19 91Apjs. . .76. .185E the Astrophysical Journal Supplement

19 91ApJS. . .76. .185E T with verysmallcoreswhichthen gothroughaphaseofexpan- sion wasintriguing.Theprimary motivationforthepresent sented arealtrend,butthe possibility thatclustersareborn core radiiweretoocrude,to determinewhetherthisrepre- clusters hadlargerones.There weretoofewclusters,andthe clusters intheirsamplehadthesmallestcoreswhileolder p(r) whichvariedas/¿(r)ocr~,with7æ2.6.Theyoungest graphic plates.Theyfoundthattheouterpartsofclusters showed littleornotidaltruncationandhadsurfacebrightness Large MagellanicCloud(LMC)usingstarcountsfromphoto- surface brightnessprofilesfortenrichyoungclustersin the epoch whenglobularclustersformed. the processesthroughwhichacoreisinitiallyestablishedin haps theconditionsprevailinginhalosofgalaxiesat the cluster, andtheevolutionofthatcorepriortocollapse.Such of A-bodysystems,theformationglobularclusters,and per- studies couldcontributetoourunderstandingoftheevolution lapsed” cores(Djorgovski&King1986;Mateo1987;Meylan determine theproportionandpropertiesofclusterswith“col- ter evolution,hasprovokedconsiderableinterestoverthepast & Djorgovski1987).Relativelylittlehasbeendonetoexplore clusters intheMagellanicClouds,havebeenundertakento decade (seeElson,Hut,&Inagaki1987forareview).Several surveys ofglobularclustersintheGalaxy,andolder phenomenon expectedtooccurduringthelaterstagesofclus- The AstrophysicalJournalSupplementSeries,76:185-214,1991May © 1991.TheAmericanAstronomicalSociety.Allrightsreserved.PrintedinU.S.A. Elson, Fall,&Freeman(1987,hereafterEFF)determined Gravitational collapseinthecoresofglobularclusters,a THE STRUCTUREANDEVOLUTIONOFRICHSTARCLUSTERSINLARGEMAGELLANICCLOUD 79 guide forselectinginitialconditionstheoreticalmodelsofglobularclusterevolution. Subject headings:clusters:open—galaxies:MagellanicCloudsphotometrystars:stellarstatistics younger clustersarenotrelaxedthroughtwo-bodyencounters,theircurrentstructureshouldprovideagood tures ofmergingsubcondensations.ItseemslikelythatthehighellipticityobservedinmanyyoungLMC clusters evolve,andthismightaccountforthegeneralrounderappearanceofolderclusters.Finally,since clusters isdue,atleastinpart,tothepresenceofthesesubcondensations.Suchsubstructurewillbeerasedas then thesmallcoresofyoungestonesmayimplyformationfromrelatively“cool”initialconditions,while that dependsontheslopeofinitialmassfunction(IMF).Incontextthesemodels,datafavoranIMF sharp shouldersfavor“warmer”conditions.Analternativeinterpretationoftheisthattheyaresigna- 0.4-14M©), butwithsignificantcluster-to-clustervariations.Iftheclustershaveundergoneviolentrelaxation, by masslossfromevolvingstars.Recentmodelsofclusterevolutionpredictthatthecoresshouldexpandatarate the formofbumps,sharp“shoulders,”andcentraldips.Thesefeaturespersistinprofilesderivedfromimages for mostoftheclusterswithaslopeslightlyflatterthanSalpetervalue(forrangestellarmasses clusters. Thereisanupperlimittotheradiiofclustercores,andthisincreaseswithagefrom^1pc for theyoungestclusters,to^6pcoldestones.Thistrendprobablyreflectsexpansionofcoresdriven from whichthebrightstarshavebeensubtracted;theythereforeappeartoreflectrealsubstructurewithin models withaKing-likecore.Theprofilesofmanytheyoungerclustersshowdeparturesfromsuchin Magellanic Cloud(LMC),withages~10-10yr.Theprofilesoftheolderclustersarewellrepresentedby Bunting Institute,RadcliffeCollege;andHarvard-SmithsonianCenterforAstrophysics,60GardenStreet,Cambridge,MA02138 Surface brightnessprofilesandcolor-magnitudediagramsarepresentedfor18richstarclustersintheLarge © American Astronomical Society • Provided by theNASA Astrophysics Data System 1. INTRODUCTION Received 1990March19;acceptedSeptember14 Rebecca A.W.Elson ABSTRACT 185 -1 45 79 was adequatefordetermining clusterprofiles.Preliminaryre- tion (200sinFand4002?), andlimitingmagnitudeswere B ^Væ18.Seeingranged from ~2"-5"which,whilepoor, was 0?56pixel.Integration timeswereshorttoavoidsatura- shown inFiguresl<2-ls(Pis. 26-35).AtF/8theimagescale tory, andtheMSSSOcoatedGECchipNo.2;Limages are ters are^10-10M;EFF).TheclusterslistedinTable 1. these globular-likeclusters.(Theestimatedmassesoftheclus- uary 12-14,usingthe1mtelescopeatSidingSpringObserva- Images intheBandVpassbandswereobtainedon1988 Jan- ages ~10-10yr,wereobtainedtoprovideasequence of “snapshots,” toinvestigatetheevolutionofinnerparts of cussed in§3,andsummarized4. The observationsaredescribedin§2,andtheresultsdis- project, whichcomplementsthatofEFF,wastoinvestigate surface brightnessprofilesforthe18clustersintheirsample. Elson etal.arebased,includingcolor-magnitudediagramsand core expansionduetomasslossfromstellarevolution. evolution byChemoff&Weinberg(1990)predictjustsuch age didindeedpersist.Furthermore,recentmodelsofcluster whether arelationbetweencoreradiusandagewasevidentin core radii.AsynopsisoftheresultswasgivenbyElson,Free- larger sampleofclusterswithmoreaccuratemeasurements man, &Lauer(1989):thetrendofincreasingcoreradiuswith o CCD imagesof18therichestclustersinLMCwith This paperpresentsthefullsetofdataonwhichresults 2. OBSERVATIONS 19 91ApJS. . .76. .185E PLATE 26 © American Astronomical Society •Provided bythe NASAAstrophysics Data System 19 91ApJS. . .76. .185E Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System Ûh o Fig. \c PLATE 27 Elson (see76,185) 19 91ApJS. . .76. .185E PLATE 28 © American Astronomical Society •Provided bythe NASAAstrophysics Data System

FlG- le Fig. 1/ 19 91ApJS. . .76. .185E Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System PLATE 29 19 91ApJS. . .76. .185E Elson (see76,185) PLATE 30 © American Astronomical Society •Provided bythe NASAAstrophysics Data System

Fra. \h nG. 1, 19 91ApJS. . .76. .185E Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System

Fig. Ik 19 91ApJS. . .76. .185E PLATE 32 © American Astronomical Society •Provided bythe NASAAstrophysics Data System £ o S 19 91ApJS. . .76. .185E Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System

Fig. \n Fig. \o PLATE 33 19 91ApJS. Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System

FKj. \p pIG 19 91ApJS. . .76. .185E Elson (see76,185) © American Astronomical Society •Provided bythe NASAAstrophysics Data System

Fig. Is PLATE 35 19 91ApJS. . .76. .185E were convertedtoapparentmagnitudesusingobservations of four standardstarslistedinTable2(Graham1982).Photo- results onluminosityfunctions.Theinstrumentalmagnitudes and theimageswerenotdeepenoughtoprovideinteresting tained byfittingpoint-spreadfunctions.Incrowdedregions magnitudes sinceitwasnotnecessaryfordeterminingages, multaneously. Noattemptwasmadetobecompleteatfaint magnitudes ofoverlappingstellarimagesweredeterminedsi- cluster framewitha“detector”constructedfromthepoint- spread functionofastarinthatframe(seeLauer&Kormendy algorithm whichenhancesstellarimagesbycorrelatingeach ductions, includingbias-subtractionandflat-fieldingwere ing magnitude,wereidentifiedautomaticallyusingaVISTA low, wasdonewithVISTA(Lauer,Stover,&Turndrup1983). done withFIGARO;subsequentimageanalysis,describedbe- the subscriptzerodesignates valuescorrectedforextinction. where lowercaselettersindicate instrumentalmagnitudes,and The scatterofthestandard starmeasurementsaboutthe least-squares fitsgivenby metric transformationsareshowninFigure2;thelines are 1986 ).Instrumentalmagnitudesforthesestarswherethenob- cols. (5)and(6),correctedforseeingasdescribedinthetext.Valuesarearcseconds.Errorssame(6). cleaned images.Cols.(5)and(6):Coreradiusinarcsecondsfromcleaned,background-subtractedprofiles.Nocorrectionsforseeinghave beenapplied. 186 Uncertainties aretheformalerrorsfromfittingeq.(2).Cols.(7)and(8):FWHMofGaussianseeingdiskinarcseconds.(9)(10): Core radiusfrom values, whicharefromElson&Fall1988.Typicaluncertaintiesblog(r/yr)«±0.2.Col.(4):Magnitudebrighterthanstarswere removedinthe NGC 2214 NGC 2172 NGC 2164 NGC 2159 NGC 2157 NGC 2156 NGC 2004 NGC 1872 NGC 1866 NGC 1850 NGC 1831 NGC 2100 NGC 2002 NGC 1868 NGC 1855 NGC 1818 NGC 1755 NGC 1711 {V-v) =(-0.022±0.012)(£-F)+(22.2030.006), Q All starsineachBandVframe,downtoroughlythelimit- NGC Number {b -v)=(0.864±0.013)(BF)+(0.4770.007), Notes.—Col. (2):ReddeningfromPerssonetal.(1983).Col.(3):Age[log(r/yr)]CMDsinFigs.3¿z-3<9,andisochronesFig.4,except forbracketed 0 (1) © American Astronomical Society • Provided by theNASA Astrophysics Data System 2.1. Color-MagnitudeDiagrams E(B- V) 0.10 0.10 0.10 0.10 0.10 0.06 0.13 0.10 0.10 0.24 0.12 0.07 0.12 0.15 0.10 0.10 0.12 0.16 (2) (8.1) (8.7) (8.5) Age 7.6 7.6 7.6 7.6 7.3 7.7 7.6 7.2 7.2 7.6 7.5 7.5 7.3 7.4 7.5 (3) 17.5 18.0 17.0 18.0 17.5 18.0 16.0 16.0 16.5 17.5 19.5 17.0 16.5 16.5 16.5 16.5 18.5 17.0 (4) Cluster Parameters 10.5 ±0.7 10.0 ±1.4 13.6 ±0.4 10.7 ±0.9 10.2 ±0.7 15.7 ±0.9 9.6 ±1.3 7.1 ±2.4 7.4 ±0.4 8.1 ±1.0 6.0 ±0.3 9.4 ±1.4 6.7 ±0.5 8.2 ±0.7 5.6 ±0.7 7.1 ±0.6 3.5 ±0.4 (1¿) (la) >5.6 rJ,V) (5) TABLE 1 ELSON an giant branchesinFigures3a-3o,andincreasesomewhatthe will contributesomeofthescatterinmain-sequencesand are generally1-2magdeeperthanthepublishedones.Figure 4 Hodge 1975;Floweretal.1980;1984),butourCMDs etry existsfortheother10clusters(Robertson1974;Flower & NGC 2002,havenopublishedCMDs.Photographicphotom- clusters, NGC1711,1755,1855,1872,and uncertainty intheagesderivedfromCMDs.)Fiveof cate thatatradii<100"fromthecenters,expectedfraction improve ontheCMDsalreadyavailableinliterature of fieldstarsisonly10%-30%.(Contaminationbythese field interlopers.StarcountsbyEFFin10oftheclustersindi- shown inFigures3a-3o.Noefforthasbeenmadetoeliminate (Hodge 1984;Robertson1974;Floweretal.1980). oldest inthesample,andourimageswerenotdeepenoughto stars within100"ofthecentereachcluster,exceptforNGC (b-v). MagnitudesandcolorsarelistedinTables3A-30for adopted transformationsis±0.007inF-pd±0.012 1831, NGC1866,and1868.Thesethreeclustersarethe 0 0 Color-magnitude diagrams(CMDs)fortheclustersare 10.8 ±0.7 10.4 ±1.4 14.7 ±0.4 11.3 ±0.9 10.4 ±0.5 15.1 ±0.5 7.9 ±0.5 9.2 ±0.8 6.1 ±0.7 8.6 ±1.1 6.0 ±1.5 6.4 ±0.3 9.5 ±1.3 5.9 ±0.5 8.4 ±0.6 7.2 ±0.5 7.4 ±0.5 >6.1 rJStar VB-V FWHM(F) Photometric Standards 4.6 2.2 2.0 4.4 5.3 5.3 2.0 2.0 4.1 3.9 3.7 2.2 3.9 3.1 3.5 3.3 3.2 (7) 1.8 TABLE 2 FWHM(B) 2.3 2.9 2.1 4.5 4.2 5.7 5.4 2.4 2.3 5.7 3.6 5.0 5.1 3.8 3.9 3.1 3.7 3.5 (8) ^3.5 >4.7 rÁV) 11.7 14.2 (9) 4.3 7.2 6.4 6.7 8.5 8.0 5.7 9.0 8.6 8.8 7.9 5.1 5.7 5.8 Vol. 76 >5.1 <6.0 (10) 12.5 13.4 4.9 4.7 7.6 7.9 8.6 8.3 5.9 6.7 9.3 6.2 8.8 7.9 5.3 5.9 19 91ApJS. . .76. .185E tudes toapparentmagnitudes.DataareforE-regionstandardsinTable2, observed on1988January12(circles),13(triangles),andJan- uary 14(squares).Linesareleast-squaresfitsgivenbyeqs.(la)and(lb). tracks wereconvertedfromthetheoreticaltoobservational those fromRobertson(1974).Theoverallagreementisgood. branch, andwehavetakenthisintoaccountinfitting the time onthesecondratherthanfirstcrossingofgiant plane usingatmospheresfromVandenberg(1983)andKur- evolution tracksofBecker(1981)andBrunish&Truran Fall (1988).Fortherestofclusters,ageswereestimated NGC 1868,agesweretakenfromthecompilationbyElson& giant branchsuggestsanage oflog(r/yr)=7.5,whilethe isochrones. WeadoptedadistancemodulusfortheLMC of Madore (1990)havepointedout,starsspendmostoftheir isochrones areshowninFigure5.AsMateo,Olszewski, & (1982) forstarswith3

