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J/MNRAS/396/1231    Astrophotometric catalogue of NGC 891    (Rejkuba+, 2009)

The stellar population content of the thick disc and halo of the Milky Way analogue NGC 891. Rejkuba M., Mouhcine M., Ibata R. <Mon. Not. R. Astron. Soc., 396, 1231-1246 (2009)> =2009MNRAS.396.1231R
ADC_Keywords: Galaxies, nearby ; Photometry, HST ; Morphology Keywords: galaxies: formation - galaxies: haloes - galaxies: individual: NGC 891 - galaxies: stellar content Abstract: We present deep VI images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope, covering three fields in the north-east side of the edge-on disc galaxy NGC 891. The observed fields span a wide range of galactocentric distances along the eastern minor axis, extending from the plane of the disc to 12kpc, and out to ∼25kpc along the major axis. The photometry of individual stars reaches ∼2.5mag below the tip of the red giant branch. We use the astrophotometric catalogue to probe the stellar content and metallicity distribution across the thick disc and spheroid of NGC 891. Description: Observations of three fields (H1, H2 and H3) along the eastern edge of NGC 891 disc have been taken in 2003 February with the wide field camera (WFC) of ACS as part of program GO-9414. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 67 18 The observing log table2.dat 93 376320 Astrophotometric catalogue
See also: B/hst : HST Archived Exposures Catalog (STScI, 2007) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 18 A18 --- Name Field name 22- 23 I2 h RAh Right ascension (J2000) 25- 26 I2 min RAm Right ascension (J2000) 28- 32 F5.2 s RAs Right ascension (J2000) 34 A1 --- DE- Declination sign (J2000) 35- 36 I2 deg DEd Declination (J2000) 38- 39 I2 arcmin DEm Declination (J2000) 41- 44 F4.1 arcsec DEs Declination (J2000) 46- 55 A10 "YYYY-MM-DD" Date Observation date 57- 61 A5 --- Filter Filter (F606W or F814W) 63- 67 A5 s ExpTime Exposure time
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 6 I6 --- ID Sequential number 8- 16 F9.6 deg RAdeg Right ascension in decimal degrees (J2000) 19- 27 F9.6 deg DEdeg Declination in decimal degrees (J2000) 29- 34 F6.3 mag Vmag V magnitude (1) 36- 40 F5.3 mag e_Vmag rms uncertainty on Vmag (1) 42- 47 F6.3 mag Imag I magnitude (1) 49- 53 F5.3 mag e_Imag rms uncertainty on Imag (1) 55- 58 F4.2 --- chi Chi value of the PSF fit (good if chi≤1.5) 60- 65 F6.1 --- S/N Signal-to-noise ratio 67- 72 F6.3 --- Sharp Sharpness parameter [-0.3/0.3 is good] (4) 74- 78 F5.3 --- Round Roundness parameter (4) 80- 84 F5.3 mag Crowd Crowding parameter (4) 86 I1 --- Type [1/2] Object type (2) 88- 89 I2 --- Field [1/32] Field (H1, H2, H3 or overlap 12 or 23) 91 I1 --- f_Vmag [0/7] Bad or saturated pixels in V (3) 93 I1 --- f_Imag [0/7] Bad or saturated pixels in I (3)
Note (1): Calibrated V and I-band magnitudes and the associated errors as computed by DOLPHOT, but multiplied by a factor of 1.6 to correct for the underestimated dolphot errors Note (2): Types 1,2 correspond to a stellar (point source) object: 1 = good star, 2 = star too faint for PSF determination. Note (3): These last flags give an indication of whether a given star had some bad or saturated pixels within the PSF fitting radius [see the DOLPHOT manual by Dolphin (2005, DOLPHOT User's Guide for details:]: 1 = photometry aperture extends off chip 2 = too many bad or saturated pixels 4 = saturated at center of star Note (4): DOLPHOT output parameters (from DOLPHOT User's Guide): * Sharpness is 0 for a perfect stellar fit, >0 if too sharp (e.g. a cosmic ray), <0 if too broad (e.g. a cluster or galaxy) * Roundness can be used to discriminate between extended objects and diffraction spikes * Crowding tells how much brighter the star would have been measured had nearby stars not been fit simultaneously. It is 0 for an isolated star.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Oct-2009
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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