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Jellyfish galaxies

Galaxies that are being stripped of their gas can sometimes be recognized from their optical appearance. Extreme examples of stripped galaxies are the so-called ``jellyfish galaxies'', that exhibit tentacles of debris material with a characteristic jellyfish morphology. We have conducted the first systematic search for galaxies that are being stripped of their gas at low-z (z=0.04-0.07) in different environments (Poggianti -incl. Jaffe- et al. 2016). A visual search lead to the identification of over 400 jellyfish candidates: 344 candidates in 71 galaxy clusters of the OMEGAWINGS+WINGS sample and 75 candidates in groups and lower mass structures in the PM2GC sample.

We have an ongoing large programme (PI. Poggianti) to study 114 of jellyfish galaxies (and a few non-stripped galaxies) with MUSE/VLT. The program, called GASP (Dissecting GAs Stripping Phenomena in galaxies with MUSE), started taking data in October 2015. GASP's main aim is to understand how, when and why gas is removed from galaxies in different environments. The MUSE data is revealing great amounts of detail, as can be appreciated in the images below that separate the stellar light (white) from the ionized gas (red, Halpha).

Thanks to the unique capabilities of MUSE, GASP is accumulating many interesting results that are being published in a series of papers:

  • GASP I. Gas Stripping Phenomena in Galaxies with MUSE (Poggianti et al. 2017)
  • GASP II. A MUSE View of Extreme Ram-Pressure Stripping along the Line of Sight: Kinematics of the Jellyfish Galaxy JO201 (Bellhouse, Jaffe et al. 2017)
  • GASP III. JO36: a case of multiple environmental effects at play? (Fritz et al. 2017)
  • GASP IV. A Muse View of Extreme Ram-pressure-stripping in the Plane of the Sky: The Case of Jellyfish Galaxy JO204 (Gullieuszik et al. 2017)
  • Ram-pressure feeding of supermassive black holes (Poggianti, Jaffe et al. 2017, Nature)
  • A Hoag's jellyfish: Ram-pressure stripping of a ring galaxy in a massive cluster (Moretti et al. submitted)
  • GASP VII. Evidence for gas accretion in an isolated nearby galaxy (Vulcani et al. submitted)
  • GASP VIII: Capturing the birth of a Tidal Dwarf Galaxy in an merging system at ~0.05 (Vulcani et al. 2017)

  • In addition to the publications, we are gathering many interesting specimens for the GASP aquarium, where you can interactivelly explore the jellyufish galaxies in 3D or walk into them using a VR headset.

    You may see recent press releases about GASP: in the Outreach section, and below, you can see me posing with MUSE the first time we met: