Spectral observations of Markaryan galaxies. II

Conclusions Since there is sufficiently detailed information on the observed galaxies listed in the notes to Table 1, we briefly summarize the main results.From the observations of 94 objects, emission lines are discovered in 64; in one, Markaryan 396, hydrogen absorption lines are observed (this is a white dwarf, probably type DA, and possibly a weak radio source [23]). In the red region there are no lines detected in the objects Markaryan 422(3), 425(3), 431(4), 433(3), 616(3), 621(5), 643(4), 655(5), 656(4), and 658(3); the number of spectrograms is indicated in parentheses; it is possible that Markaryan 643 is a galactic cluster.The objects Markaryan 595, 609, 622, 688, 699, and 700 have broad, hydrogen emission lines and can be attributed to the Seyfert class of galaxies. Markaryan 609, 622, and 699, plus, probably, Markaryan 423, possess moderate Seyfert characteristics. Furthermore, in Markaryan 414, 584, 612, 617, 646, 670, 684, and 693 broad emission lines are observed or suspected. Markaryan 586 is probably similar to a QSO. Further observations are advisable for all these objects.In conclusion, the authors express their gratitude to A. L. Shcherbanovskii for help in the treatment of the spectrograms on the M-222 computer.Institute of Astrophysics, Academy of Sciences of the Kazakh SSR. Special Astrophysical Observatory, Academy of Sciences of the USSR. Translated from Astrofizika, Vol. 12, No. 4, pp. 665–682, October–December, 1976.     

Parametric relations of H II galaxies

The integrated H luminosities of giant H II regions and of H II galaxies can be predicted with accuracy comparable to the observational errors from the velocity widths of their emissionline profiles. In addition, giant H II regions also present a relation between linear size and their emission-line width. Based on the similarity of these relations with those expected for virialized systems, Terlevich and Melnick interpreted the observedsupersonic motions as due to the gravitational potential of a complex of gas and stars.We show that H II galaxies also present a relation between linear size and their emission-line width, which supports the gravitating model. We also show that the scatter in the luminosity-line width relation for H II galaxies seems to be correlated with linear size and compare the results with the fundamental plane for elliptical galaxies from Dressleret al. (1987).     

On the relation between radius,luminosity, surface brightness,and surface density in elliptical galaxies

We have analyzed luminosity profiles of E galaxies studied by Strom and Strom in six clusters of galaxies. We have found a relationship between radius, luminosity, and surface brightness for galaxies in each of the clusters. A dependence of the zero point of the relation with the local projected density of galaxies is likewise found:r _{e proj} ^–0.14 L ^0.445 I _e ^–0.413 . This relationship implies (i) that there is not a universal luminosity profile for elliptical galaxies, (ii) the environmental variation of radius is larger than that produced by mergers of galaxies, (iii) distance to a galaxy can be estimated from apparent magnitude, surface brightness, angular size, and apparent local projected density of galaxies.     

V-R diagram for spiral galaxies. New insights into the hubble sequence

We examine the relation between the global parameters of spiral galaxies and their morphological type. We have represented the rotational velocityV at a radius of 25 mag arc sec^–2 against this radiusR for a sample of 56 galaxies. Different types of galaxies appear separated on this diagram. We have plotted above theV-R diagram isolines of total mass, angular momentum and mean surface density for isolated galaxies with circular motion in centrifugal equilibrium showing: (1) That the parameter that represents the morphological type is the mean surface density or its observational parameterV ²/R. (2) From aV-R diagram we can easily see what kinds of correlations we expect to find between the global properties of galaxies and their morphological type. (3) For every morphological type of galaxies there is a critical mass above which there is a change in its dynamical behaviour. Finally, consideringV ²/R as representative of the morphological type, we can deduce theoretically the empirical Tully-Fisher relation and the dependence of the slope and the zero point on the morphological type. The separation in logV that we expect to find for different types of galaxies for a constant luminosity is the same order as the experimental errors in the determination of logV. This explains the tight power-law relationship observed between this and the luminosity.     

