1. Probing the Faint Radio Population
First Results from the VLA-COSMOS Survey
Eva Schinnerer (MPIA)
V. Smolcic, C.L. Carilli, M. Bondi, P. Ciliegi,
K. Jahnke, N.Z. Scoville
VLA-COSMOS Team
COSMOS Collaboration

2. Radio continuum - Components
synchrotron
free-free
Thermal
dust
M82
z=9
z=0
Condon (1992)

3. The VLA-COSMOS Survey(s) NRAO Very Large Array
VLA-COSMOS team: Schinnerer (PI)
Smolcic, Carilli, Bondi,
Ciliegi, Scoville, Bertoldi,
Blain, Impey, Jahnke,
Koekemoer, Le Fevre, Urry,
Vettolani
COSMOS 1.4 GHz (20cm) continuum (1.5” resolution)
Pilot project (10hr): A array (Schinnerer et al. 2004)
~ 250 sources
~ 1 sqrdeg; rms ~ 30 Jy/beam
Large project (275hr): A+C array (product release: ~ June’06)
~ 3,600 sources
~ 2(1) sqrdeg; mean rms ~ 15(10) Jy/beam;
Deep project (60hr): A array (data reduction underway)
~ 1 sqrdeg; expected rms ~ 6.8 Jy/beam (central 30’)

4. VLA-COSMOS
1.4 degree

5. 20cm continuum surveys: VLA-COSMOS survey: unique phase space
X-ray - mm complementary data
~ 80% optical counterparts --> IRAC: 100%(?)
spectroscopy (> 250 available; expected: 50%)
(zCOSMOS, IMACS/Magellan)

6. Radio Surveys - Limits 14 AGN - SF 13 Log (FIR Luminosity) 12 ULIRGs
Sadler et al. (2002), Chapman et al. (2003)
Radio Surveys - Limits 9 10 11 12 13 14
Log (FIR Luminosity)
ULIRGs
LIRGs
AGN - SF
Milky Way

7. Star Formation
AGN
10kpc
Local
example
10kpc
COSMOS
examples

8. First Results - Wide Angle Tail Radio Galaxy
(Smolcic et al. 2006)
z ~ 0.2
20cm
Xray: rainbow
Optical: RGB
Radio: red
CWAT-01 at z~0.2:
Reveals complex galaxy cluster assembly
Evidence for mass build-up (~ 20% Coma cluster)

9. Faint Radio Sources - Number Counts
AGN
steep
flat
starbursts
spirals
SKA EVLA HDF/COSMOS++ 1st/NVSS Cambridge
Hopkins et al. (2000)

10. First Results - (preliminary) Source Counts
(Bondi et al., in prep.)
(uncorrected)

11. First Results - Optical Counterparts
(Ciliegi et al., in prep.)
~ 3600 sources (4.5sigma)
R < 1.5”: radio – optical associations (87.5 %)
for I < 23.5: 1570
R < 1.0”: 2886 radio-optical associations (79.1%)
for I < 23.5: 1526

12. First Results - Population Mix
Using SED type:
Early
Late
Starburst
but be aware of type 1 AGN
Using Morphology:
ACS point-sources --> AGN
All 20cm radio sources
see Poster by Smolcic

13. First Results - Identification of (Sub)mm Galaxies
(Bertoldi et al. 2006)
23 MAMBO sources (3.5<  < 7)
50% radio counterparts > 30 Jy
20’

14. First Results - Radio Properties of LAEs
(Carilli et al. 2006)
58 Ly emitters (z~5.7):
(Ajiki et al. 2006)
No radio counterparts < 30 Jy
No AGN (FRI ~ M87)
no (sub)mm galaxy w/
SFR > 1000 Msun
Stacked limit (2):
4.4 Jy (all LAEs)
5.0 Jy (UV-detected LAEs)
mean SFR < 250 Msun
consistent w/ known
properties of LAEs
20”

15. VLA-COSMOS -
- Status
- 3,644 sources (> 4.5) in 2 sqrdeg (rms ~ 10 Jy)
- central 30’ down to rms ~ 7 Jy (underway)
- ~ 80% optical counterparts (--> spectroscopy)
- Science
- 20cm emission: SF/AGN contribution
- single targets: e.g. WAT radio galaxy
- identification: (sub)mm sources
- stacking analysis: LAE, …
- Products
- 1.4 GHz image
- source catalog
- public IRSA archive: ~ June ‘06

17. First Results - (preliminary) Source Counts
(Bondi et al., in prep.)

18. Star Formation
COSMOS examples
Local example
6 cm
Schinnerer et al.

19. VLA-COSMOS
1.4 degree

20. VLA-COSMOS vs. HST morphologies2”
z ~ 0.2
z ~ 0.2 2” 2”
z ~ 1.0 2”
z ~ 1.3

21. The VLA-COSMOS Survey NRAO Very Large Array VLA Large Project
PI: Schinnerer
Smolcic, Carilli, Bondi,
Ciliegi, Scoville, Bertoldi,
Blain, Impey, Jahnke,
Koekemoer, Le Fevre, Urry,
Vettolani
A+C configuration @ 1.4 GHz (20cm) continuum
270hr: ~ 3,500 sources (catalog underway)
~ 2 sqrdeg; rms ~ 10 microJy/beam;
~ 1.5” resolution (weighting: robust =0)
~ 45 days total
+ 60hr: A array (awarded: spring 2006)
central 30’: rms --> 6.8 microJy/beam

22. VLA-COSMOS - Source Numbers
~ 3500 sources (4.5sigma)
~ 80% optical IDs => ~ 2300

23. Within 1. 5 arcsec we have 3181 (1570 I<23
Within 1.5 arcsec we have 3181 (1570 I<23.5) radio – optical associations (87.5 %)
Within 1.0 arcsec we have 2886 (1526 I<23.5) association (79.1 %)

28. AGN - Radio Galaxies (+ …)
COSMOS
examples
COSMOS
examples
AGN - Radio Galaxies (+ …)
10kpc
Local example - Cygnus A