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We explore the relationship between the thermal Sunyaev-Zel'dovich (tSZ) power spectrum amplitude and the halo mass and redshift of galaxy clusters in South Pole Telescope (SPT) data, in comparison with three $N$-body simulations combined with semi-analytical gas models of the intra-cluster medium. Specifically, we calculate both the raw and fractional power contribution to the full tSZ power spectrum amplitude at $\ell = 3000$ from clusters as a function of halo mass and redshift. We use nine mass bins in the range $1 \times 10^{14}\ M_\odot\ h^{-1} < M_{500} < 2 \times 10^{15}\ M_\odot\ h^{-1}$, and two redshift bins defined by $0.25 < z < 0.59$ and $0.59 < z < 1.5$. We additionally divide the raw power contribution in each mass bin by the number of clusters in that bin, as a metric for comparison of different gas models. At lower masses, the SPT data prefers a model that includes a mass-dependent bound gas fraction component and relatively high levels of AGN feedback, whereas at higher masses there is a preference for a model with a lower amount of feedback and a complete lack of non-thermal pressure support. The former provides the best fit to the data overall, in regards to all metrics for comparison. Still, discrepancies exist and the data notably exhibits a steep mass-dependence which all of the simulations fail to reproduce. This suggests the need for additional mass- and redshift-dependent adjustments to the gas models of each simulation, or the potential presence of contamination in the data at halo masses below the detection threshold of SPT-SZ. Furthermore, the data does not demonstrate significant redshift evolution in the per-cluster tSZ power spectrum contribution, in contrast to self-similar model predictions., Comment: 19 pages, 15 figures, 5 tables; accepted by the Open Journal of Astrophysics

We propose a cross-internal linear combination (cross-ILC) approach to measure the small-scale cosmic microwave background (CMB) anisotropies robustly against the contamination from astrophysical signals. In particular, we focus on the mitigation of systematics from cosmic infrared background (CIB) and thermal Sunyaev-Zeldovich (tSZ) signals in kinematic SZ (kSZ) power spectrum and CMB lensing. We show the cross-spectrum measurement between two CMB maps created by nulling the contributions from CIB (CIB-free map) and tSZ (tSZ-free map) to be robust for kSZ as the approach significantly suppresses the total contribution of CIB and tSZ signals. Similarly, for CMB lensing, we use the approach introduced by Madhavacheril & Hill (2018) but with a slight modification by using the tSZ-free and CIB-free maps in the two legs of the quadratic estimator. By cross-correlating the CMB lensing map created using this technique with galaxy surveys, we show that the biases from both CIB/tSZ are negligible. We also compute the impact of unmodeled CIB/tSZ residuals on kSZ and cosmological parameters finding that the kSZ measured using the standard ILC to be significantly biased. The kSZ estimate from the cross-ILC remains less affected by CIB/tSZ making it crucial for CMB surveys such as the South Pole Telescope (SPT), Simons Observatory (SO) and CMB-S4. With the cross-ILC method, we find the total kSZ power spectrum can be measured at very high significance: $35\sigma$ by SPT, $22\sigma$ by SO, and $80\sigma$ by CMB-S4. We forecast constraints on the epoch of reionization using the kSZ power spectrum and find that the duration of reionization, currently unconstrained by {\it Planck}, can be constrained to $\sigma(z_{\rm dur})$= 1.5 (or) 0.5 depending on the choice of $\tau_{\rm re}$ prior. The data products and codes can be downloaded from https://github.com/sriniraghunathan/cross_ilc_methods_paper., Comment: 23 pages, 12 figures, 4 tables; addressed minor comments from the reviewer; accepted for publication in ApJ; Data products and the associated codes can be downloaded from https://github.com/sriniraghunathan/cross_ilc_methods_paper

The tightest cosmological constraints currently available are obtained by combining complementary data sets. When combining correlated data sets, various astrophysical biases that affect the measurements must be identified and treated. There are numerous such biases, and they are often intricately related with one another via complex astrophysical effects, making them difficult to characterize analytically. Consequently, a simulation with multiple components implemented coherently is required to investigate these biases simultaneously and as a whole. In this work, a suite of simulated extragalactic skies is presented, including maps and/or catalogues of cosmic microwave background (CMB) lensing, thermal and kinetic Sunyaev-Zel'dovich (tSZ/kSZ) effects, cosmic infrared background (CIB), radio sources, galaxy overdensity and galaxy weak lensing. Each of these probes is implemented in the lightcone using halo catalogues and/or particles from the Multidark-Planck2 (MDPL2) N-body simulation, and the modelling is calibrated using hydrodynamic simulations and publicly available data. The auto- and cross-spectra of the individual probes, as well as the cross-spectra between the observables, are shown to be consistent with theoretical models and measurements from data. The simulation is shown to have a wide range of applications, including forecasting, pipeline testing, and evaluating astrophysical biases in cross-correlation studies. It is further demonstrated that the simulation products produced in this work have sufficient accuracy to recover the input cosmology when subjected to a full cosmological analysis and are ready for application in real-world analyses for ongoing and future surveys., Comment: 41 pages, 45 figures, 7 tables