X B-V N V B-V N V B-V 184 206 18.24 0.10 61 319 191 17.45 0.50 121 393 133 17.83 -0.11 186 183 18.48 0.16 62 319 166 16.75 0.12 122 393 169 14.31 0.07 193 215 18.13 0.17 63 321 218 16.52 0.18 123 394 225 17.61 0.01 193 131 16.73 1.57 64 323 278 17.16 0.00 124 395 153 16.31 0.00 200 140 16.79 0.03 65 324 145 16.82 0.16 125 397 247 16.91 0.08 208 205 17.76 0.03 66 327 169 16.43 0.09 126 398 92 16.39 0.11 212 250 18.37 0.16 67 330 41 17.42 -0.05 127 400 206 16.51 -0.04 222 94 17.93 0.23 68 331 120 17.00 0.08 128 402 27 18.69 -0.05 224 270 18.33 1.37 69 332 18 18.13 0.08 129 401 54 18.58 ,32 227 228 18.60 0.03 70 332 296 17.67 0.06 130 403 78 17.01 ,08 228 143 17.17 0.08 71 332 206 16.31 -0.02 131 404 174 17.65 ,40 228 250 17.84 0.08 72 335 140 16.33 0.00 132 406 136 18.05 ,10 236 240 17.99 0.82 73 335 184 16.57 0.08 133 408 210 14.92 ,62 239 137 18.16 0.43 74 339 257 18.66 0.12 134 409 317 17.54 ,93 244 237 16.81 0.09 75 339 132 16.74 0.57 135 411 241 18.44 1.04 245 48 17.47 2.12 76 339 283 17.67 2.10 136 411 76 16.95 1.16 245 146 18.26 -0.05 77 340 197 16.68 -0.08 137 411 130 18.42 0.41 250 91 17.48 1.42 78 340 161 13.49 0.16 138 412 189 17.47 0.04 252 232 16.97 1.21 79 340 214 14.54 0.16 139 416 281 17.84 0.04 255 73 18.17 0.73 80 341 51 18.30 0.04 140 417 225 17.22 0.26 257 280 17.64 1.20 81 343 287 18.81 -0.62 141 420 203 17.73 -0.01 260 196 15.03 1.51 82 345 274 18.63 0.16 142 421 90 16. 95 2.32 260 172 18.19 -0.08 83 346 19 17.37 -0.01 143 423 168 14.92 75 262 74 17.21 0.10 84 346 37 16.00 -0.03 144 423 129 16.31 10 263 153 18.29 0.09 85 347 122 16.66 19 145 427 151 18.33 -0.02 264 251 16.71 08 86 349 190 16.87 04 146 426 227 17.00 0.02 265 215 17.33 35 87 351 155 14.08 32 147 429 80 18.12 04 269 57 18.11 62 88 351 167 14.19 21 148 431 289 17.93 05 271 200 18.21 12 89 351 131 16.37 29 149 433 217 18.53 -0.10 270 224 17.23 0.10 90 351 234 16.62 0.05 150 435 266 17.82 -0.05 271 309 18.62 -0.13 91 352 53 18.04 0.03 151 441 85 17.07 0.59 271 286 18.34 0.25 92 355 111 15.09 0.19 152 444 231 17.30 -0.03 272 298 18.44 1.50 93 356 224 16.60 0.08 153 444 30 17.41 02 276 267 15.11 1.84 94 358 71 16.58 0.05 154 444 201 16.89 00 277 276 16.36 29 95 360 161 15.42 0.38 155 447 216 18.19 06 277 66 16.84 03 96 360 141 13.57 1.58 156 447 255 18.34 15 279 229 18.34 13 97 362 47 17.01 0.22 157 448 75 18.35 08 281 294 18.40 50 98 362 189 18.07 -0.68 158 450 141 13.96 0.72 282 158 16.81 0.17 99 362 302 18.45 0.19 159 452 90 18.33 -0.01 282 34 16.22 0.05 100 363 152 14.34 0.14 160 454 123 18.42 0.32 285 283 15.10 1.58 101 366 92 17.77 0.26 161 454 224 17.78 0.07 286 139 16.11 -0.05 102 367 330 18.30 0.10 162 454 67 17.81 0.20 286 167 17.01 0.31 103 371 168 14.91 2.07 163 455 181 17.44 0.06 292 151 17.07 -0.38 104 372 219 18.45 0.16 164 461 55 14.59 0.00 293 176 15.15 1.51 105 372 46 16.75 0.07 165 462 78 17.49 -0.32 294 205 17.62 0.04 106 373 126 17.40 0.10 166 463 269 17.01 0.18 294 68 13.93 0.53 107 374 26 17.95 0.03 167 464 87 17.82 -0.12 295 48 17.92 0.15 108 374 156 14.38 0.01 168 466 154 17.92 0.09 299 184 16.86 0.25 109 375 178 15.97 .05 169 468 137 18. 60 0.05 302 296 17.15 0.09 110 375 236 18.09 .19 170 470 65 13.91 0.22 304 161 13.60 0.25 111 380 129 16.73 .02 171 471 180 15.34 0.81 304 213 17.83 1.55 112 381 147 15.36 .29 172 485 174 17.05 0.09 308 77 16.46 -0.03 113 381 188 14.95 1.34 173 485 72 14.65 0.11 309 224 15.53 0.05 114 380 249 18.28 1.12 174 488 56 16.24 0.04 313 265 18.17 0.16 115 382 274 18.84 -0.36 175 488 152 18.00 0.11 314 138 13.97 0.27 116 384 164 14.98 1.69 176 496 180 18.09 0.12 315 90 15.98 0.03 117 386 239 16.74 -0.13 177 500 86 17.30 -0.06 317 251 16.98 0.07 118 387 60 18.06 0.03 178 517 175 17.11 0.16 317 66 17.17 0.00 119 389 94 17.59 0.38 179 517 145 16.70 1.65 318 183 16.39 0.84 120 391 121 16.41 -0.22 180 523 165 15.78 0.05

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X V B-v N V B-V N V B-V 174 171 16.28 0.83 61 292 35 17.86 0.04 121 365 201 14.53 0.06 177 140 18.90 13 62 294 216 18.74 16 122 367 128 15.96 -0.04 188 193 18.18 09 63 296 207 19.16 36 123 368 179 14.11 0.10 189 203 19.36 14 64 297 119 18.53 17 124 369 248 18.43 0.05 189 230 16.41 11 65 298 183 17.14 06 125 370 166 14.45 0.76 191 151 19.32 77 66 299 142 16.22 10 126 373 47 19.26 0.12 192 212 18.87 16 67 301 84 18.21 10 127 373 86 18.12 0.01 191 134 19.07 0.15 68 305 210 18.77 0.10 128 374 219 14.18 0.17 201 82 19.32 0.97 69 305 329 17.68 0.00 129 375 2 17.51 0.92 203 253 18.87 1.07 70 305 280 13.60 1.02 130 376 109 17.59 0.02 203 176 18.02 0.06 71 306 167 15.26 0.79 131 376 274 19.07 -0.04 204 222 19.85 -0.03 72 309 66 18.85 0.69 132 377 123 18.00 -0.07 205 233 19.11 0.44 73 313 175 14.25 0.15 133 377 72 17.73 -0.06 205 145 19.60 1.17 74 313 195 17.58 -0.15 134 377 202 16.46 0.68 210 126 16.91 -0.08 75 314 110 16.78 -0.07 135 380 326 17.99 0.18 215 51 18.19 0.12 76 314 224 19.53 -0.33 136 382 259 19.27 0.61 219 67 19.70 1.02 77 315 130 17.80 -0.04 137 382 194 17.18 0.31 219 188 18.03 -0.12 78 317 322 19.09 0.45 138 384 20 16.96 0.02 220 78 19.15 0.06 79 316 334 18.75 0.18 139 384 153 14.62 1.22 228 171 18.55 0.25 80 317 246 17.40 1.30 140 383 186 16.78 0.52 228 85 18.31 0.05 81 317 293 17.35 -0.02 141 387 339 18.87 19 230 242 18.78 62 82 318 15 18.70 0.04 142 388 166 14.87 25 233 211 18.54 05 83 320 54 18.44 0.00 143 391 70 19.07 22 236 220 19.14 34 84 320 42 16.77 -0.01 144 391 269 18.14 03 240 193 18.17 91 85 322 70 18.56 0.30 145 392 178 16.52 01 240 155 16.77 30 86 325 121 17.19 -0.10 146 393 111 19.27 03 241 238 19.04 18 87 327 4 17.24 1.35 147 394 221 18.36 -0.37 244 52 18.39 19 88 326 85 18.93 0.36 148 393 231 18.56 0.67 245 115 18.97 -0.05 89 329 226 16.58 1.13 149 396 317 18.48 0.33 245 70 16.27 -0.03 90 330 303 19.26 0.02 150 396 304 18.16 0.25 246 27 16.92 0.47 91 331 323 19.25 -0.11 151 397 2 19.42 1.16 246 290 13.22 27 92 333 274 16.69 1.23 152 399 34 16.47 0.85 249 264 18.65 00 93 332 185 17.80 42 153 396 162 16.21 0.14 251 128 18.25 05 94 332 213 18.51 25 154 400 240 18.94 18 257 39 17.55 47 95 334 337 18.87 12 155 402 138 18.64 10 258 245 18.50 1.52 96 334 166 14.53 32 156 407 70 19.40 35 261 188 19.20 16 97 335 150 14.92 41 157 408 184 16.55 08 261 256 18.20 06 98 338 32 17.29 12 158 409 260 15.79 03 262 52 18.69 35 99 340 242 15.38 40 159 409 273 18.91 40 264 279 17.66 1.26 100 340 198 17.47 19 160 411 281 18.72 69 264 303 18.94 1.35 101 344 163 14.44 51 161 410 5 18.47 0.25 265 86 18.19 09 102 343 128 17.06 05 162 414 303 18.98 0.08 265 172 17.49 09 103 344 11 18.56 31 163 415 157 15.78 -0.05 267 144 19.17 14 104 345 324 17.82 89 164 417 72 18.45 0.84 267 207 18.35 09 105 345 296 17.83 01 165 418 124 18.73 0.72 268 67 19.09 00 106 345 138 16.17 02 166 418 208 17.51 0.21 268 20 16.62 20 107 348 252 17.98 06 167 419 106 19.08 0.05 269 131 18.54 0.16 108 348 277 17.97 11 168 419 19 18.67 -0.16 275 169 17.35 -0.13 109 348 49 19.25 13 169 423 172 18.58 0.12 276 108 18.98 0.81 110 350 83 17.35 02 170 427 225 15.44 1.38 275 262 18.73 0.05 111 350 156 14.21 81 171 428 293 17.54 0.00 277 119 17.96 16 112 352 175 14.62 06 172 428 137 18.10 0.94 277 308 18.58 16 113 354 161 14.92 24 173 429 244 16.50 1.44 278 73 19.27 26 114 354 218 17.02 -0.01 174 429 192 15.92 -0.08 279 241 19.57 19 115 357 7 5 17.79 0.00 175 430 52 19.56 0.89 279 44 15.07 13 116 356 308 18.13 0.05 176 431 114 18.76 0.04 280 289 19.03 09 117 360 14] 14.56 1.14 177 431 208 18.46 0.03 281 187 17.01 1.36 118 360 61 19.16 -0.02 178 434 87 18.35 -0.16 283 263 18.15 0.29 119 361 1 9 18.63 0.60 179 434 310 19.08 0.52 291 158 17.84 -0.15 120 361 159 14.56 0.14 180 435 10 19.37 0.54

