Search

The physical trigger powering supernovae following the core collapse of massive stars is believed to involve a neutron star (NS) or a black hole (BH), depending largely on progenitor mass. A potentially distinct signature is a long-duration gravitational wave (GW) burst from BH central engines by their ample energy reservoir $E_J$ in angular momentum, far more so than an NS can provide. A natural catalyst for this radiation is surrounding high-density matter in the form of a non-axisymmetric disk or torus. Here, we derive a detailed outlook on LVK probes of core-collapse supernovae CC-SNe during the present observational run O4 based on their event rate, an association with normal long GRBs and mass-scaling of GW170817B/GRB170817A. For BH central engines of mass $M$, GW170817B predicts a descending GW-chirp of energy ${\cal E}_{GW}\simeq 3.5\% M_\odot c^2 \left(M/M_0\right)$ at frequency $f_{GW}\lesssim 700\,{\rm Hz}\left(M_0/M\right)$, where $M_0\simeq 2.8\,M_\odot$. For a few tens of events per year well into the Local Universe within 50-100Mpc, probes at the detector-limited sensitivity are expected to break the degeneracy between their NS or BH central engines {by GW calorimetry., Comment: 20 pages, 9 figures, to appear in ApJL

The mass-radius relationship of white dwarfs (WDs) is one of their defining characteristics, largely derived from electron degeneracy pressure. We present a model-independent study of the observed mass-radius relationship in WD binaries of \cite{Parsons_2017}, listing data over a broad temperature range up to about 60,000 K (5 eV). The data show an appreciable temperature sensitivity with pronounced intrinsic scatter (beyond measurement uncertainty) for the canonical He-models with proton-to-neutron ratio 1:1. We characterize temperature sensitivity by a temperature scale $T_0$ in model-agnostic power-law relations with temperature normalized radius. For low-mass WDs, the results identify a remarkably modest $T_0 = 1 \sim 2 $ eV. We comment on a potential interpretation for atmospheres insulating super-Eddington temperature cores from the sub-Eddington photospheres of low-mass WDs., Comment: 8 pages, 6 figures, to appear in NewA

Our cosmology contains Big Bang relic fluctuations by a loss of time-translation symmetry on a Hubble time scale. The contribution to the vacuum is identified with dynamical dark energy $\Lambda\simeq \alpha_p\Lambda_0$ by an IR coupling $\alpha_p\sim \hbar$ of the bare cosmological constant $\Lambda_0\sim\hbar^{-1}$ consistent with general relativity, where $\hbar$ is the Planck constant. Described by the trace $J=(1-q)H^2$ of the Schouten tensor derived from a path integral formulation with gauged global phase, the proposed $J$CDM takes us beyond the $\Lambda$CDM limit of frozen $J=\Lambda$. The Hubble constant $H_0$ in $J$CDM is effectively $\sqrt{6/5}$ times the {\em Planck} value in $\Lambda$CDM analysis of the CMB according to $H(z)=H_0\sqrt{1+(6/5)\Omega_{M,0} Z_5(z) + \Omega_{r,0}Z_6(z)}/(1+z)$, where $Z_n=(1+z)^n-1$ given densities of matter $\Omega_{M,0}$ and radiation $\Omega_{r,0}$. With no free parameters, $J$CDM hereby agrees with the Local Distance Ladder when satisfying the BAO measured by {\em Planck}. On this cosmological background, galaxies possess an essentially $C^0$-transition to anomalous dynamics due to reduced inertia below the de Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light. This is confirmed in SPARC over a 6$\sigma$ tension in $\Lambda$CDM galaxy models, pointing to ultra-light CDM of mass $m_Dc^2<3\times 10^{-21}$eV. Sensitivity to this cosmological background explains the JWST 'Impossible galaxies' at cosmic dawn by rapid gravitational collapse. We comment on an outlook on future confrontations with observations by {\em Euclid}., Comment: 29 pages, 6 figures, Invited talk at the Corfu2023 Workshop on Tensions in Cosmology

It is proposed that the baryonic Tully-Fisher relation (bTFR) and JWST 'Impossible galaxies' at cosmic dawn are unified in weak gravity by the trace $J$ of the Schouten tensor below the Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light and $H$ is the Hubble parameter. Across $a_{dS}$, $J$ parametrizes short-period galaxy rotation curves and fast gravitational collapse beyond the predictions of $\Lambda$CDM. The sensitivity of weak gravitation to $J=\frac{1}{6}R$ is derived in infrared gravitation from a consistent limit of quantum gravity, reducing to general relativity in the limit of a small Planck constant, where $R$ is Ricci scalar tensor. For the first time, it identifies the exact relation $a_0=c^2\sqrt{J}/2\pi$ of the Milgrom parameter across all redshifts, accounting for the bTFR and early galaxy formation accelerated by a factor $\sim J^{1/8}$. It predicts $a_0^\prime(0)<0$ at the present epoch., Comment: 8 pages

The Hubble expansion of the Universe is considered in the classical limit of Big Bang quantum cosmology. Consistency with general relativity obtains in an IR coupling to the bare cosmological constant parameterized by the Hubble horizon. The resulting effective dark energy $\Lambda$ has a simple meaning as a relic of the Big Bang, breaking time-translation invariance on a Hubble time-scale. We identify $\Lambda$ with the trace $J$ of the Schouten tensor, allowing for an analytic solution $H(z)$ beyond $\Lambda$CDM. Subject to the {\em Baryonic Accoustic Oscillations} (BAO), $J$CDM predicts $H_0$ to be $\sqrt{6/5}$ times $H_0$ in $\Lambda$CDM. $J$CDM is consistent with the $\Lambda$CDM fit to the {\em Planck} 2018 power spectrum of the CMB, while alleviating the $H_0$-tension with the Local Distance Ladder., Comment: Extended version of talk at 32nd Texas Symp. Rel. Astroph., Shanghai, Session 7 (2023); updated with a fit to the Planck 2018 power spectrum of the CMB

