Deep ATLAS Radio Observations of the Chandra Deep Field?South/<i>Spitzer</i>Wide?Area Infrared Extragalactic Field

Norris, R. P.; Afonso, J.; Appleton, P. N.; Boyle, Brian J.; Ciliegi, P.; Croom, S. M.; Huynh, Minh; Jackson, C. A.; Koekemoer, Anton M.; Lonsdale, C. J.; Middelberg, E.; Mobasher, Bahram; Oliver, Seb; Polletta, M.; Siana, Brian; Smail, Ian; Voronkov, Maxim

doi:10.1086/508275

Cited by 209 publications

(471 citation statements)

References 47 publications

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“…Most of the VLBA-detected sources (14 sources) are compact, which is indicated by the ratio of VLBI-scale flux density to the ATCA-scale flux density being consistent with unity (see Table 3). We note, however, that the ATCA flux densities by Norris et al (2006) are probably affected by clean bias, which tends to underestimate the flux densities of weak sources. For a very similar observation, Middelberg et al (2008a) show that clean bias can decrease the flux density by up to 5% for sources with SNR smaller than 20.…”

Section: Detectionsmentioning

confidence: 71%

“…However, even with novel processing techniques it was not possible to image the entire area contained within the antennas' primary beams, nor would this be a promising exercise, since any flux detected in the VLBI observations must have been detected in existing compact-array interferometry data because of their sensitivity to lower-brightness temperature sources 1 . We therefore used the ATCA observations published by Norris et al (2006) as an input catalogue, and aimed at imaging all 96 targets from that catalogue in a region centred on the GOODS/CDFS and contained within the VLBA primary beam area. An overview of the observed field is given in Fig.…”

Section: The Target Sourcesmentioning

confidence: 99%

“…To determine whether a source is already a known AGN we used the information from various sources listed in Norris et al (2006) and the criteria by Szokoly et al (2004) (using the X-ray hardness ratio and X-ray luminosity, see Sect. 5.2.3).…”

Section: New Agnmentioning

confidence: 99%

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Wide-field VLBA observations of theChandradeep field South

Middelberg

Deller

Morgan

et al. 2010

A&A

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Context. Wide-field surveys are a commonly-used method for studying thousands of objects simultaneously, to investigate, e.g., the joint evolution of star-forming galaxies and active galactic nuclei. Very long baseline interferometry (VLBI) observations can yield valuable input for such studies because they are able to identify AGN unambiguously in the moderate-to-high-redshift Universe. However, VLBI observations of large swaths of the sky are impractical using standard methods, because the fields of view of VLBI observations are on the order of 10 or less, and have therefore so far only played a minor role in galaxy evolution studies. Aims. We have embarked on a project to carry out Very Long Baseline Array (VLBA) observations of all 96 known radio sources in one of the best-studied areas in the sky, the Chandra deep field South (CDFS). The challenge was to develop methods that could significantly reduce the amount of observing (and post-processing) time, making such a project feasible. Methods. We developed an extension to the DiFX software correlator that allows one to efficiently correlate up to hundreds of positions within the primary beams of the interferometer antennas. This extension enabled us to target many sources simultaneously, at full resolution and high sensitivity, using only a small amount of observing time. The combination of wide fields-of-view and high sensitivity across the field in this survey is unprecedented. Results. We observed a single pointing containing the CDFS with the VLBA, in which 96 radio sources were known from previous observations with the Australia Telescope Compact Array (ATCA). From our input sample of 96 sources, 20 were detected with the VLBA, and one more source was tentatively detected. The majority of these objects have flux densities in agreement with arcsec-scale observations, implying that their radio emission comes from very small regions. Two objects are visibly resolved. One VLBI-detected object had been classified earlier as a star-forming galaxy. After comparing the VLBI detections to sources found in sensitive, colocated X-ray observations, we find that X-ray detections are not a good indicator for VLBI detections. Conclusions. We have successfully demonstrated a new extension to the DiFX software correlator, allowing one to observe hundreds of fields of view simultaneously. In a sensitive observation of the CDFS we detect 21% of the sources and were able to reclassify 7 sources as AGN, which had not been identified as such before. Wide-field VLBI survey science is now coming of age.

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Section: Detectionsmentioning

confidence: 71%

Section: The Target Sourcesmentioning

confidence: 99%

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Wide-field VLBA observations of theChandradeep field South

Middelberg

Deller

Morgan

et al. 2010

A&A

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“…The source is also reported in the ATLAS survey (carried out with ATCA) by Norris et al (2006) and Hales et al (2014) at 20 cm with a different resolution (∼11 × 5 and ∼12 × 6 , respectively). The flux densities reported in the two ATCAbased papers for the western lobe are 44.9 ± 9.0 mJy and 55.4 ± 2.8 mJy, respectively, while those for eastern lobe are 27.4 ± 5.5 mJy and 38.8 ± 1.9 mJy, respectively.…”

Section: Radio Datamentioning

confidence: 99%

The XMM deep survey in the CDF-S

Vignali

Iwasawa

Comastri

et al. 2015

A&A

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In active galactic nuclei (AGN)-galaxy co-evolution models, AGN winds and outflows are often invoked to explain why super-massive black holes and galaxies stop growing efficiently at a certain phase of their lives. They are commonly referred to as the leading actors of feedback processes. Evidence of ultra-fast (v > ∼ 0.05c) outflows in the innermost regions of AGN has been collected in the past decade by sensitive X-ray observations for sizable samples of AGN, mostly at low redshift. Here we present ultra-deep XMM-Newton and Chandra spectral data of an obscured (N H ≈ 2 × 10 23 cm −2 ), intrinsically luminous (L 2−10 keV ≈ 4 × 10 44 erg s −1 ) quasar (named PID352) at z ≈ 1.6 (derived from the X-ray spectral analysis) in the Chandra Deep Field-South. The source is characterized by an iron emission and absorption line complex at observed energies of E ≈ 2−3 keV. While the emission line is interpreted as being due to neutral iron (consistent with the presence of cold absorption), the absorption feature is due to highly ionized iron transitions (FeXXV, FeXXVI) with an outflowing velocity of 0.14 +0.02 −0.06 c, as derived from photoionization models. The mass outflow rate -∼2 M yr −1 -is similar to the source accretion rate, and the derived mechanical energy rate is ∼9.5 × 10 44 erg s −1 , corresponding to 9% of the source bolometric luminosity. PID352 represents one of the few cases where indications of X-ray outflowing gas have been observed at high redshift thus far. This wind is powerful enough to provide feedback on the host galaxy.

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“…For these sources, the ratio of radio to 3.6 µm fluxes can easily be above 50. Such USS sources are then also classified as Infrared-Faint Radio Sources (IFRS), a rare class of object first identified in the Australia Telescope Large Area Survey (Norris et al 2006). Recent follow-up studies have provided strong indications that the IFRS population probably contains a majority of obscured, highredshift, radio-loud galaxies (Norris et al 2007;Middelberg et al 2008;Huynh et al 2010;Norris et al 2010).…”

Section: Photometric Redshiftsmentioning

confidence: 99%