189

© American Astronomical Society • Provided by the NASA Astrophysics Data System 19 91ApJS. . .76. .185E 40 27386 39 273126 38 269234 37 267172 36 267294 35 266187 34 264208 32 26061 31 259209 29 25794 33 26234 30 258137 28 257114 27 25144 26 251121 25 250263 23 24972 21 243272 24 250191 22 247169 20 243209 191 45325 18 240256 193 458225 192 45687 190 453200 189 450172 19 242285 17 241149 16 227172 188 450184 187 44883 185 44671 183 444219 15 225193 14 226243 13 22448 12 223128 186 448302 184 446137 182 442252 181 436265 11 214151 10 214177 N XYVB-V 5 205143 3 187159 2 18478 8 209205 7 208258 4 195237 9 212284 1 184235 6 206158 N XY © American Astronomical Society • Provided by theNASA Astrophysics Data System 15.60 -0.27 14.55 1.37 13.49 1.72 15.27 -0.16 16.37 -0.08 17.22 -0.12 16.40 -0.04 16.06 -0.08 18.26 0.28 16.04 0.00 16.03 0.03 17.05 -0.14 16.75 -0.09 15.91 0.11 18.23 0.14 18.98 0.51 17.12 0.00 16.74 -0.16 17.08 0.05 16.77 -0.25 15.75 -0.04 17.21 -0.10 18.62 1.38 17.80 0.19 18.00 0.53 18.17 0.13 18.41 0.65 17.55 0.00 18.28 -0.08 17.42 -0.06 18.25 0.69 18.36 0.07 17.82 0.00 17.31 0.02 18.30 0.25 18.54 2.13 17.24 -0.04 17.31 -0.05 17.28 0.06 17.35 0.01 18.78 0.03206 18.32 0.84205 19.29 1.04204 18.87 0.29203 18.69 0.88202 18.50 -0.04201 19.37 0.48200 18.23 -0.06199 18.58 -0.13198 17.17 -0.12197 19.08 -0.08196 19.44 0.34194 18.26 -0.11195 V B-VN 80 34329 79 342225 78 338240 77 334253 76 33383 75 33259 74 332205 73 329270 71 326118 72 32842 70 327134 69 324301 68 323234 67 321181 66 319217 58 30754 65 318121 63 315165 59 309278 57 304146 56 302176 55 30186 54 299245 64 31713 62 311141 60 309246 53 298216 61 310266 52 296134 51 289146 50 287187 49 28658 47 284126 48 285177 46 283227 45 281206 44 279259 43 27841 42 276160 41 27553 C NGC1818(Center:343,162) B. NGC1755—Continued 479 7119.53 481 22118.65 476 18718.97 477 27417.03 475 14816.47 471 3920.06 473 21018.08 468 25418.66 466 5717.73 462 30018.58 462 7219.71 459 21619.35 457 18017.88 X YV 190 14.79 1.73 16.63 -0.13 19.19 -0.61 12.63 0.11 18.53 1.32 17.15 -0.04 16.54 0.00 18.46 0.00 17.30 0.47 13.68 1.57 15.48 -0.10 18.09 -0.01 17.65 0.47 14.36 1.71 14.92 -0.13 14.65 0.32 14.58 0.08 17.48 -0.06 15.95 -0.10 15.90 0.05 16.46 -0.02 18.86 -0.15 18.53 -0.02 16.96 -0.34 16.36 0.15 16.48 -0.06 17.55 0.18 16.23 -0.13 16.44 -0.11 17.52 0.09 16.50 -0.09 16.93 -0.11 17.79 -0.17 16.16 -0.06 16.94 0.01 18.42 0.05 17.34 0.93 16.54 -0.11 17.63 0.53 18.03 0.12 -0.05 217517 -0.05 215504 -0.14 214504 -0.28 213497 -0.01 210489 0.09 219520 0.03 218519 0.58 216508 0.16 212495 0.63 211491 0.06 209486 0.08 208485 0.82 207482 B-V NX 120 40682 119 406196 118 403230 117 40317 116 399270 115 397257 114 396148 113 392205 112 391198 111 389125 110 38865 109 385277 108 385232 107 384153 106 383243 105 381215 103 379117 104 37952 102 379184 101 378177 100 377163 99 374200 98 373182 97 37181 96 371218 95 37188 89 355226 94 370145 93 368129 91 358335 88 355178 87 349217 85 344260 84 346317 82 344145 92 361281 90 356240 86 347190 83 345166 81 34357 131 19.220.01 181 19.400.83 117 17.730.56 133 18.290.05 226 17.011.64 207 18.341.15 172 14.74-0.10 147 19.320.07 248 17.771.37 237 19.79-0.41 114 18.400.09 125 16.72-0.09 59 17.821.34 Y VB-V 16.46 0.09 15.81 -0.07 12.99 0.05 16.35 -0.08 18.05 -0.08 17.56 -0.07 18.27 0.48 17.73 -0.22 18.81 -0.58 16.44 -0.05 16.81 -0.16 16.78 1.73 16.88 -0.01 15.39 -0.22 17.89 -0.25 17.26 0.10 17.96 0.08 17.59 -0.63 17.67 0.96 16.47 -0.12 16.14 0.06 16.84 0.13 16.56 -0.25 18.01 0.14 14.34 0.05 16.78 -0.09 16.04 0.59 14.43 1.41 13.67 -0.05 18.82 1.46 16.07 -0.04 17.73 -0.07 15.77 0.05 13.68 1.02 15.46 0.05 18.65 -0.35 Í8.36 0.16 12.94 0.50 13.62 0.10 18.41 -0.12 19 91ApJS. . .76. .185E 42 24263 130 43267 129 42780 128 423171 122 416185 43 246244 38 237138 37 236169 36 235300 131 434128 127 422114 126 421198 125 420278 124 420140 123 416253 121 415235 41 239190 40 238206 39 237128 35 234150 34 234245 33 233235 32 231223 31 230141 30 229207 29 23082 28 226266 27 224239 26 225164 25 22344 24 222253 23 219222 22 219125 21 219139 20 216208 19 21566 18 214261 14 20868 13 204135 17 212166 16 211114 15 211189 12 204146 11 203157 10 203202 N XYVB-V 2 178126 5 183155 3 180222 1 175188 8 20077 7 198231 4 183211 9 201211 6 194185 N XY © American Astronomical Society • Provided by theNASA Astrophysics Data System 18.29 0.00 18.43 0.21 16.94 0.61 16.94 -0.16 18.43 -0.02 17.55 0.08 18.35 0.25 14.93 0.66 17.40 -0.04 18.39 -0.05 17.18 -0.09 18.00 0.38 16.84 2.20 17.90 0.62 17.42 1.24 17.45 0.46 17.35 -0.08 18.26 -0.05 17.66 1.28 17.66 -0.03 17.29 0.06 17.40 0.26 17.62 0.46 17.84 0.13 17.56 0.02 18.32 1.01 18.19 -0.12 18.86 0.14 17.52 -0.02 17.15 0.55 17.43 0.48 17.72 -0.10 15.84 -0.07 18.24 0.20 16.82 0.03 16.62 -0.01 17.85 -0.06 18.30 -0.33 18.05 -0.36 14.49 -0.04 17.90 -0.17 15.06 0.57 16.65 1.03 15.86 -0.03142 18.11 0.70141 18.66 -0.19140 15.83 -0.09139 16.04 -0.11137 16.31 -0.07136 17.25 -0.14135 17.93 -0.06134 16.43 -0.02133 16.56 -0.14138 17.67 -0.19132 V B-VN 86 294142 85 291233 84 290178 82 289212 81 289316 83 289273 80 28891 79 288237 78 287123 77 28742 76 283162 75 28079 74 279214 73 27728 72 277189 71 276242 70 275200 59 263247 58 26134 57 260279 56 260138 51 256259 50 257228 55 26171 54 257128 53 257168 52 257302 69 27562 68 273132 63 26784 45 247203 67 273228 66 27051 65 268160 64 268142 62 264267 60 263197 49 250158 48 24989 47 248231 46 247274 44 246212 61 26358 D. NGC1850(Center:348,164) C. NGC1818—Continued 460 12817.94 459 22918.23 471 20018.00 469 17118.69 455 24718.26 450 5418.39 445 18217.00 443 14915.77 442 29717.61 442 22616.10 435 20917.45 X YV 191 17.23 -0.25 15.36 0.47 15.61 1.77 17.96 -0.20 15.99 0.08 14.96 0.37 17.32 -0.04 17.47 0.88 17.88 0.89 13.84 1.72 16.49 1.24 15.42 1.11 18.81 -0.02 16.14 0.07 17.24 -0.17 14.94 1.27 17.25 -0.15 17.84 0.43 16.49 -0.09 16.65 -0.04 17.71 0.19 17.48 0.05 17.01 0.17 18.08 -0.06 17.73 -0.24 17.87 0.17 17.83 0.33 13.89 -0.10 15.59 1.39 17.43 -0.10 13.85 -0.15 18.63 -0.16 16.49 0.65 15.07 0.43 17.92 -0.26 17.31 0.96 15.07 0.30 17.65 0.19 18.03 0.37 18.39 0.15 15.06 0.34 16.76 -0.02 15.83 2.35 -0.38 149490 -0.08 147484 -0.01 143472 2.20 144474 1.35 1.03 151515 0.63 150498 1.20 145476 0.66 152515 0.80 148484 0.69 146480 B-V NX 129 335258 128 33456 123 325124 127 332149 126 331180 125 330196 124 327247 122 325141 120 325177 119 325287 118 32682 121 325226 117 323318 116 321260 114 319143 113 319125 112 318271 111 317291 110 316163 109 316239 108 316306 115 319218 107 315207 106 31364 105 313261 104 311187 103 310202 102 30947 101 307126 100 306154 88 29317 89 29479 87 29354 99 30772 97 306222 96 306295 94 299264 92 297305 91 296129 90 295250 98 306113 95 30427 93 298204 200 18.240.99 211 17.93-0.01 150 18.201.26 219 17.821.63 207 16.56-0.04 228 16.67-0.02 260 17.10-0.03 117 18.28-0.09 183 17.611.10 251 17.03-0.06 Y VB-V 17.68 0.30 18.29 -0.10 14.73 -0.06 15.89 1.01 14.40 0.37 16.42 0.30 16.80 -0.15 14.81 0.24 15.15 -0.04 17.18 -0.09 17.71 0.15 16.82 -0.26 14.93 0.13 17.27 0.09 15.97 -0.03 15.51 0.36 17.63 -0.09 16.93 0.66 16.60 0.84 15.40 0.25 16.00 -0.20 17.73 0.62 16.31 0.11 17.19 0.11 16.06 0.11 17.74 -0.44 14.32 0.13 15.75 0.25 14.98 0.16 17.86 -0.23 18.40 -0.16 15.52 1.27 17.70 0.91 16.13 0.96 14.88 2.31 16.86 0.00 17.65 0.59 17.65 -0.02 16.91 -0.09 13.91 0.19 17.30 0.06 16.47 -0.46 16.72 -0.04 19 91ApJS. . .76. .185E 183 383320 182 383197 181 38332 180 38383 179 381167 178 37821 177 377187 176 377212 175 375277 174 373219 173 37266 172 37194 171 371257 170 371176 169 370146 166 368134 168 367246 167 36783 165 364119 164 364154 163 364263 162 362184 161 36279 160 362229 159 361198 158 361289 157 359244 156 359319 155 35989 154 357175 153 35834 152 35646 150 354209 149 353238 151 355302 148 35220 147 352168 146 352144 145 352160 144 351181 143 349153 142 34933 141 348191 140 347267 139. 345287 138 343121 137 '345254 135 344221 136 344209 134 341337 133 341121 132 33924 131 338167 130 338241 N XY © American Astronomical Society • Provided by theNASA Astrophysics Data System 18.16 1.34237 17.60 0.15236 18.01 0.30235 15.61 -0.02234 17.55 0.14232 14.76 0.24233 16.96 0.28231 13.89 -0.15230 14.07 -0.16229 15.25 0.90228 14.88 0.23227 17.57 -0.43226 17.57 -0.23225 13.73 0.50224 15.94 1.52223 18.43 0.16222 16.95 0.13221 15.76 1.21220 15.11 0.63219 17.19 -0.40217 16.44 0.63218 15.21 0.34216 17.61 -0.16215 17.22 0.03214 15.98 0.95213 17.86 -0.29212 17.80 0.17211 18.22 -0.07210 15.89 0.95209 16.45 -0.22208 18.55 0.18207 16.53 0.06206 15.13 -0.01202 15.31 -0.17205 15.36 0.30204 16.55 -0.48203 14.93 0.21201 14.84 1.15200 15.78 0.53198 14.72 0.31197 16.67 0.07196 14.26 0.45199 15.87 0.90195 16.43 0.01194 16.36 1.35193 16.57 -0.54192 17.06 -0.02191 15.27 0.62190 12.89 -0.22189 15.60 1.23187 17.77 1.03188 15.10 1.29186 14.37 0.10185 14.79 -0.06184 V B-VN D. NGC1850—Continued 432 15615.26 433 5417.58 430 23617.47 428 2818.30 427 17316.98 427 31518.19 427 13618.35 427 19416.71 426 25014.78 425 26317.72 422 28217.26 421 7017.24 421 29918.26 419 7915.90 420 17615.93 418 32716.50 417 12216.66 416 20717.42 417 8516.47 415 15818.61 415 21517.45 414 22415.24 411 31416.54 411 5415.30 410 4214.78 409 18716.03 409 18016.66 406 6917.42 404 22017.16 405 15715.68 405 27115.31 404 7117.24 404 1418.20 404 9215.53 401 24816.20 399 32915.94 397 7917.01 396 6315.99 403 30215.43 400 20816.65 395 16015.34 395 13317.43 392 1515.42 391 18417.14 390 31716.92 391 26017.72 390 4018.40 389 14215.81 389 27116.64 387 17416.05 386 33217.05 385 30114.45 385 24616.06 384 12815.05 X YV 192 -0.32 287515 -0.23 285510 -0.16 284507 -0.10 282499 -0.30 281498 -0.48 276490 -0.26 275490 -0.56 272482 -0.32 271479 -0.37 265471 -0.11 260464 -0.11 256459 -0.18 257459 -0.04 255460 -0.08 254458 -0.02 250449 -0.09 245446 -0.02 241439 -0.15 240437 -0.08 239438 0.09 1.50 0.22 289523 0.12 288522 0.18 286515 0.29 283501 0.04 280493 0.17 279493 1.61 278493 1.59 277490 0.42 274488 1.00 273488 0. 97270480 0.35 269479 0.11 268478 0.49 267477 0.23 266477 1.07 263467 1.52 261466 0.26 264470 0.93 262468 0.38 259462 0.10 258461 1.39 252455 0.12 253454 0.01 251449 1.65 249449 2.33 242441 0.81 248448 0.15 247447 0.06 246447 1.21 244443 0.10 243441 0.94 238434 B-V NX 224 15.61-0.17 171 17.371.40 146 18.22-0.04 115 18.570.08 160 16.850.00 146 15.600.13 215 16.44-0.14 135 18.31-0.34 166 17.72-0.06 270 18.39-0.03 115 18.11-0.15 233 15.461.41 277 17.79-0.17 185 16.44-0.10 128 17.241.89 228 18.25-0.31 198 16.99-0.16 175 17.050.02 255 17.001.13 241 15.241.39 270 18.130.01 206 17.720.82 130 17.690.02 141 16.840.04 176 18.290.10 236 17.721.23 266 17.80-0.23 195 17.940.18 200 15.25-0.15 178 15.480.00 290 15.26-0.10 300 17.500.60 119 18.100.52 158 18.090.41 248 17.85-0.10 303 16.40-0.13 137 18.41-0.26 187 14.920.09 211 18.11-0.86 56 14.790.38 82 14.880.06 93 15.190.12 66 16.131.55 72 17.42-0.13 37 18.18-0.15 94 18.00-0.67 66 18.170.60 93 17.27-0.20 83 16.790.00 63 17.44-0.05 36 17.77-0.33 44 16.700.46 Y VB-V E. NGC 1855 (Center: 361,171)

X V B-v N B-V N B-V 192 152 18.36 1.95 61 316 279 18.12 22 121 399 226 16.84 -0.10 196 199 17.28 1.22 62 317 86 16.57 99 122 403 183 16.77 0.05 197 144 16.92 1.65 63 316 16 18.13 54 123 405 36 17.01 1.75 201 238 17.39 2.11 64 318 129 15.43 08 124 408 152 17.97 1.22 208 177 15.91 1.40 65 318 161 14.62 50 125 413 47 17.80 0.95 211 121 15.81 1.44 66 320 262 16.93 22 126 415 208 17.74 -0.15 217 147 16.98 0.83 67 322 148 17.45 -0.35 127 416 194 17.81 0.08 219 251 17.88 0.38 68 324 243 16.36 1.25 128 416 316 17.37 0.19 218 176 16.89 0.22 69 327 69 17.56 -0.08 129 417 244 17.32 0.03 220 206 17.35 0.50 70 328 157 15.99 0.19 130 418 265 17.53 0.89 220 133 17.48 1.69 71 327 215 16.80 -0.05 131 420 221 17.68 -0.26 229 138 17.37 0.83 72 329 232 17.49 1.32 132 421 173 15.91 1.25 230 275 17.47 -0.30 73 331 182 15.93 2.32 133 425 165 16.04 1.99 232 211 18.03 -0.07 74 332 294 17.60 -0.16 134 425 331 17.30 -0.06 234 88 13.78 0.11 75 336 310 16.03 1.40 135 427 37 18.01 -0.34 235 122 17.66 0.95 76 337 263 17.34 -0.11 136 427 245 16. 91 0.07 243 50 15.61 -0.09 77 339 156 16.06 0.53 137 429 153 16.56 0.29 243 190 17.68 0.19 78 340 204 14.99 0.29 138 427 87 15.22 1.48 244 260 18.32 0.18 79 342 254 16.58 1.19 139 433 193 17.24 0.01 245 137 17.57 0.58 80 343 130 16.49 0.59 140 434 141 16.39 0.08 247 81 16.58 0.10 81 346 277 16.18 0.14 141 439 247 17.72 0.22 250 277 18.00 90 82 345 173 14.56 -0.05 142 439 216 18.13 0.50 251 299 16.82 03 83 349 144 14.59 0.39 143 441 53 16.84 03 251 39 17.89 22 84 349 24 17.13 -0.05 144 442 114 15.61 57 252 199 18.00 63 85 352 121 17.18 0.73 145 446 65 17.76 37 252 65 16.15 06 86 352 50 18.19 0.44 146 447 182 18.05 81 252 225 16.34 0.07 87 354 313 16.18 0.34 147 448 210 17.72 13 253 209 17.57 0.30 88 353 86 16.59 1.44 148 448 313 16.97 50 254 313 17.90 1.67 89 355 154 14.67 0.44 149 449 134 17.89 04 258 25 17.89 -0.02 90 356 238 17.14 -0.45 150 452 244 17.61 0.15 260 133 16.31 0.02 91 357 136 15.32 1.54 151 453 261 17.00 -0.10 260 154 15.23 -0.03 92 358 167 15.36 -0.18 152 458 82 17.44 0.10 261 179 16.62 0.20 93 359 268 14.84 0.34 153 459 166 17.29 -0.11 261 79 17.81 0.75 94 362 291 18.03 -0.09 154 464 288 17.60 0.71 262 313 18.37 0.64 95 362 327 14.26 0.17 155 466 114 16.61 14 267 165 17.71 2.26 96 363 123 17.92 0.84 156 466 138 17.81 70 269 228 18.28 -0.08 97 364 227 16.29 -0.08 157 470 32 16.21 05 268 307 16.95 0.95 98 365 189 16.16 0.11 158 471 307 16.67 37 271 114 16.26 0.04 99 364 77 16.69 0.24 159 474 48 15.95 40 280 172 17.15 0.04 100 371 270 16.89 0.01 160 475 218 17.77 17 280 74 18.23 05 101 372 204 15.99 69 161 477 265 17.30 17 281 312 16.68 08 102 373 41 18.08 00 162 479 69 17.65 0.91 284 209 15.44 35 103 374 71 15.81 01 163 479 277 17.65 -0.02 284 279 16.01 17 104 374 158 15.50 57 164 479 175 16.90 1.33 291 83 16.86 1.42 105 375 186 15.85 10 165 480 129 17.99 0.03 290 129 16.39 1.54 106 377 145 15.64 0.95 166 482 209 17.24 1.56 291 66 15.60 1.41 107 379 59 18.10 -0.28 167 485 184 18.09 -0.06 292 262 18.09 -0.06 108 383 169 14.19 0.43 168 488 138 17.58 -0.05 293 188 17.13 0.61 109 383 50 18.08 0.51 169 489 251 17.55 0.05 300 232 18.61 0.33 110 384 260 15.64 0.00 170 491 194 17.72 -0.12 302 166 14.05 -0.12 111 384 196 17.08 0.53 171 4 92 258 17.89 0.17 304 121 17.37 0.49 112 387 209 17.94 -0.04 172 496 119 17.42 1.26 305 215 16.83 64 113 387 300 15.16 0.03 173 495 82 15.67 -0.07 306 205 17.76 09 114 388 146 17.26 0.08 174 501 273 17.42 0.07 307 69 17.28 03 115 392 337 14.41 0.17 175 502 164 15.91 1.35 308 230 17.13 62 116 395 158 15.50 1.18 176 503 215 17.16 -0.12 310 33 18.25 0.25 117 394 130 17.32 0.24 177 517 136 17.22 -0.14 311 323 18.10 1.77 118 396 204 19.07 -0.81 178 525 156 16.29 0.04 312 184 14.76 0.23 119 396 242 16.68 0.69 179 535 141 17.87 1.63 315 203 17.14 -0.05 120 399 75 17.57 0.31 180 537 197 17.83 1.83