Searches for signals at low signal-to-noise ratios frequently involve the Fast Fourier Transform (FFT). For high-throughput searches, we here consider FFT on the homogeneous mesh of Processing Elements (PEs) of a wafer-scale engine (WSE). To minimize memory overhead in the inherently non-local FFT algorithm, we introduce a new synchronous slide operation ({\em Slide}) exploiting the fast interconnect between adjacent PEs. Feasibility of compute-limited performance is demonstrated in linear scaling of Slide execution times with varying array size in preliminary benchmarks on the CS-2 WSE. The proposed implementation appears opportune to accelerate and open the full discovery potential of FFT-based signal processing in multi-messenger astronomy., Comment: 7 pages, 6 figures

Recent JWST surveys reveal a striking abundance of massive galaxies at cosmic dawn, earlier than predicted by $\Lambda$CDM. The implied speed-up in galaxy formation by gravitational collapse is reminiscent of short-period galaxy dynamics described by the baryonic Tully-Fisher relation. This may originate in weak gravitation tracking the de Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light and $H(z)\propto \left(1+z\right)^{3/2}$ is the Hubble parameter with redshift $z$. With no free parameters, this produces a speed-up in early galaxy formation by an order of magnitude with essentially no change in initial galaxy mass function. It predicts a deceleration parameter $q_0=1-\left( 2\pi/GAa_{dS}\right)^2 = -0.98\pm 0.5$, where $G$ is Newton's constant and $A=(47\pm6)M_\odot$\,(km/s)$^{-4}$ is the baryonic Tully-Fisher coefficient (McGaugh 2012). At $3\sigma$ significance, it identifies dynamical dark energy alleviating $H_0$-tension when combined with independent $q_0$ estimates in the Local Distance Ladder. Conclusive determination of $q_0=d\log(\theta(z)H(z))/dz\left|_{z=0}\right.$ is expected from BAO angle $\theta(z)$ observations by the recently launched {\em Euclid} mission., Comment: To appear in Physics of the Dark Universe, 8 pages, 2 figures

Black holes evolve by evaporation of their event horizon. While this process is believed to be unitary, there is no consensus on the recovery of information in black hole entropy. A missing link is a unit of information in black hole evaporation. Distinct from Hawking radiation, we identify evaporation in entangled pairs by $\mathbb{P}^2$ topology of the event horizon consistent with the Bekenstein-Hawking entropy in a uniformly spaced horizon area, where $k_B$ denotes the Boltzmann constant. It derives by continuation of $\mathbb{P}^2$ in Rindler spacetime prior to gravitational collapse, subject to a tight correlation of the fundamental frequency of Quasi-Normal-Mode (QNM) ringing in gravitational and electromagnetic radiation. Information extraction from entangled pairs by detecting one over the surface spanned by three faces of a large cube carries a unit of information of $2\log3$ upon including measurement of spin., Comment: 5 pages, 2 figures, updated from KPS 70th Anniversary and 2022 Fall Meeting, Busan, South Korea, Oct 19-21, 2022 (Session Field and String Theory, Part B2.01)

The double neutron star (DNS) merger event GW170817 signifies the first multimessenger (MM) event with electromagnetic-gravitational (EM-GW) observations. LIGO-Virgo-KAGRA observational runs O4-5 promise to detect similar events and as yet unknown GW signals, which require confirmation in two or more detectors with comparable performance. To this end, we quantify duty cycles of comparable science quality of data in coincident H1L1-observations, further to seek consistent event rates of astrophysical transients in upcoming EM-GW surveys. Quite generally, discovery power scales with exposure time, sensitivity, and critically depends on the percentage of time when detectors operate at high quality. We quantify coincident duty cycles over a time-frequency domain $W\times B$, defined by segments of duration $W=8$s, motivated by a long-duration descending GW-chirp during GRB170817A, and the minimum detector noise over about $B=100-250\,$Hz. This detector yield factor satisfies $1\%-25 \%$ in S5-6 and O1-O3ab, significantly different from duty cycles of H1 and L1 individually with commensurable impact on consistency in event rates in EM-GW surveys. Significant gain in discovery power for signals whose frequency varies slowly in time may be derived from improving detector yield factors by deploying time-symmetric data analysis methods. For O4-5, these can yield improvements by factors up to $\mathcal{O}(10^5)$ relative to existing data and methods. Furthermore, the diversity of MM afterglows to DNS mergers may be greatest for systems similar to GW170817 but possibly less so for systems of substantially different mass such as GW190425. We summarize our findings with an outlook on EM-GW surveys during O4-5 and perspectives for next-generation GRB missions like THESEUS., Comment: 30 pages, 12+1 figures

The central engine of GRB170817A post-merger to GW170817 is probed by GW-calorimetry and event timing, applied to a post-merger descending chirp which can potentially break the degeneracy in spin-down of a neutron star or black hole remnant by the relatively large energy reservoir in the angular momentum, $E_J$, of the latter according to the Kerr metric. This analysis derives from model-agnostic spectrograms with equal sensitivity to ascending and descending chirps generated by time-symmetric butterfly matched filtering. The sensitivity was calibrated by response curves generated by software injection experiments. The statistical significance for candidate emission from the central engine of GRB170817A is expressed by probabilities of false alarm (PFA; type I errors) derived from an event-timing analysis. PDFs were derived for start-time $t_s$, identified via high-resolution image analyses of the available spectrograms. For merged (H1,L1)-spectrograms of the LIGO detectors, a PFA $p_1$ derives from causality in $t_s$ given GW170817-GRB17081A. A statistically independent confirmation is presented in individual H1 and L1 analyses, in a second PFA $p_2$ of consistency in their respective observations of $t_s$. A combined PFA derives from their product since mean and (respectively) difference in timing are statistically independent. Applied to GW170817-GRB170817A, PFAs of event timing in $t_s$ produce $p_1=8.3\times 10^{-4}$ and $p_2=4.9\times 10^{-5}$ of a post-merger output ${\cal E}_{GW}\simeq 3.5\%M_\odot c^2$ ($p_1p_2=4.1\times 10^{-8}$, equivalent $Z$-score 5.48). ${\cal E}_{GW}$ exceeds $E_J$ of the hyper-massive neutron star in the immediate aftermath of GW170817, yet it is consistent with $E_J$ rejuvenated in delayed gravitational collapse to a Kerr black hole. Similar emission may be expected from energetic core-collapse supernovae producing black holes. (Abbr.), Comment: A&A (in press); 17 pages, 6 figures, 4 appendices

