Browsing by Author "Geach, James E."

Now showing items 1-20 of 25

    • A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy 

      Rupke, David S.~N.; Coil, Alison; Geach, James E.; Tremonti, Christy; Diamond-Stanic, Aleksandar M.; George, Erin R.; Hickox, Ryan C.; Kepley, Amanda A.; Leung, Gene; Moustakas, John; Rudnick, Gregory; Sell, Paul H. (2019-10-31)
      Ninety per cent of baryons are located outside galaxies, either in the circumgalactic or intergalactic medium1,2. Theory points to galactic winds as the primary source of the enriched and massive circumgalactic medium3,4,5,6. ...

    • Astronomia ex machina: a history, primer and outlook on neural networks in astronomy 

      Smith, Michael J.; Geach, James E. (2023-05-31)
      In this review, we explore the historical development and future prospects of artificial intelligence (AI) and deep learning in astronomy. We trace the evolution of connectionism in astronomy through its three waves, from ...

    • AstroVaDEr: Astronomical Variational Deep Embedder for Unsupervised Morphological Classification of Galaxies and Synthetic Image Generation 

      Spindler, Ashley; Geach, James E.; Smith, Michael J. (2021-03-01)
      We present AstroVaDEr (Astronomical Variational Deep Embedder), a variational autoencoder designed to perform unsupervised clustering and synthetic image generation using astronomical imaging catalogues. The model is a ...

    • An automatic taxonomy of galaxy morphology using unsupervised machine learning 

      Hocking, Alex; Geach, James E.; Sun, Yi; Davey, Neil (2017-09-15)
      We present an unsupervised machine learning technique that automatically segments and labels galaxies in astronomical imaging surveys using only pixel data. Distinct from previous unsupervised machine learning approaches ...

    • The case for a 'sub-millimeter SDSS' : a 3D map of galaxy evolution to z~10 

      Geach, James E.; Banerji, Manda; Bertoldi, Frank; Bethermin, Matthieu; Casey, Caitlin M.; Chen, Chian-Chou; Clements, David L.; Cicone, Claudia; Combes, Francoise; Conselice, Christopher; Cooray, Asantha; Coppin, Kristen; Daddi, Emanuele; Dannerbauer, Helmut; Dave, Romeel; Doherty, Matthew; Dunlop, James S.; Edge, Alastair; Farrah, Duncan; Franco, Maximilien; Fuller, Gary; Garratt, Tracy; Gear, Walter; Greve, Thomas R.; Hatziminaoglou, Evanthia; Hayward, Christopher C.; Ivison, Rob J.; Kawabe, Ryohei; Klaassen, Pamela; Knudsen, Kirsten K.; Kohno, Kotaro; Koprowski, Maciej; Lagos, Claudia D. P.; Magdis, Georgios E.; Magnelli, Benjamin; McGee, Sean L.; Michalowski, Michal; Mroczkowski, Tony; Noroozian, Omid; Oliver, Seb; Riechers, Dominik; Rujopakarn, Wiphu; Scott, Douglas; Serjeant, Stephen; Smith, Matthew W. L.; Swinbank, Mark; Tamura, Yoichi; Werf, Paul van der; Kampen, Eelco van; Verma, Aprajita; Vieira, Joaquin; Wagg, Jeff; Walter, Fabian; Wang, Lingyu; Wootten, Al; Yun, Min S. (2019-05-31)
      The Sloan Digital Sky Survey (SDSS) was revolutionary because of the extraordinary breadth and ambition of its optical imaging and spectroscopy. We argue that a 'sub-millimeter SDSS' - a sensitive large-area imaging+spectroscopic ...

    • Designing a space-based galaxy redshift survey to probe dark energy 

      Wang, Yun; Percival, Will; Cimatti, Andrea; Mukherjee, Pia; Guzzo, Luigi; Baugh, Carlton M.; Carbone, Carmelita; Franzetti, Paolo; Garilli, Bianca; Geach, James E.; Lacey, Cedric G.; Majerotto, Elisabetta; Orsi, Alvaro; Rosati, Piero; Samushia, Lado; Zamorani, Giovanni (2010-12)
      A space-based galaxy redshift survey would have enormous power in constraining dark energy and testing general relativity, provided that its parameters are suitably optimized. We study viable space-based galaxy redshift ...

