The Nancy Grace Roman Space Telescope is a NASA flagship mission planned for launch no later than May 2027. The Roman Space Telescope will perform breakthrough science in dark energy cosmology, exoplanet microlensing, and NIR sky surveys with its Wide Field Instrument. Roman will also feature the Coronagraph Instrument (CGI), a technology demonstration that will directly image and take spectra of exoplanetary systems using several novel technologies together for the first time in space. This session will cover the status of the project and upcoming opportunities for community involvement in planning and executing the science and technology demonstration aspects of Roman.
The Nancy Grace Roman Space Telescope will be conducting a major space base extra galactic time domain survey. The influx of data will require new data analysis techniques. Come to this first community input session hosted by the Roman SN Project Infrastructure Team (PIT). Learn about what this PIT is planning, how you can get involved and let your feature requests be heard. We will discuss simulations, calibration, photometry, spectroscopy and supernova cosmology pipelines.
With a Wide Field Imager (WFI) delivering Hubble-like resolution over roughly 100 times the instantaneous area, and an observatory designed to enable large-area surveys nearly three orders of magnitude faster than HST, the Nancy Grace Roman Space Telescope will produce expansive surveys that transform our understanding of dark energy, dark matter, galaxies, and exoplanets. In order to help plan for and take full advantage of the Roman surveys, as well as test data reduction and analysis algorithms currently being developed, it is essential to create detailed simulated Roman photometric, morphological and spectroscopic datasets. The start of the community process of defining Roman's Core Community Surveys, preparations for launch in late 2026 and the expected release of the first public data in early 2027 make this a timely topic for discussion. This session will bring together observers and theorists to discuss and plan for simulations to maximize the scientific return from Roman’s Core Community and General Astrophysics surveys.
The Nancy Grace Roman Space Telescope's Wide Field Instrument (WFI) will have a large field of view (0.28 sq deg), Hubble-like sensitivity and resolution, and highly efficient survey operations. Roman's WFI observing program will include both Core Community Surveys and General Astrophysics surveys, defined by a combination of a community-led process and traditional peer-reviewed calls for proposals. The Core Community Surveys will include a High Latitude Wide Area survey, a High Latitude Time Domain survey, and a Galactic Bulge Time Domain survey. In addition to addressing Roman's science requirements related to cosmology and exoplanet demographics, the science community has described an exciting range of science investigations that can be undertaken with data from these surveys, given appropriate observational strategies (https://roman.gsfc.nasa.gov/science/ccs_community_input.html). The community-led effort to define Roman's Core Community Surveys is now underway, with the formation of the committees charged with defining the Core Community Surveys and their review of the science community's initial input. The purpose of this session is to provide attendees with an opportunity to engage with the definition committees for each survey on the prioritization of science drivers for survey definition and the identification of the most promising scientific synergies amongst the various science drivers. The session will include an introduction to each of the Core Community Survey definition committees and an overview of each committee's progress and plans, with the majority of the time reserved for discussion and community input. Approximately one-third of the time will be dedicated to each Core Community Survey. A detailed schedule for the Splinter Meeting will be available at the STScI, IPAC, and NASA booths.
Set to launch in late 2026, the Roman Space Telescope is designed to open entirely new doors in the fields of cosmology and exoplanet demographics as part of its planned Core Community Surveys. However, the combination of Roman’s astrometric precision, survey sensitivity, and mapping speed also make it ideally suited for surveying broad swaths of the Milky Way’s disk. Uniformly surveying the Galactic plane and bulge with Roman would significantly expand its scientific impact in the fields of stellar populations, star formation, the interstellar medium, and Galactic structure and dynamics, among many others. Roman holds the potential to image tens of billions of stars in heavily dust-enshrouded regions across the Milky Way, enabling dramatic Galactic science with even a single epoch. With multiple epochs, Roman can obtain proper motions, complementing Gaia in heavily-obscured and/or confused regions and acting as a precursor for a potential near-infrared Gaia mission. In this special session, we will bring together the community interested in General Observer investigations of the Milky Way plane with Roman to highlight the broad range of Galactic science cases and outline the survey design factors (coverage, filters, epochs) necessary to achieve them. Attendees will gain an understanding of i) current efforts to design and implement a Galactic plane survey with Roman, ii) the synergies between Roman and complementary photometric, astrometric, and spectroscopic surveys of the plane on the horizon, and iii) ways to be involved in community-driven efforts for organizing a Roman Galactic plane survey. In addition to a series of short talks by subject matter experts, the session will include a thirty minute panel discussion with attendees.
