Going Forward with the Nancy Grace Roman Space Telescope Transient Survey: Validation of Precision Forward-Modeling Photometry for Undersampled Imaging
David Rubin, Aleksandar Cikota, Greg Aldering, Andy Fruchter, Saul Perlmutter, Masao Sako
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 perform precision supernova photometry for the Nancy Grace Roman Space Telescope SN survey. Our simulation includes over 760,000 image cutouts around SNe Ia or host galaxies (~ 10% of a full-scale survey). To have a realistic 2D distribution of underlying galaxy light, we use the VELA simulated high-resolution images of galaxies. We run each set of cutouts through our forward-modeling code which automatically measures time-dependent SN fluxes. Given our assumed inputs of a perfect model of the instrument PSFs and calibration, we find biases at the millimagnitude level from this method in four red filters (Y106, J129, H158, and F184), easily meeting the 0.5% Roman inter-filter calibration requirement for a cutting-edge measurement of cosmological parameters using SNe Ia. Simulated data in the bluer Z087 filter shows larger ~ 2--3 millimagnitude biases, also meeting this requirement, but with more room for improvement. Our forward-model code has been released on Zenodo.
The Nancy Grace Roman Space Telescope's (Roman) Coronagraph Instrument is a technology demonstration equipped to achieve flux contrast levels of up to 10$^{-9}$. This precision depends upon the quality of observations and their resultant on-sky corrections via an absolute flux calibration (AFC). Our plan utilizes 10 dim and 4 bright standard photometric calibrator stars from Hubble Space Telescope's (HST) CALSPEC catalog to yield a final AFC error of 1.94\% and total observation time of $\sim$22 minutes. Percent error accounts for systematic uncertainties (filters, upstream optics, quantum eff…
NASA's next flagship mission, the Nancy Grace Roman Space Telescope, is a 2.4-meter observatory set to launch no later than May 2027. Roman features two instruments: the Wide Field Imager and the Coronagraph Instrument. Roman's Coronagraph is a Technology Demonstration that will push the current capabilities of direct imaging to smaller contrast ratios ($\sim$10$^{-9}$) and inner-working angles (3~$λ$/D). In order to achieve this high precision, Roman Coronagraph data must be calibrated to remove as many potential sources of error as possible. Here we present a detailed overview of the Nancy G…
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）
The Coronagraph Instrument (CGI) on the Nancy Grace Roman Space Telescope will demonstrate the high-contrast technology necessary for visible-light exoplanet imaging and spectroscopy from space via direct imaging of Jupiter-size planets and debris disks. This in-space experience is a critical step toward future, larger missions targeted at direct imaging of Earth-like planets in the habitable zones of nearby stars. This paper presents an overview of the current instrument design and requirements, highlighting the critical hardware, algorithms, and operations being demonstrated. We also describ…
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…
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 …
Nancy Grace Roman Space Telescope Wide Field Instrument: Grism Saturation Response to Bright Sources during Thermal-Vacuum Testing
Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Catholic University of America（美国天主教大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Center for Research and Exploration in Space Science and Technology II, NASA/GSFC（美国国家航空航天局戈达德太空飞行中心空间科学与技术研究探索中心II）；University of Maryland, College Park（马里兰大学帕克分校）；KBR（KBR公司）
The Nancy Grace Roman Space Telescope Coronagraph Instrument is a high-contrast imager, polarimeter, and spectrometer that will enable the study of exoplanets and circumstellar disks at visible wavelengths ($\sim$550--850~nm) at contrasts 2--3 orders of magnitude better than can currently be achieved by ground or space-based direct imaging facilities. To capitalize on this sensitivity, precise flux calibration will be required. The Roman Coronagraph, like other space-based missions, will use on-orbit flatfields to measure and correct for phenomena that impact the measured total effective throu…
Prospects for Reconstructing the Free-floating Planet Mass Function at the Population Level with the Nancy Grace Roman Space Telescope