The distribution of LIGO black hole binaries (BBH) shows an intermediate-mass range consistent with the Salpeter Initial Mass Function (IMF) in black hole formation by core-collapse supernovae, subject to preserving binary association. They are effectively parameterized by mean mass $\mu$ with Pearson correlation coefficient $r = 0.93\,\pm\,0.06$ of secondary to primary masses with mean mass-ratio $\bar{q}\simeq 0.67$, $q=M_2/M_1$, consistent with the paucity of intermediate-mass X-ray binaries. The mass-function of LIGO BBHs is well-approximated by a broken power-law with a tail $\mu\gtrsim 31.4M_\odot$ {in the mean binary mass $\mu=\left(M_1+M_2\right)/2$}. Its power-law index $\alpha_{B,true}=4.77\pm 0.73$ inferred from the tail of the observed mass-function is found to approach the upper bound $2\alpha_S=4.7$ of the uncorrelated binary initial mass-function, defined by the Salpeter index $\alpha_S=2.35$ of the Initial Mass Function of stars. The observed low scatter in BBH mass ratio $q$ evidences equalizing mass-transfer in binary evolution prior to BBH formation. At the progenitor redshift $z^\prime$, furthermore, the power-law index satisfies $\alpha_B^\prime>\alpha_B$ in a flat $\Lambda$CDM background cosmology. The bound $\alpha_{B,true}^\prime \lesssim 2\alpha_S$ hereby precludes early formation at arbitrarily high redshift $z^\prime \gg1$, that may be made more precise and robust with extended BBH surveys from upcoming LIGO O4-5 observations., Comment: 7 pages, 6 figures

Unparticle cosmology gives an unconventional outlook on the dark sector of cosmology, increasingly challenging $\Lambda\mbox{CDM}$ by $H_0$-tension. This model derives from a finite temperature broken conformal symmetry of radiation, described by a non-radiative correction with unknown sign in energy density. This symmetry breaking has a sign ambiguity, in which corrections about the IR fixed point are normal or tachyonic. While the first has been ruled out in a recent study, the latter possesses a late-time temperature $T_c\simeq 4\,T_{CMB}$ associated with $\Omega_{\cal U}\simeq 1$ ($\Omega_{\cal U} \simeq 10^4 \Omega_{CMB}$), where $T_{CMB}$ denotes the temperature of the Cosmic Microwave Background (CMB). Thus exposed to the enormous heat bath of unparticles, $T_{CMB}$ is constrained by the astronomical age of the Universe $T_{u,0}$. The relative temperature shift $\Delta T/T$ in any heat exchange to the CMB is hereby limited to the uncertainty of a few percent in $T_{u,0}$. This bounds the effective cross-section of unparticles interactions with CMB photons to $\sigma _{\gamma \mathcal{U}} \lesssim 10^{-40}\ \mbox{m}^2=10^{-3}\ \mbox{nb}$. Assuming a standard cross-section across the broadband mass and energy spectrum of unparticles, a more stringent bound $\sigma _{\gamma \mathcal{U}} \lesssim 10^{-3}\,\mbox{pb}$ derives from COBE-FIRAS constraints on spectral distortions. The first is midway of photon-neutrino $\sigma_{\gamma\nu}$ and photon-photon cross sections $\sigma_{\gamma\gamma}$, the second is on par with $\sigma_{\gamma\nu}$. These constraints put late-time unparticle cosmology, if present, at the edge of the standard model., Comment: 22 pages, 1 figure

The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and space-born instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA's first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed; ultracompact stellar-mass binaries, massive black hole binaries, and extreme or intermediate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help making progress in the different areas. New research avenues that LISA itself, or its joint exploitation with upcoming studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe.

Multi-messenger astrophysics is becoming a major avenue to explore the Universe, with the potential to span a vast range of redshifts. The growing synergies between different probes is opening new frontiers, which promise profound insights into several aspects of fundamental physics and cosmology. In this context, THESEUS will play a central role during the 2030s in detecting and localizing the electromagnetic counterparts of gravitational wave and neutrino sources that the unprecedented sensitivity of next generation detectors will discover at much higher rates than the present. Here, we review the most important target signals from multi-messenger sources that THESEUS will be able to detect and characterize, discussing detection rate expectations and scientific impact., Comment: Submitted to Experimental Astronomy

GW170817/GRB170817A probably marks a double neutron star coalescence. Extended Emission $t_s\simeq (0.67\pm0.03)$\,s post-merger shows an estimated energy output ${\cal E}\simeq (3.5\pm1)\%M_\odot c^2$ determined by response curves to power-law signal injections, where $c$ is the velocity of light. It provides calorimetric evidence for a rotating black hole of $\sim 3M_\odot$, inheriting the angular momentum $J$ of the merged hyper-massive neutron star in the immediate aftermath of GW170817 following core-collapse about or prior to $t_s$. Core collapse greatly increases the central energy reservoir to $E_J\lesssim 1M_\odot c^2$, accounting for ${\cal E}$ even at modest efficiencies in radiating gravitational waves through a non axisymmetric thick torus. The associated multi-messenger output in ultra-relativistic outflows and sub-relativistic mass-ejecta is consistent with observational constraints from the GRB-afterglow emission of GRB170817A and accompanying kilonova., Comment: 6 p., 5 fig

