We present Hubble Space Telescope (HST ) spectroscopy of the nucleus of M31 obtained with the Space Telescope Imaging Spectrograph (STIS). Spectra that include the Ca ii infrared triplet (k ’ 85008) see only the red giant stars in the double brightness peaks P1 and P2. In contrast, spectra taken at k ’ 3600 51008 are sensitive to the tiny blue nucleus embedded in P2, the lower surface brightnes...

ABSTRACT We present a suite of high-resolution hydrodynamic simulations binaries immersed in circumbinary accretion discs (CBDs). For the first time, we investigate preferential rate as function both eccentricity eb and mass ratio qb densely sampled parameter space, finding that when compared with circular binaries, (i) ratios grow more efficiently on moderately eccentric orbits (0.0 ? 0.4), (i...

The interaction of binary black hole mergers with their environments can be studied using numerical relativity simulations. These start only a short finite time before merger, at which point appropriate initial conditions must imposed. A key task is therefore to identify the configuration that for and its environment this stage evolution. In work we study behaviour wave dark matter around equal...

We use long-run, high-resolution hydrodynamics simulations to compute the multiwavelength light curves (LCs) from thermal disk emission around accreting equal-mass supermassive black hole (BH) binaries, with a focus on revealing binary eccentricity. LCs are obtained by modeling thermodynamics an adiabatic equation of state, local blackbody cooling prescription, and corrections approximate effec...