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J/A+A/615/A96       VI photometry in 3 dwarf galaxies           (Mueller+, 2018)

Distances from the tip of the red giant branch to the dwarf galaxies dw1335-29 and dw1340-30 in the Centaurus group. Mueller O., Rejkuba M., Jerjen H. <Astron. Astrophys. 615, A96 (2018)> =2018A&A...615A..96M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Photometry, UBVRI Keywords: galaxies: distances and redshifts - galaxies: dwarf - galaxies: clusters: individual: Centaurus group - galaxies: photometry Abstract: The abundance and spatial distribution of dwarf galaxies are excellent empirical benchmarks against which to test models of structure formation on small scales. The nearby Centaurus group, with its two subgroups centered on Cen A and M 83, stands out as an important alternative to the Local Group for scrutinizing cosmological model predictions in a group of galaxies context. We have obtained deep optical images of three recently discovered M 83 satellite galaxy candidates with the FORS2 instrument mounted on the Very Large Telescope. We aim to confirm their group membership and study their stellar population. Deep V I-band photometry was used to resolve the brightest stars in our targets. Artificial star tests are performed to estimate the completeness and uncertainties of the photometry. The color-magnitude diagrams reveal the red giant branch (RGB) stars, allowing us to use the Sobel edge detection method to measure the magnitude of the RGB tip and thus derive distances and group membership for our targets. The mean metallicity of the dwarf galaxies were further determined by fitting BASTI model isochrones to the mean RGB locus. Description: Our targets were the three dwarf galaxy candidates dw1325-33, dw1335-29, and dw1340-30, a subsample from the 16 candidates found by our team in the M 83 subgroup (Mueller et al., 2015A&A...583A..79M). In the left column of Fig. 1 we show the discovery images observed with the wide-field Dark Energy Camera mounted at the prime focus of the Blanco 4-m telescope at CTIO. The presented tables in like .raw format are standard matched photometry files produced by the standalone version of DAOPHOT2/DAOMASTER (just take-off the # in the first lines). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 71 8 Observation summary for the three dwarf galaxy candidates 1325-301.dat 79 1955 dw1325-30 VI chip 1 photometric catalog 1335-291.dat 79 2624 dw1335-29 VI chip 1 photometric catalog 1335-292.dat 79 1578 dw1335-29 VI chip 2 photometric catalog 1340-301.dat 79 2618 dw1340-30 VI chip 1 photometric catalog 1340-302.dat 79 2224 dw1340-30 VI chip 2 photometric catalog
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Name Galaxy name 11- 12 I2 h RAh Right ascension (J2000) 14- 15 I2 min RAm Right ascension (J2000) 17- 18 I2 s RAs Right ascension (J2000) 20 A1 --- DE- Declination sign (J2000) 21- 22 I2 deg DEd Declination (J2000) 24- 25 I2 arcmin DEm Declination (J2000) 27- 28 I2 arcsec DEs Declination (J2000) 30- 43 A14 --- Date Observing date 45- 49 A5 --- Inst Instrument 51- 56 A6 s TExp Exposure time 58 A1 --- Filter [VI] Filter used for the observation 60- 63 F4.2 --- Airmass Mean airmass during the observation 65- 71 A7 arcsec Qimg Average image quality measured on images
Byte-by-byte Description of file (# headlines): 1325-30?.dat 1335-29?.dat 1340-30?.dat
Bytes Format Units Label Explanations
1- 7 I7 --- ID Star identification number 9- 16 F8.3 pix Xpos X position on the cropped chip (1) 19- 25 F7.3 pix Ypos Y position on the cropped chip (1) 28- 34 F7.4 mag Vmag ?=99.9999 V band magnitude with zeropoint=25mag 38- 43 F6.4 mag e_Vmag ?=9.9999 V band magnitude error 46- 52 F7.4 mag Imag ?=99.9999 I band magnitude with zeropoint=25mag 56- 61 F6.4 mag e_Imag ?=9.9999 I band magnitude error 64- 70 F7.4 --- Chi ?=99.9999 CHI value 73- 79 F7.4 --- Sharp ?=9.9999 Sharpness value
Note (1): The cropping was performed with IRAFs imcopy command with X=200:1800, Y=10:960 on Chip 1 and X=200:1800, Y=320:1020 on Chip 2. 1 pix = 0.25".
Acknowledgements: Olivier Mueller, oliver89.mueller(at)unibas.ch
(End) Patricia Vannier [CDS] 27-Jul-2018
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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