Holmberg Effect Research Articles

A New Method of Investigation of the Orientation of Galaxies in Clusters in the Absence of Information on Their Morphological Types

The analysis of the orientation of galaxies is one of the most widely used tools in the fields of extragalactic astronomy and cosmology, enabling the verification of structure formation scenarios in the universe. It is based on the statistical analysis of the distribution of angles, giving the spatial orientation of galaxies in space. In order to obtain the correct analysis results, one is obliged to take into account the Holmberg effect and the fact that galaxies are oblate spheroids, with the real axis ratio depending on the morphological type. However, most of the astronomical data available today do not contain information about the morphological types of galaxies. The analysis of sufficiently numerous observational data allows one to calculate the estimated frequency of the occurrence of given morphological types used in the proposed method. As a part of this, on the basis of these frequencies, simulations were performed, which enabled us to recognize new angle distributions used in orientation studies. These distributions already contain information on the frequency of the appearance of galaxies of particular morphological types in clusters, allowing for more accurate results of the statistical tests carried out during the analysis. The method is an extension of results developed in in our previous investigations.

Stellar Populations of Galaxies in the LAMOST Spectral Survey

Abstract We first derive the stellar population properties: age and metallicity for ∼43,000 low redshift galaxies in the DR7 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey, which have no spectroscopic observations in the Sloan Digital Sky Survey (SDSS). We employ a fitting procedure based on the small-scale features of galaxy spectra so as to avoid possible biases from the uncertain flux calibration of the LAMOST spectroscopy. We show that our algorithm can successfully recover the average age and metallicity of the stellar populations of galaxies down to signal-to-noise ratio ≥5 through testing on both mock galaxies and real galaxies comprising LAMOST and their SDSS counterparts. We provide a catalog of the age and metallicity for ∼43,000 LAMOST galaxies online. As a demonstration of the scientific application of this catalog, we present the Holmberg effect on both age and metallicity of a sample of galaxies in galaxy pairs.

NO THE HOLMBERG EFFECT FOR GALAXY PAIRS SELECTED FROM THE SDSS DR9 AT Z ≤ 0:06

We studied the Holmberg effect in galaxy pairs selected from the SDSS DR9, where 60561galaxies were limited by redshift 0.02 −21.5 m for neighbor galaxies (N=41983). We have made a morphological classification for each galaxy using both the visual inspection and machine learning methods. We considered four morphological types of galaxy pairs (E, early, and L, late, types) for testing the Holmberg effect: E- E, E-L, L-E, L-L (first companion of pairs is a central galaxy and second one is a faint satellite galaxy). We concluded about the absence of the Holmberg effect: Rg−i = 0.3 for L-E pairs at 0.04 < z ≤ 0.06 and Rg−i = 0.2 for E-E and E-L pairs at 0.02 ≤ z ≤ 0.04. Summarizing, a correlation of color indices in pairs for the samples of galaxies composed with the half of large sky surveys likely SDSS was not confirmed or confirmed partially. The Holmberg effect is rather connected with morphological types of galaxies than with their color indices. Taking into account a scenario of the secular evolution, the presence of at least one elliptical galaxy in pair may be indicator of previous mergers in the earlier epoch. So, figuring manifestations of the Holmberg effect in its original interpretation no longer seems such urgent.

HERSCHEL OBSERVATIONS OF MAJOR MERGER PAIRS AT z = 0: DUST MASS AND STAR FORMATION

ABSTRACT We present Herschel PACS and SPIRE far-infrared (FIR) and submillimeter imaging observations for a large K-band selected sample of 88 close major-merger pairs of galaxies (H-KPAIRs) in 6 photometric bands (70, 100, 160, 250, 350, and 500 μm). Among 132 spiral galaxies in the 44 spiral–spiral (S+S) pairs and 44 spiral–elliptical (S+E) pairs, 113 are detected in at least 1 Herschel band. The star formation rate (SFR) and dust mass (M dust) are derived from the IR SED fitting. The mass of total gas (M gas) is estimated by assuming a constant dust-to-gas mass ratio of 0.01. Star-forming spiral galaxies (SFGs) in S+S pairs show significant enhancements in both specific star formation rate (sSFR) and star formation efficiency (SFE), while having nearly the same gas mass compared to control galaxies. On the other hand, for SFGs in S+E pairs, there is no significant sSFR enhancement and the mean SFE enhancement is significantly lower than that of SFGs in S+S pairs. This suggests an important role for the disk–disk collision in the interaction-induced star formation. The M gas of SFGs in S+E pairs is marginally lower than that of their counterparts in both S+S pairs and the control sample. Paired galaxies with and without interaction signs do not differ significantly in their mean sSFR and SFE. As found in previous works, this much larger sample confirms that the primary and secondary spirals in S+S pairs follow a Holmberg effect correlation on sSFR.