The evolution of dwarf galaxies

We propose an evolutionary model for dwarf galaxies in which initially metal-poor gas-rich dwarf irregular (dI) galaxies evolve through bursting Blue Compact Dwarf (BCD) stages and eventually fade from the BCD phase to become dwarf ellipticals (dE). During the bursting phase the surface brightness of the galaxy increases rapidly due to enhanced OB star formation. The source of fuel for the intermittent bursts of star formation is assumed to be primordial gas which continues to collapse onto the already formed central structure. The dE galaxies form as a result of eventual gas depletion through star formation.With this proposed dIBCDdE evolutionary sequence we can explain the similar photometric structure of the different dwarf types and the differences in their star formation rates, surface brightnesses,Hi contents and metallicities. A final central BCD burst can account for the nucleation in brighter dEs and their residual star formation, while earlier more widespread star formation bursts would fade to give an irregular dI. Inflow of gas may allow dEs to be less flattened than dIs.Using galaxy fading and metallicity models we can reproduce the observed number ratiosN(dI)N(BCD) andN(dI)N(dE) and also the observed metallicity magnitude relation of local dwarf spheroidal galaxies.     

Red post-starburst galaxies

Observations of nearby star-forming regions suggest that the initial mass function is deficient in low-mass stars when the ambient star formation rate is high. We investigate the consequences of a truncated initial mass function on the photometric evolution of starburst galaxies using new models of stellar population synthesis. A major prediction with respect to the case of a standard initial mass function is that the spectra of the galaxies become unusually red when the turnoff mass reaches the cutoff of the initial mass function. This red phase can last for more than 10⁹ yr if the lower cutoff is less than 2M . The amplitude of the reddening depends only weakly on the lower cutoff but increases with the fraction of the galaxy mass involved in the starburst. Such unusually red (V - K > 3.5) post-starburst galaxies can be distinguished from galaxies reddened by dust or with abnormally high metallicities by their unusually strong 4000 Å break and the presence of stellar absorption features typical of late-type giants.     

Flat Galaxies of the RFGC Catalog Detected in the HIPASS Survey

Data from the H I Parkes All-Sky Survey (HIPASS) of the southern sky in the neutral hydrogen line are used to determine the radial velocities and widths of the H I line for flat spiral galaxies of the Revised Flat-Galaxy Catalog (RFGC) seen edge-on. The sample of 103 flat galaxies detected in HIPASS is characterized by a median radial velocity of +2037 km/sec and a median width of the H I line at the level of 50% of maximum of 242 km/sec. For RFGC galaxies the 50% detection level in HIPASS corresponds to an apparent magnitude B _t = 14 ^m .5 or an angular diameter a = 2.9. The relative number of detected galaxies increases from 2% for the morphological types Sbc and Sc to 41% for the type Sm. The median value of the ratio of hydrogen mass to total mass for RFGC galaxies is 0.079. With allowance for the average internal extinction for edge-on galaxies, <B _t< = 0 ^m .75, the median ratio of hydrogen mass to luminosity, M _{H I}/L _B = 0.74 M /L , is typical for late-type spirals. Because of its small depth, HIPASS reveals only a few RFGC galaxies with previously unknown velocities and line widths.     

Far infrared emission from galaxies

Until recently far infrared (FIR) observations of galaxies were limited to about a dozen bright and/or active galaxies. New photometric data has become available from Infrared Astronomical Satellite (IRAS) on 33 galaxies (most of them faint) from IRAS Circular Nos. 1, 2, and 3 The FIR spectra of these galaxies are similar. The far infrared fluxF _FIR in the wavelength interval 9–118 m of the brighter galaxies is seen to be correlated with the integrated optical magnitudeB _T ⁰ . The 12 and 25 m fluxes of these galaxies exhibit the same dependence onB _T ⁰ as the 10 and 21 m fluxes from Seyferts and other emission-line galaxies. This suggests that the galaxies detected by IRAS are some type of active galaxies in accord with the high percentage of these galaxies predicted by Lock and Rowan-Robinson (1983).     

