ALMA and VLA imaging of intense galaxy-wide star formation at z~2: - - PowerPoint PPT Presentation

Wiphu Rujopakarn


Chulalongkorn University


 Durham — August 1, 2017

ALMA and VLA imaging of intense galaxy-wide star formation at z~2: bridging SMGs to the Main Sequence

Color composite: Hubble Space Telescope (visible wavelength)
 Red overlay: Karl G. Jansky Very Large Array (radio wavelength)

Distant Star-Forming Galaxies

in the Hubble Ultra-Deep Field

9.0 billion light-years 10.9 billion light-years 9.4 billion light-years 11.2 billion light-years

Team: Alexander, Biggs, Bhatnagar, Ballantyne, Cibinel, Dickinson, Dunlop, Elbaz, Geach, Hayward, Ivison, Jagannathan, Kirkpatrick, McLure, Michałowski, Miller, Narayanan, Nyland, Owen, Pannella, Papovich, Pope, Rau, Rieke, Robertson, Scott, Silverman, Swinbank, van der Werf, van Kampen, Weiner, Windhorst et al.

Key questions

• How/when did galactic spheroid and their SMBH form?
• What is the true morphology of star formation in main-

sequence galaxies at z ~ 2? Compact? Disk-wide?

• Where exactly is the accreting SMBH in relation to the

sites of star formation?

• Spatially-resolved imaging of the bulk of star formation

and pinpointing AGN in SFGs at z ~ 2 is key

3

Typical, main- sequence SFGs at z ~ 2


— mostly rotation- dominated, disk-like systems

KMOS3D

Wisnioski+15

All the actions occurred in the ‘dust era’— Almost no rest-UV light

escape from galaxies forming stars at just ≳0.2 the MS rate. The true faces of growing galaxies are mostly hidden

Dunlop, WR et al. 2017

1 2

M yr-1 kpc-2

52

Ellis, R. S. et al. 2013, ApJ, 763, L7 Fujimoto, S. et al. 2016, ApJS, 222, 1 Geach, J. E. et al. 2013, MNRAS, 432, 53 Hughes, D. H. et al. 1998, Nature, 394, 241 Kennicutt, R. C. & Evans, N. J. 2012, ARA&A, 50, 531 Kirkpatrick, A. et al. 2015, ApJ, 814, 9 Madau, P. & Dickinson, M. 2014, ARA&A, 52, 415 McLeod, D. J. et al. 2015, MNRAS, 450, 3032 McLure, R. J. et al. 2013, MNRAS, 432, 2696 Michalowski, M. J. et al. 2016, arXiv:1610.02409 Narayanan, D. et al. 2015, Nature, 525, 496 Noeske, K. G. et al. 2007, ApJ, 660, L43 Parsa, S. et al. 2016, MNRAS, 456, 3194 Rujopakarn, W. et al. 2016, arXiv:1607.07710 Speagle, J. S. et al. 2014, ApJS, 214, 15 Walter, F. et al. 2016, ApJ, in press, arXiv:1607.06768 Weiss, A. et al. 2009, ApJ, 707, 1201

far-infrared luminosity density as a func- tion of redshift, converting the luminosity densities to visible and obscured star formation rate densities respectively (see Kennicutt & Evans, 2012). Our knowledge of the evolution of the cosmic star formation rate density follow- ing the fjrst results from WFC3+HST and Herschel (both of which came into

• peration in 2009) was reviewed by

Behroozi et al. (2013) and Madau & Dick- inson (2014). However, the deeper census

• f dust-obscured star formation enabled

by the new ALMA results allows us to better determine the relative evolution

• f obscured and unobscured star forma-

tion at redshifts = 2–5. The implications

• f our new results are summarised in

Figure 5. The upper panel shows the evo- lution of unobscured, obscured and resulting total star formation rate density as a function of redshift, with the lower panel simply showing the equivalent information as a function of cosmic time. Now it can be seen clearly that, while the star formation density around the peak epoch at = 2–2.5 is overwhelm- ingly dominated by dust-obscured emis- sion from massive galaxies, at redshifts higher than ~ 4 the dust-obscured component drops off rapidly, with the consequence that the star-forming Uni- verse is primarily unobscured at earlier times (i.e., within 1.5 Gyr of the Big Bang). Deeper imaging (for example, Walter et al., 2016) and wider-area surveys with ALMA have the potential to clarify this behaviour still further, and in particular to determine the evolution of dust-obscured star formation activity as a function of redshift at fjxed galaxy stellar mass. In addition, the sources uncovered by these deep ALMA surveys are obvious attractive targets for further ALMA pointed imaging+ spectroscopy extending to shorter wave- lengths, and for future study with the James Webb Space Telescope (JWST).

