J/MNRAS/341/805 UBVI CCD photometry of Cep OB3b (Pozzo+, 2003)
The discovery of low-mass pre-main-sequence stars in Cepheus OB3b.
Pozzo M., Naylor T., Jeffries R.D., Drew J.E.
<Mon. Not. R. Astron. Soc., 341, 805-822 (2003)>
=2003MNRAS.341..805P 2003MNRAS.341..805P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI
Keywords: accretion, accretion discs - techniques: radial velocities -
stars: formation - stars: late-type - stars: pre-main-sequence -
open clusters and associations: individual: Cepheus OB3
Abstract:
We report the discovery of a low-mass pre-main-sequence (PMS) stellar
population in the younger subgroup of the Cepheus OB3 association,
Cep OB3b, using UBVI CCD photometry and follow-up spectroscopy. The
optical survey covers approximately 1300arcmin2 on the sky and gives
a global photometric and astrometric catalogue for more than 7000
objects. The location of a PMS population is well defined in a V
versus (V-I) colour-magnitude diagram.
Description:
The UBVI CCD images were taken on the nights of 1997 August 10/11 and
11/12, with the 2.5-m Isaac Newton Telescope (INT), La Palma, Canary
Islands, Spain, equipped with the Wide Field Camera (WFC) and an array
of four Loral CCDs. Data were taken using filters U (RGO), B (Harris),
V (Harris) and I (RGO INT-WFC).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 119 13657 Photometric catalogue
flags.dat 84 18 Flags
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 F4.2 --- Field Field and CCD number (1)
6- 9 I4 --- Star Star number in the field
12- 13 I2 h RAh Right ascension (J2000.0)
15- 16 I2 min RAm Right ascension (J2000.0)
18- 23 F6.3 s RAs [0/60] Right ascension (J2000.0)
25 A1 --- DE- Declination sign (J2000.0)
26- 27 I2 deg DEd Declination (J2000.0)
29- 30 I2 arcmin DEm Declination (J2000.0)
32- 36 F5.2 arcsec DEs [0/60] Declination (J2000.0)
38- 45 F8.3 pix Xpos X position in the CCD image
47- 54 F8.3 pix Ypos Y position in the CCD image
56- 61 F6.3 mag Vmag ? V magnitude
62 A1 --- n_Vmag [I] I for +Inf
64- 68 F5.3 mag e_Vmag rms uncertainty on Vmag
70- 71 A2 --- f_Vmag Flag on Vmag, in flags. dat file
73- 78 F6.3 mag B-V B-V colour index
80- 84 F5.3 mag e_B-V rms uncertainty on B-V
86- 87 A2 --- f_B-V Flag on B-V colour, in flags.dat file
89- 94 F6.3 mag V-I V-I colour index
96-100 F5.3 mag e_V-I rms uncertainty on V-I
102-103 A2 --- f_V-I Flag on V-I colour, in flags.dat file
105-110 F6.3 mag U-B U-B colour index
112-116 F5.3 mag e_U-B rms uncertainty on U-B
118-119 A2 --- f_U-B Flag on U-B colour, in flags.dat file
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Note (1): The number before the decimal place is the field number,
the one after is the CCD number.
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Byte-by-byte Description of file: flags.dat
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Bytes Format Units Label Explanations
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1 A1 --- Flag Flag code (1)
3- 49 A47 --- Explain Flag meaning
51- 75 A25 --- Algorithm Algorithm used
77- 82 A6 --- Type Type (Strong or Weak)
84 I1 --- Fno ? Flag number for the older versions of
the software
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Note (1): If a star is flagged as having negative counts (M),
the magnitude is replaced with the uncertainty in flux converted into
magnitudes. Thus magnitudes for objects flagged M should be treated as
bright (i.e. lower) limits. It also means that colours which are
quoted for these objects are limits.
For example a flag of MO in the B-V colour, means that the B magnitude
is a lower limit, so B-V is a lower limit. The uncertainty becomes
meaningless, unless you want the description for real aficionados...
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History:
Copied at http://www.astro.ex.ac.uk/people/timn/Catalogues/PNJD2003/
(End) Patricia Vannier [CDS] 05-Apr-2007