Staff profile

Journal Article

• Accretion disc reverberation mapping of the quasar 3C 273
  
  Thorne, J. P., Landt, H., Huang, J., Hernández Santisteban, J. V., Horne, K., Cackett, E. M., Winkler, H., & Sanmartim, D. (2025). Accretion disc reverberation mapping of the quasar 3C 273. Monthly Notices of the Royal Astronomical Society, 537(4), 3746-3768. https://doi.org/10.1093/mnras/staf258
• 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.
  
  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., … 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
• AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy
  
  Zaidouni, F., Kara, E., Kosec, P., Mehdipour, M., Rogantini, D., Kriss, G. A., Behar, E., Kaastra, J., Barth, A. J., Cackett, E. M., De Rosa, G., Homayouni, Y., Horne, K., Landt, H., Arav, N., Bentz, M. C., Brotherton, M. S., Dalla Bontà, E., Dehghanian, M., … Zu, Y. (2024). AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy. The Astrophysical Journal, 974(1), Article 91. https://doi.org/10.3847/1538-4357/ad6771
• 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
  
  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., … 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. The Astrophysical Journal, 974(2), 271. https://doi.org/10.3847/1538-4357/ad6b08
• AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations*
  
  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., … Zu, Y. (2024). AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations*. The Astrophysical Journal, 972(2), Article 141. https://doi.org/10.3847/1538-4357/ad5ff4
• First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548
  
  Mehdipour, M., Kriss, G. A., Kaastra, J. S., Costantini, E., Gu, L., Landt, H., Mao, J., & Rogantini, D. (2024). First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548. The Astrophysical Journal, 962(2), Article 155. https://doi.org/10.3847/1538-4357/ad1bcb
• AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817
  
  Neustadt, J. M. M., Kochanek, C. S., Montano, J., Gelbord, J., Barth, A. J., De Rosa, G., Kriss, G. A., Cackett, E. M., Horne, K., Kara, E. A., Landt, H., Netzer, H., Arav, N., Bentz, M. C., Dalla Bontà, E., Dehghanian, M., Du, P., Edelson, R., Ferland, G. J., … Zu, Y. (2024). AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817. The Astrophysical Journal, 961(2), Article 219. https://doi.org/10.3847/1538-4357/ad1386
• AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817
  
  Homayouni, Y., Kriss, G. A., De Rosa, G., Plesha, R., Cackett, E. M., Goad, M. R., Korista, K. T., Horne, K., Fischer, T., Waters, T., Barth, A. J., Kara, E. A., Landt, H., Arav, N., Boizelle, B. D., Bentz, M. C., Brotherton, M. S., Chelouche, D., Dalla Bontà, E., … Zu, Y. (2024). AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817. The Astrophysical Journal, 963(2), Article 123. https://doi.org/10.3847/1538-4357/ad1be4
• AGN STORM 2. IV. Swift X-Ray and Ultraviolet/Optical Monitoring of Mrk 817
  
  Cackett, E. M., Gelbord, J., Barth, A. J., De Rosa, G., Edelson, R., Goad, M. R., Homayouni, Y., Horne, K., Kara, E. A., Kriss, G. A., Korista, K. T., Landt, H., Plesha, R., Arav, N., Bentz, M. C., Boizelle, B. D., Dalla Bontà, E., Dehghanian, M., Donnan, F., … Zaidouni, F. (2023). AGN STORM 2. IV. Swift X-Ray and Ultraviolet/Optical Monitoring of Mrk 817. The Astrophysical Journal, 958(2), Article 195. https://doi.org/10.3847/1538-4357/acfdac
• The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc
  
  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
• Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories
  
  Miller, J. A., Cackett, E. M., Goad, M. R., Horne, K., Barth, A. J., Romero-Colmenero, E., Fausnaugh, M., Gelbord, J., Korista, K. T., Landt, H., Treu, T., & Winkler, H. (2023). Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories. The Astrophysical Journal, 953(2), Article 137. https://doi.org/10.3847/1538-4357/ace342
• AGN STORM 2. II. Ultraviolet Observations of Mrk 817 with the Cosmic Origins Spectrograph on the Hubble Space Telescope*
  
