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

Fermi Bubbles

Image: A giant gamma-ray structure was discovered in 2010 by processing Fermi all-sky data at energies from 1 to 10 billion electron volts, shown here. The dumbbell-shaped feature (center) emerges from the galactic center and extends 50 degrees north and south from the plane of the Milky Way, spanning the sky from the constellation Virgo to the constellation Grus. Credits: NASA/DOE/Fermi LAT/D. Finkbeiner et al. At a time when our earliest human ancestors mastered walking upright the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.
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

SUPER-EDDINGTON ACCRETION IN ACTIVE GALACTIC NUCLEI

Supermassive black holes at the cores of galaxies blast radiation and ultra-fast winds outward, as illustrated in this artist's conception. Credit: NASA/JPL-Caltech Broad emission lines are a hallmark feature of type 1 active galactic nuclei (AGNs) and quasars. Many basic properties of the broad-line region (BLR), such as its basic geometry, dynamics, and physical connection to the accretion disk around the supermassive black hole (BH), remain illdefined. AGN spectra exhibit both tremendous diversity as well as discernable patterns of systematic regularity.
Post a Comment
Read more