The center of the Milky Way contains some of the most extreme conditions for star formation in the Galaxy, providing an ideal laboratory for testing theories of star formation, which often fail in this enigmatic region. Only one Galactic Center H II region, known as the Sickle, contains structures analogous to the iconic pillars. The Sickle, however, is not located at the edge of a natal H II region, but rather results from interactions between its molecular cloud, and a massive star cluster, known at the Quintuplet Cluster, which is rapidly transiting the Galactic Center.

We will present JWST MIRI and NIRCam images of the Sickle obtained in May and August 2024 respectively, which reveal in stunning detail the northern ionization front of the Sickle. Preliminary analysis shows two large pillars remarkably similar in morphology and size to the two large pillars in M16. There are also several smaller pillars of varying morphology depending on their location relative to the primary ionizing sources, and possible evidence of proplyds all along the ionization front. In addition, one feature (assumed to be another pillar candidate at lower resolution) appears to be the result of protostellar outflow, possibly a jet, which terminates in a previously unknown bow shock as it encounters the dense edge of the molecular cloud. We will address whether the observational data is consistent with triggered low-mass star formation occurring along the Sickle ionization front.">

The Sickle: Pillars of Creation in the Galactic Center (original) (raw)

Abstract

As H II regions expand into their natal molecular clouds, they often create bubbles whose rims contain bright ionization fronts sculpted into features similar to the beautiful and iconic "Pillars of Creation" in M16. Models confirm that these features are sites of current star formation, but questions remain as to whether the stars forming there have been triggered or are simply being revealed as their surrounding cloud is eroded away. Very high-resolution images from nearby regions have enabled these models to be rigorously tested, but for a limited range of environmental conditions.

The center of the Milky Way contains some of the most extreme conditions for star formation in the Galaxy, providing an ideal laboratory for testing theories of star formation, which often fail in this enigmatic region. Only one Galactic Center H II region, known as the Sickle, contains structures analogous to the iconic pillars. The Sickle, however, is not located at the edge of a natal H II region, but rather results from interactions between its molecular cloud, and a massive star cluster, known at the Quintuplet Cluster, which is rapidly transiting the Galactic Center.

We will present JWST MIRI and NIRCam images of the Sickle obtained in May and August 2024 respectively, which reveal in stunning detail the northern ionization front of the Sickle. Preliminary analysis shows two large pillars remarkably similar in morphology and size to the two large pillars in M16. There are also several smaller pillars of varying morphology depending on their location relative to the primary ionizing sources, and possible evidence of proplyds all along the ionization front. In addition, one feature (assumed to be another pillar candidate at lower resolution) appears to be the result of protostellar outflow, possibly a jet, which terminates in a previously unknown bow shock as it encounters the dense edge of the molecular cloud. We will address whether the observational data is consistent with triggered low-mass star formation occurring along the Sickle ionization front.