August 2021 (Page 2)

First Frequency-Time-Resolved Imaging Spectroscopy Observations of Solar Radio Spikes. (arXiv:2108.06191v2 [astro-ph.SR] CROSS LISTED) <a href="http://arxiv.org/find/astro-ph/1/au:+Clarkson_D/0/1/0/all/0/1">Daniel L. Clarkson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kontar_E/0/1/0/all/0/1">Eduard P. Kontar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gordovskyy_M/0/1/0/all/0/1">Mykola Gordovskyy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chrysaphi_N/0/1/0/all/0/1">Nicolina Chrysaphi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vilmer_N/0/1/0/all/0/1">Nicole Vilmer</a> Solar radio spikes are short duration and narrow bandwidth fine structures in dynamic spectra observed from GHz to tens of MHz range. Their very short duration and narrow frequency bandwidth are indicative of sub-second small-scale energy release in the solar corona, yet their origin is not understood. Using the LOw Frequency ARray (LOFAR), we present spatially, frequency and time resolved observations of individual radio spikes associated with a coronal mass ejection (CME). Individual radio spikeRead More →

A Search for Satellite Galaxies of Nearby Star-Forming Galaxies with Resolved Stars in LBT-SONG. (arXiv:2105.01082v2 [astro-ph.GA] CROSS LISTED) <a href="http://arxiv.org/find/astro-ph/1/au:+Garling_C/0/1/0/all/0/1">Christopher T. Garling</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peter_A/0/1/0/all/0/1">Annika H. G. Peter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kochanek_C/0/1/0/all/0/1">Christopher S. Kochanek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sand_D/0/1/0/all/0/1">David J. Sand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crnojevic_D/0/1/0/all/0/1">Denija Crnojevi&#x107;</a> We present results from a resolved stellar population search for dwarf satellite galaxies of six nearby (D $<5$ Mpc), sub-Milky-Way mass hosts using deep ($msim27$ mag) optical imaging from the Large Binocular Telescope. We perform image simulations to quantify our detection efficiency for dwarfs over a large range in luminosity and size, and develop a fast catalog-based emulator that includes a treatment of unresolved photometric blending. WeRead More →

XMP gas-rich dwarfs in nearby voids: results of BTA spectroscopy. (arXiv:2108.12065v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Pustilnik_S/0/1/0/all/0/1">S. A. Pustilnik</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Egorova_E/0/1/0/all/0/1">E. S. Egorova</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Kniazev_A/0/1/0/all/0/1">A. Y. Kniazev</a> (3,4,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Perepelitsyna_Y/0/1/0/all/0/1">Y. A. Perepelitsyna</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Tepliakova_A/0/1/0/all/0/1">A. L. Tepliakova</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Burenkov_A/0/1/0/all/0/1">A.N. Burenkov</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Oparin_D/0/1/0/all/0/1">D. V. Oparin</a> (1) ((1) Special Astrophysical Observatory of RAS, Russia, (2) Sternberg Astronomical Institute of Moscow State University, Russia, (3) South African Astronomical Observatory, Cape Town, South Africa, (4) Southern African Large Telescope Foundation, Cape Town, South Africa) We present the second part of results of the on-going project of searching for and studying eXtremely Metal-Poor (XMP, adopted as those withRead More →

Neutron Star Persistent Shift Phenomena and Relavant Data Fitting Analysis. (arXiv:2108.10508v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_C/0/1/0/all/0/1">Chun Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_C/0/1/0/all/0/1">Chenwei Lin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xie_J/0/1/0/all/0/1">Jiachen Xie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_X/0/1/0/all/0/1">Xiaoping Zheng</a> Pulsar glitches are the sudden increase in their spin frequency, most accompanied with a long timescale recovery process. A permanent shift would be remained in the first order derivative of spin frequency with time. Relevant data fitting research about this persistent shift was performed in this essay, we have found a more suitable fitting strategy by choosing a fitting function form $kln(ax + b)$ and demonstrated that would be more meaningful in pure mathematical aspect in describe the correlation betweenRead More →

