AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations

Maryam Dehghanian; Nahum Arav; Gerard A. Kriss; Missagh Mehdipour; Doyee Byun; Gwen Walker; Mayank Sharma; Aaron J. Barth; Misty C. Bentz; Benjamin D. Boizelle; Michael S. Brotherton; Edward M. Cackett; Elena Dalla Bontà; Gisella De Rosa; Gary J. Ferland; Carina Fian; Alexei V. Filippenko; Jonathan Gelbord; Michael R. Goad; Keith Horne; Yasaman Homayouni; Dragana Ilić; Michael D. Joner; Erin A. Kara; Shai Kaspi; Christopher S. Kochanek; Kirk T. Korista; Peter Kosec; Andjelka B. Kovačević; Hermine Landt; Collin Lewin; Ethan R. Partington; Luka Č. Popović; Daniel Proga; Daniele Rogantini; Matthew R. Siebert; Thaisa Storchi-Bergmann; Marianne Vestergaard; Timothy. Waters; Jian-Min Wang; Fatima Zaidouni; Ying Zu

doi:10.3847/1538-4357/ad5ff4

AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations

Maryam Dehghanian, Nahum Arav, Gerard A. Kriss, Missagh Mehdipour, Doyee Byun, Gwen Walker, Mayank Sharma, Aaron J. Barth, Misty C. Bentz, Benjamin D. Boizelle, Michael S. Brotherton, Edward M. Cackett, Elena Dalla Bontà, Gisella De Rosa, Gary J. Ferland, Carina Fian, Alexei V. Filippenko, Jonathan Gelbord, Michael R. Goad, Keith HorneYasaman Homayouni, Dragana Ilić, Michael D. Joner, Erin A. Kara, Shai Kaspi, Christopher S. Kochanek, Kirk T. Korista, Peter Kosec, Andjelka B. Kovačević, Hermine Landt, Collin Lewin, Ethan R. Partington, Luka Č. Popović, Daniel Proga, Daniele Rogantini, Matthew R. Siebert, Thaisa Storchi-Bergmann, Marianne Vestergaard, Timothy. Waters, Jian-Min Wang, Fatima Zaidouni, Ying Zu

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Abstract

We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s⁻¹ with FWHM = 177 km s⁻¹) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log N H = 19.5 _−0.13^+0.61 cm⁻²) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log U_H = −1.0 _−0.3^+0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of n H > 3000 cm⁻³. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 10¹⁶ cm), with potential cloud geometries ranging from spherical to elongated along the line of sight.

Original language	English
Article number	141
Number of pages	13
Journal	The Astrophysical Journal
Volume	972
Issue number	2
Early online date	3 Sept 2024
DOIs	https://doi.org/10.3847/1538-4357/ad5ff4
Publication status	Published - 10 Sept 2024

Keywords

Seyfert galaxies
Active galactic nuclei
Active galaxies

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Dehghanian-2024-AGN-STORM-2-VIII-ApJ-972-2-141-CCBY
Copyright © 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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https://arxiv.org/abs/2407.04164Licence: CC BY

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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

@article{bed1d88193d74a2ba14f5f75e662a889,

title = "AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations",

abstract = "We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s−1 with FWHM = 177 km s−1) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log N H = 19.5 −0.13+0.61 cm−2) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log UH = −1.0 −0.3+0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of n H > 3000 cm−3. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1016 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight.",

keywords = "Seyfert galaxies, Active galactic nuclei, Active galaxies",

author = "Maryam Dehghanian and Nahum Arav and Kriss, {Gerard A.} and Missagh Mehdipour and Doyee Byun and Gwen Walker and Mayank Sharma and Barth, {Aaron J.} and Bentz, {Misty C.} and Boizelle, {Benjamin D.} and Brotherton, {Michael S.} and Cackett, {Edward M.} and {Dalla Bont{\`a}}, Elena and {De Rosa}, Gisella and Ferland, {Gary J.} and Carina Fian and Filippenko, {Alexei V.} and Jonathan Gelbord and Goad, {Michael R.} and Keith Horne and Yasaman Homayouni and Dragana Ili{\'c} and Joner, {Michael D.} and Kara, {Erin A.} and Shai Kaspi and Kochanek, {Christopher S.} and Korista, {Kirk T.} and Peter Kosec and Kova{\v c}evi{\'c}, {Andjelka B.} and Hermine Landt and Collin Lewin and Partington, {Ethan R.} and Popovi{\'c}, {Luka {\v C}.} and Daniel Proga and Daniele Rogantini and Siebert, {Matthew R.} and Thaisa Storchi-Bergmann and Marianne Vestergaard and Timothy. Waters and Jian-Min Wang and Fatima Zaidouni and Ying Zu",

