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dc.contributor.authorMoss, V.
dc.contributor.authorAllison, J.
dc.contributor.authorSadler, E.
dc.contributor.authorUrquhart, R.
dc.contributor.authorSoria, Roberto
dc.contributor.authorCallingham, J.
dc.contributor.authorCurran, S.
dc.contributor.authorMusaeva, A.
dc.contributor.authorMahony, E.
dc.contributor.authorGlowacki, M.
dc.contributor.authorFarrell, S.
dc.contributor.authorBannister, K.
dc.contributor.authorChippendale, A.
dc.contributor.authorEdwards, P.
dc.contributor.authorHarvey-Smith, L.
dc.contributor.authorHeywood, I.
dc.contributor.authorHotan, A.
dc.contributor.authorIndermuehle, B.
dc.contributor.authorLenc, E.
dc.contributor.authorMarvil, J.
dc.contributor.authorMcConnell, D.
dc.contributor.authorReynolds, J.
dc.contributor.authorVoronkov, M.
dc.contributor.authorWark, R.
dc.contributor.authorWhiting, M.
dc.identifier.citationMoss, V. and Allison, J. and Sadler, E. and Urquhart, R. and Soria, R. and Callingham, J. and Curran, S. et al. 2017. Connecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN. Monthly Notices of the Royal Astronomical Society. 471 (3): pp. 2952-2973.

Many radio galaxies show the presence of dense and dusty gas near the active nucleus. This can be traced by both 21 cm H I absorption and soft X-ray absorption, offering new insight into the physical nature of the circumnuclear medium of these distant galaxies. To better understand this relationship, we investigate soft X-ray absorption as an indicator for the detection of associated H I absorption, as part of preparation for the First Large Absorption Survey in H I to be undertaken with the Australian Square Kilometre Array Pathfinder (ASKAP). We present the results of our pilot study using the Boolardy Engineering Test Array, a precursor to ASKAP, to search for new absorption detections in radio sources brighter than 1 Jy that also feature soft X-ray absorption. Based on this pilot survey, we detected H I absorption towards the radio source PKS 1657−298 at a redshift of z = 0.42. This source also features the highest X-ray absorption ratio of our pilot sample by a factor of 3, which is consistent with our general findings that X-ray absorption predicates the presence of dense neutral gas. By comparing the X-ray properties of active galactic nuclei with and without detection of H I absorption at radio wavelengths, we find that X-ray hardness ratio and H I absorption optical depth are correlated at a statistical significance of 4.71σ. We conclude by considering the impact of these findings on future radio and X-ray absorption studies.

dc.publisherOxford University Press
dc.titleConnecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN
dc.typeJournal Article
dcterms.source.titleMonthly Notices of the Royal Astronomical Society

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

curtin.departmentCurtin Institute of Radio Astronomy (Physics)
curtin.accessStatusOpen access

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