Powerful relativistic jets in spiral galaxies Luigi Luigi Fosc - - PowerPoint PPT Presentation

Powerful relativistic jets in spiral galaxies

Luigi Luigi Fosc

• schini

hini National Institute of Astrophysics (INAF) - Brera Astronomical Observatory Merate (LC), Italy Thanks to G. Ghisellini, L. Maraschi, F. Tavecchio for amusing discussions

Ar Artis tistic vie tic view b w by L. F y L. Fosc

• schini

hini

High-Ener High-Energy gy Phenomena Phenomena in in Relativis elativistic tic Outf Outflo lows III III – Bar Barcelona celona, 29 , 29 June June 20 2011 1

Main aim of this research: to understand relativistic jets. γ-NLS1s: a new class of γ-ray emitting AGN

NLS1s are not new AGN, since they were discovered more than 25 years ago, but are new as γ–ray emitters.

“The difference between the right word and the nearly right word is the difference between lightning and lightning-bug” (Mark Twain).

(Review: LF, 2011, Proc. NLS1 Milano, arXiv:1105.0772) Thanks to B. Giebels and P. Grandi, who introduced the topic in their Monday talks

Comparison with blazars in term of mass, accretion, jet power; Comparison with jets in Galactic binaries Hints on jets generation?

Some notes on LF, 2011, arxiv:1106.5532 (today on astro-ph!)

“You can observe a lot by just watching.” (Y. Berra)

2008 June 11: launch of Fermi/LAT… discovery of GeV γ rays from NLS1! PMN J0948+0022 a.k.a. SDSS J094857.31+002225.4 (0.5846) The first NLS1 detected at high-energy γ-rays (E > 100 MeV)

Found after the first months of Fermi operations (17σ): it is in the LAT Bright AGN Sample (LBAS), but erroneously classified as FSRQ Found to be radio-loud with flat spectrum and high brightness temperature by Zhou et al. (2003)

LF et al., 2010, in: “Accretion and Ejection in AGN: A Global View” [Blazar sequence from Fossati et al (1998) and Donato et al. (2001) Radio galaxies from Ghisellini et al. (2005)] Abdo et al. 2009 SED model described in detail in Ghisellini & Tavecchio (2009) Torus Disc Corona Syn self-abs

Two MW Campaigns on PMN J0948+0022

2009 March-July (Abdo et al. 2009):

• Triggered to better understand the nature of the

source;

• γ-ray activity in early April 2009 (peak ≈ 4×10-7

ph cm-2 s-1), followed by an increase of radio emission after ≈ 2 months;

• Confirmation of the association of the γ-ray

source with the NLS1 J0948+0022 by means of coordinated MW variability.

• Confirmed by detection of strong optical (V)

polarization (19%) with Kanata telescope (Ikejiri et

• al. 2011)

2010 July-September (LF et al. 2011):

• Triggered by the first observed γ-ray outburst

(peak ≈ 10-6 ph cm-2 s-1 ➤ L ≈ 1048 erg/s!);

• 90° swing of radio EVPA before burst;
• Extreme power (high Compton dominance),

when compared to the emission at other wavelengths.

2010 Sept 2010 Jan

OVRO (15 GHz) Sun (no visibility) ATOM (R) Fermi/LAT (0.1-100 GeV)

1 month bins 3 days bins

L≈1048 erg/s!

2010 July

Presently 7 γ-NLS1 are known

• 4 were detected in 12 months of Fermi/LAT data (Abdo et al. 2009)
• 3 new γ–NLS1 found in 30 months of LAT data (LF 2011). SBS 0846+513 recently confirmed also

by Fermi/LAT Collaboration (Atel 3452). More to come…

Very compact radio morphology

(a few tens of pc; except for PKS 0558-504 – Gliozzi et al. 2010)

1H 0323+342 (1.2 pc/mas) PKS 1502+036 (5.4 pc/mas) PMN J0948+0022 (6.6 pc/mas) SBS 0846+513 (6.6 pc/mas)

HST/WFPC2 (2x200 s) Adaptive smoothing (LF 2011)

Host Galaxies: spirals

HST observation of 1H 0323+342: Zhou et al. (2007): spiral morphology Anton et al. (2008): ring due to a recent merger

1H 0323+342 (z=0.061) VLBA (2cm/15 GHz) – MOJAVE Project (☞ http://www.physics.purdue.edu/MOJAVE/)

Orange stars: γ–NLS1 Red circles: FSRQ Blue squares and arrow (u.l.): BL Lac Objects Grey triangles: γ–Radio Galaxies

Powerful Relativistic Jets as a function of mass and accretion

LF (2011)

γ-NLS1s facts sheet

(Review: LF 2011)

• First detections at high-energy γ rays of NLS1 by using Fermi/LAT: 7 NLS1 detected to date;
• γ-ray detections are linked to the activity of the source ⇒ more discoveries expected.
• Typical relativistic jet behavior: observed correlated multiwavelength activity;
• The jets of γ-NLS1s are similar to those in blazars, but everything else is different:

γ-NLS1s Blazars FWHM Broad Lines ≲ 2000 km/s ≳ 2000 km/s SMBH Mass 106-108 M⊙ 108-1010 M⊙ Accretion rate 0.1-1 Eddington < 0.5 Eddington Host galaxy Spiral Elliptical Radio morphology Compact (< a few tens of pc) except for PKS 0558-504 Extended (even kpc-scale)

Part II: Comparison with blazars

• Data on 30 FSRQ and 9 BL Lac Objects from Ghisellini et al. 2010.
• Data on 4 γ-NLS1 from Abdo et al. 2009 and the 3 new from LF 2011.
• Radio data at 15 GHz from MOJAVE or from ATCA (for southern sources) at

8 or 18 GHz.