On the largest scales, planetary climates can be described by their Rossby number (\textit{Ro}). \textit{Ro} is in response to $Gr/Re^2$ , where Gr is the Grashof number and Re is the Reynolds number. We here simplify $Gr/Re^2$ as h, where $h=H/H_{Earth}$ with $H=gP/(2\pi V_e)$ for a planet with surface gravity \textit{g}, rotation period \textit{P} and equatorial velocity V\textsubscript{e}. Unlike \textit{h}, \textit{Ro} is difficult to obtain because of a large diversity in observation. We perform on an in-depth literature search on average (av) and maximum (mx) wind velocity for each planet in the Solar system by various observational methods and by altitude. We explore a correlation between \textit{Ro} and \textit{h} expressed as a power law with index $\alpha$ based on wind velocities of planets in the Solar system. We obtain a correlation between \textit{Ro} and \textit{h} with $\alpha=0.56$ (av) and $\alpha=0.52$ (mx). Earth's $H=H_{Earth}$ ($h=1$) is primarily due to lunar tidal interaction, given our relatively distant habitable zone (HZ) to the Sun. Our positive correlation, therefore, suggests exoplanet-moon systems as the `go-to-place' in our searches for potentially advanced life in exosolar system., Comment: 2 figs

We here revisit the essential problem of dynamical stability of planetary orbits around stellar binaries. We build on the coplanar three-body system of the Dvorak(1986), extending his stability diagram to both corotation and counter rotation of P-type orbits. His stability diagram express the change of stability across the gap between upper(UCO) and lower(LCO) critical orbits. By radius, this gap has a width of about 8$\%$ in the corotation case and 24$\%$ in the counter rotation case. As the gap of the second lies below the first, counter rotation is more stable, yet by width it is more chaotic. The gap between UCO and LCO follows a transition radius $r^+_g = 2.39 + 2.53e - 1.40 e^2$ and $r^-_g = 0.92 - 2.47e$ for corotation and respectively, counter rotation of the third body (the planet). Our $r^+_g$ agrees with the same of Dvorak to within 0.35$\%$. As a result, we discover $r^+_g/r^-_g \lesssim 2.57$ for all $e$. Around dim binaries, therefore, a relatively close in habitable zone may still be populated with planets on counter rotating orbits. The accurate numerical results presented here based on adaptive integration using MATLAB ODE45 may also serve as a novel benchmark of accurate \textit{N}-body integrators of exosolar systems more generally.

Realising de Sitter vacua in string theory is challenging. For this reason it has been conjectured that de Sitter vacua inhabit the Swampland of inconsistent low-energy effective theories coupled to gravity. Since de Sitter is an attractor for $\Lambda$CDM, the conjecture calls $\Lambda$CDM into question. Reality appears sympathetic to this idea as local measurements of the Hubble constant $H_0$ are also at odds with $\Lambda$CDM analysis of Planck data. This tension suggests that the de Sitter state is unstable, thereby implying a turning point in the Hubble parameter. We present a model relieving this tension, which predicts a turning at small positive redshift $z_*$ that is dictated by present-day matter density $\omega_m$. This feature is easily identified by homogeneous surveys covering redshifts $z \leq 0.1$. We comment on the implications for the Swampland program., Comment: v1 4 pages, comments welcome; v2 replacing mistakenly uploaded unfinished version; v3 arguments revised; v4; v5 matches published version, further changes outcome of the review process

The recent LIGO event GW170817 is the merger of a double neutron star system with an associated short GRB170817A with $2.9\pm0.3$\,s soft emission over 8-70\,keV. This association has a Gaussian equivalent level of confidence of 5.1$\sigma$. The merger produced a hyper-massive neutron star of stellar mass black hole with prompt or continuous energy output powering GRB170817A. {Here, we report on a possible detection of} Extended Emission (EE) in gravitational radiation {\em during} GRB170817A: a descending chirp with characteristic time scale $\tau_s=3.01\pm0.2\,$s in a (H1,L1)-spectrogram up to 700\,Hz with {Gaussian equivalent level of confidence greater than 3.3$\sigma$ based on causality alone following edge detection applied to (H1,L1)-spectrograms merged by frequency coincidences. Additional confidence derives from the strength of this EE.} The observed frequencies below 1kHz indicate a hyper-massive magnetar rather than a black hole, spinning down by magnetic winds and interactions with dynamical mass ejecta., Comment: talk at KAGRA f2f, Osaka (May 20 2018); Revised following an invited telecon seminar to LIGO-Virgo (July 25 2018); invited talk SIGRAV 2018, Italy; MNRAS Lett., to appear

Radial accelerations $\alpha$ in galaxy dynamics are now observed over an extended range in redshift that includes model calculations on galactic distributions of cold dark matter (CDM) in $\Lambda$CDM. In a compilation of data of the {\em Spitzer} Photometry and Accurate Rotation Curves (SPARC) catalogue, the recent sample of Genzel et al.(2017) and the McMaster Unbiased Galaxy Simulations 2, we report on effective self-similarity in the variable $\zeta = a_N/a_{dS}$, given by the Newtonian acceleration $a_N$ based on baryonic matter content over the de Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light and $H$ is the Hubble parameter. SPARC, MUG2 and theory satisfy ${a_N}/{\alpha} \simeq 2.1\,\zeta^\frac{1}{2}$ $(\zeta <<1)$. At $\zeta=1$ in transition to Newtonian gravity ($\zeta>>1$), however, there is a $6\sigma$ gap between SPARC and MUGS2. This poses a novel challenge to CDM in $\Lambda$CDM against the apparent $C^0$ galaxy dynamics observed in SPARC. We attribute the latter to reduced inertia below the de Sitter scale of acceleration $(\zeta < 1)$, based on a causality constraint imposed by the cosmological horizon ${\cal H}$., Comment: published version (4 pages, 3 figures) of APS April 2018 talk, Session K13

