Transient obscuration event captured in NGC 3227: I. continuum model for the broadband spectral energy distribution

M. Mehdipour; G.A. Kriss; J.S. Kaastra; Y. Wang; J. Mao; E. Costantini; N. Arav; E. Behar; S. Bianchi; G. Branduardi-Raymont; M. Brotherton; M. Cappi; B. De Marco; L. Di Gesu; J. Ebrero; S. Grafton-Waters; S. Kaspi; G. Matt; S. Paltani; P.-O. Petrucci; C. Pinto; G. Ponti; F. Ursini; D.J. Walton

doi:10.1051/0004-6361/202141324

Transient obscuration event captured in NGC 3227: I. continuum model for the broadband spectral energy distribution

M. Mehdipour, G.A. Kriss, J.S. Kaastra, Y. Wang, J. Mao, E. Costantini, N. Arav, E. Behar, S. Bianchi, G. Branduardi-Raymont, M. Brotherton, M. Cappi, B. De Marco, L. Di Gesu, J. Ebrero, S. Grafton-Waters, S. Kaspi, G. Matt, S. Paltani, P.-O. PetrucciC. Pinto, G. Ponti, F. Ursini, D.J. Walton

Physics

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Abstract

From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and the HST Cosmic Origins Spectrograph in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST Space Telescope Imaging Spectrograph data, in order to disentangle various spectral components of NGC 3227 and recover the underlying continuum. We find the observed NIR-optical-UV continuum is explained well by an accretion disk blackbody component (Tmax=10 eV), which is internally reddened by E(B - V) = 0.45 with a Small Magellanic Cloud extinction law. We derive the inner radius (12 Rg) and the accretion rate (0.1 Myr-1) of the disk by modelling the thermal disk emission. The internal reddening in NGC 3227 is most likely associated with outflows from the dusty AGN torus. In addition, an unreddened continuum component is also evident, which likely arises from scattered radiation, associated with the extended narrow-line region of NGC 3227. The extreme ultraviolet continuum, and the 'soft X-ray excess', can be explained with a 'warm Comptonisation' component. The hard X-rays are consistent with a power-law and a neutral reflection component. The intrinsic bolometric luminosity of the AGN in NGC 3227 is about 2.2 × 1043 erg s-1 in 2019, corresponding to 3% Eddington luminosity. Our continuum modelling of the new triggered data of NGC 3227 requires the presence of a new obscuring gas with column density NH = 5 × 1022 cm-2, partially covering the X-ray source (Cf = 0.6).

Original language	English
Article number	A150
Number of pages	11
Journal	Astronomy and Astrophysics
Volume	652
DOIs	https://doi.org/10.1051/0004-6361/202141324
Publication status	Published - 26 Aug 2021

Funding

Acknowledgements. This work is based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). This research has made use of data obtained with the NuSTAR mission, a project led by the California Institute of Technology (Caltech), managed by the Jet Propulsion Laboratory (JPL) and funded by NASA. We thank the Swift team for monitoring our AGN sample, and the XMM-Newton, NuSTAR, and HST teams for scheduling our ToO triggered observations. This work was supported by NASA through a grant for HST program number 15673 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. SRON is supported financially by NWO, the Netherlands Organization for Scientific Research. J. M. acknowledges the support from STFC (UK) through the University of Strathclyde UK APAP network grant ST/R000743/1. S. B. acknowledges financial support from ASI under grants ASI-INAF I/037/12/0 and n. 2017-14-H.O. B. D. M. acknowledges support from Ramán y Cajal Fellowship RYC2018-025950-I. S. G. W. acknowledges the support of a PhD studentship awarded by the UK Science and Technology Facilities Council (STFC). P. O. P. acknowledges financial support from the CNES French space agency and the PNHE high energy national program of CNRS. G. P. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 865637). D. J. W. acknowledges support from STFC in the form of an Ernest Rutherford Fellowship. We thank the anonymous referee for the constructive comments.

Keywords

accretion
galaxies
active
spectroscopic
x-rays
accretion disks
Seyfert
NGC 3227

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Mehdipour, M., Kriss, G. A., Kaastra, J. S., Wang, Y., Mao, J., Costantini, E., Arav, N., Behar, E., Bianchi, S., Branduardi-Raymont, G., Brotherton, M., Cappi, M., De Marco, B., Di Gesu, L., Ebrero, J., Grafton-Waters, S., Kaspi, S., Matt, G., Paltani, S., ... Walton, D. J. (2021). Transient obscuration event captured in NGC 3227: I. continuum model for the broadband spectral energy distribution. Astronomy and Astrophysics, 652, Article A150. https://doi.org/10.1051/0004-6361/202141324

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abstract = "From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and the HST Cosmic Origins Spectrograph in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST Space Telescope Imaging Spectrograph data, in order to disentangle various spectral components of NGC 3227 and recover the underlying continuum. We find the observed NIR-optical-UV continuum is explained well by an accretion disk blackbody component (Tmax=10 eV), which is internally reddened by E(B - V) = 0.45 with a Small Magellanic Cloud extinction law. We derive the inner radius (12 Rg) and the accretion rate (0.1 Myr-1) of the disk by modelling the thermal disk emission. The internal reddening in NGC 3227 is most likely associated with outflows from the dusty AGN torus. In addition, an unreddened continuum component is also evident, which likely arises from scattered radiation, associated with the extended narrow-line region of NGC 3227. The extreme ultraviolet continuum, and the 'soft X-ray excess', can be explained with a 'warm Comptonisation' component. The hard X-rays are consistent with a power-law and a neutral reflection component. The intrinsic bolometric luminosity of the AGN in NGC 3227 is about 2.2 × 1043 erg s-1 in 2019, corresponding to 3\% Eddington luminosity. Our continuum modelling of the new triggered data of NGC 3227 requires the presence of a new obscuring gas with column density NH = 5 × 1022 cm-2, partially covering the X-ray source (Cf = 0.6). ",

