Empirical distributions of galactic   spin parameters from the Sloan Digital Sky Survey

Hernández, X.; Park, Changbom; Cervantes-Sodi, B.; Choi, Yun‐Young

doi:10.1111/j.1365-2966.2006.11274.x

Cited by 48 publications

(97 citation statements)

References 41 publications

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“…The spheroids have always lower median values than the disk galaxies (see also Table 5 for the fitting parameters). Observationally, Hernandez et al (2007) also found that the spiral galaxies on average have larger λ-values than the ellipticals of their sample. However, this was not seen in previous studies by Sales et al (2012) and Scannapieco et al (2009), who did not find a correlation between galaxy type and the spin parameter.…”

Section: The Spin Parameter λ Of the Host Halosmentioning

confidence: 81%

“…Hernandez & Cervantes-Sodi (2006) calculated the λ-parameter for two galaxy samples with a total of 337 observed spirals and found that with decreasing bulge-to-disk ratio the spirals have increasing λ-values. In a further study Hernandez et al (2007) investigated a sample of 11,597 spiral and elliptical galaxies from the Sloan Digital Sky Survey (SDSS) and found that ellipticals on average have lower λ-values than spiral galaxies.…”

Section: Introductionmentioning

confidence: 99%

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Connecting Angular Momentum and Galactic Dynamics: The Complex Interplay Between Spin, Mass, and Morphology

Teklu

Remus

Dolag

et al. 2015

ApJ

251

253

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The evolution and distribution of the angular momentum of dark matter (DM) halos have been discussed in several studies over the past decades. In particular, the idea arose that angular momentum conservation should allow us to infer the total angular momentum of the entire DM halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especially for disk galaxies. To test this idea and to understand the connection between the angular momentum of the DM halo and its galaxy, we use a state-of-the-art, hydrodynamical cosmological simulation taken from the set of Magneticum Pathfinder simulations. Thanks to the inclusion of the relevant physical processes, the improved underlying numerical methods, and high spatial resolution, we successfully produce populations of spheroidal and disk galaxies self-consistently. Thus, we are able to study the dependence of galactic properties on their morphology. We find that(1) the specific angular momentum of stars in disk and spheroidal galaxies as a function of their stellar mass compares well with observational results; (2) the specific angular momentum of the stars in disk galaxies is slightly smaller compared to the specific angular momentum of the cold gas, in good agreement with observations; (3) simulations including the baryonic component show a dichotomy in the specific stellar angular momentum distribution when splitting the galaxies according to their morphological type(this dichotomy can also be seen in the spin parameter, where disk galaxies populate halos with slightly larger spin compared to spheroidal galaxies); (4) disk galaxies preferentially populate halos in which the angular momentum vector of the DM component in the central part shows a better alignment to the angular momentum vector of the entire halo; and (5) the specific angular momentum of the cold gas in disk galaxies is approximately 40% smaller than the specific angular momentum of the total DM halo and shows a significant scatter.

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Section: The Spin Parameter λ Of the Host Halosmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Connecting Angular Momentum and Galactic Dynamics: The Complex Interplay Between Spin, Mass, and Morphology

Teklu

Remus

Dolag

et al. 2015

ApJ

251

253

View full text Add to dashboard Cite

show abstract

“…The only unobservable quantity M halo can be replaced by M baryon /F where F is the baryonic fraction, or, alternatively, M * /F d where F d is the stellar disk mass fraction. Based on this framework Hernandez et al (2007) analyzed the empirical λ distribution of samples taken from the SDSS. Because their sample lacked direct measures of V rot , those authors invoked the Tully-Fisher relation to infer V rot from the disk luminosity.…”

Section: Spin Parameters Derived From the Tully-fisher Relationmentioning

confidence: 99%

“…We also require that the r-band light profile should be better fitted by an exponential profile than a deVaucouleurs profile to be sure we were including mainly disk galaxies. Since Hernandez et al (2007) ignored internal extinction but we have corrected for it using the SED fitting estimate of A R , the b/a requirement in our case is less strict, b/a > 0.35. Such a cut is adopted so that the b/a distribution is close to being flat above 0.35.…”

