HST/COS observations of the newly discovered obscuring outflow in NGC 3783

G. A. Kriss, M. Mehdipour, J. S. Kaastra, A. Rau, J. Bodensteiner, R. Plesha, N. Arav, E. Behar, S. Bianchi, G. Branduardi-Raymont, M. Cappi, E. Costantini, B. De Marco, L. Di Gesu, J. Ebrero, S. Kaspi, J. Mao, R. Middei, T. Miller, S. Paltani & 7 others U. Peretz, B. M. Peterson, P. O. Petrucci, G. Ponti, F. Ursini, D. J. Walton, X. Xu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Aims. To understand the nature of transient obscuring outflows in active galactic nuclei, we use simultaneous multiwavelength observations with XMM-Newton, NuSTAR, the Hubble Space Telescope (HST), and the Max Planck Gesellschaft/European Southern Observatory (ESO) 2.2 m telescope triggered by soft X-ray absorption detected by Swift. Methods. We obtained ultraviolet spectra on 2016-12-12 and 2016-12-21 using the Cosmic Origins Spectrograph (COS) on HST simultaneously with X-ray spectra obtained with XMM-Newton and NuSTAR. We modeled the ultraviolet spectra to measure the strength and variability of the absorption, and used photoionization models to obtain its physical characteristics. Results. We find new components of broad, blue-shifted absorption associated with Lyα, Nâ V, Siâ IV, and Câ IV in our COS spectra. The absorption extends from near-zero velocities in the rest-frame of the host galaxy to-6200 km s -1 . These features appear for the first time in NGC 3783 at the same time as heavy soft X-ray absorption seen in the XMM-Newton X-ray spectra. The X-ray absorption has a column density of ∼10 23 cm -2 , and it partially covers the X-ray continuum source. Combining the X-ray column densities with the UV spectral observations yields an ionization parameter for the obscuring gas of log ξ = 1.84 -0.2 +0.4 erg cm s -1 . Despite the high intensity of the UV continuum in NGC 3783, F(1470 Å) = 8â ×â 10 -14 erg cm -2 s -1 Å -1 >, the well known narrow UV absorption lines are deeper than in earlier observations in unobscured states, and low ionization states such as Câ III appear, indicating that the narrow-line gas is more distant from the nucleus and is being shadowed by the gas producing the obscuration. Despite the high continuum flux levels in our observations of NGC 3783, moderate velocities in the UV broad line profiles have substantially diminished. Conclusions.We suggest that a collapse of the broad line region has led to the outburst and triggered the obscuring event.

Original languageEnglish
Article numberA12
Number of pages24
JournalAstronomy and Astrophysics
Volume621
Early online date19 Dec 2018
DOIs
Publication statusE-pub ahead of print - 19 Dec 2018

Fingerprint

Hubble Space Telescope
spectrographs
outflow
XMM-Newton telescope
x rays
newton
ultraviolet spectra
continuums
erg
ionization
gases
gas
occultation
European Southern Observatory
active galactic nuclei
outburst
photoionization
observatory
telescopes
galaxies

Keywords

  • galaxies: active
  • galaxies: individual: NGC 3783
  • galaxies: Seyfert
  • quasars: absorption lines
  • quasars: emission lines
  • ultraviolet: galaxies