Behroozi, P. S., Wechsler, R. H. & Conroy, C. 2013, ApJ, 770, 57 Bourne, N. et al. 2016, arXiv:1607.04283 Burgarella, D. et al. 2013, A&A, 554, 70 Chabrier, G. 2003, PASP, 115, 763 Coppin, K. E. K. et al. 2006, MNRAS, 372, 1621 Cucciati, O. et al. 2012, A&A, 539, 31 Daddi, E. et al. 2007, ApJ, 670, 156 Dunlop, J. S. et al. 2016, MNRAS, in press, arXiv:1606.00227

Astronomical Science

Figure 5. The evolution of co-moving star formation rate density (ρSFR) as a function of redshift (upper panel) and cosmic time (lower panel). The blue points and blue (double power-law) fjtted curve show the raw, unobscured UV-derived values of ρSFR (derived from: Cucciati et al., 2012; Parsa et al., 2016; McLure et al., 2013; and McLeod et al., 2015). The red points and curve indicate the dust-obscured estimates of ρSFR derived from the present ALMA study of the HUDF (Dunlop et al., 2016). The black points and curve show total ρSFR; at < 2 the data are from Cucciati et al. (2012) and Burgarella et al. (2013), while at > 2 the black data points are simply the sum of the blue (unobscured) and red (dust-

• bscured) values.
• Dunlop J. S., A Deep ALMA Image of the Hubble Ultra Deep Field

Redshift (z) Cosmic Star Formation Rate (M☉yr-1 Mpc-3)

200 400 600 800 200 400 600 800 Optical image:

Actual picture:

Hubble, 600 nm VLA, 5 cm

☉

A Typical Star-Forming Galaxy at z ~ 1.6

SF clumps in optical/UV not always indicate mergers; also, optical/UV clumps contains <20% of SF

Unobscured SF Obscured SF

Combining JVLA and ALMA

5

Sub-arcsecond resolution,
 extinction-free, sensitive tracers 


• f star formation at z ~ 2

ESO / NRAO

• Single pointing centered at the HUDF
• 6 GHz, 7’ field, 0.3’’ resolution
• A, B, C configs; 177 hours total
• 0.32 μJy/beam RMS
• 5σ SFR limit: 15 M⊙/yr/beam at z = 2
• Deepest radio image of the sky as of 2017

Courtesy D. Medlin 6

VLA HUDF Survey

1’’ ~ 8 kpc from 1 < z < 3; beam ~ 2.5 kpc

HUDF

ALMA HUDF — PI: Dunlop ALMA-JVLA — PI: Kohno GOODS-S ALMA — PI: Elbaz

ALMA ‘wedding cake’ surveys in HUDF and GOODS-S


— three nested ALMA dust continuum surveys to capture distant SFGs

68 sq. arcmin, 256 GHz, 128 uJy/beam rms 23 sq. arcmin, 271 GHz, 60 uJy/beam rms 4.5 sq. arcmin, 220 GHz, 29 uJy/beam rms

ALMA Deep Field published in Dunlop, WR+16; Elbaz Cy4 data delivered, Cy5 program approved;
 Kohno data delivered; Walter+ line scan covers the HUDF

GOODS-S


— central region of the 
 Chandra Deep Field South

Hubble ACS/WFC3, Spitzer, and Herschel deep survey footprint

ALMA 1.3 mm, 29 μJy/beam rms Jansky VLA 5 cm, 0.3 μJy/beam rms

HUDF

WR+16
 Dunlop, WR+17

16 sources in VLA, not in ALMA 11 sources in ALMA and VLA

Why both VLA and ALMA?

9

• 177h VLA is more sensitive to SF at

z < 2.6; ALMA 20h wins at z > 2.6 
 — need both to cover the peak of galaxy assembly (z ~ 1 - 3)

• VLA: SF + AGN


ALMA: dust associated to SF; generally AGN-free

• Map SFR, cold dust, and in some

cases, pinpoint radio AGN

2 4 6 z 1 10 100 1000 SFR Sensitivity

SFR limit (M⊙/yr/beam, 4𝝉) ALMA HUDF VLA

The sample of VLA and ALMA-selected SFGs are in the main sequence at z ~ 2

10

ALMA HUDF sample MS fit (z ~ 2)

Daddi+07
 Whitaker+12
 Whitaker+14
 Speagle+14

• 11 galaxies; 6 host X-ray AGN
• log(M*/M⊙) = 9.8 − 10.8
• SFR = 79 − 318 M⊙/yr
• fgas ~ 0.5 ± 0.2


tdep ~ 0.4 ± 0.2 Gyr

• Dust and gas properties 


consistent with MS SFGs

Dunlop, WR+17

Stellar-mass maps serves as a reference frame 
 to pinpoint sites of intense star formation

