Cold Dark Matter Power Spectrum Research Articles

Structure formation with primordial black holes to alleviate early star formation tension revealed by JWST

This Letter explores the potential role of primordial black holes (PBHs) to address cosmological tensions as the presence of more massive than expected galaxies at high redshifts, as indicated by recent James Webb Space Telescope observations. Motivated by inflation models that enhance the power at scales beyond the observable range that produce PBHs with Schechter-like mass functions, we aim to explain the excess of high redshift galaxies via a modification of the Lambda cold dark matter power spectrum that consists in adding (i) a blue spectral index $n_b$ at $k_ piv =10/$Mpc and (ii) Poisson and isocurvature contributions from massive PBHs that only make up $0.5<!PCT!>$ of the dark matter. We simulated these models using the SWIFT code and find an increased abundance of high redshift galaxies in simulations that include PBHs. We compared these models to estimates from James Webb Space Telescope observations. Unlike the Lambda cold dark matter model, the inclusion of PBHs allowed us to reproduce the the observations with reasonable values for the star formation efficiency. Furthermore, the power spectra we adopted potentially produce PBHs that can serve as seeds for supermassive black holes with masses $7.57 odot

A minimal model for massive neutrinos in Newtonian N-body simulations

We present a novel method for including the impact of massive neutrinos in cold dark matter N-body simulations. Our approach is compatible with widely employed Newtonian N-body codes and relies on only three simple modifications. First, we use commonly employed backscaling initial conditions, based on the cold dark matter plus baryon power spectrum instead of the total matter power spectrum. Second, the accurate Hubble rate is employed in both the backscaling and the evolution of particles in the N-body code. Finally, we shift the final particle positions in a post-processing step to account for the integrated effect of neutrinos on the particles in the simulation. However, we show that the first two modifications already capture most of the relevant neutrino physics for a large range of observationally interesting redshifts and scales. The output of the simulations are the cold dark matter and baryon distributions and can be analysed using standard methods. All modifications are simple to implement and do not generate any computational overhead. By implementing our methods in the N-body codes gadget-4 and gevolution, we show that any state-of-the-art Newtonian N-body code can be utilised out of the box. Our method is also compatible with higher order Lagrangian perturbation theory initial conditions and accurate for masses up to at least ∑ mν = 0.3 eV. Being formulated in relativistic gauge theory, in addition to including the impact of massive neutrinos, our method further includes relativistic corrections relevant on the large scales for free.

Neutrinos in N -body simulations

In the next decade, cosmological surveys will have the statistical power to detect the absolute neutrino mass scale. $N$-body simulations of large-scale structure formation play a central role in interpreting data from such surveys. Yet these simulations are Newtonian in nature. We provide a quantitative study of the limitations to treating neutrinos, implemented as $N$-body particles, in $N$-body codes, focusing on the error introduced by neglecting special relativistic effects. Special relativistic effects are potentially important due to the large thermal velocities of neutrino particles in the simulation box. We derive a self-consistent theory of linear perturbations in Newtonian and nonrelativistic neutrinos and use this to demonstrate that $N$-body simulations overestimate the neutrino free-streaming scale, and cause errors in the matter power spectrum that depend on the initial redshift of the simulations. For ${z}_{i}\ensuremath{\lesssim}100$, and neutrino masses within the currently allowed range, this error is $\ensuremath{\lesssim}0.5%$, though represents an up to $\ensuremath{\sim}10%$ correction to the shape of the neutrino-induced suppression to the cold dark matter power spectrum. We argue that the simulations accurately model nonlinear clustering of neutrinos so that the error is confined to linear scales.

CMB anisotropies generated by cosmic string loops

We investigate the contribution of cosmic string loops to the cosmic microwave background (CMB) anisotropies. This is done by extending the unconnected segment model (USM) to include the contribution of the cosmic string loops created throughout the cosmological evolution of a cosmic string network to the stress-energy tensor. We then implement this extended USM in the publicly available CMBACT code and obtain the linear cold dark matter power spectrum and the CMB angular power spectra generated by cosmic string loops. We find that the shape of the angular power spectra generated by loops is, in general, similar to that of long strings. However, there is generally an enhancement of the anisotropies on small angular scales. Vector modes produced by loops dominate over those produced by long strings for large multipole moments $\ensuremath{\ell}$. The contribution of loops to the CMB anisotropies generated by cosmic string networks may reach a level of 10% for large loops but decreases as the size of loops decreases. This contribution may then be significant and, thus, this extension provides a more accurate prediction of the CMB anisotropies generated by cosmic string networks.