193

X Y V B-V N X Y V B-V N X Y V B-V 106 177 16.80 1.17 57 239 176 14.71 1.55 113 299 180 17.71 0.70 112 129 17.67 1.46 58 243 121 18.06 0.15 114 301 321 17.89 2.20 125 167 16.81 -0.02 59 244 189 17.93 -0.02 115 303 329 17.71 ■0.09 125 174 16.84 2.11 60 248 273 17.28 0.55 116 305 259 17.69 0.91 128 242 16.40 0.84 61 249 172 16.09 1.52 117 305 24 17.97 1.10 130 269 17.02 0.24 62 251 233 17.64 1.03 118 305 193 17.58 0.14 134 84 17.76 0.13 63 251 216 16.52 1.22 119 306 5 14.88 1.69 142 194 17.26 1.46 64 252 151 16.92 1.10 120 306 175 17.51 1.08 143 152 14.53 0.68 65 252 142 17.73 2.26 121 308 323 18.07 0.28 144 114 16.07 -0.12 66 254 258 17.57 0.76 122 310 116 17.91 0.47 144 209 17.31 0.96 67 255 46 17.74 1.48 123 312 234 16.56 1.38 149 68 16.33 1.60 68 256 174 17.14 1.15 124 311 200 17.83 1.26 153 116 17.24 1.71 69 257 281 16.95 0.08 125 313 225 17.73 1.33 153 256 17.21 1.07 70 257 233 18.32 -0.06 126 314 270 17.87 1.46 156 36 18.14 0.89 71 257 159 16.87 0.47 127 314 155 17.74 ■0.01 160 189 17.89 1.05 72 258 128 18.17 0.08 128 321 209 18.21 1.98 164 141 17.91 0.03 73 259 152 18.02 0.25 129 321 175 15.03 1.57 165 306 17.97 -0.09 74 260 324 15.83 0.10 130 324 106 18.19 0.62 165 150 17.56 1.04 75 261 201 17.53 0.13 131 326 22 15.68 0.72 169 45 16.57 0.56 76 264 193 18.31 0.49 132 329 61 17.54 1.53 172 144 17.88 0.92 77 264 164 15.81 0.37 133 329 213 17.22 1.25 172 224 18.14 1.58 78 263 22 17.98 -0.13 134 329 267 16.91 1.41 176 193 16.67 1.81 79 265 215 18.17 0.22 135 331 319 17.75 ■0.05 176 273 18.07 1.62 80 266 78 17.92 1.60 136 334 282 17.93 •0.05 178 76 16.99 1.82 81 268 175 17.70 0.66 137 336 38 17.06 ■0.08 179 86 18.59 -0.48 82 268 144 19.09 -0.29 138 337 129 16.98 0.13 179 249 16.89 1.77 83 269 151 17.96 0.20 139 337 305 16.41 •0.10 182 295 15.82 0.61 84 270 166 17.96 -0.28 140 341 252 16.23 0.03 183 108 17.17 -0.04 85 270 4 17.80 0.92 141 342 32 17.97 1.61 185 126 17.28 1.36 86 270 182 17.81 1.82 142 343 194 14.22 0.01 186 222 17.42 0.14 87 274 292 18.14 0.25 143 350 69 18.22 ■0.06 187 146 18.30 1.70 88 274 236 17.48 0.28 144 352 315 15.92 1.27 187 318 17.45 0.10 89 274 31 17.81 1.43 145 353 239 18.16 ■0.06 188 193 17.01 0.02 90 274 154 17.27 1.28 146 354 228 18.24 0.57 194 116 18.01 0.73 91 276 18 16.60 -0.08 147 356 285 16.59 1.22 203 267 16.62 -0.07 92 279 178 17.13 1.00 148 357 26 17.41 0.86 206 308 16.82 1.65 93 280 264 18.14 0.18 149 370 189 16.73 0.03 207 248 18.07 0.77 94 281 25 18.02 0.80 150 378 159 17.75 1.38 208 183 18.08 0.41 95 282 188 17.23 0.52 151 380 221 17.84 0.92 209 195 18.31 ,1.22 96 282 148 17.68 1.50 152 381 292 17.89 1.17 211 292 18.06 0.20 97 284 126 17.41 0.81 153 392 281 16.53 0.88 214 60 17.56 0.25 98 284 156 17.51 0.54 154 394 176 17.58 1.35 217 275 18.02 0.75 99 285 250 17.96 0.09 155 395 234 17.98 1.04 217 49 16.29 -0.02 100 287 138 18.31 0.99 156 395 194 17.52 1.25 219 12 17.57 1.23 101 288 10 18.03 1.37 157 397 220 16.12 1.20 222 289 17.29 1.52 102 288 217 17.86 0.16 158 398 270 17.93 1.13 223 85 17.69 0.94 103 288 241 17.35 -0.01 159 400 188 18.03 0.26 223 197 18.32 0.31 104 289 197 16.60 1.59 160 403 47 17.90 1.05 224 170 16.41 0.19 105 289 83 16.48 0.96 161 403 109 18.21 1.52 228 161 18.00 1.23 106 291 146 17.06 0.57 162 426 164 18.13 0.92 232 197 17.44 0.19 107 291 62 18.02 0.83 163 428 172 17.31 1.26 232 127 16.55 1.92 108 291 184 17.94 -0.48 164 431 156 17.02 1.83 236 293 17.08 0.21 109 293 158 16.73 1.52 165 435 184 18.19 1.18 237 242 17.30 1.73 110 294 309 16.70 1.08 166 435 152 17.74 1.04 238 159 17.64 0.05 111 296 169 17.73 0.85 167 438 118 17.35 0.22 238 148 17.19 0.37 112 297 230 17.41 1.43

194

N B-V B-V N B-V 1 181 208 17.47 -0.05 42 297 146 15.91 -0.10 83 380 196 16.39 0.19 2 182 166 17.82 0.05 43 299 260 17.78 -0.12 84 381 295 17.98 0.05 3 183 83 17.11 -0.04 44 301 207 15.28 -0.13 85 385 229 16.47 -0.07 4 191 113 16.40 -0.06 45 302 59 14.94 -0.12 86 388 260 18.04 0.77 5 192 127 16.52 -0.10 46 303 170 17.19 1.60 87 390 271 17.63 0.63 6 198 248 17.29 -0.14 47 308 146 17.24 -0.16 88 391 13 14.24 -0.13 7 203 205 17.59 -0.19 48 310 39 15.56 -0.12 89 392 175 15.23 -0.0 9 8 206 230 15.48 -0.12 49 311 211 16.99 -0.03 90 394 118 15.34 -0.08 9 212 188 16.28 -0.08 50 315 193 13.93 -0.11 91 407 242 15.83 -0.11 10 214 142 13.26 -0.05 51 316 284 16.34 -0.02 92 409 301 16.65 0.00 11 224 190 16.93 -0.03 52 317 168 16.26 0.25 93 412 117 16.01 -0.12 12 224 29 14.28 12 53 319 128 15.62 -0.10 94 413 84 18.00 -0.42 13 226 262 18.07 04 54 319 180 16.97 -0.09 95 414 229 15.12 -0.11 14 228 162 17.13 01 55 321 142 14.20 0.36 96 417 56 17.14 -0.12 15 233 148 17.96 24 56 329 295 17.07 -0.09 97 419 134 17.09 -0.09 16 236 173 17.84 16 57 330 119 16.48 -0.08 98 424 232 16.96 0.14 17 240 159 17.78 22 58 335 187 15.23 -0.09 99 424 272 17.66 0.93 18 246 212 16.03 11 59 337 148 13.71 -1.20 100 427 120 16.45 0.02 19 252 286 16.14 -0.12 60 339 12 16.43 -0.18 101 427 211 17.72 -0.08 20 255 64 17.04 -0.05 61 339 65 15.53 -0.13 102 440 266 15.90 -0.12 21 257 262 17.82 0.88 62 339 207 16.22 -0.12 103 440 248 16.66 0.88 22 260 173 17.73 -0.33 63 345 125 15.62 -0.10 104 442 155 17.62 1.87 23 261 232 17.42 -0.08 64 347 192 16.90 -0.08 105 447 142 16.67 -0.09 24 261 109 16.83 -0.12 65 348 88 17.45 -0.08 106 454 21 17.86 0.00 25 261 162 16.21 26 66 352 120 14.69 0.07 107 455 134 16.51 -0.19 26 262 37 16.21 17 67 352 296 16.36 -0.15 108 458 227 15.53 -0.13 27 265 201 16.94 03 68 353 9 16.62 -0.08 109 4 65 189 15.52 -0.09 28 271 274 17.76 08 69 355 228 17.04 0.02 110 467 148 15.54 -0.03 29 272 289 16.44 06 70 356 318 16.42 -0.09 111 467 200 16.15 -0.05 30 274 19 15.39 -0.13 71 357 147 15.98 -1.76 112 470 119 15.81 -0.17 31 275 108 17.29 -0.06 72 3 62 178 15.99 0.04 113 473 259 16.52 -0.13 32 279 163 17.45 0.30 73 363 287 17.56 0.20 114 474 161 16.63 -0.11 33 280 205 15.94 -0.10 74 364 247 16.55 -0.07 115 480 60 13.45 1.79 34 283 174 17.14 0.02 75 366 58 17.22 0.49 116 489 208 17.06 -0.10 35 284 150 16.04 -0.12 76 369 227 16.64 -0.16 117 491 230 15.33 -0.14 36 289 184 16.01 -0.10 77 370 129 16.19 0.23 118 493 172 17.76 -0.05 37 288 124 18.32 0.25 78 371 161 15.18 0.24 119 496 226 15.91 -0.03 38 292 83 13.62 -0.09 79 371 3 17.78 -0.12 120 508 130 17.26 -0.14 39 292 44 16.88 -0.17 80 372 191 16.31 -0.14 121 509 188 16.29 -0.13 40 295 221 17.05 0.07 81 374 110 13.34 -0.09 41 297 272 15.49 0.04 82 377 275 17.32 0.79