From Warm Planets to Perpendicular Hot Planets. (arXiv:2108.09325v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Dawson_R/0/1/0/all/0/1">Rebekah I. Dawson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrecht_S/0/1/0/all/0/1">Simon H. Albrecht</a> High eccentricity tidal migration (HEM) is a promising channel for the origins of hot Jupiters and hot Neptunes. In the typical HEM scenario, a planet forms beyond the ice line, but alternatively a planet can disk migrate or form warm and undergo a short final stretch of HEM. At the warm origin point, general relavistic precession can reduce the amplitude of Kozai-Lidov oscillations driven by an outer companion. We show that warm planets that achieve HEM under these conditions — and with common types of planetary andRead More →

IIB String Theory and Sequestered Inflation. (arXiv:2108.08492v2 [hep-th] UPDATED) <a href="http://arxiv.org/find/hep-th/1/au:+Kallosh_R/0/1/0/all/0/1">Renata Kallosh</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Linde_A/0/1/0/all/0/1">Andrei Linde</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Wrase_T/0/1/0/all/0/1">Timm Wrase</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Yamada_Y/0/1/0/all/0/1">Yusuke Yamada</a> We develop sequestered inflation models, where inflation occurs along flat directions in supergravity models derived from type IIB string theory. It is compactified on a ${mathbb{T}^6 over mathbb{Z}_2 times mathbb{Z}_2}$ orientifold with generalized fluxes and O3/O7-planes. At Step I, we use flux potentials which 1) satisfy tadpole cancellation conditions and 2) have supersymmetric Minkowski vacua with flat direction(s). The 7 moduli are split into heavy and massless Goldstone multiplets. At Step II we add a nilpotent multiplet and uplift the flat direction(s) of theRead More →

Sequestered Inflation. (arXiv:2108.08491v2 [hep-th] UPDATED) <a href="http://arxiv.org/find/hep-th/1/au:+Kallosh_R/0/1/0/all/0/1">Renata Kallosh</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Linde_A/0/1/0/all/0/1">Andrei Linde</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Wrase_T/0/1/0/all/0/1">Timm Wrase</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Yamada_Y/0/1/0/all/0/1">Yusuke Yamada</a> We construct supergravity models allowing to sequester the phenomenology of inflation from the Planckian energy scale physics. The procedure consists of two steps: At Step I we study supergravity models, which might be associated with string theory or M-theory, and have supersymmetric Minkowski vacua with flat directions. At Step II we uplift these flat directions to inflationary plateau potentials. We find certain conditions which ensure that the superheavy fields involved in the stabilization of the Minkowski vacua at Step I are completely decoupled from the inflationary phenomenology. WeRead More →

Searching for Kardashev Type III civilisations from High $q$-Value Sources in the LoTSS-DR1 Value-added Catalogue. (arXiv:2108.06597v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_H/0/1/0/all/0/1">Hong-Ying Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garrett_M/0/1/0/all/0/1">Michael Garrett</a> Kardashev Type III civilisations have by definition energy requirements that are likely to generate strong excess emission in the mid-infrared (MIR) that is associated with the waste heat they generate. For those civilisations that capture starlight via Dyson sphere like constructions, the Optical to MIR flux ratio of the host galaxies is also expected to be unusually low. Since a wide range of galaxy types adhere to the infrared-radio correlation (IRC), galaxies hosting Type III civilisations should also strongly deviate fromRead More →

Timing observations of three Galactic millisecond pulsars. (arXiv:2108.03946v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Lorimer_D/0/1/0/all/0/1">D.R. Lorimer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawash_A/0/1/0/all/0/1">A.M. Kawash</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Freire_P/0/1/0/all/0/1">P.C.C. Freire</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_D/0/1/0/all/0/1">D.A. Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kerr_M/0/1/0/all/0/1">M. Kerr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McLaughlin_M/0/1/0/all/0/1">M.A. McLaughlin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mickaliger_M/0/1/0/all/0/1">M.B. Mickaliger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spiewak_R/0/1/0/all/0/1">R. Spiewak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bailes_M/0/1/0/all/0/1">M. Bailes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barr_E/0/1/0/all/0/1">E. Barr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burgay_M/0/1/0/all/0/1">M. Burgay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cameron_A/0/1/0/all/0/1">A.D. Cameron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Camilo_F/0/1/0/all/0/1">F. Camilo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnston_S/0/1/0/all/0/1">S. Johnston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jankowski_F/0/1/0/all/0/1">F. Jankowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Keane_E/0/1/0/all/0/1">E.F. Keane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Keith_M/0/1/0/all/0/1">M. Keith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kramer_M/0/1/0/all/0/1">M. Kramer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Possenti_A/0/1/0/all/0/1">A. Possenti</a> We report observed and derived timing parameters for three millisecond pulsars (MSPs) from observations collected with the Parkes 64-m telescope, Murriyang. The pulsars were found during re-processing of archival survey data by Mickaliger et al. One of theRead More →

