Browsing by Author "Medling, Anne M."

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    Characterizing the Molecular Gas in Infrared Bright Galaxies with CARMA
    (2024) Alatalo, Katherine; Petric, Andreea O.; Lanz, Lauranne; Rowlands, Kate; Vivian, U.; Larson, Kirsten L.; Armus, Lee; Barcos-Munoz, Loreto; Evans, Aaron S.; Koda, Jin; Luo, Yuanze; Medling, Anne M.; Nyland, Kristina E.; Otter, Justin A.; Patil, Pallavi; Penaloza, Fernando; Salim, Diane; Sanders, David B.; Sazonova, Elizaveta; Skarbinski, Maya; Song, Yiqing; Treister, Ezequiel; Urry, C. Meg
    We present the CO(1-0) maps of 28 infrared-bright galaxies from the Great Observatories All-Sky Luminous Infrared Galaxy Survey (GOALS) taken with the Combined Array for Research in Millimeter Astronomy (CARMA). We detect 100 GHz continuum in 16 of the 28 CARMA GOALS galaxies, which trace both active galactic nuclei (AGNs) and compact star-forming cores. The GOALS galaxies show a variety of molecular gas morphologies, though in the majority of cases the average velocity fields show a gradient consistent with rotation. We fit the full continuum spectral energy distributions (SEDs) of each of the sources using either magphys or SED3FIT (if there are signs of an AGN) to derive the total stellar mass, dust mass, and SFRs of each object. We adopt a value determined from luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) of alpha CO = 1.5-0.8+1.3 M circle dot (K km s-1 pc2)-1, which leads to more physical values for f mol and the gas-to-dust ratio. Mergers tend to have the highest gas-to-dust ratios. We assume the cospatiality of the molecular gas and star formation and plot the CARMA GOALS sample on the Schmidt-Kennicutt relation, where we find that they preferentially lie above the line set by normal star-forming galaxies. This hyper-efficiency is likely due to the increased turbulence in these systems, which decreases the freefall time compared to star-forming galaxies, leading to "enhanced" star formation efficiency. Line wings are present in a non-negligible subsample (11/28) of the CARMA GOALS sources and are likely due to outflows driven by AGNs or star formation, gas inflows, or additional decoupled gas components.
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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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    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
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    Tracing the Ionization Structure of the Shocked Filaments of NGC 6240
    (2021) Medling, Anne M.; Kewley, Lisa J.; Calzetti, Daniela; Privon, George C.; Larson, Kirsten; Rich, Jeffrey A.; Armus, Lee; Allen, Mark G.; Bicknell, Geoffrey V.; Díaz-Santos, Tanio; Heckman, Timothy M.; Leitherer, Claus; Max, Claire E.; Rupke, David S. N.; Treister, Ezequiel; Messias, Hugo; Wagner, Alexander Y.
    We study the ionization and excitation structure of the interstellar medium in the late-stage gas-rich galaxy merger NGC 6240 using a suite of emission-line maps at similar to 25 pc resolution from the Hubble Space Telescope, Keck/NIRC2 with Adaptive Optics, and the Atacama Large Millimeter/submillimeter Array (ALMA). NGC 6240 hosts a superwind driven by intense star formation and/or one or both of two active nuclei; the outflows produce bubbles and filaments seen in shock tracers from warm molecular gas (H-2 2.12 mu m) to optical ionized gas ([O iii], [N ii], [S ii], and [O i]) and hot plasma (Fe XXV). In the most distinct bubble, we see a clear shock front traced by high [O iii]/H beta and [O iii]/[O i]. Cool molecular gas (CO(2-1)) is only present near the base of the bubble, toward the nuclei launching the outflow. We interpret the lack of molecular gas outside the bubble to mean that the shock front is not responsible for dissociating molecular gas, and conclude that the molecular clouds are partly shielded and either entrained briefly in the outflow, or left undisturbed while the hot wind flows around them. Elsewhere in the galaxy, shock-excited H-2 extends at least similar to 4 kpc from the nuclei, tracing molecular gas even warmer than that between the nuclei, where the two galaxies' interstellar media are colliding. A ridgeline of high [O iii]/H beta emission along the eastern arm aligns with the southern nucleus' stellar disk minor axis; optical integral field spectroscopy from WiFeS suggests this highly ionized gas is centered at systemic velocity and likely photoionized by direct line of sight to the southern active galactic nucleus.