Skip to main content

RELATION BETWEEN TIDAL DISRUPTION EVENTS AND HOST GALAXIES

Image: Artistic illustration of a black hole divouring a star. Credit: NASA/Goddard Space Flight Center/CI Lab
 
A tidal disruption event occurs when a star gets close enough to a supermassive black hole's event horizon and is pulled apart by the black hole's tidal forces.
In a recent paper (French, Arcavi & Zabludoff, 2016 ApJL) the authors show that the tidal disruption events occur more frequently in host galaxies with strong Balmer line absorption. This feature indicates low levels of current star formation.





The Balmer lines in atomic physics, is the designation of one of a set of six named series describing the spectral line emissions of the hydrogen atom. The Balmer series is characterized by the electron transitioning from n > 2 to n = 2, where n refers to the radial quantum number or principal quantum number of the electron.

In the simplified Rutherford Bohr model of the hydrogen atom, the Balmer lines result from an electron jump between the second energy level closest to the nucleus, and those levels more distant. Shown here is a photon emission. (https://en.wikipedia.org/wiki/Balmer_series)





The connection tidal-disruption/host-galaxy may be due to the fact that these host galaxies have had a recent galaxy-galaxy merger. Such event increases the possibility of formation of black-hole binaries, perturbed stellar orbits and a spatially-concentrated population of A giant stars.


Figure: Tidal disruption of a star. Credit: NASA/Goddard Space Flight Center/Swift


▪ French, Arcavi & Zabludoff (ApJL) - Tidal drisuption events prefer unusual host galaxies. (arXiv)


Etichette:

Comments

Post a Comment

Popular posts from this blog

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

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

SUPERNOVAE FROM WD-WD DIRECT COLLISIONS

Image: Supernova remnant N 63A. Credit: NASA/ESA/HEIC and The Hubble Heritage Team (STScI/AURA) Models for supernovae (SNe) related to thermonuclear explosions of white dwarfs (WDs) have been extensively studied over the last few decades, mostly focusing on single degenerate (accretion of material of a WD) and double degenerate (WD-WD merger) scenarios.
Post a Comment
Read more