Joel Leja

Nov 6, 2024 | nature.com | Kritti Sharma |Stella Ocker |Myles Sherman |Gregg Hallinan |James Lamb |Joel Leja | +4 more

AbstractFast radio bursts (FRBs) are millisecond-duration events detected from beyond the Milky Way. FRB emission characteristics favour highly magnetized neutron stars, or magnetars, as the sources1, as evidenced by FRB-like bursts from a galactic magnetar2,3, and the star-forming nature of FRB host galaxies4,5. However, the processes that produce FRB sources remain unknown6.

Jun 26, 2024 | iopscience.iop.org | Bingjie Wang |Joel Leja |Anna de Graaff |Max-Planck-Institut für Astronomie

In the cores of the most massive galaxies in the local Universe, stars have inferred stellar age of ∼13 Gyr and high α-element abundance, suggesting that their stellar components are formed at z ≳ 5 in a spectacular and short burst of star formation (e.g., Thomas et al. 2005).

Feb 14, 2024 | nature.com | Lukas J. Furtak |Ivo Labbe |Adi Zitrin |Anna de Graaff |Rachel Bezanson |Gabriel Brammer | +14 more

AbstractEarly JWST observations have uncovered a new population of red sources that might represent a previously overlooked phase of supermassive black hole growth1−−3. One of the most intriguing examples is an extremely red, point-like object that was found to be triply-imaged by the strong lensing (SL) cluster Abell 27444. Here we present deep JWST/NIRSpec observations of this object, Abell2744-QSO1.