J/AJ/123/1411 UBVIHalpha photometry of NGC 4314 star clusters (Benedict+, 2002) ================================================================================ NGC 4314. IV. Photometry of star clusters with the Hubble space telescope: history of star formation in the vicinity of a nuclear ring. Benedict G.F., Howell D.A., Jorgensen I., Kenney J.D.P., Smith B.J. =2002AJ....123.1411B ================================================================================ ADC_Keywords: Clusters, globular ; Clusters, open ; Photometry, UBVRI ; Photometry, H-alpha Keywords: galaxies: individual (NGC 4314) - galaxies: star clusters - galaxies: stellar content Abstract: Using Hubble Space Telescope (HST) WFPC2 images, we have obtained U, B, V, I, and H{alpha} photometry for 76 star clusters in the nuclear star-forming ring of the barred spiral galaxy NGC 4314. These clusters are likely associated with an inner inner Lindblad resonance (IILR). The blue colors and H{alpha} emission for most of these clusters imply very young ages of 115 Myr. Age estimates based on several reddening-free parameters indicate that the present epoch of star formation has lasted at least 30Myr. By estimating the masses of stars in the clusters and comparing with the H{alpha} luminosity, we conclude that a significant fraction of ongoing star formation in the nuclear ring of NGC 4314 occurs in clusters. The cluster masses identify these as young open clusters, not young globular clusters. Objects: ----------------------------------------- RA (2000) DE Designation(s) ----------------------------------------- 12 22 32.0 +29 53 44.1 NGC 4314 ----------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 59 76 Nuclear Ring Cluster Photometry table4.dat 31 76 Nuclear Ring Cluster Derived Quantities: A_V_, M_V_, and Mass table5.dat 26 76 H{alpha} Associated with Nuclear Ring Clusters -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- NRC Nuclear ring cluster identification (G1) 4- 8 F5.2 arcsec dRA Right Ascension relative to the galaxy center 10- 14 F5.2 arcsec dDE Declination relative to the galaxy center 16- 20 F5.2 mag Vmag The V band magnitude (1) 22- 25 F4.2 mag e_Vmag The uncertainty in Vmag 27- 31 F5.2 mag U-B The (U-B) color (1) 33- 36 F4.2 mag e_U-B The uncertainty in U-B 38- 42 F5.2 mag B-V The (B-V) color (1) 44- 47 F4.2 mag e_B-V The uncertainty in B-V 49- 53 F5.2 mag V-I The (V-I) color (1) 55- 58 F4.2 mag e_V-I The uncertainty in V-I -------------------------------------------------------------------------------- Note (1): Corrected for extinction within our Galaxy. -------------------------------------------------------------------------------- Table 3: Surface photometry of locations within blue arms -------------------------------------------------------------------------------- ID DRA DDE {mu}V0 {mu}(U-B)0 {mu}(B-V)0 {mu}(V-I)0 " " mag/arcsec^2^ mag/arcsec^2^ mag/arcsec^2^ mag/arcsec^2^ -------------------------------------------------------------------------------- A1 9.20 -2.87 21.97+/-0.04 -0.16+/-0.10 0.15+/-0.05 0.49+/-0.05 A2 8.88 -3.73 21.99+/-0.04 -0.14+/-0.10 0.17+/-0.05 0.49+/-0.05 A3 8.33 -4.51 21.73+/-0.03 -0.27+/-0.08 0.31+/-0.05 0.46+/-0.04 A4 7.74 -5.15 21.62+/-0.03 -0.10+/-0.08 0.15+/-0.04 0.56+/-0.04 A5 6.83 -5.78 21.74+/-0.03 -0.25+/-0.08 0.28+/-0.05 0.67+/-0.04 A6 6.01 -6.15 21.74+/-0.04 -0.35+/-0.08 0.39+/-0.05 0.73+/-0.04 A7 -9.24 2.78 22.12+/-0.04 -0.25+/-0.10 0.20+/-0.06 0.24+/-0.06 A8 -8.70 3.92 21.80+/-0.03 -0.14+/-0.09 0.13+/-0.05 0.48+/-0.04 A9 -8.02 4.78 21.91+/-0.04 -0.11+/-0.11 0.30+/-0.05 0.53+/-0.05 A10 -7.47 5.28 22.13+/-0.05 -0.23+/-0.12 0.38+/-0.06 0.56+/-0.05 A11 -6.60 6.10 21.93+/-0.04 -0.02+/-0.12 0.28+/-0.05 0.51+/-0.05 A12 -8.93 2.00 22.12+/-0.04 -0.23+/-0.08 -0.17+/-0.05 0.69+/-0.05 -------------------------------------------------------------------------------- Note: DRA and DDE are differential positions relative to galaxy center. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- NRC Nuclear ring cluster identification (G1) 4- 8 F5.2 mag AV The intrinsic V band extinction magnitude 10- 13 F4.2 mag e_AV The uncertainty in AV 15- 20 F6.2 mag VMAG The absolute V band magnitude (1) 22- 25 F4.2 mag e_VMAG The uncertainty in VMAG 27- 30 F4.2 10+4solMass Mass Derived cluster mass (see text) -------------------------------------------------------------------------------- Note (1): Assuming a distance of 13.1 Mpc. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- NRC Nuclear ring cluster identification (G1) 4- 8 F5.2 10-15mW/m2 FHa ? H{alpha} flux in 10^-15^erg/cm^2^/s (1) 10- 13 F4.2 10-15mW/m2 e_FHa ? Uncertainty in FHa (1) 15- 18 F4.1 [10-7W] LHa ? Log of the H{alpha} luminosity in erg/s (1) 20- 23 F4.1 mag Hamag ? H{alpha} extinction corrected magnitude (1) 25 A1 --- Age [OY] Age flag (2) -------------------------------------------------------------------------------- Note (1): Blank value indicates no detection. Note (2): Age flag: O = older than 15 Myr; Y = younger than 15 Myr. -------------------------------------------------------------------------------- Global notes: Note (G1): [BHJ2002] NRC NN in Simbad -------------------------------------------------------------------------------- History: From electronic version of the journal References: Benedict et al., Paper I 1992AJ....103..757B Benedict et al., Paper II 1993AJ....105.1369B Benedict et al., Paper III 1996AJ....111.1861B ================================================================================ (End) Greg Schwarz [AAS], Patricia Bauer [CDS] 06-Sep-2002