GalevNB: a conversion fromN-body simulations to observations

Abstract

We present GalevNB (Galev for N-body simulations), an utility that converts fundamental stellar properties of N-body simulations into observational properties using the GALEV (GAlaxy EVolutionary synthesis models) package, and thus allowing direct comparisons between observations and N-body simulations. It works by converting fundamental stellar properties, such as stellar mass, temperature, luminosity and metallicity into observational magnitudes for a variety of filters of mainstream instruments/telescopes, such as HST, ESO, SDSS, 2MASS, etc.), and into spectra that spans from far-UV (90 Å) to near-IR (160 µm). As an application, we use GalevNB to investigate the secular evolution of spectral energy distribution (SED) and color-magnitude diagram (CMD) of a simulated star cluster over a few hundred million years. With the results given by GalevNB we discover an UV-excess in the SED of the cluster over the whole simulation time. We also identify four candidates that contribute to the FUV peak, core helium burning stars, thermal pulsing asymptotic giant branch (TPAGB) stars, white dwarfs and naked helium stars.

The dynamical origin of multiple populations in intermediate-age clusters in the Magellanic Clouds

“…In addition to these standard recipes the natal kicks of neutron stars have been updated (Hobbs et al 2005) in the treatment of velocity kicks for neutron stars (NSs) and black holes (BHs) when they form after supernova explosions, and employing a fallback scenario according to Belczynski et al (2002) for the formation of a certain mass range of stellar BHs (for more details see Wang et al 2016). Note that spectral synthesis routines (GALEV) are now coupled to our NBODY code, which will allow us also to present spectra and CMDs of our simulated star clusters in every desired waveband (Pang et al 2016). …”

The long-term evolution of main-sequence binaries in DRAGON simulations

“…To investigate the radial color difference in the segregated DRAGON clusters, we derived the integrated color F 330W − F 814W (HST filters) of two modeled clusters via GalevNB (Pang et al 2016) and show the color value in each annulus in Figure 15. A color gradient is found in all star and binary samples of D1-R7-IMF93, and only in all star samples of D2-R7-IMF01.…”

COCOA Code for Creating Mock Observations of Star Cluster Models

“…COCOA can be used together with the publicly available GALEVNB code 4 Pang et al 2016) to obtain magnitudes in different photometric filters for stars in simulation snapshots. The GALEVNB code can provide magnitudes for stars in snapshots of numerical simulations in a variety of different filters for various wavelengths.…”

“…The GALEVNB code can provide magnitudes for stars in snapshots of numerical simulations in a variety of different filters for various wavelengths. Using stellar properties such as mass, temperature, luminosity and metallicity, GALEVNB can generate a spectra that covers far UV to far IR wavelengths with a resolution of 20 Å (Pang et al 2016). To obtain magnitudes in different filters, GALEVNB convolves the spectra with the filter response functions and applies selected zero-points corrections.…”