Roman Space Telescope at the 241st AAS Meeting

January 8-12, 2023 (Seattle, Hybrid Meeting)

Town Hall: Nancy Grace Roman Town Hall

  • Nancy Grace Roman Town Hall
    (Tuesday, January 10, 6:30–7:30 p.m. PST)

    The Nancy Grace Roman Space Telescope (formerly known as WFIRST) is a NASA flagship mission planned for launch in the mid 2020s. 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.

Oral Splinter Sessions

  • Nearby Galaxies under a New Light with Roman
    (Monday, January 9, 1:00–3:00 p.m. PST)

    The Roman Space Telescope will provide HST-like spatial resolution in the optical and near-infrared, but with a field of view 100 times larger than HST. Even for single pointings, this provides data sets comparable to large survey projects with previous generation space-based observatories. Roman's large field-of-view will also quickly map the most nearby galaxies with resolved stars. Its superb astrometric capabilities will allow us to measure galaxy growth across space and time with unprecedented detail. Complementary, studies that map stellar populations with Roman in the most nearby galaxies will teach us valuable lessons to connect to observations and simulations of the early Universe. ALMA and JWST studies of galaxies probe the build-up of stellar mass at high redshift and, in complement, Roman will provide statistically significant samples to study how efficient metal production is during the most vigorous stages of galactic growth. The goal of this session is to bring together expertise from the local and more distant Universe to articulate how studies of the expanding horizon of the nearby Universe, with Roman, can be connected to our understanding of the most distant objects.

  • Starting Now: Community-Led Definition of the Roman Core Community Surveys
    (Wednesday, January 11, 2:00–3:30 p.m. PST)

    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 blistering survey speeds: the Roman Space Telescope will be capable of performing the equivalent of Hubble's largest surveys roughly 1000 times faster. 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, respectively. The Core Community Surveys (CCSs) 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 the Roman Mission's science requirements related to cosmology and exoplanet demographics, the data from the CCSs will enable a host of general astrophysical investigations. The Roman Mission is intent on engaging the broad astronomical community in defining the CCSs in a way that will maximize their expansive scientific impact. This effort is starting now, with a call for white papers from the community planned for release in late 2022. The goal of the white paper call is to solicit from the community descriptions of specific scientific investigations that can be achieved with the CCSs, the observational strategies that will enable these investigations to be performed with a given CCS, and the figures of merit that can be used to assess whether an observational strategy will enable a particular investigation. The purpose of this special session is to provide attendees the information they need to write effective white papers, and to receive feedback from attendees on the planned community process for defining the CCSs. The session will include updates on the status of the Mission relevant to defining the core surveys, an overview of the community-driven process for defining the CCSs, a discussion of the observational parameter spaces under consideration for each CCS, a question and answer session, and the opportunity to provide feedback. Attendees will obtain the information necessary to produce informative, influential white papers, which in turn will be used to guide community-led definition of the observing strategies of the three Roman Core Community Surveys. Attendance of this splinter will be your first step to help ensure that Roman will obtain its survey data in a manner that is optimal for your science interests.

  • The Future of Transient Science With the Roman Space Telescope
    (Wednesday, January 11, 6:30–8:30 p.m. PST)

    The Nancy Grace Roman Space Telescope will be launched by mid 2027 and is tasked with answering three major questions; what is dark matter, what is dark energy, and what are the properties of exoplanets. These questions will be answered through the use of Roman’s Wide Field Instrument which will facilitate deep, high cadence, near-infrared imaging and spectroscopy of many square degrees of the night sky. During this session, we aim to explore all areas of transient science that could be achieved using the Roman Space Telescope. We will discuss several key areas of transient science, how future Roman observations will expand our understanding of transients, and how the various Roman monitoring observations could be tailored to better constrain their properties. Presentations include: Studying Core-Collapse Supernovae and their Progenitors with the Roman Space Telescope, Azalee Bostroem (U. Arizona); Observing the Diversity of Neutron Star Merger Counterparts with Roman, Jillian Rastinejad (Northwestern); Revealing Hidden Cataclysms in Compact Binaries: Prospects with the Roman Space Telescope, Kishalay De (MIT); Discovering Supernovae at the Epoch of Reionization with the Nance Grace Roman Space Telescope, Takashi Moriya (NAOJ). The session will conclude with an open discussion on how we can continue to prepare for the detection and study of a diverse range of transient science with Roman.