    • Eigengalaxies: describing galaxy morphology using principal components in image space 

      Uzeirbegovic, Emir; Geach, James E.; Kaviraj, Sugata (2020-09-02)
      We demonstrate how galaxy morphologies can be represented by weighted sums of "eigengalaxies" and how eigengalaxies can be used in a probabilistic framework to enable principled and simplified approaches in a variety of ...

    • The Evolution of Dusty Star formation in Galaxy Clusters to z = 1 : Spitzer infrared Observations of the First Red-Sequence Cluster Survey 

      Webb, Tracy; O'Donnell, Daniel; K. C. Yee, Howard; Gilbank, David; Coppin, Kristen; Ellingson, Erica; Faloon, Ashley; Geach, James E.; Gladders, Mike; Noble, Allison; Muzzin, Adam; Wilson, Gillian; Yan, Renbin (2013)
      We present an IR study of high-redshift galaxy clusters with the MIPS camera on the Spitzer Space Telescope. Employing a sample of 42 clusters from the RCS-1 over the redshift range 0.3

    • Extending the Dynamic Range of Galaxy Outflow Scaling Relations: Massive Compact Galaxies with Extreme Outflows 

      Davis, Julie D.; Tremonti, Christy A.; Swiggum, Cameren N.; Moustakas, John; Diamond-Stanic, Aleksandar M.; Coil, Alison L.; Geach, James E.; Hickox, Ryan C.; Perrotta, Serena; Petter, Grayson C.; Rudnick, Gregory H.; Rupke, David S. N.; Sell, Paul H.; Whalen, Kelly E. (2023-07-06)
      We investigate galactic winds in the HizEA galaxies, a collection of 46 late-stage galaxy mergers at z = 0.4–0.8, with stellar masses of log(M*/M⊙)=10.4–11.5 , star formation rates (SFRs) of 20–500 M ⊙ yr−1, and ultra-compact ...

    • A flat trend of star-formation rate with X-ray luminosity of galaxies hosting AGN in the SCUBA-2 Cosmology Legacy Survey 

      Ramasawmy, Joanna; Stevens, Jason; Martin, Garreth; Geach, James E. (2019-07-01)
      Feedback processes from active galactic nuclei (AGN) are thought to play a crucial role in regulating star formation in massive galaxies. Previous studies using Herschel have resulted in conflicting conclusions as to whether ...

    • Galaxy morphological classification in deep-wide surveys via unsupervised machine learning 

      Martin, Garreth; Kaviraj, Sugata; Hocking, Alex; Read, Shaun C.; Geach, James E. (2019-10-26)
      Galaxy morphology is a fundamental quantity, that is essential not only for the full spectrum of galaxy-evolution studies, but also for a plethora of science in observational cosmology. While a rich literature exists on ...

    • Generative deep fields : arbitrarily sized, random synthetic astronomical images through deep learning 

      Smith, Michael J.; Geach, James E. (2019-10-21)
      Generative Adversarial Networks (GANs) are a class of artificial neural network that can produce realistic, but artificial, images that resemble those in a training set. In typical GAN architectures these images are small, ...

    • HiZELS: a high-redshift survey of H alpha emitters - I : The cosmic star formation rate and clustering at z=2.23 

      Geach, James E.; Smail, Ian; Best, P.N.; Kurk, J.; Casali, M.; Ivison, R. J.; Coppin, Kristen (2008-08-21)
      We present results from a near-infrared narrow-band survey of emission-line galaxies at z = 2.23, using the Wide Field Camera on the United Kingdom Infrared Telescope. The H(2)S1 narrow-band filter (lambda(c) = 2.121 mu ...

    • Host Dark Matter Halos of SDSS Red and Blue Quasars: No Significant Difference in Large-scale Environment 

      Petter, Grayson C.; Hickox, Ryan C.; Alexander, David M.; Geach, James E.; Myers, Adam D.; Rosario, David J.; Fawcett, Victoria A.; Klindt, Lizelke; Whalen, Kelly E. (2022-03-02)
      The observed optical colors of quasars are generally interpreted in one of two frameworks: unified models that attribute the color to the random orientation of the accretion disk along the line of sight, and evolutionary ...

