We present a realistic 2000 deg$^{2}$ H$α$ galaxy mock catalog with $1<z<2$ for the Nancy Grace Roman Space Telescope galaxy redshift survey, the High Latitude Spectroscopic Survey (HLSS), created using Galacticus, a semi-analytical galaxy formation model, and high resolution cosmological N-body simulations. Galaxy clustering can probe dark energy and test gravity via baryon acoustic oscillation (BAO) and redshift space distortion (RSD) measurements. Using our realistic mock as the simulated Roman HLSS data, and a covariance matrix computed using a large set of approximate mocks created using EZmock, we investigate the expected precision and accuracy of the BAO and RSD measurements using the same analysis techniques used in analyzing real data. We find that the Roman H$α$ galaxy survey alone can measure the angular diameter distance with 2\% uncertainty, the Hubble parameter with 3-6\% uncertainty, and the linear growth parameter with 7\% uncertainty, in each of four redshift bins. Our realistic forecast illustrates the power of the Roman galaxy survey in probing the nature of dark energy and testing gravity.
Recently, the Nancy Grace Roman Space Telescope (Roman) Project raised the possibility of adding another filter to Roman. Based on the Filter Working Group's recommendations, this filter may be a K-band filter, extending significantly redder than the current-reddest F184. Among other scientific possibilities, this K filter raises the possibility of measuring SNe Ia in the rest-frame NIR out to higher redshifts than is possible with the current filter complement. I perform a simple survey optimization for NIR SN Ia distances with Roman, simultaneously optimizing both filter cutoffs and survey s…
Cosmology Constraints from Type Ia Supernova Simulations of the Nancy Grace Roman Space Telescope Strategy Recommended by the High Latitude Time Domain Survey Definition Committee
The weak lensing magnification of Type Ia Supernovae (SNe Ia) is sensitive to the clustering of matter, and provides an independent cosmological probe complementary to SN Ia distance measurements. The Nancy Grace Roman Space Telescope is uniquely sensitive to this measurement as it can discover high redshift SNe Ia and measure them with high precision. We present a methodology for reconstructing the probability distribution of the weak lensing magnification $μ$ of SNe Ia, $p(μ)$, from observational data, and using it to constrain cosmological parameters. We find that the reconstructed $p(μ)$ c…
The dark matter subhalo mass function is a promising way of distinguishing between dark matter models. While cold dark matter predicts halos down to Earth-sized masses, other dark matter models typically predict a cut-off in the subhalo mass function. Thus a definitive detection or limits on the existence of subhalos at small masses can give us insight into the nature of dark matter. If these subhalos exist in the Milky Way, they would produce weak lensing signatures, such as modified apparent positions, on background stars. These signatures would generate correlations in the apparent velociti…
We review the needs of the supernova community for improvements in survey coordination and data sharing that would significantly boost the constraints on dark energy using samples of Type Ia supernovae from the Vera C. Rubin Observatories, the \textit{Nancy Grace Roman Space Telescope}, and the \textit{Euclid} Mission. We discuss improvements to both statistical and systematic precision that the combination of observations from these experiments will enable. For example, coordination will result in improved photometric calibration, redshift measurements, as well as supernova distances. We also…
The Nancy Grace Roman Space Telescope (Roman) is an observatory for both wide-field observations and coronagraphy that is scheduled for launch in the mid 2020's. Part of the planned survey is a deep, cadenced field or fields that enable cosmological measurements with type Ia supernovae (SNe Ia). With a pixel scale of 0".11, the Wide Field Instrument will be undersampled, presenting a difficulty for precisely subtracting the galaxy light underneath the SNe. We use simulated data to validate the ability of a forward-model code (such codes are frequently also called "scene-modeling" codes) to per…
We present measurements of the linear galaxy bias of H$α$ and [OIII] emission line galaxies (ELGs) for the High Latitude Spectroscopic Survey (HLSS) of Nancy Grace Roman Space Telescope, using galaxy mocks constructed using semi-analytical model for galaxy formation, {\it Galacticus}, with a large cosmic volume and redshift coverage. We compute the two-point statistics of galaxies in configuration space and measure linear bias within scales of $10\sim50 h^{-1}$Mpc. We adopt different selection algorithms to investigate the impact of the Roman line flux cut, as well as the effect of dust model …
We simulate the emission line galaxy properties for the Nancy Grace Roman Space Telescope by creating a 4 deg$^{2}$ galaxy mock catalog using Galacticus, a semi-analytic model (SAM) for galaxy formation and evolution. The simulated galaxy properties include emission line luminosity, equivalent width (EW), broad band photometry, and spectral energy distribution (SED). We compare this mock catalog with the latest observational data from WISP and MOSDEF. We find that our Galacticus model makes predictions consistent with observational data, over a wide redshift range for multiple emission lines. …
