0.4 keV on its equivalent width.

The lightcurve from the readout streak events shows a clear decline during the Chandra observation, by a factor of $\sim$40%. Power spectra from the readout streak events show a clear periodicity at 1000.0 seconds and its harmonics, identical to one of the spacecraft dither frequencies and thus a likely artifact (it is not seen in RXTE data). No other periodicities (such as the 57 minute orbital period, Altamirano et al. 2009a) were identified, suggesting that the transient is not seen at high inclination.

![ \[fig:spectrum\] Spectra of NGC 6440 X-2 during the July/August outburst as observed by /ACIS-S (black online), /PCA (triangles; red online), and /XRT (filled circles; green online). Top: data and absorbed power-law models. Bottom: residuals to fits. See Table 1 for details of spectral fits. ](f2.eps)

RXTE
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The [*Rossi X-ray Timing Explorer*]{} () has conducted regular scans of the Galactic bulge region since 2000 (generally covering NGC 6440 twice/week), in part to search for faint transient sources below the sensitivity of ’s all-sky monitor [@Swank01], with results promptly made available[^3]. The PCA scans are significantly more sensitive in the Galactic Bulge than the   All-Sky Monitor data. (Although dwell-by-dwell All-Sky Monitor 