RAS_WEB (Page 2,274)

Cross-correlations as a Diagnostic Tool for Primordial Gravitational Waves. (arXiv:2012.03498v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Malhotra_A/0/1/0/all/0/1">Ameek Malhotra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dimastrogiovanni_E/0/1/0/all/0/1">Ema Dimastrogiovanni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fasiello_M/0/1/0/all/0/1">Matteo Fasiello</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shiraishi_M/0/1/0/all/0/1">Maresuke Shiraishi</a> We explore and corroborate, by working out explicit examples, the effectiveness of cross-correlating stochastic gravitational wave background anisotropies with CMB temperature fluctuations as a way to establish the primordial nature of a given gravitational wave signal. We consider the case of gravitational wave anisotropies induced by scalar-tensor-tensor primordial non-Gaussianity. Our analysis spans anisotropies exhibiting different angular behaviours, including a quadrupolar dependence. We calculate the expected uncertainty on the non-linearity parameter $F_{rm NL}$ obtained as a result of cross-correlation measurements for severalRead More →

Strategies to Detect Dark-Matter Decays with Line-Intensity Mapping. (arXiv:2012.00771v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Bernal_J/0/1/0/all/0/1">Jos&#xe9; Luis Bernal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caputo_A/0/1/0/all/0/1">Andrea Caputo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kamionkowski_M/0/1/0/all/0/1">Marc Kamionkowski</a> The nature of dark matter is a longstanding mystery in cosmology, which can be studied with laboratory or collider experiments, as well as astrophysical and cosmological observations. In this work, we propose realistic and efficient strategies to detect radiative products from dark-matter decays with line-intensity mapping (LIM) experiments. This radiation will behave as a line interloper for the atomic and molecular spectral lines targeted by LIM surveys. The most distinctive signatures of the contribution from dark-matter radiative decays are an extra anisotropy on theRead More →

Combinative Isobaric Resonances CIRs by MSS and from previous precise data. (arXiv:2011.09131v3 [nucl-ex] UPDATED) <a href="http://arxiv.org/find/nucl-ex/1/au:+Gafarov_A/0/1/0/all/0/1">A. Gafarov</a> The elastic scattering {12}^C(p,p{o}_) Excitation Function (EF) was measured in the energy range Ep =16 – 19.5 MeV with resolution about 10 keV by means of innovative approach – MSS – the Method of Spectra Superposition at the 14-angle Magnetic Spectrograph (Apelsin) at beam with an energy spread of about 200 keV from U-150 cyclotron of INP Ulugbek (Tashkent) of Science Academy of Uzbekistan [1-9]. The obtained EF has a reach structure of anomalies in precise agreement with thresholds and levels data [2,10-12]. Measurements were done on theRead More →

Cosmology with Standard Sirens at Cosmic Noon. (arXiv:2103.14038v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ye_C/0/1/0/all/0/1">Christine Ye</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fishbach_M/0/1/0/all/0/1">Maya Fishbach</a> Gravitational waves (GWs) from merging black holes and neutron stars directly measure the luminosity distance to the merger, which, when combined with an independent measurement of the source’s redshift, provides a novel probe of cosmology. The proposed next generation of ground-based GW detectors, Einstein Telescope and Cosmic Explorer, will detect tens of thousands of binary neutron stars (BNSs) out to cosmological distances ($z>2$), beyond the peak of the star formation rate (SFR), or “cosmic noon.” At these distances, it will be challenging to measure the sources’ redshifts by observing electromagneticRead More →

Revisiting KELT-19Ab, WASP-156b and WASP-121b in the TESS Era. (arXiv:2012.08744v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_F/0/1/0/all/0/1">Fan Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chary_R/0/1/0/all/0/1">Ranga-Ram Chary</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Ji-Feng Liu</a> We present a re-analysis of transit depths of KELT-19Ab, WASP-156b, and WASP-121b, including data from the Transiting Exoplanet Survey Satellite (TESS). The large $sim21”$ TESS pixels and point spread function results in significant contamination of the stellar flux by nearby objects. We use Gaia data to fit for and remove this contribution, providing general-purpose software for this correction. We find all the three sources have a larger inclination, compared to earlier work. For WASP-121b, we find significantly smaller values (13.5 degrees) of the inclinationRead More →

