Science Contact MPIA

Melissa Ness
Phone: (+49|0) 6221 528-412

Public Information Officer MPIA

profile_image
Markus Pössel
Public Information Officer
Phone:(+49|0) 6221 528-261
Email:pr@...

Science Contact University of Toronto

Dustin Lang
Phone:+1 416 978-2183
Email:lang@...

Dunlap Institute for Astronomy & Astrophysics at the University of Toronto

Media Contact University of Toronto

Chris Sasaki
Communications Coordinator, Public Information Officer
Phone:+1 416 978-6613

Dunlap Institute for Astronomy & Astrophysics at the University of Toronto

Media Contact JPL/WISE

Elizabeth Landau
Media Relations Specialist
Phone:+1 818 354-6425

NASA Jet Propulsion Laboratory

Gigantic X-shaped structure throws (infrared) light on Galactic history

July 19, 2016

Two astronomers have produced the first direct images of a gigantic X-shaped distribution of stars in the center of the Milky Way. The collaboration shows the value of open science: it began when Dustin Lang (University of Toronto) tweeted an image he had recently created. From the tweet, Melissa Ness (Max Planck Institute for Astronomy) recognized the image's significance for reconstructing the history of our home galaxy. The X-shaped distribution indicates that the bulge of stars surrounding the center of the galactic disk was formed through dynamical interactions of stars, not by the merger of smaller galaxies with our own.
Figure 1: X marks the spot: This image was especially enhanced to show the X-shaped distribution around the bulge more clearly. The image shows the central 30 degrees of galactic longitude and 30 degrees of galactic latitude, and is based on data from the NASA space telescope WISE. Zoom Image
Figure 1: X marks the spot: This image was especially enhanced to show the X-shaped distribution around the bulge more clearly. The image shows the central 30 degrees of galactic longitude and 30 degrees of galactic latitude, and is based on data from the NASA space telescope WISE.

Sometimes, new science starts with a single tweet. When Dustin Lang of the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto tweeted an image of the Milky Way in May 2015, he was glad to have finished a complex project ("I don’t want to admit how long it took to summarize 150 gigapixels into this WISE [image]," his comment read). He didn't realize the tweet would kick off a new study altogether.

But when Melissa Ness of the Max Planck Institute for Astronomy saw the tweet, she recognized traces of a structure astronomers had long sought for, but never seen directly in an image: an X-shaped distribution of stars in the central region ("bulge") of the Milky Way.

Ness and Lang met in person a few weeks later at a conference and began to collaborate, processing the maps to obtain the first clear image of the giant X at the heart of our galaxy. The results have recently been published in the Astronomical Journal.

Figure 2: In this map of the central regions of the Milky Way, created by Dustin Lang from data taken with the NASA infrared space telescope WISE, the X-shaped distribution of stars in the bulge is visible. Zoom Image
Figure 2: In this map of the central regions of the Milky Way, created by Dustin Lang from data taken with the NASA infrared space telescope WISE, the X-shaped distribution of stars in the bulge is visible.

For astronomers like Ness, who are interested in the evolution of our home galaxy, the shape of the bulge is a key marker of Milky Way history. As Ness states, "If we understand the bulge we will understand the key processes that have formed and shaped our galaxy." In particular, the presence of the X shape indicates that the central bulge of stars in our Milky Way formed from dynamical interactions of our galaxy's stars and not, as an alternative model posits, from mergers of smaller galaxies with our Milky Way.

For Lang, the collaboration holds a more general lesson about open science. He says: "To me, this study is an example of the interesting, serendipitous science that can come from large data sets that are publicly available," he said. "I'm very pleased to see my WISE sky maps being used to answer questions that I didn't even know existed."

Additional information

A more complete explanation of the research and its context can be found on this background page.

Images for download

 
loading content