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New model of unification of active , and the different steps of their formation Melati Rabia

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Melati Rabia. New model of unification of active galaxies, and the different steps of their formation. 2020. ￿hal-02950036￿

HAL Id: hal-02950036 https://hal.archives-ouvertes.fr/hal-02950036 Preprint submitted on 27 Oct 2020

HAL is a multi-disciplinary L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. New model of unification of active galaxies, and the different steps of their formation

MELATI Rabia Department of Physics, Faculty of Exact Sciences and Computer, University of Mostaganem UMAB. Laboratory LEPA University of Sciences and Technology of Oran USTO.

E-mail : [email protected], [email protected]

Abstract: Given the vastness of the , knowing its structure is not easy with the scientific means that we have today. However, these scientific means allowed us to study and know the structure and functioning of the closest objects, such as , planets and some galaxies of the . In this work, we are going to make a comparative study which will allow us to use the knowledge collected on stars, to discover the structure and the functioning of active galaxies.The different images provided by high resolution telescopes and radio telescopes show a great similarity between stars and active galaxies. In this paper, we highlight the different points in common between these two objects. The common points are highlighted by a comparison between: the Radio galaxies and stars of the , and the T Tauri stars, Blasars and the neutron stars, Dust-Obscured Galaxies and the proto stars, "HFLS3 " and the . Basing on the results of this comparison we propose a new model of unification of active galaxies. This new unification depends on the age of the active galaxies and not on their viewing angle. These results also show, the important role of active galaxies in galactic clusters. In a second part of this article, following the obtained results, we present the different stages of formation of active galaxies .

Keywords: ; ; BL Lacertae, DOGs galaxy; Galaxy evolution, galaxy formation.

1 1. INTRODUCTION The classification of galaxies, their distribution in the universe and their motions, provide very important information that helps us to understand extragalactic . In this research, we are interested at the galaxies with active nuclei: , quasars, radio galaxies and other. The current Unified Model, generally accepted by the scientific community, supposes that all galaxies with active nuclei, are in fact the same kind of galaxy, but viewed from different angles (Figure 1).

Fig.1. Model of active galaxies unification according to viewing angle. By studying the images provided by the different space telescopes and the different observatories, and referring to the literature, we present in this paper a new model unification of active galaxies, unification according to their ages and not to their viewing angle. We propose also, a new model of active galaxies formation showing the different phases through which pass an active galaxy from its birth, to the end of its life. This new unified model is based on the comparison of morphologies and characteristics of different objects in the universe, according to two different scales: the intra-galactic scale and the extragalactic scale. This new unification model explains many mysteries of the observed universe and gives answers to several phenomena, to which has not yet found an explanation. 2.PRESENTATION AND COMPARISON OF SOME STRUCTURE OF THE UNIVERSE We start our comparison with a very special case: the comparison between a of the main sequence: our for example which reveals many informations compared to the most distant stars, and the nearest radio galaxy located at the extragalactic space: the giant . M87 reveals more information compared to the most distant elliptical giants. Then we compare T Tauri stars, which are very young stars of intra-galactic space, and the quasars which are very young objects of the extragalactic space, blazars are compared to neutron stars… and so on. After this comparison, we present our new model of unification of active galaxies and the different phases of their formation. 2.1. Presentation of radio galaxies Radio galaxies are active elliptical galaxies, they can reach ten thousand billion solar masses. They are not the dominant type of galaxies in the universe. They are found close to the centers of galaxy clusters, and, dominate the galaxy clusters by their attraction. The images of radio galaxies obtained using high-resolution radio telescopes often show a jet of material ejected directly from the nucleus and

2 ending in lobes. Those lobes are generally ten times greater than the galaxy itself and can sometimes reach several million light years (Esslinger, 2019). Although there are some exceptions, the general characteristics of radio galaxies are: 1- Radio galaxies contain a supermassive black holes with a very strong gravitational field. 2- In their nuclei, the motion of stars is random, unlike spiral galaxies, where all the stars follow the rotational motion of the galaxy. 3- The radio galaxies rotate on themselves. 2.1.1. Comparison between the Sun and the radio galaxy M 87 The different images provided by high resolution telescopes and radio telescopes show a great similarity between the radio galaxy Messier 87 and the Sun. Table 1 shows the different points in common between these two objects. Table 1: Similarities between the Sun and M87 radio galaxy.

THE SUN THE RADIO GALAXY MESSIER 87

1-a) The Sun is a star among the billions of stars 1-b) M87 is one of the elliptical galaxies of the in the , it occupies the center of the cluster which is part of the Virgo super solar system composed of several celestial cluster. The has approximately objects (planets of different sizes, planetary 2000 galaxies (Côté et al., 2004; Baes et al., satellites, a thousands of , , 2010), it is an irregular aggregate of at least three interplanetary dust, etc.), we can therefore say subgroups centered on the three large galaxies that the Sun is at the center of a cluster of M87, M86 and M49. The most important celestial objects. subgroup is centered around M87 (Virgo A). So we conclude that Messier 87 is located at the

center of a subgroup of galaxies.

