scholarly journals CHILES VI: H i and H α observations for z < 0.1 galaxies; probing H i spin alignment with filaments in the cosmic web

2019 ◽  
Vol 492 (1) ◽  
pp. 153-176 ◽  
Author(s):  
J Blue Bird ◽  
J Davis ◽  
N Luber ◽  
J H van Gorkom ◽  
E Wilcots ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Large Scale ◽  
Rotation Curve ◽  
Neutral Hydrogen ◽  
Large Scale Structure ◽  
Scaling Relations ◽  
Angular Momentum Vector ◽  
Late Type ◽  
Spin Alignment ◽  
Momentum Vector

ABSTRACT We present neutral hydrogen (H i) and ionized hydrogen (H α) observations of 10 galaxies out to a redshift of 0.1. The H i observations are from the first epoch (178 h) of the COSMOS H i Large Extragalactic Survey (CHILES). Our sample is H i biased and consists of 10 late-type galaxies with H i masses that range from 1.8 × 107 M⊙ to 1.1 × 1010 M⊙. We find that although the majority of galaxies show irregularities in the morphology and kinematics, they generally follow the scaling relations found in larger samples. We find that the H i and H α velocities reach the flat part of the rotation curve. We identify the large-scale structure in the nearby CHILES volume using DisPerSE with the spectroscopic catalogue from SDSS. We explore the gaseous properties of the galaxies as a function of location in the cosmic web. We also compare the angular momentum vector (spin) of the galaxies to the orientation of the nearest cosmic web filament. Our results show that galaxy spins tend to be aligned with cosmic web filaments and show a hint of a transition mass associated with the spin angle alignment.

scholarly journals Two Conjectures of G.D. Birkhoff

1999 ◽  
Vol 172 ◽  
pp. 439-440
Author(s):  
Christopher K. Mccord ◽  
Kenneth R. Meyer
Keyword(s):  
Angular Momentum ◽  
Integral Manifold ◽  
Center Of Mass ◽  
Angular Momentum Vector ◽  
Momentum Vector ◽  
Algebraic Set ◽  
Special Values ◽  
Integral Manifolds ◽  
Energy Center ◽  
Three Body

The spatial (planar) three-body problem admits the ten (six) integrals of energy, center of mass, linear momentum and angular momentum. Fixing these integrals defines an eight (six) dimensional algebraic set called the integral manifold, 𝔐(c, h) (m(c, h)), which depends on the energy level h and the magnitude c of the angular momentum vector. The seven (five) dimensional reduced integral manifold, 𝔐R(c, h) (mR(c, h)), is the quotient space 𝔐(c, h)/SO2 (m(c, h)/SO2) where the SO2 action is rotation about the angular momentum vector. We want to determine how the geometry or topology of these sets depends on c and h. It turns out that there is one bifurcation parameter, ν = −c2h, and nme (six) special values of this parameter, νi, i = 1, …, 9.At each of the special values the geometric restrictions imposed by the integrals change, but one of these values, ν5, does not give rise to a change in the topology of the integral manifolds 𝔐(c, h) and 𝔐R(c, h). The other eight special values give rise to nine different topologically distinct cases. We give a complete description of the geometry of these sets along with their homology. These results confirm some conjectures and refutes several others.

scholarly journals Reconstructing large-scale structure with neutral hydrogen surveys

2019 ◽  
Vol 2019 (11) ◽  
pp. 023-023 ◽  
Author(s):  
Chirag Modi ◽  
Martin White ◽  
Anže Slosar ◽  
Emanuele Castorina
Keyword(s):  
Large Scale ◽  
Neutral Hydrogen ◽  
Large Scale Structure ◽  
Scale Structure

Impulsive formation control using orbital energy and angular momentum vector

2010 ◽  
Vol 67 (5-6) ◽  
pp. 613-622 ◽  
Author(s):  
Yoonhyuk Choi ◽  
Sunghoon Mok ◽  
Hyochoong Bang
Keyword(s):  
Angular Momentum ◽  
Formation Control ◽  
Orbital Energy ◽  
Angular Momentum Vector ◽  
Momentum Vector

scholarly journals Division I Working Group on “Precession and the Ecliptic”

