The Quest for the Missing Dust. I. Restoring Large-scale Emission in Herschel Maps of Local Group Galaxies

A measurement of the motion of the Local Group of galaxies through the Universe provides an indication of their peculiar motion relative to the Hubble flow consequent upon the gravitational influence of the local large scale mass inhomogeneities. This motion can be measured either relative to the cosmic microwave background at z ∼ 1000 or relative to the background or nearby (z ∼ 0.01) galaxies. The interpretation of published measurements is subject to some uncertainty. As an example, the Local Group motion derived from optical studies of nearby galaxies (Rubin et al. 1976) differs from that derived from radio frequency measurements of the dipole anisotropy in the microwave background. (Boughn et al. 1981, Gorenstein & Smoot 1981).

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The Physical Properties of Large Scale Systems from Optical Observations

Symposium - International Astronomical Union ◽

10.1017/s0074180900144638 ◽

1978 ◽

Vol 79 ◽

pp. 253-262

Author(s):

G. O. Abell

Keyword(s):

Physical Properties ◽

Large Scale ◽

Local Group ◽

Optical Observations ◽

Local Inhomogeneity ◽

Large Scale Systems ◽

Local Supercluster

Holmberg's (1937) analysis of the distribution of double and multiple galaxies provided what may have been the first hint of a local inhomogeneity of greater scale than that of the Local Group. the idea of a Local Supercluster was subsequently revived by de Vaucouleurs (1953, 1956, 1958). the analyses of others, as well as the continuing study of de Vaucouleurs himself (1976 and references cited therein) have now effectively established the reality of the Local Supercluster. Several other more remote inhomogeneities, or “clouds” of galaxies, were described by Shane and Wirtanen (1954). the writer (Abell 1958) found the distribution of rich clusters to be clumpy, and published a finding list of several apparent superclusters (Abell 1961).

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Elliptical Galaxies and Large-Scale Velocity Flows

Symposium - International Astronomical Union ◽

10.1017/s0074180900135983 ◽

1988 ◽

Vol 130 ◽

pp. 169-176

Author(s):

S. M. Faber ◽

David Burstein ◽

Roger L. Davies ◽

Alan Dressler ◽

Donald Lynden-Bell ◽

...

Keyword(s):

Mass Concentration ◽

Large Scale ◽

Cold Dark Matter ◽

Flow Model ◽

Local Group ◽

Elliptical Galaxies ◽

Local Velocity ◽

Velocity Flow ◽

Large Scale Flow ◽

Double Cluster

Motions of nearby elliptical galaxies reveal a large-scale velocity flow relative to cosmic rest towards the point 1=307±10, b = 9±10. The data are fit best by a two-component flow model. The smaller component is due to Virgo, which induces a velocity at the Local Group of 250 km/s. The main flow is due to a more massive concentration located a distance of 4350±350 km/s towards 1=307, b=9, which induces a local velocity here of 570±60 km/s. This larger component falls off away from the mass concentration roughly as r−1. The Centaurus double cluster and its neighbors are in the direction of the mass concentration but are in the foreground and are falling into it. Galaxy counts, radial velocity surveys, and the motions of nearby spirals are consistent with the above model. The IRAS dipole results are less clear but may also be consistent. There is evidence that the distant mass concentration is non-spherical, with the Centaurus cloud a substantial sub-condensation in the foreground. The formal agreement of the large-scale flow with biased (b=2) cold dark matter is low, but the simple methods used so far to assess this are uncertain. The main weakness of the present data in comparing to theory is the fact that they do not penetrate far enough to show the velocity field on all sides of the mass concentration. Sphericity and total extent of the flow are therefore still unknown.

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Large-Scale Anisotropy at Centimeter Wavelengths

Symposium - International Astronomical Union ◽

10.1017/s0074180900038845 ◽

1983 ◽

Vol 104 ◽

pp. 143-148

Author(s):

David T. Wilkinson

Keyword(s):

Early Universe ◽

Large Scale ◽

Local Group ◽

Virgo Cluster ◽

Scientific Interest ◽

Physical Processes ◽

General Direction ◽

Systematic Effects ◽

Better Than

Scientific interest in large-scale anisotropy measurements is now focused on intrinsic effects, which could tell us much about the early Universe. Current experimental precision of better than 10−4 K begins to probe for interesting physical processes. However, at these levels of precision systematic effects and foreground sources present serious difficulties. Some recent results from balloon flights of a maser radiometer (λ 1.2 cm) and a cooled mixer (λ 3 mm) are discussed and interpreted. The dipole effect gives a velocity for the Local Group in the general direction of the Virgo cluster. The Earth's motion is clearly seen. There is no quadrupole detected at a level of ΔT/T ∼ 5 × 10−5.

