Response to a comment on Dessert et al. "The dark matter interpretation of the 3.5 keV line is inconsistent with blank-sky observations"

TL;DR

This paper defends previous findings that the 3.5 keV line is unlikely due to dark matter decay, countering claims that background modeling could alter this conclusion, and emphasizes the robustness of their limits.

Contribution

The authors clarify that their conservative limits already account for background lines and reaffirm that the dark matter interpretation remains strongly disfavored.

Findings

Conservative limits disfavor dark matter origin of the 3.5 keV line.

Including additional background lines does not significantly change the limits.

The original conclusion remains robust despite alternative modeling claims.

Abstract

The dark matter explanation of the 3.5 keV line is strongly disfavored by our work in Dessert et al. 2020. Boyarsky et al. 2020 questions that conclusion: modeling additional background lines is claimed to weaken the limit sufficiently to re-allow a dark matter interpretation. We respond as follows. 1) A more conservative limit is obtained by modeling additional lines; this point appeared in its entirety in our work in Dessert et al., though we also showed that the inclusion of such lines is not necessary. 2) Despite suggestions in Boyarsky et al., even the more conservative limits strongly disfavor a decaying dark matter origin of the 3.5 keV line.