06/10/2004seminar of the astronomuical institute 1 revision of blazars’ nature objects with binary...

06/10/2004 Seminar of the Astronomuical Institute

1

Revision of Blazars’ Nature Revision of Blazars’ Nature Objects with Binary SupermassiveObjects with Binary Supermassive

Black HoleBlack Hole

BaBašštata, M., M.Astronomical Institute, Academy of Sciences of the Czech RepublicAstronomical Institute, Academy of Sciences of the Czech Republic

Supervisor: RNDr. R. Hudec, CSc. (ASU AV, CR)Supervisor: RNDr. R. Hudec, CSc. (ASU AV, CR)Consultant: doc. A. Sillanpaa (Tuorla, Finland)Consultant: doc. A. Sillanpaa (Tuorla, Finland)

Hello everyone, welcome to my

lecture


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Outline of this lecture

• What AGN and blazars are• What basic properties of blazars are• About our blazar sample for which we

suggest supermassive binary black hole should be present

• How we probe the binary nature of blazars and explain the observed behavior

I will tell you . . .

At first, let us talk about Active galactic nuclei (=AGN). We will see that blazars

are just a class of AGN.


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Active Galactic Nuclei (= AGN) in pictures

Seyfert galaxy NGC5194

Radio galaxy Centaurus A

Quasar 3C 273Blazar Mkn 421


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Active Galactic Nuclei (= AGN)

Active Galactic Nuclei (AGN) powerful luminosity; non-stellar spectrum; high variability; BH engine; differ in luminosity, spectra, variability, morphology;1 - 10 % of galaxies supposed to be AGN

• Quasars Quasi stellar radio sources, powerful, radio loud vs. quiet

• Blazars Highly variable

• Radio galaxies Powerful in radio, radio lobes, elliptical

• Seyfert galaxies Spiral, luminous center, SG I vs. SG II

• LINERs, Nuclear HII Regions Specific energy production

• Strong IRAS & starburst galaxies Star formation

Observational classification of AGN


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Engine of AGN & AGN Unification I

Coming closer to AGN

Decreasing the angle between observer and jet

Radiolobes

Dustytorus

Black hole + Accretiondisk

CygnusA

CentaurusA

Blazar3C 273


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Engine of AGN & AGN Unification II

Seyfert 2 galaxy

Seyfert 1 galaxy

Radio galaxyQuasar

Radio loud(strong jets)

vs.

Radio quiet(weak jets)

Blazar

Black hole+ Accretion disk

Jet !!!

Torus

Antonucci, 1993


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Blazars & their powerful jet

Line of sight

Blazar observer

Supermassive black holewith accretion disc

Jet = Beam of energetic particles and magnetic

field moving close to the speed of light!!

Effects of the small angle between observer and jet:• Featureless continuum• Relativistic beaming• High luminosity• Superluminal motion• Gamma rays• Rapid variability


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Standard model of blazar = one supermassive black hole

“Standard model” =One supermassive

black hole

According to theUnification model(Antonucci, 1993)there is ONE supermassive black hole in the center of a blazar.


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Secondary black hole

Accretion disk

Jet

Primary black hole

• Volonteri et al., 2003BBHs should be common• There is observational evidence for BBHs

However, there are quite a lot of suggestions that not ONE black hole but TWO are present in several blazars . . .

Artist’s conception of a supermassive binary black hole (= BBH) system


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1. ON 231Possible periodicities:• 13.6 years in optical (Liu et al., 1995)

2. Mkn 421Possible periodicities: • 23 years in the optical band (Liu et al., 1997)• 104 second variations in the X-ray band (Marashi et al., 1999)

3. 0109+224Possible periodicities:• Long-term oscillations of the base-level flux on a timescale of

about 11.6 years (Smith & Nair, 1995)

4. Mkn 501Possible periodicities:• 23 days in the X-ray and TeV band (Nishikawa et al., 1999)

We have gathered following

suggestions for periodicity in our

blazar sample.

