The MACHO Project: Limits on Planetary Mass Dark Matter in the Galactic Halo from Gravitational Microlensing | Zendy

C. Alcock | Zendy; R. A. Allsman | Zendy; D. R. Alves | Zendy; T. S. Axelrod | Zendy; A. C. Becker | Zendy; D. P. Bennett | Zendy; K. H. Cook | Zendy; K. C. Freeman | Zendy; K. Griest | Zendy; J. Guern | Zendy; M. J. Lehner | Zendy; S. L. Marshall | Zendy; B. A. Peterson | Zendy; M. R. Pratt | Zendy; Peter J. Quinn | Zendy; A. W. Rodgers | Zendy; C. W. Stubbs | Zendy; William J. Sutherland | Zendy

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The MACHO Project: Limits on Planetary Mass Dark Matter in the Galactic Halo from Gravitational Microlensing

Author(s) -

C. Alcock,

R. A. Allsman,

D. R. Alves,

T. S. Axelrod,

A. C. Becker,

D. P. Bennett,

K. H. Cook,

K. C. Freeman,

K. Griest,

J. Guern,

M. J. Lehner,

S. L. Marshall,

B. A. Peterson,

M. R. Pratt,

Peter J. Quinn,

A. W. Rodgers,

C. W. Stubbs,

William J. Sutherland

Publication year - 1996

Publication title -

the astrophysical journal

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 2.376

H-Index - 489

eISSN - 1538-4357

pISSN - 0004-637X

DOI - 10.1086/178005

Subject(s) - gravitational microlensing , physics , astrophysics , dark matter , large magellanic cloud , milky way , halo , galactic halo , dark matter halo , astronomy , massive compact halo object , gravitational lens , stars , galaxy , brown dwarf , redshift

The MACHO project has been monitoring about ten million stars in the LargeMagellanic Cloud in the search for gravitational microlensing events caused bymassive compact halo objects (Machos) in the halo of the Milky Way. In ourstandard analysis, we have searched this data set for well sampled, longduration microlensing lightcurves, detected several microlensing eventsconsistent with Machos in the 0.1 < m < 1.0 M_sun mass range, and set limits onthe abundance of objects with masses 1e-5 < m < 0.1 M_sun. In this paper, wepresent a different type of analysis involving the search for very short timescale brightenings of stars which is used to set strong limits on the abundanceof lower mass Machos. Our analysis of the first two years of data toward theLMC indicates that Machos with masses in the range 2.5e-7 < m < 5.2e-4 M_suncannot make up the entire mass of a standard spherical dark halo. Combiningthese results with those from the standard analysis, we find that the halo darkmatter may not be comprised of objects with masses 2.5e-7 < m < 8.1e-2 M_sun.Comment: Submitted to ApJ, 4/28/9

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