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author = "M. Mehdipour and G.A. Kriss and J.S. Kaastra and Y. Wang and J. Mao and E. Costantini and N. Arav and E. Behar and S. Bianchi and G. Branduardi-Raymont and M. Brotherton and M. Cappi and \{De Marco\}, B. and \{Di Gesu\}, L. and J. Ebrero and S. Grafton-Waters and S. Kaspi and G. Matt and S. Paltani and P.-O. Petrucci and C. Pinto and G. Ponti and F. Ursini and D.J. Walton",

year = "2021",

month = aug,

day = "26",

doi = "10.1051/0004-6361/202141324",

language = "English",

volume = "652",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Mehdipour, M, Kriss, GA, Kaastra, JS, Wang, Y, Mao, J, Costantini, E, Arav, N, Behar, E, Bianchi, S, Branduardi-Raymont, G, Brotherton, M, Cappi, M, De Marco, B, Di Gesu, L, Ebrero, J, Grafton-Waters, S, Kaspi, S, Matt, G, Paltani, S, Petrucci, P-O, Pinto, C, Ponti, G, Ursini, F & Walton, DJ 2021, 'Transient obscuration event captured in NGC 3227: I. continuum model for the broadband spectral energy distribution', Astronomy and Astrophysics, vol. 652, A150. https://doi.org/10.1051/0004-6361/202141324

TY - JOUR

T1 - Transient obscuration event captured in NGC 3227

T2 - I. continuum model for the broadband spectral energy distribution

AU - Mehdipour, M.

AU - Kriss, G.A.

AU - Kaastra, J.S.

AU - Wang, Y.

AU - Mao, J.

AU - Costantini, E.

AU - Arav, N.

AU - Behar, E.

AU - Bianchi, S.

AU - Branduardi-Raymont, G.

AU - Brotherton, M.

AU - Cappi, M.

AU - De Marco, B.

AU - Di Gesu, L.

AU - Ebrero, J.

AU - Grafton-Waters, S.

AU - Kaspi, S.

AU - Matt, G.

AU - Paltani, S.

AU - Petrucci, P.-O.

AU - Pinto, C.

AU - Ponti, G.

AU - Ursini, F.

AU - Walton, D.J.

PY - 2021/8/26

Y1 - 2021/8/26

N2 - From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and the HST Cosmic Origins Spectrograph in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST Space Telescope Imaging Spectrograph data, in order to disentangle various spectral components of NGC 3227 and recover the underlying continuum. We find the observed NIR-optical-UV continuum is explained well by an accretion disk blackbody component (Tmax=10 eV), which is internally reddened by E(B - V) = 0.45 with a Small Magellanic Cloud extinction law. We derive the inner radius (12 Rg) and the accretion rate (0.1 Myr-1) of the disk by modelling the thermal disk emission. The internal reddening in NGC 3227 is most likely associated with outflows from the dusty AGN torus. In addition, an unreddened continuum component is also evident, which likely arises from scattered radiation, associated with the extended narrow-line region of NGC 3227. The extreme ultraviolet continuum, and the 'soft X-ray excess', can be explained with a 'warm Comptonisation' component. The hard X-rays are consistent with a power-law and a neutral reflection component. The intrinsic bolometric luminosity of the AGN in NGC 3227 is about 2.2 × 1043 erg s-1 in 2019, corresponding to 3% Eddington luminosity. Our continuum modelling of the new triggered data of NGC 3227 requires the presence of a new obscuring gas with column density NH = 5 × 1022 cm-2, partially covering the X-ray source (Cf = 0.6).

AB - From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and the HST Cosmic Origins Spectrograph in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST Space Telescope Imaging Spectrograph data, in order to disentangle various spectral components of NGC 3227 and recover the underlying continuum. We find the observed NIR-optical-UV continuum is explained well by an accretion disk blackbody component (Tmax=10 eV), which is internally reddened by E(B - V) = 0.45 with a Small Magellanic Cloud extinction law. We derive the inner radius (12 Rg) and the accretion rate (0.1 Myr-1) of the disk by modelling the thermal disk emission. The internal reddening in NGC 3227 is most likely associated with outflows from the dusty AGN torus. In addition, an unreddened continuum component is also evident, which likely arises from scattered radiation, associated with the extended narrow-line region of NGC 3227. The extreme ultraviolet continuum, and the 'soft X-ray excess', can be explained with a 'warm Comptonisation' component. The hard X-rays are consistent with a power-law and a neutral reflection component. The intrinsic bolometric luminosity of the AGN in NGC 3227 is about 2.2 × 1043 erg s-1 in 2019, corresponding to 3% Eddington luminosity. Our continuum modelling of the new triggered data of NGC 3227 requires the presence of a new obscuring gas with column density NH = 5 × 1022 cm-2, partially covering the X-ray source (Cf = 0.6).

KW - accretion

KW - galaxies

KW - active

KW - spectroscopic

KW - x-rays

KW - accretion disks

KW - Seyfert

KW - NGC 3227

UR - https://www.scopus.com/pages/publications/85114007703

U2 - 10.1051/0004-6361/202141324

DO - 10.1051/0004-6361/202141324

M3 - Article

AN - SCOPUS:85114007703

SN - 0004-6361

VL - 652

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A150

ER -

Transient obscuration event captured in NGC 3227: I. continuum model for the broadband spectral energy distribution

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Keywords

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