We measured temporal and emission properties of quiescent magnetars using archival Chandra and XMM-Newton data, produced a list of the properties for 17 magnetars, and revisited previously suggested correlations between the properties. Our studies carried out with a larger sample, better spectral characterizations, and more thorough analyses not only confirmed previously-suggested correlations but also found new ones. The observed correlations differ from those seen in other neutron-star populations but generally accord with magnetar models. Specifically, the trends of the intriguing correlations of blackbody luminosity (𝐿BB) with the spin-inferred dipole magnetic field strength (𝐵S) and characteristic age (𝜏c) were measured to be 𝐿BB ∝ 𝐵1.5 S and 𝐿BB ∝ 𝜏−0.6 c , supporting the twisted magnetosphere and magnetothermal evolution models for magnetars. We report the analysis results and discuss our findings in the context of magnetar models.

Abstract
1. Introduction
2. Target Selection and Data Reduction
3. Data Analysis Result
    3.1. Spectral Analysis
    3.2. Timing Analysis
    3.3. Results of the Spectral and Timing Analyses
4. Correlation Analysis
    4.1. Correlation Study with the Baseline Model Parameters
    4.2. Correlation Study with Alternative Spectral Models
5. Discussion
    5.1. Significant Correlations between Temporal andEmission Properties
    5.2. Correlation between 𝐵S and 𝑘𝑇
    5.3. Correlations between Emission Properties
    5.4. Comparisons with Other Neutron-Star Populations
6. Summary
Acknowledgments
References

• Jiwoo Seo(Department of Astronomy and Space Science, Chungbuk National University)
• Jaewon Lee(Department of Astronomy and Space Science, Chungbuk National University, METASPACE)
• Hongjun An(Department of Astronomy and Space Science, Chungbuk National University) Corresponding Author