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J/ApJ/841/92    Young massive star clusters in 2 LEGUS galaxies    (Ryon+, 2017)

Effective radii of young, massive star clusters in two LEGUS galaxies. Ryon J.E., Gallagher J.S., Smith L.J., Adamo A., Calzetti D., Bright S.N., Cignoni M., Cook D.O., Dale D.A., Elmegreen B.E., Fumagalli M., Gouliermis D.A., Grasha K., Grebel E.K., Kim H., Messa M., Thilker D., Ubeda L. <Astrophys. J., 841, 92 (2017)> =2017ApJ...841...92R
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Stars, ages ; Stars, masses Keywords: galaxies: general; galaxies: individual (NGC 628, NGC 1313); galaxies: star clusters: general Abstract: We present a study of the effective (half-light) radii and other structural properties of a systematically selected sample of young, massive star clusters (≥5x103M and ≤200Myr) in two nearby spiral galaxies, NGC 628 and NGC 1313. We use Hubble Space Telescope (HST) WFC3/UVIS and archival ACS/WFC data obtained by the Legacy Extragalactic UV Survey (LEGUS), an HST Treasury Program. We measure effective radii with GALFIT, a two- dimensional image-fitting package, and with a new technique to estimate effective radii from the concentration index of observed clusters. The distribution of effective radii from both techniques spans ∼0.5-10pc and peaks at 2-3pc for both galaxies. We find slight positive correlations between effective radius and cluster age in both galaxies, but no significant relationship between effective radius and galactocentric distance. Clusters in NGC 1313 display a mild increase in effective radius with cluster mass, but the trend disappears when the sample is divided into age bins. We show that the vast majority of the clusters in both galaxies are much older than their dynamical times, suggesting they are gravitationally bound objects. We find that about half of the clusters in NGC 628 are underfilling their Roche lobes, based on their Jacobi radii. Our results suggest that the young, massive clusters in NGC 628 and NGC 1313 are expanding, due to stellar mass loss or two-body relaxation, and are not significantly influenced by the tidal fields of their host galaxies. Description: The Legacy Extragalactic UV Survey (LEGUS; Calzetti+ 2015AJ....149...51C) is a Hubble Space Telescope (HST) Cycle 21 Treasury program, which obtained imaging of 50 nearby galaxies (within ∼13Mpc) in five filters with WFC3/UVIS and ACS/WFC. Separate catalogs are produced for each pointing on the two galaxies: NGC 628c (central pointing), NGC 628e (east pointing), NGC 1313e (east pointing), and NGC 1313w (west pointing). Objects: ---------------------------------------------------------------- RA (ICRS) DE Designation(s) Dist (Mpc) ---------------------------------------------------------------- 01 36 41.77 +15 47 00.5 NGC 628 = M74 D=9.9 03 18 16.05 -66 29 53.7 NGC 1313 = LEDA 12286 D=4.4 ---------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 107 320 Properties of young massive clusters (YMCs) in NGC 628 table4.dat 107 195 Properties of young massive clusters (YMCs) in NGC 1313
See also: J/A+AS/139/393 : Young Massive Star Clusters. II. (Larsen, 1999) J/A+A/416/537 : UBVI & HST photom. of young stellar clusters (Larsen, 2004) J/ApJS/161/304 : Star clusters in the MW & satellites (McLaughlin+, 2005) J/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006) J/ApJS/173/538 : XUV-Disk galaxies in the Local Universe (Thilker+, 2007) J/AJ/138/1667 : HST survey of young clusters in M31. III. (Barmby+, 2009) J/AJ/138/332 : LEDA CMD/tip of the red giant branch (Jacobs+, 2009) J/A+A/501/949 : Star cluster properties in 5 spiral galaxies (Mora+, 2009) J/MNRAS/401/1965 : Globular clusters in M104 (Harris+, 2010) J/AJ/140/75 : Antennae galaxies (NGC4038/4039) revisited (Whitmore+, 2010) J/A+A/529/A25 : Star cluster photom. in 5 nearby gal. (Silva-Villa+, 2011) J/MNRAS/452/525 : M83 young star cluster light profiles (Ryon+, 2015) J/ApJ/806/16 : CHemical Abundances of Spirals. I. NGC628 (Berg+, 2015) J/ApJ/812/147 : Slug analysis of star clusters in NGC628+7793 (Krumholz+, 2015) Byte-by-byte Description of file: table[34].dat
Bytes Format Units Label Explanations
1- 6 A6 --- ID Object identifier 8- 15 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000) 17- 25 F9.5 deg DEdeg Declination in decimal degrees (J2000) 27- 31 F5.3 mag CI [1.3/2.3] Concentration index in magnitudes 33- 36 F4.2 --- eta [1/9.3]? Power-law slope of EFF light profile (1) 38- 42 F5.2 --- e_eta [0.01/80]? Error in eta 44- 48 F5.2 [pc] logReffg [-0.6/15.5]? Log of half-light radius from GALFIT 50- 53 F4.2 [pc] E_logReffg ? Positive error in log Reff from GALFIT 55- 59 F5.2 [pc] e_logReffg ? Negative error in log Reff from GALFIT 61- 65 F5.2 [pc] logReffc [-0.6/1.3] Log of half-light radius from CI 67- 70 F4.2 [pc] E_logReffc Positive error in log Reff from CI 72- 75 F4.2 [pc] e_logReffc Negative error in log Reff from CI 77- 80 F4.2 [yr] logAge [6/8.3] Log of age 82- 85 F4.2 [yr] E_logAge Positive error on log age 87- 90 F4.2 [yr] e_logAge Negative error on log age 92- 95 F4.2 [Msun] logMass [3.7/5.7] Log of mass 97-100 F4.2 [Msun] E_logMass Positive error on log mass 102-105 F4.2 [Msun] e_logMass Negative error on log mass 107 I1 --- fvis [1/2] Visual inspection class, mode (2)
Note (1): The power-law index of the EFF light profile, η, describes the slope of the wings of a star cluster's intensity profile. The smallest possible value of η is artificially set to 1.0 by GALFIT because a light profile with η<1.0 must, by definition, contain an infinite amount of light. See section 4.3 for further explanations. Note (2): Class as follows: 1 = Compact and centrally concentrated with an FWHM more extended than that of a star. Homogeneous in color. 2 = Slightly elongated or asymmetric light profile shapes with an FWHM more extended than that of a star. Homogeneous in color. See section 2 for further explanations.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Jan-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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