High-frequency multi-messenger observations provide a powerful probe of gamma-ray bursts (GRBs), pioneered by {\em BeppoSAX} in gamma-rays and LIGO-Virgo in gravitational waves. Identifying the central engines - magnetars or black holes - also promises to improve on GRBs as probes of cosmological evolution. THESEUS' design is ideally suited to pursue both science objectives. Here, we present a general-purpose {\em graphics processor units} (GPU)-accelerated broadband search algorithm for long duration ascending and descending chirps, post-merger or from core-collapse of massive stars, in electromagnetic and gravitational radiation. It implements butterfly filtering using banks of up to 8 million templates of 1 second duration at over one million correlations per second by heterogeneous computing using a dozen high-end GPUs. We demonstrate its application with the identification of broadband Kolmogorov spectra in long GRBs and the long duration ascending chirp in the merger GW170817. The first shows a noticeable absence of a high frequency bump, otherwise expected from newly formed magnetar central engines. The second illustrates the need for deep searches to identify GRB central engines in descending chirps in gravitational waves, post-merger or from nearby energetic core-collapse supernovae. A future catalogue of THESEUS' GRBs covering a broad range of redshifts may probe the nature of the cosmological vacuum and establish the de Sitter limit as a turning point in cosmological evolution., Comment: To be published in the Proceedings of the THESEUS Workshop 2017 (http://www.isdc.unige.ch/theseus/workshop2017.html), Journal of the Italian Astronomical Society (Mem.SAIt), Editors L. Amati, E. Bozzo, M. Della Valle, D. Gotz, P. O'Brien. Details on the THESEUS mission concept can be found in the white paper Amati et al. 2017 (arXiv:171004638) and Stratta et al. 2017 (arXiv:1712.08153)

Multi-messenger emissions from SN1987A and GW170817/GRB170817A suggest a Universe rife with multi-messenger transients associated with black holes and neutron stars. For LIGO-Virgo, soon to be joined by KAGRA, these observations promise unprecedented opportunities to probe the central engines of core-collapse supernovae (CC-SNe) and gamma-ray bursts. Compared to neutron stars, central engines powered by black hole-disk or torus systems may be of particular interest to multi-messenger observations by the relatively large energy reservoir $E_J$ of angular momentum, up to 29\% of total mass in the Kerr metric. These central engines are expected from relatively massive stellar progenitors and compact binary coalescence involving a neutron star. We review prospects of multi-messenger emission by catalytic conversion of $E_J$ by a non-axisymmetric disk or torus. Observational support for this radiation process is found in a recent identification of ${\cal E}\simeq (3.5\pm1)\%M_\odot c^2$ in Extended Emission to GW170817 at a significance of 4.2\,$\sigma$ concurrent with GRB170817A. A prospect on similar emissions from nearby CC-SNe justifies the need for all-sky blind searches of long duration bursts by heterogeneous computing., Comment: 96 pages, 20 figures

Galaxy dynamics probes weak gravity at accelerations below the de Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light and $H$ is the Hubble parameter. Low and high redshift galaxies hereby offer a novel probe of weak gravity in an evolving cosmology, satisfying $H(z)=H_0\sqrt{1+\omega_m(6z+12z^2+12z^3+6z^4+(6/5)z^5)}/(1+z)$ with baryonic matter content $\omega_m$ sans tension to $H_0$ in surveys of the Local Universe. Galaxy rotation curves show anomalous galaxy dynamics in weak gravity $a_N

We present a heterogeneous search algorithm for broadband extended gravitational-wave emission (BEGE), expected from gamma-ray bursts and energetic core-collapse supernovae. It searches the $(f,\dot{f})$-plane for long duration bursts by inner engines slowly exhausting their energy reservoir by matched filtering on a {\em Graphics Processor Unit} (GPU) over a template bank of millions of one-second duration chirps. Parseval's Theorem is used to predict the standard deviation $\sigma$ of filter output, taking advantage of near-Gaussian noise in LIGO S6 data over 350-2000 Hz. Tails exceeding a mulitple of $\sigma$ are communicated back to a {\em Central Processing Unit} (CPU). This algorithm attains about 65\% efficiency overall, normalized to the Fast Fourier Transform (FFT). At about one million correlations per second over data segments of 16 s duration $(N=2^{16}$ samples), better than real-time analysis is achieved on a cluster of about a dozen GPUs. We demonstrate its application to the capture of high frequency hardware LIGO injections. This algorithm serves as a starting point for deep all-sky searches in both archive data and real-time analysis in current observational runs., Comment: to appear in Progress of Theoretical and Experimental Physics (PTEP), 16p., 9 fig

The $H_0$-tension problem poses a confrontation of dark energy driving late-time cosmological expansion measured by the Hubble parameter $H(z)$ over an extended range of redshifts $z$. Distinct values $H_0\simeq 73$ km\,s$^{-1}$Mpc$^{-1}$ and $H_0\simeq 68$ km\,s$^{-1}$Mpc$^{-1}$ obtain from surveys of the Local Universe and, respectively, $\Lambda$CBM analysis of the CMB. These are representative of accelerated expansion with $H^\prime(0)\simeq0$ by $\Lambda=\omega_0^2$ and, respectively, $H^\prime(0)>0$ in $\Lambda$CDM, where $\omega_0=\sqrt{1-q}H$ is a fundamental frequency of the cosmological horizon in a Friedmann-Robertson-Walker universe with deceleration parameter $q(z)=-1+(1+z)H^{-1}H^\prime(z)$. Explicit solutions $H(z)=H_0\sqrt{1+\omega_m(6z+12z^2+12z^3+6z^4+(6/5)z^5)}$ and, respectively, $H(z)=H_0\sqrt{1-\omega_m+\omega_m(1+z)^3}$ are here compared with recent data on $H(z)$ over $0\lesssim z \lesssim2$. The first is found to be free of tension with $H_0$ from local surveys, while the latter is disfavored at $2.7\sigma$. A further confrontation obtains in galaxy dynamics by a finite sensitivity of inertia to background cosmology in weak gravity, putting an upper bound of $m\lesssim 10^{-30}$eV on the mass of dark matter. A $C^0$ onset to weak gravity at the de Sitter scale of acceleration $a_{dS}=cH(z)$, where $c$ denotes the velocity of light, can be seen in galaxy rotation curves covering $0\lesssim z \lesssim 2$. Weak gravity in galaxy dynamics hereby provides a proxy for cosmological evolution., Comment: Invited talk, Joint Conference of ICGAC-XIII and IK15, July 3-7, Seoul (revised with additional discussion on weak gravity)