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DIVISION VIII: GALAXIES AND THE UNIVERSE

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308024010 ◽

2007 ◽

Vol 3 (T26B) ◽

pp. 179-180

Author(s):

Francesco Bertola ◽

Sadanori Okamura ◽

Virginia L. Trimble ◽

Mark Birkinshaw ◽

Françoise Combes ◽

...

Keyword(s):

Galaxy Clusters ◽

Large Scale ◽

Local Group ◽

Background Radiation ◽

Cosmic Background Radiation ◽

Large Scale Structure ◽

Scale Structure ◽

Cosmic Background ◽

Distant Galaxies ◽

The Universe

Division VIII gathers astronomers engaged in the study of the visible and invisible matter in the Universe at large, from Local Group galaxies via distant galaxies and galaxy clusters to the large-scale structure of the Universe and the cosmic background radiation.

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Acceleration and propagation of ultra high energy cosmic rays in the Local Universe

Bulletin of Taras Shevchenko National University of Kyiv Astronomy ◽

10.17721/btsnua.2018.58.33-36 ◽

2018 ◽

pp. 33-36

Author(s):

V. Voytsekhovsky ◽

B. Hnatyk ◽

Yu. Kudrya

Keyword(s):

Cosmic Rays ◽

Large Scale ◽

Local Group ◽

Mean Free Path ◽

High Energy ◽

Ultra High Energy ◽

Source Position ◽

Local Universe ◽

High Energy Cosmic Rays ◽

Great Attractor

Distribution of matter in the Local Universe (up to ~ 100 Mpc), especially in a Virgo Supercluster region (~20 Mpc) is strongly nonuniform and includes all elements of large scale structure: galaxies and their clusters, superclusters, filaments, sheets and voids. On its smallest scale, our Galaxy and its similar galaxy M31 (Andromeda Nebula) at a distance 770 kpc, together with dozens of dwarf galaxies, form the Local Group of Galaxies. Local group contained in Local Sheet – suchlike pancake concentration of galaxies with radius about 5 Mpc and thickness 1.5 Mpc. This structure is a part of Local Filament – cylindrical region with higher density of matter, that join us to more powerful filament, that concludes Virgo Supercluster and connects two highest matter concentrations in Local Universe – supercluster Great Attractor (70 Mpc) and Perseus-Pisces supercluster (60 Mpc). Extragalactic magnetic field (EGMF) distribution is expected to follow the baryonic matter density distribution. Ultra high energy cosmic rays (UHECRs, E>1018 eV) from extragalactic sources will undergo significant deviations in EGMF, which makes it difficult to search their sources. But for extremely high energy cosmic rays (EHECRs, E>5·1019 eV), that are on the top of cosmic rays energy spectrum (the biggest detected energy of cosmic rays is above 1020 eV), influence of EGMF can be negligible, and their arrival direction can correlate with source position. They carry an important information, about the physics of fundamental interactions beyond the standard model, but still unknown to their origins and mechanisms of acceleration. In addition, a flux of nuclear component of UHECRs decreases in result of nuclear photo-disintegration due to interaction with microwave and infrared background. These processes are significant for protons (hydrogen nuclei), for which the major losses are born of electron-positron pairs and photo-pions reactions. For multi nucleon nucleuses significant process of weakening is photo-disintegration with chemical composition change of main nuclei. In our work we estimate the influence of these factors on the propagation of the UHECRs from sources in the Local Universe, in particular we have investigated the mean free path and magnetic deflection of H(p), He, O, Si and Fe nuclei. For potential sources of UHECRs in the Local Universe, such as Virgo supercluster, Great Attractor and Perseus-Pisces supercluster, we have estimated types and energies of nuclei that can reach the Earth, and, in the same time, can save a connection of arrival directions with source position within 1 rad.

