RAS_WEB (Page 2)

Orbit decay in encounters between anisotropic spherical galaxies of equal mass. (arXiv:2312.00263v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Saleh_L/0/1/0/all/0/1">Lucas Saleh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barnes_J/0/1/0/all/0/1">Joshua E. Barnes</a> We investigate the effect of radial anisotropy on the rate of orbit decay in parabolic encounters of identical spherical galaxies. Our galaxy models have Hernquist density profiles and Osipkov–Merritt velocity distributions. We find that radially anisotropic models merge in as little as half the time of their isotropic counterparts. Anisotropic models are more susceptible to tidal deformation; this accelerates the transfer of orbital angular momentum to internal degrees of freedom. Even during the initial approach, the anisotropic models become more distorted, and arrive at pericentreRead More →

aeons: approximating the end of nested sampling. (arXiv:2312.00294v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_Z/0/1/0/all/0/1">Zixiao Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baryshnikov_A/0/1/0/all/0/1">Artem Baryshnikov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Handley_W/0/1/0/all/0/1">Will Handley</a> This paper presents analytic results on the anatomy of nested sampling, from which a technique is developed to estimate the run-time of the algorithm that works for any nested sampling implementation. We test these methods on both toy models and true cosmological nested sampling runs. The method gives an order-of-magnitude prediction of the end point at all times, forecasting the true endpoint within standard error around the halfway point. This paper presents analytic results on the anatomy of nested sampling, from which a technique is developed toRead More →

A Large Sample of Extremely Metal-poor Galaxies at $zRead More →

RadioGalaxyNET: Dataset and Novel Computer Vision Algorithms for the Detection of Extended Radio Galaxies and Infrared Hosts. (arXiv:2312.00306v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Gupta_N/0/1/0/all/0/1">Nikhel Gupta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayder_Z/0/1/0/all/0/1">Zeeshan Hayder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Norris_R/0/1/0/all/0/1">Ray P. Norris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huynh_M/0/1/0/all/0/1">Minh Huynh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petersson_L/0/1/0/all/0/1">Lars Petersson</a> Creating radio galaxy catalogues from next-generation deep surveys requires automated identification of associated components of extended sources and their corresponding infrared hosts. In this paper, we introduce RadioGalaxyNET, a multimodal dataset, and a suite of novel computer vision algorithms designed to automate the detection and localization of multi-component extended radio galaxies and their corresponding infrared hosts. The dataset comprises 4,155 instances of galaxies in 2,800 images with both radio andRead More →

VLBI detection of the AE Aqr twin, LAMOST J024048.51+195226.9. (arXiv:2312.00307v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_P/0/1/0/all/0/1">Pengfei Jiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cui_L/0/1/0/all/0/1">Lang Cui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_X/0/1/0/all/0/1">Xiang Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bo Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_Y/0/1/0/all/0/1">Yongfeng Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cao_H/0/1/0/all/0/1">Hongmin Cao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+An_T/0/1/0/all/0/1">Tao An</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_J/0/1/0/all/0/1">Jun Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shu_F/0/1/0/all/0/1">Fengchun Shu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tan_G/0/1/0/all/0/1">Guiping Tan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_J/0/1/0/all/0/1">Jianping Yuan</a> LAMOST J024048.51+195226.9 (J0240+1952) was recently identified as the second AE Aquarii (AE Aqr)-type cataclysmic variable, possessing the fastest known rotating white dwarf. We performed a Very Long Baseline Interferometry (VLBI) observation of J0240+1952 utilizing the European VLBI Network at 1.7,GHz, to obtain the first view of the radio morphology on mas scale. Our high-resolution VLBI image clearly shows that the radioRead More →

Three-Dimensional Reconstruction of Weak-Lensing Mass Maps with a Sparsity Prior. II. Weighing Triaxial Cluster Halos. (arXiv:2312.00309v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_S/0/1/0/all/0/1">Shouzhuo Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_X/0/1/0/all/0/1">Xiangchong Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yoshida_N/0/1/0/all/0/1">Naoki Yoshida</a> Continuing work presented in Li et al. (2021), we performed a series of tests to our high-resolution three-dimensional mass map reconstruction algorithm splinv{}. We test the mass reconstruction accuracy against realistic mock catalogs generated using shear field produced by triaxial halos with the inner density profile of $rho propto r^{-1}$ and of $rho propto r^{-1.5}$. The galaxy shape noise is modeled based on the Year-1 Subaru Hyper Suprime-Cam (HSC) Survey. After reviewing mathematical details of our algorithm and darkRead More →

