© Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México itn lse oe1 p rmteSnand the ( from Center Galactic kpc the from 19 kpc some 21 cluster distant δ 03) t lsicto sa otro yeI type Oosterhoff an 2003a, as classification al. Its et the (Bellazzini of 2003b). that member cluster the suggested dSph a in been been Sagittarius have immersed has may clusters it it globular originally and the Stream of Sagitarius one is It eit eiaad srnmı Astrof´ısica Astronom´ıa y de Mexicana Revista u´ nm eM´exico, M´exico.Aut´onoma de +18 = 1 3 2 h lblrcutrNC44 safitand faint a is 4147 NGC cluster globular The AIBESASI G 17RVSTD RLRESASNEW LYRAE RR REVISITED: 4147 NGC IN STARS VARIABLE nttt eAtoo´a nvria Nacional Universidad Astronom´ıa, de Instituto ninIsiueo srpyis aglr,India. Bangalore, Astrophysics, of Colombia. Institute Antioquia, Indian de F´ısica, Universidad de Instituto ◦ 32 ′ 31 CCD atnecad o ´mlstp oI end o u estrel sus por definida Words: I, Key Oo c´umulos tipo los de tendencia la eOsehff aetutr es aahrzna umetali su y horizontal rama plano su el extragal´actico. En de origen co estructura su interpretaci´on clasificarse c´umulo de La puede El comparten Oosterhoff. RRc inestabilidad. de c´um y de al RRab zona distancia SR estrellas la la las tipo en estimar que del observa para variable Se empleada una ser pendiente. como pudo ahora y 24.8d confirma de se duda, en puesta 19 eispr amtlcddydsacaa ´ml e[Fe/H] estrell c´umulo de al Las distancia y establecidos. metalicidad curva la bien sus para cero de medios Fourier puntos descomposici´on de y la calibraciones de medio por laron aeago aefretaaatcoii.I olw h dis the follows It origin. the in extragalactic st clusters for branch globular case horizontal cl good Its The a type. get make branch. Oosterhoff to horizontal intermediate RRa used the of the been in that as has region observed b it inter-mode is and It to the 24.8d, share cluster. confirmed about the of is of estimate period dispute, distance a in with type previously SR been has variability ons h enmtliiyaddsac siae sn t using estimated distance decomposition and Fourier mean the semi-empirica [Fe/H] well-established The via and 4147 data points. new NGC using cluster curves, globular the . 8 .INTRODUCTION 1. .Aeln Ferro Arellano A. . ′′ 05 J2000; , ± o a´mto ´scsd a srla RLree G 414 NGC en Lyrae RR estrellas las de f´ısicos par´ametros Los ehv acltdtepyia aaeeso h RLrest Lyrae RR the of parameters physical the calculated have We ZW VI 0 . 6kc epciaet.L srlaV8 uavariabilida cuya V18, estrella La respectivamente. kpc, 46 = l HTMTYADPYIA PARAMETERS PHYSICAL AND PHOTOMETRY lblrcutr:idvda:NC44 tr:variables stars: — 4147 NGC individual: clusters: globular − 252 = 1 . 72 eevdJnay3 08 cetdArl92018 9 April accepted 2018; 30 January Received ± . 1 84 .C oa Galindo Rojas C. F. , α 0 ◦ . , 5ad19 and 15 12 = M b V +77 = − h F/]pae sdpce rmteRcstars. RRc the from depicted as plane, [Fe/H] 10 m , . . 18 06 05 54 ABSTRACT RESUMEN ◦ . 2–3 (2018) 325–339 , ± ). s , 0 . 6kc epciey h trV8 whose V18, The respectively. kpc, 46 2 .Muneer S. , itiuino h R tr,tigrtepossibility the trigger stars, RRc the amplitude-period and of structure considera- among distribution HB However, the cluster as clusters. such globular tions I poor type Oosterhoff prob- metal is the most It the plane. dis- ably amplitude-period Lyrae Smith the RR & in the Catelan tribution from Stetson, SCS05) the by 2004 (hereinafter of and (2005) periods stars, al. revised Lyrae et the RR Ferro classifica- from Arellano This AF04) by (hereinafter confirmed population. was Lyrae tion stars RR type RRc the horizontal of fraction among blue large controver- abundance, the and was metal (HB) branch low 1987) its Quarta given & sial (Castellani I) (Oo M 3 n uer Giridhar Sunetra and , V − sRcidcnvalores indican RRc as ZW n R tr onot do stars RRc and b utr n metallicity and ructure airtosadzero and calibrations l odltp intermedio tipo del mo F/]e c´umulo sigue el [Fe/H] rbto fO type I Oo of tribution se a eclassified be can uster a ioRRc. tipo las elz empleando luz, de s l emnr inde- manera de ulo aibeo the of variable a e = azn inter-modo zona la ia aoee la favorecen cidad eRcsasare stars RRc he − nindependent an 1 o nperiodo un con . fterlight their of 72 hab´ıa sido d RLyrae RR : ecalcu- se 7 ± 0 . 5and 15 r in ars 3 325 © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México ag aaee morphology a of parameter display their large the of consequently and peculiar, modulations (AF04) curves amplitude is light observed RRab the the known curves to five both light due the the In all that 2018). in clear SCS05. RRc morphology became al. by it and et studies, performed RRab Yepez above also I both (e.g. was types of II) stars Oosterhoff decomposition Oo both and Fourier I of A (Oo clusters II of and (CMD) family diagram dis- a have magnitude Lyrae and to colour RR the 2017), the on of 2013; tribution analysis homogeneous critical al. very the a et expanded in Ferro stars proper- (Arellano RRc physical way and estimate RRab of to ties calibrations zero-points semi-empirical their the AL. of ET and usage sys- FERRO standard the ARELLANO the on to tem, transformations (Bramich and reductions 2013) data al. cluster. et the the to several