Oral Session Talks

  • Multi-Star Wavefront Control: Update on Technology Development for Roman Space Telescope and IR/O/UV - D. Sirbu (NASA Ames) et al.
    (Monday, January 9, 2:10–2:20 p.m. PST)
    A majority of Sun-like stars have at least one stellar companion that can introduce additional noise into the field of view of any high-contrast imaging instrument, limiting the achievable contrast. These include high-quality target stars such as the A and B components of Alpha Centauri, our nearest stellar neighbor. Enabling direct imaging of binary stars has the potential to increase the scientific yield for coronagraphic instruments planned on NASA's future space missions and concepts, including the Roman Space Telescope and the Astro2020 IR/O/UV flagship. Multi-Star Wavefront Control (MSWC) is a wavefront-control technique that simultaneously removes the (mutually incoherent) stellar leakage from both stellar components, enabling direct imaging of planets in many binary star systems. MSWC is an algorithmic technique and can be used with existing wavefront control systems on coronagraphic instruments (as well as starshades if a deformable mirror is available in the optical path) including planned observations on the upcoming PICTURE-D balloon flight. We report on the latest experimental and numerical results obtained with MSWC as part of the technology development effort to demonstrate compatibility with existing high-contrast imaging platforms for this technique. We first report on functional tests carried out at Subaru's SCExAO instrument operating in-air and showing the sub-Nyquist mode at 4.1e-6 contrast in monochromatic light. The Super-Nyquist regime of MSWC was recently tested in vacuum at JPL's High Contrast Imaging Testbed (HCIT) on the Decadal Survey Testbed (DST) reaching 8.6e-9 contrast in a 10% band. We also report on results for the current stage of vacuum testing at HCIT's Occulting Mask Coronagraph (OMC) testbed using a mask similar to the contributed MSWC mask on the Roman Space Telescope's coronagraph instrument which has demonstrated suppression at the 9.8e-9 contrast at Super-Nyquist separations around the 3rd diffraction order and is planned to use a novel binary source simulator.

  • Testing Baryonic Acoustic Oscillation Reconstruction for the Roman Survey - S. Bet (Ohio U.) et al.
    (Monday, January 9, 3:20–3:30 p.m. PST)
    The Nancy Grace Roman Space Telescope is scheduled to launch in Summer 2027, and one of its key science goals will be probing the expansion history of the Universe. We use the Roman High Latitude Spectroscopic Survey (HLSS) Galaxy Mock Catalog, which assumes H-alpha galaxies that span 2000 square degrees over 1
  • Transiting Exoplanets in the Roman Galactic Bulge Survey - R.F. Wilson (NASA GSFC) et al.
    (Tuesday, January 10, 2:10–2:20 p.m. PST)
    Among the Core Community Surveys planned for the Nancy Grace Roman Space Telescope (Roman) is a two square degrees survey of the Galactic Bulge at an approximately 15-minute cadence, resulting in tens of millions of stars with time series photometry. This dataset will enable the detection of an unprecedented number of transiting exoplanets and lead to several breakthroughs in our knowledge of exoplanet demographics. To understand the population of exoplanets we will find, we created software to efficiently simulate observations of the Galactic Bulge from the Roman Wide Field Imager and applied this software to inject transits into synthetic images, extract light curves, and perform transit detection. Combining these simulations with Galactic models and exoplanet occurrence rates gives an estimate for the number of transiting exoplanets that Roman will find. We present these predictions and discuss reasons why the actual yields may differ due to areas of parameter space that are not yet well understood, such as giant planets orbiting low-mass stars, or due to differences between the stellar populations in the Galactic Bulge and Solar neighborhood.