Our blazar sample for grant proposal (Part I)


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5. Mkn 766Possible periodicities: • 4200 seconds in the X-ray band (Boller et al., 2001)

6. 3C 345Possible periodicities:• 5 and 11 years in the optical band (Caproni & Abraham, 2004)

7. AO 0235+16Possible periodicities:• 5.7 years in the radio light curve (Raiteri et al., 2001)• 2.95 years in the optical light curve (Fan et al., 2002)

8. 3C 279Possible periodicities:• 7.1 years in the long-term near infrared light curve (Fan, 1999)• 22-year period from movement of jet components (Abraham &

Carrara, 1998)

Our blazar sample for grant proposal (Part II)


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9. PKS 0420-014Possible periodicities:• 13-months betweenoptical major outbursts(Wagner et al., 1995)

10. 0716+714Possible periodicities: • 0.7-year quasi-periodic ejection of VLBA components (Jorstad et al., 2001)• 12.5, 2.5 & 0.14-day periodicity of polarization in the optical band (Impey

et al., 2000)• 4-day periodicity in the optical band (Heidt & Wagner, 1996)

11. 3C 66aPossible periodicities:• 2.5 years (Belokon & Babadzhanyants, 2003), 275 and 64 days in

the optical band (Marchenko, 1999; Lainela et al., 1999)

The periodicity in the blazars may be

a suggestion of binary black hole

systems.

Our blazar sample for grant proposal (Part III)


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Origin of Binary Black Holes (= BBHs)

Hibbard & van Gorkom, 1996

The origin of the binary black hole system is in the merging of galaxies.

If each galaxy contains a supermassive black hole a binary black hole system is formed (frequent in clusters)


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Observational evidence for BBH systems

Hubble, optical Chandra, X-ray• NGC 6240

• High-redshift quasars observed in pairsQ1343.4+2640, LBQS0103-2753, UM425,...Komossa, 2003

True pairs x Chance alignments x Lensing effect

Komossa et al.,2003


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The periods in our “grant proposal” sample of 11 blazars are not confirmed at all as their light curves are not well-sampled and do not involve much historical data.

1. Gathering of optical data• Photographic plate collections

• Sonneberg Observatory, Germany (280 000 plates)• Harvard College Observatory, USA (600 000 plates)• UKSTU plate collection ROE Edinburgh, UK (18 000 plates)• Observatory Leiden, NL (40 000 plates)

• Papers• Observational campaigns archives

2. Gathering support data from other energy bands3. Periodicity analysis of the optical light curve4. An overall analysis to adopt a BBH model5. Establishing statistical results based on our sample of 11

blazars

We apply the following steps in our work:


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Possible origin of periods in blazars

It is necessary to watch out for the whole spectrum behavior and for the behavior of colors and flares to be able to distinguish between different origin

of periods in blazars.


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Blazars & support data from other bands

Blazar emit their energy from radio to TeV band. Data in all wavelength enable to specify the nature of blazars.

Spectral energy distribution of blazars


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Optical data gathering & Periodicity analysis

• Stellingwerf’s method (folded light curves)• Deeming method• CLEAN algorithm• Wavelets analysis

Sonneberg photographic plate

Determination of magnitude of a specific object in individual plates

Sextractor processing

Modified Argelander method

Sextractor screenshot

Thousands of photographic plates

ANALYSIS OF THE TIME SERIES


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Violent optical variability of BL Lac on a long time time scale


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We present a short introduction into the interpretation of periods using the supermassive binary black hole

scenario and the following designation:

angle between jet and observer M mass of the primary BH m mass of the secondary BHTorbital orbital period rm separation of black holes Lorenz factor of the jet vjet/capparent apparent z redshift

• There is wide range of possible interpretations of periods found in the light curves (in different bands).

