141 research outputs found

    You Are What You Eat: The Circumgalactic Medium Around BreakBRD Galaxies has Low Mass and Angular Momentum

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    Observed breakBRD ("break bulges in red disks") galaxies are a nearby sample of face-on disk galaxies with particularly centrally-concentrated star formation: they have red disks but recent star formation in their centers as measured by the Dn_n4000 spectral index. In Kopenhafer et al. (2020), a comparable population of breakBRD analogues was identified in the TNG simulation, in which the central concentration of star formation was found to reflect a central concentration of dense, starforming gas caused by a lack of dense gas in the galaxy outskirts. In this paper we examine the circumgalactic medium of the central breakBRD analogues to determine if the extended halo gas also shows differences from that around comparison galaxies with comparable stellar mass. We examine the circumgalactic medium gas mass, specific angular momentum, and metallicity in these galaxy populations. We find less gas in the circumgalactic medium of breakBRD galaxies, and that the breakBRD circumgalactic medium is slightly more concentrated than that of comparable stellar mass galaxies. In addition, we find that the angular momentum in the circumgalactic medium of breakBRD galaxies tends to be low for their stellar mass, and show more misalignment to the angular momentum vector of the stellar disk. Finally, we find that the circumgalactic medium metallicity of breakBRD galaxies tends to be high for their stellar mass. Together with their low SFR, we argue that these CGM properties indicate a small amount of disk feeding concentrated in the central regions, and a lack of low-metallicity gas accretion from the intergalactic medium.Comment: Published in The Astrophysical Journal, July 202

    Refining the M_BH-V_c scaling relation with HI rotation curves of water megamaser galaxies

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    Black hole - galaxy scaling relations provide information about the coevolution of supermassive black holes and their host galaxies. We compare the black hole mass - circular velocity (MBH - Vc) relation with the black hole mass - bulge stellar velocity dispersion (MBH - sigma) relation, to see whether the scaling relations can passively emerge from a large number of mergers, or require a physical mechanism, such as feedback from an active nucleus. We present VLA H I observations of five galaxies, including three water megamaser galaxies, to measure the circular velocity. Using twenty-two galaxies with dynamical MBH measurements and Vc measurements extending to large radius, our best-fit MBH - Vc relation, log MBH = alpha + beta log(Vc /200 km s^-1), yields alpha = 7.43+/-0.13, beta = 3.68+1.23/-1.20, and intrinsic scatter epsilon_int = 0.51+0.11/-0.09. The intrinsic scatter may well be higher than 0.51, as we take great care to ascribe conservatively large observational errors. We find comparable scatter in the MBH - sigma relations, epsilon_int = 0.48+0.10/-0.08, while pure merging scenarios would likely result in a tighter scaling with the dark halo (as traced by Vc) than baryonic (sigma) properties. Instead, feedback from the active nucleus may act on bulge scales to tighten the MBH - sigma relation with respect to the MBH - Vc relation, as observed.Comment: 27 pages, 15 figures, ApJ accepte

    FIREBALL: Detector, data acquisition and reduction

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    The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009. The instrument combines microchannel plate detector technology with fiber-fed integral field spectroscopy on an unstable stratospheric balloon gondola platform. This unique combination poses a series of calibration and data reduction challenges that must be addressed and resolved to allow for accurate data analysis. We discuss our approach and some of the methods we are employing to accomplish this task
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