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Deep, wide-field global VLBI observations of HDF-N

Deep, wide-field global VLBI observations of HDF-N. Seungyoup Chi Kapteyn Institute (RuG) / JIVE Collaborators : M. A. Garrett, P. D. Barthel et al. 8th EVN Symposium 2006 Torun, Poland, 26 - 29 September 2006. Contents. Introduction to HDF Previous results (MERLIN and EVN)

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Deep, wide-field global VLBI observations of HDF-N

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  1. Deep, wide-field global VLBI observations of HDF-N Seungyoup Chi Kapteyn Institute (RuG) / JIVE Collaborators : M. A. Garrett, P. D. Barthel et al. 8th EVN Symposium 2006 Torun, Poland, 26-29 September 2006

  2. Contents • Introduction to HDF • Previous results (MERLIN and EVN) • New Global VLBI observations • VLA J123642+621331 – starburst / AGN ? • Other detections in HDF-N • Summary and Future work

  3. Richards et al. 1998 Hubble Deep Field North (HDF-N) • 10 days of HST time • Imaged 2.5'× 2.5' of sky • Depth (I-band) : ~ 28 mag. • High resolution : ~ 40 mas • Flanking fields : ~ 25 mag. • Follow-up observations - Sub-mm, IR, X-ray, Radio, Ground-based opt. imaging, Spectroscopy…

  4. Previous results in HDF-N • MERLIN+VLA 1.4 GHz obs. (Muxlow et al. 2005) - 10-arcmin field - 92 radio source (S1.4 > 40 μJy) - noise level ~ 3.3μJy/beam

  5. Previous results in HDF-N • EVN 1.6 GHz obs. (Garrett et al. 2001) - 6 (MERLIN) targets - noise level ~ 30 μJy/beam (in dirty maps) - 3 detections

  6. Global VLBI observation • Observation : 20 ~ 22 February 2004 (3 × 12 hrs.) • 2 x 8 MHz (RR, LL), 2-bit samples [128 Mbps recording rate] • EVN disk recording; VLBA on tape. • 16 telescope array including 100-m Greenbank and Effelsberg telescopes, plus 76-m Lovell telescope. • Frequency : 1.4 GHz  Max. Angular resolution : ~ 4 mas (in HDF-N), increasing taper in HFF. • Data Correlated at JIVE: • Correlator running at full throttle… • Each (1 x 8 MHz) polarisation channel correlated in a separate pass in order to maximise spectral resolution (minimise bandwidth smearing) • Wide-field approach and techniques used to image out entire HDF-N and HFFs • Total data size : ~ 800 Gbytes (3 epochs, 6 Ifs, 256 sp ch/IF; 0.25 second int. time) • Images from each IF are co-added together. • Image Noise level: for a single IF ~ 17 μJy/beam for all 6 Ifs (full data set) reaching ~ 7.3 μJy/ beam in HDF-N (larger in HFF).

  7. Richard et al. 1988 VLA J123642+621331 • locate just outside the HDF

  8. WFPC2 (I-band) • NICMOS F110W (3-orbits) • NICMOS F160W (6-orbits) • KPNO 4-m • (Waddington et al. 1999) VLA J123642+621331 • locate just outside the HDF • No optical counterpart to I ≤ 25 mag.

  9. Waddington et al. 1999 VLA J123642+621331 • locate just outside the HDF • No optical counterpart to I ≤ 25 mag. • Keck spectra : Lyα at z=4.424

  10. Brandt et al. 2001 VLA J123642+621331 • locate just outside the HDF • No optical counterpart to I ≤ 25 mag. • Keck spectra : Lyα at z=4.424 • Chandra X-ray (0.5 ~ 2.0 keV)

  11. VLA J123642+621331 • locate just outside the HDF • No optical counterpart to I ≤ 25 mag. • Keck spectra : Lyα at z=4.424 • Chandra X-ray (0.5 ~ 2.0 keV) • radio structure : compact comp. + extended emission VLA/MERLIN 1.4 GHz (Muxlow et al. 2005) EVN 1.6 GHz (Garrett et al. 2001)

  12. Garrett 2001 VLA J123642+621331 • locate just outside the HDF • No optical counterpart to I ≤ 25 mag. • Keck spectra : Lyα at z=4.424 • Chandra X-ray (0.5 ~ 2.0 keV) • radio structure : compact comp. + extended emission • radio loud  powered by AGN

  13. VLA J123642+621331

  14. Richard et al. 1988 Other detections in HDF (VLA J123644+621133) • FR-1 radio galaxy • flat spectrum α=0.1 • elliptical gal. at z = 1.050

  15. Richard et al. 1988 Other detections in HDF (VLA J123646+621404) • inverted spectrum (α = - 0.04) • compact + two-sided ext. emission • face-on disk gal. at z = 0.961

  16. Richard et al. 1988 New detection!!! VLA 123652+621444

  17. Brandt et al. 2001 New detection!!! VLA 123652+621444 • locate just outside of HDF • I = 18.5 mag. elliptical • X-ray counterpart

  18. New detection!!! VLA 123652+621444 • locate just outside of HDF • I = 18.5 mag. elliptical • X-ray counterpart • inverted spectrum α = - 0.5 vary in intensity  AGN at z = 0.321 • compact core + one- sided jet-like feature to the east ~ 1.3 arcsec

  19. Summary & Future work • reach to r.m.s. ~ 7.3μJy/beam • 4 detections (7 targets in HDF and adjacent HFF) ; one new detection • Analyse the rest of the HFFs (85 radio source targets!)  provide deep and high-resolution radio source samples • New data: • 1 Gbps 6cm Global VLBI on VLA J123642+621331 • Target additional deep field region with VLBI (probably Spitzer FLSv)

  20. ~ 16 μJy/beam ~ 12 μJy/beam ~ 17 μJy/beam co-add images

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