195

© American Astronomical Society • Provided by the NASA Astrophysics Data System 19 91ApJS. . .76. .185E 47 315244 48 315285 46 31381 45 31222 44 310139 43 30953 41 307293 42 308123 40 307172 39 302187 38 298213 37 298118 35 294274 34 293157 36 2979 29 282194 33 291128 32 290146 30 28979 28 279207 27 27737 26 274145 31 290170 25 27466 24 269250 23 267223 22 267162 21 265107 20 263211 19 262173 18 261196 17 25912 16 25866 14 252193 15 257273 13 25138 12 250175 11 24119 10 240189 N XY 8 235141 5 216185 3 211117 2 200133 9 233269 7 222129 6 216214 4 214146 1 181150 231 219 210 203 205 243 199 163 142 © American Astronomical Society • Provided by theNASA Astrophysics Data System 48 16.05 17.99 17.56 16.89 16.31 17.01 -0.14 17.51 -0.08 15.85 -0.09 13.02 1.72 15.74 -0.07 17.42 0.53 16.33 -0.19 17.09 0.31 14.34 0.01 14.45 -0.10 16.07 -0.12 14.98 -0.15 15.62 1.23 17.00 1.54 16.56 -0.04 13.60 1.82 18.46 -0.24 15.77 -0.13 16.83 -0.15 16.80 -0.17 16.28 -0.28 16.97 -0.14 17.62 0.07 16.02 -0.11 16.39 -0.16 17.05 1.31 17.98 0.66 17.66 0.09 17.93 0.09 17.26 -0.10 15.31 -0.15 17.65 -0.03 18.47 0.17 16.38 -0.16 17.59 1.24 17.48 -0.21 17.24 -0.14 16.57 1.47 16.56 1.32 17.15 -0.14 17.86 -0.18 15.86 -0.14 16.88 -0.16 17.83 -0.04 17.64 -0.06 16.56 -0.17 17.50 0.83 17.93 -0.11 v V B-V -0.07 0.21 0.28 0.14 0.17 B-V 10 96 379266 95 379145 94 37978 91 371221 89 370106 88 36957 93 375162 92 373129 90 369116 87 368175 86 36714 85 363189 84 363156 83 36047 82 360243 81 359110 80 359276 79 35933 78 356120 77 3549 76 35487 75 352215 74 35163 73 350251 72 350297 71 351144 70 348192 59 33372 69 344163 68 34476 58 332170 67 343141 66 3415 65 340274 62 335190 57 331204 55 33087 64 338129 63 33612 56 330144 54 327257 53 327115 51 323248 61 334115 60 334158 52 323126 50 317205 49 316307 8 9 7 6 N XY I. NGC2100(Center:350,149) H. NGC2004(Center:350,142) 243 250 242 236 235 237 210 113 256 197 196 13.02 0.32 15.54 -0.19 17.74 -0.67 15.36 -0.36 17.21 -0.20 15.08 -0.15 15.18 -0.15 17.05 -0.29 17.09 -0.04 15.77 -0.03 16.61 -0.04 14.73 -0.05 13.50 1.94 16.81 -0.12 16.34 -0.16 17.49 0.09 14.48 -0.17 16.33 -0.16 14.76 -0.14 14.99 -0.20 15.33 -0.04 12.67 1.40 15.50 -0.16 14.93 0.72 12.48 0.57 15.79 0.18 16.08 -0.17 16.63 0.10 15.85 -0.09 14.15 0.91 16.89 -0.24 15.21 -0.22 14.78 -0.26 16.80 -0.23 15.98 -0.08 16.15 -0.13 15.26 -0.04 14.05 -0.14 14.87 -0.59 17.31 -0.07 15.85 -0.21 17.22 0.18 13.33 1.89 15.96 0.01 14.31 -0.07 17.77 -0.16 15.21 -0.19 15.29 1.37 16.10 17.23 17.21 17.16 15.97 V B-V 0.38 0.11 0.16 0.05 0.14 B-V 14 15 13 11 12 143 523148 142 513172 141 50570 140 499192 139 49166 138 484199 137 483131 136 475177 135 475162 133 46835 134 468259 132 468140 131 462213 130 459192 129 45811 128 45146 127 450105 126 450241 125 44863 119 417280 124 446206 123 443159 122 437256 120 430133 118 417204 117 416145 121 43730 116 415176 115 414229 114 413268 113 407116 112 405254 111 40513 110 404167 109 40059 107 398230 108 398207 106 395150 105 393184 104 391116 103 389172 102 387312 101 38737 100 384285 99 383113 98 3833 97 381199 N XY 259 253 252 250 252 226 145 29 39 84 15.79 16.92 17.83 14.72 16.68 17.03 1.22 14.83 -0.17 18.05 -0.22 17.52 -0.21 17.92 -0.02 17.37 1.29 17.59 0.60 17.77 -0.05 15.83 -0.19 18.10 0.07 16.14 -0.14 12.15 0.02 17.63 -0.08 18.09 -0.08 16.28 -0.14 16.33 0.52 18.36 0.04 16.93 1.14 18.32 -0.03 17.40 -0.17 16.28 -0.18 15.96 -0.15 16.40 -0.15 15.87 -0.21 15.81 -0.18 12.50 -0.01 16.49 -0.12 17.47 -0.12 16.45 -0.10 17.57 0.02 14.70 -0.13 15.54 -0.16 15.81 -0.09 17.47 -0.24 13.20 1.75 16.76 -0.13 17.24 0.20 15.37 -0.03 15.63 -0.04 16.95 0.10 13.59 -0.13 17.72 1.03 17.89 -0.09 16.43 -0.15 17.74 0.19 17.00 -0.28 15.67 -0.17 V B-V -0.10 0.06 0.30 1.99 0.09 B-V 19 91ApJS. . .76. .185E 13 11 10 24 12 55 54 52 51 50 29 28 27 26 25 23 21 20 53 39 38 36 35 30 22 19 18 17 16 49 48 46 45 43 42 40 37 34 33 32 31 47 44 41 5 8 7 4 3 2 1 9 6 214 281 299 293 289 283 282 281 281 271 269 260 260 212 205 205 344 339 339 337 304 300 277 268 208 188 186 178 173 347 340 337 336 326 326 325 324 322 320 320 319 316 313 312 308 324 307 301 301 195 184 170 170 124 201 246 154 113 299 173 105 179 164 137 298 312 207 132 249 210 263 273 294 206 186 165 164 106 130 172 © American Astronomical Society • Provided by theNASA Astrophysics Data System 180 185 165 167 118 133 158 153 106 144 132 53 29 18 23 23 18 57 10 40 17 81 42 78 50 60 16.18 14.30 13.16 13.60 17.67 18.11 16.14 16.08 16.26 14.47 16.26 15.33 17.78 16.72 18.04 17.03 17.52 15.92 17.26 15.22 16.34 16.09 12.88 17.62 16.07 13.81 12.29 17.23 17.44 13.50 16.94 18.18 12.68 16.10 17.45 17.25 13.81 17.94 15.85 16.81 18.23 19.44 19.58 19.00 19.67 18.73 19.05 19.64 19.11 17.38 18.10 19.47 18.06 -0.37 -0.10 -0.26 -0.79 -0.05 -0.03 -0.03 -0.03 -0.07 2.31 0.14 0.04 0.29 0.05 0.61 0.85 0.00 0.78 0.98 0.10 1.52 1.11 0.88 1.60 B-V B-V 27 18 10 23 17 24 10 25 06 13 15 13 14 04 33 09 08 08 18 45 09 80 02 01 07 01 60 48 06 86 57 95 93 89 88 87 85 84 83 82 80 79 77 74 70 59 58 56 94 92 90 81 78 76 75 73 72 71 91 67 64 69 68 66 65 63 62 61 60 26 25 24 23 22 20 21 19 18 17 16 15 14 J. NGC2156(Center:347,148) I. NGC2100—Continued 398 411 406 402 399 397 394 391 409 400 396 391 392 388 387 382 380 379 376 375 359 357 355 354 391 376 374 374 372 371 364 363 354 352 353 353 348 349 347 349 240 215 234 234 234 233 231 231 223 220 240 229 220 126 272 257 245 105 202 151 136 161 282 293 235 204 180 278 272 206 108 134 141 120 188 142 154 221 175 186 156 113 260 134 225 221 106 123 23 74 20 77 35 83 59 61 48 42 77 75 31 40 81 76 1 9 197 15.94 15.56 16.96 13.66 17.45 15.31 12.96 18.03 15.97 16.67 18.10 13.81 14.06 18.65 16.85 17.00 17.23 17.30 12.21 16.21 16.49 14.46 17.07 14.39 15.94 16.40 18.39 18.29 14.41 16.84 16.08 14.63 12.83 17.78 17.20 16.67 15.09 12.03 15.27 16.14 19.40 16.49 17.48 19.24 18.31 18.09 18.81 19.60 19.00 18.34 19.26 19.68 18.44 -0.06 -0.04 -0.06 -0.28 -0.08 -0.01 -0.02 -0.14 -0.02 -0.04 0.97 0.01 1.55 1.77 2.12 0.05 0.14 0.18 0.00 1.64 1.68 0.00 0.02 0.09 0.18 0.10 0.26 0.05 0.23 0.35 0.08 1.34 0.36 0.76 0.81 0.08 0.20 0.17 0.22 0.51 0.19 0.01 0.58 B-v 1.75 0.03 1.04 0.09 0.87 0.00 0.20 0.80 0.06 0.50 B-V 135 134 133 132 131 130 129 128 126 122 119 118 117 116 109 127 125 124 123 121 120 115 114 113 112 110 108 107 111 106 105 104 103 102 101 100 39 29 38 37 36 35 34 33 27 32 31 30 28 98 99 97 96 N 258 258 255 252 256 253 252 247 245 244 243 241 242 523 522 510 507 504 502 515 459 4 95 490 488 474 470 466 461 456 451 452 451 448 442 434 432 423 491 485 474 473 450 451 442 431 422 419 416 414 422 417 416 411 268 112 205 194 239 274 220 257 199 188 151 154 181 107 126 212 165 282 231 285 191 141 194 155 178 148 112 274 136 227 167 113 209 174 274 150 116 174 179 184 242 56 57 73 59 31 75 21 94 50 91 61 1 18.70 19.67 19.59 19.73 19.44 18.83 19.99 17.37 19.50 17.53 19.13 19.49 15.90 15.21 17.31 15.23 17.14 17.31 17.11 18.43 18.39 18.10 16.84 18.28 18.21 17.14 17.57 17.63 15.26 13.81 17.94 17.16 13.74 17.40 17.74 15.87 13.81 15.90 17.11 17.73 17.61 15.37 13.75 17.68 15.94 16.63 15.52 14.97 17.05 15.20 13.66 13.89 16.39 -0.09 -0.11 -0.04 -0.05 -0.15 -0.01 -0.16 -0.13 -0.01 -0.39 -0.19 -0.06 -0.34 1.47 0.84 0.78 1.18 1.04 1.32 0.09 0.15 0.03 0.69 0.24 0.62 0.02 0.15 0.60 1.37 1.52 0.16 1.95 0.44 0.27 1.83 0.49 1.04 0.44 0.11 0.09 0.01 0.54 0.47 0.04 0.00 1.14 0.08 0.07 0.37 0.10 0.01 0.05 0.13 B-V B-v J. NGC 2156—Continued

X B-v N B-V N B-V 259 84 19.53 1.11 100 324 294 17.74 -0.01 160 378 322 19.63 -0.15 262 277 19.90 0.11 101 324 152 16.19 -0.10 161 378 139 17.10 -0.02 262 152 18.62 -0.23 102 325 78 19.45 0.09 162 379 146 17.12 0.03 264 136 17.99 0.16 103 327 15 19.76 2.03 163 380 235 19.41 0.61 265 55 19.09 0.18 104 326 208 19.61 -0.08 164 380 170 16.81 -0.19 265 10 18.76 -0.06 105 326 143 15.59 1.10 165 382 192 19.78 -0.08 266 178 16.03 0.04 106 328 62 19.01 0.10 166 383 35 18.73 -0.11 269 218 18.96 0.80 107 328 276 19.80 0.16 167 384 307 19.10 -0.20 271 205 19.06 0.07 108 329 172 17.35 0.02 168 384 30 18.88 0.17 271 290 19.63 0.35 109 332 197 18.88 0.14 169 385 161 18.37 1.23 272 170 19.68 0.72 110 333 179 18.26 -0.04 170 385 55 18.89 0.03 272 142 17.81 -0.21 111 334 216 19.01 0.11 171 385 111 18.67 -0.12 274 69 19.20 -0.16 112 335 262 19.56 0.11 172 387 135 17.28 -0.11 274 272 19.56 0.05 113 335 108 16.80 0.01 173 390 118 18.31 0.07 275 237 19.78 0.68 114 336 125 17.00 0.10 174 390 108 17.72 0.00 277 175 18.91 0.07 115 337 76 15.97 1.15 175 393 222 18.58 0.22 281 12 19.11 -0.16 116 338 49 18.08 0.00 176 393 35 18.94 1.02 282 19 19.72 0.56 117 339 115 17.11 0.00 177 394 215 18.69 0.20 282 143 17.73 -0.04 118 339 210 18.25 -0.03 178 395 57 19.20 0.90 283 111 18.93 0.28 119 340 147 14.18 0.15 179 395 194 19.64 0.01 283 120 17.54 0.01 120 341 37 18.52 0.30 180 396 183 16.74 0.03 287 210 18.88 -0.18 121 342 306 19.77 0.84 181 398 24 16.66 1.23 288 129 17.05 0.09 122 343 127 17.03 0.02 182 398 151 15.72 0.86 288 71 17.21 0.00 123 343 230 19.55 0.03 183 403 138 17.63 05 288 150 19.32 -0.06 124 344 173 18.47 0.17 184 403 293 19.76 05 289 3 18.76 12 125 344 23 17.17 -0.05 185 405 87 17.18 42 291 105 18.44 03 126 348 69 18.93 -0.09 186 405 214 16.73 10 291 193 18.28 17 127 348 196 18.87 0.15 187 405 165 18.28 01 291 118 17.63 05 128 349 267 18.83 1.51 188 406 263 19.53 0.04 294 147 19.19 13 129 349 264 18.40 -0.28 189 410 32 17.41 -0.04 294 230 19.18 0.05 130 349 149 14.79 0.00 190 411 191 20.16 0.78 299 205 17.93 -0.06 131 351 42 19.32 0.08 191 411 142 18.41 0.80 299 136 19.40 0.40 132 352 193 19. 91 0.28 192 411 182 19.71 -0.03 300 277 18.79 0.59 133 356 111 19.00 0.23 193 413 16 19.57 0.95 302 156 18.51 0.02 134 356 47 18.25 0.13 194 413 205 18.35 -0.03 303 312 18.29 -0.07 135 358 85 18.38 0.01 195 414 158 18.61 -0.13 304 74 17.71 0.01 136 360 211 16. 95 1.36 196 415 210 19.11 0.69 304 45 19.94 0.86 137 360 230 17.49 0.05 197 415 46 14.74 0.96 305 13 18.99 1.08 138 362 164 15.14 0.24 198 417 108 18.71 -0.04 304 295 19.69 0.26 139 363 220 17.02 0.00 199 419 241 18.43 -0.02 305 116 14.88 0.19 140 364 118 18.03 -0.09 200 422 212 18.12 1.70 304 222 19.17 0.94 141 362 151 15.85 0.44 201 421 155 18.39 0.95 305 83 18.92 0.01 142 365 261 18.24 -0.11 202 422 138 19.25 0.38 306 138 18.27 -0.03 143 365 30 19.02 -0.39 203 422 19 18.79 0.66 306 245 19.37 -0.01 144 366 172 16.86 0.01 204 424 64 18.77 -0.12 307 170 17.90 0.04 145 366 37 17.21 1.33 205 428 2 19.35 0.17 308 129 17.60 -0.13 146 367 78 17.02 -0.06 206 429 246 18.47 0.67 310 198 18.00 0.14 147 366 138 18.04 -0.31 207 430 265 19.25 1.03 312 17 19.69 -0.11 148 368 55 18.52 -0.03 208 432 82 19. 62 0.69 313 44 19.19 0.04 149 369 132 16.63 -0.06 209 433 166 19.24 1.04 314 88 18.27 -0.03 150 369 204 20.02 -0.02 210 433 49 16.84 -0.05 315 159 16.76 -0.08 151 370 247 19.26 0.82 211 434 221 19.11 0.78 315 300 17.76 -0.08 152 371 112 18.94 -0.10 212 436 33 19.45 0.85 315 115 18.98 -0.49 153 371 218 17.38 -0.03 213 437 235 19.20 1.01 317 207 18.32 -0.08 154 372 229 19.00 -0.06 214 441 163 18.61 -0.06 320 287 17.39 1.75 155 372 105 18.14 -0.09 215 445 125 18. 98 0.91 323 115 18.81 0.31 156 373 188 19.19 0.08 216 445 174 18.57 -0.25 322 126 19.13 -0.22 157 373 161 16.86 -0.01 217 445 232 19.38 0.84 324 18 19.40 -0.07 158 374 285 18.83 1.12 218 445 187 18.82 0.92 324 192 17.19 -0.06 159 377 302 18.85 0.99 219 446 201 19.10 0.19