Pixel-by-pixel SED fitting (Cibinel et al. 2015) using 29.5 - 30.5 mag AB ACS/WFC3 images in the HUDF;
 Perform asymmetry-M20 analysis on these maps to classify as isolated or disturbed.

bzH H-band ΣStellar Mass 1’’

Rest-frame optical has
 SF clumps in addition 
 to the M* clump Spatially-resolved SED
 fitting is needed to map
 the M* distribution Merger or
 isolated? HST/F160W

z = 2.75

Cibinel+15

VLA ΣSFR

2.5 5.0 7.6 0.2 1.1 2.0

ALMA Σdust UDF8

HST 1.0, 1.4, 1.6 μm

Star formation and cold dust maps from VLA and ALMA

Bell 2003 indicator, assuming S ~ v-0.7 Li & Draine 2001 dust, Td = 25 K

Will IRX-beta works 
 for MS galaxies at z ~ 2?

z = 1.55, 4’’ x 4’’ cutouts

106Mkpc−2

Myr−1kpc−2

HST 0.6 μm

Rest-frame Optical Rest-frame UV

WR+16

Disk-wide star formation at z ~ 2

UDF6

z = 1.41

200 400 600 800 200 400 600 800 200 400 600 800 200 400 600 800

0.2 1.2 2.2 2.6 6.1 9.6

200 400 600 800

6.2 7.7 9.2

Isolated

UDF7

800 800 800 800 800

UDF8

z = 1.55

200 400 600 800 200 400 600 800 200 400 600 800 200 400 600 800

0.2 1.1 2.0 2.5 5.0 7.6

200 400 600 800

6.5 8.3 10.2

Isolated

5 kpc

UDF1

z = 3.00

200 400 600 800 200 400 600 800

0.6 µm

HST

200 400 600 800 200 400 600 800

JVLA ALMA

1.6 µm

HST

1 9 17

ΣSFR

VLA Myr−1kpc−2

2 16 31

Σdust

ALMA 106Mkpc−2

200 400 600 800

5.9 7.9 10.0

ΣM*

HST

Isolated

logMkpc−2

Bulge

WR+16

Galaxy-wide star formation at z ~ 2 in disturbed hosts

5 kpc

UDF4

z = 2.43

200 400 600 800 200 400 600 800

0.6 µm

HST

200 400 600 800 200 400 600 800

JVLA ALMA

1.6 µm

HST

0.6 3.2 5.7

ΣSFR

VLA Myr−1kpc−2

2 6 10

Σdust

ALMA 106Mkpc−2

200 400 600 800

5.8 7.5 9.2

ΣM*

HST

Disturbed

logMkpc−2

UDF2

z = 2.79

200 400 600 800 200 400 600 800 200 400 600 800 200 400 600 800

1 8 15 2 14 26

200 400 600 800

5.9 7.6 9.4

Disturbed

UDF3

z = 2.54

200 400 600 800 200 400 600 800 200 400 600 800 200 400 600 800

2 11 20 2 13 25

100 200 300 400 500 600

6.1 7.5 8.9

Disturbed?

WR+16

• Star formation and stellar mass

barycenters are < 1 kpc apart, effectively co-spatial — intense SF reside near stellar mass barycenter

• r(SF) ~ r(M*) — disk-wide SF
• Median r(SF) ~ 2 kpc in both SF

and AGN hosts

• Disk SFRSD ~ 1-20 M⊙/yr/kpc2

Galaxy-wide star formation at z ~ 2

1 2 3 4 5 6 Radius encircling half of stellar mass (kpc) 1 2 3 4 5 6 Star formation radius (kpc)

43 185 326

X-ray AGN SF

SFR (Myr−1)

WR+16

• Star formation and stellar

mass barycenters are < 1 kpc apart, effectively co-spatial — intense SF reside near stellar mass barycenter

• r(SF) ~ r(M*) — disk-wide SF
• Median r(SF) ~ 2 kpc in both

SF and AGN hosts

Galaxy-wide star formation at z ~ 2 vs. “red nuggets”

1 2 3 4 5 6 Radius encircling half of stellar mass (kpc) 1 2 3 4 5 6 Star formation radius (kpc)

43 185 326

X-ray AGN SF

SFR (Myr−1)

a b c d e f

a

re, F160W (rest−optical) [kpc] re, 870µm (FIR) [kpc]