2-a) The Sun is the brightest object in the 2-b) Messier M87 is the largest and brightest solar system and the most dominant in mass, galaxy in Virgo cluster (Binggeli et al., 1987; alone accounting for about 99.854% of the mass Bird et al., 2010), and in terms of mass, it is a of the Solar System. The Sun is supergiant, dominant member of the cluster (Doherty et compared to planets and celestial objects that al., 2009). Being classified as a galaxy of type surround it. cD, M87 is a supergiant galaxy (Dalia, 2007; Kundu et al., 2001) compared to the other galaxies of its subgroup.

3-a) The Sun is in permanent differential 3-b) Different research teams, work on the rotation, This differential rotation is caused by a kinetics of galaxies, but until now, apart from the convective movement due to the transport of rotation of galaxies around their axes, there are heat. the Sun orbits around the no results that define the exact trajectories of the accompanied by the solar system. A general galaxies. In the reference (Doherty et al., 2009), overview shows that the Sun does not move Michelle Doherty shows that the radio galaxy much relative to the other members of the M87 seems to move very little relative to the solar system. other members of the Virgo cluster and of its subgroup.

3 4-a) The Sun's core, extends from the center to 4-b) The size of an active galaxy's nucleus (as about 0.25 solar radius (Garcia et al., 2007) and Messier 87) is estimated to be a fraction of generates 99% of the nuclear fusion power light-year. The nucleus is tiny in relation to the releasing a great quantity of energy. The core is size of an active galaxy (Esslinger, 2019). In the tiny compared to the size of the sun nuclei of active galaxies a great quantity of energy is produced (Esslinger, 2019; Gebhardt et al., 2011).

5-b) The Sun has a spherical shape and its 5-b) Forming around one sixth of M87's mass, density decreases by going from the nucleus to the stars in this galaxy have a nearly spherically the surface. symmetric distribution. The population density of stars decreases with increasing distance from the nucleus (Wikipedia, 2020a).

6-a) The Sun is surrounded by an aura of hot 6-b) M87 is surrounded by an extended with very low density, named corona. corona with hot, low-density gas (Harris et al., The Sun's corona extends over nearly ten million 1998) M87's galactic envelope extends out to a kilometers (about 70 times the radius of the Sun). radius of about 490000 light years (Wikipedia, During a total solar eclipse ( or by using a 2020a) figure 2 shows Messier 87 surrounded by coronograph), it appears around the black lunar a hot gas. disk as a luminous ring with an irregular rim.

Fig. 2. The false-color image of the galaxy M 87 shows a giant bubble of hot gas around M87. Photo of the Paris Observatory (Techno-Science, 2012).

7-a) Coronal loops are bright, curving 7-b) Observations made by Chandra X-ray structures that appear as arcs and rings above Observatory show loops and rings in the gas the Sun's surface (Figure 3). Coronal loops are that surrounds M87 and emits hot X-ray often rooted in sunspots, arcing between pairs of (Figure 4) (Wikipedia, 2020a). These loops and sunspots with opposite magnetic poles. The rings are generated by pressure waves. The Coronal loops are the results of solar flares. The pressure waves are caused by variations in the variation in the number of solar flares makes it rate at which mater is ejected from the possible to define a solar cycle with an average supermassive . The distribution of period of 11.2 years. This phenomenon is loops suggests that periodic eruptions occur associated with emission of X-rays, radio waves every few million years (Wikipedia, 2020a). and gamma rays.

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Fig.3. Coronal loops of the Sun (Wikistrike, Fig.4. Loops and rings around M87. 2014). Credit: X-ray: NASA/CXC/CfA/W. Forman et al (Chandra, 2016).

8-a) A coronal mass ejection (CME) is a 8-b) M87 has two lobes, their size’s are plasma bubble produced in the solar corona generally ten times larger than the galaxy (Figure 5), its size can reach several tens of the itself and can sometimes reach several million Sun's size. Coronal mass ejections reach light years. They appear connected to the velocities from 20 to 3200 km/s (based galaxy by filaments. The measured velocity of on SOHO/LASCO measurements between 1996 the lobe jet is four to six times the velocity of the and 2003) (Wikipedia, 2020b). light (Wikipedia, 2020a). The plasma bubbles are connected to the Sun The jet is highly collimated. by filaments.