198

© American Astronomical Society • Provided by the NASA Astrophysics Data System 19 91ApJS. . .76. .185E 38 45 43 40 39 37 36 35 29 48 47 46 44 42 41 34 33 32 28 27 31 30 26 25 24 23 22 20 17 21 19 16 15 14 18 13 12 11 10 226 225 224 223 221 220 222 5 3 2 1 8 7 4 9 6 N 263 261 260 259 259 257 256 254 248 261 249 247 247 247 243 246 242 240 240 238 237 236 236 236 235 225 235 233 233 232 230 229 228 219 218 218 213 212 193 211 209 194 205 195 191 189 185 188 4 67 4 63 457 446 4 60 453 450 222 253 287 130 122 200 160 300 166 131 252 305 272 175 204 193 277 134 183 283 141 216 241 268 196 134 231 201 162 240 206 158 144 136 147 199 © American Astronomical Society • Provided by theNASA Astrophysics Data System 52 29 51 36 22 52 62 74 76 281 242 65 78 197 178 123 91 86 83 18.94 18.36 16. 94 19.08 18.10 18.41 18.97 17.32 16. 97 19.55 18.77 16.11 17.76 19.51 17.34 18.89 16.54 19.55 19.07 18.56 18.37 19. 69 17.40 18.14 18.74 18.44 19.78 18.67 18.23 19.83 18.24 19.28 18.43 17.09 16.48 19.43 19.71 19.79 19.01 19.81 16.92 16.55 18.66 18.82 19.01 19.81 19.35 19.77 17.19 18.41 17.79 18.66 19.51 16.19 17.87 V -0.06 -0.03 -0.19 -0.05 -0.13 -0.06 -0.28 0.02 0.01 0.40 0.14 0.06 1.34 0.00 2.28 0.09 0.05 1.76 0.34 0.34 0.09 1.25 0.10 0.07 0.14 0.19 0.04 0.03 0.96 0.18 0.14 0.02 1.39 0.48 1.27 0.66 1.59 0.04 0.09 0.48 0.79 1.06 0.10 0.51 0.38 0.41 1.32 0.74 0.32 0.01 B-V B-V 34 10 13 07 66 89 88 87 86 85 84 83 96 95 94 93 91 82 81 80 78 92 90 79 77 76 75 70 59 58 57 54 74 73 72 71 55 53 52 51 233 482 232 479 231 474 230 473 228 469 227 469 56 50 229 470 69 68 67 65 49 66 64 63 62 61 60 N K. NGC2157(Center:346,155) J. NGC2156—Continued 315 309 298 296 312 309 309 309 308 308 301 300 291 290 289 289 288 314 306 302 300 300 287 286 285 283 280 279 276 285 283 279 278 275 274 273 273 269 268 265 274 272 271 268 266 265 265 264 . 88 153 205 143 260 194 122 169 221 166 197 148 190 124 306 240 292 258 178 234 144 169 107 200 279 244 176 122 202 132 186 128 236 282 141 149 302 176 254 241 106 150 40 82 51 32 79 165 145 106 69 51 28 89 46 199 15.13 15.65 16.30 18.26 18.18 17.44 18.04 15.02 16.15 16.37 18.41 15.72 18.70 18.59 18.14 17.31 18.59 19.04 19.44 19.25 16.89 18.46 17.17 18.32 18.93 17.24 17.72 16.27 19.64 18.69 19.14 18.82 17.88 16.08 19.86 18.03 17.09 18.44 17.37 19.38 18.99 19.10 17.33 18.65 19.55 19.49 19.58 19.06 19.94 16.18 19.68 19.41 17.78 19.57 19.94 -0.04 -0.55 -0.23 -0.02 -0.12 -0.09 -0.20 -0.03 -0.03 -0.08 0.48 1.58 1.38 0.15 1.38 0.28 0.43 1.29 0.22 0.91 0.14 0.02 0.09 0.15 0.86 0.07 0.03 0.10 0.26 1.07 1.37 0.09 1.39 0.18 0.12 0.10 0.00 0.03 0.40 0.14 0.09 0.12 0.40 0.84 0.07 0.07 0.83 0.00 0.03 0.78 1.13 0.32 0.05 0.13 0.13 B-V B-V 141 144 143 142 140 139 138 136 134 137 135 133 132 131 130 129 128 126 125 127 124 123 122 120 118 113 121 119 117 116 115 114 112 111 110 107 106 105 104 103 102 101 238 237 235 109 108 100 236 234 97 99 98 N N 353 354 348 348 347 345 354 352 350 349 347 343 343 350 342 340 340 337 337 334 324 338 337 333 333 332 331 327 326 324 324 323 319 319 317 316 516 121 505 201 331 331 329 328 328 327 325 324 322 318 318 316 486 57 490 63 487 121 241 202 259 226 128 148 105 325 195 178 159 206 292 219 160 170 144 221 328 231 198 205 244 184 263 123 173 140 178 106 301 320 154 20 84 75 81 87 49 57 25 94 37 45 86 73 69 66 19.19 14.64 15.08 19.21 19.81 14.85 19.87 19.60 19.17 16.26 15.06 17.87 18.43 15.33 16.30 18.83 18.99 17.96 15.51 16.53 16.65 15.68 14.39 19.03 19.88 17.59 19.89 17.67 19.29 18.71 18.99 17.97 17.85 18.16 14.77 17.97 19.44 15.17 19.16 15.52 18.64 18.05 19.16 19.90 16.58 19.96 18.88 17.95 17.91 15.56 19.25 19.92 19.36 -0.03 -0.20 -0.06 -0.53 -0.08 -0.08 -0.08 -0.07 -0.18 1.43 0.30 1.28 0.04 0.33 1.24 0.12 0.96 0.03 0.44 0.23 0.37 0.00 1.80 0.25 0.22 1.91 0.01 0.04 0.01 0.36 0.26 0.12 0.96 0.83 0.23 0.09 0.06 0.07 0.17 0.05 0.22 0.00 0.11 0.51 0.87 0.04 0.13 0.12 0.14 1.10 1.16 0.05 0.16 B-V B-V 19 91ApJS. . .76. .185E 21 20 19 18 17 177 176 16 15 14 13 175 174 173 172 12 11 171 170 169 168 166 10 167 165 164 160 163 162 161 159 158 157 156 155 154 . 153 151 148 150 149 147 146 152 145 5 8 7 2 9 3 1 6 4 N 233 232 231 230 226 221 215 215 214 213 212 206 207 205 205 200 200 199 199 198 197 386 385 384 359 382 380 379 378 377 378 376 376 373 372 371 368 368 368 368 366 365 363 363 361 360 360. 359 358 358 357 356 354 355 © American Astronomical Society • Provided by theNASA Astrophysics Data System 196 147 254 239 224 115 136 153 232 209 148 177 235 124 148 216 130 191 150 244 300 177 195 201 213 232 249 107 188 135 266 164 126 199 309 212 240 217 120 142 156 171 198 75 89 55 68 71 92 47 74 30 39 58 20.10 18.88 19.38 19.54 19.17 19.12 18.09 18.83 19.41 16.06 19.86 20.45 18.60 19.01 17.81 19.99 19.51 19.57 20.48 16.00 20.53 17.63 15.29 17.90 15.09 18.37 16.81 15.74 17.46 19.82 17.25 16.04 17.50 19.10 18.79 17.84 15.34 16.94 17.03 19.76 17.92 18.92 17.08 18.09 17.71 17.15 19.02 18.15 19.12 18.50 14.08 15.24 14.49 17.03 -0.17 -0.03 -0.07 -0.05 -0.03 -0.19 -0.01 -0.08 -0.07 -0.37 -0.07 0.77 0.45 0.02 1.42 0.96 0.10 0.77 1.19 0.06 0.14 0.09 1.05 0.75 0.15 0.34 0.19 0.50 0.55 0.52 1.10 0.86 0.99 0.02 0.14 0.14 1.67 0.10 0.48 0.17 1.48 0.04 0.52 0.04 0.36 0.52 0.06 0.16 0.14 0.01 0.48 0.42 0.58 0.10 B-V B-V 42 39 210 209 41 40 38 37 36 35 34 33 32 208 207 206 31 30 29 28 27 205 204 203 202 201 26 25 24 200 23 22 199 198 197 196 195 194 193 192 191 190 189 188 187 186 185 184 183 182 181 179 178 180 N L. NGC2159(Center:363,147) 265 265 264 257 256 K. NGC2157—Continued 266 257 257 255 254 253 254 251 250 249 249 249 248 245 239 233 420 419 419 418 417 416 415 416 413 413 410 407 405 405 404 403 399 399 399 399 398 402 400 400 397 397 394 393 390 391 390 389 388 183 168 135 232 180 290 144 227 199 188 266 173 125 280 213 ,243 260 301 206 172 160 149 192 218 229 126 176 191 298 159 133 144 226 199 322 256 168 36 23 41 86 58 37 34 50 58 76 60 44 36 91 86 34 61 200 19.31 18.86 19.28 18.57 20.09 19.43 19.39 19.40 19.07 18.17 19.28 19.64 19.63 20.25 17.49 20.58 18.06 18.45 20.11 19.26 18.41 19.36 19.12 19.42 19.26 18.82 18.21 19.57 18.38 18.48 19.53 18.30 17.97 15.60 19.48 18.68 18.69 18.07 19.08 18.58 20.08 18.10 18.97 16.83 16.26 17.91 19.75 18.38 19.08 18.50 18.88 17.92 17.02 18.14 -0.07 -0.11 -0.09 -0.08 -0.13 -0.04 -0.09 -0.34 -0.15 -0.06 -0.02 0.28 0.72 0.13 0.62 0.42 0.37 1.40 0.98 0.92 1.31 1.70 1.03 0.64 0.05 0.08 1.21 0.07 0.17 0.28 0.01 0.05 0.89 1.06 0.07 0.09 0.34 0.13 0.06 1.21 0.38 0.00 0.06 1.07 0.06 0.20 1.12 0.07 B-V B-V 10 25 18 07 61 97 59 58 63 62 57 56 55 54 61 60 53 52 51 50 49 48 241 240 47 46 45 44 239 238 237 236 234 233 232 43 235 231 230 229 228 227 226 225 224 223 222 221 220 219 218 216 217 215 214 213 212 211 N 296 294 293 293 293 289 289 287 287 285 284 280 281 279 278 276 273 273 271 269 266 515 514 507 479 497 488 487 482 474 467 462 461 458 458 456 453 451 445 441 441 441 437 437 433 431 426 426 424 425 423 420 283 252 167 269 309 135 224 311 292 217 281 133 135 149 144 185 207 220 177 241 255 233 170 194 281 207 193 161 182 176 164 171 251 162 229 272 265 280 204 141 187 162 193 218 135 11 33 37 65 76 92 62 20.23 19.42 18.79 18.93 19.62 19.11 18.71 17.40 17.80 19.08 19.28 18.42 18.41 20.30 17.78 18.84 18.93 19.52 19.75 18.13 19.12 19.13 13.48 19.10 17.27 18.57 17.94 19.84 16.99 19.70 16.34 19.70 17.43 18.48 19.10 17.27 19.10 19.16 18.81 16.97 19.17 16.89 20.15 19.18 18.32 18.12 16.14 19.12 17.70 19.23 18.93 19.28 V -0.12 -0.08 -0.08 -0.05 -0.23 -0.12 -0.06 -0.06 -0.10 -0.05 -0.02 -0.22 -0.07 0.40 0.03 0.00 1.10 1.09 0.13 0.80 0.02 0.00 0.01 0.79 0.13 1.00 0.90 1.00 0.23 0.03 0.44 0.05 0.07 0.10 0.06 0.27 0.04 0.10 0.01 1.36 0.02 B-V 0.01 0.01 B-V ,03 ,06 ,08 ,06 ,10 ,24 ,02 ,02 .38 L. NGC 2159—Continued

N B-V N B-V N B-V 64 298 89 19.01 -0.05 124 358 32 20.06 -0.04 184 420 221 19.01 0.98 65 299 271 19.28 0.96 125 360 323 19.32 1.06 185 422 134 18.33 -0.13 66 299 204 20.22 0.08 126 360 64 17.48 -0.03 186 424 217 18.94 -0.08 67 300 75 20.59 -0.32 127 360 163 15.12 0.29 187 425 258 19.93 0.24 68 300 189 17.54 -0.03 128 361 296 19.44 0.26 188 425 158 18.50 -0.11 69 300 153 17.38 -0.04 129 361 223 19.90 0.33 189 425 171 19.64 0.62 70 301 133 16.45 0.99 130 364 144 17.52 0.40 190 426 33 17.95 -0.07 71 303 174 19.43 0.03 131 365 156 15.04 1.30 191 426 71 18.47 0.12 72 304 35 18.92 -0.01 132 367 204 16.73 -0.07 192 426 188 16.62 0.56 73 304 249 15.96 1.30 133 368 249 20.38 0.04 193 426 43 20.21 0.76 74 309 74 19.33 0.04 134 368 177 19.06 -0.05 194 429 89 18.78 0.92 75 311 155 17.45 0.06 135 368 224 19.79 0.27 195 430 123 17.69 -0.04 76 315 14 19.04 -0.03 136 369 122 17.65 -0.36 196 434 63 19.61 0.74 77 315 225 18.65 0.01 137 370 285 19.50 0.01 197 436 189 18.91 0.00 78 316 118 16.35 1.20 138 370 185 19.75 0.73 198 436 151 18.13 -0.07 79 317 304 17.15 1.42 139 372 217 20.08 0.34 199 439 279 19.58 0.76 80 317 151 16.80 -0.01 140 374 324 18.74 -0.08 200 441 243 19.49 1.00 81 318 134 17.60 -0.14 141 377 77 17.53 -0.15 201 444 132 18.79 0.03 82 319 24 20.06 0.17 142 378 14 19.07 0.02 202 444 172 19.08 -0.22 83 320 267 20.27 0.36 143 378 150 18.76 -0.54 203 446 293 20.56 0.63 84 321 143 17.38 -0.28 144 378 44 19.70 0.12 204 447 190 20.34 0.18 85 323 89 20.71 08 145 378 310 19.32 -0.06 205 448 155 18.53 0.11 86 323 170 18.42 03 146 378 164 18.55 0.02 206 450 239 19.03 0.67 87 324 155 18.23 63 147 380 188 18.98 -0.09 207 449 46 20.32 -0.02 88 325 114 16.76 72 148 381 179 18.64 0.22 208 450 59 20.17 -0.20 89 326 165 18.11 62 149 384 245 19.67 -0.01 209 451 183 19.36 0.90 90 327 236 19.85 40 150 385 155 18.15 1.61 210 450 211 19.71 0.02 91 327 202 18.55 -0.14 151 386 80 19.00 -0.17 211 451 167 19.33 0.01 92 326 251 20.06 0.00 152 387 11 17.11 0.80 212 451 224 18.17 -0.05 93 327 179 18.50 0.04 153 388 27 20.07 -0.08 213 451 149 17.92 03 94 326 129 18.46 -0.09 154 389 314. 18.50 0.81 214 453 75 19.14 18 95 327 191 17.06 -0.07 155 390 155 19.31 0.51 215 454 19 18.92 92 96 333 172 18.15 0.15 156 391 252 18.13 1.45 216 455 92 17.00 04 97 333 30 18.56 0.04 157 391 240 20.23 0.20 217 455 290 19.80 93 98 335 147 15.91 1.15 158 392 226 18.31 -0.04 218 455 158 18.59 00 99 336 127 17.65 0.01 159 3 92 171 18.80 0.15 219 456 274 18.79 94 100 336 21 18.75 0.01 160 393 146 17.65 -0.03 220 459 220 18.43 97 101 337 160 15.28 0.73 161 394 115 19.78 0.48 221 459 264 19.78 0.28 102 337 321 18.79 -0.01 162 393 185 18.61 0.05 222 460 138 19.72 0.25 103 338 185 15.35 0.30 163 395 194 19.74 1.11 223 462 246 19.68 -0.18 104 339 56 18.86 0.02 164 395 72 20.35 0.41 224 464 90 19.49 0.51 105 340 92 19.05 -0.06 165 399 129 17.74 -0.14 225 465 156 19.60 0.28 106 340 210 19.65 0.15 166 400 322 19.50 0.33 226 470 275 17.84 1.15 107 342 226 18.17 0.,83 167 401 305 20.12 0.17 227 474 251 16.76 0.01 108 342 138 17.32 ,01 168 400 91 19.83 -0.07 228 475 50 17.09 -0.04 109 343 197 19.74 ,23 169 403 186 19.77 -0.18 229 475 140 17.76 -0.06 110 344 113 18.40 ,11 170 403 154 19.44 0.83 230 478 70 19.23 1.08 111 344 123 18.55 ,03 171 405 117 19.33 0.20 231 479 27 19.91 0.55 112 344 286 18.45 0.01 172 406 196 20.06 0.05 232 480 158 18.52 1.13 113 346 63 19.11 0.82 173 407 139 20.21 -0.22 233 484 232 14.43 0.59 114 348 186 18.75 -0.03 174 410 84 18.79 -0.01 234 484 214 18.94 -0.20 115 348 235 16.85 -0.01 175 410 159 20.66 -0.04 235 484 42 19.91 20 116 349 161 16.87 -0.38 176 411 241 17.19 -0.05 236 485 121 16.57 12 117 349 268 20.18 0.26 177 411 58 19.10 1.13 237 488 200 19.13 79 118 351 250 18.75 0.85 178 412 149 18.46 -0.06 238 489 49 20.03 25 119 354 204 19.01 -0.06 179 414 178 18.81 -0.03 239 495 228 19.50 69 120 355 177 17.42 0.15 180 414 126 17.75 -0.07 240 497 243 19.39 00 121 356 128 17.08 0.56 181 414 12 18.96 0.06 241 497 71 17.96 12 122 358 287 20.24 0.63 182 415 144 18.67 0.16 242 500 123 19.61 0.92 123 358 138 15.92 0.08 183 416 92 18.37 0.06 243 500 155 18.08 -0.05

