J/A+A/462/599 JHKs photometry of LMC cluster Cepheids (Testa+, 2007)
IR photometry of Cepheids in the LMC clusters NGC 1866 and NGC 2031.
Testa V., Marconi M., Musella I., Ripepi V., Dallora M., Ferraro F.R.,
Mucciarelli A., Mateo M., Cote P.
<Astron. Astrophys. 462, 599 (2007)>
=2007A&A...462..599T 2007A&A...462..599T
ADC_Keywords: Magellanic Clouds ; Clusters, open ; Stars, variable ;
Photometry, infrared
Keywords: Cepheids - Magellanic Clouds -
globular clusters: individual: NGC 1866 -
globular clusters: individual: NGC 2031 - stars: distances
Abstract:
This work presents IR photometry for two young clusters known to
contain sizeable Cepheid populations: NGC 1866 and NGC 2031. The goal
is to determine light curves and period-luminosity (PL) relations in
the near-IR, to assess the similarity between cluster and field
pulsators, and to examine the predictive capability of current
pulsation models. The light curves are obtained from multiwavelength
broadband J,H,Ks photometry of Cepheids in both clusters, with periods
previously established from optical photometry. Mean magnitudes for
the Cepheids are used to construct period-luminosity (PL) relations in
the near-IR. The properties in the PL planes are compared with the
behavior of field Cepheids in the LMC and with the predictions of
recent pulsational models, both canonical and overluminous. Cluster
and field Cepheids are homogeneous and the inclusion of the cluster
Cepheids in the field sample extends the PL relation. The slope of the
PL relation is constant over the whole period range and does not show,
at least in the adopted IR bands, the break in slope at P∼10d reported
by some authors. A comparison with the predictions of pulsation models
allows an estimate for the distance moduli of NGC 1866 and NGC 2031.
The two clusters are found to lie at essentially the same distance.
Fitting of theoretical models to the data gives, for the K filter,
(m-M)0=18.62±0.10 if canonical models are used and
(m-M)0=18.42±0.10 if overluminous models are used.
Description:
Photometric tables for the clusters NGC 1866 and 2031 showing the mean
JHK magnitudes of the Cepheids variables studied in the paper and
their errors.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table23.dat 86 28 Mean IR magnitudes for Cepheids in NGC 1866 & NGC 2031
photom.dat 72 259 IR light curves for Cepheids in NGC 1866 & NGC 2031
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See also:
J/MNRAS/224/61 : NGC 6649 UBV photometry (Walker+ 1987)
J/AcA/49/543 : OGLE LMC + SMC Cepheids VI photometry (Pietrzynski+, 1999)
J/A+AS/145/365 : BVI photometry of NGC 7790 (Gupta+, 2000)
J/A+A/440/487 : Cepheids in the young LMC cluster NGC 1866 (Storm+, 2005)
J/MNRAS/370/1979 : Type II Cepheids in GC JHKs photometry (Matsunaga+, 2006)
Byte-by-byte Description of file: table23.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name (NGC 1866 or NGC 2031)
10- 16 A7 --- Name Cepheid Name
18 A1 --- n_Name [o] Overluminous model
20- 26 F7.5 d Per Period
30- 34 F5.2 mag Jmag Mean J magnitude
37- 40 F4.2 mag e_Jmag J magnitude error
43- 47 F5.2 mag Hmag Mean H magnitude
50- 53 F4.2 mag e_Hmag H magnitude error
56- 60 F5.2 mag Ksmag Mean Ks magnitude
63- 66 F4.2 mag e_Ksmag Ks magnitude error
68- 86 A19 --- SName Simbad Name
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name (NGC 1866 or NGC 2031)
10- 16 A7 --- Name Cepheid Name
18- 23 F6.3 mag Jmag ?=- J magnitude
26- 30 F5.3 mag e_Jmag ?=- J magnitude error
32- 37 F6.3 mag Hmag ?=- H magnitude
40- 44 F5.3 mag e_Hmag ?=- H magnitude error
46- 51 F6.3 mag Ksmag ?=- Ks magnitude
54- 58 F5.3 mag e_Ksmag ?=- Ks magnitude error
60- 72 F13.5 d JD Julian Date
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Acknowledgements:
Vincenzo Testa, testa(at)oa-roma.inaf.it
(End) Vincenzo Testa [INAF-OAR, Italy], Patricia Vannier [CDS] 23-Jan-2007