Fig.5. Jet of matter ejected from the sun at very Fig.6. A photograph high speed (Wikipedia, 2020c). showing the jet of matter ejected from M87 galaxy at very high speed (Wikipedia, 2020a)

9-a) The Sun is a source of radiation of all 9-b) Radio galaxy M87 is a strong source of wavelengths, particularly radio waves. It is also multiwavelength radiations, particularly radio a high performance waves (Wikipedia, 2020a). The radio emission source. During the coronal ejections, the atomic of radio galaxies is due to the synchrotron particles go up spiral the . process. Analysis of radio emission of Messier 87 showed that the synchrotron radiation is emitted by relativistic and moving in magnetic fields

10-a) Sunspots and coronal holes are the most 10-b) At the core of M87, seats a supermassive obvious manifestation of the activity of the Sun, black hole (SMBH) (Gebhardt et al., 2011). The they are small dark areas whose diameter varies SMBH ( figure 8) ejects matter emerging from

5 between a few thousand and a hundred thousand the nucleus of Messier 87 in the form of a kilometers and last for a few days to several relativistic jet highly collimated and extending months. Their spectral analysis reveals a very over at least 1.5 kiloparsec (5000 light years) strong magnetic field. The Sun is traversed over (Wikipedia, 2020e) . At the end of the jet, matter its entire surface by magnetic fields. Some of forms a lobe these fields are "closed": they form loops, other The gravitational field of the black hole is very fields are "open": they are directed towards intense (Wikipedia, 2020d). space. In this case a large quantity of matter (plasma) emerging from the solar nucleus is projected beyond the corona by the coronal holes along lines of open magnetic fields and pointing into space ( figure 7). . The jet is in the form of ejections of coronal mass escaping at very high speeds.

Fig.8. The Telescope image of the M87 and its (Ter Missiana, 2019 ; Wikipedia, 2020e) .

Fig.7. Coronal hole observed at the radiotelegraph of Nancy.Paris Observatory/ LESIA (Ludwing Klein, 2013).

11-a) The Sun does not contain a single 11-b) The discovery of the named coronal holes, but several. The size and number HVGC-1 suggests that the core of M87 holds of coronal holes change according to the solar not one but two supermassive black holes cycle. When the Sun reaches solar maximum its (Aguilar, 2014). Several research teams are coronal holes move approaching the Sun’s working on the analysis of gama rays emitted by poles (NASA, 2014). During the solar maximum, active galaxies harboring a supermassive black the number of coronal holes decreases until the hole in order to study the possibility of the magnetic field of the Sun is reversed. At the new existence of other black holes in the same poles, new coronal holes appear, increase in size galaxies. and number, move away from the poles as the Analysis, of data from the Advanced Camera Sun again reaches the minimum of its solar cycle for Surveys, reveals a displacement of the (Etwisle, 2014). At the north and south poles of Supermassive black hole of 6.8 ± 0.8 pc the Sun, there are permanent coronal holes from the galactic center of Messier 87. The displacement is along a position angle of 307◦ ± 17◦ (Batcheldor, 2010).

12-a) During the thermonuclear fusion in the 12-b) The motion of stars in elliptical galaxies Sun's core made up of plasma, Hydrogen atoms is random (figure 9), unlike to the more are fused together to form Helium,. Roughly 3.7 orderly rotational motions of stars in a spiral

6 × 1038 protons (hydrogen nuclei), or galaxy (Wikipedia, 2020a). approximately 619 million tonnes of hydrogen The map of figure 9 indicates random motion of are converted into helium nuclei (614 million the stars. Blue patches represent motion towards tonnes of helium) (Kennewell et al., 2014). The the Earth and red ones away from the Earth, difference (about 4.3 × 106 kg) is converted into while yellow and green are in between the two energy (approximately 3.9 × 1026 ), extremes. according to the equation E = mc2. At this speed, the protons in the Sun's core seem to be moving randomly in the plasma, unlike the planets where the atoms are in their fundamental states.

Fig.9. Stellar velocity map of the central region of M87, showing the motion of stars relative to Earth (Emsellem, 2014; Wikipedia, 2020a).

13-a) The Sun is a near-perfect sphere with a 13-b) In the morphological classification scheme flattening estimated at about 9 millionths for galaxies of Hubble, modified by Gérard de (Godier, 2000). The spherical form of the Sun is Vaucouleurs, M87 is categorized as an E0p shaped by the two opposite forces that maintain it galaxy. M87 appears spherical an it displays no in hydrostatic equilibrium: gravitation force, flattening. (Wikipedia, 2020a). which tends to contract it and cause it to collapse, We can say that The spherical shape of Messier and kinetic pressure force regulated and 87 is also maintained by two opposite forces. The maintained by nuclear fusion reactions which gravitational force (found in all galaxies), and a tends to dilate it. These nuclear fusions take place kinetic pressure force. The gravitational force is in the nucleus which is the densest and hottest compensated by the action of the forces of area, where matter is in the form of plasma. kinetic pressure due to the random motions of Plasma is described in the literature as a “soup” the stars in the nucleus of this galaxy. of extremely active electrons, in which ions or So, we can describe the nucleus of the galaxy neutral molecules “bathe”. M87 in which the stars are in random motion, as Using this description of plasma, we can say that a plasma on an extragalactic scale. the kinetic pressure is maintained by the nuclear fusion which takes place in a plasma, where the motion of protons can seem random.

