Bulge microlensing optical depth from EROS 2 observations

被引：75

作者：

Afonso, C ^{[1
]}

Albert, JN

Alard, C

Andersen, J

Ansari, R

Aubourg, É

Bareyre, P

Bauer, F

Beaulieu, JP

Blanc, G

Bouquet, A

Char, S

Charlot, X

Couchot, F

Coutures, C

Derue, F

Ferlet, R

Fouqué, P

Glicenstein, JF

Goldman, B

Gould, A

Graff, D

Gros, M

Haissinski, J

Hamadache, C

Hamilton, JC

Hardin, D

de Kat, J

Kim, A

Lasserre, T

LeGuillou, L

Lesquoy, É

Loup, C

Magneville, C

Mansoux, B

Marquette, JB

Maurice, É

Maury, A

Milsztajn, A

Moniez, M

Palanque-Delabrouille, N

Perdereau, O

Prévot, L

Regnault, N

Rich, J

Spiro, M

Tisserand, P

Vidal-Madjar, A

Vigroux, L

Zylberajch, S

机构：

[1] Ctr Etud Saclay, CEA, DSM, F-91191 Gif Sur Yvette, France

[2] Univ Paris 11, Lab Accelerateur Lineaire, IN2P3, CNRS, F-91405 Orsay, France

[3] INSU CNRS, DASGAL, F-75014 Paris, France

[4] Observ Marseille, F-13248 Marseille 04, France

[5] Coll France, IN2P3, CNRS, F-75231 Paris, France

[6] CNRS, Inst Astrophys Paris, INSU, F-75014 Paris, France

[7] Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark

[8] Univ La Serena, Fac Ciencias, Dept Fis, La Serena, Chile

[9] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA

[10] Observ Paris, LESIA, F-92195 Meudon, France

[11] New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA

[12] European So Observ, Santiago 19, Chile

[13] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA

来源：

ASTRONOMY & ASTROPHYSICS | 2003年 / 404卷 / 01期

关键词：

Galaxy : stellar content; Galaxy : structure; gravitational lensing;

D O I：

10.1051/0004-6361:20030307

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present a measurement of the microlensing optical depth toward the Galactic bulge based on the analysis of 15 contiguous 1 deg(2) fields centered on (l = 2.degrees5, b = -4.degrees0) and containing N-* = 1.42 x 10(6) clump-giant stars ( belonging to the extended clump area) monitored during almost three bulge seasons by EROS (Experience de Recherche d'Objets Sombres). We find tau(bulge) = 0.94 +/- 0.29 x 10(-6) averaged over all fields, based on 16 microlensing events with clump giants as sources. This value is substantially below several other determinations by the MACHO and OGLE groups and is more in agreement with what is expected from axisymmetric and non-axisymmetric bulge models.

引用

页码：145 / 156

页数：12

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