X ray obscurers: bridging the gap between warm

absorbers and ultra-fast outflowsJelle S. Kaastra

SRON Netherlands Institute for Space Research &

Leiden University

Ehud Behar, Stefano Bianchi, Graziella Branduardi-Raymont, Massimo Cappi, Elisa Costantini, Barbara de Marco, Laura di Gesu, Jacobo Ebrero, Jerry Kriss, Junjie Mao, Missagh

Mehdipour, Uria Peretz, Pierre-Olivier Petrucci, Gabriele Ponti, Dom Walton

1. First high-resolution spectrum of an AGN

2

NGC 5548, 11 December 1999, 86 ks, Chandra LETGSBlueshifted absorption lines from photoionised gas: wind

(Kaastra et al. 2000)

What have we learned from study of these winds?

• Relatively persistent features, variability through ionisation changes

• Multiple velocity components 0 – 1000 km/s• Multiple ionization phases log 𝜉 from 0 – 4• Moderate column density NH< 1027 m-2

• Majority of ionising photons transmitted• In some cases @ distance of torus(review see e.g. Blustin et al. 2005; Laha et al. 2014)

3

2. Ultra-fast outflows

4

PDS 456 – Nardini et al. 2015v = -75000 km/s

PG 1211+143 – Kriss et al. 2018v = -17000 km/s

UFO’s

• strongly transient phenomenon• velocities 10 000 – 100 000 km/s• high ionisation: log 𝜉 from 3 – 5• high column density: NH ~ 1026 – 1028 m-2

• majority of ionising photons transmitted• large covering factor?• Likely close to the black hole (102 – 104 RS)• Large kinetic power

(See e.g. Tombesi et al. 2011, 2012)

5

3. Obscuration in NGC 5548

6

1 10 1000.1

110

100

Pho

tons

m−2

s−1

Å−1

Energy (keV)

Chandra 2002

NuSTAR 2013

INTEGRAL 2013

pn 2013

RGS 2013

Kaastra et al. 2014

Properties of the obscuring matter

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• Outflowing with v=5000 km/s, broad profile• Two components:• Comp 1: log ξ = -1.2, NH=1026 m-2,

produces UV Broad Absorption Lines• Comp 2: almost neutral, NH=1027 m-2

• Partial covering inner BLR è distance few light days• Obscuration ongoing already for 8 years

Geometry of obscurers

8Credit: Renaud Person

Dehghanian et al. 2019

Effects of obscuration

9

1 102 5 200

0.2

0.4

0.6

0.8

1

Tran

smis

sion

Restframe wavelength (Å)

Total obscurer and WA 2013Obscurer 2013WA 2013WA 2002

• Modifies transmission WA due to recombination (de-ionisation)

• Modifies EUV SED èimplications for BLR modeling

• Shielding effect allows acceleration (UV-driven)

• At low X-ray resolution, neglect obscuration would lead to wrong continuum

Another case: NGC 3783

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• Joint XMM-Newton/HST/NuSTAR/Swift• ToO in Dec 2016

See Mehdipour et al. 2017

Recurring obscuration in NGC 3783

11

1 10

110

Phot

ons

m−2

s−1

Å−1

Wavelength (Å)

22−8−2016

102 5 20

110

100

Phot

ons

m−2

s−1

Å−1

Wavelength (Å)

1993

1996

2000 (x 2)

Moderate obscuration, NH 10x lower than in Dec 2016, but still 2x1026 m-2

(Kaastra et al. 2018)

HETGS

NuSTAR

Obscuration

ASCA

Obscuration

Obscuration frequency

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2.03.04.05.06.07.0

10−1

4 erg

cm

−2 s

−1 AÅ

−1

NGC 3783 SwiftUVOT (UVW2)

0.00.20.40.60.81.01.21.4

coun

t s−1

XRT (Soft)XRT (Hard)

0 50 100 150 200 250 300 350 400 450 500 550 6000Days − 57500 MJD (22/04/2016)

−0.20.00.20.40.60.81.0

(H−S

) / (H

+S)

0 50 100 150 200 250 300 350 400 450 500 550 6000Days − 57500 MJD (22/04/2016)

−0.20.00.20.40.60.81.0

(H−S

) / (H

+S) XRT X−ray HRMay−Jun

2014Jan−Feb2009

Jan−Feb2008

Swift hardness NGC 3783

Sparse info on how often and in how many AGN obscuration occurs

Some best-studied cases:NGC 5548 (Kaastra et al. 2014)NGC 3783 (Mehdipour et al. 2017)Mrk 335 (Longinotti et al. 2013)NGC 985 (Ebrero et al. 2016)NGC 3227 (Turner et al. 2018)

Obscured

notobscured

Summary & conclusions

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v (km/s) log 𝜉 log NH Shielding Distance

“Warm absorber”

300 0-3 <27 low large

Obscurer 3000 <0 <27 high medium

UFO 30000 3-5 <28 low small

Simplified representation

• Obscuring material has large impact on its environment

• likely part of disk wind, close to BLR• Physics complex due to strong shielding• Simultaneous UV/X-ray spectroscopy is key• Obscuration cannot be ignored in modelling

Credit: Renaud Person