The Soft X-Ray Counterpart of Hanny's Voorwerp Near IC 2497

The Soft X-Ray Counterpart of Hanny's Voorwerp Near IC 2497Fabbiano, GiuseppinaElvis, MartinDOI: info:10.3847/1538-4357/ab4187v. 884163
Fabbiano, Giuseppina and Elvis, Martin. 2019. "The Soft X-Ray Counterpart of Hanny's Voorwerp Near IC 2497." The Astrophysical Journal 884:163. https://doi.org/10.3847/1538-4357/ab4187
ID: 154627
Type: article
Authors: Fabbiano, Giuseppina; Elvis, Martin
Abstract: We report the detection in Chandra Advanced CCD Imaging Spectrometer archival data of an elongated soft (40 erg s-1. We infer an [O III]/soft-X-ray ratio in the range of ̃200, consistent with the highest values measured in some of the clouds of NGC 4151. Overall, given the uncertainties, Hanny's Voorwerp appears to be a feature consistent with the ionization cone emission of nearby AGNs. We estimate an X-ray recombination time of ̃2 × 107 yr, longer than the [O III] recombination time (̃8000 yr). This suggests that extended soft X-ray components may be a better diagnostic of overall long-term activity, while detection of an [O III] HV would point to a time-limited activity burst.