Dark matter particles and the flat rotation curves of spiral galaxies

It is shown that a gas of massive bosonic particles (m 60 eV), e.g. Higgs particles, surrounding disk galaxies is able to generate the flat rotation curves of spiral galaxies without internal difficulties with physical principles. We have analyzed 36 galaxies and find good agreement with the empirical data.     

Redshift distribution in extragalactic objects and evolution of galaxies

In order to see whether the study of redshift distribution in different classes of extragalactic objects, suspected of belonging to different phases in the evolutionary sequence of galaxies, helps in arriving at a possible picture of the evolutionary sequence of galaxies, histograms have been plotted between the number and the redshift for each of the five classes of extragalactic objects, namely, the QSOs, N-galaxies, Seyfert galaxies, radio galaxies and normal galaxies. It is found that: (i) the highest peaks in the five histograms occur at distinctly different redshifts in the order (Z _peak)_QSOs>(Z _peak)_N-galaxies>(Z _peak)_{Seyfert galaxies}>(Z _peak)_{radio galaxies}> (Z _peak)_{normal galaxies} and (ii) sufficient overlap occurs in the redshift ranges of (a) QSOs and N-galaxies, (b) N-galaxies and Seyfert galaxies, (c) Seyfert galaxies and radio galaxies and (d) radio galaxies and normal galaxies. These facts suggest that the extragalactic objects might be evolving in the sequence: QSOsN-galaxiesSeyfert galaxiesradio galaxiesnormal galaxies. Other independent evidences in support of such an evolutionary sequence have been given. Finally, various aspects of the problem associated with the picture of the evolutionary sequence of galaxies have been critically examined.     

The activity of the nuclei of spiral galaxies and IR-emission

It is shown that the brightness of the spiral galactic nuclei at 10 depends on the Byurakan type of galaxies: the brightness is higher in the case of galaxies of types 5, 2s, 4, and 2 with optical signs of activity in comparison with galaxies of types 3 and 1 without optical signs of activity. The noted difference is larger when nonstellar emission at 10 is considered. The obtained results confirm conclusions made earlier on the activity of the nuclei of galaxies of types 5, 2s, 4, and 2.     

Quasi-stellar objects and evolution of galaxies

In view of the striking similarities between Quasi-Stellar Objects on the one hand and the nuclei of N galaxies, Seyfert galaxies, radio galaxies and normal galaxies on the other, the possibility that QSOs might belong to an early phase in the evolutionary sequence of galaxies is explored. In this connection, considering the fact that nebulosities have been detected around five QSOs, the implications of the hypothesis that a QSO consists of a bright central object embedded in an extended nebulosity have been examined. In particular, the ratio a between the intensity of the bright central object and that of the surrounding nebulosity in the visual band of wavelengths has been calculated by the colour-given method for a sample of 81 QSOs with emission redshiftz0.76. This ratio a has been used to calculate the apparent visual magnitudem(V) and the absolute visual magnitudeM(V) of the bright central object (Nu) as well as that of the surounding nebulosity (Neb) of the QSOs in the sample and a criterion has been proposed as to the detectability of the surrounding nebulosities. Similar calculations have been made for N galaxies, Seyfert galaxies and normal galaxies. It is found that the values of log a, M(V) _Nu and M(V) _Neb for the four classes of extragalactic objects show a definite trend and suggest an evolutionary sequence: QSOsN galaxiesSeyfert galaxiesnormal galaxies.     

