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Related papers: Declining Rotation Curve and Brown Dwarf MACHOs

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We introduce a very simple model of a dark halo. It is a close relative of Hernquist's model, being generated by the same transformation but this time applied to the logarithmic potential rather than the point mass. The density is…

Astrophysics of Galaxies · Physics 2015-06-22 N. W. Evans , A. A. Williams

Disk-halo models of the Galaxy and LMC are constructed and used to analyse the microlensing data-set. Deflectors in the LMC bar, disk and halo provide an optical depth to microlensing of $\sim 2 \times 10^{-7}$. Deflectors in the Galactic…

Astrophysics · Physics 2016-06-08 N. W. Evans

One of the predictions of the standard CDM is that dark haloes have centrally divergent density profiles. An extensive body of rotation curve observations of dwarf and low surface brightness galaxies shows the dark haloes of those systems…

Astrophysics · Physics 2009-10-31 C. Firmani , E. D'Onghia , G. Chincarini , X. Hernandez , V. Avila-Reese

We present an extensive parameter survey to study the influence of halo mass profiles on the development of tidal tails in interacting disk galaxies. We model the galaxies using a fixed exponential disk with a central bulge and vary the…

Astrophysics · Physics 2009-10-31 John Dubinski , J. Christopher Mihos , Lars Hernquist

Rotation curves constrain a galaxy's underlying mass density profile, under the assumption that the observed rotation produces a centripetal force that exactly balances the inward force of gravity. However, most rotation curves are measured…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 J. J. Dalcanton , A. Stilp

We study the use of parallax microlensing to separate the effects of the mass function of dark massive halo objects (MHOs or `machos') on the one hand and their spatial distribution and kinematics on the other. This disentanglement is…

Astrophysics · Physics 2007-05-23 D. Markovic

We re-examine a deep {\it Hubble Space Telescope} pencil-beam search for red dwarfs, stars just massive enough to burn Hydrogen. The authors of this search (Bahcall, Flynn, Gould \& Kirhakos 1994) found that red dwarfs make up less than 6\%…

Astrophysics · Physics 2009-10-28 David S. Graff , Katherine Freese

We use a homogeneous sample of about 1100 rotation curves (RCs) and relative surface photometry to investigate (out to 2 optical radii and over 6 mag) the main mass structure properties of spirals. We confirm the strong dependence on…

Astrophysics · Physics 2015-06-24 M. Persic , P. Salucci , F. Stel

We present Halpha rotation curves for a sample of 15 dwarf and LSB galaxies. From these, we derive limits on the slopes of the central mass distributions. Assuming the density distributions of dark matter halos follow a power-law at small…

Astrophysics · Physics 2008-11-26 R. A. Swaters , B. F. Madore , F. C. van den Bosch , M. Balcells

We have compiled a new sample of 240 halo objects with accurate distance and radial velocity measurements, including globular clusters, satellite galaxies, field blue horizontal branch stars and red giant stars from the Spaghetti survey.…

We discuss the tight interconnection between microlensing optical depths, flattening of dark haloes and low-to-intermediate redshift baryonic census. By analysing plots of the microlensing optical depth as a function of galactic coordinates…

Astrophysics · Physics 2009-10-31 Srdjan Samurovic , Milan M. Cirkovic , Vesna Milosevic-Zdjelar

The microlensing experiments in the direction of the LMC seem to be indicating that about 60% of the dark matter in the Galactic halo is tied up in objects whose masses are about half the mass of the Sun. This mass is a natural one for old…

Astrophysics · Physics 2007-05-23 Harvey B. Richer

The dark matter distribution of the Milky Way remains among the major unsolved problems about our home galaxy. The masses of other spiral galaxies can be determined from their rotation curves through long-slit spectroscopy. But for the…

Astrophysics · Physics 2009-09-29 Peter M. Frinchaboy , Steven R. Majewski

Discoveries of extended rotation curves have suggested the presence of dark matter in spiral galaxy haloes. It has led to many studies that estimated the galaxy total mass, mostly by using the Navarro Frenk and White (NFW) density profile.…

Astrophysics of Galaxies · Physics 2021-10-13 Yongjun Jiao , Francois Hammer , Jianling Wang , Yanbin Yang

This paper addresses available constraints on mass models fitted to rotation curves. Mass models of disk galaxies have well-known degeneracies, that prevent a unique mass decomposition. The most notable is due to the unknown value of the…

Astrophysics · Physics 2009-11-10 Aaron A. Dutton , Stephane Courteau , Roelof de Jong , Claude Carignan

Halo stars orbit within the potential of the Milky Way and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends sensitively upon assumptions made on the density…

Astrophysics of Galaxies · Physics 2015-06-22 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

Using a large sample of Main Sequence stars with 7-D measurements supplied by Gaia and SDSS, we study the kinematic properties of the local (within ~10 kpc from the Sun) stellar halo. We demonstrate that the halo's velocity ellipsoid…

Astrophysics of Galaxies · Physics 2018-06-13 V. Belokurov , D. Erkal , N. W. Evans , S. E. Koposov , A. J. Deason

If the massive compact halo object (MACHO) fraction of the Galactic dark halo is f ~ 20% as suggested by some microlensing experiments, then about 1.2% of lensing events toward the Galactic bulge are due to MACHOs. For the 40% of these that…

Astrophysics · Physics 2009-11-10 Andrew Gould

The radial number density and flattening of the Milky Way's stellar halo is measured with $\mathrm{5351}$ metal-poor ([Fe/H]$<-1$) K giants from LAMOST DR3, using a nonparametric method which is model independent and largely avoids the…

We present a systematic analysis of the rotation curves of 187 galaxies with masses greater than 10^10 M_sol, with atomic gas masses from the GALEX Arecibo Sloan Survey (GASS), and with follow-up long-slit spectroscopy from the MMT. Our…

Astrophysics of Galaxies · Physics 2015-08-06 Guinevere Kauffmann , Mei-ling Huang , Sean Moran , Timothy Heckman