2.1.2. Interpretation of Table 1 Following all these similarities between the Sun and Messier 87, we can conclude that the Sun and M87 belong to the same family of objects, seen according two different scales "the intra-galactic scale and the extragalactic scale". Thus, we consider the giant M 87 as a star on an extragalactic scale. The Sun being a star of an adult age which has reached the phase of the main sequence in its evolution, we also consider Messier 87 as an active galaxy in adulthood. The idea of comparison on which we based in this article, allows explaining several phenomena

7 concerning Messier M87, to which the scientific community has not yet found an explanation. 1- The energy produced in Messier87's nucleus, comes from the random motion of the stars that we consider as nuclear reactions at extragalactic scale. This random motion creates a force of kinetic pressure which opposes the force of gravitation, and prevents the collapse of M87 on itself. This phenomenon is similar to the random motion of the hydrogen protons in the Sun’s core. This "random" motion of protons is the source of the nuclear reactions. 2- The protuberance loops being the result of a jet of matter along magnetic arcs connecting two sunspots of opposite magnetic polarities, and since the Sun and the galaxy M87 have similar physical and magnetic characteristics, the loops of the galaxy M 87 presupposes the existence of other black holes with opposite magnetic polarities connected by magnetic fields in the form of arcs. In this case, the matter ejected from the nucleus of M87 by the black hole follows curved lines of magnetic field connecting the black hole with other black holes of opposite magnetic polarity. We believe that the existence of black holes of opposite polarities have a significant impact on the lifespan of the AGN galaxies, because through these types of black holes, the active galaxy recovers a large part of the matter ejected by its nucleus. and extends its lifespan. 2.2. Comparison between quasars and T Tauri stars The second comparison concerns the quasars (quasi-stellar radio source): objects of extragalactic space, and the T-Tauri stars: objects of an intra-galactic space. The stars are spread over a large range of sizes and brightness. The size and brightness vary according to the age of each star. The active galaxies are also spread over a large range of sizes and brightness; so, it is evident that their sizes and brightness vary according to their ages. Basing on analysis of provided images by different space telescopes, we note several similarities between two young objects of Universe: quasars and T Tauri stars. The common properties observed between a quasar and a T Tauri star depend on three important factors, including the mass of the black hole and dark spots, the accretion disk and the presence or absence of a jet. Results of comparison are reported in table 2. Table 2: Similarities between T Tauri star and Quasar

T TAURI STAR QUASAR

1-a) The T Tauri stars class belong to the stars 1b) Quasars belong to the family of active family, it includes young stars with feeble mass galaxies. The size of the quasar is related to the (less than 3 solar masses), optically visible and variation of its brightness. The rapidity of this have not yet reached the main sequence (Bertout, brightness variation indicates that the size of 1989). quasar is small. Quasars are the youngest T Tauri stars are among the youngest you can observed objects (Schmidt, 1995). Discovery see, no more than 10 million years old (Wikipedia, surveys have demonstrated that quasar activity 2019). The spectrum of T Tauri stars shows higher was more common in the distant past. The peak lithium abundance than the main sequence stars such of quasar activity was approximately 10 as the Sun. The lithium abundance is characteristic billion years ago. the most distant known quasar of their youth, because lithium is destroyed when the is ULAS J1342+0928 at z = 7.54; light temperature exceeds 2.5 million K. observed from this quasar was emitted when the universe was only 690 million years old (Schmidt, 1995).

8 2-a) The T Tauri stars contain dark spots. The dark 2-b) Quasars contain supermassive black holes spots in the T Tauri star can reach 40% of its having almost the entire mass of the Quasar surface, whereas at its maximum activity, the Sun ranging from millions to billions of times the exhibits spots covering a maximum of 7% of its mass of the Sun (Wikipedia, 2020f). surface (Joncour, 2012).

3-a) The T Tauri stars are often surrounded by 3-b) Quasars are surrounded by an accretion an accretion disk of gas and dust (Figure8) disk formed by matter (Figure 9) (Wikipedia, accumulated during the star formation process. 2020e). The accretion disc is formed by the matter falling into the black hole.

4-a) A large number of T Tauri stars present 4-b) A large number of quasars show bipolar bipolar jets. The jets of matter ejected from the jets of gas expelled from the accretion disk by accretion disk of these very young stars (figure 10) the magnetic field lines (figure 11) (Wikipedia, are confined by a magnetic field (Ferreira, 2001). 2020f). Spectroscopic observations of the Doppler shift, The gas ejected from the accretion disk, reaches indicate that the matters jet travels at speeds of a speed close to that of light (Wikipedia, 2020f). several hundred kilometers per second (Dopita, 1978).

