George M. Fuller, Alexander Kusenko, Volodymyr Takhistov

We show that some or all of the inventory of $r$-process nucleosynthesis can be produced in interactions of primordial black holes (PBHs) with neutron stars (NSs) if PBHs with masses ${10}^{-14}\,{\rm M}_\odot < {\rm M}_{\rm PBH} < {10}^{-8}\,{\rm M}_\odot$ make up a few percent or more of the dark matter. A PBH captured by a neutron star (NS) sinks to the center of the NS and consumes it from the inside. When this occurs in a rotating millisecond-period NS, the resulting spin-up ejects $\sim 0.1-0.5\,{\rm M}_{\odot}$ of relatively cold neutron-rich material. This ejection process and the accompanying decompression and decay of nuclear matter can produce electromagnetic transients, such as a kilonova-type afterglow and fast radio bursts. These transients are not accompanied by significant gravitational radiation or neutrinos, allowing such events to be differentiated from compact object mergers occurring within the distance sensitivity limits of gravitational wave observatories. The PBH-NS destruction scenario is consistent with pulsar and NS statistics, the dark matter content and spatial distributions in the Galaxy and Ultra Faint Dwarfs (UFD), as well as with the $r$-process content and evolution histories in these sites. Ejected matter is heated by beta decay, which leads to emission of positrons in an amount consistent with the observed 511-keV line from the Galactic Center.

Z. Hou, K. Aylor, B. A. Benson, L. E. Bleem, J. E. Carlstrom, C. L. Chang, H-M. Cho, R. Chown, T. M. Crawford, A. T. Crites, T. de Haan, M. A. Dobbs, W. B. Everett, B. Follin, E. M. George, N. W. Halverson, N. L. Harrington, G. P. Holder, W. L. Holzapfel, J. D. Hrubes, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch, D. Luong-Van, D. P. Marrone, J. J. McMahon, S. S. Meyer, M. Millea, L. M. Mocanu, J. J. Mohr, T. Natoli, Y. Omori, S. Padin, C. Pryke, C. L. Reichardt, J. E. Ruhl, J. T. Sayre, K. K. Schaffer, E. Shirokoff, Z. Staniszewski, A. A. Stark, K. T. Story, K. Vanderlinde, J. D. Vieira, R. Williamson

We study the consistency of 150 GHz data from the South Pole Telescope (SPT) and 143 GHz data from the \textit{Planck} satellite over the 2540 $\text{deg}^2$ patch of sky covered by the SPT-SZ survey. We first visually compare the maps and find that the map residuals appear consistent with noise after we account for differences in angular resolution and filtering. To make a more quantitative comparison, we calculate (1) the cross-spectrum between two independent halves of SPT 150 GHz data, (2) the cross-spectrum between two independent halves of \textit{Planck} 143 GHz data, and (3) the cross-spectrum between SPT 150 GHz and \textit{Planck} 143 GHz data. We find the three cross-spectra are well-fit (PTE = 0.30) by the null hypothesis in which both experiments have measured the same sky map up to a single free parameter characterizing the relative calibration between the two. As a by-product of this analysis, we improve the calibration of SPT data by nearly an order of magnitude, from 2.6\% to 0.3\% in power; the best-fit power calibration factor relative to the most recent published SPT calibration is $1.0174 \pm 0.0033$. Finally, we compare all three cross-spectra to the full-sky \textit{Planck} $143 \times 143$ power spectrum and find a hint ($\sim$1.5$\sigma$) for differences in the power spectrum of the SPT-SZ footprint and the full-sky power spectrum, which we model and fit as a power law in the spectrum. The best-fit value of this tilt is consistent between the three cross-spectra in the SPT-SZ footprint, implying that the source of this tilt---assuming it is real---is a sample variance fluctuation in the SPT-SZ region relative to the full sky. Despite the precision of our tests, we find no evidence for systematic errors in either data set. The consistency of cosmological parameters derived from these datasets is discussed in a companion paper.

Anne-Sylvie Deutsch

Coupling between sub- and super-Hubble modes can affect the locally observed statistics of our universe. In the context of Quasi-Single Field Inflation, we can compute correlation functions and derive the influence of those unobservable modes on observed correlation functions as well as on the inferred cosmological parameters. We study how different classes of diagrams affect the bispectrum in the squeezed limit; in particular, while contact-like diagrams leave the scaling between the long and short modes unchanged, exchange-like diagrams do modify the shape of the bispectrum. We show that the mass of the hidden sector field can hence be biased by an unavoidable cosmic variance that can reach a 1-$\sigma$ uncertainty of $\mathcal{O}(10\%)$ for a weakly non-Gaussian universe. Finally, we go beyond the bispectrum and show how couplings between unobservable and observable modes can affect generic correlation functions with arbitrary order non-derivative self-interactions.

Savvas M. Koushiappas, Abraham Loeb

We study the effects of black hole dark matter on the dynamical evolution of stars in dwarf galaxies. We find that mass segregation leads to a depletion of stars in the center of dwarf galaxies and the appearance of a ring in the projected stellar surface density profile. Using Segue 1 as an example we show that current observations of the projected surface stellar density rule out at the 99.9% confidence level the possibility that more than 4% of the dark matter is composed of black holes with a mass of few tens of solar masses.

Shu-Lei Cao, Huan-Yu Teng, Hao-Ran Yu, Hao-Yi Wan, Tong-Jie Zhang

In order to explore the generic properties of a backreaction model to explain the observations of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter is employed. However, we doubt that the evolving curvature parameter also obeys the scaling law, thus we make use of observational Hubble parameter data (OHD) to constrain parameters in dust cosmology to testify it. First, in FLRW model, after getting best-fit constraints of $\Omega^{{\mathcal{D}}_0}_m = 0.25^{+0.03}_{-0.03}$, $n = 0.02^{+0.69}_{-0.66}$, and $H_{\mathcal{D}_0} = 70.54^{+4.24}_{-3.97}\ {\rm km/s/Mpc}$, evolutions of parameters are studied. Second, in template metric context, by marginalizing over $H_{\mathcal{D}_0}$ as a prior of uniform distribution, we obtain the best-fit values as $n=-1.22^{+0.68}_{-0.41}$ and ${{\Omega}_{m}^{\mathcal{D}_{0}}}=0.12^{+0.04}_{-0.02}$. Moreover, we utilize three different Gaussian priors of $H_{\mathcal{D}_0}$, which result in different best-fits of $n$, but almost the same best-fit value of ${{\Omega}_{m}^{\mathcal{D}_{0}}}\sim0.12$. With these constraints, evolutions of the effective deceleration parameter $q^{\mathcal{D}}$ indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra dark energy component in the scaling solution context. However, the results also imply that the prescription of the geometrical instantaneous spatially-constant curvature $\kappa_{\mathcal{D}}$ of the template metric is insufficient and should be improved.