201

© American Astronomical Society • Provided by the NASA Astrophysics Data System 19 91ApJS. . .76. .185E 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 18 19 17 16 15 14 11 13 12 248 511152 247 507 245 506 10 246 507 244 505 5 3 2 8 1 7 4 9 6 N 240 235 210 132 232 185 203 186 200 121 193 219 184 185 321 317 316 312 310 310 309 306 297 296 295 291 302 295 290 285 275 283 278 276 275 273 272 266 260 255 252 250 248 240 239 237 235 225 215 237 222 251 174 119 200 272 174 233 238 145 229 256 160 204 292 216 © American Astronomical Society • Provided by theNASA Astrophysics Data System 175 200 191* 297 209 272 242 208 278 158 148 183 294 168 138 30 66 73 47 92 74 89 160 134 87 74 18.42 19.22 17.66 19.12 16.94 18.59 18.72 17.00 17.37 17.03 17.08 17.22 15.91 18.44 15.66 17.93 18.24 17.27 18.07 17.89 16.73 17.08 18.89 19.37 17.75 15.76 18.20 16.29 16.71 16.99 15.90 16.63 18.90 17.75 16.10 18.52 16.92 18.89 19.08 19.04 18.70 18.76 17.31 17.59 18.95 17.80 19.52 18.46 18.41 -0.16 -0.05 -0.04 -0.05 -0.13 -0.80 -0.13 -0.03 -0.13 -0.10 -0.01 1.16 1426727918.55 1.12 0.26 1.14 1.87 0.09 B-v 0.44 0.07 0.16 0.28 1.09 1.58 1.71 1.07 0.03 0.90 0.00 0.15 0.06 0.32 1.27 0.87 0.04 0.95 1.07 1.08 1.53 0.84 0.40 1.24 0.48 0.48 0.16 -0.07 -0.06 -0.09 B-V 0.89 0.81 B-V 13 12 11 10 74 73 72 71 70 59 69 67 58 57 68 66 65 64 56 55 53 63 62 61 54 51 60 52 50 49 48 47 45 42 40 39 38 46 44 43 41 8 9 253 252 250 251 249 N. NGC2172(Center:348,160) M. NGC2164(Center:367,171) N 266 223 265 106 264 174 261 74 262 267 248 23 392 388 397 389 387 388 378 378 377 376 373 374 362 372 370 364 355 350 350 351 349 348 346 344 345 338 337 334 331 348 342 330 328 327 325 322 321 L. NGC2159—Continued 516 518 515 514 513 120 154 209 302 287 271 225 171 134 184 152 305 170 157 229 288 261 245 188 213 133 149 231 171 342 276 204 216 190 157 132 186 313 40 90 29 50 142 117 182 202 84 71 14.88 16.06 14.90 17.90 18.79 18.80 18.48 16.73 15.65 16.56 15.32 16.87 15.79 16.49 18.45 18.22 17.21 16.85 18.87 13.67 16.78 14.61 17.94 16.23 17.69 14.81 16.06 17.79 18.13 15.55 18.64 15.12 17.42 14.03 16.70 15.69 18.14 16.84 17.84 17.79 17.14 18.91 16.41 19.93 20.35 19.61 18.25 19.16 -0.07 -0.07 -0.25 -0.08 -0.27 -0.04 0.26 0.06 0.45 0.08 0.40 0.03 0.06 1.32 0.64 0.05 0.02 1.48 0.84 0.36 1.18 1.21 0.75 0.00 0.00 0.83 2.03 0.60 0.94 1.39 0.16 1.94 1.26 0.96 1.02 0.18 0.01 0.13 0.22 0.13 0.52 0.01 0.71 0.02 B-V B-V 1.21 1.61 1.05 0.14 0.20 B-V 110 108 109 107 106 105 104 103 102 100 101 21 20 19 18 17 16 15 99 98 97 96 95 94 89 88 86 84 93 92 91 90 87 85 83 82 81 80 79 78 77 76 256 255 254 75 N N 289 18 284 165 285 152 283 65 281 180 272 221 273 277 527 510 506 497 497 482 473 467 470 467 459 460 455 453 450 448 441 438 440 432 428 416 420 421 417 416 413 396 396 397 412 407 405 403 401 402 522 524 522 141 212 276 147 175 217 183 143 217 269 219 223 228 183 292 175 261 162 245 196 189 141 179 304 207 190 332 86 39 64 77 88 44 43 75 47 115 19.85 167 18.91 145 19.38 19.33 18.04 19.00 19.48 17.01 17.58 17.97 14.88 18.55 18.74 18.93 18.33 19.08 16.47 18.39 17.85 18.16 17.83 15.84 18.39 18.68 17.77 19.07 16.02 16.62 14.90 15.57 17.78 15.46 18.13 13.59 18.34 16.25 17.12 15.07 14.63 15.77 15.37 18.55 16.99 16.51 16.83 18.69 -0.37 -0.02 -0.15 -0.31 -0.07 -0.07 -0.10 -0.10 -0.02 -0.42 -0.01 0.43 1.51 0.68 0.29 0.35 2.09 0.38 0.76 0.12 0.04 0.08 1.59 1.01 0.22 0.04 1.50 0.27 1.43 1.78 0.03 0.47 B-V 1.48 0.09 0.00 2.01 1.47 0.29 0.45 0.14 0.22 0.21 0.88 1.05 0.66 0.88 B-V B-V 19 91ApJS. . .76. .185E to positionsinFigs.l¿7-lronagridwithoriginthelowerleftcomer (SE),Yrangingfrom0to380,andX10540. omitted.) ±0.05 magforthebrighterstars.UncertaintiesinÆ-Faretypically ±0.10 mag.(Starswithuncertainties\nB-Vgreaterthan±0.5were Magnitudes andcolorshavenotbeencorrectedforreddening.Uncertainties inVaretypically±0.10magforthefainteststarsandlessthan Notes.—Postions, colors,andmagnitudesforstarsderivedfromthe CCD imagespicturedinFigs,\a-\r.TheXandYcoordinatesrefer 19 18 17 16 15 14 13 11 12 10 29 27 26 23 22 46 43 37 36 33 32 31 30 28 25 24 45 44 42 41 39 38 35 40 34 5 3 2 8 4 1 7 9 6 347 343 350 329 337 328 318 316 293 284 271 314 314 311 308 299 271 264 304 298 293 346 340 337 344 339 336 336 327 321 316 314 315 313 310 306 306 305 302 300 328 328 319 317 © American Astronomical Society • Provided by theNASA Astrophysics Data System 208 239 192 251 221 140 193 172 158 258 222 127 217 159 197 144 198 238 278 293 265 163 185 243 122 154 141 174 206 154 217 187 323 107 135 170 111 59 39 86 10 74 84 9 16.76 14.48 16.66 15.90 16.83 16.30 17.25 17.37 18.00 13.29 15.70 17.04 15.63 17.63 17.23 18.33 16.23 16.51 17.77 18.18 17.35 15.81 16.26 13.86 19.30 18.61 19.20 17.28 19.00 17.93 17.22 18.98 16.33 15.53 18.79 19.16 18.63 18.36 15.26 17.10 19.90 18.85 17.57 16.91 V -0.05 -0.07 -0.12 -0.10 -0.16 -0.39 -0.21 -0.86 -0.13 0.05 0.31 0.78 1.54 0.05 1.13 1.06 0.31 1.12 0.87 1.07 1.34 1.08 1.11 0.11 1.10 0.18 0.70 0.07 0.23 0.32 0.06 0.37 0.24 0.91 B-V B-V 20 16 14 21 35 01 42 08 69 60 35 38 37 36 34 33 32 31 29 28 27 24 23 22 30 26 25 21 20 56 53 52 51 59 58 57 55 54 50 71 70 48 47 49 69 68 67 66 62 61 65 64 63 60 O. NGC2214(Center:362,178) 387 383 381 380 377 369 353 351 N. NGC2172—Continued 367 366 366 365 360 356 371 368 360 351 350 389 384 364 357 357 389 385 381 379 376 376 373 371 370 364 359 359 354 353 377 370 345 384 372 350 193 247 223 202 276 205 138 231 152 192 256 176 214 253 260 120 150 133 314 263 215 221 270 224 170 166 199 177 242 160 267 184 119 151 188 187 142 194 139 199 166 144 44 49 203 17.39 17.00 15.02 16.85 17.36 13.80 17.07 15.75 15.70 16.90 16.82 15.78 17.93 14.21 18.04 14.62 15.67 18.31 18.26 17.89 16.66 17.17 14.76 16.12 19.14 18.72 17.75 17.76 18.08 19.48 18.01 19.07 17.81 18.23 17.17 18.29 18.43 16.81 17.45 19.29 14.94 18.21 19.33 16.87 -0.01 -0.12 -0.03 -0.05 -0.07 -0.04 -0.19 -0.44 -0.08 -0.14 -0.39 -0.17 -0.25 -0.14 -0.20 -0.09 -0.26 -0.15 -0.26 -0.29 2.21 0.02 0.49 0.81 0.11 0.61 0.12 0.11 0.24 0.25 0.00 1.48 1.12 0.37 0.12 0.16 0.12 0.68 0.02 0.19 0.15 0.58 0.38 0.00 B-V B-V 55 56 54 53 52 51 50 81 77 72 49 48 47 46 44 43 42 41 39 88 87 86 85 84 83 82 80 79 78 75 74 73 45 40 89 76 95 94 93 92 91 90 390 454 449 394 393 517 414 399 397 395 396 447 446 442 438 412 393 389 490 483 482 480 449 419 410 408 407 406 435 424 414 412 412 405 401 472 457 454 453 447 431 432 272 281 238 220 290 116 161 180 233 158 153 217 242 207 263 258 217 154 192 196 304 127 126 196 151 180 127 181 136 185 164 118 175 177 171 133 53 39 48 84 86 60 16.89 17.09 18.15 19.08 17.52 17.86 16.90 18.80 17.02 14.54 18.01 17.58 18.51 19.03 17.57 18.44 16.74 17.24 19.09 17.90 18.19 18.61 18.70 18.61 15.35 18.23 17.91 17.36 17.99 1-6.78 14.16 18.33 18.43 19.71 19.05 18.25 19.28 18.42 18.29 16.33 15.33 19.69 -0.12 -0.09 -0.11 -0.04 -0.01 -0.12 -0.21 -0.06 -0.09 -0.08 -0.16 -0.12 -0.01 -0.16 -0.14 -0.05 -0.84 1.22 1.27 0.11 0.09 0.14 0.88 0.03 0.36 0.22 0.19 0.62 1.09 0.14 0.61 0.15 0.78 0.33 0.72 0.81 0.38 0.73 0.02 0.09 0.19 0.23 B-V B-V 2002, (Ä)NGC2004,(z)2100, (7)NGC2156,(A:)2157,(/)2159,(w)2164,(«) NGC2172,(ô)2214.Magnitudesandcolors are fromTables3A-30, andareforstarswithin100" oftheclustercenters.Noeffort hasbeenmadetoremovebackground orforegroundstars. > 16 19 91ApJS. . .76. .185E Fig. 3.—(û-o)Color-magnitudediagrams for(a)NGC1711,(¿>)1755,(c)NGC1818,(úf)NGC 1850,(c)NGC1855,(/)NGC1872,(g)NGC Ub- 12 rnij~igi~i -1 -.50 NGC 1818•♦ © American Astronomical Society • Provided by theNASA Astrophysics Data System I 1,-L11. Fig. 3c Fig. 3e .5 11.5 B-V 2.5 204 > 16— 14 — is i rpr'[j|'Tvi~r-¡ ^ NGC1850 Fig. 3c/ Fig. 3/ > 19 91ApJS. . .76. .185E © American Astronomical Society • Provided by theNASA Astrophysics Data System Fig. 3h Fig. 3g Fig. 3/ B-V B-V Fig. 3—Continued 205 > Fig. 31 Fig. 3h Fig. 3j B-V B-V 19 91ApJS. . .76. .185E least-squares proceduretodetermine a,ti,andy.Themodels tidal truncationhashadtime tooccur.Weadoptedthesame which areappropriateforyoung clustersinwhichlittleorno models hereandfittedthem totheobservedprofilesusinga is £^23. the exposuretimewas60minutes,andlimitingmagnitude tralian Telescope,withthetripletcorrector,andGG385filter; EFF adoptedmodelsoftheform photographic plate.TheplatewastakenwiththeAnglo-Aus- aperture photometry,driftscans,andstarcountsfromaIla-O 2209 (seeTable4)derivedbyK.C.Freemanfromconcentric 0 206 ELSONVol.76 In studyingtheouterregionsofyoungLMCclusters, © American Astronomical Society • Provided by theNASA Astrophysics Data System 1211 n(r) =Mo(+rlaY'‘,(2) 2.2.2. ModelsandParameters Fig. 3—Continued Fig. 3o 2 tracted imagesare^15-19magarcsec“inbothVandB. son’s (1974)photographicvalues. ground-subtracted BandVprofilesforeachclusterarelistedin model.) Valuesoffromtheuncleaned,background-sub- to r~250".)Valuesofderivedfromthecleaned,back- Table 1.ThecorrespondingmodelsareshowninFiguresla- ir. (ForNGC2209inFigureIs,themodelshownisaKing contrast, theprofilesusedbyEFFtostudytidaleffectsextend dii, andtheparameteraisrelatedtocoreradiusrof published byKing(1962)reducetoequation(2)atsmallra- clusters (atr<100")wheretidaleffectsarenegligible.(In Note thatthemodelswereonlyfittedininnerregionsof equivalent Kingmodelby c c Fig. 4.—Vmagnitudesforstarsin NGC2214plottedagainstRobert- 2,y1/ r =a(2-1).(3) c 19 91ApJS. . .76. .185E No. 1,1991 indicated. Becker (1981)andBrunish&Truran(1982).Valuesoflog(r/yr)are as longr/FWHM>0.85, correctionswillbesmaller the imagesfromwhichnostarswereremoved.(Again, the radii. Schweizer(1981)examines theeffectofseeingonfitting results forBaresimilar.)Thescatteriswithintheerrors. radii derivedfromcleanedFimagesversusthose King modelstotheprofilesof ellipticalgalaxies.Henotesthat seeing effectsmustbeconsidered indeterminingthetruecore the coreradiisignificantly,wehaveplottedinFigure9 core typically by~40%.Todeterminewhethertheprocessalters profiles considerably,andreducestheerrorsincoreradii, the truecoreradiusforthisclustermaybesomewhatlarger. that thebackgroundforNGC1872wasunderestimated, and traction arealsoshown.ThereissomeindicationinFigure li timated. Fortheseclusters,profileswithnobackground sub- we concludethatuncertaintiesinthebackgroundsdonotaf- suggests thatthebackgroundsweremorethantypicallyoveres- B aresimilar.)Anydifferenceswellwithintheerrors,and these uncertaintiesaffectthederivedcoreradii?Thetrue been overestimatedbynomorethan~50%.Howmuchwill ties werelessthan10%ofthebackgrounddensities.With7= 2156 (Æ),thesteepnessofprofilesinFigures7jand1m fect thecoreradiisignificantly.ForNGC2002(F),and files withandwithoutbackgroundsubtraction.(Theresultsfor subtracted. Figure8showscoreradiideterminedfromVpro- radii mustliesomewherebetweenthosedeterminedfrompro- from profileswhichoverestimatedbackgroundswere files withnobackgroundsubtraction,andthosedetermined as NGC1866.Typically,thebackgroundsweredeterminedat cluster stars,particularlyinthecaseofextendedclusterssuch profiles maybesomewhatuncertainduetocontaminationby discussed further,becausethemoreextensiveprofilesfrom 2.6, equation(2)impliesthatthebackgroundswouldhave EFT givemoreaccuratemeasurementsofthisparameter. Values of7areinthesamerangeasfoundbyEFT;theynot r —200".EFTfoundthatat~240"theclustersurfacedensi- capp Fig. 5.—Isochronesconstructedfromthestellarevolutionmodelsof Since someoftheclustersin oursamplehavesmallcores, Subtracting thebrightstarsfromimagessmooths As mentionedabove,thebackgroundssubtractedfrom © American Astronomical Society • Provided by theNASA Astrophysics Data System RICH STARCLUSTERSINLMC than afactor2-4.(ristheapparentcoreradius.)Forour true coreradii(cols.[8]and[9]ofTable1)aretypically10%- tion 2.25andaGaussianseeingdiskwithFWHM=1"77.The core radii(col.[4]and[5]ofTable1)usingtheGaussian centrations (logrl)of2.25and2.75,bothGaussian cluster tohaveanunresolvedcore.Schweizer’sTableIIgives has r/FWHMcloseto0.85,andwehaveconsideredthis sample, (r/FWHM)=2.8.Onlyonecluster,NGC2002, both fromtheFimages,areindicatedwithtickmarksinFig- and [7]ofTable1),Schweizer’smodelswithconcentra- FWHM oftheseeingdiskmeasuredineachframe(cols.[6] modified Gaussianseeingdisks.Wecorrectedourapparent values oftrueandapparentcoreradiusformodelswithcon- plotted againstthevaluesfromEFF(frommultiaperture additional uncertaintieswillnotaffectourconclusions.The 20% smallerthantheapparentcoreradii.Sincevaluesof except forthetwoclusterswithlargestcores,NGC1831 photometry andstarcountsonphotographicplates),forthe ures la-lr. HWHM oftheseeingdiskandseeing-correctedcoreradii, for ourclusters,thesecorrectionsarenotexact.However,any Schweizer’s parametersarenotnecessarilyidenticaltothose background forthisunusuallyextendedcluster. young LMCclustersremarkedthat“...[they]haveluminos- discrepancy maybelinkedtothedifficultyindetermining value of14"5,and30%largerthanthederivedhere.This core radiusof15"6whichisingoodagreementwithEPF’s agreement withourvalueof14"2.ForNGC1866,hefindsa and NGC1866.For1831,M.Mateo(1989,privatecom- munication) findsacoreradiusof14"8,whichisinexcellent 3. THEFORMATIONANDEARLYEVOLUTIONOFLMCCLUSTERS capp tc capp capp 10 clusterscommontobothsamples.Theagreementisgood, and havea=1"!72.4. a backgroundfromtheprofile.The solidcurvesarethebestfittothisdata and nobrightstarsremoved.The dottedcurveisthebestfittothisdata The squaresarederivedfromtheV imagewithnobackgroundsubtracted same imageafterremovingthebright starsfromtheframeandsubtracting from eq.(2)andhasa=6''47 =2.0.Thecirclesarederivedfromthe Figure 10showsthefinalcoreradiifromFCCDimages Over adecadeago,twostudiesofthestructureseveral Fig. 6.—Surfacebrightnessprofiles foratypicalcluster,NGC1711. 207 19 91ApJS. . .76. .185E and tidalradiiconcentration parameter careindicated. derived fromaperturephotometry (opencircles),driftscans(closedcircles),andstarcounts(asterisks). AKingmodelwasfittedtothedata,andcore background subtractedarealsoshown. ForNGC2157aprofilederivedfromtheimagewithnobright starsremovedisincluded,(s)ProfileforNGC2209 the seeingdisk,andbest-fitting valueofr.Whereonlyonetickmarkappears,itisbecausetheHWHM ^1.0.(û)NGC1711,(6)1755,(c) described inthetext.Backgrounds havebeensubtracted.Solidanddottedcurvesarethebest-fittingmodels fromeq.(2).TickmarksindicatetheHWHMof 2156, (n)NGC2157,(o)2159, (p)NGC2164,(q)2172,(r)2214.For2002and NGC2156,dataforBandK,respectivelywithno 1818, (i/)NGC1831,(tf)NGC1850, (/)NGC1855,(#)NGC1866,(6)1868,(/)NGC1872,0) 2002,(Â:)NGC2004,(/)2100,(/n) c Fig. 7.—(as).Surfacebrightnessprofilesfortheclustersinoursample derivedfromV(circles)andB(squares)images,withthebrightstarsremovedas © American Astronomical Society • Provided by theNASA Astrophysics Data System 208 Fig. If c l°g(r/arcse) 19 91ApJS. . .76. .185E © American Astronomical Society • Provided by theNASA Astrophysics Data System Fig. lg Fig. Ik l°g(r/arcsec) Fig. 7—Continued 209 Fig. Ij r Fig. Ih Fig. 11 logír/arcsec) l°g(/arcsec) logCr/aresec) 19 91ApJS. . .76. .185E © American Astronomical Society • Provided by theNASA Astrophysics Data System Fig. 7—Continued 19 91ApJS. . .76. .185E 7 to notethatNGC3603,amassive openclusterintheMilky Way, withagesimilartothat of30Doradus,alsohasavery pc, whiletheoldestclustershave r^0-6pc.(Itisinteresting distance totheLMCof52kpc.)Thereappearsbeanupper and earlyevolutionoftherichLMCclusters. the profilesinFiguresla-lscantellusaboutformation limit increaseswithage.The youngestclustershaver^0-1 pation, butnotbytwo-bodyencounters.Wenowexplorewhat initial conditions,modifiedbyviolentrelaxationand/ordissi- ation times(EFF),theirpresentstructureshouldreflect because theseclustersarenotoldenoughtohaverelaxedinthe limit totheradiusofcoresclusters,andthisupper Table 1,andfor17additionalclusterswithpublished core Here, coreradiusisshownplottedagainstagefortheclusters in clusters areyoungerthaneventheircentraltwo-bodyrelax- under closerscrutiny.Furthermore,sincethe~10yr-old LMC clustersarereallyrepresentedbyrelaxedKingmodels radii, listedinTable4.(Thevaluesofrfromcol.[8] Elson, Freeman,&Lauer(1989),isillustratedinFigure 11. usual way,”(Freeman1974).WiththeprofilesinFiguresla- ity profilesthatarewellrepresentedbyKing’s(1966)relaxed ls,we maynowjudgehowwelltheinnerregionsofyoung models ...”(Chun1978),andthat‘Thisresultisinteresting, c 1 havebeenconvertedfromarcsecondstoparsecsassuming a c c A strikingresultofthepresentstudy,alreadydiscussedby © American Astronomical Society • Provided by theNASA Astrophysics Data System 3.1. CoreExpansion - 1-00.80-6-0-40*200-20-4 RICH STARCLUSTERSINLMC Fig. 7—Continued Fig. Is log r(arcmin) -1 7 -(1+x) 1 9 x: <2.5.Thisrangeisbracketed bythatfoundintworecent power-law IMFsareshown.(TheIMFisgivenby oc the centerofLMC(themeandistanceclusters in curves arefromFokker-PlanckmodelskindlyprovidedbyM. pansion ataconstantvelocityof0.02kms.(Thisissmall stellar evolution.ThedottedcurveinFigure11illustratesex- small corewithr=0.024pc;Moffat,Seggewiss,&Shara parameters areneededtointerpret thisscatter.Itmayimply considerable scatterinx,and modelswithawiderrangeof after ~4X10yr,whilethecoresofmodelclusters with Table 1).Modelscalculatedforclusterswiththreedifferent of themassesdeterminedbyEFF),atadistance3kpcfrom Chemoif &Weinberg’smodels),M=6X\0*M(typical evolution ofaclusterwithW=1(themostconcentrated Weinberg (seeChemoif&1990).Theyillustratethe cluster-to-cluster variationsin IMFslopeintherange0.5< suggests first,thattheclustersstartoutmoreconcentrated than slightly ornotatall.Comparingourdatawiththesemodels steep IMFs(proportionallymorelow-massstars)expand only masses is0.4-14M).Themodelclusterswithx;=0.5disrupt compared tothecentralvelocitydispersionswithinclusters m, wherejc=0.5,1.5,and2.5,therangeofstellar of ~1-2kms";seeEFFandLuptonetal.1989.)Thesolid ~ 10yristhatthesecoresareexpandingduetomasslossfrom sample hasx:^1.0.However, thedataareconsistentwitha 1985.) c Wq =1,andsecond,thatatypicalIMFfortheclustersin our iráxiíAo Q o A possibleexplanationfortheincreaseincoreradiusupto 211 ELSON Vol. 76