Cite this

Kriss, G. A., Mehdipour, M., Kaastra, J. S., Rau, A., Bodensteiner, J., Plesha, R., ... Xu, X. (2018). HST/COS observations of the newly discovered obscuring outflow in NGC 3783. Astronomy and Astrophysics, 621, [A12]. https://doi.org/10.1051/0004-6361/201834326
Kriss, G. A. ; Mehdipour, M. ; Kaastra, J. S. ; Rau, A. ; Bodensteiner, J. ; Plesha, R. ; Arav, N. ; Behar, E. ; Bianchi, S. ; Branduardi-Raymont, G. ; Cappi, M. ; Costantini, E. ; De Marco, B. ; Di Gesu, L. ; Ebrero, J. ; Kaspi, S. ; Mao, J. ; Middei, R. ; Miller, T. ; Paltani, S. ; Peretz, U. ; Peterson, B. M. ; Petrucci, P. O. ; Ponti, G. ; Ursini, F. ; Walton, D. J. ; Xu, X. / HST/COS observations of the newly discovered obscuring outflow in NGC 3783. In: Astronomy and Astrophysics. 2018 ; Vol. 621.
@article{fb75a0d832bd48b69de192fc71fbd2db,
title = "HST/COS observations of the newly discovered obscuring outflow in NGC 3783",
abstract = "Aims. To understand the nature of transient obscuring outflows in active galactic nuclei, we use simultaneous multiwavelength observations with XMM-Newton, NuSTAR, the Hubble Space Telescope (HST), and the Max Planck Gesellschaft/European Southern Observatory (ESO) 2.2 m telescope triggered by soft X-ray absorption detected by Swift. Methods. We obtained ultraviolet spectra on 2016-12-12 and 2016-12-21 using the Cosmic Origins Spectrograph (COS) on HST simultaneously with X-ray spectra obtained with XMM-Newton and NuSTAR. We modeled the ultraviolet spectra to measure the strength and variability of the absorption, and used photoionization models to obtain its physical characteristics. Results. We find new components of broad, blue-shifted absorption associated with Lyα, N{\^a} V, Si{\^a} IV, and C{\^a} IV in our COS spectra. The absorption extends from near-zero velocities in the rest-frame of the host galaxy to-6200 km s -1 . These features appear for the first time in NGC 3783 at the same time as heavy soft X-ray absorption seen in the XMM-Newton X-ray spectra. The X-ray absorption has a column density of ∼10 23 cm -2 , and it partially covers the X-ray continuum source. Combining the X-ray column densities with the UV spectral observations yields an ionization parameter for the obscuring gas of log ξ = 1.84 -0.2 +0.4 erg cm s -1 . Despite the high intensity of the UV continuum in NGC 3783, F(1470 {\AA}) = 8{\^a} ×{\^a} 10 -14 erg cm -2 s -1 {\AA} -1 >, the well known narrow UV absorption lines are deeper than in earlier observations in unobscured states, and low ionization states such as C{\^a} III appear, indicating that the narrow-line gas is more distant from the nucleus and is being shadowed by the gas producing the obscuration. Despite the high continuum flux levels in our observations of NGC 3783, moderate velocities in the UV broad line profiles have substantially diminished. Conclusions.We suggest that a collapse of the broad line region has led to the outburst and triggered the obscuring event.",
keywords = "galaxies: active, galaxies: individual: NGC 3783, galaxies: Seyfert, quasars: absorption lines, quasars: emission lines, ultraviolet: galaxies",
author = "Kriss, {G. A.} and M. Mehdipour and Kaastra, {J. S.} and A. Rau and J. Bodensteiner and R. Plesha and N. Arav and E. Behar and S. Bianchi and G. Branduardi-Raymont and M. Cappi and E. Costantini and {De Marco}, B. and {Di Gesu}, L. and J. Ebrero and S. Kaspi and J. Mao and R. Middei and T. Miller and S. Paltani and U. Peretz and Peterson, {B. M.} and Petrucci, {P. O.} and G. Ponti and F. Ursini and Walton, {D. J.} and X. Xu",
year = "2018",
month = "12",
day = "19",
doi = "10.1051/0004-6361/201834326",
language = "English",
volume = "621",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

Kriss, GA, Mehdipour, M, Kaastra, JS, Rau, A, Bodensteiner, J, Plesha, R, Arav, N, Behar, E, Bianchi, S, Branduardi-Raymont, G, Cappi, M, Costantini, E, De Marco, B, Di Gesu, L, Ebrero, J, Kaspi, S, Mao, J, Middei, R, Miller, T, Paltani, S, Peretz, U, Peterson, BM, Petrucci, PO, Ponti, G, Ursini, F, Walton, DJ & Xu, X 2018, 'HST/COS observations of the newly discovered obscuring outflow in NGC 3783', Astronomy and Astrophysics, vol. 621, A12. https://doi.org/10.1051/0004-6361/201834326

HST/COS observations of the newly discovered obscuring outflow in NGC 3783. / Kriss, G. A.; Mehdipour, M.; Kaastra, J. S.; Rau, A.; Bodensteiner, J.; Plesha, R.; Arav, N.; Behar, E.; Bianchi, S.; Branduardi-Raymont, G.; Cappi, M.; Costantini, E.; De Marco, B.; Di Gesu, L.; Ebrero, J.; Kaspi, S.; Mao, J.; Middei, R.; Miller, T.; Paltani, S.; Peretz, U.; Peterson, B. M.; Petrucci, P. O.; Ponti, G.; Ursini, F.; Walton, D. J.; Xu, X.

In: Astronomy and Astrophysics, Vol. 621, A12, 19.12.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - HST/COS observations of the newly discovered obscuring outflow in NGC 3783

AU - Kriss, G. A.

AU - Mehdipour, M.

AU - Kaastra, J. S.

AU - Rau, A.

AU - Bodensteiner, J.

AU - Plesha, R.

AU - Arav, N.

AU - Behar, E.

AU - Bianchi, S.

AU - Branduardi-Raymont, G.

AU - Cappi, M.

AU - Costantini, E.

AU - De Marco, B.

AU - Di Gesu, L.

AU - Ebrero, J.

AU - Kaspi, S.

AU - Mao, J.

AU - Middei, R.

AU - Miller, T.

AU - Paltani, S.

AU - Peretz, U.

AU - Peterson, B. M.

AU - Petrucci, P. O.

AU - Ponti, G.

