIRGs
14
Strategy for Identification of SMGs in SWIRE

• Careful identification criteria of HLIRG
  candidates from SWIRE optical data SMG SED
  templates
• Difficult extrapolation from 24µm to 1.2mm (need
  to simultaneously determine the SED and redshift
  from five SWIRE bands (3.6-24µm)

15
Spectral Energy Distribution (SED) of ULIRGs/SMGs
Starbursts
AGN AGNstarburst
16
detected with SCUBA or MAMBO
Spitzer infrared SED of
SWIRE
SCUBA-MAMBO
M. Polletta
17
detected with SCUBA or MAMBO
Spitzer infrared SED of
SWIRE
SCUBA-MAMBO
M. Polletta
18
Strategy for Identification of SMGs in SWIRE

• Careful identification criteria of HLIRG
  candidates from SWIRE optical data SMG SED
  templates (C. Lonsdale M. Polletta)
• Difficult extrapolation from 24µm to 1.2mm need
  to simultaneously determine the SED and redshift
  from five SWIRE bands (3.6-24µm)

• Four successive MAMBO projects scheduled at
  IRAM-30m (Fall 2005 - Winter 2007)
• for detecting SWIRE HLIRGs candidates at 1.2mm
  (S1.2mm gt2-5 mJy)
• 2005-2006 24µm-bright starbursts,
• best candidates 20/60 detections
• November 2006 AGN best candidates
• Winter 2007 24µm-bright starbursts,
• unbiased sample 16/32 detections

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1.2mm observations of 24µm-bright starburst SWIRE
HLIRGS Lonsdale, Omont, Polletta et al. to be
submitted to ApJ
Observation of a sample of 60 best candidates
with - pure starburst SED - S(24µm) gt
500 µJy - maximum in 5.8 µm IRAC band
(redshifted 1.6µm stellar bump ? z
2)  5.8µm-peakers  One third are detected
with S(1.2mm) gt 2 mJy Average value lt
S(1.2mm) gt 1.5 mJy Majority of the sources
are HLIRGs with LFIR close to 1013 Lo However,
very few sources above 5 mJy at 1.2mm (most
luminous SMGs) Follow-up at 350µm at CSO/SHARC2
? Tdust , accurate LFIR
20
(2005-2006 24µm-bright starbursts, best
candidates 20 detections November 2006 AGN best
candidates) - Winter 2007 24µm-bright
starbursts, unbiased complete sample in a
deep Lockman field (0.5 deg-2) with excellent
radio and X-ray data Goal to characterize this
subclass of strong starbursts with 5.8µm bump and
S(24µm) gt 400µJy (60 per sq. deg.) and its
average star formation rate. Previous samples
were biased towards the identification of the
most luminous objects, so that the average
starburst properties of the bulk of this class
remain undetermined. 50 detections 1.5-4
mJy. Average flux 1.5 mJy
21
(2005-2006 24µm-bright starbursts, best
candidates 20 detections November 2006 AGN best
candidates) - Winter 2007 24µm-bright
starbursts, unbiased complete sample in a
deep Lockman field (0.5 deg-2) with excellent
radio and X-ray data 32 sources, 20 with deep
radio data (Owen et al.) 50 detections 1.5-4
mJy. Average flux 1.5 mJy
22

• (2005-2006 24µm-bright starbursts, best
  candidates 20 detections
• November 2006 AGN best candidates)
• - Winter 2007 24µm-bright starbursts, unbiased
  complete sample
• in a deep Lockman field (0.5 deg-2) with
  excellent radio and X-ray data
• Goal to characterize this subclass of strong
  starbursts with 5.8µm bump and
• S(24µm) gt 400µJy (60 per sq. deg.) and its
  average star formation rate.
• Previous samples were biased towards the
  identification of the most luminous
• objects, so that the average starburst properties
  of the bulk of this class remain
• undetermined.
• 50 detections 1.5-4 mJy. Average flux 1.5 mJy
• Conclusions
• - Practically all 2000-3000 similar SWIRE
  sources - S(24µm) gt 400µJy,
• peaking at 5.8µm are starburst ULIRG SMGs, with
  strong PAH emission

23
High-z millimeter studies at IRAM. 3.

• Properties of SWIRE 24µm bright starbursts
• a subclass of SMGs rich in PAHs (or AGN)
  and stars
• IRAC data z2, large stellar mass and
  starburst dominated
• Large ratio 24µm/1.2mm Strong PAHs (
  Compton-thick AGN?)
• Mid-IR IRS Spitzer spectroscopy PAHs ( weak
  AGN?)
• 350µm CSO Tdust, LFIR and SFR
• Radio starburst/AGN, extension