University of Maryland, College Park（马里兰大学帕克分校）；The Johns Hopkins University（约翰斯·霍普金斯大学）；NASA Jet Propulsion Laboratory（美国宇航局喷气推进实验室）；The Ohio State University（俄亥俄州立大学）；Louisiana State University（路易斯安那州立大学）；Space Science Institute（空间科学研究所）
The shear signal required for weak lensing analyses is small, so any detector-level effects which distort astronomical images can contaminate the inferred shear. The Nancy Grace Roman Space Telescope (Roman) will fly a focal plane with 18 Teledyne H4RG-10 near infrared (IR) detector arrays; these have never been used for weak lensing and they present unique instrument calibration challenges. A pair of previous investigations (Hirata & Choi 2020; Choi & Hirata 2020) demonstrated that spatiotemporal correlations of flat fields can effectively separate the brighter-fatter effect (BFE) and interpi…
The Nancy Grace Roman Space Telescope Coronagraph Community Participation Program
Cornell University（康奈尔大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；The University of Arizona（亚利桑那大学）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；Northwestern University（西北大学）；Aix Marseille Univ, CNRS, CNES, LAM（艾克斯马赛大学）；Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité（巴黎天文台）；University of Edinburgh（爱丁堡大学）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；Arizona State University（亚利桑那州立大学）；SRON Netherlands Institute for Space Research（荷兰空间研究研究所）；Space Telescope Science Institute（太空望远镜科学研究所）；Caltech（加州理工学院）；Massachusetts Institute of Technology（麻省理工学院）；University of California, Riverside（加州大学河滨分校）；Princeton University（普林斯顿大学）；Astrobiology Center, NINS（日本天体生物学中心）；National Astronomical Observatory of Japan（日本国立天文台）
The Nancy Grace Roman Space Telescope (Roman) will perform a Galactic Exoplanet Survey (RGES) to discover bound exoplanets with semi-major axes greater than 1 au using gravitational microlensing. Roman will even be sensitive to planetary mass objects that are not gravitationally bound to any host star. Such free-floating planetary mass objects (FFPs) will be detected as isolated microlensing events with timescales shorter than a few days. A measurement of the abundance and mass function of FFPs is a powerful diagnostic of the formation and evolution of planetary systems, as well as the physics…
We present design considerations for the Transiting Exosatellites, Moons, and Planets in Orion (TEMPO) Survey with the Nancy Grace Roman Space Telescope. This proposed 30-day survey is designed to detect a population of transiting extrasolar satellites, moons, and planets in the Orion Nebula Cluster (ONC). The young (1-3 Myr), densely-populated ONC harbors about a thousand bright brown dwarfs (BDs) and free-floating planetary-mass objects (FFPs). TEMPO offers sufficient photometric precision to monitor FFPs with ${\rm M}\geq1{\rm M}_{\rm J}$ for transiting satellites. The survey is also capabl…
The Nancy Grace Roman Space Telescope Wide Field Instrument: Characterization of the Brighter-Fatter Effect in a Roman H4RG-10 Detector using the Talbot Effect
University of Maryland, Baltimore County（马里兰大学巴尔的摩县分校）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Center for Research and Exploration in Space Science and Technology（空间科学与技术研究探索中心）；Space Telescope Science Institute（太空望远镜科学研究所）
The Roman Coronagraph Community Participation Program: corgisim - a simulation suite for the Nancy Grace Roman Space Telescope Coronagraph Instrument
University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；Aix Marseille Université（艾克斯-马赛大学）；Northwestern University（西北大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；DM Telescopes LLC（DM望远镜有限责任公司）；University of Alabama at Huntsville（阿拉巴马大学亨茨维尔分校）；National Astronomical Observatory of Japan（日本国立天文台）；Space Telescope Science Institute（空间望远镜科学研究所）；California Institute of Technology（加州理工学院）
Reflected starlight measurements will open a new path in the characterization of directly imaged exoplanets. However, we still lack a population study of known targets amenable to this technique. Here, we investigate which of the about 4300 exoplanets confirmed to date are accessible to the Roman Space Telescope's coronagraph (CGI) in reflected starlight at reference wavelengths $λ$=575, 730 and 825 nm. We carry out a population study and also address the prospects for phase-curve measurements. We used the NASA Exoplanet Archive as a reference for planet and star properties, and explored the i…
Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. V. Detection Rates of Multiplanetary Systems in High Magnification Microlensing Events