Power spectrum of density fluctuations, halo abundances, and clustering with primordial black holes

ABSTRACT We study the effect of dark matter (DM) being encapsulated in primordial black holes (PBHs) on the power spectrum of density fluctuations P(k); we also look at its effect on the abundance of haloes and their clustering. We allow the growth of Poisson fluctuations since matter and radiation equality and study both monochromatic and extended PBH mass distributions. We present updated monochromatic black hole mass constraints by demanding $\lt 10{{\ \rm per\ cent}}$ deviations from the Λ cold dark matter (CDM) power spectrum at a scale of k = 1 h Mpc−1. Our results show that PBHs with masses $\gt 10^4\, h^{-1}\, \mathrm{M}_\odot$ are excluded from conforming all of the DM in the Universe. We also apply this condition to our extended Press–Schechter (PS) mass functions, and find that the Poisson power is scale dependent even before applying evolution. We find that characteristic masses $M^*\le 10^2 \, \mathrm{ h}^{-1}\, \mathrm{M}_\odot$ are allowed, leaving only two characteristic PBH mass windows of PS mass functions when combining with previous constraints, at $M^*\sim 10^2\, h^{-1}\, \mathrm{M}_\odot$ and $\sim \!10^{-8}\, h^{-1}\, \mathrm{M}_\odot$ where all of the DM can be in PBHs. The resulting DM halo mass functions within these windows are similar to those resulting from CDM made of fundamental particles. However, as soon as the parameters produce unrealistic P(k), the resulting halo mass functions and their bias as a function of halo mass deviate strongly from the behaviour measured in the real Universe.

First Detection of Scale-Dependent Linear Halo Bias in N-Body Simulations with Massive Neutrinos.

Using N-body simulations with massive neutrino density perturbations, we detect the scale-dependent linear halo bias with high significance. This is the first time that this effect is detected in simulations containing neutrino density perturbations on all scales, confirming the same finding from separate universe simulations. The scale dependence is the result of the additional scale in the system, i.e., the massive neutrino free-streaming length, and it persists even if the bias is defined with respect to the cold dark matter plus baryon (instead of total matter) power spectrum. The separate universe approach provides a good model for the scale-dependent linear bias, and the effect is approximately 0.25f_{ν} and 0.43f_{ν} for halos with bias of 1.7 and 3.5, respectively. While the size of the effect is small, it is not insignificant in terms of f_{ν} and should therefore be included to accurately constrain neutrino mass from clustering statistics of biased tracers. More importantly, this feature is a distinct signature of free-streaming particles and cannot be mimicked by other components of the standard cosmological model.

Scale-dependent bias and bispectrum in neutrino separate universe simulations

Cosmic background neutrinos have a large velocity dispersion, which causes the evolution of long-wavelength density perturbations to depend on scale. This scale-dependent growth leads to the well-known suppression in the linear theory matter power spectrum that is used to probe neutrino mass. In this paper, we study the impact of long-wavelength density perturbations on small-scale structure formation. By performing separate universe simulations where the long-wavelength mode is absorbed into the local expansion, we measure the responses of the cold dark matter (CDM) power spectrum and halo mass function, which correspond to the squeezed-limit bispectrum and halo bias. We find that the scale-dependent evolution of the long-wavelength modes causes these quantities to depend on scale and provide simple expressions to model them in terms of scale and the amount of massive neutrinos. Importantly, this scale-dependent bias reduces the suppression in the linear halo power spectrum due to massive neutrinos by 13 and 26% for objects of bias $\bar{b}=2$ and $\bar{b} \gg1$, respectively. We demonstrate with high statistical significance that the scale-dependent halo bias ${\it cannot}$ be modeled by the CDM and neutrino density transfer functions at the time when the halos are identified. This reinforces the importance of the temporal nonlocality of structure formation, especially when the growth is scale dependent.