  Homayouni, Y., De Rosa, G., Plesha, R., Kriss, G. A., Barth, A. J., Cackett, E. M., Horne, K., Kara, E. A., Landt, H., Arav, N., Boizelle, B. D., Bentz, M. C., Brink, T. G., Brotherton, M. S., Chelouche, D., Dalla Bontà, E., Dehghanian, M., Du, P., Ferland, G. J., … Zu, Y. (2023). AGN STORM 2. II. Ultraviolet Observations of Mrk 817 with the Cosmic Origins Spectrograph on the Hubble Space Telescope*. Astrophysical Journal, 948(2), Article 85. https://doi.org/10.3847/1538-4357/acc45a
• AGN STORM 2. III. A NICER View of the Variable X-Ray Obscurer in Mrk 817
  
  Partington, E. R., Cackett, E. M., Kara, E., Kriss, G. A., Barth, A. J., De Rosa, G., Homayouni, Y., Horne, K., Landt, H., Zoghbi, A., Edelson, R., Arav, N., Boizelle, B. D., Bentz, M. C., Brotherton, M. S., Byun, D., Dalla Bontà, E., Dehghanian, M., Du, P., … Zaidouni, F. (2023). AGN STORM 2. III. A NICER View of the Variable X-Ray Obscurer in Mrk 817. Astrophysical Journal, 947(1), Article 2. https://doi.org/10.3847/1538-4357/acbf44
• The SOUX AGN sample: SDSS–XMM-Newton optical, ultraviolet, and X-ray selected active galactic nuclei spanning a wide range of parameter space – sample definition
  
  Kynoch, D., Mitchell, J. A. J., Ward, M. J., Done, C., Lusso, E., & Landt, H. (2023). The SOUX AGN sample: SDSS–XMM-Newton optical, ultraviolet, and X-ray selected active galactic nuclei spanning a wide range of parameter space – sample definition. Monthly Notices of the Royal Astronomical Society, 520(2), 2781-2805. https://doi.org/10.1093/mnras/stad221
• A Complex Dust Morphology in the High-luminosity AGN Mrk 876
  
  Landt, H., Mitchell, J. A., Ward, M. J., Mercatoris, P., Pott, J.-U., Horne, K., Hernández Santisteban, J. V., Malhotra, D., Cackett, E. M., Goad, M. R., Romero Colmenero, E., & Winkler, H. (2023). A Complex Dust Morphology in the High-luminosity AGN Mrk 876. Astrophysical Journal, 945(1), Article 62. https://doi.org/10.3847/1538-4357/acb92d
• The long-term broad-line responsivity in MKN 110
  
  Homan, D., Lawrence, A., Ward, M., Bruce, A., Landt, H., MacLeod, C., Elvis, M., Wilkes, B., Huchra, J. P., & Peterson, B. M. (2023). The long-term broad-line responsivity in MKN 110. Monthly Notices of the Royal Astronomical Society, 519(2), 1745-1763. https://doi.org/10.1093/mnras/stac3571
• The outer dusty edge of accretion disks in active galactic nuclei
  
  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
• Transient obscuration event captured in NGC 3227 III. Photoionization modeling of the X-ray obscuration event in 2019
  
  Mao, J., Kaastra, J., Mehdipour, M., Kriss, G., Wang, Y., Grafton-Waters, S., Branduardi-Raymont, G., Pinto, C., Landt, H., Walton, D., Costantini, E., Di Gesu, L., Bianchi, S., Petrucci, P.-O., De Marco, B., Ponti, G., Fukazawa, Y., Ebrero, J., & Behar, E. (2022). Transient obscuration event captured in NGC 3227 III. Photoionization modeling of the X-ray obscuration event in 2019. Astronomy & Astrophysics, 665, Article A72. https://doi.org/10.1051/0004-6361/202142637
• 10 Yr Transformation of the Obscuring Wind in NGC 5548
  