Fig.11. Illustration of the matter disk Fig.10. Illustration of the disk of gas and dust surrounding a quasar and its bipolar jet. surrounding a young T Tauri and its bipolar jet. (Image: © NASA, ESA and J. Olmsted (STScI)) Document T Lombry (.Luxorion, 2017) (Brandon, 2020).

5-a) Herbig-Haro objects are small nebulosities 5-b) Quasars show many properties comparable associated with very young stars as T tauri stars to those of active galaxies: the radiation is non- (figure 12). They are formed when matter ejected by thermal and approximately 10% are observed to these young stars collides with surrounding clouds also have jets and lobes like those of radio of gas and dust, at speeds of several hundred galaxies (Wikipedia, 2020f) as show in figure 13. kilometers per second (Wikipedia, 2019).

Fig.12.The Herbig-Haro HH47 object as seen by the Hubble Space Telescope. The scale bar represents Fig.13. A double-lobed radio source quasar 1000 AU. 3C334 (Image of VLA 6 cm) NRAO 1996.

9 The radiation emitted by Herbig-Haro objects is due The lobes radio carry a significant amounts of to shock waves caused by the collision with the energy in the form of particles moving at . relativistic speeds.

6-a) Like all stars, T Tauri stars rotate on themselves 6-b) Like all active galaxies, quasars rotate on and they are know by sudden and unpredictable them-self and they are known by the variations in their . extraordinary variability in their brightness. Their brightness can vary significantly in a day,

or even in a few hours (Esslinger, 2019).

7-a) According to the currently accepted and 7-b) Several observations made by different confirmed scenario by observations, stars form in researchers and different teams of astronomers groups in molecular cloud of gas and dust as show confirm that quasars form large groups (LQG), in figure 14 (Evgeny, 2007). The formation of stars they are a large astronomical structures. is generally schematized by three main modes: The large groups of quasars differ in their 1. Sporadic training in small systems, from one to a number of quasars, in some LQG the number is few stars; less than 10, such as: Webster LQG (5 quasars) 2. A formation in groups of stars of ten to a hundred (Webster, 1981; Clowes et al., 2013) and Tesch – members, as in the Taurus. Engels LQG (7 quasars) discovered respectively 3. A cluster formation, in giant molecular clouds, in 1982 and 2000, where a large number of stars are born in a dense Other LQLs have a number greater than 10, such and gravitationally linked system, as in Orion B. as: Clowes–Campusano LQG (34 quasars) Using the wavelength of the two powerful giant (Clowes et al., 2012; Clowes et al., 2013), radio telescopes VLA and ALMA, astronomers were Newman LQG (21 quasars) and others. able to look through the clouds of dust and take a The Largest Quasar Group is the Huge-LQG, it picture of some 328 stellar embryos. Astronomers consists of 73 quasars and extends about 1.6 used electromagnetic waves to draw the shapes of billion light-years away in most directions, and 4 these celestial objects. Then they added false colors billion light years in its greatest width (Clowes et (Delacharlery, 2020). The yellow dots are the al., 2013), (figure 15). locations of the "young stars".

Fig.15. The large group of quasars (LQG) (Clowes et al., 2013). Fig.14. Young stars grouped in a molecular cloud. - LQG is clearly seen as a long chain indicated by ALMA (ESO / NAOJ / NRAO), J. Tobin; NRAO / black circles. Red crosses mark the positions of AUI / NSF, S. Dagnello. (Delacharlery, 2020). the quasars in a smaller group.

10 2.2.1. Interpretation of Table 2 Table 2 show that, Quasars and T Tauri stars also have the same morphology and present the same characteristics. The physical and magnetic phenomena observed in T-Tauri stars are also observed in quasars. So we deduce that T Tauri stars and quasars are objects of the same family, according two different scales: intra-galactic scale and extragalactic scale. The results obtained following this comparison allow us to give explanations for several phenomena that are still enigmatic. 1- Quasars are very young galaxies with active nuclei, they have not yet reached adulthood, so: Quasars are active galaxies at the beginning of their formation cycle. 2- Most quasars do not form in isolation, but form in groups in a cluster of stars and clouds of dust that we name: “Galactic nurseries”, like the T Tauri stars which form in groups in molecular clouds. These nurseries are the large quasar groups (LQG) confirmed by observations 3- On the extragalactic scale, if the quasar follows the same life cycle as the T-Tauri star, the quasar will be transformed during its life cycle into a radio galaxy. 4- A supermassive black holes having almost all of the mass of the quasar confirms its young age, just like the T Tauri star whose surface is well occupied by dark spots 2.3. Comparisons between BL Lacertae and neutron stars The third category of active galaxies is the category of BL Lacertae (Blazing quasi-stellar radio source). According to the model of unification of active galaxies, blazars (BL Lacertae) are galaxies with active nuclei. Their particular aspect comes from the fact that the Earth is just in the axis of the jets and radio lobes. By studying Blazars and neutron stars, we notice a shocking resemblance between these two objects of universe . Basing on their characteristics and their functioning, we will make a comparison between the that we consider as an object of the extragalactic space and a , object of intra- galactic space. The results of this comparison are presented in Table 3. Table 3: Similarities between a Neutron star and a Blazar

