NGC 4839
Credit: X-ray: Chandra: NASA/SAO/Univ. of Alabama/M. S. Mirakhor et al.; XMM: ESA/XMM-Newton;
Optical: SDSS; Image processing: N. Wolk

A group of galaxies is plunging into the Coma galaxy cluster and leaving behind an enormous tail of superheated gas. Astronomers have confirmed this is the longest known tail behind a galaxy group and used it to gain a deeper understanding of how galaxy clusters – some of the largest structures in the universe – grow to their enormous sizes.

NGC 253
Credit: X-ray: NASA/CXC/The Ohio State Univ/S. Lopez et al.; H-alpha and Optical: NSF/NOIRLab/AURA/KPNO/CTIO; Infrared: NASA/JPL-Caltech/Spitzer/D. Dale et al; Full Field Optical: ESO/La Silla Observatory.

On Earth, wind can transport particles of dust and debris across the planet, with sand from the Sahara ending up in the Caribbean or volcanic ash from Iceland being deposited in Greenland. Wind can also have a big impact on the ecology and environment of a galaxy, just like on Earth, but on much larger and more dramatic scales.

A new study using NASA's Chandra X-ray Observatory shows the effects of powerful winds launched from the center of a nearby galaxy, NGC 253, located 11.4 million light-years from Earth. This galactic wind is composed of gas with temperatures of millions of degrees that glows in X-rays. An amount of hot gas equivalent to about two million Earth masses blows away from the galaxy's center every year.

NGC 253 is a spiral galaxy, making it similar to our Milky Way. However, stars are forming in NGC 253 about two to three times more quickly than in our home galaxy. Some of these young stars are massive and generate a wind by ferociously blowing gas from their surfaces. Even more powerful winds are unleashed when, later in their relatively short lives, these stars explode as supernovae, and hurl waves of material out into space.

R Aquarii, All Wavelengths

Credit: X-ray: NASA/CXC/SAO/R. Montez et al.; Optical: Data: NASA/ESA/STScI, Enhanced processing by Judy Schmidt (CC BY-NC-SA). X-ray/Optical composite processing by CXC/N. Wolk & K.Arcand; Sonification: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)

The system called R Aquarii unfolds dramatically through the eyes of NASA’s Chandra X-ray Observatory (purple) and Hubble Space Telescope (red and blue). The spectacular structures outlined in the Hubble data are old notes, or in other words, evidence from outbursts generated by a pair of stars buried at the center of the image. X-rays from Chandra reveal how a jet from one of these stars — a cool stellar ember known as a white dwarf — is banging into the material surrounding it. This high-powered flow creates shock waves, similar to sonic booms from planes that move faster than the speed of sound. The other player with the white dwarf in this interstellar duet is a red giant star. As they orbit each other, the white dwarf pulls material from the red giant onto its surface. Over time, enough of this material accumulates and triggers an explosion. Astronomers have seen such outbursts over recent decades and this dynamic chorus will likely go on for millennia to come.

Valentina Missaglia

We are happy to welcome Valentina Missaglia as a guest blogger. She is the first author of the paper that is the subject of our latest press release. She is currently a postdoctoral researcher at the Institute of Astrophysics — FORTH in Heraklion (Crete) in the SMILE (“Search for Milli-LEnses”) group, recently funded by an ERC grant, that aims at investigating the nature of dark matter through observations of gravitational lenses on milli-arcsecond scales. Valentina earned her Ph.D. from the University of Turin (Italy) and her research focuses on radio and X-ray emission from radio-loud active galactic nuclei (which contain supermassive black holes that are rapidly pulling in material, producing intense radio waves) and how these sources interact with the surrounding medium. Before starting her Ph.D. in 2019, Valentina was a visiting student at the Center of Astrophysics | Harvard & Smithsonian, where she collaborated with Dr. Ralph Kraft on observations of galaxy clusters performed with NASA’s Chandra X-ray Observatory.

Looking at the night sky with the naked eye, we can only see an infinitesimal part of what the Universe contains, and the largest part cannot even be “seen”. Radio wavelengths have gifted us some of the most fascinating astronomical sources: radio-loud active galactic nuclei in the centers of galaxies, which can produce jets that extend way farther out from the optical galaxy itself.

The most powerful radio sources in the northern hemisphere are listed in a well- studied catalog, the Third Cambridge Catalog (3C), which contains the source we investigated with multiwavelength observations: 3C 297. This source appeared very intriguing in observations performed with Chandra in 2016. Therefore, we requested more time to better investigate features that we uncovered thanks to this first short observation, such as hot, X-ray emitting gas around our source.

Tycho's Supernova Remnant
Credit: X-ray (IXPE: NASA/ASI/MSFC/INAF/R. Ferrazzoli, et al.), (Chandra: NASA/CXC/RIKEN & GSFC/T. Sato et al.) Optical: DSS, Image processing: NASA/CXC/SAO/K. Arcand, L. Frattare & N. Wolk

This image provides a new look at the Tycho supernova remnant, named for Danish astronomer Tycho Brahe who noticed the bright glow of this new “star” in the constellation Cassiopeia more than 450 years ago. Astronomers used NASA’S Imaging X-ray Polarimetry Explorer (IXPE) to study polarized light from Tycho, the debris from an exploded star, as described in IXPE’s latest press release. IXPE revealed, for the first time, the geometry of the magnetic fields close to the supernova’s blast wave, which is still propagating from the initial explosion and forms a boundary around the ejected material. Understanding the magnetic field geometry allows scientists to further investigate how particles are accelerated there.

In this composite image, data from IXPE (dark purple and white) have been combined with those from NASA’s Chandra X-ray Observatory (red and blue), which were overlaid with the stars in the field of view seen by the Digitized Sky Survey.