  Mehdipour, M., Kriss, G. A., Costantini, E., Gu, L., Kaastra, J. S., Landt, H., & Mao, J. (2022). 10 Yr Transformation of the Obscuring Wind in NGC 5548. The Astrophysical Journal Letters, 934(2). https://doi.org/10.3847/2041-8213/ac822f
• Detection of an unidentified soft X-ray emission feature in NGC 5548
  
  Gu, L., Mao, J., Kaastra, J. S., Mehdipour, M., Pinto, C., Grafton-Waters, S., Bianchi, S., Landt, H., Branduardi-Raymont, G., Costantini, E., Ebrero, J., Petrucci, P.-O., Behar, E., di Gesu, L., De Marco, B., Matt, G., Mitchell, J. A., Peretz, U., Ursini, F., & Ward, M. (2022). Detection of an unidentified soft X-ray emission feature in NGC 5548. Astronomy & Astrophysics, 665, Article A93. https://doi.org/10.1051/0004-6361/202244075
• AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
  
  Kara, E., Mehdipour, M., Kriss, G. A., Cackett, E. M., Arav, N., Barth, A. J., Byun, D., Brotherton, M. S., De Rosa, G., Gelbord, J., Hernández Santisteban, J. V., Hu, C., Kaastra, J., Landt, H., Li, Y.-R., Miller, J. A., Montano, J., Partington, E., Aceituno, J., … Zu, Y. (2021). AGN STORM 2. I. First results: A Change in the Weather of Mrk 817. Astrophysical Journal, 922(2), Article 151. https://doi.org/10.3847/1538-4357/ac2159
• Broad He i 1.08-µm absorption from the obscurer in the active galaxy NGC 5548
  
  Wildy, C., Landt, H., Ward, M. J., Czerny, B., & Kynoch, D. (2021). Broad He i 1.08-µm absorption from the obscurer in the active galaxy NGC 5548. Monthly Notices of the Royal Astronomical Society: Letters, 500(2), 2063-2075. https://doi.org/10.1093/mnras/staa3301
• State-of-the-art AGN SEDs for Photoionization Models: BLR Predictions Confront the Observations
  
  Ward, M. J., Landt, H., Jin, C., Done, C., & Ferland, G. J. (2020). State-of-the-art AGN SEDs for Photoionization Models: BLR Predictions Confront the Observations. Monthly Notices of the Royal Astronomical Society, 494(4), 5917-5922. https://doi.org/10.1093/mnras/staa1207
• The spectral energy distributions of active galactic nuclei
  
  Brown, M. J. I., Duncan, K. J., Landt, H., Kirk, M., Ricci, C., Kamraj, N., Salvato, M., & Ananna, T. (2019). The spectral energy distributions of active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 489(3), Article 3351. https://doi.org/10.1093/mnras/stz2324
• The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548
  
  Landt, H., Ward, M. J., Kynoch, D., Packham, C., Ferland, G. J., Lawrence, A., Pott, J.-U., Esser, J., Horne, K., Starkey, D. A., Malhotra, D., Fausnaugh, M. M., Peterson, B. M., Wilman, R. J., Riffel, R. A., Storchi-Bergmann, T., Barth, A. J., Villforth, C., & Winkler, H. (2019). The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548. Monthly Notices of the Royal Astronomical Society, 489(2), Article 1572. https://doi.org/10.1093/mnras/stz2212
• The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413
  
  Kynoch, D., Landt, H., Ward, M. J., Done, C., Boisson, C., Baloković, M., Angelakis, E., & Myserlis, I. (2019). The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413. Monthly Notices of the Royal Astronomical Society, 487(1), 181-197. https://doi.org/10.1093/mnras/stz1193
• Analyzing temporal variations of AGN emission line profiles in the context of (dusty) cloud structure formation in the broad line region
  
  Esser, J., Pott, J. U., Landt, H., & Vacca, W. D. (2019). Analyzing temporal variations of AGN emission line profiles in the context of (dusty) cloud structure formation in the broad line region. Astronomy and Astrophysics., 621. https://doi.org/10.1051/0004-6361/201834291
• The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342
  