Megamaser galaxies

An analysis of a sample of OH megamaser galaxies is presented. It is shown that the dependence of L_OH on L_FIR (far infrared) is not quadratic, as previously assumed, but closer to linear. In megamaser galaxies, L_C (radio continuum) L_FIR1. Analysis of the data also shows that as the OH emission line width decreases, the absolute values of the pumping efficiency and maser amplification coefficient increase. The radio luminosity of the central component in these galaxies increases with a decrease in the ratio L_FIR/L_C, whereas the FIR luminosity remains constant. These results will, in all probability, force a reexamination of the questions of pumping and maser emission mechanisms in megamaser galaxies.Translated fromAstrofizika, Vol. 39, No. 3, pp. 417–429, July–September, 1996.     

Rotation Curves of Galaxies in Various Space Environments

A sample of giant Sb-Sc spiral galaxies for which there are highly accurate and extended rotation curves was considered. Having divided the galaxies into three groups as a function of the overall spatial density of luminosity (mass) within 0.5 Mpc ( _L ), we investigated the characteristics of the rotation curves as functions of _L . It turned out that for such massive galaxies, the shape of the rotation curve (the logarithmic gradient) and the Tully-Fisher relation do not depend on the overall space environment. The only difference is that the rotation curves of galaxies in regions with high _L can be traced out to smaller relative distances from the nucleus, on the average. This may be related to destruction of the outer regions of their gaseous disks in gravitational interaction with surrounding galaxies.     

The Morphologies of Dwarf Markarian Galaxies

The morphologies of the 96 dwarf (M(B) -17^m) galaxies in the Markarian catalog are determined from the digitized Schmidt plates obtained for the construction of the Hubble Space Telescope Guide Star Catalog. The fraction of double nucleus galaxies within the dwarf Markarian galaxies is determined to be twice that found for all galaxies in the Markarian catalog. In addition to the 12 previously known cases, four definite and two probable galaxies with double nuclei are identified. The fraction of dwarf Markarian galaxies with bright star forming regions is found to be twice that of Virgo cluster dwarf galaxies. No Elliptical galaxies are found in the sample. Galaxies with blue compact dwarf and S0 morphologies are more often found to contain unresolved regions of UV excess emission. Dwarf Markarian galaxies with different morphological structures and spectral classes are found to have similar FIR properties.     

Do morphological properties of interacting galaxies indicate that the latter are topological abelian higgs vorto-sources (vorto-sinks)?

We propose an Abelian Higgs model for spiral galaxies in which the latter are treated as topologically stable magneticvorto-sources (-sinks). The model is characterized by the minimum coupling between the electromagnetic vector potential and a scalar, complex-valued Higgs field that results - for an idealized cylindrically symmetric case - in a perpendicular to the galaxy's plane distribution of magnetic field strength whose total flux is a discrete-valued quantity - aninteger multiple of the elementary flux unit. Adopting the hypothesis that spiral arms trace the curves of a constant phase of the Higgs field we demonstrate that, for an almost-everywhere divergence-free vector potential, the arms acquire the observationally well-established form of logarithmic spirals whose woundness is here of an electromagnetic origin in the sense that it depends on the ratio between the specific volume-divergence of a galaxy and its total magnetic flux. The hypothesis further implies that the number of spiral arms is justtwice as that of magnetic flux quanta a galaxy possesses; the observed preponderance of two-armed spirals then simply reflects the fact that most galaxies carry single flux quantum which is energetically favourable for the vorto-sources (-sinks) whose disk-to-bulge radius ratio > 1. The latter property also leads to the process of galaxyfragmentation in the sense that a galaxy endowed withp magnetic flux quanta should fission into the topologically equivalent configuration consisting ofp singly-quantized galaxies.A unique possibility to test our model is provided by physically paired galaxies. Considering the simplest configuration consisting of spirals lying in the same plane and having equal in magnitude fluxes and volume-divergences we distinguish four topologically different distributions of the Higgs field phase which fairly well capture observed morphologies exhibited by double galaxies; we find, in particular, that of most frequent occurrence seem to be couples with anti-parallel orientation of magnetic field.Finally, we address the question of the periodicity in the distribution of galaxy redshifts and show that a discrete-valuedness of themass of spiral galaxies resulting from our model may serve as a starting point to solve this puzzling effect.     