Morphology and color indices of galaxies in Pairs: Criteria for the classification of galaxies

We have examined the relationship between the morphological types and the u-r, g-i, and r-z color indices of 365 pairs of galaxies with radial velocities 3000<V<9500 km/s selected from the SDSS DR5 survey using the second order Voronoi tesselation method. It is shown that the paired galaxies include a smaller fraction of blue compact galaxies than isolated galaxies. Using the relationship between the color index and a parameter such as the inverse concentration index, absolute magnitude, and the de Vaucouleurs or scale radius, we propose a “color indices criterion” for the morphological classification of galaxies into three classes: (1) elliptical and lenticular E-S0, (2) spiral Sa-Scd, and (3) late spiral Sd-Sdm and irregular Im/BCG. We did not detect the Holmberg effect in our sample; the correlation found in the color indices of the components of galactic pairs is fully explained by the dependence of the morphological type of a galaxy on its color index.

Dependence of the holmberg effect on separations between paired galaxies

To investigate the dependence of the Holmberg effect of paired galaxies on three-dimensional separations, we have constructed four subsamples characterized by three-dimensional separations s ≤ 50 kpc, 50 kpc < s ≤ 100 kpc , 100kpc < s ≤150kpc , and 150 kpc < s ≤ 200 kpc , respectively. In this study, linear correlation coefficients and surplus standard deviations of color indices, luminosity, and size between two components of paired galaxies are calculated. It is found that there is a weak tendency for correlation coefficients of color indices to increase with decreasing three-dimensional separations, but such a tendency does not exist for ones of luminosity and size. We also note that there is no tendency for surplus standard deviations to decrease with decreasing three-dimensional separations. This suggests that it is still very difficult to clearly affirm the dependence of the Holmberg Effect of paired galaxies on three-dimensional separations.

LOCAL BENCHMARKS FOR THE EVOLUTION OF MAJOR-MERGER GALAXIES—SPITZEROBSERVATIONS OF AK-BAND SELECTED SAMPLE

We present Spitzer observations for a sample of close major-merger galaxy pairs (KPAIR sample) selected from cross-matches between the Two Micron All Sky Survey and Sloan Digital Sky Survey Data Release 3. The goals are to study the star formation activity in these galaxies and to set a local bench mark for the cosmic evolution of close major mergers. The Spitzer KPAIR sample (27 pairs, 54 galaxies) includes all spectroscopically confirmed spiral–spiral (S+S) and spiral–elliptical (S+E) pairs in a parent sample that is complete for primaries brighter than K = 12.5 mag, projected separations of 5 h−1 kpc ⩽ s ⩽ 20 h−1 kpc, and mass ratios ⩽2.5. The Spitzer data, consisting of images in seven bands (3.6, 4.5, 5.8, 8, 24, 70, 160 μm), show very diversified IR emission properties. Compared to single spiral galaxies in a control sample, only spiral galaxies in S+S pairs show significantly enhanced specific star formation rate (sSFR = SFR/M), whereas spiral galaxies in S+E pairs do not. Furthermore, the SFR enhancement of spiral galaxies in S+S pairs is highly mass-dependent. Only those with M ≳ 1010.5 M☉ show significant enhancement. Relatively low-mass (M ∼ 1010 M☉) spirals in S+S pairs have about the same SFR/M compared to their counterparts in the control sample, while those with 1011 M☉ have on average a ∼3 times higher SFR/M than single spirals. There is evidence for a correlation between the global star formation activities (but not the nuclear activities) of the component galaxies in massive S+S major-merger pairs (the "Holmberg effect"). There is no significant difference in the SFR/M between the primaries and the secondaries, nor between spirals of SEP < 1 and those of SEP ⩾ 1, SEP being the normalized separation parameter. The contribution of KPAIR galaxies to the cosmic SFR density in the local universe is only 1.7%, and amounts to .

