  We present the multi-wavelength observations of a flux rope that was trying
to erupt from NOAA AR 11045 and the associated M-class solar flare on 12
February 2010 using space and ground based observations from TRACE, STEREO,
SOHO/MDI, Hinode/XRT and BBSO. While the flux rope was rising from the active
region, an M1.1/2F class flare was triggered nearby one of its footpoints. We
suggest that the flare triggering was due to the reconnection of a rising flux
rope with the surrounding low-lying magnetic loops. The flux rope reached a
projected height of ~0.15 Rs with a speed of ~90 km/s while the soft X-ray flux
enhanced gradually during its rise. The flux rope was suppressed by an
overlying field and the filled plasma moved towards the negative polarity field
to the west of its activation site. We find the first observational evidence of
the initial suppression of a flux rope due to a remnant filament visible both
at chromospheric and coronal temperatures that evolved couple of days before at
the same location in the active region. SOHO/MDI magnetograms show the
emergence of a bipole ~12 h prior to the flare initiation. The emerged negative
polarity moved towards the flux rope activation site, and flare triggering near
the photospheric polarity inversion line (PIL) took place. The motion of the
negative polarity region towards PIL helped in the build-up of magnetic energy
at the flare and flux rope activation site. This study provides a unique
observational evidence of a rising flux rope that failed to erupt due to a
remnant filament and overlying magnetic field, as well as associated triggering
of an M-class flare.
