A Curious Cosmic Collision

9 December 2015. New images from ESO’s Very Large Telescope at the Paranal Observatory show the spectacular aftermath of a 360 million year old cosmic collision in great detail. Among the debris is a rare and mysterious young dwarf galaxy that was observed during the first science verification run of the integral field spectrograph MUSE.
A Curious Cosmic Collision

The surroundings of the interacting galaxy NGC 5291 (annotated).

The galaxy NGC 5291N is providing astronomers with an excellent opportunity to learn more about similar galaxies that are expected to be common in the early Universe, but are normally too faint and distant to be observed by current telescopes. The MUSE observations revealed unexpected oxygen and hydrogen emission lines in the outskirts of NGC 5291N.

“The ability to detect and measure such faint gas emission in spectra is unique to MUSE at the VLT”, says Peter Weilbacher from the Leibniz Institute for Astrophysics Potsdam and co-investigator of the MUSE science verification program.

The Multi Unit Spectroscopic Explorer (MUSE) is a integral field 3D-spectrograph at the Very Large Telescope (VLT) of the European Southern Observatory at Paranal (Chile). Integral field spectrography collects a spectrum at every point on the sky, providing a powerful three-dimensional view of the target. interests of AIP astronomers are the spectroscopic analyses of individual objects in nearby galaxies and to study galaxy mergers. AIP developed the data reduction pipeline, has designed and built the MUSE calibration unit, and performed acceptance tests.


(Click picture to enlarge)

The full science release, more information, images and videos are published on the ESO website:

Caption: The new VLT images also show the elliptical galaxy NGC 5291, a hazy, golden oval dominating the centre of this image. It is located nearly 200 million light-years away in the constellation of Centaurus (The Centaur). Over 360 million years ago, NGC 5291 was involved in a dramatic and violent collision as another galaxy travelling at immense speeds barrelled into its core. The cosmic crash ejected huge streams of gas into nearby space, which later coalesced into a ring formation around NGC 5291. Over time, material in this ring gathered and collapsed into dozens of star-forming regions and several dwarf galaxies, revealed as pale blue and white regions scattered around NGC 5291 in this new image from the FORS instrument, mounted on the VLT. The most massive and luminous clump of material, to the right of NGC 5291, is the dwarf galaxy NGC 5291N. NGC 5291 is currently also interacting more gently with MCG-05-33-005 — or the Seashell Galaxy — the unusual comma-shaped galaxy appearing to leech off NGC 5291’s luminous core. (Credit: ESO)

Publication: This research was presented in a paper entitled “Ionization processes in a local analogue of distant clumpy galaxies: VLT MUSE IFU spectroscopy and FORS deep images of the TDG NGC 5291N”, by J. Fensch et al., to appear in the journal Astronomy & Astrophysics.

The team is composed of J. Fensch (Laboratoire AIM Paris-Saclay, CEA/IRFU/SAp, Universite Paris Diderot, Gif-sur-Yvette, France [CEA]), P.-A. Duc (CEA) , P. M. Weilbacher (Leibniz-Institut für Astrophysik, Potsdam, Germany), M. Boquien (University of Cambridge, United Kingdon; Universidad de Antofagasta, Antofagasta, Chile) and E. Zackrisson (Uppsala University, Uppsala, Sweden).