Power spectrum of dark matter substructure in strong gravitational lenses

Studying the smallest self-bound dark matter structure in our Universe can yield important clues about the fundamental particle nature of dark matter. Galaxy-scale strong gravitational lensing provides a unique way to detect and characterize dark matter substructures at cosmological distances from the Milky Way. Within the cold dark matter (CDM) paradigm, the number of low-mass subhalos within lens galaxies is expected to be large, implying that their contribution to the lensing convergence field is approximately Gaussian and could thus be described by their power spectrum. We develop here a general formalism to compute from first principles the substructure convergence power spectrum for different populations of dark matter subhalos. As an example, we apply our framework to two distinct subhalo populations: a truncated Navarro-Frenk-White subhalo population motivated by standard CDM, and a truncated cored subhalo population motivated by self-interacting dark matter (SIDM). We study in detail how the subhalo abundance, mass function, internal density profile, and concentration affect the amplitude and shape of the substructure power spectrum. We determine that the power spectrum is mostly sensitive to a specific combination of the subhalo abundance and moments of the mass function, as well as to the average tidal truncation scale of the largest subhalos included in the analysis. Interestingly, we show that the asymptotic slope of the substructure power spectrum at large wave number reflects the internal density profile of the subhalos. In particular, the SIDM power spectrum exhibits a characteristic steepening at large wave number absent in the CDM power spectrum, opening the possibility of using this observable, if at all measurable, to discern between these two scenarios.

Linear perturbation theory for tidal streams and the small-scale CDM power spectrum

Tidal streams in the Milky Way are sensitive probes of the population of dark-matter subhalos predicted in cold-dark-matter (CDM) simulations. We present a new calculus for computing the effect of subhalo fly-bys on cold tidal streams based on the action-angle representation of streams. The heart of this calculus is a line-of-parallel-angle approach that calculates the perturbed distribution function of a given stream segment by undoing the effect of all impacts. This approach allows one to compute the perturbed stream density and track in any coordinate system in minutes for realizations of the subhalo distribution down to 10^5 Msun, accounting for the stream's internal dispersion and overlapping impacts. We study the properties of density and track fluctuations with suites of simulations. The one-dimensional density and track power spectra along the stream trace the subhalo mass function, with higher-mass subhalos producing power only on large scales, while lower mass subhalos cause structure on smaller scales. The time-dependence of impacts and of the evolution of the stream after an impact gives rise to bispectra. We further find that tidal streams are essentially corrugated sheets in the presence of subhalo perturbations: different projections of the track all reflect the same pattern of perturbations, facilitating their observational measurement. We apply this formalism to density data for the Pal 5 stream and make a first rigorous determination of 10^{+11}_{-6} dark-matter subhalos with masses between 3x10^6 and 10^9 Msun within 20 kpc from the Galactic center (corresponding to 1.4^{+1.6}_{-0.9} times the number predicted by CDM-only simulations or to f_{sub}(r<20 kpc) ~ 0.2%). Improved data will allow measurements of the subhalo mass function down to 10^5 Msun, thus definitively testing whether dark matter clumps on the smallest scales relevant for galaxy formation.

DEMNUni: the clustering of large-scale structures in the presence of massive neutrinos

We analyse the clustering features of Large Scale Structures (LSS) in the presence of massive neutrinos, employing a set of large-volume, high-resolution cosmological N-body simulations, where neutrinos are treated as separate collisionless particles. The volume of 8 h-3 Gpc3, combined with a resolution of about 8×1010h-1M⊚ for the cold dark matter (CDM) component, represents a significant improvement over previous N-body simulations in massive neutrino cosmologies. In this work we focus, in the first place, on the analysis of nonlinear effects in CDM and neutrinos perturbations contributing to the total matter power spectrum. We show that most of the nonlinear evolution is generated exclusively by the CDM component. We therefore compare mildly nonlinear predictions from Eulerian Perturbation Theory (PT), and fully nonlinear prescriptions (HALOFIT) with the measurements obtained from the simulations. We find that accounting only for the nonlinear evolution of the CDM power spectrum allows to recover the total matter power spectrum with the same accuracy as the massless case. Indeed, we show that, the most recent version of the (HALOFIT) formula calibrated on ΛCDM simulations can be applied directly to the linear CDM power spectrum without requiring additional fitting parameters in the massive case. As a second step, we study the abundance and clustering properties of CDM halos, confirming that, in massive neutrino cosmologies, the proper definition of the halo bias should be made with respect to the cold rather than the total matter distribution, as recently shown in the literature. Here we extend these results to the redshift space, finding that, when accounting for massive neutrinos, an improper definition of the linear bias can lead to a systematic error of about 1-2 % in the determination of the linear growth rate from anisotropic clustering. This result is quite important if we consider that future spectroscopic galaxy surveys, as e.g. Euclid, are expected to measure the linear growth-rate with statistical errors less than about 3 % at z≲1.

