Browsing by Author "Simmons, Brooke D."
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- ItemChandra Observations of Galaxy Zoo Mergers : Frequency of Binary Active Nuclei in Massive Mergers.(2012) Teng, Stacy H.; Treister, Ezequiel; Schawinski, Kevin; Urry, C. Meg; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; Simmons, Brooke D.
- ItemDo Moderate-Luminosity Active Galactic Nuclei Suppress Star Formation?(2009) Schawinski, Kevin; Treister, Ezequiel; Virani, Shanil; Simmons, Brooke D.; Urry, C. Megan; Kaviraj, Sugata; Kushkuley, Bronika
- ItemEvidence for Three Accreting Black Holes in a Galaxy at z ~ 1.35: A Snapshot of Recently Formed Black Hole Seeds?(2011) Schawinski, Kevin; Treister, Ezequiel; Urry, C. Meg; Simmons, Brooke D.; Natarajan, Priyamvada; Glikman, Eilat
- ItemHeavily obscured quasar host galaxies at z ∼ 2 are discs, not major mergers.(2012) Schawinski, Kevin; Treister, Ezequiel; Simmons, Brooke D.; Urry, C. Meg; Glikman, Eilat
- ItemMajor Galaxy Mergers Only Trigger the Most Luminous Active Galactic Nuclei.(2012) Treister, Ezequiel; Schawinski, Kevin; Urry, C. Meg; Simmons, Brooke D.
- ItemObscured GOODS Active Galactic Nuclei and Their Host Galaxies at z < 1.25 : The Slow Black Hole Growth Phase.(2011) Simmons, Brooke D.; Treister, Ezequiel; Van Duyne, J.; Urry, C. Meg; Koekemoer, A. M.; Grogin, N. A.
- ItemSignatures of feedback in the spectacular extended emission region of NGC 5972(2023) Harvey, Thomas; Maksym, W. Peter; Keel, William; Koss, Michael; Bennert, Vardha N.; Chojnowski, S. Drew; Treister, Ezequiel; Finlez, Carolina; Lintott, Chris J.; Moiseev, Alexei; Simmons, Brooke D.; Sartori, Lia F.; Urry, MeganWe present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 ‘Voorwerpjes’ galaxies. This galaxy contains an extended emission-line region (EELR) and an arcsecond scale nuclear bubble. NGC 5972 is a faded active galactic nucleus (AGN), with EELR luminosity suggesting a 2.1 dex decrease in Lbol in the last ∼5 × 104 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broad-band (0.3–8 keV) X-ray emission in the near-nuclear regions, coincident with the [O III] bubble, as well as diffuse soft X-ray emission coincident with the EELR. The soft nuclear (0.5–1.5 keV) emission is spatially extended and the spectra are consistent with two APEC thermal populations (∼0.80 and ∼0.10 keV). We find a bubble age >2.2 Myr, suggesting formation before the current variability. We find evidence for efficient feedback with Pkin/Lbol ∼ 0.8 per cent, which may be overestimated given the recent Lbol variation. [O III] kinematics show a 300 km s−1 high-ionization velocity consistent with disturbed rotation or potentially the line-of-sight component of a ∼780 km s−1 thermal X-ray outflow capable of driving strong shocks to photoionize the precursor material. We explore possibilities to explain the overall jet, radio lobe and EELR misalignment including evidence for a double supermassive black hole which could support a complex misaligned system.
- ItemThe green valley is a red herring : Galaxy Zoo reveals two evolutionary pathways towards quenching of star formation in early- and late-type galaxies.(2014) Schawinski, Kevin; Treister, Ezequiel; Urry, C. Megan; Simmons, Brooke D.; Fortson, Lucy; Kaviraj, Sugata; Keel, William C.; Lintott, Chris J.; Masters, K. L.; Nichol, Robert C.; Sarzi, Marc