Spherically symmetric anisotropic strange stars. (arXiv:2312.00310v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Lopes_L/0/1/0/all/0/1">Luiz L. Lopes</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Das_H/0/1/0/all/0/1">H. C. Das</a> In this work, we made an extensive study about the possible presence of anisotropies in strange stars. To accomplish this task, we use three different configurations for the strange matter: the unpaired matter, a two-flavor super-conducting (2SC) strange matter, and a fully three-flavor super-conducting strange matter (CFL). For each configuration, we calculate the relevant quantities for the strange stars, such as the mass-radius relation, the dimensionless tidal parameter, the moment of inertia, and the surface curvature for different degrees of anisotropies. Whenever possible, we compare our results with constraints foundRead More →

The Magnetic Field Calibration of the Full-Disk Magnetograph onboard the Advanced Space based Solar Observatory (ASO-S/FMG). (arXiv:2312.00319v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_S/0/1/0/all/0/1">S. Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Su_J/0/1/0/all/0/1">J.T. Su</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_X/0/1/0/all/0/1">X.Y. Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deng_Y/0/1/0/all/0/1">Y.Y. Deng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_J/0/1/0/all/0/1">J. Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Song_Y/0/1/0/all/0/1">Y.L. Song</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_X/0/1/0/all/0/1">X.F. Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_H/0/1/0/all/0/1">H.Q. Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">X. Yang</a> The Full-disk magnetograph is a main scientific payload onboard the Advanced Space based Solar Observatory (ASO-S/FMG) that through Stokes parameter observation to measures the vector magnetic field. The accuracy of magnetic-field values is an important aspect of checking the quality of the FMG magnetic-field measurement. According to the design of the FMG, the linear calibration method under the weak-field approximationRead More →

Merger rate of supermassive primordial black hole binaries. (arXiv:2312.00338v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_H/0/1/0/all/0/1">Hai-Long Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_J/0/1/0/all/0/1">Jun-Qian Jiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piao_Y/0/1/0/all/0/1">Yun-Song Piao</a> The probability that the primordial black hole (PBH) binaries formed in the early Universe can be affected by the Hubble expansion of background, which is non-negligible when the number density of PBHs is very low (it is actually this case for supermassive PBHs). In this paper, taking into account the effect of cosmic expansion on the comoving distance of PBH pairs, we worked out the merger rate of PBHs with any extended mass function. The torques by all PBHs and linear density perturbations are also considered.Read More →

White Paper and Roadmap for Quantum Gravity Phenomenology in the Multi-Messenger Era. (arXiv:2312.00409v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Batista_R/0/1/0/all/0/1">R. Alves Batista</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Amelino_Camelia_G/0/1/0/all/0/1">G. Amelino-Camelia</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Boncioli_D/0/1/0/all/0/1">D. Boncioli</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Carmona_J/0/1/0/all/0/1">J. M. Carmona</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Matteo_A/0/1/0/all/0/1">A. di Matteo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Gubitosi_G/0/1/0/all/0/1">G. Gubitosi</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Lobo_I/0/1/0/all/0/1">I. Lobo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Mavromatos_N/0/1/0/all/0/1">N. E. Mavromatos</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Pfeifer_C/0/1/0/all/0/1">C. Pfeifer</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Rubiera_Garcia_D/0/1/0/all/0/1">D. Rubiera-Garcia</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Saridakis_E/0/1/0/all/0/1">E. N. Saridakis</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Terzic_T/0/1/0/all/0/1">T. Terzi&#x107;</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Vagenas_E/0/1/0/all/0/1">E. C. Vagenas</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Moniz_P/0/1/0/all/0/1">P. Vargas Moniz</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Abdalla_H/0/1/0/all/0/1">H. Abdalla</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Adamo_M/0/1/0/all/0/1">M. Adamo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Anagnostopoulos_F/0/1/0/all/0/1">F. K. Anagnostopoulos</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Antonelli_V/0/1/0/all/0/1">V. Antonelli</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Asorey_M/0/1/0/all/0/1">M. Asorey</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Ballesteros_A/0/1/0/all/0/1">A. Ballesteros</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Benisty_D/0/1/0/all/0/1">D. Benisty</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Boettcher_M/0/1/0/all/0/1">M. Boettcher</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Bolmont_J/0/1/0/all/0/1">J. Bolmont</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Bonilla_A/0/1/0/all/0/1">A. Bonilla</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Bosso_P/0/1/0/all/0/1">P. Bosso</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Bouhmadi_Lopez_M/0/1/0/all/0/1">M. Bouhmadi-L&#xf3;pez</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Burderi_L/0/1/0/all/0/1">L. Burderi</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Campoy_Ordaz_A/0/1/0/all/0/1">A.Read More →