Fig. 8.—Core radii determined from profiles from cleaned V images Fig. 10.—Core radii of cleaned, background-subtracted V profiles, before and after background subtraction. Results are similar in B. corrected for seeing, plotted against published values for 10 of the clusters in Table 1. studies of IMFs in Magellanic Cloud clusters: Elson, Fall, & Freeman ( 1989), derived -0.2 < x < 0.8 for six of the clusters with the data presented here, their effect on precore-collapse in the present sample, while Mateo (1988) derived 1.5 < x: < evolution is probably small. The clusters cannot avoid losing 3.5 for a different sample of five EMC clusters and one SMC mass through stellar evolution, and the models in Figure 11 cluster. suggest that this mass loss is sufficient to account for the ob- Mechanisms other than stellar evolution that could produce served expansion, if the IMF is allowed to vary within the expansion in a cluster core, for example the formation of bi- range estimated by Elson, Fall, & Freeman and by Mateo. nary stars or a central blackhole, are often discussed in the Could the trend in Figure 11 be produced by selection effects context of post-core-collapse evolution. While the relevance or by a conspiracy of other correlations? If there were young of these mechanisms for young clusters cannot be ruled out clusters with large cores and systematically lower surface bright- ness, then these clusters might have been omitted from our sample, which was selected to include the brightest clusters in

Fig. 11.—Core radius vs. age for the clusters in Table 1 ( circles; rc from col. 5 ), and Table 4 ( triangles). Solid curves are from Fokker-Planck mod- Fig. 9.—Core radii determined before and after removing the bright els of clusters with power-law IMFs with the slopes indicated. (The Sal- stars from the image. Values are from background-subtracted profiles from peter IMF has je = 1.35). The dotted curve corresponds to expansion at a V images. Results are similar in B. constant velocity of 0.02 km s-1.

© American Astronomical Society • Provided by the NASA Astrophysics Data System 19 91ApJS. . .76. .185E 7 7 No. 1,1991 Galactic globularstabulatedbyWebbink(1985).(Ofthe between massandageforthe10clustersstudiedbyEFF. there isneitheracorrelationbetweencoreradiusandmassnor 7V-body systems.Suchsystems willundergoviolentrelaxation core radiusandclustermass,massage(e.g.,if tween centralsurfacebrightnessandcoreradiusforthedozen from —0to-7pc.Thisisthesamerangeas90%of~150 more massiveclusterswithlargercoresformedinthepast): upper envelopeisunlikelytobeduecorrelationsbetween clusters inFigure11withlog(r/yr)~7.5.Furthermore,the the LMC.However,thereisnoevidenceofacorrelationbe- (EFF). Itisthereforeplausible toconsidertheseclustersas for formingstarsandshedding unusedgasis10yrorless clusters inoursamplearetypically ~10yr,andthetimescale lapse willbeessentiallydissipationless. Crossingtimesforthe compared tothecrossingtime,andwithhighefficiency, col- than thoseatsmallergalactocentricdistances(ChernofF & large galactocentricdistancesareexpectedtocollapselater ing andarebeginningtocollapse(seeMateo1987).Clusters at for theclustersinTable4. Djorgovski 1989),and,asnotedbyMateo,thisisindeed true indicate thatthecoresofsomethesehavestoppedexpand- The scatterincoreradiusoftheoldclustersFigure11 may —130 Galacticglobularswithr<7pc,halfhave1pc.) c 9 The clustersolderthan^10yrhavecoreradiiranging If starformationwithinaprotoclusterproceedsrapidly 3.2. InitialSize,Temperature,andClumpiness b a C enees. ter age,fromElson&Fall(1988);bracketedval- NGC 2005(9.8)<0.5 NGC 1786(9.9)0.8 ues arefromMateo(1987)orthefollowingrefer- Feitzinger (1983).Col.(3):coreradiusinpc.Val- ues arederivedfrom5valuesElson&Fall H14 9.22.5 Hl 110.14.8 NGC 225710.16.7 NGC 22109.91.8 NGC 22099.05.0 NGC 21559.33.8 NGC 19789.43.0 NGC 1852(9.7)4.0 NGC 18477.41.3 NGC 1835(9.9)0.9 NGC 1754(9.8)1.2 NGC 17189.32.8 NGC 1466(9.9)3.9 NGC 2019(9.8)<0.5 30 Dor6.50.2 1988. Lastentryincol.(2)fromBraunswurth& 1985 withtheagecalibrationfromElson&Fall c b a © American Astronomical Society • Provided by theNASA Astrophysics Data System Moffat,Seggewiss,&Shara1985. K.Freeman(unpublished). Nelson&Hodge1983. Notes.—Col. (1):clustername.Col.(2):clus- Name log(r/yr)rj^c (1) (2)<3) Published CoreRadii TABLE 4 RICH STARCLUSTERSINLMC 7 7 A-body simulationsofmergers.Multiplecoevalclusters are Figure Ir.Anotherexample isNGC1850,wherethepro- Figure Is,showsupasaslight bumpatlog(r/arcsec)æ1.4in process ofmerging.Thesecondaryclump,whichisvisible in and havesuggestedthatthismaybeabinaryclusterin the the contextofellipticalgalaxies(seeLarson1974;Binney body ofthecluster. noted thepresenceoftwoconcentrationsstarsinNGC2214 pear asclumpswithinclusters:Bhatia&MacGillivray(1988) single molecularclouds.Smallersubcondensationscould ap- is plausibletoconsidertheseaslargesubcondensationswithin common intheLMC(Bhatia&Hatzidimitriou1988),and it vate communication)findsthatsharpshouldersappearin his effect ofdissipationoncoreformationhasbeendiscussed in duce theobservedsharpshoulders.Itispossiblethatsmall principally fromtheclumpin Figure1eduewestofthemain nounced bumpinFigurele atlog(r/arcsec)^1.5comes cores mightariseifdissipationplayedasignificantrole;the ence isexacerbatedforthewarminitialconditionswhichpro- imply muchlargerinitialsizethanMcGlynn’s,andthisdiffer- For coolorwarmconditions,vanAlbada’smodelsseemto bada’s resultsintermsoftheinitialsizeprotoclusters. end oftherange0.1-0.25estimatedbyEFF. dimensions oftheprotoclustersconsiderablylargerthan the maximumradiiweretypically10R,whichimpliesinitial suggest acorrespondinglysmallvalueofTIW,atthe“cool” from moreextendedsystems,thenthesmallcoresat—10yr values inferredfromMcGlynn’swork.Iftheclustersdidform for 10oftheclustersinpresentsample.Fortheseclusters, models andinferredinitialhalf-massradii,of~10-30pc the coreistoosharptoberepresentedbyequation(2),much tions (Tq/Wq^0.25)resultinprofileswheretheturnoverat Interestingly, McGlynn’smodelswith“warm”initialcondi- The expansionfactorsestimatedfromtheunboundhalosare initial limitsandmayhavesubstantialhalosofunboundstars. plies, asEFFargued,thattheclustershavespilledbeyondtheir 0.05