Oral Session Talks
The Roman Photometric Repeatability Floor - L. Aldoroty (Duke U.) et al.
(Tuesday, January 9, 2:50–3:00 p.m. CT)
NASA’s Nancy Grace Roman Space Telescope (Roman) will provide an opportunity to study dark energy with unprecedented precision using several probes. Type Ia Supernovae are a key part of dark energy studies; as standardizable candles, they are used to construct the cosmological distance ladder. However, there are only approximately 20 SNe Ia with sufficiently well-sampled light curves above z > 1. Roman will change the landscape of SN Ia-driven dark energy studies by discovering enough SNe Ia at z > 1 to render statistical uncertainties insignificant. In order to make the best use of these observations, photometric measurements should be repeatable and precise between images. Roman’s expected photometric precision is <1%, and a factor of 10 better than HST. In this work, we use the GALSIM-derived Roman simulations from Wang et al. (2023) to determine the photometric repeatability floor for the High-Latitude Time Domain Survey. We perform photometry on field stars in these images, and show that the Roman repeatability floor will meet expectations.
Cosmic ray detection for the Roman Wide Field Instrument - S. Sharma (STScI) et al.
(Wednesday, January 10, 10:20–10:30 a.m. CT)
We investigate algorithms to detect and correct jumps caused by cosmic rays in infrared detectors, with emphasis on the Roman telescope's Wide Field Instrument (WFI). We use a statistic based on the excess difference between adjacent resultants (averaged over a group of reads) normalized to the square root of the expected variance, which takes into account the uneven resultants expected to be used in WFI reading patterns. We show that it is important to account for the covariance of excess difference with that of the estimated count rate. Averaging reads reduces the ability to detect jumps, especially when they occur in the first or last readings. Configuring the reading patterns so that the first and last resultants are single-reads enhances our ability to detect cosmic rays. We also investigate bias and the false negative rate using Monte Carlo simulations for various readout patterns. To explore other scenarios, we present approximate formulas for predicting bias and the misclassification rate. Using cosmic ray properties based on JWST darks, we demonstrate that at high count rates (1000 electrons/s), most cosmic rays go undetected, resulting in 65% missed identifications. When averaging over multiple exposures, the overall bias in the estimated count rate due to undetected cosmic rays is negligible. However, for a single exposure, there can be a bias of a few percent, with the bias in the count rate about 1 to 5 times its expected uncertainty. This finding has implications for scientific applications that seek to identify rare, abrupt changes in the brightness of targets.
The Allure of 200,000 Transiting Exoplanets in the Roman Galactic Bulge Time Domain Survey - R.F. Wilson, E. Quintana (NASA GSFC)
(Wednesday, January 10, 3:20–3:30 p.m. CT)
The Nancy Grace Roman Space Telescope, NASA's next flagship mission scheduled to launch in late 2026, will conduct a high-cadence, time-series survey of an approximately 2 square degree field near the Galactic bulge. Due to the high stellar densities and depth of observations, this survey is expected to discover 60,00-200,000 transiting exoplanets. The allure of this sample is threefold: First in the unprecedented statistical power offered by an order of magnitude increase in sample size, second in the diversity of stellar populations surveyed, and finally in the use of a Near-IR bandpass where planet-star contrast ratios are reduced. The combination of these effects will enable a myriad of new science investigations in transiting planets, including an in-depth measurement of the Galactic exoplanet distribution, a census of Jupiter-sized planets with orbital distances out to several AU, and the first systematic study of 1000s of homogeneously detected exoplanet atmospheres.
