Incoherent fast variability of X-ray obscurers. The case of NGC 3783

B. De Marco, T. P. Adhikari, G. Ponti, S. Bianchi, G. A. Kriss, N. Arav, E. Behar, G. Branduardi-Raymont, M. Cappi, E. Costantini, D. Costanzo, L. di Gesu, J. Ebrero, J. S. Kaastra, S. Kaspi, J. Mao, A. Markowitz, G. Matt, M. Mehdipour, R. Middei & 5 others S. Paltani, P. O. Petrucci, C. Pinto, A. Różańska, D. J. Walton

Research output: Contribution to journalArticle

Abstract

Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray spectral-timing analysis of the December 2016 obscuration event in NGC 3783, aimed at probing variability of the X-ray obscurer on the shortest possible timescales. The main goals of this study are to obtain independent constraints on the density, and ultimately on the distance of the obscuring gas, as well as to characterise the impact of variable obscuration on the observed X-ray spectral-timing characteristics of Seyfert galaxies. Methods. We carried out a comparative analysis of NGC 3783 during unobscured (using archival 2000-2001 XMM-Newton data) and obscured states (using XMM-Newton and NuSTAR data from the 2016 observational campaign). The timescales analysed range between ten hours and about one hour. This study was then generalized to discuss the signatures of variable obscuration in the X-ray spectral-timing characteristics of Seyfert galaxies as a function of the physical properties of the obscuring gas. Results. The X-ray obscurer in NGC 3783 is found to vary on timescales between about one hour to ten hours. This variability is incoherent with the variations of the X-ray continuum. A fast response (on timescales shorter than about 1.5 ks) of the ionisation state of the obscuring gas to the short timescale variability of the primary X-ray continuum provides a satisfactory interpretation of all the observed X-ray spectral-timing properties. This study enabled us to put independent constraints on the density and location of the obscuring gas. We found the gas to have a density of $n_{e}> 7.1 \times 10^7 \rm{cm^{-3}}$, consistent with being part of the broad line region.
Original languageEnglish
JournalAstronomy and Astrophysics
Early online date6 Dec 2019
DOIs
Publication statusE-pub ahead of print - 6 Dec 2019

Fingerprint

occultation
x rays
Seyfert galaxies
timescale
time measurement
gas
gases
XMM-Newton telescope
continuums
newton
ionization
gas ionization
clumps
spectral analysis
physical property
physical properties
signatures

Keywords

  • X-rays
  • galaxies
  • Seyfert galaxies
  • low ionisation gas

Cite this

Marco, B. D., Adhikari, T. P., Ponti, G., Bianchi, S., Kriss, G. A., Arav, N., ... Walton, D. J. (2019). Incoherent fast variability of X-ray obscurers. The case of NGC 3783. Astronomy and Astrophysics. https://doi.org/10.1051/0004-6361/201936470
Marco, B. De ; Adhikari, T. P. ; Ponti, G. ; Bianchi, S. ; Kriss, G. A. ; Arav, N. ; Behar, E. ; Branduardi-Raymont, G. ; Cappi, M. ; Costantini, E. ; Costanzo, D. ; Gesu, L. di ; Ebrero, J. ; Kaastra, J. S. ; Kaspi, S. ; Mao, J. ; Markowitz, A. ; Matt, G. ; Mehdipour, M. ; Middei, R. ; Paltani, S. ; Petrucci, P. O. ; Pinto, C. ; Różańska, A. ; Walton, D. J. / Incoherent fast variability of X-ray obscurers. The case of NGC 3783. In: Astronomy and Astrophysics. 2019.
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abstract = "Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray spectral-timing analysis of the December 2016 obscuration event in NGC 3783, aimed at probing variability of the X-ray obscurer on the shortest possible timescales. The main goals of this study are to obtain independent constraints on the density, and ultimately on the distance of the obscuring gas, as well as to characterise the impact of variable obscuration on the observed X-ray spectral-timing characteristics of Seyfert galaxies. Methods. We carried out a comparative analysis of NGC 3783 during unobscured (using archival 2000-2001 XMM-Newton data) and obscured states (using XMM-Newton and NuSTAR data from the 2016 observational campaign). The timescales analysed range between ten hours and about one hour. This study was then generalized to discuss the signatures of variable obscuration in the X-ray spectral-timing characteristics of Seyfert galaxies as a function of the physical properties of the obscuring gas. Results. The X-ray obscurer in NGC 3783 is found to vary on timescales between about one hour to ten hours. This variability is incoherent with the variations of the X-ray continuum. A fast response (on timescales shorter than about 1.5 ks) of the ionisation state of the obscuring gas to the short timescale variability of the primary X-ray continuum provides a satisfactory interpretation of all the observed X-ray spectral-timing properties. This study enabled us to put independent constraints on the density and location of the obscuring gas. We found the gas to have a density of $n_{e}> 7.1 \times 10^7 \rm{cm^{-3}}$, consistent with being part of the broad line region.",
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author = "Marco, {B. De} and Adhikari, {T. P.} and G. Ponti and S. Bianchi and Kriss, {G. A.} and N. Arav and E. Behar and G. Branduardi-Raymont and M. Cappi and E. Costantini and D. Costanzo and Gesu, {L. di} and J. Ebrero and Kaastra, {J. S.} and S. Kaspi and J. Mao and A. Markowitz and G. Matt and M. Mehdipour and R. Middei and S. Paltani and Petrucci, {P. O.} and C. Pinto and A. R{\'o}żańska and Walton, {D. J.}",
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Marco, BD, Adhikari, TP, Ponti, G, Bianchi, S, Kriss, GA, Arav, N, Behar, E, Branduardi-Raymont, G, Cappi, M, Costantini, E, Costanzo, D, Gesu, LD, Ebrero, J, Kaastra, JS, Kaspi, S, Mao, J, Markowitz, A, Matt, G, Mehdipour, M, Middei, R, Paltani, S, Petrucci, PO, Pinto, C, Różańska, A & Walton, DJ 2019, 'Incoherent fast variability of X-ray obscurers. The case of NGC 3783', Astronomy and Astrophysics. https://doi.org/10.1051/0004-6361/201936470