This work presents a set of studies addressing the use of the low-dispersion slitless prism on Roman for SN spectroscopy as part of the Roman High Latitude Time Domain Survey (HLTDS). We find SN spectral energy distributions including prism data carry more information than imaging alone at fixed total observing time, improving redshift measurements and sub-typing of SNe. The Roman field of view will typically include ~ 10 SNe Ia at observable redshifts at a range of phases (the multiplexing of host galaxies is much greater as they are always present), building up SN spectral time series withou…
One major goal of upcoming large-scale-structure surveys is to constrain dark energy and modified gravity theories. In particular, galaxy clustering and gravitational lensing convergence are probes sensitive to modifications of general relativity. While the standard analysis for these surveys typically includes power spectra or 2-point correlation functions, it is known that the bispectrum contains more information, and could offer improved constraints on parameters when combined with the power spectra. However, the use of bispectra has been limited so far to one single probe, e.g. the lensing…
Efficient Optimal Image Reconstruction for the Nancy Grace Roman Space Telescope and Beyond: II. Implementation of {\sc Effortless}
Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University（俄亥俄州立大学宇宙学与暗物质粒子物理中心）；Department of Physics, The Ohio State University（俄亥俄州立大学物理系）
We investigate the possibility that a statistical detection of the galaxy parallax shift due to the Earth's motion with respect to the CMB frame (cosmic secular parallax) could be made by the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) or by the Nancy Grace Roman Space Telescope (NGRST), and used to measure the Hubble constant. We make mock galaxy surveys which extend to redshift z=0.06 from a large N-body simulation, and include astrometric errors from the LSST and NGRST science requirements, redshift errors and peculiar velocities. We include spectroscopic redshifts for …
The Nancy Grace Roman Space Telescope will conduct a High Latitude Spectroscopic Survey (HLSS) over a large volume at high redshift, using the near-IR grism (1.0-1.93 $μ$m, $R=435-865$) and the 0.28 deg$^2$ wide field camera. We present a reference HLSS which maps 2000 deg$^2$ and achieves an emission line flux limit of 10$^{-16}$ erg/s/cm$^2$ at 6.5$σ$, requiring $\sim$0.6 yrs of observing time. We summarize the flowdown of the Roman science objectives to the science and technical requirements of the HLSS. We construct a mock redshift survey over the full HLSS volume by applying a semi-analyt…
This note presents an initial survey design for the Nancy Grace Roman High-latitude Time Domain Survey. This is not meant to be a final or exhaustive list of all the survey strategy choices, but instead presents a viable path towards achieving the desired precision and accuracy of dark energy measurements using Type Ia supernovae (SNe Ia). We describe a survey strategy that use six filters (RZYJH and F) and the prism on the Roman Wide Field Instrument. This survey has two tiers, one "wide" which targets SNe Ia at redshifts up to 1 and one "deep" targeting redshifts up to 1.7; for each, four fi…
Massive stars play critical roles for the reionization of the Universe. Individual massive stars at the reionization epoch (z > 6) are too faint to observe and quantify their contributions to reionization. Some massive stars, however, explode as superluminous supernovae (SLSNe) or pair-instability supernovae (PISNe) that are luminous enough to observe even at z > 6 and allow for the direct characterization of massive star properties at the reionization epoch. In addition, hypothetical long-sought-after PISNe are expected to be present preferentially at high redshifts, and their discovery will …
IRMaGiC: Extending Luminous Red Galaxy Selection into the Infrared with Joint Rubin Observatory's Large Survey of Space Time and Roman's High Latitude Imaging Survey
Duke University（杜克大学）；SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；Stanford University（斯坦福大学）
The cross-correlation between the 21 cm field and the galaxy distribution is a potential probe of the Epoch of Reionization (EoR). The 21 cm signal traces neutral gas in the intergalactic medium and, on large spatial scales, this should be anti-correlated with the high-redshift galaxy distribution which partly sources and tracks the ionized gas. In the near future, interferometers such as the Hydrogen Epoch of Reionization Array (HERA) are projected to provide extremely sensitive measurements of the 21 cm power spectrum. At the same time, the Nancy Grace Roman Space Telescope (Roman) will prod…
We explore synergies between the Nancy Grace Roman Space Telescope and CMB lensing data to constrain dark energy and modified gravity scenarios. A simulated likelihood analysis of the galaxy clustering and weak lensing data from the Roman Space Telescope High Latitude Survey combined with CMB lensing data from the Simons Observatory is undertaken, marginalizing over important astrophysical effects and calibration uncertainties. Included in the modeling are the effects of baryons on small-scale clustering, scale-dependent growth suppression by neutrinos, as well as uncertainties in the galaxy c…
