Black hole foraging: feedback drives feeding

We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy but little angular momentum to the surrounding gas. Once central accretion drops, the feedback weakens and swept-up gas falls back towards the SMBH on near-parabolic orbits. These intersect near the black hole with partially opposed specific angular momenta, causing further infall and ultimately the formation of a small-scale accretion disk. The feeding rates into the disk typically exceed Eddington by factors of a few, growing the hole on the Salpeter timescale and stimulating further feedback. Natural consequences of this picture include (i) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (ii) random orientations of successive accretion disk episodes; (iii) the possibility of rapid SMBH growth; (iv) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible flares and ejection of hypervelocity stars; (v) super-solar abundances of the matter accreting on to the SMBH; and (vi) a lower central dark-matter density, and hence annihilation signal, than adiabatic SMBH growth implies. We also suggest a simple sub-grid recipe for implementing this process in numerical simulations.Comment: accepted for publication in ApJ Letters, 5 pages, 1 figur

Misaligned gas discs around eccentric black-hole binaries and implications for the final-parsec problem

We investigate the evolution of low mass (Md /Mb = 0.005) misaligned gaseous discs around eccentric supermassive black hole (SMBH) binaries. These are expected to form from randomly oriented accretion events onto a SMBH binary formed in a galaxy merger. When expanding the interaction terms between the binary and a circular ring to quadrupole order and averaging over the binary orbit, we expect four non-precessing disc orientations: aligned or counter-aligned with the binary, or polar orbits around the binary eccentricity vector with either sense of rotation. All other orientations precess around either of these, with the polar precession dominating for high eccentricity. These expectations are borne out by smoothed particle hydrodynamics simulations of initially misaligned viscous circumbinary discs, resulting in the formation of polar rings around highly eccentric binaries in contrast to the co-planar discs around circular binaries. Moreover, we observe disc tearing and violent interactions between differentially precessing rings in the disc significantly disrupting the disc structure and causing gas to fall onto the binary with little angular momentum. While accretion from a polar disc may not promote SMBH binary coalescence (solving the `final-parsec problem'), ejection of this infalling low-angular momentum material via gravitational slingshot is a possible mechanism to reduce the binary separation. Moreover, this process acts on dynamical rather than viscous time scales, and so is much faster.Comment: 12 pages, 9 figures, Accepted for publication in MNRA

Early Stuart Courts Leet: Still Needful and Useful

Research of the past twenty years has corrected the view that post-medieval leets were decadent and has demonstrated that many Tudor leets remained active and powerful. This article attempts to demonstrate that several early Stuart leets were not "decadents", but still exercised jurisdiction over many misdemeanors and satisfied the desire and need for local, inexpensive, neighbourly justice. Given the local character of early Stuart society, and the dependence of justices upon inferior officers, courts leet were needful and useful.La recherche des vingt dernières années a modifié la vision traditionnelle selon laquelle les courts 1eet auraient sombré dans la décadence pendant la période moderne; elle a démontré que sous les Tudors, les courts 1eet étaient actives et puissantes. Cet article cherche à prouver que sous les Stuarts, un certain nombre de courts 1eet n'étaient pas décadentes, mais continuaient à exercer leur juridiction à l'encontre d'un grand nombre de délits et satisfaisaient le besoin pour une justice locale et peu coûteuse. Compte tenu de la décentralisation de l'Angleterre des Stuarts et de la dépendance des juges envers leurs subordonnés, les courts 1eet étaient nécéssaires et utiles

Letter from State\u27s Attorney King to Governor Langer regarding Edna Rehak vs International, 1938

The State\u27s Attorney, Walter C. King, is writing Governor William Langer about some confusion in the case Edna Rehak vs International Harvester Company. The State\u27s Attorney is unsure if the Rehak\u27s intend to move into town and discontinue farming. This is important because depending on what they intend to do, their machinery may or may not be protected under the farm moratorium. Due to this being rather important, State\u27s Attorney Walter C. King is recommending that Governor William Langer write Frank and Edna Rehak in order to learn of their intentions in references to their farm and equipment. See also Langer\u27s reply: Letter from Governor Langer to State\u27s Attorney King regarding Edna Rehak vs International 1938https://commons.und.edu/langer-papers/1094/thumbnail.jp