Nancy Grace Roman Space Telescope Wide Field Instrument: Bright Point Source Saturation Response and Persistence Properties from Thermal-Vacuum Testing
Catholic University of America（天主教大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；University of Maryland, College Park（马里兰大学帕克分校）；ADNET Systems, Inc.（ADNET系统公司）；KBR（KBR公司）
Roman CCS White Paper: Tracing stellar mass assembly and emerging quiescence at cosmic noon -- the case for deep imaging with all of Roman's wide filters in the HLTDS
本文论证了在 Roman 望远镜 HLTDS 中使用除 F146 外所有宽滤光片进行深度成像的必要性，以推动河外深场科学并改进 SN Ia 宇宙学系统学。
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…
The Nancy Grace Roman Space Telescope Coronagraph Instrument will be the first large scale coronagraphmission with active wavefront control to be operated in space and will demonstrate technologies essential tofuture missions to image Earth-like planets. Consisting of multiple coronagraph modes, the coronagraph isexpected to characterize and image exoplanets at 1E-8 or better contrast levels. An object-oriented physicaloptics modeling tool called POPPY provides flexible and efficient simulations of high-contrast point spreadfunctions (PSFs). As such, three coronagraph modes have been modeled i…
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）
The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) will be capable of characterizing exoplanets in reflected light and will demonstrate space technologies essential for future missions to take spectra of Earthlike exoplanets. As the mission and instrument move into the final stages of design, simulation tools spanning from depth of search calculators to detailed diffraction models have been created by a variety of teams. We summarize these efforts, with a particular focus on publicly available datasets and software tools. These include speckle and point-spread-function models, …
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 …
Simultaneous observations from two spatially well-separated telescopes can lead to the measurements of the microlensing parallax parameter, an important quantity toward the determinations of the lens mass. The separation between Earth and Sun-Earth L2 point, $\sim0.01$ AU, is ideal for parallax measurements of short and ultra-short ($\sim$1\,hr to 10\,days) microlensing events, which are candidates of free-floating planet (FFP) events. In this work, we study the potential of doing so in the context of two proposed space-based missions, the Chinese Space Station Telescope (CSST) in a Leo orbit …
Microlens parallax measurements combining space-based and ground-based observatories can be used to study planetary demographics. In recent years, the Spitzer Space Telescope was used as a microlens parallax satellite. Meanwhile, \textit{Spitzer} IRAC has been employed to study short-period exoplanets and their atmospheres. As these investigations require exquisite photometry, they motivated the development of numerous self-calibration techniques now widely used in the exoplanet atmosphere community. Specifically, Pixel Level Decorrelation (PLD) was developed for starring-mode observations in …
Initial Characterization of Stellar Photometry of Roman images from the OpenUniverse Simulations
Duke University（杜克大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Baylor University（贝勒大学）；University of Maryland Baltimore County（马里兰大学巴尔的摩县分校）；NASA GSFC（NASA戈达德太空飞行中心）
We present and validate 20 deg$^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…
Jointly Modeling Roman Coronagraph Astrometry and Photometry Improves Orbital Parameter Estimates
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University（西北大学跨学科天体物理探索与研究中心）；Department of Physics and Engineering, University of St. Thomas（圣托马斯大学物理与工程系）；Department of Astronomy and Astrophysics, University of California, Santa Cruz（加州大学圣克鲁斯分校天文与天体物理系）
This document summarizes how far the Nancy Grace Roman Space Telescope Coronagraph Instrument (Roman CGI) will go toward demonstrating high-contrast imaging and spectroscopic requirements for potential future exoplanet direct imaging missions, illustrated by the HabEx and LUVOIR concepts. The assessment is made for two levels of assumed CGI performance: (i) current best estimate (CBE) as of August 2020, based on laboratory results and realistic end-to-end simulations with JPL-standard Model Uncertainty Factors (MUFs); (ii) CGI design specifications inherited from Phase B requirements. We find …
