A Simple Technique for Predicting High-Redshift Galaxy Evolution

We show that the ratio of galaxies' specific star formation rates (SSFRs) to their host halos' specific mass accretion rates (SMARs) strongly constrains how the galaxies' stellar masses, specific star formation rates, and host halo masses evolve over cosmic time. This evolutionary constraint provides a simple way to probe z>8 galaxy populations without direct observations. Tests of the method with galaxy properties at z=4 successfully reproduce the known evolution of the stellar mass--halo mass (SMHM) relation, galaxy SSFRs, and the cosmic star formation rate (CSFR) for 5<z<8. We then predict the continued evolution of these properties for 8<z<15. In contrast to the non-evolution in the SMHM relation at z<4, the median galaxy mass at fixed halo mass increases strongly at z>4. We show that this result is closely linked to the flattening in galaxy SSFRs at z>2 compared to halo specific mass accretion rates; we expect that average galaxy SSFRs at fixed stellar mass will continue their mild evolution to z~15. The expected CSFR shows no breaks or features at z>8.5; this constrains both reionization and the possibility of a steep falloff in the CSFR at z=9-10. Finally, we make predictions for stellar mass and luminosity functions for the James Webb Space Telescope (JWST), which should be able to observe one galaxy with M* > ~10^8 Msun per 10^3 Mpc^3 at z=9.6 and one such galaxy per 10^4 Mpc^3 at z=15.Comment: Revised to include JWST luminosity functions, matching accepted versio

Recoiling Supermassive Black Hole Escape Velocities from Dark Matter Halos

We simulate recoiling black hole trajectories from $z=20$ to $z=0$ in dark matter halos, quantifying how parameter choices affect escape velocities. These choices include the strength of dynamical friction, the presence of stars and gas, the accelerating expansion of the universe (Hubble acceleration), host halo accretion and motion, and seed black hole mass. $\Lambda$CDM halo accretion increases escape velocities by up to 0.6 dex and significantly shortens return timescales compared to non-accreting cases. Other parameters change orbit damping rates but have subdominant effects on escape velocities; dynamical friction is weak at halo escape velocities, even for extreme parameter values. We present formulae for black hole escape velocities as a function of host halo mass and redshift. Finally, we discuss how these findings affect black hole mass assembly as well as minimum stellar and halo masses necessary to retain supermassive black holes.Comment: 10 pages, 17 figures. Updated to correct a typo (sign error) in fit to escape velocity, for return by z=0 (eq. 19

Dark Matter Disc Enhanced Neutrino Fluxes from the Sun and Earth

As disc galaxies form in a hierarchical cosmology, massive merging satellites are preferentially dragged towards the disc plane. The material accreted from these satellites forms a dark matter disc that contributes 0.25 - 1.5 times the non-rotating halo density at the solar position. Here, we show the importance of the dark disc for indirect dark matter detection in neutrino telescopes. Previous predictions of the neutrino flux from WIMP annihilation in the Earth and the Sun have assumed that Galactic dark matter is spherically distributed with a Gaussian velocity distribution, the standard halo model. Although the dark disc has a local density comparable to the dark halo, its higher phase space density at low velocities greatly enhances capture rates in the Sun and Earth. For typical dark disc properties, the resulting muon flux from the Earth is increased by three orders of magnitude over the SHM, while for the Sun the increase is an order of magnitude. This significantly increases the sensitivity of neutrino telescopes to fix or constrain parameters in WIMP models. The flux from the Earth is extremely sensitive to the detailed properties of the dark disc, while the flux from the Sun is more robust. The enhancement of the muon flux from the dark disc puts the search for WIMP annihilation in the Earth on the same level as the Sun for WIMP masses < 100 GeV.Comment: 7 pages, 4 figures, added a short paragraph to the discussion section, conclusions unchanged, published versio

Wakes in Dilatonic Current-Carrying Cosmic Strings

In this work, we present the gravitational field generated by a cosmic string carrying a timelike current in the scalar-tensor gravities. The mechanism of formation and evolution of wakes is fully investigated in this framework. We show explicitly that the inclusion of electromagnetic properties for the string induces logarithmic divergences in the accretion problem.Comment: Revised version to be published in the Phys. Rev.