Population Survey and Image Simulation of Strong Gravitational Lenses Detectable by the Roman Space Telescope - B. Wedig, T. Daylan (Washington U. St. Louis)
(Thursday, January 11, 2:50–3:00 p.m. CT)
We present a population survey and simulated images of galaxy-galaxy strong gravitational lenses detectable by the Nancy Grace Roman Space Telescope (hereafter, Roman). Strong gravitational lensing is a powerful tool for constraining dark matter models and the Lambda Cold Dark Matter cosmological model at sub-galactic scales. Dark matter substructure in the foreground galaxy can be detected by forward-modeling methods and Bayesian convolutional neural networks. Sensitivity to lower mass scales ($<10^{11} M_\odot$) depends on high angular resolution, signal-to-noise, and the separation of background galaxy arcs and foreground galaxy light. Roman, scheduled for launch in late 2027, will play a crucial role in strong lensing science in conjunction with upcoming wide-field surveys such as the Rubin Observatory's LSST and those by the Euclid Space Telescope. It is uniquely suited to characterizing dark matter substructure in strong lenses with its high, diffraction-limited angular resolution of 0.1 arcseconds and point-source sensitivity of 27.9-25.4 in 1 hour across its eight filters. We utilize \verb|SkyPy| to simulate a population of strong lenses across cosmic time. We consider a random distribution of early- and late-type galaxies out to redshift $z=4$ and identify strong lenses based on their alignment along our line of sight. Then, we determine the subset detectable by Roman and those amenable to characterization. We generate realistic pipeline-processed simulated images of galaxy-galaxy strong lenses to be taken by Roman's Wide Field Instrument based on our population survey. We utilize the Space Telescope Image Product Simulator (\verb|STIPS|) maintained by the Space Telescope Science Institute, which models instrumental noise and residual errors. An accurate yield simulation with associated images of strong lenses will support future strong lens science with Roman.
iPoster-Plus Sessions
The Astronomer's Proposal Tool for the Roman Space Telescope - M. Mutchler (STScI) et al.
(Tuesday, January 9, 9:00–10:00 a.m. CT WITHDRAWN)
The Astronomer's Proposal Tool (APT) is familiar to scientists who design and submit General Observer (GO) proposals for Hubble and JWST. APT now also allows for the design of observing proposals for the Wide Field Instrument (WFI) of the Nancy Grace Roman Space Telescope. Roman has a planned launch in late 2026, with a 5-year primary mission and a possible 5-year extension. The majority of the first five years will be dedicated to Core Community Surveys (CCS), which are being defined by a community-led process (see the splinter session). General Astrophysics Surveys (GAS) will also be solicited via calls for proposals, and peer-reviewed, to complete the science program. Roman APT includes a new hierarchy for designing large surveys, which Roman can conduct very efficiently with fast slews and a field-of-view which is 200 times bigger than Hubble's infrared camera. It also includes tools for designing mosaics and large region targets, and eventually on-sky visualizations in Aladin. Templates for common use cases will be available in the APT menu. The Roman APT Users Guide (RAUG) is available in the Roman Documentation System (RDox), and questions or feedback can be sent to the new Roman helpdesk portal at STScI.
Sky background matching in Roman WFI mosaics - D. Fadda (STScI) et al.
(Tuesday, January 9, 5:30–6:30 p.m. CT)
The Wide Field Instrument (WFI) on the Roman Space Telescope will have an unprecedented field of view for a space telescope, roughly 100 times greater than HST or JWST. Since it will perform several surveys of large areas of the sky, it will be essential to match the background of overlapping images in order to coadd them into seamless mosaics. Variations in the background caused by cosmic rays, baseline drifts occurring during long integrations, and different zodiacal light contribution for observations in different time of the year can, in fact, lead to background offsets among different images of the same field. To avoid discontinuities in the final mosaic which could hinder the detection of faint diffuse structures it is therefore imperative to mitigate these effects by adjusting the image backgrounds in a statistical sense. We present here a study of different algorithms used for sky background matching and discuss their applicability to WFI mosaics.
Automated Anomaly Detection at Scale With the Cloud-Based Roman Data Monitoring Tool - O. J. Otor (STScI) et al.