NEUTRON STAR BLAZAR

1-a) Neutron stars are some of the densest 1-b) In visible-wavelength images, most blazars manifestations of massive objects in the universe. (BL Lacertae) appear compact and pointlike, (Lattimer, 2004). suggesting that they are small active galaxies. Neutron stars have a radius on the order of 10 Being a highly variable bright source and small, kilometres and a mass of about 1.4 solar masses the Blazar was originally thought to be an ( Seeds et al, 2009). They are the smallest and irregular variable star. densest stars known to exist. The Blazar was discovered as a radio source in Neutron stars are detected by their 1983, and has since been observed across the electromagnetic radiation and are generally entire . observed to pulse radio waves and other electromagnetic radiation.

11 2-a) The neutron stars have an extremely high 2-b) The blazars are highly variable, their rotation speed and have rotation periods from brightness can vary by a factor of one hundred about 1.4 ms to 30 s. The fastest-spinning over very short time (about a few weeks). This neutron star is PSR J1748-2446ad, rotating at a variability is probably due to very rapid rate of 716 times a second (Hessels et al., 2006). pulsations, therefore to an extremely high speed rotation and a very small size (Xie, 2001; Bauer et al., 2009). 3-a) The jet of matter emitted from the magnetic 3-b) The Blazar emits a relativistic jet which poles of the neutron star scan two thin areas of points in the general direction of the Earth the sky (figure 16). One of the two jets, is pointed (figure175). The trajectory of the jet in the direction of the Earth. The jet's path corresponds to our line of sight, which corresponds with our line of sight, which explains the rapid variability and the compact explains its rapid variability. characteristics of the Blazar.

Fig.16. Artist's impression of a neutron star Juric.P/Depositphotos (Lavars, 2019). Fig.17. Artist's impression of a blazer (Wikipedia, 2020g). The jets of the two poles move at almost the . The jet of matter travels toward the observer at nearly the speed of light (Wikipedia, 2020g).

4-a) Neutron stars have strong magnetic 4-b) The jet of Blazar is collimated by an fields. The magnetic field strength on the surface intense magnetic fields combined to a powerful of neutron stars has been estimated at least to winds from the accretion disk and toroid. have the range of 104 to 1011 tesla (Reisenegger, (Wikipedia, 2020g). 2016).

5-a) A neutron star is the compact residue 5-b) The link between blazars and radio galaxies resulting from the of the was confirmed by high resolution observations, core of a massive star when it has exhausted its which reveal that blazars are located at the nuclear fuel. This collapse is accompanied by an center of elliptical galaxies (Megan, 2000) explosion of the outer layers of the star, which Figure 19 show a Blazar at the center of the host are completely dislocated (phenomenon called galaxy, its close companions are visible. ). The result give a neutron star at the center of a supernova (figure 18).

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Fig.18. Neutron star at the center of a supernova Fig.19. The BL Lacertae object: 0323 + 022 (Crane, 2018). (z = 0.147) view taken by ESO NTT (filter R) (Wikipedia, 2020h).

2.3.1. Interpretation of Table 3 Following this comparison based on observations, we notice a great similarity between a neutron star, and a Blazar, except that the two objects belong to two different spaces: the intra-galactic space and the extragalactic space. Therefore we conclude that: 1- The variability of the blazars brightness is due to their very small sizes and their very high speed rotation. 2- Why is the blazar located at the center of a host galaxy? This question has not yet found an answer. We propose an answer to this question by using results of the three Tables and the following hypotheses, If we assume that stars and active galaxies follow the same steps to reach the end of their life, the mystery of the blazar at the center of a host galaxy will be explained. Only to give an answer to this question, it is imperative to firstly make a comparison between the galaxy HFLS3 and a red giant. 2.3.2. Comparison between the HFLS3 galaxy and a red giant HFLS3 is a massive galaxy located at z = 6.34. Its discovery was announced on 18 April 2013. HFLS3 was discovered thanks to ALMA telescope network and the Herschel Space Observatory. It dates back 12.8 billion years, so it is a very old galaxy. HFLS3 makes new stars at more than two thousand times more rapidly than our own Milky Way ( Riechers et al., 2013). This particular galaxy HFLS3 caught the attention of investigators because of its red color ( Riechers et al., 2013). Let’s now make a comparison between the galaxy HFLS3 and that of a massive star arriving at the end of its life. At an intra-galactic scale, when a massive star leaves the main sequence, it starts new fusion reactions to produce other chemical elements: silicon, magnesium, neon, oxygen, carbon, helium, hydrogen and iron. So, we can say that a massive star approaching the end of its life, becomes very fecund in chemical elements, its volume increases more and more, its color becomes red, and it ends up exploding in supernovae, its inert iron core collapses into an extremely dense neutron star or a black hole. Assuming that the same scenario of the stars formation is repeated for the active galaxies formation: When an active galaxy is approaching the end of its life, it becomes very fecund in stars, its volume increases dramatically and becomes a massive active galaxy, its color becomes red, so, the active galaxy is transformed in a red giant galaxy such as the giant HFLS3. This transformation causes an imbalance in the forces that maintain its static equilibrium. When the force of gravity becomes