We present a theory of weak gravity parameterized by a fundamental frequency $\omega_0 = \sqrt{1-q}H$ of the cosmoloogical horizon, where $H$ and $q$ denote the Hubble and, respectively, deceleration parameter. It predicts (i) a $C^0$ onset to weak gravity across accelerations $\alpha = a_{dS}$ in galaxy rotation curves, where $a_{dS}=cH$ denotes the de Sitter acceleration with velocity of light $c$, and (ii) fast evolution $Q(z)=dq(z)/dz$ of the deceleration parameter by $\Lambda=\omega_0^2$ satisfying $Q_0>2.5$, $Q_0=Q(0)$, distinct from $Q_0\lesssim1$ in $\Lambda$CDM. The first is identified in high resolution data of Lellie et al.(2017), the second in heterogeneous data on $H(z)$ over $0

We consider weak gravity at accelerations $\alpha2.5$) versus $\Lambda$CDM ($Q_0<1$)., Comment: 13 pages, 2 figures, Invited Physics Seminar, Dept. Physics, UWA, Perth (October 17 2016); KPS Fall Meeting 2016; Invited talk at 7th KIAS Conf. Cosmology and Structure Formation (Oct. 30 - Nov. 4 2016)

The Groningen gas field shows exponential growth in earthquakes event counts around a magnitude M1 with a doubling time of 6-9 years since 2001. This behavior is identified with dimensionless curvature in land subsidence, which has been evolving at a constant rate over the last few decades {essentially uncorrelated to gas production.} We demonstrate our mechanism by a tabletop crack formation experiment. The observed skewed distribution of event magnitudes is matched by that of maxima of event clusters with a normal distribution. It predicts about one event $<$\,M5 per day in 2025, pointing to increasing stress to human living conditions., Comment: 12 pages, 7 figures, to appear in Earthquakes and Structures

The super-luminous object ASASSN-15lh (SN2015L) is an extreme event with a total energy $E_{rad}\simeq 1.1\times 10^{52}$ erg in black body radiation on par with its kinetic energy $E_k$ in ejecta and a late time plateau in the UV, that defies a nuclear origin. It likely presents a new explosion mechanism for hydrogen-deprived supernovae. With no radio emission and no H-rich environment we propose to identify $E_{rad}$ with dissipation of a baryon-poor outflow in the optically thick remnant stellar envelope produced by a central engine. By negligible time scales of light crossing and radiative cooling of the envelope, SN2015L's light curve closely tracks the evolution of this engine. We here model its light curve by the evolution of black hole spin, during angular momentum loss in Alv\'en waves to matter at the Inner Most Stable Circular Orbit (ISCO). The duration is determined by $\sigma=M_T/M$ of the torus mass $M_T$ around the black hole of mass $M$: $\sigma\sim 10^{-7}$ and $\sigma\sim 10^{-2}$ for SN2015L and, respectively, a long GRB. The observed electromagnetic radiation herein represents a minor output of the rotational energy $E_{rot}$ of the black hole, while most is radiated unseen in gravitational radiation. This model explains the high-mass slow-spin binary progenitor of GWB150914, as the remnant of two CC-SNe in an intra-day binary of two massive stars. This model rigorously predicts a change in magnitude $\Delta m\simeq 1.15$ in the light curve post-peak, in agreement with the light curve of SN2015L with no fine-tuning., Comment: MNRAS, published online, doi: 10.1093/mnras/stw2496

The Moon migrated to $r_{\leftmoon}\simeq3.8\times10^{10}$ cm over a characteristic time $r/v=10^{10}$ Gyr by tidal interaction with the Earth's oceans at a present velocity of $v=3.8$ cm yr$^{-1}$. We derive scaling of global dissipation that covers the entire history over the past 4.52 Gyr. Off-resonance tidal interactions at relatively short tidal periods in the past reveal the need for scaling {with amplitude}. The global properties of the complex spatio-temporal dynamics and dissipation in broad spectrum ocean waves is modeled by damping $\epsilon = h F/(2Q_0)$, where $h$ is the tidal wave amplitude, $F$ is the tidal frequency, and $Q_0$ is the $Q$-factor at the present time. It satisfies $Q_0\simeq 14$ for consistency of migration time and age of the Moon consistent with observations for a near-resonance state today. It shows a startingly fast eviction of the Moon from an unstable near-synchronous orbit close to the Roche limit, probably in a protolunar disk. Rapid spin down of the Earth from an intial $\sim30\%$ of break-up by the Moon favored early formation of a clement global climate. Our theory suggests moons may be similarly advantageous to potentially habitable exoplanets., Comment: 8 pages, 5 figures

(Short abstract). In Galilean physics, the universality of free fall implies an inertial frame, which in turns implies that the mass m of the falling body is omitted. Otherwise, an additional acceleration proportional to m/M would rise either for an observer at the centre of mass of the system, or for an observer at a fixed distance from the centre of mass of M. These elementary, but overlooked, considerations fully respect the equivalence principle and the identity of an inertial or a gravitational pull for an observer in the Einstein cabin. They value as fore-runners of the self-force and gauge dependency in general relativity. The approximate nature of Galilei's law of free fall is explored herein. When stepping into general relativity, we report how the geodesic free fall into a black hole was the subject of an intense debate again centred on coordinate choice. Later, we describe how the infalling mass and the emitted gravitational radiation affect the free fall motion of a body. The general relativistic self-force might be dealt with to perfectly fit into a geodesic conception of motion. Then, embracing quantum mechanics, real black holes are not classical static objects any longer. Free fall has to handle the Hawking radiation, and leads us to new perspectives on the varying mass of the evaporating black hole and on the varying energy of the falling mass. Along the paper, we also estimate our findings for ordinary masses being dropped from a Galilean or Einsteinian Pisa-like tower with respect to the current state of the art drawn from precise measurements in ground and space laboratories, and to the constraints posed by quantum measurements. The appendix describes how education physics and high impact factor journals discuss the free fall. Finally, case studies conducted on undergraduate students and teachers are reviewed.