(Tuesday, January 9, 5:30–6:30 p.m. CT)
The Nancy Grace Roman Space Telescope (Roman) is an upcoming NASA flagship mission that is planned for launch no later than 2027. Roman is primarily a survey mission with the Wide Field Instrument (WFI) as its main instrument. The WFI consists of eighteen 16-megapixel detectors and is anticipated to produce 20 PB of science data during its five-year primary mission, an order of magnitude more than the current and planned yields of all active NASA flagship missions in astrophysics. Given that amount of data, the Roman Science Operations Center is developing the Roman Data Monitoring Tool, a scalable, cloud-based platform built to automate the anomaly detection process in WFI science observations. We present its prototype astrometric monitor, which automatically processes calibrated Roman WFI images, performs point spread function (PSF) photometry, computes astrometric offsets against a guide star catalog, and logs the results to a database. Additional monitors are currently under development to enable instrument scientists to triage data by monitoring PSF shape and stability, background and detector bias levels, and other image quality metrics.
Simulating 3D Galaxy Datacubes for the Roman Space Telescope - J. Gong, M. Sako (UPenn)
(Tuesday, January 9, 5:30–6.30 p.m. CT)
One of the Nancy Grace Roman Space Telescope’s primary goals is to illuminate the nature of dark energy, which may explain the acceleration of the expansion of the universe. A particularly useful tool to estimate this acceleration is Type Ia Supernovae, but telescope observations of these supernovae are contaminated by their host galaxies. As a result, it is imperative to obtain clean supernova spectra by subtracting the host galaxy spectrum from the observed (SN+galaxy) spectrum. This galaxy spectrum can be simulated for various cosmological redshifts, using Sloan Digital Sky Survey imaging data to generate model spectra stored in datacubes. To construct the synthetic Roman datacube, we develop a pipeline involving the resampling, cutting, and cleaning of SDSS ugriz images, the modeling of a continuous spectral energy distribution (SED) using CIGALE, and the redshifting, dimming, and resampling of the galaxy according to Roman parameters. We finally employ Gaussian smoothing to eliminate unphysical discontinuities in the SEDs across pixels of the datacube. Results indicate that every pixel within the galaxy has a slightly different model SED, which is to be expected. Similarly, the galaxy varies in appearance over the wavelength frames, yet remains realistic within Roman’s wavelength range. In summary, simulated Roman galaxy datacubes generated for any user-defined redshift will be used for the extraction of clean SNe Ia spectra from future Roman observations. Ultimately, better modeling and standardization of SNe Ia light curves is crucial to more accurately estimating dark energy parameters – thus mapping out with greater precision the detailed expansion history of the universe.
The Roman Space Telescope Science Operations Center: News and updates - S. Gomez (STScI) et al.
(Wednesday, January 10, 5:30–6:30 p.m. CT)
NASA’s next flagship missing, The Nancy Grace Roman Space Telescope (Roman), is planned for launch in October 2026. The Science Operations Center (SOC) for Roman is located at the Space Telescope Science Institute (STScI) in Baltimore, MD. The Wide Field Imager (WFI) onboard Roman provides HST-like spatial resolution across wavelengths ranging from 0.48 to 2.3 microns and spans a field of view of 0.271 sq. deg. With a field of view approximately 200 times larger than WFC3/IR on HST, WFI will produce data rates 500 times larger than all instruments on HST and 23 times larger than all instruments on JWST. The SOC is responsible for developing the Roman planning and scheduling system, the data processing system for WFI imaging data, and the data archive for the whole mission. The SOC will produce additional data products for WFI imaging, including catalog-level products. Here we provide an overview of the SOC and present updates to its contributions to the Roman mission, including recent technical reports, updates to simulation tools, and the SOC Helpdesk.
The Roman Space Telescope Science Operations Center: the SOC Roman Documentation (RDox) Platform - R. Beaton (STScI) et al.
(Wednesday, January 10, 5:30–6:30 p.m. CT)
RDox is the documentation platform for the Roman Space Telescope Science Operations Center (SOC) at STScI. The latest RDox release contains draft versions of the Roman APT User’s Guide (RAUG), the imaging portion of the Wide Field Instrument Handbook, the SOC Simulation Tools Handbook, and the Data Handbook describing data processing up to L2.Content for RDox is being developed prior to launch, with a primary focus on providing essential information for community engagement in the mission. While the documentation for spectroscopic observations and the Coronograph will be developed by the Science Support Center at IPAC, RDox is designed to provide a seamless experience to the users. This contribution will describe the technical implementation of RDox using Atlassian’s Confluence, customized components developed at STScI, accessibility features to broaden participation, summaries of current holdings, and a high-level development schedule.
