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Search Results: 1 - 10 of 149734 matches for " H. Salo "
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Observed properties of boxy/peanut/barlens bulges
E. Laurikainen,H. Salo
Physics , 2015, DOI: 10.1007/978-3-319-19378-6_4
Abstract: We review the observed morphological, photometric, and kinematic properties of boxy/peanut (B/P) shape bulges. Nearly half of the bulges in the nearby edge-on galaxies have these characteristics, which fraction is similar to the observed bar fraction in Hubble types earlier than Scd. B/P bulges are generally detected in the edge-on view, but it has been recently demonstrated that barlenses, which are lens-like structures embedded in bars, are the more face-on counterparts of the B/P bulges. Multi-component structural decompositions have shown that B/P/barlens structures are likely to account for most of the bulge light, including the early-type disks harboring most of the bulge mass in galaxies. Cool central disks are often embedded in the B/P/barlens bulges. Barred galaxies contain also dynamically hot classical bulges, but it is not yet clear to what extent they are really dynamically distinct structure components, and to what extent stars wrapped into the central regions of the galaxies during the formation and evolution of bars. If most of the bulge mass in the Milky Way mass galaxies in the nearby universe in- deed resides in the B/P-shape bulges, and not in the classical bulges, that idea needs to be integrated into the paradigm of galaxy formation.
Theories of Punishment in the Age of Mass Incarceration: A Closer Look at the Empirical Problem Silenced by Justificationism (The Brazilian Case)  [PDF]
Salo Carvalho
Open Journal of Social Sciences (JSS) , 2013, DOI: 10.4236/jss.2013.14006
Abstract:

The paper examines three central problems involving punitive social control in recent decades: first, the steady increase in the number of incarcerated people (the phenomenon of great confinement), with special emphasis on the Brazilian case; second, the way criminology interprets contemporary confinement (New Penology); and finally, the lack of a (dogmatic) criminal law theory on the reality of mass incarceration. Incarceration data are presented here as premises in order to inquire about the relations between the (normative-philosophical) theories regarding the justification of punishment and the (empirical) phenomena of mass incarceration. The questions behind the current reflection are therefore about what role criminal theories play in the expansion or contraction of the power to punish (potestas puniendi) and the explanations the justification models offer to the problem of hyper-punishment.

On the Possibilities of a Queer Criminology: Homophobia as the Object of Study in the Criminal Sciences—A Perspective Based on the Brazilian Reality  [PDF]
Salo Carvalho
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.21001
Abstract:

The purpose of this research is to approach queer theories and the critical perspectives of criminology in Brazil by analyzing both the conditions of the possibility and the implications of a queer criminology. Homophobic violence is seen here as the object of study of a queer criminological perspective, whose ambition is the construction of a qualified perspective that is aware of diversity, concerned with human rights and, above all, non-discriminating towards the (positive and negative) political demands of social movements represented by gays, lesbians, bisexuals and transsexuals.

Dynamical modelling of a remarkable four-armed barred spiral galaxy ESO 566-24
P. Rautiainen,H. Salo,R. Buta
Physics , 2003, DOI: 10.1111/j.1365-2966.2004.07561.x
Abstract: ESO 566-24 is an extraordinary barred galaxy, which has four regularly spaced spiral arms in blue light images. This type of four-armed spiral structure, which is rare among the spiral population, is clearly seen also in near-infrared images, and thus is present in the old stellar population. We have constructed dynamical models of ESO 566-24 in order to understand the cause of its four-armed structure. The disk gravitational potential is determined from near-infrared photometry, and the gas dynamics is modelled as inelastically colliding particles. The resulting morphology and kinematics with different assumed pattern speeds, disk vertical thicknesses and dark halo contributions is compared with observations. Our models can reproduce the main morphological features of this galaxy: the four-armed spiral, and the inner and nuclear rings. The pattern speed of the bar in this galaxy is such that the corotation resonance is well outside the bar radius, the resonance radius is 1.6 +/- 0.3 times the bar radius. The four-armed spiral resides in the region between inner and outer 4/1-resonances. Also, the main kinematical features, including bar-induced deviations from circular rotation, are explained by our models. The best fit is obtained when the dark halo contribution is just enough to make the modelled rotation curve match the observed one. This ``minimum halo'' is rather moderate: luminous matter dominates the rotation curve within the disk region.