Some million Type Ia supernovae (SN) will be discovered and monitored during upcoming wide area time domain surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). For cosmological use, accurate redshifts are needed among other characteristics; however the vast majority of the SN will not have spectroscopic redshifts, even for their host galaxies, only photometric redshifts. We assess the redshift systematic control necessary for robust cosmology. Based on the photometric vs true redshift relation generated by machine learning applied to a simulation of 500,000 ga…
The High Latitude Survey of the Nancy Grace Roman Space Telescope is expected to measure the positions and shapes of hundreds of millions of galaxies in an area of 2220 deg$^2$. This survey will provide high-quality weak lensing data with unprecedented systematics control. The Roman Space Telescope will survey the sky in near infrared (NIR) bands using Teledyne H4RG HgCdTe photodiode arrays. These NIR arrays exhibit an effect called persistence: charges that are trapped in the photodiodes during earlier exposures are gradually released into later exposures, leading to contamination of the imag…
Towards precision cosmology with Voids x CMB correlations (I): Roman-Agora mock catalogs and pipeline validation
Instituto de Astrofísica de Canarias（加那利天体物理学研究所）；Universidad de La Laguna（拉古纳大学）；MTA–CSFK Lendület “Momentum” Large-Scale Structure (LSS) Research Group（马塔-匈牙利科学院技术研究中心“动量”大尺度结构研究组）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究与创新地球与天文学研究中心）；CPPM, Aix-Marseille Université, CNRS/IN2P3（马赛物理中心，艾克斯-马赛大学，法国国家科学研究中心/法国国家核与粒子物理研究所）；Princeton University（普林斯顿大学）
Diffusion-based Galaxy Simulations for the Roman High Latitude Survey
Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；Duke University（杜克大学）；Department of Physics, California Institute of Technology（加州理工学院物理系）；IPAC, Caltech（加州理工学院红外科学数据中心）
Accurate modeling for 3$\times$2pt analyses in Roman and Rubin: a study of model approximations
University of Chicago（芝加哥大学）；Northeastern University（东北大学）；Stony Brook University（石溪大学）；University of Arizona（亚利桑那大学）；The Ohio State University（俄亥俄州立大学）
The Nancy Grace Roman Space Telescope (RST), with its field of view and high sensitivity will make surveys of cosmological large-scale structure possible at high redshifts. We investigate the possibility of detecting Baryon Acoustic Oscillations (BAO) at redshifts $z>7.6$ for use as a standard ruler. We use data from the hydrodynamic simulation \textsc{BlueTides} in conjunction with the gigaparsec-scale Outer Rim simulation and a model for patchy reionization to create mock RST High Latitude Survey grism data for Lyman-alpha emission line selected galaxies at redshifts $z=7.4$ to $z=10$, cover…
We investigate the performance of the Metacalibration shear calibration framework using simulated imaging data for the Nancy Grace Roman Space Telescope (Roman) reference High-Latitude Imaging Survey (HLIS). The weak lensing program of the Roman mission requires the mean weak lensing shear estimate to be calibrated within about 0.03%. To reach this goal, we can test our calibration process with various simulations and ultimately isolate the sources of residual shear biases in order to improve our methods. In this work, we build on the Roman HLIS image simulation pipeline in Troxel et al. 2021 …
We present and validate 20 deg$^2$ of overlapping synthetic imaging surveys representing the full depth of the Nancy Grace Roman Space Telescope High-Latitude Imaging Survey (HLIS) and five years of observations of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). The two synthetic surveys are summarized, with reference to the existing 300 deg$^2$ of LSST simulated imaging produced as part of Dark Energy Science Collaboration (DESC) Data Challenge 2 (DC2). Both synthetic surveys observe the same simulated DESC DC2 universe. For the synthetic Roman survey, we simulate for th…
Linear Image Regridding and Coaddition with Oversampled Point Spread Functions: Lessons from 1D
Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University（俄亥俄州立大学宇宙学与粒子物理中心）；Department of Physics, The Ohio State University（俄亥俄州立大学物理系）
Space Telescope Science Institute（太空望远镜科学研究所）；Department of Astronomy, University of Wisconsin—Madison（威斯康星大学麦迪逊分校天文学系）；Department of Physics, University of Wisconsin—Whitewater（威斯康星大学惠特沃分校物理系）；SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；The Observatories of the Carnegie Institution for Science（卡内基科学机构天文台）
Current and future generations of intensity mapping surveys promise dramatic improvements in our understanding of galaxy evolution and large-scale structure. An intensity map provides a census of the cumulative emission from all galaxies in a given region and redshift, including faint objects that are undetectable individually. Furthermore, cross-correlations between line intensity maps and galaxy redshift surveys are sensitive to the line intensity and clustering bias without the limitation of cosmic variance. Using the Fisher information matrix, we derive simple expressions describing sensit…
UV luminosity functions provide a wealth of information on the physics of galaxy formation in the early Universe. Given that this probe indirectly tracks the evolution of the mass function of dark matter halos, it has the potential to constrain alternative theories of structure formation. One of such scenarios is the existence of primordial non-Gaussianity at scales beyond those probed by observations of the Cosmic Microwave Background. Through its impact on the halo mass function, such small-scale non-Gaussianity would alter the abundance of galaxies at high redshifts. In this work we present…