Eigensinnige 'Kunden': Auswirkungen strenger Zumutbarkeitsregeln auf Langzeitarbeitslose und prekär Beschäftigte

Der Beitrag präsentiert erste Befunde aus dem Teilprojekt "Eigensinnige 'Kunden'. Die Auswirkungen strenger Zumutbarkeit auf die Erwerbsorientierung Arbeitsloser und prekär Beschäftigten" des SFB 580. Hauptsächlich auf eine qualitative Befragung von Beziehern des Arbeitslosengeldes II gestützt, argumentiert der Artikel vor dem Hintergrund der aktuellen underclass-Debatte. Er zeigt, dass es sich bei den Langzeitarbeitslosen keineswegs um Angehörige einer kulturell homogenen Unterschicht handelt. Ebenso wenig kann von einem breiten Verfall der Arbeitsmoral die Rede sein

TRINITY III: Quasar Luminosity Functions Decomposed by Halo, Galaxy, and Black Hole Masses and Eddington Ratios from z=0-10

We present the redshift evolution of quasar luminosity functions decomposed by halo mass, galaxy mass, supermassive black hole (SMBH) mass, and Eddington ratio, as well as SMBH kinetic/radiative energy output ratios from TRINITY, a flexible empirical model that self-consistently infers the halo--galaxy--SMBH connection that match observational data. Key findings include: 1) The normalization of QLF increases by ~3-4 dex from z~10 to z~4, due to the fast mass build-up of different SMBH populations; 2) From z~4 to z~1, less massive galaxies and SMBHs make up bigger and bigger fractions of QLFs, due to the AGN downsizing effect; 3) At z~0, massive haloes/galaxies/SMBHs are responsible for most bright quasars due to low Eddington ratios among all SMBHs; 4) The bright ends of quasar luminosity functions (QLFs) are dominated by SMBHs that are at least 0.3 dex over-massive relative to the median SMBH mass-galaxy mass relation; 5) QLFs at z~6-7 are dominated by SMBHs accreting at Eddington ratios 0.1 < $\eta_\mathrm{rad}$ < 1, but super-Eddington AGNs contribute more significantly to QLFs towards z~9-10.Comment: 18 pages, 14 figures. Accepted by MNRAS. Comments welcome

TRINITY II: The Luminosity-dependent Bias of the Supermassive Black Hole Mass--Galaxy Mass Relation for Bright Quasars at z=6z=6

Using recent empirical constraints on the dark matter halo--galaxy--supermassive black hole (SMBH) connection from $z=0-7$, we infer how undermassive, typical, and overmassive SMBHs contribute to the quasar luminosity function (QLF) at $z=6$. We find that beyond $L_\mathrm{bol} = 5 \times 10^{46}$ erg/s, the $z=6$ QLF is dominated by SMBHs that are at least 0.3 dex above the $z=6$ median $M_\bullet-M_*$ relation. The QLF is dominated by typical SMBHs (i.e., within $\pm 0.3$ dex around the $M_\bullet-M_*$ relation) at $L_\mathrm{bol} \lesssim 10^{45}$ erg/s. At $z\sim 6$, the intrinsic $M_\bullet-M_*$ relation for all SMBHs is slightly steeper than the $z=0$ scaling, with a similar normalization at $M_* \sim 10^{11} M_\odot$. We also predict the $M_\bullet-M_*$ relation for $z=6$ bright quasars selected by different bolometric luminosity thresholds, finding very good agreement with observations. For quasars with $L_\mathrm{bol} > 3 \times 10^{46}$ ($10^{48}$) erg/s, the scaling relation is shifted upwards by $\sim0.35$ (1.0) dex for $10^{11} M_\odot$ galaxies. To accurately measure the intrinsic $M_\bullet-M_*$ relation, it is essential to include fainter quasars with $L_\mathrm{bol} \lesssim 10^{45}$ erg/s. At high redshifts, low-luminosity quasars are thus the best targets for understanding typical formation paths for SMBHs in galaxies.Comment: 5 pages, 3 figures. Submitted to MNRAS Letters. Comments welcome