0.5 1 1.5 2 2.5 3 0.5 1 1.5 2 2.5 3

Progenitors of compact quiescent galaxies at z ~2 Barro, WR+16 WR+16

Size measurements from stacked ALMA samples 
 agreed with individual HUDF detections:

Lindroos+16; ALMA LABOCA ECDFS Sub-mm Survey

K20 — 0.73’’ +- 0.14’’

52 sources with (z − K − 0.04) > 0.3(B − z + 0.56) − 0.5 which separate the galaxies from the stars

sBzK — 0.73’’ +- 0.15’’


22 actively star-forming galaxies selected using the sBzK criteria, i.e., (z − K − 0.04) − (B − z + 0.56) > −0.2

DRG — 0.65’’ +- 0.17’’


22 Distant Red Galaxies selected using J − K > 1.32
 


ERO — 0.71’’ +- 0.14’’

25 Extremely Red Objects selected using (R − K) > 3.35 and (J − K) > 0.1

Typical sizes: ~0.7’’, corresponding to 5 kpc at z = 2

• Main-sequence SFGs are 2x

larger in star-formation diameters than SMGs

• A more compact SFG

populations emerges at SFR 
 > 300 M⊙/yr at z ~ 2

• The dotted line is L6.2/LIR, 


a size proxy — not a fit!

WR+16

100 1000 1 10 Deconvolved Diameter (kpc)

Simpson et al. (2015) Hodge et al. (2016) Biggs & Ivison (2008) Rujopakarn et al. (2016)

SFR (Myr−1)

z ∼ 2

log(L6.2µm/LIR), Shipley et al. (2016)

ALMA size measurements for higher star formation rate samples — Increasing compactness at higher SFRs

Bridging the Main Sequence to SMGs — an open question

UDF5

z = 1.76

0.2 1.2 2.2

UDF6

z = 1.41

0.2 1.1 2.0

UDF8

z = 1.55

0.3 1.4 2.5

ΣSFR

VLA Myr−1kpc−2

=

• ´
• =
• 2

=

• ´

;

3

• 2

=

• =
• ~
• ~

s ~ = ~

• 100

1000 1 10 Deconvolved Diameter (kpc)

Simpson et al. (2015) Hodge et al. (2016) Biggs & Ivison (2008) Rujopakarn et al. (2016)

SFR (Myr−1)

z ∼ 2

log(L6.2µm/LIR), Shipley et al. (2016)

• 500

500

• 1

1 2 3 4

• 500

500

• 1

1 2 3 4

Radio Velocity (km s-1) CO(5-4) flux (mJy beam-1) PACS787-E PACS787-W N E 3 kpc Background: dust continuum

Main Sequence

SMGs Extreme starbursts

~100 M⊙/yr
 log(M*/M⊙) ~ 10.5 Disk-wide SF WR+16 ~400 M⊙/yr Disk-like
 Hodge+16


 Need JWST for 
 M* distribution

A ~1500 M⊙/yr starbursts resolved by ALMA into two counterrotating nuclei

Silverman, WR+, in prep.

2.5 5.0

Are ‘disk-wide’ really disk-wide or giant clumps get smoothed into a disk? — needs ALMA and JWST

?

UDF8 at z = 1.55
 WR+16 Jansky VLA C-band continuum map of M82; Marvil, Owen, Eilek 13 GMCs at z ~ 2 are 100x larger (e.g., Swinbank+12)

ALMA Cycle 5 program approved


0.07’’ resolution, 1.2 M⊙/yr/beam rms at z ~ 2.7

5’’

z = 3.0 z = 2.9 z = 2.7

VLA/14A-360 Hubble Chandra

4 - 8 GHz, 71h integration 1.25, 1.40, 1.60 μm 0.5 - 8 keV, 4 Ms integration

Challenges in pinpointing the sites of SMBH accretion


X-ray is ~1’’ resolution; optical indicators are limited to ~0.1’’ of IFUs and may be obscured — Radio is the only way to localize AGN to sub-kpc at z ~ 2

X-ray 
 AGN SFG Radio 
 AGN Chandra PSF is 0.7 - 3.6’’ at off axis angles of 1’ - 9’; VLA C-band/A-array is 0.3’’

326 Msun/yr 247 Msun/yr 56 Msun/yr

177h integration

Far-Infrared/Radio correlation holds for SFGs at z ~ 2

1.0 1.5 2.0 2.5 3.0 3.5 Redshift

• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log(S5 cm/S1.3 mm)

X-ray AGN SF 2× SF

42.5 43.0 43.5 44.0 10 11 12 13

logLX

AGN(0.5-8.0 keV)

logLIR

SED

• Far-IR/radio correlation holds at z ~ 2

for individual main-sequence SFGs

• For SFGs, the scatter around the

predicted values is small — small range of Tdust

• For AGN, radio is enhanced, with the

X-ray faint being more elevated

• X-ray/radio AGN dichotomy at z ~ 2?

