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<jats:title>Abstract</jats:title> <jats:p>Combining the <jats:italic>Solar Dynamics Observatory</jats:italic> and the New Vacuum Solar Telescope observations, we study a confined flare triggered by a rising flux rope within the trailing sunspots of active region 12733. The flux rope lying above the sheared polarity inversion line can be constructed through magnetic extrapolation but could not be detected in multiwavelength images at the pre-flare stage. The conspicuous shearing motions between the opposite-polarity fields in the photosphere are considered to be responsible for the flux rope formation. The maximum twist of the flux rope is as high as −1.76, and then the flux rope rises due to the kink instability. Only when the flare starts can the flux rope be observed in high-temperature wavelengths. The differential emission measure results confirm that this flux rope is a high-temperature structure. Associated with the rising flux rope, there appear many post-flare loops and a pair of flare ribbons. When the rising flux rope meets and reconnects with the large-scale overlying field lines, a set of large-scale twisted loops are formed, and two flare ribbons propagating in opposite directions appear on the outskirts of the former ribbons, indicating that the twist of the flux rope is transferred to a much larger system. These results imply that the external reconnection between the rising flux rope and the large-scale overlying loops plays an important role in the confined flare formation.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Measurements of [Fe/H] and [<jats:italic>α</jats:italic>/Fe] can probe the minor merging history of a galaxy, providing a direct way to test the hierarchical assembly paradigm. While measurements of [<jats:italic>α</jats:italic>/Fe] have been made in the stellar halo of the Milky Way (MW), little is known about detailed chemical abundances in the stellar halo of M31. To make progress with existing telescopes, we apply spectral synthesis to low-resolution DEIMOS spectroscopy (<jats:italic>R</jats:italic> ∼ 2500 at 7000 Å) across a wide spectral range (4500 Å &lt; <jats:italic>λ</jats:italic> &lt; 9100 Å). By applying our technique to low-resolution spectra of  170  giant stars in  five MW globular clusters, we demonstrate that our technique reproduces previous measurements from higher resolution spectroscopy. Based on the intrinsic dispersion in [Fe/H] and [<jats:italic>α</jats:italic>/Fe] of individual stars in our combined cluster sample, we estimate systematic uncertainties of ∼0.11 dex and ∼0.09 dex in [Fe/H] and [<jats:italic>α</jats:italic>/Fe], respectively. We apply our method to deep, low-resolution spectra of  11  red giant branch stars in the smooth halo of M31, resulting in higher signal-to-noise ratios per spectral resolution element compared to DEIMOS medium-resolution spectroscopy, given the same exposure time and conditions. We find <jats:inline-formula> <jats:tex-math> <?CDATA $\langle $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1eacieqn1.gif" xlink:type="simple" /> </jats:inline-formula>[<jats:italic>α</jats:italic>/Fe]<jats:inline-formula> <jats:tex-math> <?CDATA $\rangle $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1eacieqn2.gif" xlink:type="simple" /> </jats:inline-formula> = 0.49 ± 0.29 dex and <jats:inline-formula> <jats:tex-math> <?CDATA $\langle $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1eacieqn3.gif" xlink:type="simple" /> </jats:inline-formula>[Fe/H]<jats:inline-formula> <jats:tex-math> <?CDATA $\rangle $?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1eacieqn4.gif" xlink:type="simple" /> </jats:inline-formula> = −1.59 ± 0.56 dex for our sample. This implies that—much like the MW—the smooth halo field of M31 is likely composed of disrupted dwarf galaxies with truncated star formation histories that were accreted early in  the halo’s formation.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The flux ratio of Fe <jats:sc>xxvi</jats:sc>–Ly<jats:italic>α</jats:italic> to Fe <jats:sc>xxv</jats:sc>–He<jats:italic>α</jats:italic> lines (<jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub>) is a sensitive indicator of the maximum temperature (<jats:italic>T</jats:italic> <jats:sub>max</jats:sub>), and therefore the mass of white dwarf stars (<jats:italic>M</jats:italic> <jats:sub>WD</jats:sub>) in cataclysmic variables (CVs). To examine and calibrate the theoretical <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub>–<jats:italic>T</jats:italic> <jats:sub>max</jats:sub>–<jats:italic>M</jats:italic> <jats:sub>WD</jats:sub> relations, reliable measurements of <jats:italic>T</jats:italic> <jats:sub>max</jats:sub> and <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub> are necessary. In this work, we conduct a thorough investigation of 3–50 keV X-ray spectra of 25 solar neighborhood magnetic and nonmagnetic CVs based on archival <jats:italic>NuSTAR</jats:italic> and <jats:italic>Suzaku</jats:italic> observations. The measured <jats:italic>T</jats:italic> <jats:sub>max</jats:sub> are compared to the <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub> and <jats:italic>M</jats:italic> <jats:sub>WD</jats:sub>. The results show that the sampled CVs closely follow the theoretical <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub>–<jats:italic>T</jats:italic> <jats:sub>max</jats:sub> relation. Moreover, all the <jats:italic>M</jats:italic> <jats:sub>WD</jats:sub> estimated from <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub> are consistent with the dynamically measured ones. We conclude that <jats:italic>I</jats:italic> <jats:sub>7.0</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>6.7</jats:sub> can be used as a good diagnostic for <jats:italic>T</jats:italic> <jats:sub>max</jats:sub> and <jats:italic>M</jats:italic> <jats:sub>WD</jats:sub> in both magnetic and nonmagnetic CVs.</jats:p>