2005 ◽  
Vol 1 (T26A) ◽  
pp. 67-67
Author(s):  
James L. Hilton ◽  
N. Capitaine ◽  
J. Chapront ◽  
J.M. Ferrandiz ◽  
A. Fienga ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Division I ◽  
General Assembly ◽  
Angular Momentum Vector ◽  
Inertial Reference Frame ◽  
Matrix Representations ◽  
Momentum Vector ◽  
Polynomial Coefficients ◽  
The Earth ◽  
The Mean

AbstractThe WG has conferred via email on the topics of providing a precession theory dynamically consistent with the IAU 2000A nutation theory and updating the expressions defining the ecliptic. The consensus of the WG is to recommend:(a) The terms lunisolar precession and planetary precession be replaced by precession of the equator and precession of the ecliptic, respectively.(b) The IAU adopt the P03 precession theory, of Capitaine et al (2003a, A& A 412, 567–586) for the precession of the equator (Eqs. 37) and the precession of the ecliptic (Eqs. 38); the same paper provides the polynomial developments for the P03 primary angles and a number of derived quantities for use in both the equinox based and celestial intermediate origin based paradigms.(c) The choice of precession parameters be left to the user.(d) The recommended polynomial coefficients for a number of precession angles are given in Table 1 of the WG report, including the P03 expressions set out in Tables 3–;5 of Capitaine et al (2005, A& A 432, 355–;367), and those of the alternative Fukushima (2003, AJ 126, 494–;534) parameterization; the corresponding matrix representations are given in equations 1, 6, 11, and 22 of the WG report.(e) The ecliptic pole should be explicitly defined by the mean orbital angular momentum vector of the Earth-Moon barycenter in an inertial reference frame, and this definition should be explicitly stated to avoid confusion with older definitions. The formal WG report will be submitted, shortly to Celest. Mech. for publication and their recommendations will be submitted at the next General Assembly for adoption by the IAU.

scholarly journals Explaining the density profile of self-gravitating systems by statistical mechanics

2015 ◽  
Vol 11 (A29B) ◽  
pp. 743-743
Author(s):  
Dong-Biao Kang
Keyword(s):  
Dark Matter ◽  
Angular Momentum ◽  
Radial Distribution ◽  
Density Profile ◽  
Large Scale ◽  
Rotation Curve ◽  
Dark Matter Halo ◽  
Stellar Disk ◽  
Exponential Law ◽  
Flat Rotation Curve

AbstractA self-gravitating system usually shows a quasi-universal density profile, such as the NFW profile of a simulated dark matter halo, the flat rotation curve of a spiral galaxy, the Sérsic profile of an elliptical galaxy, the King profile of a globular cluster and the exponential law of the stellar disk. It will be interesting if all of the above can be obtained from first principles. Based on the original work of White & Narayan (1987), we propose that if the self-bounded system is divided into infinite infinitesimal subsystems, the entropy of each subsystem can be maximized, but the whole system's gravity may just play the role of the wall, which may not increase the whole system's entropy St, and finally St may be the minimum among all of the locally maximized entropies (He & Kang 2010). For spherical systems with isotropic velocity dispersion, the form of the equation of state will be a hybrid of isothermal and adiabatic (Kang & He 2011). Hence this density profile can be approximated by a truncated isothermal sphere, which means that the total mass must be finite and our results can be consistent with observations (Kang & He 2011b). Our method requires that the mass and energy should be conserved, so we only compare our results with simulations of mild relaxation (i.e. the virial ratio is close to -1) of dissipationless collapse (Kang 2014), and the fitting also is well. The capacity can be calculated and is found not to be always negative as in previous works, and combining with calculations of the second order variation of the entropy, we find that the thermodynamical stability still can be true (Kang 2012) if the temperature tends to be zero. However, the cusp in the center of dark matter halos can not be explained, and more works will continue.The above work can be generalized to study the radial distribution of the disk (Kang 2015). The energy constraint automatically disappears in our variation, because angular momentum is much more important than energy for the disk-shape system. To simplify this issue, a toy model is taken: 2D gravity is adopted, then at large scale it will be consistent with a flat rotation curve; the bulge and the stellar disk are studied together. Then with constraints of mass and angular momentum, the calculated surface density can be consistent with the truncated, up-bended or standard exponential law. Therefore the radial distribution of the stellar disk may be determined by both the random and orbital motions of stars. In our fittings the central gravity is set to be nonzero to include the effect of asymmetric components.

Sign in / Sign up

Export Citation Format

Share Document