Section: Spin Parameters Derived From the Tully-fisher Relationmentioning

confidence: 99%

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The Arecibo Legacy Fast Alfa Survey: The Galaxy Population Detected by Alfalfa

Huang

Haynes

Giovanelli

et al. 2012

ApJ

296

447

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Making use of HI 21 cm line measurements from the ALFALFA survey (α.40) and photometry from the Sloan Digital Sky Survey (SDSS) and GALEX, we investigate the global scaling relations and fundamental planes linking stars and gas for a sample of 9417 common galaxies: the α.40-SDSS-GALEX sample. In addition to their HI properties derived from the ALFALFA dataset, stellar masses (M * ) and star formation rates (SFRs) are derived from fitting the UV-optical spectral energy distributions. 96% of the α.40-SDSS-GALEX galaxies belong to the blue cloud, with the average gas fraction f HI ≡ M HI /M * ∼ 1.5. A transition in SF properties is found whereby below M * ∼ 10 9.5 M ⊙ , the slope of the star forming sequence changes, the dispersion in the specific star formation rate (SSFR) distribution increases and the star formation efficiency (SFE) mildly increases with M * . The evolutionary track in the SSFR-M * diagram, as well as that in the color magnitude diagram are linked to the HI content; below this transition mass, the star formation is regulated strongly by the HI. Comparison of HI-and optically-selected samples over the same restricted volume shows that the HI-selected population is less evolved and has overall higher SFR and SSFR at a given stellar mass, but lower SFE and extinction, suggesting either that a bottleneck exists in the HI to H 2 conversion, or that the process of SF in the very HI-dominated galaxies obeys an unusual, low efficiency star formation law. A trend is found that, for a given stellar mass, high gas fraction galaxies reside preferentially in dark matter halos with high spin parameters. Because it represents a full census of HI-bearing galaxies at z ∼ 0, the scaling relations and fundamental planes derived for the ALFALFA population can be used to assess the HI detection rate by future blind HI surveys and intensity mapping experiments at higher redshift.

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Generation of angular momentum in cold gravitational collapse

Benhaiem

Joyce

Labini

et al. 2016

A&A

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During the violent relaxation of a self-gravitating system, a significant fraction of its mass may be ejected. If the time-varying gravitational field also breaks spherical symmetry, this mass can potentially carry angular momentum. Thus, starting initial configurations with zero angular momentum can, in principle, lead to a bound virialised system with non-zero angular momentum. Using numerical simulations we explore here how much angular momentum can be generated in a virialised structure in this way, starting from configurations of cold particles that are very close to spherically symmetric. For the initial configurations in which spherical symmetry is broken only by the Poissonian fluctuations associated with the finite particle number N, with N in range 10 3 to 10 5 , we find that the relaxed structures have standard "spin" parameters λ ∼ 10 −3 , and decreasing slowly with N. For slightly ellipsoidal initial conditions, in which the finite-N fluctuations break the residual reflection symmetries, we observe values λ ∼ 10 −2 , i.e. of the same order of magnitude as those reported for elliptical galaxies. The net angular momentum vector is typically aligned close to normal to the major semi-axis of the triaxial relaxed structure and of the ejected mass. This simple mechanism may provide an alternative, or complement, to the so-called tidal torque theory for understanding the origin of angular momentum in astrophysical structures.

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Empirical distributions of galactic spin parameters from the Sloan Digital Sky Survey

Cited by 48 publications

References 41 publications

Connecting Angular Momentum and Galactic Dynamics: The Complex Interplay Between Spin, Mass, and Morphology

Connecting Angular Momentum and Galactic Dynamics: The Complex Interplay Between Spin, Mass, and Morphology

The Arecibo Legacy Fast Alfa Survey: The Galaxy Population Detected by Alfalfa

Generation of angular momentum in cold gravitational collapse

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