— unlikely, but still need larger sample

WR+16

Radio emission well over the level implied by the far- IR/radio correlation pinpoints the AGN

200 400 600 800

HST

5 kpc

i814J125H160

200 400 600 800

0.6 µm

HST

200 400 600 800

Σdust

ALMA

1.0 5.4 9.7

106Mkpc−2

7.2 8.5 9.9

200 400 600 800

ΣM*

HST

logMkpc−2

AGN VLA

1.0 1.5 2.0 2.5 3.0 3.5 Redshift

• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log(S5 cm/S1.3 mm)

X-ray AGN SF 2× SF

42.5 43.0 43.5 44.0 10 11 12 13

logLX

AGN(0.5-8.0 keV)

logLIR

SED

UDF7

AGN can be located down to θbeam/(2 × SNR), better than 5 mas in this case

WR+16

Expanding the sample of radio-dominated AGN with ALMA observations by scraping the ALMA archive

HUDF

Band-6 Deep Field

COSMOS

Band-7 Compilation

COSMOS

Band-6 Compilation

1 2 3 4 z

• 3
• 2
• 1

1 2 log(S3 GHz/S240 GHz)

COS5 COS4 COS3

ngalaxy = 117

1 2 3 4 z

• 3
• 2
• 1

1 2 log(S3 GHz/S343 GHz)

COS1 COS6 COS2

ngalaxy = 187

1 2 3 4 z

• 3
• 2
• 1

1 2 log(S6 GHz/S221 GHz)

UDF7

ngalaxy = 11

WR+16, WR+17 in prep.

VLA pinpoints AGN location; ALMA traces ‘pure’ SF

WR+16, WR+17 in prep.

10-1 100 101 102 103 104 105 Rest-Frame Wavelength (µm) 10-8 10-6 10-4 10-2 Fν (Jy)

COS1

z = 2.87

AGN

NOR WDD HDD

SF

CE01 DH02 R09

10-1 100 101 102 103 104 105 Rest-Frame Wavelength (µm) 10-8 10-6 10-4 10-2 Fν (Jy)

COS4

z = 3.25

AGN

NOR WDD HDD

SF

CE01 DH02 R09

10-1 100 101 102 103 104 105 Rest-Frame Wavelength (µm) 10-8 10-6 10-4 10-2 Fν (Jy)

COS2

z = 2.92

AGN

NOR WDD HDD

SF

CE01 DH02 R09

ALMA

VLA

Location of AGN in relation to the sites of intense SF

WR+16, WR+17 in prep.

10 kpc

UDF7

z = 2.59

VLA

ALMA

F125W

F160W

Ks

1 kpc

Central 1′′

COS1

z = 2.87

VLA

ALMA

J

H

Ks

COS2

z = 2.92

VLA

ALMA

J

H

Ks

Positional uncertainties:

Absolute astrometry of VLA and ALMA are better than 30 mas, 250 pc at z ~ 2.5

ALMA

VLA

Presence of existing stellar bulge is unclear from deep NIR imaging

Cospatiality of SMBH accretion and intense SF at z ~ 2.5

WR+16, WR+17 in prep.

500 pc

UDF7

z = 2.59

σpos(SF) = 159 × 125 pc σpos(AGN) = 31 × 52 pc

500 pc

COS1

z = 2.87

σpos(SF) = 90 × 89 pc σpos(AGN) = 9 × 9 pc

500 pc

COS2

z = 2.92

σpos(SF) = 32 × 33 pc σpos(AGN) = 20 × 20 pc

SF size

SF centroid uncertainties

AGN centroid uncertainty is smaller than the star symbol

Implications are still being explored, but we now know with certainty that AGN occurs within the central region of intense SF — consistent with a picture of in-situ bulge/SMBH coevolution

Summary

• Intense star formation in main-sequence SFGs is galaxy-wide
• Barycenters of ΣSFR, ΣM*, Σdust distributions are co-spatial; 


newly formed stars will be at the center — in situ bulge formation

• A more compact SFG population appears to emerge at 


SFR > 300 M⊙/yr (i.e., above the main-sequence at z ~ 2)

• Radio excess over ALMA SF level is capable of pinpointing the

location of AGNs in distant galaxies down to milliarcseconds

• Star formation and SMBH accretion are cospatial — evidence for

in situ bulge-SMBH coevolution

28