Roman Information Sessions

Programme and access details

Note: Access details have been sent to the list of participants. If you haven't received it, or would still like to attend the Sessions, please send an email to roman-information-sessioncosmos.esa.int .

Programme

Invited speakers

Contributing speakers

[Click on the titles to download the presentation]

Additional Contributions

• Jean Schneider: The Random Transiter HD 139139

Abstracts

Exoplanet Demographics with Roman

Scott Gaudi

The Ohio State University

Measurements of the demographics of exoplanets over a range of planet and host star properties provide fundamental empirical constraints on theories of planet formation and evolution.  I will discuss the potential for the Nancy Grace Roman Space Telescope to provide exoplanet demographics over broad regions of parameter space.   The Roman Galactic Exoplanet (RGES) survey will be uniquely sensitive to low-mass, long-period, and free-floating planets via the microlensing technique. Furthermore, the RGES survey is predicted to detect roughly 100,000 transiting planets with radii as low as 2 Earth radii, and periods less than roughly 30 days. When combined with the results from Kepler, the RGES survey will yield a nearly complete picture of the demographics of planetary systems throughout the Galaxy.

Science Support at SSC / IPAC

Lee Armus

IPAC

IPAC will partner with the Goddard Space Flight Center and the Space Telescope Science Institute to provide the Science Center functions for the Roman Space Telescope mission.  The Roman Science Support Center (SSC) at IPAC is responsible for science data processing for the Galactic Bulge Time Domain Survey, and the spectroscopic science data processing for the High Latitude Wide Area and Time Domain Surveys.  The SSC will also issue the Roman call for proposals and manage the review process, support the Coronagraph Instrument operations, and engage the exoplanet and wide-field spectroscopy astronomical communities.  During this talk, we will provide an overview of these SSC functions, and discuss how they may relate to participation by the European community.

Roman and Euclid Synergies in weak lensing

Thomas Kitching

University College London

I will discuss synergies between the ESA Euclid mission and Roman, focussing in particular on how both missions can help each other to 1) overcome systematic effects and improve overall cosmological constraints, 2) enable higher-order weak lensing measurements, and 3) probe a larger dynamic range in redshift enabling non-parametric dark energy measurements.

Synergistic cosmology across the spectrum

Stefano Camera

University of Turin

Cross-correlations between cosmological and astrophysical observables at different wavelengths have the potential to lift degeneracies and obtain results that are 'more than the sum of the parts'.  In this talk, I shall explore how Roman can synergies with other forthcoming cosmological experiments such as Euclid and the SKAO to deepen our knowledge about the most pressing unanswered questions in cosmology, such as the nature of dark matter, dark energy, and inflation.

Gravitationally lensed Supernovae

Ariel Goobar   

Stockholm University

Roman opens up exciting avenues w.r.t exotic transients and gravitationally lensed supernovae rank very highly among these. The science reach is significant in at least three different areas of cosmology and astrophysics.
First, multiply imaged supernovae will allow us to do very accurate time-delay cosmography, an excellent tool to measure the Hubble constant, and a probe for the graininess of matter in the central regions of galaxies, with implications for our understanding of dark matter. In particular, a combined search and follow-up with LSST could be highly advantageous.
Second, we can use gravitational lensing to boost the reach of man-made telescopes. For example, observations through very massive clusters of galaxies would allow us to detect and study supernova explosions at redshift ranges well beyond what is otherwise accessible, possibly probing the first generation of supernovae in the Universe.
Third, the boosting of lensing of high-redshift Type Ia supernovae would allow us to carry out detailed spectroscopic studies in a handful of cases, with similar accuracy as their low-z counterparts. This is necessary to verify the “standardizeable candle”nature of these precious distance indicators. Ultimately, the reliability of the measurements of the equation of state parameter of dark energy based on SNIa Hubble diagrams, one of the main mission goals, would depend on this.

Cosmological simulations for cosmological surveys

Francisco Castander   

ICE-CSIC, IEEC, Barcelona

Cosmological simulations are important to design and optimize cosmological surveys and to interpret and analyze the resulting data. We have been developing simulation for the current cosmological surveys like PAUS and DES. We are currently leading the effort of the cosmological simulations in Euclid. WE intend to continue our effort with the knowledge obtained from the upcoming surveys.

Euclid-Roman joint observation towards the Galactic Bulge

Etienne Bachelet

Las Cumbres Observatory

The Roman microlensing survey is expected to discover more than 1500 hundred planets and dozen of unbound planets. However, a significant fraction of this sample will need extra measurements to accurately measure the mass of these planets. In this presentation, I will present the benefits of Euclid observation of the Roman microlensing fields. First, I will present the potential of  early imaging with Euclid that provide strong constraints on the lens systems. Secondly, I will show that simultaneous observations from the two observatories can constraints the mass of a large sample of unbound planets.