The halo model in a massive neutrino cosmology

We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a ∼20% accuracy up to very non-linear scales ofk = 10 h/Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range k = 0.5 – 1 h/Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales k < 0.2 h/Mpc our neutrino halo model agrees with the results of N-body simulations at the level of 8% for total neutrino masses of < 0.3 eV. We also model the neutrino non-linear density field as a sum of a linear and clustered component and predict the neutrino power spectrum and the cold dark matter-neutrino cross-power spectrum up to k = 1 h/Mpc with ∼30% accuracy. For masses below 0.15 eV the neutrino halo model captures the neutrino induced suppression, casted in terms of matter power ratios between massive and massless scenarios, with a 2% agreement with the results of N-body/neutrino simulations. Finally, we provide a simple application of the halo model: the computation of the clustering of galaxies, in massless and massive neutrinos cosmologies, using a simple Halo Occupation Distribution scheme and our halo model extension.

Effects of the cosmological constant on cold dark matter clusters

Context. Cold dark matter inhomogeneities are considered in a homogeneous background of matter, radiation, and the cosmological constant in a flat universe. Aims. We investigate the influence of the cosmological constant on the non-linear collapse of cold dark matter clusters. Methods. For simplicity, a spherical infall model has been used to describe the collapse of non-relativistic mass shells; besides, an average distribution of density around a cluster of galaxies has been taken. Boundary conditions are imposed by the solution of the linearized equation for the growth of matter perturbations and by the cold dark matter power spectrum. Results. For an average cluster, the radii of shells and masses enclosed by them have been obtained at their zero proper acceleration (ZA) redshifts, at their turn-around (TA) redshifts and at their virialization (VIR) redshifts. According to our results at present, the shell that reaches its turn-around point shows [r TA ]0 = 6.85 Mpc and [M TA ]0 = 6.76 × 10 14 M� . The virializing shell fulfills [r TA ]0 = 4.57 [r VIR ]0 and [M TA ]0 = 1.95 [M VIR ]0. These results differ appreciably from those derived from a model with cosmological constant equal to zero in a flat universe: [r TA ( Λ= 0)]0 = 6.62 [r VIR ( Λ= 0)]0 and [M TA ( Λ= 0)]0 = 5.26 [M VIR ( Λ= 0)]0 ;t his discrepancy could be considered as a new independent proof of the existence of dark energy. The shell with zero proper acceleration presents [r ZA ]0 = 1.59 [r TA ]0 and [M ZA ]0 = 1.63 [M TA ]0. We have found that there is a limit to the mass of the average cluster, which is able to virialize; its value is {M VIR }MAX = 8.1 × 10 14 M� . As expected, we found that shells present null proper acceleration at redshift values that are smaller than 0.755. Conclusions. We have noticed that the cosmological constant imposes an upper limit for the mass enclosed by shells, which are able to reach zero proper velocity. Hence, this mass is the maximum mass of the virialized core, {M VIR }MAX. For the average cluster addressed in this work, the value is 2.34 times the mass of the virialized core at present. Shells enclosing masses M > {M VIR }MAX achieve zero proper acceleration and speed up, moving away from the virialized core, and never reach a turn-around point. Shells with M�{ M VIR }MAX show zero proper aceleration at redshifts close to that at which the universe background acceleration is null. Finally, we have found that the relation between shell proper velocities and their radii can be adjusted by a straight line at z = 0a nd from approximately 20 up to 40 Mpc; however, this line does not intercept the origin as velocities due to the Hubble flux do.

Statistics of dark matter halos in the excursion set peak framework

We derive approximated, yet very accurate analytical expressions for the abundance and clustering properties of dark matter halos in the excursion set peak framework; the latter relies on the standard excursion set approach, but also includes the effects of a realistic filtering of the density field, a mass-dependent threshold for collapse, and the prescription from peak theory that halos tend to form around density maxima. We find that our approximations work excellently for diverse power spectra, collapse thresholds and density filters. Moreover, when adopting a cold dark matter power spectra, a tophat filtering and a mass-dependent collapse threshold (supplemented with conceivable scatter), our approximated halo mass function and halo bias represent very well the outcomes of cosmological N-body simulations.

