Discovery of Hot Gas in Outflow in NGC3379

TL;DR

This paper reports the discovery of the faintest hot gas outflow in an early type galaxy, NGC 3379, using deep Chandra observations, confirming theoretical predictions of outflowing hot ISM in such galaxies.

Contribution

It presents the first detection of a very low luminosity, outflowing hot interstellar medium in NGC 3379, aligning observations with theoretical models.

Findings

Hot gas luminosity ~4x10^37 erg/s detected

Hot gas is in an outflow phase

Observed properties match theoretical predictions

Abstract

We report the discovery of a faint (L_x ~ 4 10^37 erg/s, 0.5-2 keV), out-flowing gaseous hot interstellar medium (ISM) in NGC 3379. This represents the lowest X-ray luminosity ever measured from a hot phase of the ISM in a nearby early type galaxy. The discovery of the hot ISM in a very deep Chandra observation was possible thanks to its unique spectral and spatial signatures, which distinguish it from the integrated stellar X-ray emission, responsible for most of the unresolved emission in the Chandra data. This hot component is found in a region of about 800 pc in radius at the center of the galaxy and has a total mass M~ 3 10^5 solar masses. Independent theoretical prediction of the characteristics of an ISM in this galaxy, based on the intrinsic properti es of NGC 3379, reproduce well the observed luminosity, temperature, and radial distribution and mass of the hot gas, and indicate that the gas is in an outflowing phase, predicted by models but not observed in any system so far.