Testing modified Newtonian dynamic with Local Group spiral galaxies

AbstractChandra and XMM-Newton are revolutionizing our understanding of compact binaries in external galaxies, allowing us to study sources in detail in Local Group Galaxies and study populations in more distant systems. In M31 the X-ray luminosity function depends on the local stellar population in the sense that areas with active star formation have more high luminosity sources, and a higher overall source density (Kong. Di Stefano. Garcia, & Greiner 2003). This result is also true in galaxies outside the Local Group; starburst galaxies have flatter X-ray luminosity functions than do spiral galaxies which are in turn flatter than elliptical galaxies. These observational results suggest that the high end of the luminosity function in star forming regions is dominated by short-lived high mass X-ray binaries.In Chandra Cycle 2 we started a Large Project to survey a sample of 11 nearby (< 10Mpc) face-on spiral galaxies. We find that sources can be approximately classified on the basis of their X-ray color into low mass X-ray binaries, high mass X-ray binaries and supersoft sources. There is an especially interesting class of source that has X-ray colors softer (“redder”) than a typical low mass X-ray binary source, but not so extreme as supersoft sources. Most of these are probably X-ray bright supernova remnants, but some may be a new type of black hole accretor. Finally, when we construct a luminosity function of sources selecting only sources with low mass X-ray binary colors (removing soft sources) we find that there is a dip or break probably associated with the Eddington luminosity for a neutron star.

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Spectroscopic study of formation, evolution and interaction of M31 and M33 with star clusters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315007814 ◽

2014 ◽

Vol 10 (S312) ◽

pp. 201-202 ◽

Cited By ~ 1

Author(s):

Zhou Fan ◽

Yanbin Yang

Keyword(s):

Globular Clusters ◽

Stellar Population ◽

Local Group ◽

Spiral Galaxies ◽

Star Clusters ◽

Star Cluster ◽

Physical Parameters ◽

Cluster Systems ◽

Nearby Galaxies ◽

Formation And Evolution

AbstractThe recent studies show that the formation and evolution process of the nearby galaxies are still unclear. By using the Canada France Hawaii Telescope (CFHT) 3.6m telescope, the PanDAS shows complicated substructures (dwarf satellite galaxies, halo globular clusters, extended clusters, star streams, etc.) in the halo of M31 to ~150 kpc from the center of galaxy and M31-M33 interaction has been studied. In our work, we would like to investigate formation, evolution and interaction of M31 and M33, which are the nearest two spiral galaxies in Local Group. The star cluster systems of the two galaxies are good tracers to study the dynamics of the substructures and the interaction. Since 2010, the Xinglong 2.16m, Lijiang 2.4m and MMT 6.5m telescopes have been used for our spectroscopic observations. The radial velocities and Lick absorption-line indices can thus be measured with the spectroscopy and then ages, metallicities and masses of the star clusters can be fitted with the simple stellar population models. These parameters could be used as the input physical parameters for numerical simulations of M31-M33 interaction.

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A Comparison of Chemical Evolution between the Milky Way and M31 Galaxy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306006788 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 313-313

Author(s):

J. Yin ◽

J.L. Hou ◽

R.X. Chang ◽

S. Boissier ◽

N. Prantzos

Keyword(s):

Star Formation ◽

Chemical Evolution ◽

Milky Way ◽

Local Group ◽

Spiral Galaxies ◽

Star Formation History ◽

Milky Way Galaxy ◽

Andromeda Galaxy ◽

Formation History ◽

Formation And Evolution

Andromeda galaxy (M31,NGC224) is the biggest spiral in the Local Group. By studying the star formation history(SFH) and chemical evolution of M31, and comparing with the Milky Way Galaxy, we are able to understand more about the formation and evolution of spiral galaxies.

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Dark Matter Around the Local Group?

Symposium - International Astronomical Union ◽

10.1017/s007418090013712x ◽

1988 ◽

Vol 130 ◽

pp. 585-585

Author(s):

Edmond Giraud

Keyword(s):

Dark Matter ◽

Velocity Field ◽

Velocity Distribution ◽

Local Group ◽

Spiral Galaxies ◽

Small Distance ◽

Expansion Rate ◽

Fall Velocity ◽

Hubble Expansion ◽

Local Value

The Hubble expansion rate measured in the short distance scale varies from 70–75 to 90 km s−1 Mpc−1 as the kinematic distance (corrected for in fall velocity toward Virgo) increases from Dv = 200–400 km s−1 to Dv ∼ 1300 km s−1. It should be observed in the long scale as well (starting from a lower value), if the same methods were used in the same way. The Malmquist bias for spiral galaxies in the range Dv ≤ 1300 km s−1 is very small or null. The velocity distribution of galaxies in the nearest groups compared with models of various rms velocity dispersions, suggests that at small distance, dispersions of 100 km s−1 or more do not fit the observations. The effect of the deceleration due to the mass of the Local Group on the very nearby velocity field is negligible beyond 2.5–3 Mpc. The low local value of Ho extends approximately over ∼ 6–7 Mpc.

