ON THE RELATIVE DISTANCES OF ω CENTAURI AND 47 TUCANAE

被引：40

作者：

Bono, G. ^{[1
,2
]}

Stetson, P. B. ^{[3
]}

Sanna, N. ^{[1
,2
]}

Piersimoni, A. ^{[4
]}

Freyhammer, L. M. ^{[5
]}

Bouzid, Y. ^{[6
]}

Buonanno, R. ^{[2
]}

Calamida, A. ^{[1
]}

Caputo, F. ^{[1
]}

Corsi, C. E. ^{[1
]}

Di Cecco, A. ^{[1
,2
]}

Dall'Ora, M. ^{[7
]}

Ferraro, I. ^{[1
]}

Iannicola, G. ^{[1
]}

Monelli, M. ^{[8
]}

Nonino, M. ^{[9
]}

Pulone, L. ^{[1
]}

Sterken, C. ^{[6
]}

Storm, J. ^{[10
]}

Tuvikene, T. ^{[6
]}

Walker, A. R. ^{[11
]}

机构：

[1] INAF OAR, Rome, Italy

[2] UniToV, Dipartimento Fis, I-00133 Rome, Italy

[3] NRC, DAO HIA, Victoria, BC V9E 2E7, Canada

[4] INAF OACTe, I-64100 Teramo, Italy

[5] Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England

[6] VUB, B-1050 Brussels, Belgium

[7] INAF OACN, I-80131 Naples, Italy

[8] IAC, E-38200 San Cristobal la Laguna, Spain

[9] INAF OAT, I-40131 Trieste, Italy

[10] AIP, D-14482 Potsdam, Germany

[11] CTIAO NOAO, La Serena, Chile

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2008年 / 686卷 / 02期

关键词：

globular clusters: general; globular clusters: individual (omega Centauri; 47; Tucanae);

D O I：

10.1086/593013

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present precise optical and near-infrared ground-based photometry of two globular clusters (GCs): omega Cen and 47 Tuc. These photometric catalogs are unbiased in the red giant branch (RGB) region close to the tip. We provide new estimates of the RGB tip (TRGB) magnitudes-m(1)(TRGB) = 9.84 +/- 0.05, omega Cen; m(1)(TRGB) = 9.46 +/- 0.06, 47 Tuc-and use these to determine the relative distances of the two GCs. We find that distance ratios based on different calibrations of the TRGB, the RR Lyrae stars, and kinematic distances agree with each other within 1 sigma. Absolute TRGB and RR Lyrae distance moduli agree within 0.10-0.15 mag, while absolute kinematic distance moduli are 0.2-0.3 mag smaller. Absolute distances to 47 Tuc based on the zero-age horizontal branch and on the white dwarf fitting agree within 0.1 mag, but they are 0.1-0.3 mag smaller than TRGB and RR Lyrae distances.

引用

页码：L87 / L90

页数：4

共 42 条

[1] The calibration of the RGB tip as a standard candle - Extension to near infrared colors and higher metallicity [J].