PROBING THE MASS FRACTION OF MACHOS IN EXTRAGALACTIC HALOS

Authors
Citation
R. Perna et A. Loeb, PROBING THE MASS FRACTION OF MACHOS IN EXTRAGALACTIC HALOS, The Astrophysical journal, 493(2), 1998, pp. 523-528
Citations number
30
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
493
Issue
2
Year of publication
1998
Part
1
Pages
523 - 528
Database
ISI
SICI code
0004-637X(1998)493:2<523:PTMFOM>2.0.ZU;2-K
Abstract
Current microlensing searches calibrate the mass fraction of the Milky Way halo that is in the form of massive astrophysical compact halo ob jects (MACHOs). We show that surveys like the Sloan Digital Sky Survey (SDSS) can probe the same quantity in halos of distant galaxies. Micr olensing of background quasars by MACHOs in intervening galaxies would distort the equivalent width distribution of the quasar emission line s by an amplitude that depends on the projected quasar-galaxy separati on. For a statistical sample of similar to 10(5) quasars as expected i n the SDSS, this distortion is detectable at the greater than or simil ar to 2 sigma level out to a quasar-galaxy impact parameter of several tens of kpc, as long as extragalactic halos are made of MACHOs. Detec tion of this signal would test whether the MACHO fraction inferred for the Milky Way halo is typical of other galaxies.