EMCCDs for the Nancy Grace Roman Space Telescope: the detector design, the challenges involved and their ongoing validation

David Hall

Open University

The CEI at the Open University has been involved in the detector development for the RST since 2014, contracted by JPL for much of this time to perform detector test and validation, bespoke detector design for the coronagraph and post-production testing.  Sensors from the production runs for the coronagraph will be delivered to the Open University in late 2021 with the intention of providing vital test and validation results to the instrument team.  This talk will provide a brief outline of the work performed over the last seven years en route to the flight model production, the challenges encountered, and the requirements for their ongoing validation.        

Polarimetric characterization of exoplanets and debris disks

Frans Snik       

Leiden Observatory

The Nancy G. Roman Space Telescope Coronagraph Instrument will be the first instrument with sufficient raw contrast to directly image gas giant exoplanets in reflected light. Its polarimetric mode will provide unique characterization of debris disks that are too faint to image from the ground, but much brighter than the projected contrast floor. The polarimetric performance is limited by its implementation without temporal modulation, and by instrumental polarization and polarization aberrations. We propose to implement an advanced calibration plan and data pipeline to go well beyond the modest instrument goals to provide deep polarimetric contrast and high-accuracy polarimetric characterizations for debris disks and possibly the brightest Jupiter-like exoplanets.

The scientific potential of reflected-starlight observations and a catalogue of targets accessible to Roman

Oscar Carrión-González

Technische Universität Berlin

The coronagraph instrument (CGI) aboard Roman will perform the first direct-imaging observations of exoplanets in reflected starlight. This technique will provide insights into a population of cold and temperate exoplanets whose atmospheres cannot be characterized with current facilities. In this talk we analyse the science outcome of the CGI during a possible phase of science operations. First, we computed a catalogue of known exoplanets that are potentially observable in reflected starlight with the CGI. Given that the final coronagraph specifications are not available yet, we applied our methodology to several plausible scenarios based on current estimates of the instrument performance. We show how the prospects for detectability change if RV and astrometry observations reduce the uncertainties in the orbital parameters, particularly the inclination. Second, we analyse the potential of reflected-starlight observations to characterize the atmospheres of cold exoplanets. For that we developed an MCMC retrieval method and applied it to simulated measurements. We found that, if the planet radius is unknown, a single observation generally fails to characterize the atmospheric properties. In this case, the abundance of gaseous species is not accurately constrained and it becomes challenging to distinguish between cloudy and cloud-free atmospheres. This holds true regardless of the star-planet-observer phase angle of the observation. We also find that combining observations at multiple phase angles is an effective strategy to improve the accuracy of the retrievals. This suggests that exoplanets with a wide range of observable phase angles are particularly suitable for atmospheric characterization. In addition to its interest as a technology demonstrator, the CGI can perform ground-breaking measurements that otherwise would not be available until the launch of LUVOIR or HabEx in the mid-2030s.

My God, it's full of Stars, Brown Dwarfs, and Exoplanets

José A. Caballero        

Centro de Astrobiología

Apart from dedicated CGI surveys for exoplanets (around a very well defined sample of stars), WFI at the Roman Space Telescope can offer unique possibilities for science cases on brown dwarfs and substellar objects below the deuterium burning mass limit (aka rogue planets), including objects at close distances and with very cool effective temperatures and at further distances but very young and, therefore, overluminous. Even with only 'extragalactic' pointings, WFI data would provide a wealth of results for refining the (initial) mass function determination. In this presentation, I show my ideas for maximising the scientific return for substellar and exoplanet astrophysics with no interference with the already defined main science cases. For example: which criteria should be applied to observe a certain star with CGI and why? How to disentangle high-redshift galaxies and very red ultracool dwarfs in WFI data? Should fields with open clusters and young associations be investigated?

Stellar populations of stellar streams in the local Universe

David Martínez-Delgado        

Institute of Astrofisica de Andalucia (CSIC)

We plan to undertake a comprehensive study of known stellar tidal streams around nearby Milky Way-like galaxies  observed in the large Nancy Grace Roman Space Telescope surveys, and situated at distances where the streams are not resolved into stars (i.e., beyond 20 Mpc).  These observations will allow us to understand their stellar populations, stellar masses, and their contribution to the building-up of the stellar halos  based on the photometric analysis of their integrated (i.e., unresolved) diffuse light. Our study therefore will  complement and expand on resolved stellar population studies of these minor merger events found in the Local Group. We also intend to compare our observations to the predictions of cosmological models of galactic halo formation to infer the properties of the stream progenitors (masses,  accretion times, stellar populations).