The nature of dark energy may be probed by the derivative $Q=\left.dq(z)/dz\right|_0$ at redshift $z=0$ of the deceleration parameter $q(z)$. It is probably static if $Q<1$ or dynamic if $Q>2.5$, supporting $\Lambda$CDM or, respectively, $\Lambda=(1-q)H^2$, where $H$ denotes the Hubble parameter. We derive $q=1-\left(4\pi a_0/cH\right)^{2}$, enabling a determination of $q(z)$ by measurement of Milgrom's parameter $a_0(z)$ in galaxy rotation curves, equivalent to the coefficient $A$ in the Tully-Fisher relation $V^4_c=AM_b$ between rotation velocity $V_c$ and baryonic mass $M_b$. We infer that dark matter should be extremely light with clustering limited to the size of galaxy clusters. The associated transition radius to non-Newtonian gravity may conceivably be probed in a free fall Cavendish type experiment in space., Comment: to appear in ApJ

Core-collapse supernovae are factories of neutron stars and stellar mass black holes. Type Ib/c supernovae stand out as potentially originating in relatively compact stellar binaries and their branching ratio of about 1\% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein accretion of fall-back matter down to the Inner Most Stable Circular Orbit (ISCO) offers a window to {\em broadband extended gravitational-wave emission} (BEGE). To search for BEGE, we introduce a butterfly filter in time-frequency space by Time Sliced Matched Filtering. To analyze long epochs of data, we propose using coarse grained searches followed by high resolution searches on events of interest. We illustrate our proposed coarse grained search on two weeks of LIGO S6 data prior to SN 2010br $(z=0.002339)$ using a bank of up to 64 thousand templates of one second duration covering a broad range in chirp frequencies and bandwidth. Correlating events with signal-to-noise ratios $>6$ from the LIGO L1 and H1 detectors each reduces to a few events of interest. Lacking any further properties reflecting a common excitation by broadband gravitational radiation, we disregarded these as spurious. This new pipeline may be used to systematically search for long duration chirps in nearby core-collapse supernovae from robotic optical transient surveys using embarrassingly parallel computing., Comment: 26 pages, 8 figures, to appear in ApJ

Long gamma-ray bursts (GRBs) associated with supernovae and short GRBs with Extended Emission (SGRBEE) from mergers are probably powered by black holes as a common inner engine, as their prompt GRB emission satisfies the same Amati correlation in the $E_{p,i}-E_{iso}$ plane. We introduce modified Bardeen equations to identify hyper-accretion driving newly formed black holes in core-collapse supernovae to near-extremal spin as a precursor to prompt GRB emission. Subsequent spin-down is observed in the BATSE catalog of long GRBs. Spin-down provides a natural unification of long durations associated with the lifetime of black hole spin for normal long GRBs and SGRBEEs, given the absence of major fallback matter in mergers. The results point to major emissions unseen in high frequency gravitational waves. A novel matched filtering method is described for LIGO-Virgo and KAGRA broadband probes of nearby core-collapse supernovae at essentially maximal sensitivity.

Gravitational wave bursts in the formation of neutron stars and black holes in energetic core-collapse supernovae (CC-SNe) are of potential interest to LIGO-Virgo and KAGRA. Events nearby are readily discovered using moderately sized telescopes. CC-SNe are competitive with mergers of neutron stars and black holes, if the fraction producing an energetic output in gravitational waves exceeds about 1\%. This opportunity motivates the design of a novel Sejong University Core-CollapsE Supernova Survey (SUCCESS), to provide triggers for follow-up searches for gravitational waves. It is based on the 76 cm Sejong University Telescope (SUT) for weekly monitoring of nearby star-forming galaxies, i.e., M51, M81-M82 and Blue Dwarf Galaxies from the Unified Nearby Galaxy Catalog with an expected yield of a few hundred per year. Optical light curves will be resolved for the true time-of-onset for probes of gravitational waves by broadband time-sliced matched filtering.

Black holes in core-collapse of massive stars are expected to surge in mass and angular momentum by hyper-accretion immediately following their formation. We here describe a general framework of extended emission in gravitational waves from non-axisymmetric accretion flows from fallback matter of the progenitor envelope. It shows (a) a maximum efficiency in conversion of accretion energy into gravitational waves at hyper-accretion rates exceeding a critical value set by the ratio of the quadrupole mass inhomogeneity and viscosity with (b) a peak characteristic strain amplitude at the frequency $f_b=\Omega_b/\pi$, where $\Omega_b$ is the Keplerian angular velocity at which viscous torques equal angular momentum loss in gravitational radiation, with $h_{char}\propto f^{1/6}$ at $ff_b$. Upcoming gravitational wave observations may probe this scaling by extracting broadband spectra using time-sliced matched filtering with chirp templates, recently developed for identifying turbulence in noisy time series., Comment: to appear in ApJ