Full investigation on the dynamics of power-law kinetic quintessence

We give a full investigation on the dynamics of power-law kinetic quintessence $L(X,\ensuremath{\phi})=V(\ensuremath{\phi})(\ensuremath{-}X+{X}^{2})$ by considering the potential related parameter $\mathrm{\ensuremath{\Gamma}}(=\frac{V{V}^{\ensuremath{'}\ensuremath{'}}}{{{V}^{\ensuremath{'}}}^{2}})$ as a function of another potential parameter $\ensuremath{\lambda}(=\frac{{V}^{\ensuremath{'}}}{\ensuremath{\kappa}{V}^{3/2}})$, which correspondingly extends the analysis of the dynamical system of our Universe from two dimensional to three dimensional. In addition to the critical points found in previous papers, we find a new de Sitter-- like dominant attractor ($cp6$) and give its stable condition using the center manifold theorem. For the dark energy dominant solution ($cp6$ and $cp7$), it could be distinguished from canonical quintessence and tachyon models since the sound speed ${c}_{s}^{2}=0$ or ${c}_{s}^{2}\ensuremath{\ll}1$. For the scaling solution ($cp8$), it is very interesting that the sound speed ${c}_{s}^{2}=1/5$, while it behaves as ordinary matter. We therefore point out that the power-law kinetic quintessence should have different signatures on the cold dark matter power spectrum and the cosmic microwave background both at early time, when this scalar field is an early dark energy with ${\mathrm{\ensuremath{\Omega}}}_{\ensuremath{\phi}}$ being non-negligible at high redshift, and at late time, when it drives the accelerating expansion. We still do not know whether there are any degeneracies of the impacts between these two epoches. They are expected to be investigated in future.

On the effect of the ionizing background on the Lyα forest autocorrelation function

An analytical framework is presented to understand the effects of a fluctuating intensity of the cosmic ionizing background on the correlations of the Lyα forest transmission fraction measured in quasar spectra. In the absence of intensity fluctuations, the Lyα power spectrum should have the expected cold dark matter power spectrum with redshift distortions in the linear regime, with a bias factor bδ and a redshift distortion parameter β that depend on redshift but are independent of scale. The intensity fluctuations introduce a scale dependence in both bδ and β, but keeping their product bδβ fixed. Observations of the Lyα correlations and cross-correlations with radiation sources like those being done at present in the Baryon Oscillation Spectroscopic Survey of Sloan Digital Sky Survey third generation have the potential to measure this scale dependence, which reflects the biasing properties of the sources and absorbers of the ionizing background. We also compute a second term affecting the Lyα spectrum, due to shot noise in the sources of radiation. This term is very large if luminous quasars are assumed to produce the ionizing background and to emit isotropically with a constant luminosity, but should be reduced by a contribution from galaxies, and by the finite lifetime and anisotropic emission of quasars.

Effect of dark energy sound speed and equation of state on CDM power spectrum

We have studied the influence of equation of state w, and effective sound speed ce of the dark energy perturbations on the cold dark matter (CDM) power spectrum. We have considered different cases of the equation of state and the effective sound speed, and the CDM power spectrum is found to be generically suppressed in these cases as compared to the ΛCDM model. The suppression at different length scales depends on the value of ω and ce, and the effect of different ω is profoundly seen at all length scales. The influence of sound speed is significantly seen only at the intermediate length scales, and is negligible at scales very much larger and smaller than the Hubble scale.

Cosmology with massive neutrinos I: towards a realistic modeling of the relation between matter, haloes and galaxies

By using a suite of large box-size N-body simulations that incorporate massive neutrinos as an extra set of particles, with total masses of 0.15, 0.30, and 0.60 eV, we investigate the impact of neutrino masses on the spatial distribution of dark matter haloes and on the distribution of galaxies within the haloes. We compute the bias between the spatial distribution of dark matter haloes and the overall matter and cold dark matter distributions using statistical tools such as the power spectrum and the two-point correlation function. Overall we find a scale-dependent bias on large scales for the cosmologies with massive neutrinos. In particular, we find that the bias decreases with the scale, being this effect more important for higher neutrino masses and at high redshift. However, our results indicate that the scale-dependence in the bias is reduced if the latter is computed with respect to the cold dark matter distribution only. We find that the value of the bias on large scales is reasonably well reproduced by the Tinker fitting formula once the linear cold dark matter power spectrum is used, instead of the total matter power spectrum. We also investigate whether scale-dependent bias really comes from purely neutrino's effect or from nonlinear gravitational collapse of haloes. For this purpose, we address the Ων-σ8 degeneracy and find that such degeneracy is not perfect, implying that neutrinos imprint a slight scale dependence on the large-scale bias. Finally, by using a simple halo occupation distribution (HOD) model, we investigate the impact of massive neutrinos on the distribution of galaxies within dark matter haloes. We use the main galaxy sample in the Sloan Digital Sky Survey (SDSS) II Data Release 7 to investigate if the small-scale galaxy clustering alone can be used to discriminate among different cosmological models with different neutrino masses. Our results suggest that different choices of the HOD parameters can reproduce the observational measurements relatively well, and we quantify the difference between the values of the HOD parameters between massless and massive neutrino cosmologies.