The Effects of X-Ray Feedback from AGN on Host Galaxy Evolution

Hydrodynamic simulations of galaxies with active galactic nuclei (AGN) have typically employed feedback that is purely local: i.e., an injection of energy to the immediate neighborhood of the black hole. We perform GADGET-2 simulations of massive elliptical galaxies with an additional feedback component: an observationally calibrated X-ray radiation field which emanates from the black hole and heats gas out to large radii from the galaxy center. We find that including the heating and radiation pressure associated with this X-ray flux in our simulations enhances the effects which are commonly reported from AGN feedback. This new feedback model is twice as effective as traditional feedback at suppressing star formation, produces 3 times less star formation in the last 6 Gyr, and modestly lowers the final BH mass (30%). It is also significantly more effective than an X-ray background in reducing the number of satellite galaxies.Comment: 9 emulateapj pages, 8 figures; accepted to Ap

Supervoid Origin of the Cold Spot in the Cosmic Microwave Background

We use a WISE-2MASS-Pan-STARRS1 galaxy catalog to search for a supervoid in the direction of the Cosmic Microwave Background Cold Spot. We obtain photometric redshifts using our multicolor data set to create a tomographic map of the galaxy distribution. The radial density profile centred on the Cold Spot shows a large low density region, extending over 10's of degrees. Motivated by previous Cosmic Microwave Background results, we test for underdensities within two angular radii, $5^\circ$, and $15^\circ$. Our data, combined with an earlier measurement by Granett et al 2010, are consistent with a large $R_{\rm void}=(192 \pm 15)h^{-1} Mpc$ $(2\sigma)$ supervoid with $\delta \simeq -0.13 \pm 0.03$ centered at $z=0.22\pm0.01$. Such a supervoid, constituting a $\sim3.5 \sigma$ fluctuation in the $\Lambda CDM$ model, is a plausible cause for the Cold Spot.Comment: 4 pages, 2 figures, Proceedings of IAU 306 Symposium: Statistical Challenges in 21st Century Cosmolog

Formation of early-type galaxies from cosmological initial conditions

We describe high resolution Smoothed Particle Hydrodynamics (SPH) simulations of three approximately $M_*$ field galaxies starting from \LCDM initial conditions. The simulations are made intentionally simple, and include photoionization, cooling of the intergalactic medium, and star formation but not feedback from AGN or supernovae. All of the galaxies undergo an initial burst of star formation at $z \approx 5$, accompanied by the formation of a bubble of heated gas. Two out of three galaxies show early-type properties at present whereas only one of them experienced a major merger. Heating from shocks and -PdV work dominates over cooling so that for most of the gas the temperature is an increasing function of time. By $z \approx 1$ a significant fraction of the final stellar mass is in place and the spectral energy distribution resembles those of observed massive red galaxies. The galaxies have grown from $z=1 \to 0$ on average by 25% in mass and in size by gas poor (dry) stellar mergers. By the present day, the simulated galaxies are old ($\approx 10 {\rm Gyrs}$), kinematically hot stellar systems surrounded by hot gaseous haloes. Stars dominate the mass of the galaxies up to $\approx 4$ effective radii ($\approx 10$ kpc). Kinematic and most photometric properties are in good agreement with those of observed elliptical galaxies. The galaxy with a major merger develops a counter-rotating core. Our simulations show that realistic intermediate mass giant elliptical galaxies with plausible formation histories can be formed from \LCDM initial conditions even without requiring recent major mergers or feedback from supernovae or AGN.Comment: accepted for publication in Ap