A comparative study of the strength of flickering in cataclysmic variables. (arXiv:2103.14521v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bruch_A/0/1/0/all/0/1">Albert Bruch</a> Flickering is a universal phenomenon in accreting astronomical systems which still defies detailed physical understanding. It is particularly evident in cataclysmic variables (CVs). Attempting to define boundary conditions for models, the strength of the flickering is measured in several thousand light curves of more than 100 CVs. The flickering amplitude is parameterized by the FWHM of a Gaussian fit to the magnitude distribution of data points in a light curve. This quantity requires several corrections before a comparison between different sources can be made. While no correlations of theRead More →

The rare X-ray flaring activity of the Ultraluminous X-ray source NGC 4559 X7. (arXiv:2103.14541v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Pintore_F/0/1/0/all/0/1">Fabio Pintore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Motta_S/0/1/0/all/0/1">S. Motta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pinto_C/0/1/0/all/0/1">C. Pinto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardini_M/0/1/0/all/0/1">M.G. Bernardini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rodriguez_Castillo_G/0/1/0/all/0/1">G. Rodriguez-Castillo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salvaterra_R/0/1/0/all/0/1">R. Salvaterra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Israel_G/0/1/0/all/0/1">G. L. Israel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Esposito_P/0/1/0/all/0/1">P. Esposito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ambrosi_E/0/1/0/all/0/1">E. Ambrosi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salvaggio_C/0/1/0/all/0/1">C. Salvaggio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zampieri_L/0/1/0/all/0/1">L. Zampieri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wolter_A/0/1/0/all/0/1">A. Wolter</a> Ultraluminous X-ray sources are considered amongst the most extremely accreting objects in the local Universe. The recent discoveries of pulsating neutron stars in ULXs strengthened the scenario of highly super-Eddington accretion mechanisms on stellar mass compact objects. In this work, we present the first long-term light curve of the source NGC 4559 X7Read More →

Extracting the Optical Depth to Reionization $tau$ from 21 cm Data Using Machine Learning Techniques. (arXiv:2103.14563v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Billings_T/0/1/0/all/0/1">Tashalee S. Billings</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Plante_P/0/1/0/all/0/1">Paul La Plante</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aguirre_J/0/1/0/all/0/1">James E. Aguirre</a> Upcoming measurements of the high-redshift 21 cm signal from the Epoch of Reionization (EoR) are a promising probe of the astrophysics of the first galaxies and of cosmological parameters. In particular, the optical depth $tau$ to the last scattering surface of the cosmic microwave background (CMB) should be tightly constrained by direct measurements of the neutral hydrogen state at high redshift. A robust measurement of $tau$ from 21 cm data would help eliminate it as aRead More →

An exploration of model degeneracies with a unified phase curve retrieval analysis: The light and dark sides of WASP-43 b. (arXiv:2103.14566v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Changeat_Q/0/1/0/all/0/1">Quentin Changeat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Al_Refaie_A/0/1/0/all/0/1">Ahmed F. Al-Refaie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Edwards_B/0/1/0/all/0/1">Billy Edwards</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Waldmann_I/0/1/0/all/0/1">Ingo P. Waldmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tinetti_G/0/1/0/all/0/1">Giovanna Tinetti</a> The analysis of exoplanetary atmospheres often relies upon the observation of transit or eclipse events. While very powerful, these snapshots provide mainly 1-dimensional information on the planet structure and do not easily allow precise latitude-longitude characterisations. The phase curve technique, which consists of measuring the planet emission throughout its entire orbit, can break this limitation and provide useful 2-dimensional thermal and chemical constraints on the atmosphere.Read More →

Cosmic tango between the very small and the very large: Addressing CMB anomalies through Loop Quantum Cosmology. (arXiv:2103.14568v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Ashtekar_A/0/1/0/all/0/1">Abhay Ashtekar</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Gupt_B/0/1/0/all/0/1">Brajesh Gupt</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Sreenath_V/0/1/0/all/0/1">V. Sreenath</a> While the standard, six-parameter, spatially flat $Lambda$CDM model has been highly successful, certain anomalies in the cosmic microwave background bring out a tension between this model and observations. The statistical significance of any one anomaly is small. However, taken together, the presence of two or more of them imply that according to standard inflationary theories we live in quite an exceptional universe. We revisit the analysis of the PLANCK collaboration using loop quantum cosmology, where an unforeseenRead More →

