Related papers: Hubble Telescope 30 Years in Orbit: Personal Refle…

Full sky coverage with 30-40 meter-class telescopes is essential to answer fundamental questions in Astrophysics, Cosmology, and Physics, such as the composition of the Universe and the formation of the first stars and supermassive black…

Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host…

The planned NASA Habitable Worlds Observatory (HWO) flagship mission aims to image and spectroscopically characterise 25 Earth-size planets in the habitable zones of their stars. However, one giant planet in the habitable zone can ruin your…

The biggest uncertainty in determining microlensing parameters comes from the blending of source star images because the current experiments are being carried out toward very dense star fields: the Galactic bulge and Magellanic Clouds. The…

We report the outcome of a 3-day workshop on the Hubble constant (H_0) that took place during February 6-8 2012 at the Kavli Institute for Particle Astrophysics and Cosmology, on the campus of Stanford University. The participants met to…

The Hubble constant can be constrained using the time delays between multiple images of gravitationally lensed sources. In some notable cases, typical lensing analyses assuming isothermal galaxy density profiles produce low values for the…

Fundamental changes are taking place in the way we do astronomy. In twenty years time, it is likely that most astronomers will never go near a cutting-edge telescope, which will be much more efficiently operated in service mode. They will…

Strong gravitational lensing has been a powerful probe of cosmological models and gravity. To date, constraints in either domain have been obtained separately. We propose a new methodology through which the cosmological model, specifically…

Recently different cosmological measurements have shown a tension in the value of the Hubble constant, $H_0$. Assuming the $\Lambda$CDM model, the Planck satellite mission has inferred the Hubble constant from the cosmic microwave…

Time delays in strong gravitational lensing systems possess significant complementarity with distance measurements to determine the dark energy equation of state, as well as the matter density and Hubble constant. Time delays are most…

Since its launch in 1990, HST has played a leading role in optical studies of isolated neutron stars, both radio-loud pulsars and radio-silent ones, paving the way to follow-up observations performed with 8m-class telescopes, like the VLT,…

October 1957, and the successful launch of Sputnik 1 into Earth orbit, marked the dawn of the Space Age. The first of the 'fellow travellers' - humanity's first artificial satellite - orbited for a mere three months before re-entering the…

The aim is to document in some detail the last 35 years of meridian circles, a type of instrument with a fundamental role in astronomy for a very long time, and to do so while witnesses are still alive and can contribute. This is about…

Observations with the Hubble Space Telescope (HST), conducted since 1990, now offer an unprecedented glimpse into fast astrophysical shocks in the young remnant of supernova 1987A. Comparing observations taken in 2010 using the refurbished…

Strong gravitationally lensed supernovae (SNe) are a powerful probe for cosmology and stellar physics. The relative time delays between lensed SN images provide an independent way of measuring a fundamental cosmological parameter -- the…

We present a simultaneous analysis of 10 galaxy lenses having time-delay measurements. For each lens we derive a detailed free-form mass map, with uncertainties, and with the additional requirement of a shared value of the Hubble parameter…

For the quadruple gravitational lens PG 1115+080, we combine recent measurements of the time delays with new lens models to determine the Hubble constant H_0. We explore the effects of systematic uncertainties in the lens models on the…

It has been proposed that the gravitational constant $G$ abruptly decreased around 130 Myr ago, making Type Ia supernovae (SNe) in the Hubble flow intrinsically brighter than those in host galaxies with Cepheid distances. This would make…

A unique test of general relativity is possible with the space radio telescope RadioAstron. The ultra-stable on-board hydrogen maser frequency standard and the highly eccentric orbit make RadioAstron an ideal instrument for probing the…

The Origins Space Telescope (OST) will transform our understanding of the Universe, from formation of the earliest galaxies to the creation of habitable worlds. OST's Mission Concept 1, the subject of this report, features a cold (4 K)…