A Near-infrared Search for Molecular Gas in the Fermi Bubbles

Abstract

Abstract We present Gemini/NIFS near-IR integral field spectroscopy of the fields-of-view around two AGNs behind the Fermi Bubbles (PDS 456 and 1H1613-097 ) to search for molecular gas in the Milky Way’s nuclear wind. These two AGN sightlines were selected by the presence of high-velocity neutral and ionized gas seen in UV absorption. We do not detect any extended emission from the H2 rovibrational S(0) and S(1) lines at 2.224 and 2.122 μm in either direction. For the H2 1-0 S(1) line, the 3σ surface brightness limits derived from spectra extracted across the full 3″ × 3″ NIFS field-of-view are 2.4 × 10−17 erg cm−2 s−1 Å−1 arcsec−2 for PDS 456 and 4.9 × 10−18 erg cm−2 s−1 Å−1 arcsec−2 for 1H1613-097. Given these non-detections, we conclude that CO emission studies and H2 UV absorption studies are more promising approaches for characterizing molecular gas in the Fermi Bubbles.