Bending instabilities at the origin of persistent warps:  A new constraint on dark matter halos

Revaz, Yves; Pfenniger, D.

doi:10.1051/0004-6361:20041386

Cited by 54 publications

(51 citation statements)

References 43 publications

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“…Evidence for large amounts of molecular gas in such regions is also provided by the observed star formation in the extreme outskirts of the HI disc in M 31 (Cuillandre et al 2001). Moreover, N-body simulations show that massive collisionless DM discs are prone to bending instabilities leading to long lasting warps (Revaz & Pfenniger 2004), consistent with the observed high frequency of these structures. This paper shows that if H 2 cores contain most of the Milky Way's DM and have a disc-like distribution, they should be quite easily detectable through a short microlensing experiment targeting the low Galactic latitude Maffei 1 galaxy.…”

Section: Introductionsupporting

confidence: 63%

Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

Fux¹

2005

A&A

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Abstract.A candidate source of dark matter in spiral galaxies is cold molecular hydrogen globules with a condensed central core and a disc-like space distribution probably similar to that of neutral hydrogen. This paper shows that the H 2 cores are sufficiently compact and massive to be detected by microlensing in the outer Galactic disc and that the Maffei 1 elliptical galaxy, at a distance of 3 Mpc and Galactic latitude b = −0.6 • , offers an ideal target for such an experiment. The microlensing optical depth of H 2 cores along the line of sight to this galaxy is estimated to τ ∼ 0.7× 10 −6 if most of the dark mass in the Milky Way resides in such cores, and the typical event timescale to < ∼ 1 day. Detection rates are computed both in the classical and pixel lensing approaches in the I-and K-bands, and for a representative selection of existing observing facilities. In the more efficient pixel lensing case, two 10-h observing runs, separated in time by at least several days, should yield of the order of 10 positive detections at the 5σ level using ground-based 8 m-class telescopes in the K-band or the Hubble Space Telescope ACS camera in the I-band, and the corresponding fraction of events with timescale measurable to an accuracy better than 50% amounts to about 9% and 4% respectively for these observing alternatives.

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Section: Introductionsupporting

confidence: 63%

Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

Fux¹

2005

A&A

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“…One final aspect of the corrugated structure of IC 2233 that is worth noting is that, regardless of its origin, this type of coherent, large-scale pattern can only exist if the gas disk of this LSB spiral is largely self-gravitating (e.g., Bosma 2002; Revaz & Pfenniger 2004). This adds to other recent evidence for "heavy" disks in some LSB disk galaxies based on the analysis of their spiral structure (Fuchs 2002(Fuchs , 2003Masset & Bureau 2003).…”

Section: Warping and Undulations In The Ic 2233 Diskmentioning

confidence: 66%

H I Imaging Observations of Superthin Galaxies. Ii. Ic 2233 and the Blue Compact Dwarf NGC 2537

Matthews

Uson

2007

The Astronomical Journal

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We have used the Very Large Array to image the H i 21 cm line emission in the edge-on Sd galaxy IC 2233 and the blue compact dwarf NGC 2537. We also present new optical B, R, and Hα imaging of IC 2233 obtained with the WIYN telescope. Despite evidence of localized massive star formation in the form of prominent H ii regions and shells, supergiant stars, and a blue integrated color, IC 2233 is a low surface brightness system with a very low global star formation rate ( 0.05 M yr −1 ), and we detect no significant 21 cm radio continuum emission from the galaxy. The H i and ionized gas disks of IC 2233 are clumpy and vertically distended, with scale heights comparable to that of the young stellar disk. Both the stellar and H i disks of IC 2233 appear flared, and we also find a vertically extended, rotationally anomalous component of H i extending to ∼ 2.4d 10 kpc from the midplane. The H i disk exhibits a mild lopsidedness as well as a global corrugation pattern with a period of ∼7d 10 kpc and an amplitude of ∼150d 10 pc. To our knowledge, this is the first time corrugations of the gas disk have been reported in an external galaxy; these undulations may be linked to bending instabilities or to underlying spiral structure and suggest that the disk is largely self-gravitating. Lying at a projected distance of 16 .7 from IC 2233, NGC 2537 has an H i disk with a bright, tilted inner ring and a flocculent, dynamically cold outer region that extends to ∼3.5 times the extent of the stellar light (D 25 ). Although NGC 2537 is rotationally-dominated, we measure H i velocity dispersions as high as σ V ,H i ∼ 25 km s −1 near its center, indicative of significant turbulent motions. The inner rotation curve rises steeply, implying a strong central mass concentration. Our data indicate that IC 2233 and NGC 2537 do not constitute a bound pair and most likely lie at different distances. We also find no compelling evidence of a recent minor merger in either IC 2233 or NGC 2537, suggesting that both are examples of small disk galaxies evolving in relative isolation.

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“…Note that warps and bending instabilities can also form through the torques exerted by a misaligned dark halo, or via accretion of matter (Jiang & Binney, 1999;Bailin & Steinmetz, 2003;Revaz & Pfenniger, 2004).…”

Section: Rings Ripples Shells and Warpsmentioning

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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Bending instabilities at the origin of persistent warps: A new constraint on dark matter halos

Cited by 54 publications

References 43 publications

Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

H I Imaging Observations of Superthin Galaxies. Ii. Ic 2233 and the Blue Compact Dwarf NGC 2537

Tides in Colliding Galaxies

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Bending instabilities at the origin of persistent warps: A new constraint on dark matter halos

Cited by 54 publications

References 43 publications

Detecting cold H2globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

Detecting cold H2globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

H I Imaging Observations of Superthin Galaxies. Ii. Ic 2233 and the Blue Compact Dwarf NGC 2537

Tides in Colliding Galaxies

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Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical

Detecting cold H₂globules in the outer Galactic disc by microlensing towards the Maffei 1 elliptical