Browsing by Author "Nagar, Neil"

Now showing 1 - 6 of 6
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    ALMA Lensing Cluster Survey: average dust, gas, and star-formation properties of cluster and field galaxies from stacking analysis
    (2023) Guerrero, Andrea; Nagar, Neil; Kohno, Kotaro; Fujimoto, Seiji; Kokorev, Vasily; Brammer, Gabriel; Jolly, Jean-Baptiste; Knudsen, Kirsten; Sun, Fengwu; Bauer, Franz E.; Caminha, Gabriel B.; Caputi, Karina; Neumann, Gerald; Orellana-Gonzalez, Gustavo; Cerulo, Pierluigi; Gonzalez-Lopez, Jorge; Laporte, Nicolas; Koekemoer, Anton M.; Ao, Yiping; Espada, Daniel; Arancibia, Alejandra M. Munoz
    We develop new tools for continuum and spectral stacking of Atacama Large Millimeter/submillimeter Array (ALMA) data, and apply these to the ALMA Lensing Cluster Survey. We derive average dust masses, gas masses, and star-formation rates (SFRs) from the stacked observed 260-GHz continuum of 3402 individually undetected star-forming galaxies, of which 1450 are cluster galaxies and 1952 field galaxies, over three redshift and stellar mass bins (over z = 0-1.6 and log M-*[M-circle dot] = 8-11.7), and derive the average molecular gas content by stacking the emission line spectra in a SFR-selected subsample. The average SFRs and specific SFRs of both cluster and field galaxies are lower than those expected for main-sequence (MS) star-forming galaxies, and only galaxies with stellar mass of log M-*[M-circle dot] = 9.35-10.6 show dust and gas fractions comparable with those in the MS. The ALMA-traced average 'highly obscured' SFRs are typically lower than the SFRs observed from optical to near-infrared spectral analysis. Cluster and field galaxies show similar trends in their contents of dust and gas, even when field galaxies were brighter in the stacked maps. From spectral stacking we find a potential CO (J = 4 -> 3) line emission (signal-to-noise ratio being similar to 4) when stacking cluster and field galaxies with the highest SFRs.
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    How to fuel an AGN: mapping circumnuclear gas in NGC 6240 with ALMA
    (2019) Medling, Anne M.; Privon, George C.; Barcos Muñoz, Loreto; Treister, Ezequiel; Cicone, Claudia; Messias, Hugo; Sanders, David B.; Scoville, Nick Z.; U, Vivian; Bauer, Franz Erik; Armus, Lee; Chang, Chin-Shin; Comerford, Julia M.; Evans, Aaron S.; Max, Claire E.; Müller-Sánchez, Francisco; Nagar, Neil; Sheth, Kartik
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    Molecular Gas in Major Mergers Hosting Dual and Single AGNs at
    (2025) Johnstone, Makoto A.; Treister, Ezequiel; Bauer, Franz E.; Chin-Shin Chang; Cicone, Claudia; Koss, Michael J.; Del Moral Castro, Ignacio; Muller Sanchez, Francisco; Privon, George C.; Ricci, Claudio; Scoville, Nick; Venturi, Giacomo; Barcos Muñoz, Loreto; Armus, Lee; Blecha, Laura; Casey, Caitlin; Comerford, Julia; Evans, Aaron; Kawamuro, Taiki; Medling, Anne M.; Messias, Hugo; Nagar, Neil; Rojas, Alejandra; Sanders, David; Trakhtenbrot, Benny; U, Vivian; Urry, Meg
    We present high-resolution (∼50–100 pc) Atacama Large Millimeter/submillimeter Array observations of 12CO(2–1) or 12CO(1–0) emission in seven local (z ≲ 0.05) major mergers—five of which are dual active galactic nucleus (AGN) systems, and two of which are single AGN systems. We model the molecular gas kinematics through rotating disk profiles using a Bayesian Markov Chain Monte Carlo approach. The residuals were then used to isolate nonrotating components of the molecular gas—the most likely contributor to future supermassive black hole (SMBH) growth. We find that more-massive SMBHs have higher surface densities of nonrotating molecular gas within their sphere of influence. This potential molecular gas supply, however, does not correlate with the current accretion efficiency of the SMBHs, suggesting that only a fraction of the observed nonrotating gas is currently reaching the SMBH. Finally, we tentatively find no significant differences in the nuclear molecular gas masses of single-AGN and dual-AGN hosts, both within the SMBH sphere of influence and within the central kiloparsec. Our results indicate that the probability of occurrence of the dual AGN phenomenon is likely dependent on AGN variability and/or obscuration rather than the availability of molecular gas in the nuclear regions.
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    Optical, Near-IR, and Sub-mm IFU Observations of the Nearby Dual Active Galactic Nuclei MRK 463
    (2018) Treister, Ezequiel; Privon, George C.; Sartori, Lia F.; Nagar, Neil; Bauer, Franz Erik; Schawinski, Kevin; Messias, Hugo; Ricci, Claudio; U, Vivian; Casey, Caitlin M.; Comerford, Julia M.
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    Spatially Resolved Spectroscopy of Submillimeter Galaxies at z ≃ 2
    (2016) Olivares, V.; Treister, Ezequiel; Privon, George C.; Alaghband-Zadeh, S.; Casey, Caitlin M.; Schawinski, Kevin; Kurczynski, Peter; Gawiser, Eric.; Nagar, Neil; Chapman, S.; Bauer, Franz Erik
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    The Molecular Gas in the NGC 6240 Merging Galaxy System at the Highest Spatial Resolution
    (2020) Treister, Ezequiel; Messias, Hugo; Privon, George C.; Nagar, Neil; Medling, Anne M.; U, Vivian; Bauer, Franz Erik; Cicone, Claudia; Barcos Muñoz, Loreto; Venturi, Giacomo