J/A+A/345/521 BVRI photometry of NGC 2264 (Flaccomio+, 1999) ================================================================================ BVRI photometry of the star-forming region NGC 2264: the initial mass function and star-forming rate Flaccomio E., Micela G., Sciortino S., Favata F., Corbally C., Tomaney A. =1999A&A...345..521F (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, UBVRI Keywords: Galaxy: open clusters and associations: individual: NGC 2264 - stars: pre-main sequence - stars: late-type - stars: formation Abstract: The pre-main-sequence (PMS) population in the mass range between =~0.2 and =~3M_{sun}_ in southern part of the star-forming region NGC 2264 has been studied, determining both the Initial Mass Function in the region as well as the star-formation rates for different mass ranges. The sample is a composite one, derived through the union of samples obtained through different techniques and each suffering from different biases: previously known PMS stars in the region from the literature, photometrically-selected T Tauri candidates (from our own photometric data, discussed in detail in the present paper) and X-ray selected PMS candidates (discussed in detail in a companion paper) have been joined to form a sample which we show to be statistically complete (i.e. free from the biases which affect each of the parent samples) down to =~0.6M_{sun}_ (while being incomplete at lower masses). Individual masses and ages have been derived by placing the individual stars on evolutionary tracks, allowing us to derive both the IMF and the star formation rate. The Initial Mass Function thus derived for NGC 2264 shows evidence for a bimodal distribution of masses, with a break in the IMF at around 1M_{sun}_. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table3.dat 55 520 Catalog of CCD photometry table5.dat 106 141 Catalog of observed NGC 2264 members -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Sequential number 4 A1 --- n_Seq [+] + when present in table5.dat file 5 I1 --- uPhot [0/1] 1: Uncertain photometry 7- 8 I2 h RAh Right ascension (J2000) 10- 11 I2 min RAm Right ascension (J2000) 13- 16 F4.1 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign (J2000) 19- 20 I2 deg DEd Declination (J2000) 22- 23 I2 arcmin DEm Declination (J2000) 25- 28 F4.1 arcsec DEs Declination (J2000) 30- 34 F5.2 mag Vmag Visual magnitude 36- 40 F5.2 mag B-V B-V colour index 42- 46 F5.2 mag V-R ? V-R colour index 48- 52 F5.2 mag R-I ? R-I colour index -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Identification number 5 I1 --- uPhot [0/1] 1: uncertain photometry 7- 8 I2 h RAh Right ascension (J2000) 10- 11 I2 min RAm Right ascension (J2000) 13- 16 F4.1 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign (J2000) 19- 20 I2 deg DEd Declination (J2000) 22- 23 I2 arcmin DEm Declination (J2000) 25- 28 F4.1 arcsec DEs Declination (J2000) 30- 34 F5.2 mag Vmag Visual Magnitude 36- 40 F5.2 mag B-V B-V colour Index 42- 46 F5.2 mag V-R ? V-R colour Index 48- 52 F5.2 mag R-I ? R-I colour Index 54- 58 F5.2 [solLum] Log(Lbol) ? Bolometric Luminosity 60- 63 F4.2 [K] Log(Teff) ? Effective Temperature 65- 68 F4.2 solMass Mass ? Mass 70- 73 F4.2 [yr] Log(Age) ? Logarithm of Age 75- 77 A3 --- Memb Membership criteria (1) 79-106 A28 --- Ident Cross identifications (2) -------------------------------------------------------------------------------- Note (1): Membership criteria: c: this paper (see text); x: Flaccomio et al. (in prep.); h: Herbig (1954ApJ...119..483H), Marcy (1980AJ.....85..230M), Ogura (1984PASJ...36..139O) or Sung et al. (1997AJ....114.2644S) p: Vasilevskis et al. (1965AJ.....70..797V) with membership probabilities >50%. Note (2): A prefix, indicating the original catalog, is followed by the reference number used by the authors of the catalog. The prefixes stand for: W: Walker (1956ApJS....2..365W) V: Vasilevskis et al. (1965AJ.....70..797V) S: Sung et al. (1997AJ....114.2644S) O: Ogura (1984PASJ...36..139O) M: Marcy (1980AJ.....85..230M) H: Herbig (1954ApJ...119..483H) FX: Flaccomio et al. (in prep.) -------------------------------------------------------------------------------- Acknowledgements: Ettore Flaccomio ================================================================================ (End) Patricia Bauer [CDS] 27-Apr-1999