The (n, 2n) cross section of 9Be in the energy region 2.0–6.4 MeV

Holmberg, M.; Hansen, J. Lundsgaard

doi:10.1016/0375-9474(69)90669-1

Cited by 62 publications

(92 citation statements)

References 19 publications

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“…at all 5 radial bins and at high significance. 6 This indicates 45Њ that satellite galaxies are preferentially distributed along the major axis of the BGG, in good agreement with the findings of Brainerd (2005), Yang et al (2006), and Azzaro et al (2007), but opposite to the old Holmberg (1969) effect. Note that there is a clear indication that the distribution of red satellites is more strongly aligned with the orientation of the BGG than that of blue satellites, again in good agreement with previous studies (e.g.…”

Section: ϫ1 ϫ1supporting

confidence: 83%

Three Different Types of Galaxy Alignment within Dark Matter Halos

Faltenbacher

Mao

et al. 2007

ApJ

103

125

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Using a large galaxy group catalog based on the Sloan Digital Sky Survey Data Release 4, we measure three different types of intrinsic galaxy alignment within groups: halo alignment between the orientation of the brightest group galaxies (BGG) and the distribution of its satellite galaxies, radial alignment between the orientation of a satellite galaxy and the direction toward its BGG, and direct alignment between the orientation of the BGG and that of its satellites. In agreement with previous studies, we find that satellite galaxies are preferentially located along the major axis. In addition, on scales we find that red satellites are preferentially aligned radially r ! 0.7R vir with the direction to the BGG. The orientations of blue satellites, however, are perfectly consistent with being isotropic. Finally, on scales , we find a weak but significant indication for direct alignment between r ! 0.1R vir satellites and BGGs. We briefly discuss the implications for weak-lensing measurements.

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Section: ϫ1 ϫ1supporting

confidence: 83%

Three Different Types of Galaxy Alignment within Dark Matter Halos

Faltenbacher

Mao

et al. 2007

ApJ

103

125

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“…Satellites to spiral galaxies appear to have a preference for polar orbits. This was first stated by Holmberg (1969) and has been confirmed for the Milky Way (e.g., Lynden-Bell 1982;Majewski 1994) and for other Milky Way-like spirals (Zaritsky et al 1997). Zaritsky & Gonzalez (1999) looked for a dynamical process that could be responsible for this anisotropy through galaxy formation models which start with a spherically symmetric distribution of matter.…”

Section: Alternative Explanationsmentioning

confidence: 72%

The Magellanic Stream, High‐Velocity Clouds, and the Sculptor Group

Putman

Staveley‐Smith

Freeman

et al. 2003

ApJ

291

401

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The Magellanic Stream is a 100 Â 10 filament of gas that lies within the Galactic halo and contains $2 Â 10 8 M of neutral hydrogen. In this paper we present data from the H i Parkes All Sky Survey (HIPASS) in the first complete survey of the entire Magellanic Stream and its surroundings. We also present a summary of the reprocessing techniques used to recover large-scale structure in the Stream. The substantial improvement in spatial resolution and angular coverage compared to previous surveys reveals a variety of prominent features, including bifurcation along the main Stream filament; dense, isolated clouds that follow the entire length of the Stream; head-tail structures; and a complex filamentary web at the head of the Stream where gas is being freshly stripped away from the Small Magellanic Cloud and the Bridge. Debris that appears to be of Magellanic origin extends out to 20 from the main Stream filaments. The Magellanic Stream has a velocity gradient of 700 km s À1 from the Clouds to the tail of the Stream, $390 km s À1 greater than that due to Galactic rotation alone, therefore implying a noncircular orbit. The dual filaments comprising the Stream are likely to be relics from gas stripped separately from the Magellanic Bridge and the SMC. This implies that (1) the Bridge is somewhat older than conventionally assumed; and (2) the Clouds have been bound together for at least one or two orbits. The transverse velocity gradient of the Stream also appears to support long-term binary motion of the Clouds. A significant number of the most elongated cataloged Stream clouds (containing $1% of the Stream mass) have position angles aligned along the Stream. This suggests the presence of shearing motions within the Stream, arising from tidal forces or interaction with the tenuous Galactic halo. As previously noted, clouds within one region of the Stream, along the sight line to the less distant half (southern half on the sky) of the Sculptor Group, show anomalous properties. There are more clouds along this sight line than any other part of the Stream, and their velocity distribution significantly deviates from the gradient along the Stream. We argue that this deviation could be due to a combination of halo material, and not to distant Sculptor clouds, based on a spatial and kinematic comparison between the Sculptor Group galaxies and the anomalous clouds and the lack of cloud detection in the northern half of the group. This result has significant implications for the hypothesis that there might exist distant, massive high-velocity clouds within the Local Group. Cataloged clouds within the Magellanic Stream do not have a preferred scale size. Their mass spectrum f ðM H i Þ / M À2:0 H i and column density spectrum f ðN H i Þ / N À2:8 H i are steep compared with Ly absorbers and galaxies, and similar to the anomalous clouds along the Sculptor Group sight line.

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“…Illustrative examples of this scenario are NGC 3561 ("the guitar") and M 51 ("Whirlpool galaxy"), as shown in Figure 1. However, Holmberg (1969) noted that the condensation of the gravitationally bound companion galaxy would be very unlikely when the jets reach a velocity higher than the escape velocity, which seems to be true in most of the cases. Such an activity from the nuclei of massive galaxies led some authors to classify galaxies with connecting "jets" as radio-galaxies (see e.g.…”

Section: A Controversial Scenariomentioning

confidence: 99%

Tides in Colliding Galaxies

Duc

Renaud

2013

Lecture Notes in Physics

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Long tails and streams of stars are the most noticeable upshots of galaxy collisions. Their origin as gravitational, tidal, disturbances has however been recognized only less than fifty years ago and more than ten years after their first observations. This Review describes how the idea of galactic tides emerged, in particular thanks to the advances in numerical simulations, from the first ones that included tens of particles to the most sophisticated ones with tens of millions of them and state-of-the-art hydrodynamical prescriptions. Theoretical aspects pertaining to the formation of tidal tails are then presented. The third part of the review turns to observations and underlines the need for collecting deep multi-wavelength data to tackle the variety of physical processes exhibited by collisional debris. Tidal tails are not just stellar structures, but turn out to contain all the components usually found in galactic disks, in particular atomic / molecular gas and dust. They host star-forming complexes and are able to form star-clusters or even second-generation dwarf galaxies. The final part of the review discusses what tidal tails can tell us (or not) about the structure and content of present-day galaxies, including their dark components, and explains how tidal tails may be used to probe the past evolution of galaxies and their mass assembly history. On-going deep wide-field surveys disclose many new lowsurface brightness structures in the nearby Universe, offering great opportunities for attempting galactic archeology with tidal tails.

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The (n, 2n) cross section of 9Be in the energy region 2.0–6.4 MeV

Cited by 62 publications

References 19 publications

Three Different Types of Galaxy Alignment within Dark Matter Halos

Three Different Types of Galaxy Alignment within Dark Matter Halos

The Magellanic Stream, High‐Velocity Clouds, and the Sculptor Group

Tides in Colliding Galaxies

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