CLUES Publications

Publications retrieved from NASA ADS and sorted by publication date in reverse order

More from CLUES library at ADS

Suppression of star formation in low-mass galaxies caused by the reionization of their local neighbourhood
Dawoodbhoy, T., Shapiro, P. R., Ocvirk, P., Aubert, D., Gillet, N., Choi, J.-H., Iliev, I. T., Teyssier, R., Yepes, G., Gottlöber, S., D’Aloisio, A., Park, H., Hoffman, Y., 2018, Monthly Notices of the Royal Astronomical Society , 480, 2 , 1740
Published: October 2018
doi:10.1093/mnras/sty1945
Abstract:
Photoheating associated with reionization suppressed star formation in low-mass galaxies. Reionization was inhomogeneous, however, affecting different regions at different times. To establish the causal connection between reionization and suppression, we must take this local variation into account. We analyze the results of CoDa (`Cosmic Dawn') I, the first fully coupled radiation-hydrodynamical simulation of reionization and galaxy formation in the Local Universe, in a volume large enough to model reionization globally but with enough resolving power to follow all atomic-cooling galactic halos in that volume. For every halo identified at a given time, we find the redshift at which the surrounding IGM reionized, along with its instantaneous star formation rate (`SFR') and baryonic gas-to-dark matter ratio (M_{gas}/M_{M}). The average SFR per halo with M < 109M⊙ was steady in regions not yet reionized, but declined sharply following local reionization. For M > 1010M⊙, this SFR continued through local reionization, increasing with time, instead. For 109M⊙ < M < 1010M⊙, the SFR generally increased modestly through reionization, followed by a modest decline. In general, halo SFRs were higher for regions that reionized earlier. A similar pattern was found for M_{gas}/M_{DM}, which declined sharply following local reionization for M < 109M⊙. Local reionization time correlates with local matter overdensity, which determines the local rates of structure formation and ionizing photon consumption. The earliest patches to develop structure and reionize ultimately produced more stars than they needed to finish and maintain their own reionization, exporting their `surplus' starlight to help reionize regions that developed structure later.
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Hoffman, Y., Carlesi, E., Pomarède, D., Tully, R. B., Courtois, H. M., Gottlöber, S., Libeskind, N. I., Sorce, J. G., Yepes, G., 2018, Nature Astronomy , 2 , 680
Published: July 2018
doi:10.1038/s41550-018-0502-4
Abstract:
The local Universe provides a unique opportunity for testing cosmology and theories of structure formation. As the velocities of galaxies respond to the distribution of matter—both visible and dark—the velocity field provides structural information. Here, we present an original method for the reconstruction of the quasi-linear matter density and velocity fields from galaxy peculiar velocities and apply it to the Cosmicflows-2 database of velocites. The method consists of constructing an ensemble of cosmological simulations, constrained by the standard cosmological model and the observational data. The quasi-linear density field is the geometric mean and variance of the fully nonlinear density fields of the simulations. The main nearby clusters (Virgo, Centaurus and Coma), superclusters (Shapley and Perseus-Pisces) and voids (Dipole Repeller) are robustly reconstructed. Galaxies are born `biased` with respect to the underlying dark matter distribution. Using our quasi-linear framework, we demonstrate that the luminosity-weighted density field derived from the 2M++ redshift compilations is nonlinearly biased with respect to the matter density field. The bias diminishes in the linear regime.
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Dixon, K. L., Iliev, I. T., Gottlöber, S., Yepes, G., Knebe, A., Libeskind, N., Hoffman, Y., 2018, Monthly Notices of the Royal Astronomical Society , 477, 1 , 867
Published: June 2018
doi:10.1093/mnras/sty494
Abstract:
Observations of the Milky Way (MW), M31, and their vicinity, known as the Local Group (LG), can provide clues about the sources of reionization. We present a suite of radiative transfer simulations based on initial conditions provided by the Constrained Local UniversE Simulations (CLUES) project that are designed to recreate the Local Universe, including a realistic MW-M31 pair and a nearby Virgo. Our box size (91 Mpc) is large enough to incorporate the relevant sources of ionizing photons for the LG. We employ a range of source models, mimicking the potential effects of radiative feedback for dark matter haloes between {∼ }10^8 and 10^9 M_{⊙}. Although the LG mostly reionizes in an inside-out fashion, the final 40 per cent of its ionization shows some outside influence. For the LG satellites, we find no evidence that their redshift of reionization is related to the present-day mass of the satellite or the distance from the central galaxy. We find that fewer than 20 per cent of present-day satellites for MW and M31 have undergone any star formation prior to the end of global reionization. Approximately 5 per cent of these satellites could be classified as fossils, meaning the majority of star formation occurred at these early times. The more massive satellites have more cumulative star formation prior to the end of global reionization, but the scatter is significant, especially at the low-mass end. Present-day mass and distance from the central galaxy are poor predictors for the presence of ancient stellar populations in satellite galaxies.