  • Unveiling a Population of Young, Nearby Exosatellites with Roman - M. Soares-Furtado (U. Wisconsin-Madison) et al.
    (Wednesday, January 11, 11:20–11:30 a.m. PST)
    I present the design considerations and scientific outcomes expected to accompany the proposed Transiting Exosatellites, Moons, and Planets in Orion (TEMPO) Survey. TEMPO would consist of a 30-day, time-domain photometric investigation of the nearby (400 pc) Orion Nebula Cluster (1-3 Myr) and surrounding regions using the Nancy Grace Roman Space Telescope. At these young ages, free floating planets and brown dwarfs shine bright in infrared wavelengths (1-2 microns) and can be monitored for transiting exosatellites. A TEMPO-like survey would offer a unique opportunity to provide the first census demographics of exosatellites in orbit about free floating planets and brown dwarfs. Such a population would provide invaluable constraints to theories of exosatellite formation and evolution, H/He envelope loss/capture, and the dynamical evolution of these young systems. In this talk, I describe the model-derived detection yields that would accompany the TEMPO survey and review the open questions that these data could help to constrain.

  • 3d scene reconstruction of Roman slitless spectra for host-galaxy subtraction - T. Astraatmadja (STScI) et al.
    (Wednesday, January 11, 2:30–2:40 p.m. PST)
    One of Nancy Grace Roman Space Telescope's primary goals is to improve our understanding of the nature of dark energy by measuring the geometry of the universe using Supernova Type Ia (SN Ia) survey as standardizable candles. Proposed SN Ia surveys will be carried out using Roman's Wide Field Instrument (WFI), consisting of seven filters covering 7500--20000 Angstrom as well as slitless prism and grism for spectroscopy. An inherent problem associated with using a slitless prism for wide-field spectroscopic surveys is the blending of spectra of close objects. In particular, SNe Ia spectra will be contaminated by their host galaxies. Accurately removing the host galaxy spectrum to obtain a clean, SN-only spectrum improves the accuracy of SNe luminosity distances and intrinsic brightness thus providing a more accurate determination of the dark energy parameters. We solve the challenge of cleanly subtracting a host galaxy spectrum by reconstructing the scene of a host-galaxy from spectra observed at various rotation angles during the course of the survey from either before or significantly after the SN. The reconstructed scene can then be used to predict what the spectrum of that particular galaxy would look like at a new, unseen rotation angle that was not in the original data set used for reconstruction. In this presentation we show results from our analysis of the resulting host-galaxy-subtracted spectra of SNe Ia at various redshifts and evaluate how well we can recover the SNe Ia spectra given the statistical and systematic uncertainties of different survey observing strategies.

  • WFC3 IR Faint spectrophotometric white dwarf standards for Cross-calibration of HST, Euclid and Roman - S. Deustua (NIST) et al.
    (Thursday, January 12, 2:40–2:50 p.m. PST)
    One of the most exciting results in modern cosmology was the discovery of the accelerated expansion of the Universe, possibly due to an unknown energy component (i.e., dark energy) or the modification of general relativity. In order to illuminate the unknown nature of the observed cosmic acceleration, ESA's Euclid and NASA's Roman Space Telescopes will complement each other in probing cosmic acceleration with high precision and accuracy, but need to meet unprecedented accuracy requirements on spectrophotometry. Accurate absolute spectrophotometry is vital to determine the fraction of baryonic matter turned into stars, for galaxy and supernovae surveys, and to enable legacy science. Extreme care must be taken to control systematic errors and biases. We present high signal to noise WFC3-IR spectroscopy of six faint, V~15.5 - 18 mag, hot White Dwarfs that are in or near the continuous viewing zones of both telescopes. This allows for year-round accessibility. Standard stars that are readily accessible anywhere in the sky, and that are as faint as the science targets help mitigate against non-linearity effects that have large contributions to uncertainty budgets for cosmology with type Ia supernovae. These stars are important for tying Euclid/Roman deep field spectra of e. faint galaxies to the CALSPEC calibration scale,and complement other efforts to establish faint White Dwarf standard stars for cosmology.

