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J/A+A/488/211       Infrated photometry of NGC 1893           (Caramazza+, 2008)

Circumstellar Disks in the Outer Galaxy: the Star Forming Region NGC 1893. Caramazza M., Micela G., Prisinzano L., Rebull L., Sciortino S., Stauffer J.R. <Astron. Astrophys. 488, 211 (2008)> =2008A&A...488..211C
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, infrared Keywords: stars: pre-main sequence - stars: circumstellar matter - Galaxy: open cluster and association: individual: NGC 1893 - stars: formation Abstract: The independence of the star formation processes with respect to the environmental conditions is controversial. In particular it is not clear whether star formation in the outer Galaxy, where the environmental conditions are, theoretically, less conducive, occurs in the same way as in the inner Galaxy. We investigate the population of NGC 1893, a young cluster (∼3-4Myr) in the outer part of the Galaxy (galactic radius >11kpc) in order to explore the effects of environmental conditions on star forming regions. We present the infrared observations obtained with the IRAC camera on board of the Spitzer Space Telescope and analyze the color-color diagrams to establish the membership of stars with excesses. We also merge this information with that obtained from Chandra ACIS-I observations, in order to identify the Class III population. We find that the cluster is very rich, with 242 PMS Classical T-Tauri stars and 7 Class 0/I stars. Moreover we identify 110 Class III candidate cluster members in the ACIS-I field of view. We estimate a disk fraction for NGC 1893 of about 67%, similar to fraction calculated for nearby star forming regions of the same age. Although the environmental conditions are not favorable, star formation can clearly be very successful in the outer Galaxy, allowing creation of a very rich cluster like NGC 1893. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 125 15277 Coordinates and magnitudes of sources in our catalog table4.dat 48 818 Parameters of cluster members
See also: J/MNRAS/379/1237 : VIcJHK photometry of NGC1893 Halpha sources (Maheswar+ 2007) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 9 I1 h RAh Right ascension (J2000) 11- 12 I2 min RAm Right ascension (J2000) 14- 18 F5.2 s RAs Right ascension (J2000) 22 A1 --- DE- Declination sign (J2000) 23- 24 I2 deg DEd Declination (J2000 26- 27 I2 arcmin DEm Declination (J2000) 29- 33 F5.2 arcsec DEs Declination (J2000) 37- 41 F5.2 mag Kmag ? K magnitude 45- 48 F4.2 mag e_Kmag ? Error in K magnitude 52- 57 F6.3 mag [3.6] ? Magnitude at 3.6um 61- 65 F5.3 mag e_[3.6] ? Error in [3.6] magnitude 69- 74 F6.3 mag [4.5] ? Magnitude at 4.5um 78- 82 F5.3 mag e_[4.5] ? Error in [4.5] magnitude 86- 91 F6.3 mag [5.8] ? Magnitude at 5.8um 95- 99 F5.3 mag e_[5.8] ? Error in [5.8] magnitude 103-108 F6.3 mag [8.0] ? Magnitude at 8.0um 112-116 F5.3 mag e_[8.0] ? Error in [8.0] magnitude 120-125 F6.3 --- Sharp DAOPHOT Sharp parameter (1)
Note (1): the "sharp" parameter is close to zero for isolated stars; significantly negative for bad pixels and cosmic rays; significantly positive for blended or non-stellar objects.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 9- 13 F5.2 mag [3.6] Magnitude at 3.6um 17- 21 F5.2 mag [4.5] Magnitude at 4.5um 25- 29 F5.2 mag [5.8] ? Magnitude at 5.8um 33- 37 F5.2 mag [8.0] ? Magnitude at 8.0um 42 I1 --- Class [0/3]? T Tau Class flag (1) 47- 48 I2 --- Xray [-1/1] X-ray emission flag (2)
Note (1): Class flag as follows: 0 = Class 0/I Protostars 2 = Classical T-Tauri stars 3 = Weak-lined T-Tauri Note (2): X-ray flag as follows: -1 = Stars out of the ACIS field of view 1 = X-ray sources 0 = Stars without X-ray emission in the ACIS field of view
Acknowledgements: Marilena Caramazza, mcarama(at)
(End) Marilena Caramazza [INAF-OAPA, Italy], Patricia Vannier [CDS] 13-Jun-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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