The Holmberg effect of Luminous Red Galaxy (LRG) pairs of the SDSS Data Release 4 (SDSS4)

AbstractWe investigate the Holmberg effect of Luminous Red Galaxy (LRG) pairs of the SDSS Data Release 4 (SDSS4). It is found that the Holmberg effect of LRG pairs has no statistical significance. According to types of the two components in each pair, we divide the isolated LRG pair sample into three subsamples: the early+early subsample, the late+late subsample and the early+late subsample. Further analyses show that all LRG pair subsamples do not exhibit statistically significant Holmberg effect. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

The Locations of Satellite Galaxies in a ΛCDM Universe

We compute the locations of satellite galaxies with respect to their hosts using the ΛCDM GIF simulation. If the major axes of the hosts' images are perfectly aligned with the major axes of the projected mass, the satellites are located preferentially close to the hosts' major axes. In this case, the degree of anisotropy in the satellite locations is a good tracer of the flattening of the hosts' halos. If all hosts have luminous circular disks, the symmetry axes of the projected mass and light are not perfectly aligned, and the locations of the satellites depend on how the hosts' disks are placed within their halos. If the disk angular momentum vectors are aligned with the major axes of the halos, the satellites show a pronounced Holmberg effect. If the disk angular momentum vectors are aligned with the intermediate axes of the local large-scale structure, the distribution of the satellite locations is essentially isotropic. If the disk angular momentum vectors are aligned with either the minor axes or with the net angular momentum vectors of the halos, the satellites are distributed anisotropically about their hosts, with a preference for being found near the hosts' major axes. This agrees well with the observation that satellite galaxies in the Sloan Digital Sky Survey tend to be found near the major axes of their hosts and suggests that the mass and light of SDSS host galaxies must be fairly well aligned in projection on the sky.

The Anisotropic Distribution of M31 Satellite Galaxies: A Polar Great Plane of Early-type Companions

The highly anisotropic distribution and apparent alignment of the Galactic satellites in polar great planes begs the question of how common such distributions are. The satellite system of M31 is the only nearby system for which we currently have sufficiently accurate distances to study the three-dimensional satellite distribution. We present the spatial distribution of the 15 currently known M31 companions in a coordinate system centered on M31 and aligned with its disk. Through a detailed statistical analysis we show that the full satellite sample describes a plane that is inclined by -56° with respect to the poles of M31 and has an rms height of 100 kpc. At 88% the statistical significance of this plane is low, and it is unlikely to have a physical meaning. We note that the great stellar stream found near Andromeda is inclined to this plane by 7°. Most of the M31 satellites are found within <±40° of M31's disk; i.e., there is little evidence for a Holmberg effect. If we confine our analysis to early-type dwarfs, we find a best-fit polar plane within 5°-7° from the pole of M31. This polar great plane has a statistical significance of 99.7% and includes all dSphs (except for And II), M32, NGC 147, and PegDIG. The rms distance of these galaxies from the polar plane is 16 kpc. The nearby spiral M33 has a distance of only ∼3 kpc from this plane, which points toward the M81 group. We discuss the anisotropic distribution of M31's early-type companions in the framework of three scenarios, namely, as remnants of the breakup of a larger progenitor, as a tracer of a prolate dark matter halo, and as a tracer of collapse along large-scale filaments. The first scenario requires that the breakup must have occurred at very early times and that the dwarfs continued to form stars thereafter to account for their stellar population content and luminosity-metallicity relation. The third scenario seems to be plausible, especially when considering the apparent alignment of our potential satellite filament with several nearby groups. The current data do not permit us to rule out any of the scenarios. Orbit information is needed to test the physical reality of the polar plane and of the different scenarios in more detail.

Anisotropic Distribution of SDSS Satellite Galaxies: Planar (Not Polar) Alignment

The distribution of satellite galaxies relative to isolated host galaxies in the Sloan Digital Sky Survey (SDSS) is investigated. Host-satellite systems are selected using three different methods, yielding samples of ~3300, ~1600, and ~950 satellites. In the plane of the sky, the distributions of all three samples show highly significant deviations from circular symmetry (>99.99%, >99.99%, and 99.79% confidence levels, respectively), and the degree of anisotropy is a strong function of the projected radius, rp, at which the satellites are found. For rp 100 kpc, the SDSS satellites are aligned preferentially with the major axes of the hosts. This is in stark contrast to the Holmberg effect, in which satellites are aligned with the minor axes of host galaxies. The degree of anisotropy in the distribution of the SDSS satellites decreases with rp and is consistent with an isotropic distribution at of order the 1 σ level for 250 kpc rp 500 kpc.