While the probability density function (PDF) of the cosmic microwave background (CMB) convergence field approximately follows a Gaussian distribution, primordial non-Gaussianities and small contributions from structures at low redshifts make the overall distribution slightly non-Gaussian. Some of the late-time component can be modelled using the distribution of galaxies and subtracted off from the original CMB lensing map to produce a map of matter distribution at high redshifts. Using this high-redshift mass map, we are able to directly study the early phases of structure formation. In this work, we forecast the detectability of signatures of non-Gaussianity due to nonlinear structure formation at $z>1.2$. Assuming the optimal case of no systematics, we find that it is challenging to detect such signatures in current surveys, but future experiments such as the deep field of CMB-S4 will be able to make detections of $\sim7\sigma$., Comment: 10 pages, 9+3 figures. Comments welcome

The Rayleigh scattering of cosmic microwave background (CMB) photons off the neutral hydrogen produced during recombination effectively creates an additional scattering surface after recombination that encodes new cosmological information, including the expansion and ionization history of the universe. A first detection of Rayleigh scattering is a tantalizing target for next-generation CMB experiments. We have developed a Rayleigh scattering forecasting pipeline that includes instrumental effects, atmospheric noise, and astrophysical foregrounds (e.g., Galactic dust, cosmic infrared background, or CIB, and the thermal Sunyaev-Zel'dovich effect). We forecast the Rayleigh scattering detection significance for several upcoming ground-based experiments, including SPT-3G+, Simons Observatory, CCAT-prime, and CMB-S4, and examine the limitations from atmospheric and astrophysical foregrounds as well as potential mitigation strategies. When combined with Planck data, we estimate that the ground-based experiments will detect Rayleigh scattering with a significance between 1.6 and 3.7, primarily limited by atmospheric noise and the CIB., Comment: 19 pages, 7 figures (v2 additional author added)

This is a solicited whitepaper for the Snowmass 2021 community planning exercise. The paper focuses on measurements and science with the Cosmic Microwave Background (CMB). The CMB is foundational to our understanding of modern physics and continues to be a powerful tool driving our understanding of cosmology and particle physics. In this paper, we outline the broad and unique impact of CMB science for the High Energy Cosmic Frontier in the upcoming decade. We also describe the progression of ground-based CMB experiments, which shows that the community is prepared to develop the key capabilities and facilities needed to achieve these transformative CMB measurements., Comment: contribution to Snowmass 2021

This Snowmass 2021 White Paper describes the Cosmic Microwave Background Stage 4 project CMB-S4, which is designed to cross critical thresholds in our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. We provide an overview of the science case, the technical design, and project plan., Comment: Contribution to Snowmass 2021. arXiv admin note: substantial text overlap with arXiv:1908.01062, arXiv:1907.04473

Powerful new observational facilities will come online over the next decade, enabling a number of discovery opportunities in the "Cosmic Frontier", which targets understanding of the physics of the early universe, dark matter and dark energy, and cosmological probes of fundamental physics, such as neutrino masses and modifications of Einstein gravity. Synergies between different experiments will be leveraged to present new classes of cosmic probes as well as to minimize systematic biases present in individual surveys. Success of this observational program requires actively pairing it with a well-matched state-of-the-art simulation and modeling effort. Next-generation cosmological modeling will increasingly focus on physically rich simulations able to model outputs of sky surveys spanning multiple wavebands. These simulations will have unprecedented resolution, volume coverage, and must deliver guaranteed high-fidelity results for individual surveys as well as for the cross-correlations across different surveys. The needed advances are as follows: (1) Development of scientifically rich and broadly-scoped simulations, which capture the relevant physics and correlations between probes (2) Accurate translation of simulation results into realistic image or spectral data to be directly compared with observations (3) Improved emulators and/or data-driven methods serving as surrogates for expensive simulations, constructed from a finite set of full-physics simulations (4) Detailed and transparent verification and validation programs for both simulations and analysis tools. (Abridged), Comment: Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021)

