[Loops] new paper on Hi-C observations

[Paola Testa]

Dear all,

the following paper has recently been accepted by ApJ Letters. You can 
find a copy of the paper and relevant movies at 
www.lmsal.com/~ptesta/hic_moss/

thanks,
Paola

title:
Observing coronal nanoflares in active region moss

authors:
P. Testa, B. De Pontieu, J. Martinez-Sykora, E. DeLuca, V. Hansteen, J. 
Cirtain, A. Winebarger, L. Golub, K. Kobayashi, K. Korreck, S. Kuzin, R. 
Walsh, C. DeForest, A. Title, M.Weber

abstract:
The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A 
images of the upper transition region moss at an unprecedented spatial 
(~0.3-0.4 arcsec) and temporal (5.5s) resolution.
The Hi-C observations show in some moss regions variability on 
timescales down to ~15s, significantly shorter than the minute scale 
variability typically found in previous observations of moss, therefore 
challenging the conclusion of moss being heated in a mostly steady 
manner.  These rapid variability moss regions are located at the 
footpoints of bright hot coronal loops observed by SDO/AIA in the 94A 
channel, and by Hinode/XRT.
The configuration of these loops is highly dynamic, and suggestive of 
slipping reconnection.
We interpret these events as signatures of heating events associated 
with reconnection occurring in the overlying hot coronal loops, i.e., 
coronal nanoflares.
We estimate the order of magnitude of the energy in these events to be 
of at least a few $10^{23}$~erg, also supporting the nanoflare scenario.
These Hi-C observations suggest that future observations at comparable 
high spatial and temporal resolution, with more extensive temperature 
coverage are required to determine the exact characteristics of the 
heating mechanism(s).