Incoherent fast variability of X-ray obscurers. The case of NGC 3783. / Marco, B. De; Adhikari, T. P.; Ponti, G.; Bianchi, S.; Kriss, G. A.; Arav, N.; Behar, E.; Branduardi-Raymont, G.; Cappi, M.; Costantini, E.; Costanzo, D.; Gesu, L. di; Ebrero, J.; Kaastra, J. S.; Kaspi, S.; Mao, J.; Markowitz, A.; Matt, G.; Mehdipour, M.; Middei, R.; Paltani, S.; Petrucci, P. O.; Pinto, C.; Różańska, A.; Walton, D. J.

In: Astronomy and Astrophysics, 06.12.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Incoherent fast variability of X-ray obscurers. The case of NGC 3783

AU - Marco, B. De

AU - Adhikari, T. P.

AU - Ponti, G.

AU - Bianchi, S.

AU - Kriss, G. A.

AU - Arav, N.

AU - Behar, E.

AU - Branduardi-Raymont, G.

AU - Cappi, M.

AU - Costantini, E.

AU - Costanzo, D.

AU - Gesu, L. di

AU - Ebrero, J.

AU - Kaastra, J. S.

AU - Kaspi, S.

AU - Mao, J.

AU - Markowitz, A.

AU - Matt, G.

AU - Mehdipour, M.

AU - Middei, R.

AU - Paltani, S.

AU - Petrucci, P. O.

AU - Pinto, C.

AU - Różańska, A.

AU - Walton, D. J.

PY - 2019/12/6

Y1 - 2019/12/6

N2 - Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray spectral-timing analysis of the December 2016 obscuration event in NGC 3783, aimed at probing variability of the X-ray obscurer on the shortest possible timescales. The main goals of this study are to obtain independent constraints on the density, and ultimately on the distance of the obscuring gas, as well as to characterise the impact of variable obscuration on the observed X-ray spectral-timing characteristics of Seyfert galaxies. Methods. We carried out a comparative analysis of NGC 3783 during unobscured (using archival 2000-2001 XMM-Newton data) and obscured states (using XMM-Newton and NuSTAR data from the 2016 observational campaign). The timescales analysed range between ten hours and about one hour. This study was then generalized to discuss the signatures of variable obscuration in the X-ray spectral-timing characteristics of Seyfert galaxies as a function of the physical properties of the obscuring gas. Results. The X-ray obscurer in NGC 3783 is found to vary on timescales between about one hour to ten hours. This variability is incoherent with the variations of the X-ray continuum. A fast response (on timescales shorter than about 1.5 ks) of the ionisation state of the obscuring gas to the short timescale variability of the primary X-ray continuum provides a satisfactory interpretation of all the observed X-ray spectral-timing properties. This study enabled us to put independent constraints on the density and location of the obscuring gas. We found the gas to have a density of $n_{e}> 7.1 \times 10^7 \rm{cm^{-3}}$, consistent with being part of the broad line region.

AB - Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray spectral-timing analysis of the December 2016 obscuration event in NGC 3783, aimed at probing variability of the X-ray obscurer on the shortest possible timescales. The main goals of this study are to obtain independent constraints on the density, and ultimately on the distance of the obscuring gas, as well as to characterise the impact of variable obscuration on the observed X-ray spectral-timing characteristics of Seyfert galaxies. Methods. We carried out a comparative analysis of NGC 3783 during unobscured (using archival 2000-2001 XMM-Newton data) and obscured states (using XMM-Newton and NuSTAR data from the 2016 observational campaign). The timescales analysed range between ten hours and about one hour. This study was then generalized to discuss the signatures of variable obscuration in the X-ray spectral-timing characteristics of Seyfert galaxies as a function of the physical properties of the obscuring gas. Results. The X-ray obscurer in NGC 3783 is found to vary on timescales between about one hour to ten hours. This variability is incoherent with the variations of the X-ray continuum. A fast response (on timescales shorter than about 1.5 ks) of the ionisation state of the obscuring gas to the short timescale variability of the primary X-ray continuum provides a satisfactory interpretation of all the observed X-ray spectral-timing properties. This study enabled us to put independent constraints on the density and location of the obscuring gas. We found the gas to have a density of $n_{e}> 7.1 \times 10^7 \rm{cm^{-3}}$, consistent with being part of the broad line region.

KW - X-rays

KW - galaxies

KW - Seyfert galaxies

KW - low ionisation gas

UR - https://arxiv.org/abs/1911.12772v1

U2 - 10.1051/0004-6361/201936470

DO - 10.1051/0004-6361/201936470

M3 - Article

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

ER -