Prospects for Detecting Gaps in Globular Cluster Stellar Streams in External Galaxies with the Nancy Grace Roman Space Telescope - C. Aganze (Stanford) et al.
(Wednesday, January 10, 5:30–6:30 p.m. CT)
Stellar streams form through the tidal disruption of satellite galaxies or globular clusters orbiting a host galaxy. Globular cluster streams are exciting since they are thin (dynamically cold) and, therefore sensitive to perturbations from low-mass subhalos. Since the subhalo mass function differs depending on the dark matter composition, these gaps can provide unique constraints on dark matter models. However, current samples are limited to the Milky Way. With its large field of view, deep imaging sensitivity, and high angular resolution, the upcoming Nancy Grace Roman Space Telescope presents a unique opportunity to increase the number of observed streams and gaps significantly. In this work, we present a first exploration of the prospects for detecting gaps in streams in M31 and other nearby galaxies with resolved stars. We simulate the formation of gaps in a Palomar-5-like stream and generate mock observations of these gaps with background stars in M31 and the foreground Milky Way stellar fields. We assess Roman's ability to detect gaps out to 10 Mpc through visual inspection and with the gap-finding tool (FindTheGap, Contardo et al. 2022). We conclude that gaps with sizes of ~1.5 kpc in streams that are created from subhalos of masses >5x10^6 Msun are detectable within a 2-5 Mpc volume in exposures of 1000s to 1 hour. Large samples of stream gaps in external galaxies will open up a new era of statistical analyses of gap characteristics in stellar streams and help constrain dark matter models.
Simulating Weak Gravitational Lensing in the Roman Space Telescope Using JWST Observed Galaxies - A. Barnes (UMaryland), A. Choi (NASA GSFC)
(Wednesday, January 10, 5:30–6:30 p.m. CT)
Some of the most perplexing mysteries of our Universe are connected to the energy and matter we have been unable to physically observe. Making up about 95% of the Universe, dark energy and dark matter do not emit, absorb, nor reflect any portion of the electromagnetic spectrum, and their existence is only inferred through their effects on the visible matter. For example, gravitational lensing is a phenomenon that refers to the magnification and shearing induced on light from distant galaxies caused by the gravitational potential of foreground matter. The amount of lensing is directly related to the total amount of matter present, not just the matter that emits light. Weak gravitational lensing, when these distortions are not as noticeable, allows for the entirety of the “cosmic web”, or large-scale structure, to be probed during dark matter searches instead of just the areas we know are dense with matter i.e. galaxy clusters. In order to properly measure weak lensing effects, accurate galaxy shape measurements that can be calibrated with simulations are required. The Nancy Grace Roman Space Telescope is the next upcoming NASA flagship mission. One of its main goals is elucidating the nature of dark matter and dark energy via ultra-wide field UV-NIR imaging surveys. Roman’s view is 100 times that of the Hubble Space Telescope, and we will be primed to measure large-scale structure in the context of weak lensing studies.In this poster, I will present our efforts to simulate JWST observed galaxies through the eyes of Roman. I will detail how we remove the PSF from a JWST NIRCam imaged galaxy, and add Roman filters and detector effects. We report the comparison between JWST and simulated Roman imaging, and place our results in the context of future weak lensing searches with Roman.
Non-Linearity Correction Methods for The Roman Space Telescope - A. Petric (STScI) et al.
(Thursday, January 11, 1:00–2:00 p.m. CT)
The Nancy Grace Roman Space Telescope (Roman) is NASA's next flagship mission, planned to launch in late 2026. The Wide Field Instrument (WFI) on Roman will provide a field of view 200 times larger than Hubble's WFC3/IR camera, with comparable sensitivity and spatial resolution. Combining its field of view with its incredible survey speed, Roman will perform near-IR imaging and spectroscopic surveys 1000 times faster than the largest surveys from Hubble. Roman’s legacy will be shaped by unmatched survey accuracy, which requires careful photometric and astrometric calibrations. The WFI H4RG detectors have superb noise properties and low dark current but are inherently non-linear in response to incident photons. Here, we focus on a crucial calibration step: linearization. We present and compare several methods for correcting non-linearity using polynomial fits, principal component analysis, and machine learning techniques.
Verification and Calibration of Spectroscopy and Polarization modes for the Roman Coronagraph Instrument - T. Groff (NASA GSFC) et al.
