Extracting the Temperature of a Coronal Loop in the Solar Active Region 11092

TL;DR

This paper presents a method to determine the temperature of solar coronal loops using intensity ratios from multi-wavelength EUV images, providing insights into the thermal structure and evolution of active region loops.

Contribution

It introduces a temperature estimation technique based on intensity ratios and response functions, applied to AIA data, offering an alternative to Gaussian DEM fitting methods.

Findings

Estimated loop temperature at 1.3 million Kelvin.

Identified hotter and superficial points with temperatures around 10 million and 1.4 million Kelvin.

Temperature ratios are highly sensitive to temporal variations.

Abstract

Extracting the temperature of coronal loops is effective in the analysis of solar active region's loops and helps in better understanding of coronal events. To this end, various methods have already been developed like the method developed by Aschwanden et al. 2015 \cite{AschwandenB2015} which is based on Gaussian fit for Differential Emission Measure (DEM). Here, we use the intensity ratios of the images in three different wavelengths and the temperature response functions of AIA to extract the temperature of the loop. In this paper, we use EUV images of the solar active region 11092 taken by AIA instrument of the SDO satellite at 171, 193, and 211 $A^{0}$ wavelengths, at 1th of August, 2010. We select a loop in a subregion of 11092 and extract its temperature by the help of intensity profiles in different wavelengths and thermal response functions of different filters. In this subregion cooling of the loop happens and in the selected loop, highest relative intensity of the wavelengths of 171 $A^{0}$ to 193 $A^{0}$ was obtained to be $0.76$ and this number was estimated to correspond to the temperature of 1.3 million degree of Kelvin, which is the maximum temperature point of this loop's internal area. The highest values of the intensity ratios at the wavelengths of 211$A^{0}$ to 193$A^{0}$, and 211$A^{0}$ to 171$A^{0}$ are $0.22$ and $0.25$, which correspond to temperature values around 10M and 1.4M Kelvin in sequence, related to the temperature of hotter and more superficial points of the loop respectively. These values are very sensitive to time and differ in time series of this event of the loop intensity variation.