  • Finding extragalactic self-obscured massive evolved stars for the era of Webb and Roman - A. Thob (U. Penn.)
    (Thursday, January 12, 2:50–3:00 p.m. PST)
    Although rare, massive hypergiant evolved stars (over 30 times the mass of our Sun) strongly influence the evolution of galaxies, stars and planets through strong stellar winds and extreme late-stage evolutionary processes. Some of these stars undergo episodes of rapid mass ejections similar to the so-called "Great Eruption" of η Carinae A, one of the most well-studied hypergiants among only two stars in the Milky Way known to show this sort of behavior. Unfortunately efforts to provide clear prescriptions for such rapid stellar mass ejection events in theoretical models has been severely hampered due to the small sample of observed objects of this type. Because of their scarcity, finding new objects requires searching other galaxies besides our own for which the recently successfully launched James Webb Space Telescope will be an excellent tool for discovering them. Because these ejecta lead to dust condensing and obscuring the star, affecting its photometry in a unique way, recent work proposed a novel photometry fitting search method to identify candidates with characteristic photometric properties. This method requires computationally expensive modelling, which has until now prevented robust systematic searches across a large catalog of point source photometry. We have optimized this method for parallel processing, so that a full fit takes only days instead of months to complete, and applied it to a catalog of point source photometry in M31. We discuss our optimizations and latest updates, as well as their implications for the upcoming era of next-gen telescopes such as Roman and JWST, in particular their expected synergy in searching & studying deeper extragalactic self-obscured evolved stars. Support for this work was provided through NASA grant 80NSSC17K0349.

iPoster-Plus Sessions

  • Astrometry with STIPS: The Roman Image Simulator - S. Gomez (STScI) et al.
    (Monday, January 9, 9:00–10:00 a.m. PST)
    The Space Telescope Imaging Product Simulator (STIPS) is a Python-based pipeline maintained by The Space Telescope Science Institute (STScI) Science Operations Center (SOC). STIPS is designed to simulate full-detector scenes for the Wide-Field Instrument onboard the upcoming Nancy Grace Roman Space Telescope (Roman), planned for launch in 2027. STIPS can be used to simulate WFI scenes in units of electrons per second. Here, we present the release of STIPS 2.0, which provides much higher accuracy in terms of astrometry and flux calibration than STIPS 1.0. We show that STIPS can recover point sources with an accuracy higher than 10^-4 arcsec (or ~10^-3 pixels). Additionally, we show how different methods with varying levels of complexity compare for performing high-precision astrometry. Finally, we compare the accuracy of STIPS using Pandeia as a baseline, which is a high-fidelity Roman exposure time calculator and simulator.

  • Constraining Metallicity and Gravity of Young Exoplanets with the Nancy Grace Roman Space Telescope’s Coronagraph Instrument - A. Aleman (UCSC) et al.
    (Monday, January 9, 5:30–6:30 p.m. PST)
    The Nancy Grace Roman Space Telescope, set to launch in the mid-2020s, is a wide-field infrared survey telescope. It is designed to carry two instruments: the Wide Field Instrument and a Coronagraph Instrument. This work focuses on the Coronagraph Instrument (CGI) , a technology demonstrator intended to perform high-contrast imaging and spectroscopy of exoplanets as close as 0.15” from their host stars. One potential science focus is obtaining the first visible-light spectra of young self-luminous planets such as Beta Pictoris b. In previous work (Aleman et al. 2022), we addressed the problem of constraining exoplanet temperature and gravity measurements with spectroscopy from a simulation of the Gemini Planet Imager. Modeling the Roman spectrograph is complicated, however, by the non-linear dispersion profile of the spectroscopic prisms and the broad line spread function (Groff et al. 2021). Building on the existing framework, with models of potential young, self-luminous targets (suggested in Lacy et al. 2019), we explore the feasibility of constraining gravity and metallicity using Roman-CGI optical spectroscopy. Preliminary results suggest that a potassium line at 0.77μm remains detectable at spectral resolution of R~50 following convolution with a 4.5 pixel FWHM line-spread-function. While potassium provides more direct information about metallicity than species such as methane, constraining parameters will likely require a high signal-to-noise ratio. Nonetheless, the ability to constrain gravity and metallicity of these young planets could be an important exoplanet science result for CGI.