13 more important than the kinetic pressure force that maintains its equilibrium, its nucleus implodes, and its outer layers are dislocated by the process. The residue left by the implosion of the nucleus is an extremely compact object, which can be a blazar detectable by its highly variable brightness. This collapse is accompanied by an explosion of the outer layers of the active galaxy, which are completely dislocated. The Blazar will therefore be surrounded by a band of dust and stars, showing the Blazar at the center of a host galaxy. 2.3.3. Comparison result After this comparison, we conclude that the blazar is not located at the center of a host galaxy, but at the center of the residues left by an active galaxy at the end of its life, we can say "at the center of a supernova in extragalactic scale". So we suppose that: The blazar and neutron stars are objects of the same family, according two respectively different scales: extragalactic scale and intra- galactic scale. 2.4. Comparison between a Hot Dust-Obscured Galaxy (DOGs) and a proto-star Hot Dust-Obscured Galaxy (DOGs ) is a new type of galaxy detected in August, 2007 by using NASA Swift and JAXA Suzaku. This new type of active galaxy that we consider as an object of the extragalactic space also has its similar at the intra galactic space: the proto-star. So, it will be interesting to compare this two Universe objects In the Hot Dust-Obscured Galaxy, the disk and torus surrounding the black hole are so deeply obscured by gas and dust that no visible light escapes, making them very difficult to detect. Gas and dust form a cocoon around the DOGs (Figure 20 ). DOGs are very faint in the optical, but are bright in the IR. The most luminous Hot DOGs have star formation rates (500–1000 solar masses per year, or 13-14 more) and LIR~10 L☉ (Bussmann et al 2012., Weedman et al., 2012).

Fig.20. Artist's impression of the newly discovered AGN surrounded by a shell of gas and dust. Credit: Aurore Simonnet, Sonoma State University (Naeye, 2007). Hot Dogs galaxies, may play an important role in the evolution of massive galaxies (Bussmann et al, 2012; Grossmanet al, 2012). At the intra-galactic scale, the description of this new type of galaxy, is familiar to us! it is the description of a proto-star. A protostar is a very young star that is still gathering mass from its molecular cloud. The protostellar phase is the earliest one in the process of . The proto-star is surrounded by its cocoon which absorbs completely visible radiation, only the infrared radiation and X wavelengths manage to escape in a small proportion.

14 2.4.1. Comparison result The proto-stars and Hot Dust-Obscured Galaxies (DOGs) have the same morphology and present several points in common, so they may represent the same object family, according two different scales: intra-galactic scale and extragalactic scale. Thus, we can say that the Dust-Obscured galaxy is the embryo that gives birth to an active galaxy. 3. UNIFICATION OF ACTIVE GALAXIES ACCORDING TO THEIR AGES Following this study, we conclude that all active galaxies are classified in a table in which DOGs galaxies occupy one extremity and the blazars occupy the other extremity. DOGs galaxies are active galaxies at the early of their life cycles, while blazars, are active galaxies at the end of their life cycles. Between Hot DOGs galaxies, and blasars, seat the entire population of AGN at intermediate age (quasars , radio galaxy… ) (Figure 21).

Fig.21. The evolution stapes of an active galaxy.

We also conclude that: 1) The quasars are galaxies with active nuclei, and not nuclei of actives galaxies. 2) DOGs galaxy, Quasar, Radio galaxy, Blasar and other AGN represent the same type of active galaxies seen at different ages. 4. NEW FORMATION AND EVOLUTION MODEL OF THE ACTIVE GALAXIES The standard model of galaxy formation is based on almost spherical gas accretion and collisions between older galaxies. This model has recently been challenged by new observations made by giant telescopes. In the new theory, most galaxies grow by continuous accretion of gas from cold currents, rather than collisions between satellite galaxies (Dekel, 2009). In this article, we present a new model of the active galaxies formation. This new model take in consideration all results of the comparisons presented in this paper . The four types of galaxies in the extragalactic space: Hot DOGs Galaxy , quasar, radio galaxy, blazar, have respectively, their similar in intra-galactic space: they are, the proto-star, T Tauri star, star of the main sequence , and the neutron star. So, we can conclude that the active galaxies and stars belong to the same object family according two different scales, Therefore it follows that the same process formation of the stars repeats itself at the extragalactic scale to form active galaxies. Basing on this comparative study, we propose a new model of active galaxies formation: The active galaxies are born in groups (just like stars), and the discovery of large clusters (LQG) of quasars confirms this hypothesis. The active galaxies are born in clusters of stars and clouds of dust and gas (Dekel, 2009) having equal or greater dimensions than the cluster Huge-LQG2 and able to form tens (may be hundreds or more) of active galaxies. In this new model we present the different phases of evolution of an active galaxy from its birth to the end of its life.

