# The Streams of the Gaping Abyss: A population of entangled stellar streams surrounding the Inner Galaxy

## TL;DR

This paper reports the discovery of numerous stellar streams around the inner Galaxy using Gaia data and a new detection algorithm, revealing their properties and origins, primarily as debris from globular clusters.

## Contribution

It introduces the STREAMFINDER algorithm for detecting stellar streams and presents eight new high-significance streams with detailed properties and spectroscopic confirmation.

## Key findings

- Discovered eight new stellar streams in Gaia DR2 data.
- Streams are mostly metal-poor and likely originate from globular clusters.
- The STREAMFINDER algorithm effectively identifies streams with low false positive rates.

## Abstract

We present the discovery of a large population of stellar streams that surround the inner Galaxy, found in the Gaia DR2 catalog using the new STREAMFINDER algorithm. Here we focus on the properties of eight new high-significance structures found at Heliocentric distances between 1 and 10 kpc and at Galactic latitudes $|b|>20\deg$, named Slidr, Sylgr, Ylgr, Fimbulthul, Sv\"ol, Fj\"orm, Gj\"oll and Leiptr. Spectroscopic measurements of seven of the streams confirm the detections, which are based on Gaia astrometry and photometry alone, and show that these streams are predominantly metal-poor. The sample possesses diverse orbital properties, although most of the streams appear to be debris of inner-halo globular clusters. Many more candidate streams are visible in our maps, but require follow-up spectroscopy to confirm their nature. We also explain in detail the workings of the algorithm, and gauge the incidence of false detections by running the algorithm on a smooth model of the Gaia catalog.