Cosmological data in the next decade will be characterized by high-precision, multi-wavelength measurements of thousands of square degrees of the same patches of sky. By performing multi-survey analyses that harness the correlated nature of these datasets, we will gain access to new science, and increase the precision and robustness of science being pursued by each individual survey. However, effective application of such analyses requires a qualitatively new level of investment in cross-survey infrastructure, including simulations, associated modeling, coordination of data sharing, and survey strategy. The scientific gains from this new level of investment are multiplicative, as the benefits can be reaped by even present-day instruments, and can be applied to new instruments as they come online., Comment: Contribution to Snowmass 2021

The origin of the bulk of the astrophysical neutrinos detected by the IceCube Observatory remains a mystery. Previous source-finding analyses compare the directions of IceCube events and individual sources in astrophysical catalogs. The source association method is technically challenging when the number of source candidates is much larger than the number of the observed astrophysical neutrinos. We show that in this large source number regime, a cross-correlation analysis of neutrino data and source catalog can instead be used to constrain potential source populations for the high-energy astrophysical neutrinos, and provide spatial evidence for the existence of astrophysical neutrinos. We present an analysis of the cross-correlation of the IceCube 2010-2012 point-source data and a WISE-2MASS galaxy sample. While we find no significant detection of cross-correlation with the publicly available neutrino dataset, we show that, when applied to the full IceCube data, which has a longer observation time and higher astrophysical neutrino purity, our method has sufficient statistical power to detect a cross-correlation signal if the neutrino sources trace the Large Scale Structure of the Universe., Comment: 10 pages, 6 figures. Comments welcome

We examine the effects of magnitude, colour, and Ly-alpha equivalent width (EW) on the spatial distribution of z~3 Lyman break galaxies (LBGs) and report significant differences in their auto-correlation functions (ACFs). The results are obtained using samples of ~10,000-57,000 LBGs from the Canada-France-Hawaii Telescope Legacy Survey. We find that magnitude has a larger effect on the ACF amplitude on small scales (<~1 Mpc) and that colour is more influential on large scales (>~1 Mpc). We find the most significant differences between ACFs for LBGs with dominant net Ly-alpha EW in absorption (aLBGs) and dominant net Ly-alpha EW in emission (eLBGs) determined from >~95% pure samples of each population using a photometric technique calibrated from ~1000 spectra. The aLBG ACF one-halo term departs from a power law fit near ~1 Mpc, corresponding to the virial radii of M_DM ~10^13 M_solar haloes, and shows a strong two-halo term amplitude. In contrast, the eLBG ACF one-halo term departs at ~0.12 Mpc, suggesting parent haloes of M_DM ~10^11 M_solar, and a two-halo term that exhibits a `hump' on intermediate scales that we localize to the faintest, bluest members. We find that the `hump' can be well fit with a model in which a significant fraction of eLBGs reside on shells. The auto- and cross-correlation functions indicate that aLBGs are found in massive, group-like haloes and that eLBGs are found largely on group outskirts and in the field. Ly-alpha is a tracer of several intrinsic LBG properties, including morphology, implying that the mechanisms behind the morphology-density relation are in place at z~3 and that Ly-alpha EW may be a key environment diagnostic. Finally, our results show that the mass of LBGs has been underestimated because the LBG ACF amplitude is lower than the true average as a result of the spatial anti-correlation of the spectral sub-types (abridged)., Comment: 22 pages, 14 figures, 2 tables, submitted to MNRAS

A rare class of `super-luminous' supernovae that are about ten or more times more luminous at their peaks than other types of luminous supernovae has recently been found at low to intermediate redshifts. A small subset of these events have luminosities that evolve slowly and result in radiated energies of around 10^51 ergs or more. Therefore, they are likely examples of `pair-instability' or `pulsational pair-instability' supernovae with estimated progenitor masses of 100 - 250 times that of the Sun. These events are exceedingly rare at low redshift, but are expected to be more common at high redshift because the mass distribution of the earliest stars was probably skewed to high values. Here we report the detection of two super-luminous supernovae, at redshifts of 2.05 and 3.90, that have slowly evolving light curves. We estimate the rate of events at redshifts of 2 and 4 to be approximately ten times higher than the rate at low redshift. The extreme luminosities of super-luminous supernovae extend the redshift limit for supernova detection using present technology, previously 2.36, and provide a way of investigating the deaths of the first generation of stars to form after the Big Bang., Comment: Accepted version of the paper (3 pages, 1 table, 3 figures) appearing in Nature, including Supplementary Information (11 pages, 2 tables, 5 figures)