  Kynoch, D., Landt, H., Ward, M. J., Done, C., Gardner, E., Boisson, C., Arrieta-Lobo, M., Zech, A., Steenbrugge, K., & Pereira Santaella, M. (2018). The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342. Monthly Notices of the Royal Astronomical Society, 475(1), 404-423. https://doi.org/10.1093/mnras/stx3161
• A Multi-band Study of the Remarkable Jet in Quasar 4C+19.44
  
  Harris, D. E., Lee, N. P., Schwartz, D. A., Siemiginowska, A., Massaro, F., Birkinshaw, M., Worrall, D. M., Cheung, C. C., Gelbord, J. M., Jorstad, S. G., Marscher, A. P., Landt, H., Marshall, H., Perlman, E. S., Stawarz, L., Uchiyama, Y., & Urry, C. M. (2017). A Multi-band Study of the Remarkable Jet in Quasar 4C+19.44. Astrophysical Journal, 846(2), Article 119. https://doi.org/10.3847/1538-4357/aa845c
• The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei
  
  García-Bernete, I., Ramos Almeida, C., Landt, H., Ward, M. .J., Baloković, M., & Acosta-Pulido, J. A. (2017). The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 469(1), 110-126. https://doi.org/10.1093/mnras/stx795
• BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission
  
  Lamperti, I., Koss, M., Trakhtenbrot, B., Schawinski, K., Ricci, C., Oh, K., Landt, H., Riffel, R., Rodríguez-Ardila, A., Gehrels, N., Harrison, F., Masetti, N., Mushotzky, R., Treister, E., Ueda, Y., & Veilleux, S. (2017). BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission. Monthly Notices of the Royal Astronomical Society, 467(1), 540-572. https://doi.org/10.1093/mnras/stx055
• Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy
  
  Collinson, J. S., Ward, M. J., Landt, H., Done, C., Elvis, M., & McDowell, J. C. (2017). Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy. Monthly Notices of the Royal Astronomical Society, 465(1), 358-382. https://doi.org/10.1093/mnras/stw2666
• On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342
  
  Landt, H., Ward, M. J., Baloković, M., Kynoch, D., Storchi-Bergmann, T., Boisson, C., Done, C., Schimoia, J., & Stern, D. (2017). On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342. Monthly Notices of the Royal Astronomical Society, 464(3), 2565-2576. https://doi.org/10.1093/mnras/stw2447
• The near-infrared broad emission line region of active galactic nuclei – II. The 1-μm continuum
  
  Landt, H., Martin, E., Ward, M. J., Bentz, M. C., Korista, K. T., & Karovska, M. (2011). The near-infrared broad emission line region of active galactic nuclei – II. The 1-μm continuum. Monthly Notices of the Royal Astronomical Society, 414(1), 218-240. https://doi.org/10.1111/j.1365-2966.2011.18383.x
• On the dust geometry in radio-loud active galactic nuclei.
  
  Landt, H., Buchanan, C., & Barmby, P. (2010). On the dust geometry in radio-loud active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 408(4), 1982-1997. https://doi.org/10.1111/j.1365-2966.2010.17264.x
• On the relationship between BL Lacertae objects and radio galaxies.
  
  Landt, H., & Bignall, H. E. (2008). On the relationship between BL Lacertae objects and radio galaxies. Monthly Notices of the Royal Astronomical Society, 391(2), 967-985. https://doi.org/10.1111/j.1365-2966.2008.13967.x
• A Search for Synchrotron X-Ray Emission in Radio Quasars
  
  Landt, H., Padovani, P., Giommi, P., Perri, M., & Cheung, C. C. (2008). A Search for Synchrotron X-Ray Emission in Radio Quasars. Astrophysical Journal, 676(1), 87-100. https://doi.org/10.1086/527531
• The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei. I. The Observations.
  
  Landt, H., Bentz, M. C., Ward, M. J., Elvis, M., Peterson, B. M., Korista, K. T., & Karovska, M. (2008). The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei. I. The Observations. Astrophysical Journal Supplement, 174(2), 282-312. https://doi.org/10.1086/522373