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.
Large Scatter in X-Ray Emission among Elliptical Galaxies: Correlations with Mass of Host Halo / Mathews W.G.; Brighenti F.; Faltenbacher A.; Buote D.A.; Humphrey P.J.; Gastaldello F.; Zappacosta L.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 652 (1):(2006), pp. 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.
