Asymmetric Blasts: Inside the Ejecta of GRB 180728A / SN 2018fip

In this episode, we dive into the fascinating discovery of **GRB 180728A**, one of the nearest and most energetic long-duration gamma-ray bursts ever recorded at a low redshift. While most nearby bursts are low-energy events, this explosion released a massive **$2.5 \times 10^{51}$ erg of isotropic energy**, placing it in a rare class of cosmological powerhouses found right in our relative "backyard". We explore the detailed analysis of its associated supernova, **SN 2018fip**, and what it reveals about the complex nature of stellar collapses.

**Key Topics Covered:**

* **A Rare High-Energy Event:** Learn why GRB 180728A is significant, sitting at a redshift of **z = 0.1171** and ranking as one of the most energetic nearby bursts after the famous GRB 030329 and the record-breaking "BOAT" (GRB 221009A).

* **The Supernova Mystery:** Despite the high energy of the gamma-ray burst itself, the associated supernova SN 2018fip was **intrinsically fainter** than many typical events, showing that the energy of a burst doesn't always correlate with the brightness of its supernova.

* **The Shape of the Blast:** Discover why researchers believe this wasn't a simple spherical explosion. The sources suggest a **two-component ejecta** model: a narrow, high-velocity component (> 20,000 km/s) and a slower, more massive inner component.

* **The Neighborhood:** We take a look at the **host galaxy**—a low-mass, blue, star-forming irregular dwarf galaxy typical for these types of cosmic events.

* **Advanced Observations:** Insights into how astronomers used instruments like the **X-shooter** on the Very Large Telescope to track the explosion for 80 days.

**Featured Reference:**

Rossi, A., Izzo, L., Maeda, K., et al. (2026). **"GRB 180728A and SN 2018fip: the nearest high-energy cosmological gamma-ray burst with an associated supernova."** *Astronomy & Astrophysics*.

Acknowledements: Podcast prepared with Google/NotebookLM. Illustration credits: Anna Serena Esposito