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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

Identification of High-redshift Galaxy Overdensities in GOODS-N and GOODS-S

The Astrophysical Journal American Astronomical Society 974:1 (2024) 41

Authors:

Jakob M Helton, Fengwu Sun, Charity Woodrum, Kevin N Hainline, Christopher NA Willmer, Marcia J Rieke, George H Rieke, Stacey Alberts, Daniel J Eisenstein, Sandro Tacchella, Brant Robertson, Benjamin D Johnson, William M Baker, Rachana Bhatawdekar, Andrew J Bunker, Zuyi Chen, Eiichi Egami, Zhiyuan Ji, Roberto Maiolino, Chris Willott, Joris Witstok

Abstract:

We conduct a systematic search for high-redshift galaxy overdensities at 4.9 < z spec < 8.9 in both the Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S fields using James Webb Space Telescope/Near-Infrared Camera (JWST/NIRCam) imaging from the JWST Advanced Deep Extragalactic Survey and JWST Extragalactic Medium-band Survey in addition to JWST/NIRCam wide field slitless spectroscopy from the First Reionization Epoch Spectroscopic Complete Survey. High-redshift galaxy candidates are identified using Hubble Space Telescope + JWST photometry spanning λ = 0.4–5.0 μm. We confirmed the redshifts for roughly a third of these galaxies using JWST spectroscopy over λ = 3.9–5.0 μm through identification of either Hα or OIIIλ5008 around the best-fit photometric redshift. The rest-ultraviolet magnitudes and continuum slopes of these galaxies were inferred from the photometry: the brightest and reddest objects appear in more dense environments and thus are surrounded by more galaxy neighbors than their fainter and bluer counterparts, suggesting accelerated galaxy evolution within overdense environments. We find 17 significant (δ gal ≥ 3.04, N gal ≥ 4) galaxy overdensities across both fields (seven in GOODS-N and 10 in GOODS-S), including the two highest redshift spectroscopically confirmed galaxy overdensities to date at zspec=7.954 and zspec=8.222 (representing densities around ∼6 and ∼12 times that of a random volume). We estimate the total halo mass of these large-scale structures to be 11.5≤log10Mhalo/M⊙≤13.4 using an empirical stellar mass-to-halo mass relation, which are likely underestimates as a result of incompleteness. These protocluster candidates are expected to evolve into massive galaxy clusters with log10Mhalo/M⊙≳14 by z = 0.
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JADES Ultrared Flattened Objects: Morphologies and Spatial Gradients in Color and Stellar Populations

The Astrophysical Journal American Astronomical Society 974:1 (2024) 48

Authors:

Justus L Gibson, Erica Nelson, Christina C Williams, Sedona H Price, Katherine E Whitaker, Katherine A Suess, Anna de Graaff, Benjamin D Johnson, Andrew J Bunker, William M Baker, Rachana Bhatawdekar, Kristan Boyett, Stephane Charlot, Emma Curtis-Lake, Daniel J Eisenstein, Kevin Hainline, Ryan Hausen, Roberto Maiolino, George Rieke, Marcia Rieke, Brant Robertson, Sandro Tacchella, Chris Willott

Abstract:

One of the more surprising findings after the first year of JWST observations is the large number of spatially extended galaxies (ultrared flattened objects, or UFOs) among the optically faint galaxy (OFG) population otherwise thought to be compact. Leveraging the depth and survey area of the JWST Advanced Deep Extragalactic Survey, we extend observations of the OFG population to an additional 112 objects, 56 of which are well-resolved in F444W with effective sizes, R e > 0.″25, more than tripling previous UFO counts. These galaxies have redshifts around 2 < z < 4, high stellar masses ( log(M*/M⊙)∼10–11 ), and star formation rates around ∼100–1000 M ⊙ yr−1. Surprisingly, UFOs are red across their entire extents, which spatially resolved analysis of their stellar populations shows is due to large values of dust attenuation (typically A V > 2 mag even at large radii). Morphologically, the majority of our UFO sample tends to have low Sérsic indices (n ∼ 1) suggesting that these large, massive, OFGs have little contribution from a bulge in F444W. Further, a majority have axis ratios between 0.2 < q < 0.4, which Bayesian modeling suggests that their intrinsic shapes are consistent with being a mixture of inclined disks and prolate objects with little to no contribution from spheroids. While kinematic constraints will be needed to determine the true intrinsic shapes of UFOs, it is clear that an unexpected population of large, disky or prolate objects contributes significantly to the population of OFGs.
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A biconical ionised gas outflow and evidence of positive feedback in NGC 7172 uncovered by MIRI/JWST

