Helene Courtois - Finding Our Place in the Universe: How We Discovered Laniakea the Milky Ways Home

Examples of galaxy morphology: elliptical (ESO 325), irregular (NGC 1427A), spiral (M83).

From the solar system to the observable universe: you are here! (Also plate 1.)

The electromagnetic spectrum.

Views of Orion, in the night sky and in 3D.

Illustration of the parallax method, after Bessel.

Representative distances in the universe.

The Milky Way, as seen by Caroline and William Herschel.

Absolute luminosity and apparent brightness.

Close-ups of the Local Universe.

Valrie de Lapparent delivering a talk on large galaxy structures, including the Great Wall, at a 2009 conference.

One of my first maps showing the Cocoon.

Polynesian navigation.

Spectral transitions in the course of a photons emission and absorption. (Also plate 2.)

Hubbles Law.

The expansion of raisin bread.

Using the Doppler effect in observational cosmology. (Also plate 3.)

Total velocity, recessional velocity, and peculiar velocity of a passenger running inside a train.

Our large-scale motion in the universe.

Enlargement of an absorption line in an elliptical galaxy.

The dynamic map constructed by the Seven Samurai in 1986 (from Alan Dressler, Voyage to the Great Attractor [New York: Alfred A. Knopf, 1994]).

View of the Siding Spring observatory in Warrumbungle National Park, New South Wales, Australia.

Obtaining spectral data with FLAIR.

What is the fate of a universe in accelerated expansion?

The main telescopes used to create our modern data sets. Left to right, top to bottom: Parkes (Australia), Green Bank (West Virginia), Mauna Kea (Hawaii), Spitzer (NASA), Hubble (NASA), Arecibo (Puerto Rico). (Also plate 4.)

Broadening of the hydrogen emission line from a spiral galaxy. (Also plate 5.)

To measure the distance of a spiral galaxy using the Tully-Fisher method, we need to observe using two types of telescope: a radio telescope and an optical telescope.

Spiral galaxies on parade. (Also plate 6.)

Different methods for estimating the distances of celestial objects.

Dynamic map created using the CF1 data set.

A representation of large-scale structures.

Our Cosmicflows-2 dynamic map of radial velocities. The arrows indicate the direction of movement. (Also plate 7.)

Equations from Yehuda Hoffmans velocity reconstruction algorithm.

The importance of the Wiener filter.

Cosmic microwave background anisotropy. The map on top shows the dipole due to our galaxys motion; removing it allows us to detect the inhomogeneities due to primordial fluctuations (bottom map).

The purpose of visualization. (Also plate 8.)

Maps summarizing the steps in our method.

Evidence of our Laniakea Supercluster through a visualization from the CF2 dataset. (Also plate 9.)

Illustration of watersheds in hydrology.

The train analogy to help clarify Laniakeas future.

A new line in our cosmic address.

Laniakea enclosed in a glass cube.

An image of Laniakea projected onto a building faade, Lyon Festival of Light, 2014. (Also plate 10.)

The cosmic web obtained through a CLUES numerical simulation.

Time-lapse produced by a constrained simulation based on CF2. Here we can see the birth and development of our corner of the universe, from left to right at the ages of 500 million years, 6 billion, and 13.8 billion years. (Also plate 11.)

Absorption of electromagnetic waves by the earths atmosphere.

First map from the Cosmicflows-3 generation. Here we can see that the cosmic flows show the other watersheds surrounding Laniakea. (Also plate 12.)

Illustration of the cosmological principle.

The sizes of the four Cosmicflows programs. (Also plate 13.)

Photos and artists impression of the telescopes of the future. Top to bottom: ASKAP (Australia), MeerKAT (South Africa), Euclid (European Space Agency).

From left to right: Daniel Pomarde, Yehuda Hoffman, Hlne Courtois, Brent Tully, Stefan Gottlber.

Family photo!