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Aubert, D., Deparis, N., Ocvirk, P., Shapiro, P. R., Iliev, I. T., Yepes, G., Gottlöber, S., Hoffman, Y., Teyssier, R., 2018, The Astrophysical Journal , 856, 2 , L22
Published: April 2018
doi:10.3847/2041-8213/aab14d
Abstract:
Today’s galaxies experienced cosmic reionization at different times in different locations. For the first time, reionization (50% ionized) redshifts, z R , at the location of their progenitors are derived from new, fully coupled radiation-hydrodynamics simulation of galaxy formation and reionization at z > 6, matched to N-body simulation to z = 0. Constrained initial conditions were chosen to form the well-known structures of the local universe, including the Local Group and Virgo, in a (91 Mpc)3 volume large enough to model both global and local reionization. Reionization simulation CoDa I-AMR, by CPU-GPU code EMMA, used (2048)3 particles and (2048)3 initial cells, adaptively refined, while N-body simulation CoDa I-DM2048, by Gadget2, used (2048)3 particles, to find reionization times for all galaxies at z = 0 with masses M(z = 0) ≥ 108 M ⊙. Galaxies with M(z=0)≳ {10}11 {M}⊙ reionized earlier than the universe as a whole, by up to ∼500 Myr, with significant scatter. For Milky Way-like galaxies, z R ranged from 8 to 15. Galaxies with M(z=0)≲ {10}11 {M}⊙ typically reionized as late or later than globally averaged 50% reionization at < {z}R> =7.8, in neighborhoods where reionization was completed by external radiation. The spread of reionization times within galaxies was sometimes as large as the galaxy-to-galaxy scatter. The Milky Way and M31 reionized earlier than global reionization but later than typical for their mass, neither dominated by external radiation. Their most-massive progenitors at z > 6 had z R =9.8 (MW) and 11 (M31), while their total masses had z R = 8.2 (both).
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Libeskind, N. I., van de Weygaert, R., Cautun, M., Falck, B., Tempel, E., Abel, T., Alpaslan, M., Aragón-Calvo, M. A., Forero-Romero, J. E., Gonzalez, R., Gottlöber, S., Hahn, O., Hellwing, W. A., Hoffman, Y., Jones, B. J. T., Kitaura, F., Knebe, A., Manti, S., Neyrinck, M., Nuza, S. E., Padilla, N., Platen, E., Ramachandra, N., Robotham, A., Saar, E., Shandarin, S., Steinmetz, M., Stoica, R. S., Sousbie, T., Yepes, G., 2018, Monthly Notices of the Royal Astronomical Society , 473, 1 , 1195
Published: January 2018
doi:10.1093/mnras/stx1976
Abstract:
The cosmic web is one of the most striking features of the distribution of galaxies and dark matter on the largest scales in the Universe. It is composed of dense regions packed full of galaxies, long filamentary bridges, flattened sheets and vast low-density voids. The study of the cosmic web has focused primarily on the identification of such features, and on understanding the environmental effects on galaxy formation and halo assembly. As such, a variety of different methods have been devised to classify the cosmic web - depending on the data at hand, be it numerical simulations, large sky surveys or other. In this paper, we bring 12 of these methods together and apply them to the same data set in order to understand how they compare. In general, these cosmic-web classifiers have been designed with different cosmological goals in mind, and to study different questions. Therefore, one would not a priori expect agreement between different techniques; however, many of these methods do converge on the identification of specific features. In this paper, we study the agreements and disparities of the different methods. For example, each method finds that knots inhabit higher density regions than filaments, etc. and that voids have the lowest densities. For a given web environment, we find a substantial overlap in the density range assigned by each web classification scheme. We also compare classifications on a halo-by-halo basis; for example, we find that 9 of 12 methods classify around a third of group-mass haloes (i.e. Mhalo ∼ 1013.5 h-1 M⊙) as being in filaments. Lastly, so that any future cosmic-web classification scheme can be compared to the 12 methods used here, we have made all the data used in this paper public.
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