21Seminar of the Astronomuical Institute

06/10/2004

Periodicity interpretation – origin in jet I

Time: t.(1-v/c.cos)

obsP

z

TT observedreal

1

2 2

Periods originating in the jet can be drastically shortened due to relativistic effects and small viewing angles:

Direction to

the observer

Directi

on of

the j

et ou

tflow

Angle between direction to observer and jet

Tobserved is any observed period originating in jet


06/10/2004

Periodicity interpretation – origin in jet II

Time: t.(1-v/c.cos)

obsP

max_apparent

The Lorenz factor can be estimated i.e. from superluminal motion.

cos1

sin

apparent

Apparent speeds higher than c are observed in the jet

The max. apparent speed can be used as an estimate of .

2/122

]1[,1

2

z

TT observedreal

From optical or VLBI measurements

Typical values of 10-15


06/10/2004

Periodicity interpretation – origin in jet III

obsP

The period observed in the jet may be induced i.e. by the tidal effect of the secondary black hole on the accretion disk of the primary.

1

3

))](cos1([)(

)'()(),(

tt

IttI emmitedobserved

cos1

4

33

dmprecession

real

r

GmT

Figure credit: Romero, Fan & Nuza, 2003


06/10/2004

Periodicity interpretation – origin in jet IV

obsP

The periods originating in the jet period may be also caused by:• knots rotating in the jet• emission from jet carried by the secondary BH

• components moving in helically distorted jets


06/10/2004

Periodicity interpretation – origin in the accretion disk

obsP

The secondary BH crosses twice the disk

•While the secondary is piercing a channel into the accretion disk of the primary the gas gets heated and radiates.•Timing of the outbursts enables the determination of the orbital period.• Color behavior may support or reject the origin of the periodicity in disk!!

The origin of the period in disk may be the case of blazar OJ 287:“Predicting the next outburst of OJ 287”, Valtonen, M.; Lehto, H. . . . Hudec, R.; Basta, M . . ., in preparation for ApJ


06/10/2004

Determination of the mass of the primary via high energy data support

obsP

Estimates of the mass of the primary black hole can be sometimes obtained using the high energy data.

Dsolar

TzM

M

1105 2

Estimating and measuring variability timescales in gamma-ray band gives an estimate of the mass of the primary black hole.

e+, e--ray

X-ray


06/10/2004

Determination of the mass of the secondary from periodicity studies

Time: t.(1-v/c.cos)

obsP

Stages of evolution of a BBH system:Dynamical friction stage Non-hard binary stage Hard-binary stage Gravitational radiation stage: The loss of energy via gravitational radiation results in the orbit decay

2

23

2

4

3

5

4

)(,

1

)(256

5~

/

orbitalm

m

TMmGr

Mm

mM

Mm

r

G

c

dtdr

r

Knowing Torbital , M and errors in determination of Torbital, can lead to an estimate of the upper limit of m.


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We participate in a paper in preparation where a specific model was applied to the blazar OJ 287.

Predicting the next outburst of OJ 287Valtonen, M.; Lehto, H.; . . Hudec, R.; Basta, M; . . In preparation for ApJ

OJ 287 light curve Scalegram for OJ 287


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Conclusion and future plans•It is highly possible that the engine of blazars and AGN is not associated with one supermassive black hole but with two supermassive black holes.

•Periodicity studies supported by data from other energy bands and supported by spectral/color and flare behavior may helpto establish a viable model.

•Our studies are based on gathering the data for a larger sample of blazars and carrying out the appropriate analysis, results discussion and establishing a new model of blazar.

• We have applied our approach fully already to OJ 287. The processing of other blazars is in the stage of data gathering and period analysis.


