Recent Monitoring of Markarian 817
ATel #16376; R. A. Knoops, J. M. Miller (University of Michigan)
on 12 Dec 2023; 17:40 UT
Credential Certification: Jon Miller (jonmm@umich.edu)
Subjects: X-ray, AGN, Black Hole
Mrk 817 is a Seyfert 1.2 AGN at a redshift of 0.03145 (Strauss & Huchra 1988, Morales et al. 2019). Prior monitoring with the Neil Gehrels Swift Observatory revealed an unusual lack of connection between the UV and X-Ray emission that is often seen in Seyfert galaxies (Morales et al. 2019). Deep observations strongly suggest that such episodes of disconnection are due to a disk wind obstructing communication between the X-ray and UV emitting regions (Miller et al. 2021, Kara et al. 2021). In 2022, Mrk 817 entered a persistent and extremely faint X-ray state, indicating unusually strong obscuration of the central engine (Zak et al. 2024, ATEL #15316 #15323). In order to understand if Mrk 817 has recovered from this obscured state, we analyzed Swift XRT observation 00096992036, which obtained 1.75 ks of exposure starting on 2023-11-26 at 09:55:02 (UTC). The net count rate observed was 0.57 +/- 0.02 c/s. Fitting the spectrum with a simple power-law over the 0.3-10.0 keV band after binning, we measure a flux of F = 1.78 +/- 0.04 E-11 erg/cm2/s, which implies an X-ray luminosity of L = 4.07 +/- 0.08 E+43 erg/s. The combination of the count rate and flux signal that Mrk 817 was observed in a state with low obscuration, marking at least a momentary transition back into a typical state. Continued monitoring of Mrk 817 in all wavelengths is encouraged.
References:
Kara, E., et al., 2021, 922, 151
Miller, J. M., et al., 2021, ApJ, 911, L12
Miller, J. M., et al., 2022, ATEL 15323
Morales, A., et al., 2019, ApJ, 870, 54
Strauss, M. & Huchra, J., 1988, AJ, 95, 1602
Zak, M. K., et al., 2022, ATEL 15316
Zak, M. K., et al., 2024, ApJ, in press, arxiv:2312:06487
