The nature of LINER nuclei

Isabel Márquez (IAA-CSIC, Granada, Spain)

Josefa Masegosa (IAA, CSIC) Omaira González-Martín (IAC)

Lorena Hernández (IAA, CSIC)

Jose Acosta (IAC)

Jose M. Rodríguez-Espinosa (IAC)

Almudena Alonso-Herrero (IFCA)

Rachel Mason (Gemini)

Séminaire du Luth, 12 Décembre 2013

1.Introduction: Properties

LINERs vs LIERs

2. AGN nuclear LINERs:

spectral properties and variability

LINERs at Mid-IR Star Formation in LINERs

3. Conclusions

OVERVIEW

INTRODUCTION

LINERs: Low Ionization Emission-line Regions Spectral Classification (Heckman 1980)

- Optical spectra Dominated by emission lines from low ionization species ([OI],[NII][SII])

- Early types

- Lower luminosities than Seyferts

- Continuity ionization state and electron temperature

Connecti

on with

AGN

AGNs (Active Galactic Nuclei) : - high luminosities - very compact regions - usually temporaly variable (from hours to years) more efficient energy/mass than normal stellar processes (Fabian 79)

1. High Luminosity AGNs : Accretion onto a SMBH

2. Low luminosity AGNs (LLAGN) - most of AGN population- eventual connection

active/non-active nuclei

BUT, difficult detection due to extinction and contamination by circumnuclear star formation.

INTRODUCTION

INTRODUCTIONUnification scheme cartoon: Urry and Padovany (1995)

INTRODUCTION: LINE RATIOSHo (2008)

Warning: broad line LINERs must be AGN poweredLINERs 1.8 (Ho et al. 1997)

INTRODUCTION. LINERs SEDs

Ho (2008)

INTRODUCTION: Their hostsSAMPLE:

Palomar Sky Survey (LOCAL)

LINERs:

from E to Sb,

irrespective of the interaction class

(Márquez et al. 2010)

INTRODUCTION: Their hosts

HII

Comp

Seyf

LINER

Cid-Fernandes+11

Kewley06Kauffmann03

Passive red galaxies

(0.09 < z < 0.1)

are mostly LINERs

(color-cut selected)

(Yan et al. 2012)

INTRODUCTION:LINERs @ MIR

Sturm et al (2006)- First well defined spectroscopic study of LINERs at MIR (5-35µm)

“IR-luminous LINERs show mid-IR SEDs typical of starburst galaxies, while the mid-IR SEDs of IR-faint LINERs are much bluer.”

LINERs @ MIR

X-RAY – MIR RELATIONS

Systematic study with VISIR/VLT (0.35” resolution)

(Horst+2006,2008, 2009, Ghandi+2010,

Asmus+2011)

● MIR-X-ray correlation for Seyferts is also valid for the LLAGN

● Results disfavors star formation as the dominant MIR source in LLAGN

● MIR-X-ray luminosity ratio is independent of the accretion rate

“Increasing the sample size, in particular for the LINERs, would lead to much tighter constraints on the nature of the MIR emission in LLAGN.” (Asmus 2011)

LINERs @ MIR

High L/Ledd

Low L/Ledd

Radio quiet

Radio loud

Mason et al. 2012

INTRODUCTION.Excitation Mechanisms - Non Stellar Photoionization

(Osterbrock 1959, Ferland & Netzer 1983, Halpern & Steiner 1983,Ho,Filipenko & Sargent 1993, Groves,Dopita & Sutherland 2004)

- Shock induced

(Dopita & Sutherland 1996, Aldrovandi & Contini, Kewley+2001)

- Stellar Photoionization

(Terlevich, Melnick 1985, Binette+1994, Stasinska+2008, Sarzi+2010)

Cid-Fernandes+(2011)

8%

18%

31%

22%

21%

19%

37%

23%21%

INTRODUCTION:STAR FORMATION IN LINERs

Masegosa et al (2004)- IRAS Data for LINERs in Carrillo's catalogue

1. Normal spiral galaxies 1. Normal spiral galaxies

2. Galaxies with enhanced star formation2. Galaxies with enhanced star formation STARBURST -like

3. Galaxias with VERY HIGH SFR up to 200Galaxias with VERY HIGH SFR up to 200 Interacting systems,Interacting systems, ULIRGs LINERs

(Masegosa & Márquez 2003, Surace et al 2003)

Starbursts LINERs

Sy 2 Sy 1

S12/S25 > 0.60

S12/S25 < 0.60

INTRODUCTION:STAR FORMATION IN LINERs

González-Delgado+2004, Cid-Fernández + 2003:

stellar pop. synthesis. STIS spectra (20-100 pc),

2/11 LINERs with ages

younger than 108 yr.