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References and acknowledgementsSome fundamental papersAntonucci, R.: Unified models for active galactic nuclei and quasar, 1993, ARA&A, 31, 473ABromm, V. & Loeb, A.: Formation of the first supermassive black holes, 2003, ApJ, 596, 34BConway, J. E. & Murphy, D. W.: Helical jets and the misalignment distribution for core-dominated radio sources, 1993, ApJ, 411, 89CConway, J. E. & Wrobel, J. M. A helical jet in the orthogonally misaligned BL Lacertae object Markarian 501, 1995, ApJ, 439, 98De Paolis et al., F.: Binary black holes in Mkns as sources of gravitational radiation for space based interferometer, 2003, A&A, 410, 741Faber, S. M. et al.: The centres of early-type galaxies with HST. IV. Central parameter relations, 1997, AJ, 114, 1771FFan, MNRAS, 1999, 308, 1032 Hardee. P. E.; Cooper, M. A. & Clarke, D. A.: On jet response to a driving frequency and the jets in 3C 449, 1994, ApJ, 424, 126HKatz, J. I.: A precessing disk in OJ 287, 1997, ApJ, 478, 527Komossa, S.: Observational evidence for supermassive black hole binaries, 2003, AIPC, 686, 161KKomossa, S. et al.: Discovery of a binary active galactic nucleus in the ultraluminous infrared galaxy NGC 6240 using Chandra, 2003, ApJ, 582, 15Lehto, H. & Valtonen, M.: OJ 287 outburst structure and binary black hole model, 1996, ApJ, 460, 207Liu et al., A&A, 1995, 295, 1 Magorrian, J. et al.: The demography of massive dark objects in galaxy centres, 1998, AJ, 115, 2285MRaiteri, C. M.: Optical and radio variability of the BL Lacertae object AO 0235+16: A possible 5-6 year periodicity, 2001, A&A, 377, 396RRieger, F. M. & Mannheim, K.: Implications of a possible 23 day periodicity for binary black hole models in Mkn 501, 2000, A&A, 359, 948RRomero, G. E.; Fan, Jun-Hui & Nuza, S. E.: The binary black hole scenario for the BL Lacertae object AO 0235+16, 2003, ChJAA, 3, 513RSillanpaa, et al.: OJ 287 – Binary pair of supermassive black holes, 1988, ApJ, 325, 628Smith & Nair, 1995, PASP, 107, 863 Valtaoja, E. et al.: Radio Monitoring of OJ 287 and Binary Black Hole Models for Periodic Outbursts; 2000, ApJ, 531, 744Villata, M. & Raiteri, C. M.: Helical jets in blazars. I. The case of MKN 501, 1999, A&A, 347, 30VVillata, M. et al.: A beaming model for the OJ 287 periodic optical outbursts, 1998, MNRAS, 293, L13Volonteri, M. et al., The assembly and merging history of supermassive black holes in hierarchical models of galaxy formation, 2003, ApJ, 582, 559Yu, Q.: Evolution of massive binary black holes, 2002, MNRAS, 331, 935YXu, W. et al.: The bimodal distribution of misalignment angle in powerful extragalactic radio sources, 1994, cers.conf, 7

http://www.gsfc.nasa.govhttp://users.rowan.edu/~polikar/WAVELETS/WTtutorial.html

http://chandra.harvard.edu

http://www-glast.stanford.edu/

Some web references and photo credits


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Last thought

I expect to pass through this world but once; any good thing therefore that I can do, or any kindness that I can show to any fellow creatures, let me do it now; let me not defer or neglect it, for I shall not pass this way again.Ettiene De Grallet

René Hudec, Aimo Sillanpaa, Harry Lehto, Mauri Valtonen, Adam Hill, Filip Munz, Martin Toast Topinka, Ivana Joanne Stoklasová, Libor “Měkká koza“ Švéda, Petr Skalický, Martin “Matesí Péro”

Jelínek, Petr Sobotka

My thanks and acknowledgments for the support with my scientific research and this presentation are passed to the following:

06/10/2004seminar of the astronomuical institute 1 revision of blazars’ nature objects with binary...

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