SHORT-TIMESCALE MONITORING OF THE X-RAY, UV, AND BROAD DOUBLE-PEAK EMISSION LINE OF THE NUCLEUS OF NGC 1097

Recent studies have suggested that the short-timescale (less than or similar to 7 days) variability of the broad (similar to 10,000 km s(-1)) double-peaked H alpha profile of the LINER nucleus of NGC 1097 could be driven by a variable X-ray emission from a central radiatively inefficient accretion flow. To test this scenario, we have monitored the NGC 1097 nucleus in X-ray and UV continuum with Swift and the H alpha flux and profile in the optical spectrum using SOAR and Gemini-South from 2012 August to 2013 February. During the monitoring campaign, the H alpha flux remained at a very low level-three times lower than the maximum flux observed in previous campaigns and showing only limited (similar to 20%) variability. The X-ray variations were small, only similar to 13% throughout the campaign, while the UV did not show significant variations. We concluded that the timescale of the H alpha profile variation is close to the sampling interval of the optical observations, which results in only a marginal correlation between the X-ray and H alpha fluxes. We have caught the active galaxy nucleus in NGC 1097 in a very low activity state, in which the ionizing source was very weak and capable of ionizing just the innermost part of the gas in the disk. Nonetheless, the data presented here still support the picture in which the gas that emits the broad double-peaked Balmer lines is illuminated/ionized by a source of high-energy photons which is located interior to the inner radius of the line-emitting part of the disk.