Cosmology with massive neutrinos II: on the universality of the halo mass function and bias

We use a large suite of N-body simulations to study departures from universality in halo abundances and clustering in cosmologies with non-vanishing neutrino masses. To this end, we study how the halo mass function and halo bias factors depend on the scaling variable σ2(M,z), the variance of the initial matter fluctuation field, rather than on halo mass M and redshift z themselves. We show that using the variance of the cold dark matter rather than the total mass field, i.e., σ2cdm(M,z) rather than σ2m(M,z), yields more universal results.Analysis of halo bias yields similar conclusions: when large-scale halo bias is defined with respect to the cold dark matter power spectrum, the result is both more universal, and less scale- or k-dependent. These results are used extensively in Papers I and III of this series.

Cosmology with massive neutrinos III: the halo mass function andan application to galaxy clusters

We use a suite of N-body simulations that incorporate massive neutrinos as an extra-set of particles to investigate their effect on the halo mass function. We show that for cosmologies with massive neutrinos the mass function of dark matter haloes selected using the spherical overdensity (SO) criterion is well reproduced by the fitting formula of Tinker et al. (2008) once the cold dark matter power spectrum is considered instead of the total matter power, as it is usually done. The differences between the two implementations, i.e. using Pcdm(k) instead of Pm(k), are more pronounced for large values of the neutrino masses and in the high end of the halo mass function: in particular, the number of massive haloes is higher when Pcdm(k) is considered rather than Pm(k). As a quantitative application of our findings we consider a Planck-like SZ-clusters survey and show that the differences in predicted number counts can be as large as 30% for ∑mν = 0.4 eV. Finally, we use the Planck-SZ clusters sample, with an approximate likelihood calculation, to derive Planck-like constraints on cosmological parameters. We find that, in a massive neutrino cosmology, our correction to the halo mass function produces a shift in the σ8(Ωm/0.27)γ relation which can be quantified as Δγ ∼ 0.05 and Δγ ∼ 0.14 assuming one (Nν = 1) or three (Nν = 3) degenerate massive neutrino, respectively. The shift results in a lower mean value of σ8 with Δσ8 = 0.01 for Nν = 1 and Δσ8 = 0.02 for Nν = 3, respectively. Such difference, in a cosmology with massive neutrinos, would increase the tension between cluster abundance and Planck CMB measurements.

THE COSMIC EVOLUTION OF FAINT SATELLITE GALAXIES AS A TEST OF GALAXY FORMATION AND THE NATURE OF DARK MATTER

The standard cosmological model based on cold dark matter (CDM) predicts a large number of subhalos for each galaxy-size halo. Matching the subhalos to the observed properties of luminous satellites of galaxies in the local universe poses a significant challenge to our understanding of the astrophysics of galaxy formation. We show that the cosmic evolution and host mass dependence of the luminosity function of satellites provide a powerful new diagnostic to disentangle astrophysical effects from variations in the underlying dark matter mass function. We illustrate this by comparing recent observations of satellites between redshifts 0.1 < z < 0.8 based on Hubble Space Telescope images, with predictions from three different state-of-the-art semi-analytic models applied to CDM power spectra, with one model also applied to a warm dark matter (WDM) spectrum. We find that even though CDM models provide a reasonable fit to the local luminosity function of satellites around galaxies comparable to the Milky Way, they do not reproduce the data as well for different redshifts and host galaxy stellar masses, indicating that further improvements in the description of star formation are likely needed. The WDM model matches the observed mass dependence and redshift evolution of satellite galaxies more closely, indicating that a modification of the underlying power spectrum may offer an alternative solution to this tension. We conclude by presenting predictions for the color distribution of satellite galaxies to demonstrate how future observations will be able to further distinguish between these models and to help constrain baryonic and non-baryonic physics.