A partially occulting MACHO-microlensing event in the Twin Quasar Q0957+561

TL;DR

This paper analyzes a unique microlensing event in the Twin Quasar Q0957+561, revealing a primordial gas cloud acting as a lens and occulting the quasar's accretion disk, supporting gravitational hydrodynamics theory.

Contribution

It presents a detailed model of a microlensing event caused by a primordial gas cloud within the Galaxy, combining lensing and occultation effects for the first time.

Findings

The lens is a 0.5 Earth-mass primordial gas cloud.

The cloud is 1.4 Solar radii and 17 K, consistent with gravitational hydrodynamics.

Partial occultation explains the doubly-peaked microlensing event.

Abstract

A doubly-peaked quasar microlensing event in the lensed Twin Quasar Q0957+561 A,B (Colley and Schild 2003) is analysed within several lensing models. In the most realistic model a lens resolves in image B the ellipse shaped, bright inner rim of the quasar's accretion disk, intersecting it twice. This lens weighs 0.5 Earth mass and is located inside the Galaxy, at 3 kpc distance. During the passing, it partially occults the source, which allows to describe it as a primordial gas cloud of 1.4 Solar radius and 17 K temperature, in accordance with the theory of Gravitational Hydrodynamics. Lensing by such objects against the Magellanic Clouds and Galactic centre will also lead to occultation dips.