IfA Astrocoffee: Fall 2026
Current Research at the Institute for Astronomy
Astrocoffee talks are 20–25 minutes and informal, and all are welcome to attend and present.
Talks are held at 10:30am HST on Fridays in the IfA Mānoa Library (C-108) unless otherwise noted.
For additional information or to volunteer for an Astrocoffee talk, please contact Willem Hoogendam.
Date
Speaker
Affiliation
Title (click for abstract)
August 28
September 4
Andrea Weibel
IfA
September 11
September 18
Manon Le Teuff
ESPCI Paris
October 2
October 9
October 23
November 27
Non-instructional day
(No talk this week)
December 4
December 11
December 18
Black Hole Stars Across the Universe: A Photometric Census of the Hearts of LRDs
Andrea Weibel
Postdoctoral Research Fellow (LRD)
University of Hawaiʻi Institute for Astronomy
One of the most surprising and debated discoveries of JWST are the so-called Little Red Dots (LRDs). Photometric selections of LRDs largely rely on identifying their characteristic “V-shaped” SED. Recent work suggests this V-shape stems from a combination of a central engine – also referred to as a Black Hole Star (BH*) – and a star-forming host galaxy. We developed a new, complementary way of finding these sources by fitting BH* templates directly to the photometry. Applying this method to roughly 1,000 arcmin² of JWST imaging, we identified 241 candidates whose best-fitting SEDs are dominated by a BH* template. Importantly, our selection does not require a blue UV component. This means it can pick up objects resembling the paradigmatic sources “MoM-BH*-1” and “The Cliff,” which previous photometric searches have missed. We find that BH*-dominated sources exist across a wide range of redshifts (z ~ 1.7 – 9.3) and optical luminosities (log(L_5100A) ~ 42-44.5 erg/s). Their number density peaks around z ~ 5 – 6 and falls by about an order of magnitude down to z ~ 2. Crucially, however, BH*-dominated sources are not merely an early-Universe phenomenon but rather persist at least until cosmic noon.
Photonic lantern at the Subaru Telescope: wavefront sensing and high-contrast imaging development
Manon Le Teuff
Visiting Student
ESPCI Paris
The SCExAO photonic lantern splits incoming light into 19 modes, sensitive to specific wavefront errors, including the low-wind effect (LWE), which the pyramid WFS struggles to measure reliably. Using data from the SCExAO instrument, on-sky and with the bench, we compare photonic lantern and pyramid WFS reference frames against a Strehl-like PSF quality metric, computing how closely each sensor’s frame-to-frame distances track changes over time. Preliminary results show the photonic lantern gives a more consistent estimate for certain modes and performs comparably for higher orders, supporting its use as a complementary sensor to the pyramid WFS.
Tribulations and thrills of the 2026 total solar eclipse expedition
Shadia Habbal
Astronomer
University of Hawaiʻi Institute for Astronomy
The path of the 12 August 2026 total solar eclipse passed over Iceland and Spain. This presentation will highlight some of the difficulties and the highlights of this expedition. Beautiful eclipse photos, fun pictures, and videos will be shared with the audience.
TBA
Mark Neyrinck
Cosmology Researcher
University of Hawaiʻi Institute for Astronomy
Coming soon.
TBA
Rodrigo Ferrer-Chavez
Graduate Student
Northwestern
Coming soon.
Institute for Astronomy
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