J/AJ/112/601 J/AJ/112/601 UV photometry in M79 R S Hill K -P Cheng E P Smith P M N Hintzen R C Bohlin R W OConnell M S Roberts A M Smith T P Stecher Astron. J. 112 601 1996 1996AJ....112..601H Clusters, globular Photometry, ultraviolet Ultraviolet photometry is presented for the globular cluster M79 (NGC 1904) according to the final calibration of the images obtained on the Astro-1 Spacelab mission by the Ultraviolet Imaging Telescope. These results include both point-source and surface photometry at 152nm and 249nm. An ultraviolet color-magnitude (C-M) diagram in these bandpasses is presented. The detected stars are also cross-matched with the ground-based photometry of Ferraro et al. (1992MNRAS.256..391F) to produce C-M and two-color diagrams covering a 4000A span in wavelength. The observed horizontal branch (HB) is compared with stellar interior models of the zero-age HB (ZAHB). Many stars are found in post-HB evolutionary stages more luminous than the ZAHB. The distribution of stars along the ZAHB in m152-m249 color is investigated, and an indication of possible bimodality is found. The relative population of the blue HB tail may vary with radius for radii greater than 1'. Ultraviolet surface brightness and color-index profiles are presented. The previously reported central gradient in the m152-V color index is confirmed, and a faint diffuse component is detected outside a radius of 40" in the 152nm band. Two possible causes of the central color gradient are discussed: mass segregation, and the destruction of red giant envelopes by enhanced mass loss in the cluster core.

ASTRO 1/UIT

Star Ordinal number of UIT-detected star in M79 --- Note Table note mark Table note mark "g": Star 94=UIT-1 and star 76 = UIT-2 as discussed in Paper I (Hill, R. S. et al. 1992ApJ...395L..17H). Stars 26, 67, 100, 109, and 127 are in the area observed by F92 but have no F92-HB match with B-V<0.4. Stars 111, 120, and 122 are ambiguously matched by two or more F92 (1992MNRAS.256..391F) HB stars. --- RAh Right ascension (J2000) h RAm Right ascension (J2000) min RAs Right ascension (J2000) s DE- Declination sign --- DEd Declination (J2000) deg DEm Declination (J2000) arcmin DEs Declination (J2000) arcsec m152 UIT magnitude in the 152nm (B1) band UIT magnitude in the 152nm (B1) band. Magnitudes are defined as -2.5*log(flux)-21.1, where log is base 10, and flux is f sub lambda in units of ergs/cm2/s/A. mag C152-249 UIT color index 152nm (B1) - 249nm (A1) mag e_m152 Formal error in UIT 152nm (B1) magnitude mag e_m249 Formal error in UIT 249nm (A1) magnitude mag R Distance of UIT source from cluster center arcsec Qnote Note on quality of observation Note on quality of observation. *: UIT source is within 5 pixels (5.7arcsec) of more than one HB star of F92; if an F92 number is given, it is judged the most likely candidate according to color index and distance from the UIT source position. C: Obvious crowding in one or both UIT bands, as determined by inspection; stars without this note may still be affected by crowding if r<~40arcsec. Lowercase f or n: An aperture magnitude is substituted for a PSF magnitude with error greater than 0.2mag, for image FUV0141 or NUV0124, respectively. Entries 134-136 have aperture photometry only. --- IDF92 Star number from Ferraro et al., 1992 The complete reference F92 is the following: Ferraro, F. R., Clementini, G., Fusi Pecci, F., Sortino, R., and Buonanno, R., (1992MNRAS.256..391F) --- B-VF92 B-V color index from Ferraro et al., 1992 mag VmagF92 V magnitude from Ferraro et al., 1992 mag CDS 1997Jan30AAS CD-ROM series, Volume 7, 1996 Lee Brotzman [ADS] 13-Aug-1996 J_AJ_112_601.xml