Comparison of bar strengths in active and non-active galaxies
E. Laurikainen,H. Salo,P. Rautiainen
Physics , 2001, DOI: 10.1086/383462
Abstract: Bar strengths are compared between active and non-active galaxies for a sample of 43 barred galaxies. The relative bar torques are determined using a new technique (Buta and Block 2001), where maximum tangential forces are calculated in the bar region, normalized to the axisymmetric radial force field. We use JHK images of the 2 Micron All Sky Survey. We show a first clear empirical indication that the ellipticies of bars are correlated with the non-axisymmetric forces in the bar regions. We found that nuclear activity appears preferentially in those early type galaxies in which the maximum bar torques are weak and appear at quite large distances from the galactic center. Most suprisingly the galaxies with the strongest bars are non-active. Our results imply that the bulges may be important for the onset of nuclear activity, but that the correlation between the nuclear activity and the early type galaxies is not straightforward.
Overview of the Near-IR S0 Galaxy Survey (NIRS0S)
E. Laurikainen,H. Salo,R. Buta,J. H. Knapen
Advances in Astronomy , 2011, DOI: 10.1155/2011/516739
Abstract: An overview of the results of the near-IR S0 galaxy survey (NIRS0S) is presented. NIRS0S is a magnitude- ( ?mag) and inclination- (<65°) limited sample of ?200 nearby galaxies, mainly S0s, but includes also Sa and E galaxies. It uses deep -band images, typically reaching a surface brightness of 23.5?mag arcsec?2. Detailed visual and photometric classifications were made, for the first time coding also the lenses in a systematic manner. As a comparison sample, a similar sized spiral galaxy sample with similar image quality was used. Based on our analysis, the Hubble sequence was revisited: following the early idea by van den Bergh we suggested that the S0s are spread throughout the Hubble sequence in parallel tuning forks as spirals (S0a, S0b, S0c, etc.). This is evidenced by our improved bulge-to-total ( ) flux ratios in the S0s, reaching small values typical to late-type spirals. The properties of bulges and disks in S0s were found to be similar to those in spirals and, also, the masses and scale parameters of the bulges and disks to be coupled. It was estimated that the spiral bulges brighter than ?20?mag in -band are massive enough to be converted into the bulges of S0s merely by star formation. Bars were found to be fairly robust both in S0s and spirals, but, inspite of that, bars might evolve significantly within the Hubble sequence. 1. Introduction We review the main results of the near-IR S0 galaxy survey (NIRS0S) obtained so far. NIRS0S is a magnitude- ( ?mag) and inclination- (less than 65°) limited sample of ~200 nearby galaxies, mainly S0s, but which includes also Sa spirals and 25 late-type ellipticals. Late-type ellipticals were included to avoid missing any potentially misclassified S0s. The observations were done in the -band, carried out using 3-4-meter-sized ground-based telescopes with subarcsecond pixel resolution. The images are deep, typically reaching a surface brightness of 23.5?mag?arcsec?2 in azimuthally averaged profiles (~2?mag deeper than the 2MASS images), thus allowing the detection of the faint outer disks in S0s. Our main emphasis was to address possible secular evolutionary processes in galaxies by comparing the photometric properties of S0s and spirals, based on similarly selected samples, with similar image quality. In the early classification by Hubble [1], the S0s were an enigmatic group of galaxies between the ellipticals and early-type spirals, and, since then, they have appeared to be important in any galaxy evolutionary model. S0s are suggested to evolve from spirals, either by internal secular processes in
Bars do drive spiral density waves
H. Salo,E. Laurikainen,R. Buta,J. H. Knapen
Physics , 2010, DOI: 10.1088/2041-8205/715/1/L56
Abstract: Recently, Buta etal. (2009) examined the question "Do Bars Drive Spiral Density Waves?", an idea supported by theoretical studies and also from a preliminary observational analysis Block etal (2004). They estimated maximum bar strengths Q_b, maximum spiral strengths Q_s, and maximum m=2 arm contrasts A_2s for 23 galaxies with deep AAT K_s-band images. These were combined with previously published Q_b and Q_s values for 147 galaxies from the OSUBSGS sample and with the 12 galaxies from Block etal(2004). Weak correlation between Q_b and Q_s was confirmed for the combined sample, whereas the AAT subset alone showed no significant correlations between Q_b and Q_s, nor between Q_b and A_2s. A similar negative result was obtained in Durbala etal. (2009) for 46 galaxies. Based on these studies, the answer to the above question remains uncertain. Here we use a novel approach, and show that although the correlation between the maximum bar and spiral parameters is weak, these parameters do correlate when compared locally. For the OSUBSGS sample a statistically significant correlation is found between the local spiral amplitude, and the forcing due to the bar's potential at the same distance, out to 1.6 bar radii (the typical bar perturbation is then of the order of a few percent). Also for the sample of 23 AAT galaxies we find a significant correlation between local parameters out to 1.4 bar radii. Our new results confirm that, at least in a statistical sense, bars do indeed drive spiral density waves.