Cyclic Linearization of Syntactic Structure

This paper proposes an architecture for the mapping between syntax and phonology — in particular, that aspect of phonology that determines ordering. In Fox and Pesetsky (in prep.), we will argue that this architecture, when combined with a general theory of syntactic domains (phases), provides a new understanding of a variety of phenomena that have received diverse accounts in the literature. This shorter paper focuses on two processes, both drawn from Scandinavian: the familiar process of Object Shift and the less well-known process of Quantifier Movement. We will argue that constraints on these operations can be seen as instances of the same property of grammar that explains the fact that movement is local and successive cyclic. We begin by sketching a model in which locality and successive cyclicity are consequences of the architecture that we propose, rather than specific facts about movement itself. We next present our proposal in somewhat greater detail, and show how it can account for a wide range of apparent limitations on movement — in particular, superficially contradictory restrictions on Object Shift and Quantifier Movement. The restrictions on Object Shift include those grouped under the rubric of Holmberg's Generalization, which Quantifier Movement does not seem to obey. We will argue that Quantifier Movement instead obeys a near mirror-image of Holmberg's Generalization (an Inverse Holmberg Effect), but that both Holmberg's Generalization and its mirror image are expected if our proposed architecture is correct. Our discussion will be for the most part informal, but we will conclude by offering a more formal implementation of our proposals. This implementation will belong to a family of

Merging Galaxies in the Sloan Digital Sky Survey Early Data Release

We present a new catalog of merging galaxies obtained through an automated systematic search routine. The 1479 new pairs of merging galaxies were found in ≈462 square degrees of the Sloan Digital Sky Survey Early Data Release (SDSS EDR) photometric data, and the pair catalog is complete for galaxies in the magnitude range 16.0 ≤ g* ≤ 20. The selection algorithm, implementing a variation on the original Karachentsev criteria, proved to be very efficient and fast. Merging galaxies were selected such that the intergalaxy separations were less than the sum of the component galaxies' radii. We discuss the characteristics of the sample in terms of completeness, pair separation, and the Holmberg effect. We also present an on-line atlas of images for the SDSS EDR pairs obtained using the corrected frames from the SDSS EDR database. The atlas images also include the relevant data for each pair member. This catalog will be useful for conducting studies of the general characteristics of merging galaxies, their environments, and their component galaxies. The redshifts for a subset of the interacting and merging galaxies and the distribution of angular sizes for these systems indicate the SDSS provides a much deeper sample than almost any other wide-area catalog to date.

BVRIsurface photometry of mixed morphology pairs of galaxies

In order to analyze the photometric signature of gravitational interactions in spiral and elliptical galaxies, we present results of multicolor broad band (BVRI) surface photometry for a second set of 10 mixed pairs drawn from the Karachentsev Catalogue of Isolated Pairs of Galaxies (KPG). We report total magnitudes and colors, as well as surface brightness, color and geometric (ϵ, PA and ) profiles. Most of this subsample have photometric parameters homogeneously derived for the first time. Internal and external data comparisons show consistency within the estimated errors. We find 1 true (E+S) pair and 4 probable (E+S) pairs ((E/S0+S) cases) in the present sample. The remaining objects include 3 lenticular-spiral (S0+S) systems, 1 spiral-spiral (S+S) pair and 1 probable spiral-spiral pair ((S0/Sa+S) case). Four lenticular galaxies show evidence of underlying (perhaps induced) structures like bars/arms. Among the spiral components, an over-representation of early (Sa-Sb) types was found. A brief discussion on the existence of a Holmberg Effect is also presented.

Anisotropy in the distribution of satellites around primary galaxies in the 2dF Galaxy Redshift Survey: the Holmberg effect

We have analysed a sample of satellite and primary galaxies in the 2dF Galaxy Redshift Survey. In our study we find strong statistical evidence of the Holmberg effect (that is, a tendency for satellites to avoid regions along the line defined by the primary plane) within 500 kpc of the projected distance to the primary. This effect is present only when we restrict our analysis to objects with radial velocity relative to the primary |Δν| < 160 km s -1 , which corresponds approximately to the mean of the distribution. We explore the dependence of this anisotropy on spectral type (η), colours and luminosities of both primaries and satellites, finding that objects with a low present-day star formation rate present the most significant effect.

Anisotropy in the Distribution of Satellite Galaxy Orbits

Nearby clusters such as Virgo and Coma possess galaxy distributions that tend to be aligned with the principal axis of the cluster itself. This has also been confirmed by a recent statistical analysis of some 300 Abell clusters, where the effect has been linked to the dynamical state of the cluster. Moreover, the orbits of satellite galaxies in galactic systems like our own Milky Way also demonstrate a high degree of anisotropy—the so-called Holmberg effect, the origin of which has been the subject of debate for more than 30 years. This study presents the analysis of cosmological simulations focusing on the orbits of satellite galaxies within dark matter halos. The apocenters of the orbits of these satellites are preferentially found within a cone of opening angle ~40° around the major axis of the host halo, in accordance with the observed anisotropy found in galaxy clusters. We do, however, note that a link to the dynamical age of the cluster is not well established, as both of our oldest dark matter halos do show a clear anisotropy signal. Further analysis connects this distribution to the infall pattern of satellites along the filaments: the orbits are determined rather by the environment of the host halo than some "dynamical selection" during their life within the host's virial radius.