New limits on the Lorentz/CPT symmetry through fifty gravitational-wave events. (arXiv:2108.02974v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Wang_Z/0/1/0/all/0/1">Ziming Wang</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Shao_L/0/1/0/all/0/1">Lijing Shao</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Liu_C/0/1/0/all/0/1">Chang Liu</a> Lorentz invariance plays a fundamental role in modern physics. However, tiny violations of the Lorentz invariance may arise in some candidate quantum gravity theories. Prominent signatures of the gravitational Lorentz invariance violation (gLIV) include anisotropy, dispersion, and birefringence in the dispersion relation of gravitational waves (GWs). Using a total of 50 GW events in the GW transient catalogs GWTC-1 and GWTC-2, we perform an analysis on the anisotropic birefringence phenomenon. The use of multiple events allows us to completely break the degeneracy amongRead More →

Analyticity and Unitarity for Cosmological Correlators. (arXiv:2108.01695v2 [hep-th] UPDATED) <a href="http://arxiv.org/find/hep-th/1/au:+Pietro_L/0/1/0/all/0/1">Lorenzo Di Pietro</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Gorbenko_V/0/1/0/all/0/1">Victor Gorbenko</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Komatsu_S/0/1/0/all/0/1">Shota Komatsu</a> We study the fundamentals of quantum field theory on a rigid de Sitter space. We show that the perturbative expansion of late-time correlation functions to all orders can be equivalently generated by a non-unitary Lagrangian on a Euclidean AdS geometry. This finding simplifies dramatically perturbative computations, as well as allows us to establish basic properties of these correlators, which comprise a Euclidean CFT. We use this to infer the analytic structure of the spectral density that captures the conformal partial wave expansion of a late-time four-pointRead More →

A New Catalog of Asymptotic Giant Branch Stars in Our Galaxy. (arXiv:2107.02350v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Suh_K/0/1/0/all/0/1">Kyung-Won Suh</a> We present a new catalog of 11,209 O-rich AGB stars and 7172 C-rich AGB stars in our Galaxy identifying more AGB stars in the bulge component and considering more visual carbon stars. For each object, we cross-identify the IRAS, AKARI, MSX, WISE, 2MASS, and AAVSO counterparts. We present the new catalog in two parts: one is based on the IRAS PSC for brighter or more isolated objects; the other one is based on the ALLWISE source catalog for less bright objects or objects in crowded regions. We presentRead More →

Polarized Image of Equatorial Emission in the Kerr Geometry. (arXiv:2105.09440v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Gelles_Z/0/1/0/all/0/1">Zachary Gelles</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Himwich_E/0/1/0/all/0/1">Elizabeth Himwich</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Palumbo_D/0/1/0/all/0/1">Daniel C.M. Palumbo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Johnson_M/0/1/0/all/0/1">Michael D. Johnson</a> We develop a simple toy model for polarized images of synchrotron emission from an equatorial source around a Kerr black hole by using a semi-analytic solution of the null geodesic equation and conservation of the Penrose-Walker constant. Our model is an extension of Narayan et al. (2021), which presented results for a Schwarzschild black hole, including a fully analytic approximation. Our model includes an arbitrary observer inclination, black hole spin, local boost, and local magnetic field configuration. We studyRead More →

Surface rotation and photometric activity for Kepler targets. II. G and F main-sequence stars, and cool subgiant stars. (arXiv:2107.02217v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Santos_A/0/1/0/all/0/1">A. R. G. Santos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Breton_S/0/1/0/all/0/1">S. N. Breton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mathur_S/0/1/0/all/0/1">S. Mathur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_R/0/1/0/all/0/1">R. A. Garc&#xed;a</a> Dark magnetic spots crossing the stellar disc lead to quasi-periodic brightness variations, which allow us to constrain stellar surface rotation and photometric activity. The current work is the second of this series (Santos et al. 2019; Paper I), where we analyze the Kepler long-cadence data of 132,921 main-sequence F and G stars and late subgiant stars. Rotation-period candidates are obtained by combining wavelet analysis with autocorrelation function. ReliableRead More →