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The Formation Chronology of Local Group Spiral Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900223401 ◽

2002 ◽

Vol 207 ◽

pp. 73-82

Author(s):

Ata Sarajedini

Keyword(s):

Globular Clusters ◽

Milky Way ◽

Local Group ◽

Spiral Galaxies ◽

Dwarf Galaxy ◽

Additional Parameter ◽

Horizontal Branch ◽

The Galaxy ◽

Metal Abundance ◽

Cluster Age

The ‘Second Parameter Effect’ (2ndPE) has long been recognized as an important probe into the formation of spiral galaxies. The concept that the horizontal branch morphologies of globular clusters are primarily affected by metal abundance in the inner halo (RGC<8 kpc) of the Galaxy but require an additional parameter (probably cluster age) to explain their behavior in the outer halo (RGC > 8 kpc), suggests that the former experienced a rapid monotonic collapse while the latter underwent a slower chaotic formation scenario. As such, in the Milky Way, the so-called second parameter boundary is located at 8 kpc. We find that, in the other Local Group spirals — M31 and M33 — this boundary lies at ∼40 kpc and ∼0 kpc, respectively. We therefore speculate that the boundary delimiting rapid monotonic halo collapse from the chaotic accretion of dwarf galaxy fragments is inversely related to the mass of the spiral galaxy.

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Dark matter in the local group of galaxies

International Journal of Modern Physics D ◽

10.1142/s0218271817500699 ◽

2017 ◽

Vol 26 (07) ◽

pp. 1750069 ◽

Cited By ~ 4

Author(s):

P. D. Morley ◽

D. J. Buettner

Keyword(s):

Monte Carlo ◽

Dark Matter ◽

Milky Way ◽

Local Group ◽

Spiral Galaxies ◽

Dark Matter Candidate ◽

Approximate Location ◽

Neutrino Flavor ◽

Degenerate Neutrino ◽

Katrin Experiment

We describe the neutrino flavor ([Formula: see text], [Formula: see text], [Formula: see text]) masses as [Formula: see text] [Formula: see text] with [Formula: see text] and probably [Formula: see text]. The quantity [Formula: see text] is the degenerate neutrino mass. Because neutrino flavor is not a quantum number, this degenerate mass appears in the neutrino equation-of-state [P. D. Morley and D. J. Buettner, Int. J. Mod. Phys. D (2014), doi:10.1142/s0218271815500042.]. We apply a Monte Carlo computational physics technique to the Local Group (LG) of galaxies to determine an approximate location for a Dark Matter embedding Condensed Neutrino Object (CNO) [P. D. Morley and D. J. Buettner, Int. J. Mod. Phys. D (2016), doi:10.1142/s0218271816500899.]. The calculation is based on the rotational properties of the only spiral galaxies within the LG: M31, M33 and the Milky Way. CNOs could be the Dark Matter everyone is looking for and we estimate the CNO embedding the LG to have a mass 5.17[Formula: see text] M[Formula: see text] and a radius 1.316 Mpc, with the estimated value of [Formula: see text] eV[Formula: see text]/c2. The up-coming KATRIN experiment [https://www.katrin.kit.edu.] will either be the definitive result or eliminate condensed neutrinos as a Dark Matter candidate.

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Spiral Galaxies and the Peculiar Velocity Field

Symposium - International Astronomical Union ◽

10.1017/s007418090011006x ◽

1996 ◽

Vol 168 ◽

pp. 183-191 ◽

Cited By ~ 2

Author(s):

Riccardo Giovanelli ◽

Martha P. Haynes ◽

Pierre Chamaraux ◽

Luiz N. Da Costa ◽

Wolfram Freudling ◽

...

Keyword(s):

Velocity Field ◽

Reference Frame ◽

Large Scale ◽

Local Group ◽

Spiral Galaxies ◽

Density Parameter ◽

Compelling Evidence ◽

Homogeneous Sample ◽

Peculiar Velocity ◽

Peculiar Velocities

We report results of a redshift-independent distance measurement survey that extends to all sky and out to a redshift of approximately 7500 km s−1. Tully–Fisher (TF) distances for a homogeneous sample of 1600 late spiral galaxies are used to analyze the peculiar velocity field. We find large peculiar velocities in the neighborhood of superclusters, such as Perseus–Pisces (PP) and Hydra–Centaurus, but the main clusters embedded in those regions appear to be virtually at rest in the CMB reference frame. We find no compelling evidence for large-scale bulk flows, whereby the Local Group, Hydra–Cen and PP would share a motion of several hundred km s−1with respect to the CMB. Denser sampling in the PP region allows a clear detection of infall and backflow motions, which can be used to map the mass distribution in the supercluster and to obtain an estimate of the cosmological density parameter.

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Spiral Galaxies, Elliptical Galaxies and the Large-Scale Velocity Field Within 3500 km/s of the Local Group

Symposium - International Astronomical Union ◽

10.1017/s0074180900135995 ◽

1988 ◽

Vol 130 ◽

pp. 177-180

Author(s):

David Burstein ◽

Roger L. Davies ◽

Alan Dressler ◽

S.M. Faber ◽

Donald Lynden-Bell ◽

...

Keyword(s):

Velocity Field ◽

Mass Concentration ◽

Large Scale ◽

Field Model ◽

Local Group ◽

Spiral Galaxies ◽

Independent Sets ◽

Elliptical Galaxies ◽

Substantial Agreement ◽

Model Predictions

The peculiar motions for spiral galaxies and elliptical galaxies within V = 3500 km/s are compared to the model predictions of the mass concentration (MC) velocity field model of Lynden-Bell et al. The large-scale motions defined by over 600 galaxies from three independent sets of data (Aaronson et al.; de Vaucouleurs and Peters and elliptical galaxies) are in substantial agreement with this model.

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