Bars, ovals and lenses in early-type disk galaxies: probes of galaxy evolution
E. Laurikainen,H. Salo,R. Buta,J. H. Knapen
Physics , 2009, DOI: 10.1088/0004-637X/692/1/L34
Abstract: The origin of S0 galaxies is discussed in the framework of early mergers in a Cold Dark Matter cosmology, and in a scenario where S0s are assumed to be former spirals stripped of gas. From an analysis of 127 early-type disk galaxies (S0-Sa), we find a clear correlation between the scale parameters of the bulge (r_eff) and the disk (h_R), a correlation which is difficult to explain if these galaxies were formed in mergers of disk galaxies. However, the stripping hypothesis, including quiescent star formation, is not sufficient to explain the origin of S0s either, because it is not compatible with our finding that S0s have a significantly smaller fraction of bars (46$\pm$6 %) than their assumed progenitors, S0/a galaxies (93$\pm$5 %) or spirals (64-69 %). Our conclusion is that even if a large majority of S0s were descendants of spiral galaxies, bars and ovals must play an important role in their evolution. The smaller fraction particularly of strong bars in S0 galaxies is compensated by a larger fraction of ovals/lenses (97$\pm$2 % compared to 82-83 % in spirals), many of which might be weakened bars. We also found massive disk-like bulges in nine of the S0 galaxies, bulges which might have formed at an early gas-rich stage of galaxy evolution.
Near-IR Atlas of S0-Sa galaxies (NIRS0S)
E. Laurikainen,H. Salo,R. Buta,J. H. Knapen
Physics , 2011, DOI: 10.1111/j.1365-2966.2011.19283.x
Abstract: An atlas of Ks-band images of 206 early-type galaxies is presented, including 160 S0-S0/a galaxies, 12 ellipticals, and 33 Sa galaxies. A majority of the Atlas galaxies belong to a magnitude-limited (mB<12.5 mag) sample of 185 NIRS0S (Near-IR S0 galaxy Survey) galaxies. To assure that mis-classified S0s are not omitted, 25 ellipticals from RC3 classified as S0s in the Carnegie Atlas were included in the sample. The images are 2-3 mag deeper than 2MASS images. Both visual and photometric classifications are made. Special attention is paid to the classification of lenses, coded in a systematic manner. A new lens-type, called a 'barlens', is introduced. Also, boxy/peanut/x-shaped structures are identified in many barred galaxies, even-though the galaxies are not seen in edge-on view, indicating that vertical thickening is not enough to explain them. Multiple lenses appear in 25% of the Atlas galaxies, which is a challenge to the hierarchical evolutionary picture of galaxies. Such models need to explain how the lenses were formed and survived in multiple merger events that galaxies may have suffered during their lifetimes. Following the early suggestion by van den Bergh, candidates of S0c galaxies are shown, which galaxies are expected to be former Sc-type spirals stripped out of gas.
Ring Star Formation Rates in Barred and Nonbarred Galaxies
R. D. Grouchy,R. J. Buta,H. Salo,E. Laurikainen
Physics , 2010, DOI: 10.1088/0004-6256/139/6/2465
Abstract: Nonbarred ringed galaxies are relatively normal galaxies showing bright rings of star formation in spite of lacking a strong bar. This morphology is interesting because it is generally accepted that a typical ring forms when material collects near a resonance, set up by the pattern speed of a bar or bar-like perturbation. Our goal in this paper is to examine whether the ring star formation properties are related to the non-axisymmetric gravity potential in general. For this purpose, we obtained H{\alpha} emission line images and calculated the line fluxes and star formation rates (SFRs) for 16 nonbarred SA galaxies and four weakly barred SAB galaxies with rings. For comparison, we combine our observations with a re-analysis of previously published data on five SA, seven SAB, and 15 SB galaxies with rings, three of which are duplicates from our sample. With these data, we examine what role a bar may play in the star formation process in rings. Compared to barred ringed galaxies, we find that the inner ring SFRs and H{\alpha}+[N ii] equivalent widths in nonbarred ringed galaxies show a similar range and trend with absolute blue magnitude, revised Hubble type, and other parameters. On the whole, the star formation properties of inner rings, excluding the distribution of H ii regions, are independent of the ring shapes and the bar strength in our small samples. We confirm that the deprojected axis ratios of inner rings correlate with maximum relative gravitational force Q_g; however, if we consider all rings, a better correlation is found when local bar forcing at the radius of the ring, Q_r, is used. Individual cases are described and other correlations are discussed. By studying the physical properties of these galaxies, we hope to gain a better understanding of their placement in the scheme of the Hubble sequence and how they formed rings without the driving force of a bar.
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