# ICRC 2021

Jul 12 – 23, 2021
Online
Europe/Berlin timezone

## Hotspot Update, and a new Excess of Events on the Sky Seen by the Telescope Array Experiment

Jul 15, 2021, 12:00 PM
1h 30m
03

#### 03

Talk CRI | Cosmic Ray Indirect

### Speaker

Jihyun Kim (University of Utah)

### Description

The Telescope Array (TA) experiment, the largest studying ultrahigh energy cosmic rays in the northern hemisphere, has reported an excess in the arrival direction distribution for events with energies above $5.7\times10^{19}$ eV, called the hotspot. We report here the latest results of the TA hotspot using the most recent data measured by the TA surface detector array, which is more than doubled exposure since the first publication; the hotspot still exists with 3 sigma post-trial significance. By using an oversampling search with a $20^\circ$-circle, similar to the study of the hotspot, we find that an additional excess of events at slightly lower energies. The Perseus-Pisces supercluster lies at the location of the new excess. Assuming this structure is responsible for the excess, we conducted a statistical analysis to verify the correlation between observed events and the members of the Perseus-Pisces supercluster. The analysis results will be presented at the conference.

Collaboration Telescope Array Experimental Results

### Primary authors

Jihyun Kim (University of Utah) Dmitri Ivanov (University of Utah) Prof. Hiroyuki Sagawa (ICRR) Prof. Gordon Thomson (University of Utah)