    • Host Dark Matter Halos of Wide-field Infrared Survey Explorer-selected Obscured and Unobscured Quasars: Evidence for Evolution 

      Petter, Grayson C.; Hickox, Ryan C.; Alexander, David M.; Myers, Adam D.; Geach, James E.; Whalen, Kelly E.; Andonie, Carolina P. (2023-03-23)
      Obscuration in quasars may arise from steep viewing angles along the dusty torus, or instead may represent a distinct phase of supermassive black hole growth. We test these scenarios by probing the host dark matter halo ...

    • The Ionization and Dynamics of the Makani Galactic Wind 

      Rupke, David S. N.; Coil, Alison L.; Perrotta, Serena; Davis, Julie D.; Diamond-Stanic, Aleksandar M.; Geach, James E.; Hickox, Ryan C.; Moustakas, John; Petter, Grayson C.; Rudnick, Gregory H.; Sell, Paul H.; Tremonti, Christy A.; Whalen, Kelly E. (2023-04-18)
      The Makani galaxy hosts the poster child of a galactic wind on scales of the circumgalactic medium. It consists of a two-episode wind in which the slow, outer wind originated 400 Myr ago (Episode I; R I = 20 − 50 kpc) and ...

    • Kinematics, Structure, and Mass Outflow Rates of Extreme Starburst Galactic Outflows 

      Perrotta, Serena; Coil, Alison L.; Rupke, David S. N.; Tremonti, Christy A.; Davis, Julie D.; Diamond-Stanic, Aleksandar M.; Geach, James E.; Hickox, Ryan C.; Moustakas, John; Rudnick, Gregory H.; Sell, Paul H.; Swiggum, Cameren N.; Whalen, Kelly E. (2023-05-19)
      We present results on the properties of extreme gas outflows in massive (M * ∼ 1011 M ⊙), compact, starburst (star formation rate, SFR∼ 200 M ⊙ yr−1) galaxies at z = 0.4–0.7 with very high star formation surface densities ...

    • Observational constraints on the physical nature of submillimetre source multiplicity : chance projections are common 

      Hayward, Christopher C.; Chapman, Scott C.; Steidel, Charles C.; Golob, Anneya; Casey, Caitlin M.; Smith, Daniel J. B.; Zitrin, Adi; Blain, Andrew W.; Bremer, Malcolm N.; Chen, Chian-Chou; Coppin, Kristen E. K.; Farrah, Duncan; Ibar, Eduardo; Michałowski, Michał J.; Sawicki, Marcin; Scott, Douglas; Werf, Paul van der; Fazio, Giovanni G.; Geach, James E.; Gurwell, Mark; Petitpas, Glen; Wilner, David J. (2018-05-11)
      Interferometric observations have demonstrated that a significant fraction of single-dish submillimetre (submm) sources are blends of multiple submm galaxies (SMGs), but the nature of this multiplicity, i.e. whether the ...

    • On the evolution of the molecular gas fraction of star-forming galaxies 

      Geach, James E.; Smail, Ian; Moran, Sean M.; MacArthur, Lauren A.; Lagos, Claudia del P.; Edge, Alastair C. (2011-04)
      We present IRAM Plateau de Bure interferometric detections of CO (J = 1 -> 0) emission from a 24 mu m-selected sample of star-forming galaxies at z = 0.4. The galaxies have polycyclic aromatic hydrocarbon 7.7 mu m-derived ...

    • Physical Properties of Massive Compact Starburst Galaxies with Extreme Outflows 

      Perrotta, Serena; George, Erin R.; Coil, Alison L.; Tremonti, Christy A.; Rupke, David S. N.; Davis, Julie D.; Diamond-Stanic, Aleksandar M.; Geach, James E.; Hickox, Ryan C.; Moustakas, John; Petter, Grayson C.; Rudnick, Gregory H.; Sell, Paul H.; Swiggum, Cameren N.; Whalen, Kelly E. (2021-12-29)
      We present results on the nature of extreme ejective feedback episodes and the physical conditions of a population of massive (M * ∼ 1011 M ⊙), compact starburst galaxies at z = 0.4–0.7. We use data from Keck/NIRSPEC, SDSS, ...