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AGN STORM 2. X. The Origin of the Interband Continuum Delays in Mrk 817 * * Based in part on observations associated with program GO-16196 made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. (2024)
Journal Article
Netzer, H., Goad, M. R., Barth, A. J., Cackett, E. M., Horne, K., Hu, C., Kara, E., Korista, K. T., Kriss, G. A., Lewin, C., Montano, J., Arav, N., Behar, E., Brotherton, M. S., Chelouche, D., De Rosa, G., Dalla Bontà, E., Dehghanian, M., Ferland, G. J., Fian, C., …Zaidouni, F. (2024). AGN STORM 2. X. The Origin of the Interband Continuum Delays in Mrk 817 * * Based in part on observations associated with program GO-16196 made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. The Astrophysical Journal, 976(1), Article 59. https://doi.org/10.3847/1538-4357/ad8160

The local (z = 0.0315) active galactic nucleus (AGN) Mrk 817 was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign, AGN STORM 2. Here, we present a comprehensive analysis of the... Read More about AGN STORM 2. X. The Origin of the Interband Continuum Delays in Mrk 817 * * Based in part on observations associated with program GO-16196 made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555..

AGN STORM 2. VII. A Frequency-resolved Map of the Accretion Disk in Mrk 817: Simultaneous X-Ray Reverberation and UVOIR Disk Reprocessing Time Lags (2024)
Journal Article
Lewin, C., Kara, E., Barth, A. J., Cackett, E. M., De Rosa, G., Homayouni, Y., Horne, K., Kriss, G. A., Landt, H., Gelbord, J., Montano, J., Arav, N., Bentz, M. C., Boizelle, B. D., Dalla Bontà, E., Brotherton, M. S., Dehghanian, M., Ferland, G. J., Fian, C., Goad, M. R., …Zaidouni, F. (2024). AGN STORM 2. VII. A Frequency-resolved Map of the Accretion Disk in Mrk 817: Simultaneous X-Ray Reverberation and UVOIR Disk Reprocessing Time Lags. Astrophysical Journal, 974(2), 271. https://doi.org/10.3847/1538-4357/ad6b08

X-ray reverberation mapping is a powerful technique for probing the innermost accretion disk, whereas continuum reverberation mapping in the UV, optical, and infrared (UVOIR) reveals reprocessing by the rest of the accretion disk and broad-line regio... Read More about AGN STORM 2. VII. A Frequency-resolved Map of the Accretion Disk in Mrk 817: Simultaneous X-Ray Reverberation and UVOIR Disk Reprocessing Time Lags.

AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations* (2024)
Journal Article
Dehghanian, M., Arav, N., Kriss, G. A., Mehdipour, M., Byun, D., Walker, G., Sharma, M., Barth, A. J., Bentz, M. C., Boizelle, B. D., Brotherton, M. S., Cackett, E. M., Dalla Bontà, E., De Rosa, G., Ferland, G. J., Fian, C., Filippenko, A. V., Gelbord, J., Goad, M. R., Horne, K., …Zu, Y. (2024). AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations*. Astrophysical Journal, 972(2), Article 141. https://doi.org/10.3847/1538-4357/ad5ff4

AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817 (2024)
Journal Article
Homayouni, Y., Kriss, G. A., De Rosa, G., Plesha, R., Cackett, E. M., Goad, M. R., …Zu, Y. (2024). AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817. Astrophysical Journal, 963(2), Article 123. https://doi.org/10.3847/1538-4357/ad1be4

An intensive reverberation mapping campaign of the Seyfert 1 galaxy Mrk 817 using the Cosmic Origins Spectrograph on the Hubble Space Telescope revealed significant variations in the response of broad UV emission lines to fluctuations in the continuu... Read More about AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817.

First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548 (2024)
Journal Article
Mehdipour, M., Kriss, G. A., Kaastra, J. S., Costantini, E., Gu, L., Landt, H., …Rogantini, D. (2024). First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548. Astrophysical Journal, 962(2), Article 155. https://doi.org/10.3847/1538-4357/ad1bcb

Multiwavelength spectroscopy of NGC 5548 revealed remarkable changes due to the presence of an obscuring wind from the accretion disk. This broadened our understanding of obscuration and outflows in active galactic nuclei. Swift monitoring of NGC 554... Read More about First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548.

AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817 (2024)
Journal Article
Neustadt, J. M. M., Kochanek, C. S., Montano, J., Gelbord, J., Barth, A. J., De Rosa, G., …Zu, Y. (2024). AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817. Astrophysical Journal, 961(2), Article 219. https://doi.org/10.3847/1538-4357/ad1386

We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations δ T resolved in time and radius. The δ T maps are dominated by coherent radial structures that move slowly (v ≪ c) inward... Read More about AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817.

AGN STORM 2. IV. Swift X-Ray and Ultraviolet/Optical Monitoring of Mrk 817 (2023)
Journal Article
Cackett, E. M., Gelbord, J., Barth, A. J., De Rosa, G., Edelson, R., Goad, M. R., …Zaidouni, F. (2023). AGN STORM 2. IV. Swift X-Ray and Ultraviolet/Optical Monitoring of Mrk 817. Astrophysical Journal, 958(2), Article 195. https://doi.org/10.3847/1538-4357/acfdac

The AGN STORM 2 campaign is a large, multiwavelength reverberation mapping project designed to trace out the structure of Mrk 817 from the inner accretion disk to the broad emission line region and out to the dusty torus. As part of this campaign, Sw... Read More about AGN STORM 2. IV. Swift X-Ray and Ultraviolet/Optical Monitoring of Mrk 817.

The outer dusty edge of accretion disks in active galactic nuclei (2023)
Journal Article
Landt, H. (2023). The outer dusty edge of accretion disks in active galactic nuclei. Frontiers in Astronomy and Space Sciences, 10, 1256088. https://doi.org/10.3389/fspas.2023.1256088

Recent models for the inner structure of active galactic nuclei (AGN) aim at connecting the outer region of the accretion disk with the broad-line region and dusty torus through a radiatively accelerated, dusty outflow. Such an outflow not only requi... Read More about The outer dusty edge of accretion disks in active galactic nuclei.

Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories (2023)
Journal Article
Miller, J. A., Cackett, E. M., Goad, M. R., Horne, K., Barth, A. J., Romero-Colmenero, E., …Winkler, H. (2023). Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories. Astrophysical Journal, 953(2), Article 137. https://doi.org/10.3847/1538-4357/ace342

Continuum reverberation mapping probes the size scale of the optical continuum-emitting region in active galactic nuclei (AGN). Through 3 yr of multiwavelength photometric monitoring in the optical with robotic observatories, we perform continuum rev... Read More about Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories.

The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc (2023)
Journal Article
Mitchell, J. A. J., Done, C., Ward, M. J., Kynoch, D., Hagen, S., Lusso, E., & Landt, H. (2023). The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc. Monthly Notices of the Royal Astronomical Society, 524(2), 1796-1825. https://doi.org/10.1093/mnras/stad1830

We use the SOUX sample of ∼700 active galactic nucleus (AGN) to form average optical-ultraviolet (UV)-X-rays spectral energy distributions (SEDs) on a two-dimensional (2D) grid of MBH and L2500. We compare these with the predictions of a new AGN SED... Read More about The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc.