<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Ignacio,<div><br></div><div>Thanks for the preprint. I guess this is the same work we had an interesting</div><div>discussion at the Napa meeting back in December. The results are intriguing,</div><div>especially the dependence of the loop lifetimes on the temperature. However,</div><div>you probably realize (better than we all) how many loops intersect in the</div><div>fore- and background of the line-of-sight where you choose a box and plot</div><div>a lightcurve to derive the lifetime. I have the impression that most lightcurves</div><div>contain emission from multiple loops, but I admit that it is very difficult to</div><div>disentangle them. It would be interesting if we could isolate individual loops</div><div>by proper geometric (cross-sectional+background) modeling in all filters to</div><div>see if your preliminary results hold up. </div><div>Keep us posted about further progress!</div><div><br></div><div>Cheers,</div><div>Markus</div><div><br></div><div><br></div><div><br><div><div>On Jan 9, 2009, at 5:54 AM, Ignacio Ugarte Urra wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hi all,<br><br>Just wanted to let you know about a paper on EIS/XRT observations of<br>coronal loops just accepted by ApJ.<br><br><a href="http://arxiv.org/abs/0901.1075">http://arxiv.org/abs/0901.1075</a><br><br>Title: "Active region transition region loop populations and their<br>relationship to the corona"<br>Authors: Ignacio Ugarte-Urra, Harry P. Warren and David H. Brooks<br><br>Abstract:<br>The relationships among coronal loop structures at different<br>temperatures is not settled. Previous studies have suggested that<br>coronal loops in the core of an active region are not seen cooling<br>through lower temperatures and therefore are steadily heated. If loops<br>were cooling, the transition region would be an ideal temperature regime<br>to look for a signature of their evolution. The Extreme-ultraviolet<br>Imaging Spectrometer (EIS) on Hinode provides monochromatic images of<br>the solar transition region and corona at an unprecedented cadence and<br>spatial resolution, making it an ideal instrument to shed light on this<br>issue. Analysis of observations of active region 10978 taken in 2007<br>December 8 -- 19 indicates that there are two dominant loop populations<br>in the active region: core multi-temperature loops that undergo a<br>continuous process of heating and cooling in the full observed<br>temperature range 0.4-2.5 MK and even higher as shown by the X-Ray<br>Telescope (XRT); and peripheral loops which evolve mostly in the<br>temperature range 0.4-1.3 MK. Loops at transition region temperatures<br>can reach heights of 150 Mm in the corona above the limb and develop<br>downflows with velocities in the range of 39-105 km/s.<br><br>Best,<br>Ignacio<br>-- <br>~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ <br> ~ Ignacio Ugarte-Urra ~<br> Naval Research Laboratory. Code 7673U. <br> 4555 Overlook Ave SW. Washington, DC 20375<br> Contractor. Spain.<br> phone: (+1) 202 404 1779<br> email: iugarte@ssd5.nrl.navy.mil<br> http: http://tcrb.nrl.navy.mil/~iuu<br>~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ <br><br>_______________________________________________<br>Loops mailing list<br>Loops@solar.physics.montana.edu<br>https://mithra.physics.montana.edu/mailman/listinfo/loops<br></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>____________________________________________</div><div>Dr. Markus J. Aschwanden</div><div>Solar & Astrophysics Laboratory</div><div>Lockheed Martin Advanced Techology Center</div><div>Org. ADBS, Bldg. 252</div><div>3251 Hanover St., Palo Alto, CA 94304, USA</div><div>Phone: 650-424-4001, FAX: 650-424-3994</div><div>URL: <a href="http://www.lmsal.com/~aschwand/">http://www.lmsal.com/~aschwand/</a></div><div>e-mail: <a href="mailto:aschwanden@lmsal.com">aschwanden@lmsal.com</a></div><div>_______________________________________</div><div>____________________________________</div><br class="Apple-interchange-newline"></span></span></span></div></span><br class="Apple-interchange-newline"> </div><br></div></body></html>