eROSITA Archives

November 8, 2024November 8, 2024 by Matt Williams

eROSITA All-Sky Survey Takes the Local Hot Bubble’s Temperature

3D model of the solar neighbourhood. The colour bar represents the temperature of the LHB. Credit ©: Michael Yeung/MPE

About half a century ago, astronomers theorized that the Solar System is situated in a low-density hot gas environment. This hot gas emits soft X-rays that displace the dust in the local interstellar medium (ISM), creating what is known as the Local Hot Bubble (LHB). This theory arose to explain the ubiquitous soft X-ray background (below 0.2 keV) and the lack of dust in our cosmic neighborhood. This theory has faced some challenges over the years, including the discovery that solar wind and neutral atoms interact with the heliosphere, leading to similar emissions of soft X-rays.

Thanks to new research by an international team of scientists led by the Max Planck Institute for Extraterrestrial Physics (MPE), we now have a 3D model of the hot gas in the Solar System’s neighborhood. Using data obtained by the eROSITA All-Sky Survey (eRASS1), they detected large-scale temperature differences in the LHBT that indicate that the LHB must exist, and both it and solar wind interaction contribute to the soft X-ray background. They also revealed an interstellar tunnel that could possibly link the LHB to a larger “superbubble.”

February 3, 2023February 3, 2023 by Evan Gough

Hungry Black Hole was Already Feasting 800 Million Years After the Big Bang

Artist view of an active supermassive black hole. Credit: ESO/L. Calçada

Black holes swallow everything—including light—which explains why we can’t see them. But we can observe their immediate surroundings and learn about them. And when they’re on a feeding binge, their surroundings become even more luminous and observable.

This increased luminosity allowed astronomers to find a black hole that was feasting on material only 800 million years after the Universe began.

May 12, 2022May 12, 2022 by Nancy Atkinson

Astronomers Finally Catch a Nova Detonating on a White Dwarf as it's Happening

Artist impression of an exploding White Dwarf. Credit: University of Tubigen.

On July 7, 2020, the X-ray instrument eROSITA captured an astronomical event that – until then – had only been theorized and never seen. It saw the detonation of a nova on a white dwarf star, which produced a so-called fireball explosion of X-rays.

“It was to some extent a fortunate coincidence, really,” said Ole König from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), who led the team of scientists who have published a new paper on the discovery. “These X-ray flashes last only a few hours and are almost impossible to predict, but the observational instrument must be pointed directly at the explosion at exactly the right time.”

March 8, 2022March 8, 2022 by Evan Gough

Germany’s Space Agency Cancels all its Projects With Russia. They Even Turned off an Instrument on a Russian Space Telescope

This image is an artist's illustration of the Spektr-RG satellite. Germany shut down the eROSITA instrument in response to Russia's invasion of Ukraine. Image Credit:By DLR German Aerospace Center - https://www.flickr.com/photos/dlr_de/48092069898/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=87145461

Germany is flexing its muscles.

The German government recently announced a massive increase in military spending to counter Russian military action in Europe. The German Aerospace Center (DLR) has cancelled its bilateral cooperation with Russia following that move. It looks like the Spektr-RG space telescope, a joint mission between Russia and Germany, is the first casualty of the cancelled partnership.

March 19, 2021March 19, 2021 by Matthew Cimone

An All-Sky X-Ray Survey Finds the Biggest Supernova Remnant Ever Seen

Composite Image of radio and x-ray observations of the Hoinga Supernova Remnant Credit: eROSITA/MPE (X-ray), CHIPASS/SPASS/N. Hurley-Walker, ICRAR-Curtin (Radio)

Our sky is missing supernovas. Stars live for millions or billions of years. But given the sheer number of stars in the Milky Way, we should still expect these cataclysmic stellar deaths every 30-50 years. Few of those explosions will be within naked-eye-range of Earth. Nova is from the Latin meaning “new”. Over the last 2000 years, humans have seen about seven “new” stars appear in the sky – some bright enough to be seen during the day – until they faded after the initial explosion. While we haven’t seen a new star appear in the sky for over 400 years, we can see the aftermath with telescopes – supernova remnants (SNRs) – the hot expanding gases of stellar explosions. SNRs are visible up to a 150,000 years before fading into the Galaxy. So, doing the math, there should be about 1200 visible SNRs in our sky but we’ve only managed to find about 300. That was until “Hoinga” was recently discovered. Named after the hometown of first author Scientist Werner Becker, whose research team found the SNR using the eROSITA All-Sky X-ray survey, Hoinga is one of the largest SNRs ever seen.