Sarzi+05:

23 gxs, HST spectra

“Our findings reinforce the picture wherein Seyfert nuclei and the majority of low-ionization nuclear emission-line regions are predominantly accretion-powered”

STAR FORMATION IN LINERsTommasin+2012

LINERs from zCOSMOS

z ~ 0.3

L(IR) from

- Higher AGN luminosities

but...

INTRODUCTION.LIERS (non-nuclear LINERs)

Kehrig+ 12NGC 5966

Vstars (km/s) σ(Hα) (km/s) v(Hα) (km/s)

(see also

Papaderos+12,

Singh+ 13)

SB Kewley+01Sy/LINER Kewley+06

Shock grid Allen+08AGN phot. Grooves+04

pAGB Binette+94

INTRODUCTION.LIERS (non-nuclear LINERs)

NGC 5850Bremer+13

AGN-powered nucleus?Line asymmetries

AGN LINERs: X-raysWhy LINERs are so Dim with BH masses of 108 - 109 Mo ????

LOW ACCRETION RATES ?

OBSCURATION?(Gonzalez-Martín+ 2009b)

● Compton-thin LINERs

◦Compton-thick candidates

Compton-thin Sy

Compton-thick Sy

Sy1 from Panessa+06

log(MBH) =

8.22 ± 0.65

SAMPLE: from multiwavelength catalogue

of 476 LINERs (Carrillo + 1999)

FINAL: 82 LINERs

68 with Chandra,

54 with XMM-Newton

(40 in common)

Gonzalez-Martín's PhD thesis

Gonzalez Martín et al (2006a, 2009a, 2009b)

AGN LINERs: X-rays

AGN LINERs: X-rays

AGN candidate: With a point-like source at 4.5-8.0keV

Non-AGN candidate: Without point-like source at 4.5-8.0keV

48/82 (60%)

34/82(40%)

AGN LINERs: X-rays

X-ray spectral fitting:

MEPL, two absorbersГ = 2.11 (σ =0.52)kT = 0.54 (σ =0.52)

log NH1 = 21.32 (σ =0.71)log NH2 = 21.93 (σ =1.36)

(González-Martín+2009a)

NH2NH1 NH2

AGN LINERs: X-rays

LINERS: 63% Compton-thick

(52/82)

Seyfert 2: 23% Compton thick

(Panessa et al.2006)

The origin of such obscuration is crucial to relate LLAGN to HLAGN

Compton thick indicator

L([OIII])/L(2-10 keV) Compton-thick

Seyfert 2

LINERs

UnobscuredQSOs

(González-Martín+2009b)

AGN LINERs: X-ray variability

First evidences of variability:

In UV, Maoz et al. (2005): 14/17 LINERs varied in time scales from months to years In X-rays: Pian et al. (2010): 2/4 variable at short (hrs) and long time scales (yrs). Younes et al. (2011): long term flux variations in 7/9 L1.8 González-Martín et al. (2011): ”soft excess” variability in NGC 4102

González-Martín & Vaughan (2012): short time scale variations in 2/14 LINERs. Hernández-García et al (2013): long time scale variations in 4/7

AGN LINERs: X-ray variability

Sample: 16 AGN-LINERs with multiepoch üXMM-Newton and/or Chandra observations7 L1.8-1.9 , 9 L2 Model:

wabs[NHgal](zwabs[NH1]*mekal[kT,Norm1] +

zwabs[NH2]*plaw[gamma,Norm2])

- 4/7 L1, 4/9 L2 vary (50%)- Flux variations due to Norm2 and NH2

Hernández-García +, in prep.

AGN LINERs: MIR

4/12 LINERs detected with VISIR (40mJy)

7 LINERs from Gemini (T-ReCs ) (7mJy)

Morphology:

● Most unresolved at 0.35” resolution

● 4/11 extended

González-Martín et al. 2012

AGN LINERs: MIR

► The MIR observed emission is concentrated and in most cases unresolved at 0.35” resolution (~100pc)

► LINERs follow the MIR-X-ray correlation found for the general AGN population

IONIZED GAS IN LINERs

Hα HST imaging:

32 LINERs

Hα imaging

of (multi-λ)

confirmed AGN

favour

core-halo

and

outflow

morphologies

(65%)(Masegosa+2011)

CONCLUSIONS

LINERs powered by different mechanisms

Some are genuinous AGN

Nuclear LINERS as AGN : 90%

(bias: selection effect at X rays)

Unimportant recent SF, caveat: two families?

higher z?? (resolution)

Similar to Sys :

(BH, Edd rates, NH, MID-IR)

IMPORTANT caveat => Compton thichness

(more frequent)