1. The e-MERGE Legacy Survey – an e-MERLIN+JVLA Ultra-Deep Survey Tom Muxlow JBCA Manchester Ian Smail, Ian McHardy & the e-MERGE Consortium EVN Symposium - Cagliari 7 th October 2014, High-resolution mapping of the µJy radio source population

2. How does the star- formation density vary with cosmic epoch ? What are the best extinction-free measures of star-formation rate at high redshift ? Radio continuum luminosity correlates with far-infrared emission, - both of which trace star formation in galaxies. Star-formation at High Redshift Radio is an excellent tracer of (obscured) star-formation Extinction-free !! – but need to remove AGN contamination – but need to remove AGN contamination – requires spectral information & high angular resolution – requires spectral information & high angular resolution – can also study AGN - star-formation feedback Radio is an excellent tracer of (obscured) star-formation Extinction-free !! – but need to remove AGN contamination – but need to remove AGN contamination – requires spectral information & high angular resolution – requires spectral information & high angular resolution – can also study AGN - star-formation feedback Multiple tracers of star-formation rate available – but many are subject to extinction at high z Total amount of star-formation missed from UV surveys at such high redshifts remains uncertain… Multiple tracers of star-formation rate available – but many are subject to extinction at high z Total amount of star-formation missed from UV surveys at such high redshifts remains uncertain… Star-formation history from Far-UV + IR high redshift samples (Left) Far-UV (Upper Right) IR (Lower Right) UV data critical in constraining s-f rate density models at high redshift Bouwers et al (2012) Schenker et al (2013) Madau & Dickinson (2014)

3. 10’  10’ L-Band field centred on GOODS-N 92 sources >40µJy. Observed 1996 - 1998 High resolution imaging can morphologically distinguish AGN & SF <70µJy population dominated by s-f galaxies typically at z<1.5  15’ diameter contiguous combination image 178 sources imaged with flux densities >5σ (beam corrected) Original MERLIN+VLA study of faint radio sources in GOODS-N J123634+621241 z=1.219 starburst False Colour: WFPC 2 Contours: Radio CI 10µJy/bm, 1σ=3.3µJy/bm Muxlow et al 2005 LAS peaks ~1.5” LAS peaks ~1.5” Wrigley et al in prep. Muxlow et al 2005 See poster by Wrigley et al 90% complete to 20µJy

4. e-MERGE Survey  full sampling of AGN & s-f galaxy radio luminosity function to z~5 >60 CO-Is from 9 countries Tier 0: Ian Smail [Durham], Tier 1: Tom Muxlow [Manchester] (Deep-narrow – 0.2 sq ο ) Tier 2: Ian McHardy [Southampton] (via PATT or SuperCLASS?) (Shallow-wide – 2.0 sq ο ) Tier 0 – 180hrs e-Merlin (L-band) + JVLA-A Tier 1 – 360hrs e-Merlin+40hrs JVA-A (L-band) + [Data Observed] 380hrs e-Merlin+ JVLA-A/B/C (C-band) mosaic [Some test data taken] A tiered e-Merlin + JVLA + EVN Legacy proposal A tiered e-Merlin + JVLA + EVN Legacy proposal The e-MERlin Galaxy Evolution Survey The e-MERlin Galaxy Evolution Survey Tier 0 – Normal galaxies out to z ~ 5 Tier 0 – Normal galaxies out to z ~ 5 Deep imaging around clusters to utilise amplification by lensing Tier 1 – Very deep survey of μJy radio source population Tier 1 – Very deep survey of μJy radio source population Deep imaging of the µJy radio sources in GOODS-N e-MERLIN Legacy programmes e-MERLIN Legacy programmes

5. Tier 1: New Ultra-Deep Study of GOODS-N e-MERLIN matches sensitivity of old (18 days) MERLIN in 24 hrs on source L-band: Single pointing centre, ~20 days including 76m Lovell telescope. Central 12 arcminute field 1  ~ 500nJy/beam (in combination with JVLA) Outer 30 arcminute field 1  ~ 1µJy/beam Lovell – 76m Knockin – 25m

6. Tier 1: New Ultra-Deep Study of GOODS-N e-MERLIN will image ~580 starbursts and ~270 AGN with an angular resolution of ~200 mas, complete to ~3µJy (>10 times deeper than the 2005 study) In the surrounding 800 square arcmins, e-MERLIN will image ~2500 star-forming galaxies and ~1200 AGN brighter than ~6µJy Ultra-deep C-band mosaic + ultra-deep EVN L-Band  AGN activity & feedback 580+270 2500+1200 >5000 sources in 0.2 square degree field >5000 sources in 0.2 square degree field Population synthesis: Matt Jarvis e-MERLIN matches sensitivity of old (18 days) MERLIN in 24 hrs on source L-band: Single pointing centre, ~20 days Central 12 arcminute field 1  ~ 500nJy/beam Outer 30 arcminute field 1  ~ 1µJy/beam