$\vec{BVRI}$ surface photometry of (S+S) binary galaxies

We present multicolour broad band (BVRI) photometry for a sample of 33 spiral-spiral (S+S) binary galaxies drawn from the Karachentsev Catalogue of Isolated Pairs of Galaxies (KPG). The data is part of a joint observational programme devoted to systematic photometric study of one of the most complete and homogeneous pair samples available in the literature. We present azimuthally averaged colour and surface brightness profiles, colour index () maps, B band and sharp/filtered B band images as well as integrated magnitudes, magnitudes at different circular apertures and integrated colours for each pair. Internal and external data comparisons show consistency within the estimated errors. Two thirds of the sample have total aperture parameters homogeneously derived for the first time. After reevaluating morphology for all the pairs, we find a change in Hubble type for 24 galaxies compared to the original POSS classifications. More than half of our pairs show morphological concordance which could explain, in part, the strong correlation in the () colour indices (Holmberg Effect) between pair components. We find a tendency for barred galaxies to show grand design morphologies and flat colour profiles. The measurements will be used in a series of forthcoming papers where we try to identify and isolate the main structural and photometric properties of disk galaxies at different stages of interaction.

NGC 5084: A Massive Disk Galaxy Accreting its Satellites?

view Abstract Citations (20) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS NGC 5084: A Massive Disk Galaxy Accreting its Satellites? Carignan, Claude ; Cote, Stephanie ; Freeman, Kenneth C. ; Quinn, Peter J. Abstract The spectra of 34 galaxies within 20 arcmins ( ~ 100 kpc) of the lenticular galaxy NGC 5084 have been obtained using the FOCAP system on the Anglo-Australian 3.9m telescope. Nine objects are found with projected separations ≲ 80 kpc and with radial velocities within +/- 630 km s(-1) of the parent galaxy redshift. Using various techniques, their velocity differences and projected separations are used to estimate the mass of this S0 galaxy, which ranges from 6 x 10(12) Msun to 1 x 10(13) Msun. With such a mass, NGC 5084 is one of the most massive disk galaxy known, with a (M/L_B) gtrsim 200 Msun/Lsun. In agreement with the models' predictions of Quinn & Goodman (1986) but contrary to the results of Zaritsky et al (1993) obtained from their statistical sample, the properties of the satellites' population show no evidence for the ``Holmberg effect'' and a clear excess of satellites in retrograde orbits. Several signs hint that this S0 galaxy has survived the accretion of several satellites. Publication: The Astronomical Journal Pub Date: May 1997 DOI: 10.1086/118376 arXiv: arXiv:astro-ph/9704032 Bibcode: 1997AJ....113.1585C Keywords: Astrophysics E-Print: 20 pages Latex (aasms4.sty) including all tables and 4 postscript figures. AJ in Press full text sources arXiv | ADS | data products NED (30) SIMBAD (10)

Satellites of spiral galaxies

We present a survey of satellites around a homogeneous set of late- type spirals with luminosity similar to that of the Milky Way. The survey aims to probe the mass distribution at galactocentric radii ~250 kpc. The 69 satellites in our sample span a range of magnitudes similar to that of the brighter satellites in the Local Group. Slightly over half the objects are new discoveries. Existing data were supplemented by our observations of radial velocities to obtain km s^-1^ precision. In this paper we present the data and carry out a first-cut dynamical analysis. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a "typical" isolated spiral. The projected density profile of the ensemble falls off approximately as r^-1^. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the `` Holmberg effect," an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km s^-1^ in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Naive mass estimates suggest that the mass contained within 200 kpc is of order 2 x 10^12^ M_sun_. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

On the Holmberg asymmetry of the satellites of disk galaxies

A tidal explanation for the observation by Holmberg that the satellites of edge-on disk galaxies tend to avoid the sector within + or - 30 deg of the major axes of the disk galaxies is considered. It is shown that satellites with small orbit-to-disk inclinations are likely to become compact and consequently be left out in Holmberg's survey due to the resemblance to stars. The explanation is supported by the observation of an excess of compact galaxies near the major-axis direction of edge-on disk galaxies. The disk tidal explanation also predicts that the asymmetry should be weaker with larger satellites. It is found that the Karachentsev (1972, 1980) binary galaxy sample, where the typical companion is comparable to the primary galaxy, shows no Holmberg effect. The case of M32 as a compact satellite of the Andromeda galaxy is discussed as a nearby observationally supported example of the above processes.