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J/A+A/328/167       BV photometry in supergiant shell LMC4  (Braun+, 1997)

No stellar age gradient inside supergiant shell LMC4. Braun J.M., Bomans D.J., Will J.-M., De Boer K.S. <Astron. Astrophys. 328, 167 (1997)> =1997A&A...328..167B (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Photometry, UBV ; Photometry, CCD Keywords: stars: early-type - Hertzsprung-Russell (HR) diagram - stars: luminosity function, mass function - ISM: bubbles - ISM: individual objects: LMC 4 - Magellanic Clouds Abstract: The youngest stellar populations of a 'J'-shaped region inside the supergiant shell (SGS) LMC4 have been analysed with CCD photometry in B, V passbands. This region consists of 2 coherent strips, one from the east to the west reaching about 400pc across the OB superassociation LH 77 and another extending about 850pc from south to north. The standard photometric methods yield for each of the 25 CCD fields a colour-magnitude diagram (CMD) which is used for age determination of the youngest star population by isochrone fitting. The resultant ages lie in the range from 9Myr to 16Myr without correlation with the distance to the LMC 4 centre. We therefore conclude that there must have been one triggering event for star formation inside this large LMC SGS with a diameter of 1.4kpc. Description: The file table1.dat shows the entire photometry. It consists of 25 CCD fields, each taken at the ESO 0.91 m Dutch telescope in April, 1993. With 10min B and 5min V exposures it reaches down to V = 20-21mag (depending on seeing). The table structure is that of the published Table 1 plus additional information about right ascension and declination. Thus the announced Table 3 had been omitted (note that the entire MACS catalogue is also available electronically, as Cat. I/221). The file is a finding chart of the CCD fields made from four (i.e. 44, 45, 51, 52) mosaiced V charts of the LMC atlas of Hodge & Wright (1967, "The Large Magellanic Cloud", Smithsonian Press). This chart is a version of Fig. 3 with better quality (i.e. new labels, slightly larger view etc.) and additionally marked fields C1, C2, and C3 of a new (January 1999) B, V photometry which will soon be available (see the authors homepage). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 100 20812 Photometry of the 'J' area inside LMC 4 78 10410 Mosaic chart of the LMC4 area with the positions
See also: I/221 : The Magellanic Catalogue of Stars - MACS (Tucholke+ 1996) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 7 F7.4 --- FieldSeq *Field Sequence 9- 14 F6.1 pix xtotal X coordinate of total area 16- 21 F6.1 pix ytotal Y coordinate of total area 23- 27 F5.1 pix xfield X coordinate of respective CCD field 29- 33 F5.1 pix yfield Y coordinate of respective CCD field 35- 40 F6.3 mag Vmag V magnitude 42- 46 F5.3 mag e_Vmag *Total error in Vmag 48- 53 F6.3 mag B-V B-V colour 55- 59 F5.3 mag e_B-V *Total error in B-V 61- 66 F6.3 mag MV0 Absolute (intrinsic) V magnitude 68- 73 F6.3 mag (B-V)0 Intrinsic B-V colour 75- 76 I2 h RAh *Right Ascension J2000 (hours) 78- 79 I2 min RAm Right Ascension J2000 (minutes) 81- 86 F6.3 s RAs Right Ascension J2000 (seconds) 88 A1 --- DE- Declination J2000 (sign) 89- 90 I2 deg DEd *Declination J2000 (degrees) 92- 93 I2 arcmin DEm Declination J2000 (minutes) 95- 99 F5.2 arcsec DEs Declination J2000 (seconds)
Note on FieldSeq: Field Sequence is a floating point derived by field number (0-24) plus star sequence number (at most 4 digits) divided by 10000. The fields are marked in Fig. 3 included as regions (Nos a-e) and fields (Nos 0-24) not in SIMBAD Note on e_Vmag, e_B-V: Total errors including systematic and statistic errors (see paper). Note on RAh and DEd: The given coordinates are derived by cross identification with MACS stars. The mean derivation from the reference grid is 0.27s, 1.1" respectively.
Acknowledgements: Jochen M. Braun
(End) Jochen M. Braun [Stw., Univ. Bonn], Patricia Bauer [CDS] 10-Aug-1999
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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