7. Original Global VLBI study confirmed AGN core-jets & AGN/starburst composites in high-z sub-mm sources. New ultra deep EVN study to 3µJy (EG078) over central region to study feedback from faint AGN in starbursts PI Mike Garrett – PhD Jack Radcliffe Chi et al 2013 Sub-mm AGN/Starburst composite at z=4.424 AGN core-jet in 20.6 mag elliptical galaxy at z=0.681 Muxlow et al 2005

8. Tier 1: New Ultra-Deep Study of GOODS-N JVLA C-band C-array mosaic JVLA L-Band Test e-Merlin L-band data (1.23-1.74GHz  full uv coverage) ~6 days elapsed, (~48 hrs on source with Lovell)+ 29 hrs JVLA A-array (~10% of Tier 1 e-Merlin allocation) Only a few classical radio galaxy structures – most AGN are small core-jets AGN Wide-angled tail radio galaxy (Total 5.3mJy) AGN Test Image

9. HST ACS: I=22.9 mag galaxy z=1.2653 Tier 1: New Ultra-Deep Study of GOODS-N JVLA C-band C-array Test e-Merlin L-band data + 29 hrs JVLA A-array (1.23-1.74GHz BW 512MHz) AGN Wide-angled tail radio galaxy (Total 5.3mJy) CI 10μJy/bm Peak 139 μJy/bm AGN Test Image

10. Test e-Merlin L-band data + 29 hrs JVLA A-array AGN Wide-angled tail radio galaxy (Total 5.3mJy) HST ACS: I=22.9 mag galaxy z=1.2653 Tier 1: New Ultra-Deep Study of GOODS-N JVLA C-band C-array J123725+621128 e-Merlin+JVLA 0.3” beam CI 7.5μJy/bm Peak 133 μJy/bm JVLA L-Band e-Merlin+JVLA L-Band New Image 300mas beam CI 7.5µJy/bm CI 10μJy/bm Peak 139 μJy/bm HST ACS: I=22.9 mag galaxy z=1.2653 Old Image AGN Test Image

11. Extended steep-spectrum ( α >1.62) starburst with embedded AGN? (S 1.4 = 393μJy). AGN variability between 1996 & 2013? L 1.4 =8.5x10 23 W/Hz  Star-formation rate ~200 M๏/yr (0.1-100M๏ assuming Salpeter IMF) Tier 1: New Ultra-Deep Study of GOODS-N JVLA L-Band e-Merlin test data +JVLA L-Band 1σ ~2.75µJy/bm - CI 6.2µJy/bm Peak 38µJy/bm Muxlow et al 2005 Starburst Test Image Old Image New Image

12. HST ACS: I=19.8 mag galaxy z=0.5032 Tier 1: New Ultra-Deep Study of GOODS-N e-Merlin test data +JVLA L-Band 1σ ~2.75µJy/bm - CI 6.2µJy/bm Peak 38µJy/bm Muxlow et al 2005 Extended steep-spectrum ( α >1.62) starburst with embedded AGN? (S 1.4 = 393μJy). AGN variability between 1996 & 2013? L 1.4 =8.5x10 23 W/Hz  Star-formation rate ~200 M๏/yr (0.1-100M๏ assuming Salpeter IMF) EG078 to look for faint radio core…. Bright galaxy core shows BL emission  Optical AGN activity Starburst Test Image Old Image New Image

13. Tier 1: New Ultra-Deep Study of GOODS-N Ultra wide-field data allows imaging to the edge of the outer field: 62mJy FR-II imaged (test data) – 10.4 arcminutes from field centre – 10.4 arcminutes from field centre e-Merlin L-Band JVLA L-Band

14. Seymour et al 2008 Haarsma et al 2000 Hopkins 2004 The co-moving Star- Formation Rate Density of the Universe from L-Band radio studies by Seymour et al (2008), Haarsma et al (2000), & UV, H α, Far-IR… Hopkins (2004) L-Band results from the e-MERGE survey will provide data for several thousand more sources  tightening the Seymour error bars by a factor ~4 & extending to z~5  tightening the Seymour error bars by a factor ~4 & extending to z~5 Does it stay flat to z~5 ? Star-formation History of the Universe - from Starburst Luminosities

15. Tier 0: Imaging sub-µJy galaxies Expect ~50 amplified sources with intrinsic fluxes as faint as 300nJy Measure faint radio counts May include SF galaxies with SFR~200M๏/yr to z~5 40µJ y 3µJy 0.3µJy ● Starburst Sub-mm Sub-mm A single L-Band pointing on a strong lensing cluster A2218 (z=0.18). A single L-Band pointing on a strong lensing cluster A2218 (z=0.18). Old MERLIN+VLA imaging Tier 1 imaging Tier 0 imaging (+Tier 1 stacking) (+Tier 1 stacking) e-MERGE will characterise the µJy & sub-µJy radio source population  the target population for the SKA in future high redshift SF studies