AU - Ursini, F.

AU - Walton, D. J.

AU - Xu, X.

PY - 2018/12/19

Y1 - 2018/12/19

N2 - Aims. To understand the nature of transient obscuring outflows in active galactic nuclei, we use simultaneous multiwavelength observations with XMM-Newton, NuSTAR, the Hubble Space Telescope (HST), and the Max Planck Gesellschaft/European Southern Observatory (ESO) 2.2 m telescope triggered by soft X-ray absorption detected by Swift. Methods. We obtained ultraviolet spectra on 2016-12-12 and 2016-12-21 using the Cosmic Origins Spectrograph (COS) on HST simultaneously with X-ray spectra obtained with XMM-Newton and NuSTAR. We modeled the ultraviolet spectra to measure the strength and variability of the absorption, and used photoionization models to obtain its physical characteristics. Results. We find new components of broad, blue-shifted absorption associated with Lyα, Nâ V, Siâ IV, and Câ IV in our COS spectra. The absorption extends from near-zero velocities in the rest-frame of the host galaxy to-6200 km s -1 . These features appear for the first time in NGC 3783 at the same time as heavy soft X-ray absorption seen in the XMM-Newton X-ray spectra. The X-ray absorption has a column density of ∼10 23 cm -2 , and it partially covers the X-ray continuum source. Combining the X-ray column densities with the UV spectral observations yields an ionization parameter for the obscuring gas of log ξ = 1.84 -0.2 +0.4 erg cm s -1 . Despite the high intensity of the UV continuum in NGC 3783, F(1470 Å) = 8â ×â 10 -14 erg cm -2 s -1 Å -1 >, the well known narrow UV absorption lines are deeper than in earlier observations in unobscured states, and low ionization states such as Câ III appear, indicating that the narrow-line gas is more distant from the nucleus and is being shadowed by the gas producing the obscuration. Despite the high continuum flux levels in our observations of NGC 3783, moderate velocities in the UV broad line profiles have substantially diminished. Conclusions.We suggest that a collapse of the broad line region has led to the outburst and triggered the obscuring event.

AB - Aims. To understand the nature of transient obscuring outflows in active galactic nuclei, we use simultaneous multiwavelength observations with XMM-Newton, NuSTAR, the Hubble Space Telescope (HST), and the Max Planck Gesellschaft/European Southern Observatory (ESO) 2.2 m telescope triggered by soft X-ray absorption detected by Swift. Methods. We obtained ultraviolet spectra on 2016-12-12 and 2016-12-21 using the Cosmic Origins Spectrograph (COS) on HST simultaneously with X-ray spectra obtained with XMM-Newton and NuSTAR. We modeled the ultraviolet spectra to measure the strength and variability of the absorption, and used photoionization models to obtain its physical characteristics. Results. We find new components of broad, blue-shifted absorption associated with Lyα, Nâ V, Siâ IV, and Câ IV in our COS spectra. The absorption extends from near-zero velocities in the rest-frame of the host galaxy to-6200 km s -1 . These features appear for the first time in NGC 3783 at the same time as heavy soft X-ray absorption seen in the XMM-Newton X-ray spectra. The X-ray absorption has a column density of ∼10 23 cm -2 , and it partially covers the X-ray continuum source. Combining the X-ray column densities with the UV spectral observations yields an ionization parameter for the obscuring gas of log ξ = 1.84 -0.2 +0.4 erg cm s -1 . Despite the high intensity of the UV continuum in NGC 3783, F(1470 Å) = 8â ×â 10 -14 erg cm -2 s -1 Å -1 >, the well known narrow UV absorption lines are deeper than in earlier observations in unobscured states, and low ionization states such as Câ III appear, indicating that the narrow-line gas is more distant from the nucleus and is being shadowed by the gas producing the obscuration. Despite the high continuum flux levels in our observations of NGC 3783, moderate velocities in the UV broad line profiles have substantially diminished. Conclusions.We suggest that a collapse of the broad line region has led to the outburst and triggered the obscuring event.

KW - galaxies: active

KW - galaxies: individual: NGC 3783

KW - galaxies: Seyfert

KW - quasars: absorption lines

KW - quasars: emission lines

KW - ultraviolet: galaxies

UR - http://www.scopus.com/inward/record.url?scp=85059461127&partnerID=8YFLogxK

UR - https://arxiv.org/pdf/1810.12206.pdf

U2 - 10.1051/0004-6361/201834326

DO - 10.1051/0004-6361/201834326

M3 - Article

VL - 621

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A12

ER -

Kriss GA, Mehdipour M, Kaastra JS, Rau A, Bodensteiner J, Plesha R et al. HST/COS observations of the newly discovered obscuring outflow in NGC 3783. Astronomy and Astrophysics. 2018 Dec 19;621. A12. https://doi.org/10.1051/0004-6361/201834326