Characterization of the stochastic signal originating from compact binaries populations as measured by LISA. (arXiv:2103.14598v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Karnesis_N/0/1/0/all/0/1">Nikolaos Karnesis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Babak_S/0/1/0/all/0/1">Stanislav Babak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pieroni_M/0/1/0/all/0/1">Mauro Pieroni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cornish_N/0/1/0/all/0/1">Neil Cornish</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Littenberg_T/0/1/0/all/0/1">Tyson Littenberg</a> The Laser Interferometer Space Antenna (LISA) mission, scheduled for launch in the early 2030s, is a gravitational wave observatory in space designed to detect sources emitting in the milli-Hertz band. In contrast to the present ground based detectors, the LISA data are expected to be a signaldominated, with strong and weak gravitational wave signals overlapping in time and in frequency. Astrophysical population models predict a sufficient number of signals in the LISA band toRead More →

Chiral Anomaly in SU(2)${}_R$-Axion Inflation and the New Prediction for Particle Cosmology. (arXiv:2103.14611v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Maleknejad_A/0/1/0/all/0/1">Azadeh Maleknejad</a> Upon embedding the axion-inflation in the minimal left-right symmetric gauge extension of the SM with gauge group $SU(2)_Ltimes SU(2)_R times U(1)_{B-L}$, [arXiv:2012.11516] proposed a new particle physics model for inflation. In this work, we present a more detailed analysis. As a compelling consequence, this setup provides a new mechanism for simultaneous baryogenesis and right-handed neutrino creation by the chiral anomaly of $W_R$ in inflation. The lightest right-handed neutrino is the dark matter candidate. This setup has two unknown fundamental scales, i.e., the scale of inflation and left-right symmetryRead More →

Activity of the Jupiter co-orbital comet P/2019~LD$_{2}$ (ATLAS) observed with OSIRIS at the 10.4 m GTC. (arXiv:2103.14613v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Licandro_J/0/1/0/all/0/1">J. Licandro</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Leon_J/0/1/0/all/0/1">J. de Leon</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Moreno_F/0/1/0/all/0/1">F. Moreno</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Marcos_C/0/1/0/all/0/1">C. de la Fuente Marcos</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Marcos_R/0/1/0/all/0/1">R. de la Fuente Marcos</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Cabrera_Lavers_A/0/1/0/all/0/1">A. Cabrera-Lavers</a> (6,1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Lara_L/0/1/0/all/0/1">L. Lara</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Souza_Feliciano_A/0/1/0/all/0/1">A. de Souza-Feliciano</a> (7), <a href="http://arxiv.org/find/astro-ph/1/au:+Pra_M/0/1/0/all/0/1">M. De Pr&#xe1;</a> (8), <a href="http://arxiv.org/find/astro-ph/1/au:+Pinilla_Alonso_N/0/1/0/all/0/1">N.Pinilla-Alonso</a> (8), <a href="http://arxiv.org/find/astro-ph/1/au:+Geier_S/0/1/0/all/0/1">S. Geier</a> (6,1) Jupiter co-orbital comets have orbits that are not long-term stable. They may experience flybys with Jupiter close enough to trigger tidal disruptions like the one suffered by comet Shoemaker-Levy 9. Our aim was to studyRead More →

Solar Wind Helium Abundance Heralds Solar Cycle Onset. (arXiv:2006.04669v3 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Alterman_B/0/1/0/all/0/1">B. L. Alterman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kasper_J/0/1/0/all/0/1">Justin C. Kasper</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leamon_R/0/1/0/all/0/1">Robert J. Leamon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McIntosh_S/0/1/0/all/0/1">Scott W. McIntosh</a> We study the solar wind helium-to-hydrogen abundance’s ($A_mathrm{He}$) relationship to solar cycle onset. Using OMNI/Lo data, we show that $A_mathrm{He}$ increases prior to sunspot number (SSN) minima. We also identify a rapid depletion and recovery in $A_mathrm{He}$ that occurs directly prior to cycle onset. This $A_mathrm{He}$ Shutoff happens at approximately the same time across solar wind speeds ($v_mathrm{sw}$), implying that it is formed by a mechanism distinct from the one that drives $A_mathrm{He}$’s solar cycle scale variation andRead More →

The Distribution and Evolution of Quasar Proximity Zone Sizes. (arXiv:2008.04911v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_H/0/1/0/all/0/1">Huanqing Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gnedin_N/0/1/0/all/0/1">Nickolay Y. Gnedin</a> In this paper, we study the sizes of quasar proximity zones with synthetic quasar absorption spectra obtained by post-processing a Cosmic Reionization On Computers (CROC) simulation. CROC simulations have both relatively large box sizes and high spacial resolution, allowing us to resolve Lyman limit systems, which are crucial for modeling the quasar absorption spectra. We find that before reionization most quasar proximity zone sizes grow steadily for $sim 10$ Myr, while after reionization they grow rapidly but only for $sim 0.1$ Myr. We also find aRead More →

