Skip to main content

TAILS OF IONISED GAS IN NGC 4569

Image: The colour image of the galaxy NGC 4569 in the Virgo cluster, obtained with MegaCam at the CFHT. The red filaments at the right of the galaxy show the ionised gas removed by ram pressure. This is about 95% of the gas reservoir of the galaxy needed to feed the formation of new stars  Credit: CFHT/Coelum

Messier 90 (also known as M90 and NGC 4569) is a member of the Virgo cluster and one of its largest and brightest spiral galaxies, about 60 million light-years away.

The environment plays a fundamental role in galaxy evolution. In fact, as a consequence of the galaxy's interaction with the intracluster medium in the Virgo Cluster, the galaxy NGC 4569 has lost much of its interstellar medium.

In the paper (Boselli et al. 2013, A&A) the authors analyze the image of NGC 4569 obtained with MegaCam at the CFHT and reveal the presence of a long tails of diffuse ionised gas without any associated stellar component extending from the disc of the galaxy up to ~ 80 kpc. This tail is referred to as ram-pressure stripping. The image also shows a prominent 8 kpc spur of ionised gas associated to the nucleus that spectroscopic data identify as an outflow.


Image: NGC 4569. Credit: NOAO/AURA/NSF.
The gas is ionised within the tail during the stripping process. The lack of star forming regions suggests that mechanisms other than photoionisation are responsible for the excitation of the gas (shocks, heat conduction, magneto hydrodynamic waves).

This analysis indicates that ram pressure stripping is efficient in massive (Mstar ~ 30 billion Msun) galaxies located in intermediate mass (~1014 Msun) clusters under formation.

The authors conclude that ram pressure stripping, rather than starvation through nuclear feedback, can be the dominant mechanism responsible for the quenching of the star formation activity of galaxies in high density environments.



Etichette:

Comments

Post a Comment

Popular posts from this blog

A Sapphire Super-Earth

Twenty-one light years away, in the constellation Cassiopeia, a planet by the name of HD219134 b orbits its star with a year that is just three days long. With a mass almost five times that of Earth, it is what is known as a super-Earth. Unlike our planet, however, these super-Earths were formed at high temperatures close to their host star and contain high quantities of calcium, aluminum and their oxides – including sapphire and ruby. HD219134 b is one of three candidates likely to belong to a new, exotic class of exoplanets. These objects are completely different from the majority of Earth-like planets. They have 10 to 20 percent lower densities than Earth. Researchers looked at different scenarios to explain the observed densities. For example, a thick atmosphere could lead to a lower overall density. But two of the exoplanets studied, 55 Cancri e and WASP-47 e, orbit their star so closely that their surface temperature is almost 3,000 degrees and they would have lost this ...
Post a Comment
Read more

CONTAMINATION BY SUPERNOVAE IN GLOBULAR CLUSTERS

Credit: ALMA (ESO/NAOJ/NRAO)/Alexandra Angelich (NRAO/AUI/NSF) Only a small amount of the supernovae products remains trapped within globular clusters and this "catch" only occurs in the most massive cases (mass cluster ≥ 10^6 solar masses).
Post a Comment
Read more

ORBITAL PERIODS OF THE PLANETS

For orbital period generally we refer to the sidereal period, that is the temporal cycle that it takes an object to make a full orbit, relative to the stars. This is the orbital period in an inertial (non-rotating) frame of reference (365,25 days for the earth).
Post a Comment
Read more