24
Properties of z2 24µm-bright starburst SWIRE
HLIRGS 1. 5.8µm stellar peak Maximum in IRAC
band 3 Not AGN dominated ? starburst Redshif
ts in the range 1.7 2.5 ( a few z-spectro
1.7 1.9 ) Large stellar mass Berta et al.
2007 6x1010-6x1011 Mo, but depends
on age of AGB red giants 109yr
25
Properties of 24µm-bright starburst SWIRE
HLIRGS 2. Large ratio PAH/FIR emission
Ratio S(1.2mm)/S(24µm) much smaller than most
SMGs whose typical SED is relatively cold,
similar to Arp 220 SED rather similar to M82 or
NGC6090 or composite AGN IRAS 19254
 Optimized  sample 350µm detections
Unbiased sample x Literature sources
26
Properties of 24µm-bright SWIRE starburst

• 3. Mid-IR spectra obtained with Spitzer IRS 5
  sources detected at 1.2mm
• practically pure PAH spectra
• confirmation of redshift 2 (1.7 1.9)
• Weedman, Polletta
• et al. 2006

Observed spectrum
27
Properties of 24µm-bright SWIRE starbursts

• Mid-IR spectra obtained with Spitzer IRS
  practically pure PAH spectra

Average spectrum 9 starburst sources Weedman
et al. 2006
28
Properties of 24µm-bright starburst SWIRE
HLIRGS 4. 350µm CSO/SHARC2 detections CSO
Caltech 10m submm Mauna Kea SHARC2 new
generation TES submm camera Jan07 5 nights
lost April07 2/3 good nights (Kovacs et al. in
prep.) 8 SWIRE-MAMBO sources All
detected 350µm/1.2mm 7-20 Tdust25-45K (if
z2) LFIR2-20 1012 Lo SFRa few 102-a few
103Mo/yr
29
Properties of 24µm-bright SWIRE starbursts 5.
Radio properties - Winter 2007 24µm-bright
starbursts, unbiased complete sample in a
deep Lockman field (0.5 deg-2) with excellent
radio and X-ray data 50 detections 1.5-4 mJy.
Average flux 1.5 mJy Practically all our
24µm sources have a radio 30µJy detection Ratio
1.2mm/20cm in usual limits except a few non 1.2mm
detections and a strong radio source ? AGNs? A
number of extended radio sources gt 10kpc AGN or
extended starbursts? Winds??
30
Properties of 24µm-bright SWIRE
starbursts 6. Optical properties - Winter
2007 24µm-bright starbursts, unbiased complete
sample in a deep Lockman field (0.5
deg-2) with excellent radio and X-ray
data Moderately deep optical data R
24.5 1/3 of the sample R detected Need for
redshifts, optical (and near-IR) imaging similar
e.g. to Swinbank et al. for SCUBA sources A few
redshifts measured at Keck for similar sources by
Berta et al. 2007 most are weak AGN
31
Extended PAH emission in the super wind of
M82 Engelbracht et al. 2006
32
Properties of 24µm-bright starburst SWIRE
HLIRGS 2. Large ratio PAH/FIR emission

• Ratio S(1.2mm)/S(24µm) much smaller than most
  SMGs whose typical SED
• is relatively cold, similar to Arp 220
• Their SED is rather similar to M 82 or NGC 6090
  (or AGN composite IRAS 19254)
• Strong ratio of PAH/FIR emission
• ? ?
• Maybe they are more extended starbursts
• less opacity and less absorption of
• PAH emission
• With perhaps strong superwind as in
• M82 ?
• But scaled by a factor gt 10
• enrichment of intergalactic
• medium in heavy elements??

33
Properties of 24µm-bright starburst SWIRE
HLIRGS 2. Large stellar masses
Masses in red stars might range from 6x1010 to
6x1011 Mo, if the mean stellar age is below 109
years (Berta et al. 2007) ? They are probably
young massive ellipticals in the final stages of
star formation, when a good part of their
stellar mass is already in place, yet very high
rates of star formation are still proceeding.
The rare starburst episode is likely to be
short lived, to avoid that the total accumulated
stellar mass by the end of the burst exceeds that
observed in the largest local ellipticals. ?
Probably one of the latest gas-rich major mergers
of a massive elliptical
34
Properties of 24µm-bright SWIREstarbursts 7.
Clustering The 5.8µm-peaking, 400µJy 24µm SWIRE
sources (density 60 deg-2) are very highly
clustered, with comoving clustering length r0
15-20 Mpc from Farrah etal. 2006 (see also
Magliocchetti et al. 2007 for similar sources
Spitzer FLS with f24 gt 350µJy and Rlt25.5,
density 350 deg-2) They should trace most
massive, rare dark matter halos with MDM a few
1013Mo at z 2 But redshifts are mandatory to
actually identify such DM halos
35

• MAMBO observations of SWIRE HLIRG AGN candidates
• October-November 2006 bad weather 1/3 of
  proposal observed
• XMM-LSS and Lockman SWIRE fields
• 14 Sources fitted with composite starburst-AGN
  SEDs
• - average flux 1.53 /-0.40 mJy
• - the majority should be close to HLIRGs
• 11 sources with  Torus  featureless SEDs
• - average flux 0.46 /-0.38 mJy
• - few HLIRGs

36

• MAMBO observations of SWIRE HLIRG AGN candidates
• October-November 2006 bad weather 1/3 of
  proposal observed
• XMM-LSS and Lockman SWIRE fields
• 14 Sources fitted with composite starburst-AGN
  SEDs
• - average flux 1.53 /-0.40 mJy
• - the majority should be HLIRGs
• 11 sources with  Torus  featureless SEDs
• - average flux 0.46 /-0.38 mJy
• - few HLIRGs
• Confirmed detection of two exceptional sources
• - u-dropouts (J. Bergeron) in D1 CFHTLS Deep
  Field ? z 3 4
• - probably red QSOs
• - S24µm 23 mJy

37

• MAMBO observations of SWIRE HLIRG AGN candidates
• Confirmed detection of two exceptional sources
• - u-dropouts in D1 CFHTLS Deep Field ? z 3 4
• - probably red QSOs
• - S24µm 23 mJy
• - S1.2mm 5 mJy !
• - Nature of IR emission still unknown
• Redshift confirmed 3.86 and spectrum obtained for
  one of them
• by Chelliah, Petitjean et al. with 2dF
• Very strong metal lines

38

• Other projects in progress
• with CFHTLS Spitzer data and IRAM observations
• Identification of Type 1 and 2 QSOs in
  CFHTLS/Spitzer fields
• Pei Yu, J. Bergeron, X. Liu N. Bavouzet C.
  Willott and Brown Dwarf Team
• 1.2mm MAMBO maps of deep Spitzer multi-l
  fields
• A. Baker, C. Lonsdale, F. Owen F. Bertoldi .
• 1.2mm observations of high z QSOs and IRS
  Spitzer sources
• M. Jarvis C. Willott Ran Wang D. Lutz, L. Yan
  .
• CO observations of high z sources
• I. Smail, P. Cox D. Lutz, L. Yan Ran Wang F.
  Bertoldi R. Genzel, L. Tacconi,
• R. Maiolino, S. Chapman .

39

• PROSPECTS
• New 1.2mm Mambo observations on weaker 24µm
  sources in Fall 2007
• Continue follow-up at 350µm at CSO ? Tdust ,
  accurate LFIR
• ?
• IRS/Spitzer application for detailed PAH studies
• Improve redshift determination, ? spectroscopy,
  in particular for proto-cluster
• identification
• CO search with IRAM interferometer when accurate
  redshifts
• Morphology studies visible near-IR
• ?
• Full identification of SWIRE z2 HLIRGs (
  ULIRGs) warranted with Scuba 2

40
CO detection in 18 high-z QSOs
Plateau de Bure IRAM interferometer
41
(No Transcript)
42
(2005-2006 24µm-bright starbursts, best
candidates 20 detections November 2006 AGN
best candidates) - Winter 2007 24µm-bright
starbursts, unbiased sample 10 tentative
detections 2-4 mJy
43
Confirmed detection of three exceptional sources
- u-dropouts in D1 CFHTLS Deep Field ? z 3
4 (to be confirmed) - probably red QSOs - S24µm
13 mJy - S1.2mm 5 mJy - Nature of IR
emission still unknown - Very large ratios
24/8.0µm and 8.0/5.8µm
Band u g r i z
3.6 4.5 5.8 8.0 24um 1.2mm
20cm ---------------------------------------------
--------------------------------------------------
------------------------- SW49208 z 3
3.5 m_AB lt26 24.6 23.4 23.0 22.5
20.9 20.7 Flux(µJy)
3.6 15.8 19.7 lt50 185
2406 5000 350 -----------------------------
--------------------------------------------------
----------------------------------------- SW55275
z 3.5 - 4 m_AB 25.5 23.0 21.7
22.0 22.4 20.9 20.5 Flux(µJy)
4.0 15.5 23.0 lt50 245 3271
5000 140 ----------------------------------
--------------------------------------------------
44
Confirmed detection of two exceptional sources
- u-dropouts in D1 CFHTLS Deep Field ? z 3
4 (to be confirmed) - probably red QSOs - S24µm
23 mJy - S1.2mm 5 mJy - Nature of IR
emission still unknown - Very large ratios
24/8.0µm and 8.0/5.8µm
Band u g r i z
3.6 4.5 5.8 8.0 24um 1.2mm
20cm ---------------------------------------------
--------------------------------------------------
------------------------- SW49208 z 3
3.5 m_AB gt26 24.6 23.4 23.0 22.5
20.9 20.7 Flux(µJy)
3.6 15.8 19.7 lt50 185
2406 5000 350 -----------------------------
--------------------------------------------------
----------------------------------------- SW55275
z 3.5 - 4 m_AB 25.5 23.0 21.7
22.0 22.4 20.9 20.5 Flux(µJy)
4.0 15.5 23.0 lt50 245 3271
5000 140 ----------------------------------
--------------------------------------------------
SW192934 z 3 3.5 m_AB gt26 24.3 23.7
23.9 x Flux(µJy) 1.0 x
14.0 18.9 lt50 97 1050 4000?
x -----------------------------------------------
--------------------------------------------------
-----------------------