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The All-Sky Extragalactic X-Ray Foreground

International Astronomical Union Colloquium ◽

10.1017/s0252921100077435 ◽

1990 ◽

Vol 123 ◽

pp. 451-455

Author(s):

Elihu Boldt

Keyword(s):

Active Galactic Nuclei ◽

Large Scale ◽

Local Group ◽

Galactic Nuclei ◽

Clusters Of Galaxies ◽

X Ray ◽

Local Space ◽

Dipole Analysis ◽

Statistical Sample ◽

Compact Sources

Observations of galaxies in the IR and optical (Lynden-Bell et al. 1989) suggest that the 600 km/s peculiar velocity of the LG (Local Group of galaxies) arises mainly from a foreground of anisotropically distributed mass within z = 0.013 (i.e., HR < 4000 km/s). Since the X-ray luminosity of bright extragalactic X-ray sources provides a good mass measure of the radiating objects involved and can be observed relatively free of galactic obscuration effects, such sources are likely candidates for serving as reliable tracers of the total underlying mass (i.e., dark as well as visible) responsible for the acceleration of the LG. In this connection, we note that the local gravitational dipole implied by the fifty X-ray brightest clusters of galaxies at z > 0.013 considered by Lahav et al. (1989) is relatively small compared with that inferred from the only three clusters at lower redshifts. Since the local space density of AGN (Active Galactic Nuclei) is about two orders of magnitude greater than rich clusters, however, such compact sources have the potential of providing a vastly improved statistical sample for tracing mass in the low-redshift region of particular interest. Furthermore, recent dipole analysis of the X-ray flux from bright AGN observed with HEAO-1 A2 indicates that they are indeed strong tracers of this matter (Miyaji and Boldt 1990). The implications of this for the very pronounced large-scale foreground anisotropies to be measured via low-redshift AGN resolved in more sensitive all-sky surveys are explored.

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Void asymmetries in the cosmic web: a mechanism for bulk flows

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316010589 ◽

2014 ◽

Vol 11 (S308) ◽

pp. 561-570

Author(s):

J. Bland-Hawthorn ◽

S. Sharma

Keyword(s):

Dark Matter ◽

Cosmic Microwave Background ◽

Large Scale ◽

Local Group ◽

3D Structure ◽

Moving Frame ◽

Microwave Background ◽

Local Universe ◽

Scale Separation

AbstractBulk flows of galaxies moving with respect to the cosmic microwave background are well established observationally and seen in the most recent ΛCDM simulations. With the aid of an idealised Gadget-2 simulation, we show that void asymmetries in the cosmic web can exacerbate local bulk flows of galaxies. The {\it Cosmicflows-2} survey, which has mapped in detail the 3D structure of the Local Universe, reveals that the Local Group resides in a “local sheet” of galaxies that borders a “local void” with a diameter of about 40 Mpc. The void is emptying out at a rate of 16 km s-1Mpc-1. In a co-moving frame, the Local Sheet is found to be moving away from the Local Void at ∼ 260 km s-1. Our model shows how asymmetric collapse due to unbalanced voids on either side of a developing sheet or wall can lead to a systematic movement of the sheet. We conjectured that asymmetries could lead to a large-scale separation of dark matter and baryons, thereby driving a dependence of galaxy properties with environment, but we do {\it not} find any evidence for this effect.

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The Local Supercluster

Symposium - International Astronomical Union ◽

10.1017/s0074180900144572 ◽

1978 ◽

Vol 79 ◽

pp. 205-213 ◽

Cited By ~ 1

Author(s):

G. de Vaucouleurs

Keyword(s):

Small Groups ◽

Large Scale ◽

Local Group ◽

Virgo Cluster ◽

General Phenomenon ◽

Quantitative Evidence ◽

Present Concept ◽

Local Supercluster ◽

Density Excess

The first quantitative evidence for a large scale density excess or “metagalactic cloud” including the Local Group was obtained by Holmberg (1937) and confirmed by Reiz (1941). the present concept of the Local Supercluster (LSC) as a flattened aggregate of field galaxies, small groups and larger clouds centered at the Virgo cluster was formulated 25 years ago (de Vaucouleurs 1953) even before large-scale superclustering was recognized as a general phenomenon. See review papers in Vistas in Astronomy (1956), Soviet Astronomy (1960), Science (1970), Publ. Astron. Soc. Pacific (1971), and IAU Symp. No. 63 (Abell 1974).

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