Astronomy & Astrophysics EDP Sciences 690 (2024) a350

Authors:

L Hermosa Muñoz, A Alonso-Herrero, M Pereira-Santaella, I García-Bernete, S García-Burillo, B García-Lorenzo, R Davies, T Shimizu, D Esparza-Arredondo, EKS Hicks, H Haidar, M Leist, E López-Rodríguez, C Ramos Almeida, D Rosario, L Zhang, A Audibert, E Bellocchi, P Boorman, AJ Bunker, F Combes, S Campbell, T Díaz-Santos, L Fuller, P Gandhi, O González-Martín, S Hönig, M Imanishi, T Izumi, A Labiano, NA Levenson, C Packham, C Ricci, D Rigopoulou, D Rouan, M Stalevski, M Villar-Martín, MJ Ward
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A new census of dust and polycyclic aromatic hydrocarbons at z = 0.7–2 with JWST MIRI

Astronomy & Astrophysics EDP Sciences 690 (2024) a89

Authors:

Irene Shivaei, Stacey Alberts, Michael Florian, George Rieke, Stijn Wuyts, Sarah Bodansky, Andrew J Bunker, Alex J Cameron, Mirko Curti, Francesco D’Eugenio, Ugnė Dudzevičiūtė, Zhiyuan Ji, Benjamin D Johnson, Ivan Kramarenko, Jianwei Lyu, Jorryt Matthee, Jane Morrison, Rohan Naidu, Pablo G Pérez-González, Naveen Reddy, Brant Robertson, Yang Sun, Sandro Tacchella, Katherine Whitaker, Christina C Williams, Christopher NA Willmer, Joris Witstok, Mengyuan Xiao, Yongda Zhu
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JADES NIRSpec initial data release for the Hubble Ultra Deep Field

Astronomy & Astrophysics EDP Sciences 690 (2024) a288

Authors:

Andrew J Bunker, Alex J Cameron, Emma Curtis-Lake, Peter Jakobsen, Stefano Carniani, Mirko Curti, Joris Witstok, Roberto Maiolino, Francesco D’Eugenio, Tobias J Looser, Chris Willott, Nina Bonaventura, Kevin Hainline, Hannah Übler, Christopher NA Willmer, Aayush Saxena, Renske Smit, Stacey Alberts, Santiago Arribas, William M Baker, Stefi Baum, Rachana Bhatawdekar, Rebecca AA Bowler, Kristan Boyett, Stephane Charlot, Zuyi Chen, Jacopo Chevallard, Chiara Circosta, Christa DeCoursey, Anna de Graaff, Eiichi Egami, Daniel J Eisenstein, Ryan Endsley, Pierre Ferruit, Giovanna Giardino, Ryan Hausen, Jakob M Helton, Raphael E Hviding, Zhiyuan Ji, Benjamin D Johnson, Gareth C Jones, Nimisha Kumari, Isaac Laseter, Nora Lützgendorf, Michael V Maseda, Erica Nelson, Eleonora Parlanti, Michele Perna, Bernard J Rauscher, Tim Rawle, Hans-Walter Rix, Marcia Rieke, Brant Robertson, Bruno Rodríguez Del Pino, Lester Sandles, Jan Scholtz, Katherine Sharpe, Maya Skarbinski, Daniel P Stark, Fengwu Sun, Sandro Tacchella, Michael W Topping, Natalia C Villanueva, Imaan EB Wallace, Christina C Williams, Charity Woodrum
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