Gas content of infrared luminous markarian galaxies

The atomic and molecular hydrogen gas properties of a complete sample of Markarian galaxies with flux density at 60 µm higher than 1.95 Jy are presented. We present the improved far-infrared luminosity function of Markarian galaxies; and its comparison with other samples. We find that 40% of the bright IRAS galaxies of far-infrared luminosity higher than 10^10.5 L are Markarian galaxies. There is an absence of correlation between HI content of Markarian galaxies and current star formation activity, implying that star formation in these systems has complex structure and it is not a simple function of the HI content. On the contrary, the H₂ content of Markarian galaxies is well correlated with star formation activity. It is argued that tight correlation between HI and H₂ contents is a consequence of transformation of atomic hydrogen into molecular.Published in Astrofizika, Vol. 38, No. 4, pp. 636–644, October–December, 1995.     

A classification of galactic collisions for galaxies of unequal dimensions

The earlier work on classification of galactic collisions for identical galaxies is extended to the situations where the two colliding galaxies differ in mass and dimension. We consider collisions between galaxies of masses 10⁷, 10⁹, 10¹¹ and 10¹³ M and let their radii be 0.1, 1, 10 and 100 kpc, respectively. The density distribution in both galaxies is represented by that of a polytrope of indexn=4. The type of collision is determined for head-on collisions for initial relative velocities 500, 1000, 2000 and 3000 km s^–1. The corresponding final velocities are also indicated.     

Radio AGNs among Luminous Infrared Galaxies

An analysis of radio and FIR emission in over 1500IRAS selected galaxies produces a good linear correlationbetween radio and FIR luminosity, indicating that star formationin normal field galaxies dominates the infrared luminosityin the local volume. Galaxies with clear radio-excess (definedas having at least5 times larger radio flux over expected from FIR) are identified as hosting a radio AGN, and they account for onlyabout 1% of the whole sample. This fraction increases to 10% among themore luminous galaxies with L _1.4GHz 10²³ W Hz^-1 (equivalently L _60m 10¹¹ L), however. The characteristic mid-IR excess of a Seyfert nucleus is ubiquitously present amongthe radio-excess objects, suggesting that mid-IR excess isa robust tracer of an AGN despite the high mid-IR opacity.We conclude that about 30% of the luminous infrared galaxies(L _60m 10¹¹ L) host an AGN based on themid-IR excess, and about 40% of the mid-IR excess AGNs alsohost a radio AGN. A VLA imaging survey of a distance limited sample of IR luminousgalaxies has revealed the presence of 100 kpc scale giant radioplumes in 3 out of 9 cases (Mrk 231, Mrk 273, NGC 6240). Theirlarge spatial extent, energetics, and presence of a powerful AGN in each case suggests that an AGN is the power source. Such plumesare not detected in other ultraluminous infrared galaxies which lack clear evidence for an AGN, such as Arp 220.     

Dynamical effects of dark matter in systems of galaxies

SeveralN-body experiments were performed in order to simulate the dynamical behaviour of systems of galaxies gravitationally dominated by a massive dark background.We discuss mass estimates from the dynamics of the luminous component (M _VT) under the influence of such a background, assuming a constant dark/luminous mass ratio (M _D/M _L) and plausible physical conditions. We extend in this way previous studies (Smith, 1980, 1984) about the dependence ofM _VT on the relative distributions of dark and luminous matter (Limber, 1959). We found that the observed ratio of the virial theorem mass to luminosity (M _VT/L) in systems of galaxies of different sizes could be the result of different stages of their post-virialisation evolution as was previously suggested by White and Rees (1978) and Barnes (1983). This evolution is mainly the result of the dynamical friction that dark matter exerts on the luminous component. Thus our results give support to the idea that compact groups of galaxies are dynamically more evolved than large clusters, which is expected from the hierarchical clustering picture for the formation of such structures.