(Thursday, January 11, 1:00–2:00 p.m. CT)
As part of its technology demonstration, the Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) will demonstrate point source spectroscopy and polarization measurements of disks. The spectroscopy mode is a zero-deviation Amici prism and slit to a confirmed planet after an imaging detection. The Wollaston prism polarization optics allow for imaging two orthogonal polarization states simultaneously. The CGI spectral characterization modes, designed and built at Goddard Space Flight Center (GSFC), have a spectral resolution of R50 in two 15% bandpass centered at 660nm and 730nm intended to capture key methane absorption features. There are duplicate Wollaston prism channels, clocked 45 degrees with respect to one another covering 10% bandpasses at 575 and 825nm, but the optics meet performance requirements across the full CGI bandpass. The Wollaston design and optical elements are a contribution by the Japanese Aerospace Exploration Agency, with final alignment and testing being done at GSFC. We highlight the requirements for these modes, the ground-to-orbit calibration process, and the operations required to use a deployable slit on a CGI point source in the presence of pointing error. We also provide further detail on the optomechanical design, testing results from the final as-built flight units, verification process, and performance of the as-built flight assemblies.
Spot-Based Measurement of the Brighter-Fatter Effect on a Roman Space Telescope H4RG Detector and Comparison with Flat-Field Data - A. Plazas Malagon (SLAC) et al.
(Thursday, January 11, 1:00–2:00 p.m. CT)
We present the measurement and characterization of the brighter-fatter effect (BFE) on a NASA Roman Space Telescope development Teledyne H4RG-10 near-infrared detector using laboratory measurements with projected point sources. After correcting for other interpixel non-linearity effects such as classical non-linearity and inter-pixel capacitance, we quantify the magnitude of the BFE by calculating the fractional area change per electron of charge contrast. We also introduce a mathematical framework to compare our results with the BFE measured on similar devices using autocorrelations from flat-field images. We find an agreement of 18 ± 5% between the two methods. We identify potential sources of discrepancy and discuss future investigations to characterize and address them.
NASA Hyperwall Talks (NASA exhibit)
Great [missions] are not maintained by timidity! - Dominic Benford (NASA GSFC)
(Sunday, January 7, 7:30–7:45 p.m. CT)
The Nancy Grace Roman Space Telescope is coming to fruition – with launch expected in around three years, scientists from around the world are preparing for the mission with simulations and analysis tools, and engineers are working to complete all the major hardware systems in 2024. It's an exciting time to get in on the ground floor of this transformative observatory!
Coronagraph Technology Demo on the Roman Space Telescope - Rob Zellum (NASA JPL)
(Tuesday, January 9, 9:20-9:35 a.m. CT)
TBD abstract.
The Dynamic Sky with NASA's Roman Space Telescope - Ori Fox (STScI)
(Thursday, January 11, 9:35-9:50 a.m. CT)
Exploring transient and time-domain science with Roman, including a plug for the Core Community Surveys encouraging the community to get involved.
Obscured AGN with Roman–-Hiding High Growth across Cosmic Time - Andreea Petric (STScI)
(Wednesday, January 10, 9:05-9:20 a.m. CT)
Galaxies with active black holes in their nuclei (active galactic nuclei or AGN) that are fully or partially hidden by dust and gas may evolve differently than non-obscured AGN. Roman's wide field photometric and spectroscopic capabilites will be crucial for measuring the physical processes that may be responsible for this different evolution as a function of mass and environment. I will also discuss how to leverage the synnergies between Roman and other space and ground facilities to learn about obscured AGN populations.
Roman Science Operations Center updates - Rachael Beaton (STScI)
(Thursday, January 11, 1:30-1:45 p.m. CT)
From Photons at the Telescope to science discoveries -- What the Roman SOC does and where we are in doing it. Lots of glamour shots of the WFI instrument, the data flow (from space to the ground), what some simulated data looks like, and how users will iteract with Roman data.
Roman Wide Field Instrument: From ground tests to science - Amethyst Barnes (NASA GSFC)
(Thursday, January 11, 9:50-10:05 a.m. CT)
Connect the hardware to the science via some examples of recent test performance (e.g., from the recently completed WFI TVAC1 campaign).
