Christopher P. O'Dea

Prof. Dr. Christopher P. O'Dea

Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Research Focus & Metrics

Academic Career Length

35Years (1992-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 January 2020 in Publications of the Astronomical Society of the Pacific
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Journal Article
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MLMark Lacy
Mark Lacy
SBS. A. Baum
S. A. Baum
CCC. J. Chandler
C. J. Chandler
SCS. Chatterjee
S. Chatterjee
TCT. E. Clarke
T. E. Clarke
IYI. Yoon
I. Yoon

30 March 2021 in The Astronomy and Astrophysics Review
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Journal Article
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Christopher P. O'DeaChristopher P. O'Dea
Christopher P. O'Dea
DSDhruba Jyoti Saikia
Dhruba Jyoti Saikia

1 August 2021 in The Astrophysical Journal Supplement Series
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Journal Article
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YGYjan A. Gordon
Yjan A. Gordon
MBMichelle M. Boyce
Michelle M. Boyce
Christopher P. O'DeaChristopher P. O'Dea
Christopher P. O'Dea
LRLawrence Rudnick
Lawrence Rudnick
HAHeinz Andernach
Heinz Andernach
ISIsabel Sander
Isabel Sander
The Very Large Array Sky Survey (VLASS) is observing the entire sky north of −40° in the S band (2 GHz < ν < 4 GHz), with the highest angular resolution (2.″5) of any all-sky radio continuum survey to date. VLASS will cover its entire footprint over three distinct epochs, the first of which has now been observed in full. Based on Quick Look images from this first epoch, we have created a catalog of 1.9 × 106 reliably detected radio components. Due to the limitations of the Quick Look images, component flux densities are underestimated by ∼15% at S peak > 3 mJy beam−1 and are often unreliable for fainter components. We use this catalog to perform statistical analyses of the ν ∼ 3 GHz radio sky. Comparisons with the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey show the typical 1.4–3 GHz spectral index, α, to be ∼−0.71. The radio color–color distribution of point and extended components is explored by matching with FIRST and the LOFAR Two-meter Sky Survey. We present the VLASS source counts, dN/dS, which are found to be consistent with previous observations at 1.4 and 3 GHz. Resolution improvements over FIRST result in excess power in the VLASS two-point correlation function at angular scales ≲7″, and in 18% of active galactic nuclei associated with a single FIRST component being split into multicomponent sources by VLASS.

17 September 2018 in The Astrophysical Journal
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GTGrant Tremblay
Grant Tremblay
FCFrancoise Combes
Francoise Combes
JOJ. B. R. Oonk
J. B. R. Oonk
HRH. R. Russell
H. R. Russell
MMM. A. McDonald
M. A. McDonald
JZJ. A. ZuHone
J. A. ZuHone
We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy’s core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning “fountain,” wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales.

15 September 2016 in The Astrophysical Journal Letters
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JGJack F. Gallimore
Jack F. Gallimore
MEMoshe ELITZUR
Moshe ELITZUR
RMRoberto Maiolino
Roberto Maiolino
AMAlessandro Marconi
Alessandro Marconi
Christopher P. O'DeaChristopher P. O'Dea
Christopher P. O'Dea
ESEleonora Sani
Eleonora Sani
We have detected in ALMA observations CO emission from the nucleus of the Seyfert galaxy NGC 1068. The low-velocity (up to ±70 km s−1 relative to systemic) CO emission resolves into a 12 × 7 pc structure, roughly aligned with the nuclear radio source. Higher-velocity emission (up to ±400 km s−1) is consistent with a bipolar outflow in a direction nearly perpendicular (≃80°) to the nuclear disk. The position–velocity diagram shows that in addition to the outflow, the velocity field may also contain rotation about the disk axis. These observations provide compelling evidence in support of the disk-wind scenario for the active galactic nucleus obscuring torus.

14 October 2019 in The Astrophysical Journal Letters
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Journal Article
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CIC. M. Violette Impellizzeri
C. M. Violette Impellizzeri
JGJack F. Gallimore
Jack F. Gallimore
SBStefi A. Baum
Stefi A. Baum
MEMoshe ELITZUR
Moshe ELITZUR
RDRichard Davies
Richard Davies
ESEleonora Sani
Eleonora Sani
We present 1.4 pc resolution observations of 256 GHz nuclear radio continuum and HCN (J = 3 → 2) in the molecular torus of NGC 1068. The integrated radio continuum emission has a flat spectrum consistent with free–free emission and resolves into an X-shaped structure resembling an edge-brightened bicone. HCN is detected in absorption against the continuum, and the absorption spectrum shows a pronounced blue wing that suggests a high-velocity molecular outflow with speeds reaching 450 km s−1. Analysis of the off-nucleus emission line kinematics and morphology reveals two nested, rotating disk components. The inner disk, inside r ∼ 1.2 pc, has kinematics that are consistent with the nearly edge-on, geometrically thin H2O megamaser disk in Keplerian rotation around a central mass of 1.66 × 107 M ⊙. The outer disk, which extends to ∼7 pc radius, counter-rotates relative to the inner disk. The rotation curve of the outer disk is consistent with rotation around the same central mass as the megamaser disk but in the opposite sense. The morphology of the molecular gas is asymmetric around the nuclear continuum source. We speculate that the outer disk formed from more recently introduced molecular gas falling out of the host galaxy or from a captured dwarf satellite galaxy. In NGC 1068, we find direct evidence that the molecular torus consists of counter-rotating and misaligned disks on parsec scales.