Date
Speaker
Affiliation
Title (click for abstract)
June 5
Jodie Kiyokawa
University of Wisconsin
June 19
June 26
July 3
Independence Day (observed)
(No talk this week)
July 17
July 31
August 14
August 21
Statehood Day
(No talk this week)
Recalibrating SMBH Scaling Relations with UV-Optical SEDs of Reverberation-Mapped AGN
Jodie Kiyokawa
Graduate Student
University of Wisconsin
Wisconsin webpage
Understanding how galaxies form and evolve over cosmic time requires accurate measurements of the supermassive black holes (SMBHs) at their centers. In nearby active galactic nuclei (AGN), reverberation mapping (RM) of the broad line region (BLR) has been used to estimate SMBH masses. In addition, RM studies have established an empirical radius–luminosity (R−L) relation linking optical luminosity to BLR size, which is now widely used to estimate SMBH masses in more distant AGN where direct RM is not feasible. However, mounting evidence suggests that this standard R−L relation does not hold uniformly across all AGN. These deviations likely arise from differences in accretion properties, which affect the connection between the ultraviolet (UV) ionizing continuum and the optical continuum typically used in the R−L relation. To explore this, we use quasi-simultaneous multi-band imaging from the Las Cumbres Observatory Global Telescope network and the Hubble Space Telescope to construct UV–optical spectral energy distributions (SEDs) for a sample of 26 AGN at z ∼ 0.1–1.1 with existing RM measurements. Here, I will present preliminary results indicating a tentative correlation between the UV–optical SED slope and deviations from the R–L relation, with potential implications for correcting the R–L relation and improving SMBH mass measurements.
The EVE Mission: A NASA Small Explorer Concept
Ann Marie Cody & Laura Venuti
SETI Institute
Over the past decade, the Kepler and TESS missions have been a boon for time domain discoveries, from exoplanets to transients, pulsators and more. While the photometric precision and time sampling have proven exquisite, one shortcoming was the lack of multi-band data. We now have a chance to expand the state-of-the-art in space-based time domain monitoring by considering the sky at multiple wavelengths. This Tuesday, NASA released a call for Small Explorer (SMEX) mission proposals, including new space telescopes that could launch on a roughly five-year timescale. Our team led by PI Meredith MacGregor (JHU) has developed a novel SMEX concept focused on the time domain behaviors of thousands of young stars in the near-ultraviolet (200-300nm), optical (500-900nm), and near-infrared (1100-2000nm). With an aim to survey several dozen stellar populations in the 1-100 Myr age range, the Early Evolution Explorer (EVE) would simultaneously monitor fields in these three bands for at least 30 days at a time. In this talk we will outline EVE’s three core science objectives, which focus on the properties of young exoplanets, energetic flares, and interactions between the youngest stars and their protoplanetary disks. If selected, this mission would fill a crucial gap in our knowledge of the origins and early evolution of planetary systems.