note = "Funding: H.L. acknowledges a Daphne Jackson Fellowship sponsored by the Science and Technology Facilities Council (STFC), UK.",

year = "2024",

month = sep,

day = "10",

doi = "10.3847/1538-4357/ad5ff4",

language = "English",

volume = "972",

journal = "The Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Dehghanian, M, Arav, N, Kriss, GA, Mehdipour, M, Byun, D, Walker, G, Sharma, M, Barth, AJ, Bentz, MC, Boizelle, BD, Brotherton, MS, Cackett, EM, Dalla Bontà, E, De Rosa, G, Ferland, GJ, Fian, C, Filippenko, AV, Gelbord, J, Goad, MR, Horne, K, Homayouni, Y, Ilić, D, Joner, MD, Kara, EA, Kaspi, S, Kochanek, CS, Korista, KT, Kosec, P, Kovačević, AB, Landt, H, Lewin, C, Partington, ER, Popović, LČ, Proga, D, Rogantini, D, Siebert, MR, Storchi-Bergmann, T, Vestergaard, M, Waters, T, Wang, J-M, Zaidouni, F & Zu, Y 2024, 'AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations', The Astrophysical Journal, vol. 972, no. 2, 141. https://doi.org/10.3847/1538-4357/ad5ff4

TY - JOUR

T1 - AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations

AU - Dehghanian, Maryam

AU - Arav, Nahum

AU - Kriss, Gerard A.

AU - Mehdipour, Missagh

AU - Byun, Doyee

AU - Walker, Gwen

AU - Sharma, Mayank

AU - Barth, Aaron J.

AU - Bentz, Misty C.

AU - Boizelle, Benjamin D.

AU - Brotherton, Michael S.

AU - Cackett, Edward M.

AU - Dalla Bontà, Elena

AU - De Rosa, Gisella

AU - Ferland, Gary J.

AU - Fian, Carina

AU - Filippenko, Alexei V.

AU - Gelbord, Jonathan

AU - Goad, Michael R.

AU - Horne, Keith

AU - Homayouni, Yasaman

AU - Ilić, Dragana

AU - Joner, Michael D.

AU - Kara, Erin A.

AU - Kaspi, Shai

AU - Kochanek, Christopher S.

AU - Korista, Kirk T.

AU - Kosec, Peter

AU - Kovačević, Andjelka B.

AU - Landt, Hermine

AU - Lewin, Collin

AU - Partington, Ethan R.

AU - Popović, Luka Č.

AU - Proga, Daniel

AU - Rogantini, Daniele

AU - Siebert, Matthew R.

AU - Storchi-Bergmann, Thaisa

AU - Vestergaard, Marianne

AU - Waters, Timothy.

AU - Wang, Jian-Min

AU - Zaidouni, Fatima

AU - Zu, Ying

N1 - Funding: H.L. acknowledges a Daphne Jackson Fellowship sponsored by the Science and Technology Facilities Council (STFC), UK.

PY - 2024/9/10

Y1 - 2024/9/10

N2 - We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s−1 with FWHM = 177 km s−1) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log N H = 19.5 −0.13+0.61 cm−2) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log UH = −1.0 −0.3+0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of n H > 3000 cm−3. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1016 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight.

AB - We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s−1 with FWHM = 177 km s−1) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log N H = 19.5 −0.13+0.61 cm−2) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log UH = −1.0 −0.3+0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of n H > 3000 cm−3. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1016 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight.

KW - Seyfert galaxies

KW - Active galactic nuclei

KW - Active galaxies

U2 - 10.3847/1538-4357/ad5ff4

DO - 10.3847/1538-4357/ad5ff4

M3 - Article

SN - 0004-637X

VL - 972

JO - The Astrophysical Journal

JF - The Astrophysical Journal

IS - 2

M1 - 141

ER -

AGN STORM 2. VIII. Investigating the narrow absorption lines in Mrk 817 using HST-COS observations

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