• Jet power calculated by means of the model by Ghisellini & Tavecchio, 2009
• Most masses and accretion rates from the optical/UV measurements, by

assuming a standard Shakura & Sunyaev (1973) accretion disc. Checked with literature (virial methods).

• Radio loudness calculated from the core radio data at 15 GHz and the disc

emission, as from above.

• FSRQ

◼ BL Lacs ★ γ-NLS1 Pjet [⇌ Lγ] ∝ L15GHz

(0.81±0.06)

Spearman’s ρ=0.8 (P<10-4)

L400MeV ∝ L8.4GHz

(0.77±0.03) [Bloom 2008]

L>100MeV ∝ L20GHz

(1.07±0.05) [Ghirlanda et al. 2011]

“Calibration” of Ghisellini & Tavecchio’s model

Pjet ∝ Lradio,core

(12/17) ≈ Lradio,core 0.71

Theory: Blandford & Königl (1979) Observations: Körding et al. (2006)

Sikora et al. (2007) Woo & Urry (2003) Very high accretion (0.1-1Edd) Very low accretion (<< 1%Edd)

Radio loudness vs Mass

• FSRQ

◼ BL Lacs ★ γ-NLS1 (★ new)

Sikora et al. (2007) Broderick & Fender (2011)

Radio loudness vs Accretion

• FSRQ

◼ BL Lacs ★ γ-NLS1 (★ new)

Is radio loudness still meaningful?

The sources with higher values of RL are BL Lac Objects, but they have low jet power. Low RL is associated with γ-NLS1s, but they have low jet power. The high (low) radio loudness seems to be linked more to low (high) accretion, rather than the jet power. So, who cares about radio loudness? Still useful as a first-order estimate of the presence or not of a jet.

Magnetospheric Jet Hydromagnetic Jet Magnetospheric driven jet Centrifugally driven jet Extraction of rotational energy: BH + disc Extraction of rotational energy: disc BH is needed; disc provide charges No need of a black hole, just a disc Blandford & Znajek (1977) Macdonald & Thorne (1982) “Precursors” Penrose (1969) Ruffini & Wilson (1975), Lovelace (1976) Blandford (1976) [analogy: Goldreich & Julian 1969 - Pulsars] Blandford & Payne (1982) “Precursors” Piddington (1970), Sturrock & Barnes (1972), Ozernoy & Usov (1973)

Pause: How to generate a relativistic jet?

Hybrid models (“Hydromagnetospheric”): Phinney (1983), Punsly & Coroniti (1990), Meier (1999); see also Garofalo et al. (2010)

Blandford-Znajek Luminosity

Moderski & Sikora (1996), Ghosh & Abramowicz (1997) BZ luminosity depends on the magnetic field at the horizon, which in turn is determined by the accretion disc regime (standard disc Shakura & Sunyaev 1973; Novikov & Thorne 1973):

Radiation-Pressure Dominated (RPD) Gas-Pressure Dominated (GPD)

Total Jet Power vs Mass

• FSRQ

◼ BL Lacs ★ γ-NLS1 (★ new)

GPD RPD

Ghisellini et al. (2011)

RPD

• FSRQ

◼ BL Lacs ★ γ-NLS1 (★ new)

Ldisc ∝ ˙ m

2

Ldisc ∝ ˙ m

Total Jet Power vs Accretion GPD

Pjet,rad > LBZ

Luminosity ratio Jet/Max BZ vs Accretion

(BZ calculated according to Ghosh & Abramowicz 1997 with J/Jmax=1)

• FSRQ

◼ BL Lacs ★ γ-NLS1 Pjet,rad < LBZ J/Jmax=0.3

Hydromagnetic wind contribution? (winds in RG, Tombesi et al. 2010) Scenario Cavaliere & D’Elia (2002): BZ as backbone + hybridization as accretion increases

Lradio ∝ Ldisc

0.6

Ldisc ∝ ˙ m

2−3

Lradio ∝ Ldisc

1.4

Ldisc ∝ ˙ m

Difference in Ldisc (accretion): 9 orders of magnitudes ⬇ Roughly, the mass difference Difference in Lradio (jet power): 14 orders of magnitudes! ⬇ More than the mass difference… Why? Galactic binaries (black holes, neutron stars) from Coriat et al. (2011)

• Cf. Elena Gallo’s talk of yesterday

AGN (blazars, γ-NLS1s)

• FSRQ

◼ BL Lacs ★ γ-NLS1 (★ new)

Work in progress…