Applications of the Hawking Energy in Inhomogeneous Cosmology. (arXiv:2010.07896v3 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Stock_D/0/1/0/all/0/1">Dennis Stock</a> The past lightcone of an observer in a cosmological spacetime is the unique geometric structure directly linked to observations. After general properties of the Hawking energy along slices of the past lightcone have previously been studied, the present work continues along this path by providing explicit cosmological applications of the Hawking energy associated with a lightcone. Firstly, it is shown that amongst all two-dimensional non-trapped spheres with equal area and average matter density, a shear-free matter distribution maximizes the Hawking energy for sufficiently high densities. Secondly, a Robertson-Walker reference slice isRead More →

Fast magnetic reconnection structures in Poynting-flux dominated jets. (arXiv:2011.03634v3 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Kadowaki_L/0/1/0/all/0/1">Lu&#xed;s H.S Kadowaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pino_E/0/1/0/all/0/1">Elisabete M. de Gouveia Dal Pino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Torrejon_T/0/1/0/all/0/1">Tania E. Medina Torrejon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mizuno_Y/0/1/0/all/0/1">Yosuke Mizuno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kushwaha_P/0/1/0/all/0/1">Pankaj Kushwaha</a> The ubiquitous relativistic jet phenomena associated with black holes play a major role in high and very-high-energy (VHE) astrophysics. In particular, observations have demonstrated that blazars show VHE emission with time-variability from days (in the GeV band) to minutes (in the TeV band), implying very compact emission regions. The real mechanism able to explain the particle acceleration process responsible for this emission is still debated, but magnetic reconnection has been lately discussedRead More →

On the duration of the embedded phase of star formation. (arXiv:2012.00019v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_J/0/1/0/all/0/1">Jaeyeon Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chevance_M/0/1/0/all/0/1">M&#xe9;lanie Chevance</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kruijssen_J/0/1/0/all/0/1">J. M. Diederik Kruijssen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schruba_A/0/1/0/all/0/1">Andreas Schruba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sandstrom_K/0/1/0/all/0/1">Karin Sandstrom</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barnes_A/0/1/0/all/0/1">Ashley T. Barnes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bigiel_F/0/1/0/all/0/1">Frank Bigiel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blanc_G/0/1/0/all/0/1">Guillermo A. Blanc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cao_Y/0/1/0/all/0/1">Yixian Cao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dale_D/0/1/0/all/0/1">Daniel A. Dale</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faesi_C/0/1/0/all/0/1">Christopher M. Faesi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Glover_S/0/1/0/all/0/1">Simon C. O. Glover</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grasha_K/0/1/0/all/0/1">Kathryn Grasha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Groves_B/0/1/0/all/0/1">Brent Groves</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Herrera_C/0/1/0/all/0/1">Cinthya Herrera</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Klessen_R/0/1/0/all/0/1">Ralf S. Klessen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kreckel_K/0/1/0/all/0/1">Kathryn Kreckel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_J/0/1/0/all/0/1">Janice C. Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leroy_A/0/1/0/all/0/1">Adam K. Leroy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pety_J/0/1/0/all/0/1">J&#xe9;r&#xf4;me Pety</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Querejeta_M/0/1/0/all/0/1">Miguel Querejeta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schinnerer_E/0/1/0/all/0/1">Eva Schinnerer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sun_J/0/1/0/all/0/1">Jiayi Sun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Usero_A/0/1/0/all/0/1">Antonio Usero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ward_J/0/1/0/all/0/1">Jacob L. Ward</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Williams_T/0/1/0/all/0/1">Thomas G. Williams</a> FeedbackRead More →

Cosmology with galaxy cluster weak lensing: statistical limits and experimental design. (arXiv:2012.01956v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_H/0/1/0/all/0/1">Hao-Yi Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weinberg_D/0/1/0/all/0/1">David H. Weinberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salcedo_A/0/1/0/all/0/1">Andr&#xe9;s N. Salcedo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wibking_B/0/1/0/all/0/1">Benjamin D. Wibking</a> We forecast constraints on the amplitude of matter clustering sigma_8(z) achievable with the combination of cluster weak lensing and number counts, in current and next-generation weak lensing surveys. We advocate an approach, analogous to galaxy-galaxy lensing, in which the observables in each redshift bin are the mean number counts and the mean weak lensing profile of clusters above a mass proxy threshold. The primary astrophysical nuisance parameter is the logarithmic scatter between the mass proxy andRead More →