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Related papers: Is the galactic halo baryonic?

200 papers

In the context of this paper, microlenses present as oblate clusters of dark matter structures called massive astrophysical compact halo object(MACHO) in the galactic halo are considered. The NFW density profile [1] is derived from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Tabib Rayed Hossain , Prabir Kumar Haldar , Mehedi Kalam

We propose the existence of ultracompact minihalos as a new type of massive compact halo object (MACHO) and suggest an observational test to discover them. These new MACHOs are a powerful probe into the nature of dark matter and physics in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Ricotti , A. Gould

The recent detections of a large population of faint submillimetre sources, an excess halo gamma-ray background, and the extreme scattering events observed for extragalactic radio sources have been explained as being due to baryonic dark…

Astrophysics · Physics 2009-11-07 A. J. Drake , K. H. Cook

Gas in the interstellar matter is generally organized in filamentary structures, which may be also relevant for a complementary explanation of the dark matter in the Galactic halo. We examine the possibility that such structures may act as…

Astrophysics · Physics 2009-11-10 V. Bozza , L. Mancini

The simplest interpretation of the microlensing events towards the Large Magellanic Cloud detected by the MACHO and EROS collaborations is that about one third of the halo of our own Milky Way galaxy exists in the form of objects of around…

Astrophysics · Physics 2009-10-30 N. W. Evans , G. Gyuk , M. S. Turner , J. J. Binney

For almost twenty years models of the Galaxy have included a dark halo responsible for supporting a substantial fraction of the local rotation velocity and a flat rotation curve at large distances. Estimates of the local halo density range…

Astrophysics · Physics 2011-09-29 E. Gates , G. Gyuk , M. Turner

Under the assumption that the Milky Way's dark halo consists of primordial black hole MACHOs (PBHMACHOs), the mass density of the halo can be measured by the low frequency gravitational waves ($10^{-3} Hz \siml \nu_{gw} \siml 10^{-1}$ Hz)…

Astrophysics · Physics 2009-10-31 Kunihito Ioka , Takahiro Tanaka , Takashi Nakamura

A population of discrete HI clouds in the halo of the inner Galaxy has been discovered in 21cm observations made with the Green Bank Telescope. The halo clouds are seen up to 1.5 kpc from the Galactic plane at many longitudes. Their…

Astrophysics · Physics 2009-11-07 Felix J. Lockman

It has been revealed using microlensing that a considerable part, possibly more than half, of the dark matter in the halo of our Galaxy consists of objects with a mass spectrum ranging from 0.05 to 0.8 of the solar mass. What is the nature…

Astrophysics · Physics 2007-05-23 A. V. Gurevich , K. P. Zybin , V. A. Sirota

A significant fraction of non-baryonic or baryonic dark matter in galactic halos may consist of MASsive Compact Objects (MASCOs) with mass M=10^{1-4}M_{sun}. Possible candidates for such compact objects include primordial black holes or…

Astrophysics · Physics 2009-11-07 Kaiki Taro Inoue , Masashi Chiba

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

All previous attempts to understand the microlensing results towards the Large Magellanic Cloud (LMC) have assumed homogeneous present day mass functions (PDMFs) for the lensing populations. Here, we present an investigation into the…

Astrophysics · Physics 2009-10-30 E. Kerins , N. W. Evans

Recently obtained kinematic data has shown that the Large Magellanic Cloud (LMC) possesses an old stellar halo. In order to further characterize the properties of this halo, parametric King models are fit to the surface density of RR Lyrae…

Astrophysics · Physics 2009-11-10 David R. Alves

The MACHO project carries out regular photometric monitoring of millions of stars in the Magellanic Clouds and Galactic Bulge, to search for very rare gravitational microlensing events due to compact objects in the galactic halo and disk. A…

We report on our search for microlensing towards the Large Magellanic Cloud (LMC). Analysis of 5.7 years of photometry on 11.9 million stars in the LMC reveals 13 - 17 microlensing events. This is significantly more than the $\sim$ 2 to 4…

We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…

Baryons constitute about 4% of our universe, but most of them are missing and we do not know where and in what form they are hidden. This constitute the so-called missing baryon problem. A possibility is that part of these baryons are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 F. De Paolis , G. Ingrosso , A. A. Nucita , D. Vetrugno , V. G. Gurzadyan , A. L. Kashin , H. G. Khachatryan , S. Mirzoyan , Ph. Jetzer , A. Qadir

The expected microlensing events of the LMC by the MACHOs of the LMC itself are calculated and compared with analogue events by objects in the Galactic halo. The LMC matter distribution is modelled by a spherical halo and an exponential…

Astrophysics · Physics 2009-10-22 Xiang-Ping Wu

If the halo of the lensing galaxy 0957+561 is made of massive compact objects (MACHOs), they must affect the lightcurves of the quasar images Q0957+561 A and B differently. We search for this microlensing effect in the double quasar by…

In the self--lensing framework, we estimate the modal values of the mass of the gravitational lenses found by the MACHO collaboration towards the Large Magellanic Cloud (LMC). Our results suggest that only the events located near the center…

Astrophysics · Physics 2011-10-18 L. Mancini , S. Calchi Novati , Ph. Jetzer , G. Scarpetta