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

Seungyoup ChiKapteyn Institute (RuG) / JIVE

Collaborators :

M. A. Garrett, P. D. Barthel et al.

8th EVN Symposium 2006

Torun, Poland, 26-29 September 2006

ContentsContents

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

Hubble Deep Field North (HDF-N)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…

Richards et al. 1998

Previous results in HDF-NPrevious 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 ~ 3.3 μJy/beam

Previous results in HDF-NPrevious 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

Global VLBI observationGlobal VLBI observationObservation : 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 HFFsTotal 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).

VLA J123642+621331 VLA J123642+621331

locate just outside the HDF

Richard et al. 1988

VLA J123642+621331 VLA J123642+621331

locate just outside the HDF

No optical counterpart to I ≤ 25 mag.

a) WFPC2 (I-band)

b) NICMOS F110W (3-orbits)

c) NICMOS F160W (6-orbits)

d) KPNO 4-m

(Waddington et al. 1999)

VLA J123642+621331 VLA J123642+621331

locate just outside the HDF

No optical counterpart to I ≤ 25 mag.

Keck spectra : Lyα at z=4.424

Waddington et al. 1999

VLA J123642+621331 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)

Brandt et al. 2001

VLA J123642+621331 VLA J123642+621331

VLA/MERLIN

1.4 GHz

(Muxlow et al.

2005)

EVN 1.6 GHz

(Garrett et al.

2001)

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 J123642+621331 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

Garrett 2001

VLA J123642+621331 VLA J123642+621331

Richard et al. 1988

Other detections in HDF Other detections in HDF (VLA J123644+621133)(VLA J123644+621133)

-FR-1 radio galaxy

-flat spectrum α=0.1

-elliptical gal. at z = 1.050

Other detections in HDF Other detections in HDF (VLA J123646+621404)(VLA J123646+621404)

Richard et al. 1988

-inverted spectrum (α = - 0.04)

-compact + two-sided ext. emission

-face-on disk gal. at z = 0.961

VLA 123652+621444VLA 123652+621444 New detection!!!New detection!!!

Richard et al. 1988

VLA 123652+621444VLA 123652+621444 New detection!!!New detection!!!

locate just outside of HDF

I = 18.5 mag. elliptical

X-ray counterpart

Brandt et al. 2001

VLA 123652+621444VLA 123652+621444 New detection!!!New detection!!!

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

Summary & Future workSummary & Future work

reach to r.m.s. ~ 7.3 μJy/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)

co-add imagesco-add images

~ 16 μJy/beam

~ 17 μJy/beam

~ 12 μJy/beam