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2. We revisited the disk and disk-halo interface (innermost CGM) of NGC3221 with the deep data (PI: Das). This led to a series of interesting findings: 1) Compton-thick, low-luminosity AGN; 2) ULXs with different and variable hardness ratios than assumed before, questioning our usual empirical methods to construct the X-ray luminosity function; 3) a hotter (~0.6 keV) phase both in the ISM and innermost CGM, in addition to the fiducial hot (~0.2 keV) phase; and 4) a less dense but hotter CGM than the ISM, contradicting the assumption often made in imaging-only analysis. There lies the irreplaceable power of combined spatial-temporal-spectral analysis, enabled by deep data (Das et al. 2026, ApJ, 997)
1. The evidence for a non-isothermal, extended (>150 kpc), massive (~1e11 Msun), warm-hot (~1e6 K) CGM around an L* star-forming galaxy, NGC 3221, which might account for its missing galactic baryons: a joint discovery using Suzaku and XMM-Newton data (Das et al. 2019, ApJ, 885; Das et al. 2020, ApJ, 897). This is the only L* galaxy with a detected warm-hot CGM. [We have been awarded 450 ks of XMM-Newton time to observe it in further detail.]
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