Based on observations made with VISTA at ESO under programme ID 179.B-2003.
The VMC survey – V. First results for classical Cepheids†
Article first published online: 3 JUL 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 424, Issue 3, pages 1807–1816, 11 August 2012
How to Cite
Ripepi, V., Moretti, M. I., Marconi, M., Clementini, G., Cioni, M.-R. L., Marquette, J. B., Girardi, L., Rubele, S., Groenewegen, M. A. T., de Grijs, R., Gibson, B. K., Oliveira, J. M., van Loon, J. Th. and Emerson, J. P. (2012), The VMC survey – V. First results for classical Cepheids. Monthly Notices of the Royal Astronomical Society, 424: 1807–1816. doi: 10.1111/j.1365-2966.2012.21274.x
Research fellow at the Alexander von Humboldt Foundation.
- Issue published online: 1 AUG 2012
- Article first published online: 3 JUL 2012
- Manuscript Accepted: 9 MAY 2012
- Manuscript Received: 5 MAY 2012
- Royal Astronomical Society
- University of Hertfordshire
- National Natural Science Foundation of China. Grant Number: 11073001
- Cambridge Astronomy Survey Unit
- VISTA Science Archive at Wide Field Astronomy Unit
- stars: variables: Cepheids;
- galaxies: distances and redshifts;
- Magellanic Clouds
The VISTA Magellanic Cloud (VMC; PI: M.-R. L. Cioni) survey is collecting deep Ks-band time series photometry of the pulsating variable stars hosted by the system formed by the two Magellanic Clouds (MCs) and the bridge connecting them. In this paper, we present the first results for classical Cepheids, from the VMC observations of two fields in the Large Magellanic Cloud (LMC), centred on the South Ecliptic Pole and the 30 Doradus star-forming regions, respectively. The VMC Ks-band light curves of the Cepheids are well sampled (12 epochs) and of excellent precision (typical errors of ∼0.01 mag). We were able to measure for the first time the Ks magnitude of the faintest classical Cepheids in the LMC (Ks ∼ 17.5 mag), which are mostly pulsating in the first overtone (FO) mode, and to obtain FO period–luminosity (PL), period–Wesenheit (PW) and period–luminosity–colour (PLC) relations, spanning the full period range from 0.25 to 6 d. Since the longest period Cepheid in our data set has a variability period of 23 d, we have complemented our sample with literature data for brighter F Cepheids. On this basis, we have built a PL relation in the Ks band that, for the first time, includes short-period – hence low-luminosity – pulsators, and spans the full range from 1.6 to 100 d in period.We also provide the first ever empirical PW and PLC relations using the (V − Ks) colour and time series Ks photometry. The very small dispersion (∼0.07 mag) of these relations makes them very well suited to study the three-dimensional geometry of the Magellanic system. The use of ‘direct’ (parallax- and Baade–Wesselink-based) distance measurements to both Galactic and LMC Cepheids allowed us to calibrate the zero-points of the PL, PW and PLC relations obtained in this paper, and in turn to estimate an absolute distance modulus of (m − M)0 = 18.46 ± 0.03 mag for the LMC. This result is in agreement with most of the latest literature determinations based on classical Cepheids.