Black hole space times evaporate in discrete steps due to remarkably slow Hawking radiation. We here identify evaporation with essentially extremal states at the limit of quantum computation, performing $2.7\times 10^{79}$ bit calculations per photon emission in a one solar mass black hole. During evaporation, particles in free fall co-evolve satisfying $EM=$constant, where $E$ and $M$ denote the total mass energy-at-infinity of the particle and, respectively, black hole. Particles are hereby increasingly entangled with the black hole space-time over the course of its evaporation., Comment: 4 pages, 1 figure; revision following presentation at the KIAS-CFHEP and 5th KIAS Worskhop on Particle Physics and Cosmology, November 10 2015

It is shown that holographic cosmology implies an evolving Hubble radius $c^{-1}\dot{R}_H = -1 + 3\Omega_m$ in the presence of a dimensionless matter density $\Omega_m$ scaled to the closure density $3H^2/8\pi G$, where $c$ denotes the velocity of light and $H$ and $G$ denote the Hubble parameter and Newton's constant. It reveals a dynamical dark energy and a sixfold increase in gravitational attraction to matter on the scale of the Hubble acceleration. It reproduces the transition redshift $z_t\simeq 0.4$ to the present epoch of accelerated expansion and is consistent with $(q_0,(dq/dz)_0)$ of the deceleration parameter $q(z)=q_0+(dq/dz)_0z$ observed in Type Ia supernovae., Comment: 5 pages, 2 figures

Extreme sources in the Transient Universe show evidence of relativistic outflows from intermittent inner engines, such as cosmological gamma-ray bursts. They probably derive from rotating back holes interacting with surrounding matter. We show that these interactions are enhanced inversely proportional to the duty cycle in advection of magnetic flux, as may apply at high accretion rates. We demonstrate the morphology and ballistic propagation of relativistic ejecta from burst outflows by numerical simulations in relativistic magnetohydrodynamics. Applied to stellar mass black holes in core-collapse of massive stars, it provides a robust explosion mechanism as a function of total energy output. At breakout, these ejecta may produce a low-luminosity GRB. A long GRB may ensue from an additional ultra-relativistic baryon-poor inner jet from a sufficiently long-lived intermittent inner engine. The simulations demonstrate a complex geometry in mergers of successive ejecta, whose mixing and shocks provide a pathway to broadband high energy emission from magnetic reconnection and shocks., Comment: MNRASL, to appear

Broad band power density spectra offer a window to understanding turbulent behavior in the emission mechanism and, at the highest frequencies, in the putative inner engines powering long GRBs. We describe a chirp search method which steps aside Fourier analysis for signal detection in the Poisson noise-dominated 2 kHz sampled BeppoSAX light curves. An efficient numerical implementation is described in $O(Nn\log n)$ operations, where $N$ is the number of chirp templates and $n$ is the length of the light curve time series, suited for embarrassingly parallel processing. For detection of individual chirps of duration $\tau=1$ s, the method is one order of magnitude more sensitive in SNR than Fourier analysis. The Fourier-chirp spectra of GRB 010408 and GRB 970816 show a continuation of the spectral slope up to 1 kHz of turbulence identified in low frequency Fourier analysis. The same continuation is observed in an ensemble averaged spectrum of 40 bright long GRBs. An outlook on a similar analysis of upcoming gravitational wave data is included.

The Burst and Transient Source Experiment (BATSE) classifies cosmological gamma-ray bursts (GRBs) into short (less than 2 s) and long (over 2 s) events, commonly attributed to mergers of compact objects and, respectively, peculiar core-collapse supernovae. This standard classification has recently been challenged by the {\em Swift} discovery of short GRBs showing Extended Emission (SGRBEE) and nearby long GRBs without an accompanying supernova (LGRBN). Both show an initial hard pulse, characteristic of SGRBs, followed by a long duration soft tail. We here consider the spectral peak energy ($E_{p,i}$)-radiated energy $(E_{iso})$ correlation and the redshift distributions to probe the astronomical and physical origin of these different classes of GRBs. We consider {\em Swift} events of $15$ SGRBs, $7$ SGRBEEs, 3 LGRBNs and 230 LGRBs. The spectral-energy properties of the initial pulse of both SGRBEE and LGRBNs are found to coincide with those of SGRBs. A Monte Carlo simulation shows that the redshift distributions of SGRBs, SGRBEE and LGRBNs fall outside the distribution of LGRBs at 4.75$\,\sigma$, 4.67$\,\sigma$ and 4.31$\sigma$, respectively. A distinct origin of SGRBEEs with respect to LGRBs is also supported by the elliptical host galaxies of the SGRBEE events 050509B and 050724. This combined evidence supports the hypothesis that SGRBEE and LGRBNs originate in mergers as SGRBs. Moreover, long/soft tail of SGRB and LGRBNs satisfy the same $E_{p,i}-E_{iso}$ Amati-correlation holding for normal LGRBs. This fact points to rapidly rotating black holes as a common long-lived inner engine produced by different astronomical progenitors (mergers and supernovae).

Dark energy inferred from the observed negative deceleration parameter introduces a small mass of the graviton, that satisfies the Higuchi stability condition. It implies an infra-red modification of gravitation that produces Milgrom's inverse distance law of gravitational attraction in excellent agreement with the observed galaxy rotation curves. We conclude that dark matter is present cosmologically with no need for local clustering in galaxies., Comment: minor revision of introduction; 3 pages, 1 figure, presented at the 4th KIAS Workshop on Particle Physics and Cosmology, Oct 27-31, Seoul

Event counts are a powerful diagnostic for earthquake analysis. We report on a bimodal distribution of earthquake event counts in the U.S. since 2013. The new peak is about a magnitude M1 with a distribution very similar to that of induced earthquakes in Groningen, The Netherlands, characterized by exponential growth in event count since 2001. The latter shows a doubling time of 6.24 years with a relatively constant rate of land subsidence. We model its internal shear stresses as a function of dimensionless curvature and illustrate the resulting exponential growth in a tabletop crack formation experiment. Our study proposes a new method of parameter-free statistical forecasting of induced events, that circumvents the need for a magnitude cut-off in the Gutenberg-Richter relationship.