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Black Hole

Lensing of space time around a black hole. At Oxford we study black holes observationally and theoretically on all size and time scales - it is some of our core work.

Credit: ALAIN RIAZUELO, IAP/UPMC/CNRS. CLICK HERE TO VIEW MORE IMAGES.

Andrew Bunker

Professor of Astrophysics

Research theme

  • Astronomy and astrophysics

Sub department

  • Astrophysics

Research groups

  • Galaxy formation and evolution
Andy.Bunker@physics.ox.ac.uk
Telephone: 01865 (2)83126
Denys Wilkinson Building, room 702
  • About
  • Publications

To High Redshift and Low Mass: Exploring the Emergence of Quenched Galaxies and Their Environments at 3 < z < 6 in the Ultra-deep JADES MIRI F770W Parallel

The Astrophysical Journal American Astronomical Society 975:1 (2024) 85

Authors:

Stacey Alberts, Christina C Williams, Jakob M Helton, Katherine A Suess, Zhiyuan Ji, Irene Shivaei, Jianwei Lyu, George Rieke, William M Baker, Nina Bonaventura, Andrew J Bunker, Stefano Carniani, Stephane Charlot, Emma Curtis-Lake, Francesco D’Eugenio, Daniel J Eisenstein, Anna de Graaff, Kevin N Hainline, Ryan Hausen, Benjamin D Johnson, Roberto Maiolino, Eleonora Parlanti, Marcia J Rieke, Brant E Robertson

Abstract:

We present the robust selection of high-redshift quiescent galaxies (QG) and poststarburst (PSB) galaxies using ultra-deep NIRCam and MIRI imaging from the JWST Advanced Deep Extragalactic Survey (JADES). At 3 < z < 6, MIRI 7.7 μm imaging provides rest-frame J band, which is commonly used to break the degeneracy between old stellar populations and dust attenuation at lower redshifts. We identify 23 passively evolving galaxies in UVJ color space in a mass-limited (log M ⋆/M ⊙ ≥ 8.5) sample over 8.8 arcmin2. An evaluation of the contribution of the 7.7 μm shows that JADES-like NIRCam coverage (9+ photometric bands) can compensate for lacking the J band at these redshifts; however, more limited three-band selections perform better with MIRI. Our sample is characterized by rapid quenching timescales (∼100–600 Myr) with formation redshifts z f ≲ 9 and includes a potential record-holding massive QG at zphot=5.33−0.17+0.16 and two QGs with evidence for significant residual dust content (A V ∼ 1–2). In addition, we present a large sample of 12 log M ⋆/M ⊙ = 8.5–9.5 PSBs, demonstrating that UVJ selection can be extended to low mass. An analysis of the environment of our sample reveals that the group known as the Cosmic Rose contains a massive QG and a dust-obscured star-forming galaxy (a so-called Jekyll and Hyde pair) plus three additional QGs within ∼20 kpc. Moreover, the Cosmic Rose is part of a larger overdensity at z ∼ 3.7, which contains 7/12 of our low-mass PSBs. Another four low-mass PSBs are members of an overdensity at z ∼ 3.4; this result strongly indicates low-mass PSBs are preferentially associated with overdense environments at z > 3.
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Characterising the z $\sim$ 7.66 Type-II AGN candidate SMACS S06355 using BEAGLE-AGN and JWST NIRSpec/NIRCam

(2024)

Authors:

MS Silcock, E Curtis-Lake, DJB Smith, IEB Wallace, A Vidal-García, A Plat, M Hirschmann, A Feltre, J Chevallard, S Charlot, S Carniani, AJ Bunker
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Polycyclic Aromatic Hydrocarbon Emission in the Central Regions of Three Seyferts and the Implication for Underlying Feedback Mechanisms

The Astrophysical Journal Letters American Astronomical Society 975:1 (2024) L2

Authors:

Lulu Zhang, Ismael García-Bernete, Chris Packham, Fergus R Donnan, Dimitra Rigopoulou, Erin KS Hicks, Ric I Davies, Taro T Shimizu, Almudena Alonso-Herrero, Cristina Ramos Almeida, Miguel Pereira-Santaella, Claudio Ricci, Andrew J Bunker, Mason T Leist, David J Rosario, Santiago García-Burillo, Laura Hermosa Muñoz, Francoise Combes, Masatoshi Imanishi, Alvaro Labiano, Donaji Esparza-Arredondo, Enrica Bellocchi, Anelise Audibert, Lindsay Fuller

Abstract:

We analyze JWST Mid-Infrared Instrument/Medium Resolution Spectrograph integral field unit observations of three Seyferts from the Galactic Activity, Torus, and Outflow Survey (GATOS) and showcase the intriguing polycyclic aromatic hydrocarbon (PAH) and emission-line characteristics in regions of ∼500 pc scales over or around their active galactic nuclei (AGN). Combing the measurements and model predictions, we find that the central regions containing a high fraction of neutral PAHs with small sizes, e.g., those in ESO137-G034, are in highly heated environments, due to collisional shock heating, with hard and moderately intense radiation fields. Such environments are proposed to result in inhibited growth or preferential erosion of PAHs, decreasing their average size and overall abundance. We additionally find that the central regions containing a high fraction of ionized PAHs with large sizes, e.g., those in MCG-05-23-016, are likely experiencing severe photoionization because of the radiative effects from the radiative shock precursor besides the AGN. The severe photoionization can contribute to the ionization and further destruction of PAHs. Overall, different Seyferts, even different regions in the same galaxy, e.g., those in NGC 3081, can contain PAH populations of different properties. Specifically, Seyferts that exhibit similar PAH characteristics to ESO137-G034 and MCG-05-23-016 also tend to have similar emission-line properties to them, suggesting that the explanations for PAH characteristics of ESO137-G034 and MCG-05-23-016 may also apply generally. These results have promising application in the era of JWST, especially in diagnosing different (i.e., radiative and kinetic) AGN feedback modes.
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SMILES: Discovery of Higher Ionizing Photon Production Efficiency in Overdense Regions

(2024)

Authors:

Yongda Zhu, Stacey Alberts, Jianwei Lyu, Jane Morrison, George H Rieke, Yang Sun, Jakob M Helton, Zhiyuan Ji, Rachana Bhatawdekar, Nina Bonaventura, Andrew J Bunker, Xiaojing Lin, Marcia J Rieke, Pierluigi Rinaldi, Irene Shivaei, Christopher NA Willmer, Junyu Zhang
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The abundance and nature of high-redshift quiescent galaxies from JADES spectroscopy and the FLAMINGO simulations

(2024)

Authors:

William M Baker, Seunghwan Lim, Francesco D'Eugenio, Roberto Maiolino, Zhiyuan Ji, Santiago Arribas, Andrew J Bunker, Stefano Carniani, Stephane Charlot, Anna de Graaff, Kevin Hainline, Tobias J Looser, Jianwei Lyu, Pierluigi Rinaldi, Brant Robertson, Matthieu Schaller, Joop Schaye, Jan Scholtz, Hannah Ubler, Christina C Williams, Christopher NA Willmer, Chris Willott, Yongda Zhu
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