Discovery of a fast, broad, transient outflow in NGC 985

Ebrero, J.; Kriss, G. A.; Kaastra, J. S.; Ely, Justin

doi:10.1051/0004-6361/201527495

Cited by 50 publications

(73 citation statements)

References 23 publications

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“…This source is also known as Mrk 1048. Krongold et al (2009) and Ebrero et al (2016) have detected ionized absorption in X-rays in this source, similar to our findings. The black hole mass has been obtained using the Hβ emission line width (Koss et al 2011).…”

Section: Ngc 0985supporting

confidence: 93%

An X-ray view of central engines of low-luminosity quasars (LLQSO) in the local Universe

Laha

Ghosh

Guainazzi

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We have carried out a systematic X-ray spectral analysis of a sample of low luminosity quasars (LLQSO) to investigate the nature of the central engines of these sources. The opticallyselected LLQSO sample consists of close, known bright active galactic nuclei (AGN) which serves as an important link between the powerful quasars at higher redshift and local Seyfert galaxies. We find that although the bolometric luminosities of the LLQSOs are lower than those of the higher redshift quasars by almost an order of magnitude, their distribution of the Eddington rate λ Edd is similar. We detect a strong anti-correlation between α OX and L 2500Å , as has also been detected in several other quasar studies with large sample sizes, indicating that as the UV luminosity of the source increases, the X-ray luminosity decreases. We do not detect any significant neutral obscuration (N H 10 22 cm −2 ) in the X-ray spectra of the LLQSOs, and hence rule out obscuration as a possible cause for their lower luminosity. We conclude that the central engines of the LLQSOs function similarly to those of the higher redshift quasars, and the difference is possibly because of the fact that the LLQSOs have lower black hole masses. We do not find any correlation between the molecular gas in the host galaxies and accretion states of the AGN. This indicates that the presence of molecular gas in the host galaxies of the LLQSOs does not significantly influence the instantaneous accretion rates of their SMBHs.

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Section: Ngc 0985supporting

confidence: 93%

An X-ray view of central engines of low-luminosity quasars (LLQSO) in the local Universe

Laha

Ghosh

Guainazzi

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…The X-ray light curves of MCG-6-30-15 (McKernan & Yaqoob 1998) and NGC 3516 ) have been captured during dips whose profiles are characteristic of occultation events, also indicative of absorption close to BLR radii. Similar X-ray absorption events have also been found in Mrk 335 (Longinotti et al 2013), NGC 5548 (Kaastra et al 2014) and NGC 985 (Ebrero et al 2016). X-ray spectral data have been particularly valuable, as they can trace variability in spectral features, such as in the Note.…”

Section: Introductionsupporting

confidence: 77%

A rapid occultation event in NGC 3227

Turner

Reeves

Braito

et al. 2018

Monthly Notices of the Royal Astronomical Society

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NGC 3227 exhibits rapid flux and spectral variability in the X-ray band. To understand this behaviour we conducted a co-ordinated observing campaign using 320 ks of XMM-Newton exposures together with 160 ks of overlapping NuSTAR observations, spanning a month. Here, we present a rapid variability event that occurs toward the end of the campaign. The spectral hardening event is accompanied by a change in the depth of an unresolved transition array, whose time-dependent behaviour is resolved using the RGS data. This UTA fingerprint allows us to identify this as a transit event, where a clump of gas having N H ∼ 5 × 10 22 atoms cm −2 , log ξ ∼ 2 occults ∼ 60% of the continuum photons over the course of approximately a day. This occulting gas is likely associated with clouds in the inner BLR. An additional zone of gas with lower column and higher ionization, matches the outflow velocity of the variable zone, and may represent transmission through the cloud limb.

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“…Our UV spectra of NGC 3783 obtained with HST/COS in simultaneity with XMM-Newton X-ray observations triggered with Swift by a soft X-ray obscuration event reveal that the obscurer is a fast, broad outflow similar in character to those recently discovered in NGC 5548 (Kaastra et al 2014), Mrk 335 (Longinotti et al 2013), and NGC 985 (Ebrero et al 2016). The outflow extends from zero velocity to a maximum velocity of −6200 km s −1 , with a maximum depth at −3000 km s −1 , and a mean depth at −2840 km s −1 .…”

Section: Discussionsupporting

confidence: 77%

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

Kriss

Mehdipour

Kaastra

et al. 2018

A&A

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Context.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 December 12 and 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 v, Si iv, and C iv in our COS spectra. The absorption extends from velocities near zero 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 +0.4 −0.2 erg cm s −1 . Despite the high intensity of the UV continuum in NGC 3783, F(1470 Å)=8 × 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 C 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.

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Discovery of a fast, broad, transient outflow in NGC 985

Cited by 50 publications

References 23 publications

An X-ray view of central engines of low-luminosity quasars (LLQSO) in the local Universe

An X-ray view of central engines of low-luminosity quasars (LLQSO) in the local Universe

A rapid occultation event in NGC 3227

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

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