Images and videos

A characteristic SIGO environments. The SIGO is located in the center of each panel with a zoom-in to the center region. Left panel: projected overdensities of a characteristic SIGO environments. The Dark Matter halos are identified by the black circles. Right panel: a slice of the velocity field is also shown for the same region as in the left panel. See for more details Chiou et al. (2021).


SIGOs' map density contrast at z = 20. Here the color scale represents the fluctuation of SIGOs abundances resulting from the variations in stream velocity on large scales. See for more details Lake et al. (2021).

The gas density field in a simulation box with 2σ stream velocity effect. SIGOs are marked with Xs. Note here that SIGOs trace gas and halo abundances on these scales, but they are off-set from the Dark Matter halos. See for more details Lake et al. (2022).


If SIGOs are indeed connected to globular clusters, we can connect the abundance of SIGOs to the abundance of globular clusters and therefore possibly to the abundance of Black-hole binary merger events. As a result, in Lake et al. (2021) we suggested an anisotropy in the distribution of BBH merger events derived from the variation in SIGO abundances on the sky. The Figure shows a sky-map of integrated BBH merger abundances in globular clusters, to a distance of 675 Mpc. Numbers are given in mergers per steradian per year, assuming a merger rate of 10-8 per year per cluster.

The creation of a GC-like system at high redshift (z=20). This SIGO is labelled GC-like in the figure, for globular cluster-like candidate. This SIGO, is accreted by a nearby halo (the gas component of which is shown in the movie, the right branch of the plot, with a very low baryon fraction). This accretion produces a more massive merged object, containing the SIGO in its substructure. The final configuration resembles a globular cluster-like candidate. See for more details Lake et al. (2022).


The Growth of a SIGO: here we show the time evolution of a single SIGO. This SIGO increases its mass by nearly a factor of 10 between its formation (z=24.5) and the final, accreting gas from its surroundings with a similar baryon fraction to the SIGO itself and thereby maintaining its baryon fraction over time. See for more details Lake et al. (2022).

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