New Continuum Observations of the Andromeda galaxy M31 with FAST. (arXiv:2312.00441v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_W/0/1/0/all/0/1">Wenjun Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sun_X/0/1/0/all/0/1">Xiaohui Sun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Jie Wang</a> We present a new total intensity image of M31 at 1.248 GHz, observed with the Five-hundred-meter Aperture Spherical radio telescope (FAST) with an angular resolution of 4 arcmin and a sensitivity of about 16 mK. The new FAST image clearly reveals weak emission outside the ring due to its high sensitivity on large-scale structures. We derive a scale length of 2.7 kpc for the cosmic ray electrons and find that the cosmic ray electrons propagate mainly through diffusion by comparing the scale length atRead More →

Dynamics of pairwise motions in the fully non-linear regime in LCDM and Modified Gravity cosmologies. (arXiv:2312.00472v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Jaber_M/0/1/0/all/0/1">Mariana Jaber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hellwing_W/0/1/0/all/0/1">Wojciech A. Hellwing</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_Farieta_J/0/1/0/all/0/1">Jorge E. Garc&#xed;a-Farieta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gupta_S/0/1/0/all/0/1">Suhani Gupta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bilicki_M/0/1/0/all/0/1">Maciej Bilicki</a> In contrast to our understanding of density field tracers, the modelling of direct statistics pertaining to the cosmic velocity field remains open to significant opportunities for improvement. The lack of accurate modelling for the non-linear domain of pairwise velocities restricts our capacity to fully exploit the information encoded in this observable. We present a robust approach for modelling the mean infall velocities, $v_{12}(r,a)$, with broad applicability spanning sub-megaparsec scales and cosmologiesRead More →

Constraining tensor-to-scalar ratio based on VLBI observations: PGWs induced-incoherence approach. (arXiv:2312.00474v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Arani_F/0/1/0/all/0/1">Fateme Shojaei Arani</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Harouni_M/0/1/0/all/0/1">Malek Bagheri Harouni</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Lamine_B/0/1/0/all/0/1">Brahim Lamine</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Blanchard_A/0/1/0/all/0/1">Alain Blanchard</a> The background of primordial gravitational waves (PGWs) predicted by the inflationary scenario induce incoherence of the electromagnetic field propagating over cosmological distances. We propose a new schema to constrain the underlying inflationary parameters, in particular the tensor-to-scalar ratio r, based on angular size-redshift theta-z measurement accomplished by very long baseline interferometry (VLBI) surveys. VLBI observations rely on the van-Citter Zernike theorem, which expresses the coherence length in terms of its wavelength and angular size, i.e., d_coh < lambda/theta. InRead More →

GaiaNIR: Note on processing and photometry. (arXiv:2312.00488v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Hog_E/0/1/0/all/0/1">Erik H&#xf8;g</a> Some ideas for onboard processing and photometry with an astrometry satellite are presented, especially designed for GaiaNIR which may be launched about 2045 as a successor of Gaia. – Increased sensitivity, reduced image overlap, and simpler PSF calibration in GaiaNIR will result if the proposed initial processing of data from the detectors is implemented, because the across-scan smearing will become insignificant. – Filter photometry is required for high angular resolution as needed for astrometric and astrophysical reasons. Low-dispersion spectra are questioned because they fail at high star density. This will be a much greaterRead More →

The maximum mass of a black hole which can tidally disrupt a star: measuring black hole spins with tidal disruption events. (arXiv:2312.00557v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Mummery_A/0/1/0/all/0/1">Andrew Mummery</a> The tidal acceleration experienced by an object at the event horizon of a black hole decreases as one over the square of the black hole’s mass. As such there is a maximum mass at which a black hole can tidally disrupt an object outside of its event horizon and potentially produce observable emission. This maximum mass is known as the “Hills mass”, and in full general relativity is a function of both the black hole’s spin $a_bullet$ and theRead More →