  • The Roman Space Telescope Science Operations Center: Overview and Progress - R. Beaton (STScI) et al.
    (Tuesday, January 10, 9:00–10:00 a.m. PST)
    The Space Telescope Science Institute (STScI) will house the Science Operations Center for NASA’s Nancy Grace Roman Space Telescope (NGRST). With launch readiness scheduled for October 2026, Roman will provide HST-like spatial resolution over 200-times larger field of view in filters spanning from 0.48 to 2.3 microns. While a Roman has a smaller aperture than JWST, Roman’s Wide Field Imager (WFI) has a simultaneous field of view of 0.271 sq. deg, having the largest etendue of any current or planned optical/infrared space observatory. As a result, Roman will have a data rate 500-times larger than HST and 23-times larger than JWST. Moreover, all data products, from raw reads to catalogs, will be staged for the community, including science-ready image-level and catalog-level data products. The Science Operations Center at STScI is responsible for building the planning, scheduling, and data processing system for WFI while providing additional data products for the WFI Imaging mode. Here we provide an overview of the SOC and provide further details for newly launched or updated activities, including data management, STIPS 2.0, RDox, the SOC Newsletter, the SOC Helpdesk, and the Roman2023 community science conference.

  • Forecasting Extragalactic Transient Light Curves From the Roman High Latitude Time Domain Core Community Survey - B. Rose (Duke) et al.
    (Tuesday, January 10, 9:00–10:00 a.m. PST)
    The High Latitude Time Domain Core Community survey will be the main data source for energetic transients from NASA's Nancy Grace Roman Space Telescope. Though this survey needs to be capable of precise dark energy measurements, there is a wide range of time domain and multi-messenger astrophysics research that will be done with this data set. Optimization of the survey for these science cases will be vital for future time allocation committees. In this talk, I will present an initial forecast (using the current reference survey) of light curve characteristics for eight classes of extragalactic transients: Kilonovae, TDEs, SLSNe, pair-instability SNe, Calcium-rich transients, SNe I-bc, SNe II, and various SNe Ia subtype.
  • Predicting the Yields of z > 6.5 Quasar Surveys in the Era of Roman and Rubin - W. Tee (U. Arizona)
    (Wednesday, January 11, 9:00–10:00 a.m. PST)
    Around 70 z > 6.5 luminous quasars have been discovered, however they are biased toward the bright end, thus do not provide a comprehensive view on quasar abundance beyond cosmic dawn. We present the predicted results of Roman/Rubin high redshift quasar survey, yielding 3 times more, 2 − 4 magnitudes deeper quasar samples, probing high redshift quasars across broad range of luminosities, especially faint quasars at Lbol ∼ 1010 L⊙ or M1450 ∼ −22 that are currently poorly explored. We include high-redshift quasars, galactic dwarfs and low-z compact galaxies with similar colors as quasar candidates in our study. We use photometry, luminosity functions and surface densities to construct population models and mock catalogs to evaluate selection completeness and efficiency. We utilize classical color dropout method in z and Y bands to select primary quasar candidates, followed up with Bayesian selection method to identify quasars. We show that the overall selection completeness > 80% and efficiency ∼ 10% at 6.5 < z < 9, with 180 quasars at z > 6.5, 20 at z > 7.5 and 2 at z > 8.5. Majority quasar contaminants are faint L and T dwarfs, rejection through proper motion is insignificant. Our results show that Roman/Rubin are able to discover a statistical sample of the earliest quasars in the Universe. The new valuable datasets worth follow up studies with James Webb Space Telescope and Extremely Large Telescopes, to determine QLF faint end slope, IGM evolution during the epoch of reionization and SMBHs growth in the early Universe.

