$L_X$(0.5-10 keV)$<7.4\times10^{30}$ , while for a hydrogen-atmosphere neutron star model [@Heinke06a], $L_X$(0.5-10 keV)$<1.6\times10^{31}$ and $L_{NS}$ (0.01-10 keV)$<6.0\times10^{31}$ (we use $L_{NS}$ as the total emission from the NS surface).

We obtained a 5 ks ACIS-S follow-up  Director’s Discretionary Time observation on Aug. 10, 2009, to see if NGC 6440 X-2 had returned to full quiescence, or was continuing to accrete at $L_X$(0.5-10 keV)$\sim5\times10^{32}$ , similarly to SAX J1808.4-3658 at the end of its 2008 outburst [@Campana08]. Two photons were detected at the position of NGC 6440 X-2 (see Fig. \[fig:image\]). As the background is quite low ($<0.01$ photons expected), both photons are probably from NGC 6440 X-2. We estimate (for an assumed spectrum similar to that in outburst) $L_X=6^{+9}_{-4}\times10^{31}$ , with uncertainties from @Gehrels86 at 90% confidence. This confirms that NGC 6440 X-2 returned to quiescence, although it appears brighter than the limits from the 2000 and 2003 quiescent observations (above).

Optical/Infrared Observations
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Archival NTT and HST
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The location of NGC 6440 X-2 has been previously observed by the European Southern Observatory’s New Technology Telescope (NTT) and by the [*Hubble Space Telescope*]{} () [@Piotto02]. The NTT imaging, in $R$ and $B$, was described by @Verbunt00, and the  imaging in 