The Skipper CCD for low-energy threshold particle experiments above ground. (arXiv:2107.00168v2 [hep-ex] UPDATED) <a href="http://arxiv.org/find/hep-ex/1/au:+Moroni_G/0/1/0/all/0/1">Guillermo Fernandez Moroni</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Chierchie_F/0/1/0/all/0/1">Fernando Chierchie</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Tiffenberg_J/0/1/0/all/0/1">Javier Tiffenberg</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Botti_A/0/1/0/all/0/1">Ana Botti</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Cababie_M/0/1/0/all/0/1">Mariano Cababie</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Cancelo_G/0/1/0/all/0/1">Gustavo Cancelo</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Depaoli_E/0/1/0/all/0/1">Eliana L. Depaoli</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Estrada_J/0/1/0/all/0/1">Juan Estrada</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Holland_S/0/1/0/all/0/1">Stephen E. Holland</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Rodrigues_D/0/1/0/all/0/1">Dario Rodrigues</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Sidelnik_I/0/1/0/all/0/1">Iv&#xe1;n Sidelnik</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Haro_M/0/1/0/all/0/1">Miguel Sofo Haro</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Stefanazzi_L/0/1/0/all/0/1">Leandro Stefanazzi</a>, <a href="http://arxiv.org/find/hep-ex/1/au:+Uemura_S/0/1/0/all/0/1">Sho Uemura</a> We present experimental results using a single-electron resolution Skipper-CCD running above ground level to demonstrate the potential of this technology for its use in reactor neutrino observations and other low-energy particle interaction experiments. Operating conditions and event-selection criteria are provided to decouple most of the backgroundRead More →

On the most constraining cosmological neutrino mass bounds. (arXiv:2106.15267v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Valentino_E/0/1/0/all/0/1">Eleonora Di Valentino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gariazzo_S/0/1/0/all/0/1">Stefano Gariazzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mena_O/0/1/0/all/0/1">Olga Mena</a> We present here up-to-date neutrino mass limits exploiting the most recent cosmological data sets. By making use of the Cosmic Microwave Background temperature fluctuation and polarization measurements, Supernovae Ia luminosity distances, Baryon Acoustic Oscillation observations and determinations of the growth rate parameter, we are able to set the most constraining bound to date, $sum m_nu<0.09$ eV at $95%$~CL. This very tight limit is obtained without the assumption of any prior on the value of the Hubble constant and highly compromises the viability of theRead More →

Penrose process for a charged black hole in a uniform magnetic field. (arXiv:2106.15010v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Gupta_K/0/1/0/all/0/1">Kshitij Gupta</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Law_Y/0/1/0/all/0/1">Y.T. Albert Law</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Levin_J/0/1/0/all/0/1">Janna Levin</a> Spinning black holes create electromagnetic storms when immersed in ambient magnetic fields, illuminating the otherwise epically dark terrain. In an electromagnetic extension of the Penrose process, tremendous energy can be extracted, boosting the energy of radiating particles far more efficiently than the mechanical Penrose process. We locate the regions from which energy can be mined and demonstrate explicitly that they are no longer restricted to the ergosphere. We also show that there can be toroidal regions that trap negative energyRead More →

Feeble DM-SM Interaction via New Scalar and Vector Mediators in Rotating Neutron Stars. (arXiv:2106.10353v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Guha_A/0/1/0/all/0/1">Atanu Guha</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Sen_D/0/1/0/all/0/1">Debashree Sen</a> We investigate the possible presence of dark matter (DM) in massive and rotating neutron stars (NSs). For the purpose we extend our previous work [1] to introduce a light new physics vector mediator besides a scalar one in order to ensure feeble interaction between fermionic DM and $beta$ stable hadronic matter in NSs. The masses of DM fermion, the mediators and the couplings are chosen consistent with the self-interaction constraint from Bullet cluster and from present day relic abundance. Assuming that both theRead More →