  • The Roman Microlensing Survey in a Galactic Context with SynthPop - M. Huston (Penn State) et al.
    (Wednesday, January 11, 5:30–6:30 p.m. PST)
    The microlensing method for exoplanet detection is unique in its sensitivity to planets around stars at very large distances from the Sun, as well as low mass, cold planets. The Roman microlensing survey is estimated to detect ~1,400 new exoplanets, greatly increasing our understanding of planetary demographics in a Galactic context. In this work, we explore estimated microlensing event rates for the Roman Galactic Bulge Time Domain Survey using the SynthPop Galactic modeling software. We examine Roman’s predicted events as a function of Galactocentric distance and Galactic component membership (i.e. bulge versus disk). We also compare distributions with projections for Roman's transiting planet detections.

  • Previewing Roman’s Survey of Stellar Halos with the FOGGIE Simulations - A. Wright (JHU) et al.
    (Thursday, January 12, 9:00–10:00 a.m. PST)
    Over the next decade, the astronomical community will be deploying a number of instruments that will revolutionize our understanding of the low surface brightness universe. The Nancy Grace Roman Space Telescope, in particular, will combine extreme sensitivity with a wide field-of-view to become a powerful tool for studying the faint halos of stars that have been found to extend far beyond the disks of many galaxies in our cosmic neighborhood. I will show new results from the FOGGIE (Figuring Out Gas & Galaxies In Enzo) cosmological simulations aimed at making predictions for Roman’s survey of the stellar halos of nearby galaxies. The FOGGIE suite consists of zoom-in simulations of six Milky Way analogs in which resolution has been enhanced in the gas surrounding the central halo (the circumgalactic medium) and in the old stellar populations that typically make up stellar halos. This enables the simulations to better capture the quenching of dwarf galaxies as they are accreted, as well as the stellar substructure that their tidal destruction produces. I use the high-resolution FOGGIE simulations to “observe” the stellar halos of Milky Way-like galaxies at the same sensitivity and resolution as Roman will. I will discuss the origins of these stellar halos and make predictions regarding Roman's prospects for disentangling the properties of the individual dwarf galaxies that created them.

NASA Hyperwall Talks (NASA exhibit)

  • Building the Nancy Grace Roman Space Telescope - Dominic Benford (NASA GSFC)
    (Sunday, January 8, 7:05–7:20 p.m. PST)
    The Nancy Grace Roman Space Telescope is well underway. The telescope itself is complete; the instrument hardware is done; the spacecraft is well underway – and this snapshot will show you what everything looks like!

  • Paving the way for Big Eyes with Theory and Simulations - Aaron Yung (NASA GSFC)
    (Monday, January 9, 9:05–9:20 a.m. PST)
    Theoretical simulations that guide the design of Webb and Roman surveys for galaxies in the early Universe. I will present simulated JWST images and the making-of for these physically accurate predictions.

  • Completing the Galactic Census of Exoplanets with Roman - Scott Gaudi (OSU)
    (Monday, January 9, 5:30–5:45 p.m. PST)
    Summary of the Roman Galactic Bulge Time Domain Survey and how it uses the microlensing technique to compete the census of exoplanets started by Kepler.

  • Emulating Roman's grism instrument - Austen Gabrielpillai (NASA)
    (Monday, January 9, 5:45–6:00 p.m. PST)

  • Nancy Grace Roman Space Telescope Coronagraph Instrument - Alexandra Greenbaum (Caltech/IPAC)
    (Tuesday, January 10, 9:20–9:35 a.m. PST)
    Overview of the Roman Coronagraph Instrument Technology Demonstration Goals and Opportunities

  • Future Science with NASA's Nancy Grace Roman Space Telescope - Karoline Gilbert (STScI)
    (Tuesday, January 10, 2:15-2:30 p.m. PST)
    Giving a brief overview of Roman science followed by a high level overview of the community definition process.

  • The Dynamic Sky with NASA's Roman Space Telescope - Ori Fox (STScI)
    (Tuesday, January 10, 2:30-2:45 p.m. PST)
    Overview of Roman's capabilities and science goals specific to time domain science, with a focus on non-cosmological transient sky and the high-redshift Universe.

  • Roman Space Telescope's Wide Field Instrument - Ami Choi (NASA GSFC)
    (Thursday, January 12, 9:05-9:20 a.m. PST)
    Giving an update about the building of the Wide Field Instrument on the Roman Space Telescope.