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Venus was observed at frequencies of 1297.67 MHz (23 cm), 607.67 MHz (49 cm) and 233.67 MHz (1.28 m) with the Giant Metrewave Radio Telescope (GMRT) during the period of 25th July and 6th September 2015 when it was close to its inferior…

Earth and Planetary Astrophysics · Physics 2019-06-19 Nithin Mohan , Suresh Raju C , Govind Swarup , Divya Oberoi

We critically examine recent claims challenging the viability of the G-step model (GSM) as a solution to the Hubble tension. The GSM proposes a $\sim$4 % increase in the effective gravitational constant $G_{\text{eff}}$ beyond $z \approx…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-07 Leandros Perivolaropoulos , Ruchika

RadioAstron satellite admits in principle a testing the gravitational redshift effect with an accuracy of better than $10^{-5}$. It would surpass the result of Gravity Probe A mission at least an order of magnitude. However, RadioAstron's…

Instrumentation and Methods for Astrophysics · Physics 2015-06-09 A. V. Birukov , V. L. Kauts , D. A. Litvinov , N. K. Porayko , V. N. Rudenko

A comparison of a 19 GHz full-sky map with the WMAP satellite K band (23 GHz) map indicates that the bulk of the 20 GHz emission within 7 degrees of the Galactic plane has an inverted (rising) spectrum with an average spectral index alpha =…

Astrophysics · Physics 2011-02-11 S. P. Boughn , J. C. Pober

We study the propagation of cosmological gravitational wave (GW) backgrounds from the early radiation era until the present day in modified theories of gravity. Comparing to general relativity (GR), we study the effects that modified…

General Relativity and Quantum Cosmology · Physics 2023-06-21 Yutong He , Alberto Roper Pol , Axel Brandenburg

We present the results of a search for gravitational waves (GWs) from individual sources using high-cadence observations of PSR J1909\(-\)3744 obtained during an intensive observing campaign with the International Pulsar Timing Array second…

High Energy Astrophysical Phenomena · Physics 2026-03-13 Jing Zou , Jingbo Wang Jianping Yuan , De Zhao , Yirong Wen , Wei Li , Na Wang , Yong Xia

The estimation of the Hubble constant in the past few decades has increasingly become more accurate with the advance of new techniques. But its value seems to depend on the epoch at which the measurements are made. The Planck estimate of…

General Relativity and Quantum Cosmology · Physics 2024-07-30 Louise Rebecca , C Sivaram , Dominic Sebastian , Kenath Arun

We present an approach to experimentally evaluate gravity gradient noise, a potentially limiting noise source in advanced interferometric gravitational wave (GW) detectors. In addition, the method can be used to provide sub-percent…

General Relativity and Quantum Cosmology · Physics 2008-11-26 L. Matone , P. Raffai , S. Marka , R. Grossman , P. Kalmus , Z. Marka , J. Rollins , V. Sannibale

GRBs are now detected up to z = 8.26 . We try to find differences, in their restframe properties, which could be related either to distance or to observing conditions.

High Energy Astrophysical Phenomena · Physics 2009-12-16 G. Pizzichini , E. Maiorano , M. Genghini , F. Munz

In general relativity gravitational waves propagate at the speed of light, however in alternative theories of gravity that might not be the case. We study the effects of a modified speed of gravity, $c_T^2$, on the B-modes of the Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-11 Marco Raveri , Carlo Baccigalupi , Alessandra Silvestri , Shuang-Yong Zhou

We reconsider the enhancement of primordial gravitational waves that arises from a quantum gravitational model of inflation. A distinctive feature of this model is that the end of inflation witnesses a brief phase during which the Hubble…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Maria G. Romania , N. C. Tsamis , R. P. Woodard

With the planning of new ambitious gravitational wave (GW) observatories, fully controlled laboratory experiments on dynamic gravitation become more and more important. Such new experiments can provide new insights in potential dynamic…

In 2022 China Space Station (CSS) will be equipped with atomic clocks and optical clocks with stabilities of $2 \times 10^{-16}$ and $8 \times 10^{-18}$, respectively, which provides an excellent opportunity to test gravitational redshift…

Instrumentation and Methods for Astrophysics · Physics 2022-04-27 Wenbin Shen , Pengfei Zhang , Ziyu Shen , Rui Xu , Xiao Sun , Mostafa Ashry , Abdelrahim Ruby , Wei Xu , Kuangchao Wu , Yifan Wu , An Ning , Lei Wang , Lihong Li , Chenghui Cai

Within this decade gravitational wave detection will open a new observational window on the Universe. Advanced ground based interferometers covering the kHz frequency range will be online by 2016, and it is foreseeable the announcement of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Alberto Sesana

The Minimal Supersymmetric SO(10) GUT has developed into a fully realistic theory in which not only are the gauge couplings unified but the known fermion spectrum and mixing matrices could fit accurately using the latitude introduced by…

High Energy Physics - Phenomenology · Physics 2015-11-24 Charanjit S. Aulakh

We update predictions for the gravitational wave (GW) signal from a strongly supercooled phase transition in an illustrative classically conformal U(1)$_{B-L}$ model. We implement $\propto \gamma^2$ scaling of the friction on the bubble…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-25 John Ellis , Marek Lewicki , Ville Vaskonen

This report is a literature review of significant and successful tests of general relativity [GR]. The GR predicted value for the perihelion advance of Mercury was Deltaf = 43.03 arcsec century^-1 and fit well with observation, being the…

General Relativity and Quantum Cosmology · Physics 2017-05-15 Estelle Asmodelle

Granular ball computing (GBC), as an efficient, robust, and scalable learning method, has become a popular research topic of granular computing. GBC includes two stages: granular ball generation (GBG) and multi-granularity learning based on…

Machine Learning · Computer Science 2025-04-10 Qin Xie , Qinghua Zhang , Shuyin Xia , Fan Zhao , Chengying Wu , Guoyin Wang , Weiping Ding

The Venusian surface has been studied by measuring radar reflections and thermal radio emission over a wide spectral region of several centimeters to meter wavelengths from the Earth-based as well as orbiter platforms. The radiometric…

Earth and Planetary Astrophysics · Physics 2017-09-28 Nithin Mohan , Subhashis Roy , Govind Swarup , Divya Oberoi , Niruj Mohan Ramanujam , Suresh Raju C , Anil Bhardwaj

The Hubble constant ($H_0$) measures the current expansion rate of the Universe, and plays a fundamental role in cosmology. Tremendous effort has been dedicated over the past decades to measure $H_0$. Notably, Planck cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-02 Kenta Hotokezaka , Ehud Nakar , Ore Gottlieb , Samaya Nissanke , Kento Masuda , Gregg Hallinan , Kunal P. Mooley , Adam. T. Deller