15 4.1. First phase: The Dust-Obscured Galaxies The formation of active galaxies is done in groups, following a fragmentation of a gigantic cluster of dust, gas and stars. Inside the gigantic cluster whose balance has just been broken, the fragments begin to contract under the gravitational effect. As the compression increases, the density increases, the temperature increases, and each fragment becomes more and more opaque and prevents the radiation from eliminating excess energy. A proto-active galaxy (proto-AGN) is born and it radiates in the infrared: it is a Hot DOGs galaxy difficult to detect. 4.2. 2nd phase: Quasars at bipolar jets The matter of the cocoon forms a disk around the proto-AGN, the disk is denser than the surrounding environment. Due to the compression of the cloud of the proto-AGN, the temperature rises again and a prodigious energy release follows. Much of the surrounding cloud of gas and dust ends up being ejected by strong winds generated by the proto-AGN. The jets appear where the disk of gas and dust is thin: the poles. Thereby, ejecting is bipolar. In the center; an active galaxy is born and grows by accretion of surrounding matters. An accretion disk accompanies this galaxy: A quasar is born. 4.3. 3rd phase: The Radio Galaxy Accretion is accompanied by the ejection of a significant part of matter falling on the galaxy; the galaxy grows by exhausting the surrounding matter. When the accretion disk disappears, the quasar turns into a radio galaxy: an active galaxy of adulthood. At this stage of evolution, the temperature of the nucleus is sufficient to provide energy for the stars. This energy will push them to move randomly in the nucleus. The random motion of the stars, creates a kinetic pressure force which opposes the gravitational force and maintain the radio galaxy in static equilibrium. We can even say "hydrostatic equilibrium" because the medium in which the stars move randomly inside the nucleus can be compared to a plasma on an extragalactic scale (figure 22).

Fig.22. Opposing forces that maintain the radio galaxy in static equilibrium.

4.4. 4th phase: The blazar Approaching the end of its life, the radio galaxy grows increasingly by activating the star formation process. Its star formation rate, increases incredibly (Process similar to a galaxy HLFS3). The radio galaxy produces new stars at such a rate that their own radiation disperses matter of its outer layers. The force that opposes to the force of gravity disappears, so, the nucleus of the radio galaxy collapses on itself under the gravitational effect and its density increases dramatically, hence the formation of a blazar.

16 The scattered matter surrounds the blasar and we obtain an object similar to a supernova at extragalactic scale. This supernovae at extragalactic scale makes us always see the blazar at the center of a giant galaxy ( a host galaxy). 5. CONCLUSION Basing on the approach presented in this paper that defines the active galaxies as stars at a larger scale, several mysteries of the Universe find their explanations: 1- The supermassive black holes in the nuclei of active galaxies are a stellar spots reproduced at a larger scale (extragalactic scale). To better understand the usefulness and role of black holes, it just simply to study the stellar spots, especially, sunspots. 2- The loops of the galaxy M 87 presuppose the existence of other black holes of opposite magnetic polarities. 3- The presence of rings, loops and radio lobes in radio galaxies, explain that the radio galaxies undergo eruptions and prominences at an extragalactic scale similar to those that occur to intra- galactic scale in adulthood stars (such as the Sun). 4- The energy produced in the nuclei of active galaxies comes from the random motion of the stars that we consider as thermonuclear fusions at an extragalactic scale. 5- The radio galaxy is a galaxy of adulthood, which has reached its static equilibrium maintained by the force of gravitation and the force of kinetic pressure. The force of gravity tends to contract the radio galaxy and increase its temperature, while the pressing force resulting from the random motion of stars tends to increase its volume and decrease its temperature. 6- The fact that radio-galaxies are considered like stars on the extragalactic scale, explains their presence in the center of subgroups of galaxies just like stars which are in the center of their planetary systems. 7-The very young age of quasars explains the presence of supermassive black holes occupying a very large area of the quasar, like the stellar spots that occupy a large area in young T Tauri stars. 8- The approach presented in this article explains also, the mystery of the grouping of quasars. Because quasars are considered as "young stars at a larger scale ", and because stars are born in groups, it is obvious that quasars are born also in groups. ACKNOWLEDGEMENTS I thank Professor LOUNIS Mourad for his invaluable help.

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