Optically similar elliptical galaxies have an enormous range of X-ray luminosities. We show that this range can be attributed to large variations in the dark halo mass determined from X-ray observations. The Mvir K-band luminosity of ellipticals varies with virial mass, , but with considerable scatter, probably due to 0.750.22 LK ∝ Mvir the stochastic incidence of massive satellite galaxies that merge by dynamical friction to form group-centered ellipticals. Both the observed X-ray luminosity and are sufficiently sensitive to the virial 2.4 1.6 L X vir X ∝ M L /LK ∝ Mvir mass to explain the wide variation observed in among galaxies of similar . The central galaxy supernova L L X K energy per particle of diffuse gas increases dramatically with decreasing virial mass, and elliptical galaxies with the lowest X-ray luminosities (and ) are easily explained by supernova-driven outflows.
Mathews W.G., Brighenti F., Faltenbacher A., Buote D.A., Humphrey P.J., Gastaldello F., et al. (2006). Large Scatter in X-Ray Emission among Elliptical Galaxies: Correlations with Mass of Host Halo. THE ASTROPHYSICAL JOURNAL LETTERS, 652 (1), L17-L20 [10.1086/509915].
Large Scatter in X-Ray Emission among Elliptical Galaxies: Correlations with Mass of Host Halo
BRIGHENTI, FABRIZIO;
2006
Abstract
Optically similar elliptical galaxies have an enormous range of X-ray luminosities. We show that this range can be attributed to large variations in the dark halo mass determined from X-ray observations. The Mvir K-band luminosity of ellipticals varies with virial mass, , but with considerable scatter, probably due to 0.750.22 LK ∝ Mvir the stochastic incidence of massive satellite galaxies that merge by dynamical friction to form group-centered ellipticals. Both the observed X-ray luminosity and are sufficiently sensitive to the virial 2.4 1.6 L X vir X ∝ M L /LK ∝ Mvir mass to explain the wide variation observed in among galaxies of similar . The central galaxy supernova L L X K energy per particle of diffuse gas increases dramatically with decreasing virial mass, and elliptical galaxies with the lowest X-ray luminosities (and ) are easily explained by supernova-driven outflows.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
