Related papers: Comment on: "2005 VL1 is not Venera-2"
Samarasinha & Mueller (2013) related changes of cometary rotation to other physical parameters for four Jupiter family comets defining a parameter $X$, which is approximately constant within a factor of two irrespective of the active…
Very Long Baseline Interferometry is capable of measuring the gravitational delay caused by the Sun and planet gravitational fields. The post-Newtonian parameter $\gamma$ is now estimated with accuracy of $\sigma_{\gamma}=2\cdot 10^{-4}$…
As the gravitational wave detector network is upgraded and the sensitivity of the detectors improves, novel scientific avenues open for exploration. For example, tests of general relativity will become more accurate as smaller deviations…
Chandra observations of the Vela pulsar-wind nebula (PWN) have revealed a jet in the direction of the pulsar's proper motion, and a counter-jet in the opposite direction, embedded in diffuse nebular emission. The jet consists of a bright,…
In this paper we investigate how observational effects could possibly bias cosmological inferences from peculiar velocity measurements. Specifically, we look at how bulk flow measurements are compared with theoretical predictions. Usually…
As a comet, asteroid or planet approaches its parent star, the orbit changes shape due to the curvature of spacetime. For comets in particular, the deviation at the pericentre may noticeably change their ephemerides and affect the dynamics…
The microquasar nature of LS5039 was revealed by May 1999 VLBA+VLA observations showing a two-sided jet at milliarcsecond scales. Here we present follow-up interferometric observations carried out with the EVN and MERLIN at 5 GHz in March…
An ancient Venusian rock could constrain that planet's history, and reveal the past existence of oceans. Such samples may persist on the Moon, which lacks an atmosphere and significant geological activity. We demonstrate that if Venus'…
At Large Hadron Collider energy, the expected large multiplicities suggests the presence of collective behavior even in pp collisions. A hydrodynamical approach has been applied to estimate the expected elliptic flow measured by the…
VLTI/AMBER and VLTI/PIONIER observations of the LBV HR Car show an interferometric signature that could not possibly be explained by an extended wind, more or less symmetrically distributed around a single object. Instead, observations both…
We derive a model of dark energy which evolves with time via the scale factor. The equation of state $\omega=(1-2\alpha)/(1+2\alpha)$ is studied as a function of a parameter $\alpha$ introduced in this model. In addition to the recent…
The standard approach to test for deviations from general relativity on cosmological scales is to combine measurements of the growth rate of structure with gravitational lensing. In this study, we show that this method suffers from an…
The distance to the Vela pulsar (PSR B0833-45) has been traditionally assumed to be 500 pc. Although affected by a significant uncertainty, this value stuck to both the pulsar and the SNR. In an effort to obtain a model free distance…
KV Vel is a non-eclipsing short-period (P = 0.3571 days) close binary containing a very hot subdwarf primary (77000 K) and a cool low-mass secondary star (3400 K) that is located at the center of the planetary nebula DS 1. The changes in…
We report high-spectral resolution observations of comet 9P/Tempel 1 before, during and after the impact on 4 July 2005 UT of the Deep Impact spacecraft with the comet. These observations were obtained with the HIRES instrument on Keck 1.…
It is argued that, in models where the gravitational coupling is scale-dependent, predictions concerning weak gravitational lensing and shear are essentially similar to the ones derived from General Relativity. This is consistent with…
We argue that the so-called "Pioneer Anomaly" is related to the quantum vacuum fluctuations. Our approach is based on the hypothesis of the gravitational repulsion between matter and antimatter, what allows considering, the virtual…
We compare the cosmological kinematics obtained via our law of linearly varying deceleration parameter (LVDP) with the kinematics obtained in the {\Lambda}CDM model. We show that the LVDP model is almost indistinguishable from the…
Extrapolation of the astrometric motion of the nearby low-mass star VB 10 indicates that sometime in late December 2011 or during the first 2-3 months of 2012, the star will make a close approach to a background point source. Based on…
Stellar activity manifests differently across wavelengths, causing flux variability that can obscure planetary transits. While transit observations are typically performed in the visible and infrared bands, where stellar flux is relatively…