related upon to improved procedures have distance we then, and since However, estimate metallicity to mean decomposed Fourier the were Lyrae RR the the in dis- paper. be this shall in as type later origin, cussed intermediate extragalactic Oosterhoff of of and (Oo-Int) is clusters the that 326 prahadterifrneo the decomposition on Fourier inference the Arellano their from by and (2017) presented approach clusters al. 24 of et some Ferro scales homogeneous of and the family in metallicity a cluster the the set to with to distance comparison and proper discussions a ob- col- previous for data was the time-base cluster enriching and of the aim lection the reasons, with above 2012 or- in the served in all is obtained For decomposition as curve der. quantities light Fourier physical reconsider- the stellar a from Thus, the of effect. ation Blazhko the frequen- and/or secondary of cies presence the with may connected as that be such modulations amplitude papers, V16, and above phasing V13, the erratic (V11, in variables encountered were period V17) long anomalies rather numerous the the stars, for in RRc metallicity the higher Among much cluster. a AF04 found both why SCS05 reason and the probably cal- is metallicity This for unsuitable ibration. as curve light the veals ercsse in the system as photo- metric well Johnson-Kron-Cousins the as to reductions transformation data and observations our lation. h nw aibe n siaetecutrredden- in cluster the ing estimate and variables known the h ore eopsto o RLresasin stars Lyrae RR for decomposition Fourier the edsustepclaiiso oeidvda stars individual some of peculiarities the discuss we h lse aibesaswr tde yAF04 by studied were stars variable cluster The h ae sognsda olw;w describe we follows; as organised is paper The § V ;w aclt h hsclprmtr via parameters physical the calculate we 3; and R adpse n h ih uvsof curves light the and passes band § ;w efr h dnicto of identification the perform we 2; D m SS5,wihre- which (SCS05), M V − F/]re- [Fe/H] § 4; aacnitdo 153 of consisted data h lse.W sdthe of field used the We in sources cluster. point the all of time- photometry high-precision difference series extract the to used (DIA) We analysis image procedures. correction field the and conditions. observations seeing our of summary overall an gives .9 rsc i,tasaigit edo view of field 10.1 a approximately into of translating (FoV) pix, arcsec/ 0.296 bv e ee nteHmly.Tedtco a a was 2048 m detector of The 4500 CCD Himalaya. at SITe002 the in located level sea India, Ob- above Hanle, Astronomical (IAO), Indian the servatory with at 2012 2.0m-telescope April 29 the and February 5 between obtained Cousins * the in column last the listed. In is seeing times. average exposure the of range the provide nafml fgoua lsesin clusters globular of family a in ihthe with scrn n eoaehrzna rnh(ZAHB) branch horizontal in age fitting zero and isochrone osbeetaaatcoii r h oistreated topics the its are hence in and origin gap extragalactic Oosterhoff possible the in position cluster in methods several vial at available umrs u eut in results our summarise Columns 020-91 2-0 010202.2 2.7 2.5 2.2 100-200 100-150 10 2.4 110-150 2 3.0 220-300 7 1.7 60-150 15 300-350 250-300 85-120 11 19 2.5 2012-04-29 7 90-250 35 2012-04-28 150-300 50-120 18 11 2012-04-11 240-350 19 30-150 35 2012-03-02 300-450 250 12 18 2012-03-01 170 20 2012-02-29 140-350 35 2012-02-28 2012-02-05 § 4 § oa:13121 153 Total: mg aawr airtduigba n flat- and bias using calibrated were data Image h C bevtosi h Johnson-Kron- the in observations CCD The Date DanDIA ITIUINO BEVTOSOF OBSERVATIONS OF DISTRIBUTION M ;w omn ntedsac otecutrvia cluster the to distance the on comment we 5; .OSRAIN N REDUCTIONS AND OBSERVATIONS 2. ;w rsn G 17i h esetv of perspective the in 4147 NGC present we 8; V [eH eaindtrie rmRcstars RRc from determined relation -[Fe/H] V VI § N sbitfo h aILlbayo D routines IDL of library DanIDL the from built is http://www.danidl.co.uk 2.2 and ;teOsehfftp fNC44,the 4147, NGC of type Oosterhoff the 7; V bnsue ntepeetwr,were work, present the in used -bands N V ieec mg Analysis Image Difference . and I lesrsetvl.Columns respectively. filters 2.1 t N V § I G 4147. NGC Observations . (s) AL 1 TABLE ;w ics h M n the and CMD the discuss we 6; ietenme fiae taken images of number the give V × 08pxl ihasaeof scale a with pixels 2048 n 121 and § N DanDIA I 10. × * t 01arcmin 10.1 I s v eig(”) seeing Avg (s) I § 4 ;adfial we finally and 9; mgs al 1 Table images. ieiefrthe for pipeline t 2 V Our . and t I © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México ffe u oti ro a fteodrof magnitude order the The of was error this image. to each due fac- offset scale to photometric the corresponding the of tor value by fitted photometry offset the the magnitude in into error the introduced be for may solve that to (2012) Freudling the details. relevant which the to for (2011), referred al. is et available reader Bramich is interested by procedure paper 2008). the the the (Bramich in of of array description images pixel detailed discrete of A a pair as a field of convolution same PSF the the models matching that kernel which algorithm 2013), al. an et includes (Bramich process reduction data online. viewed be images can our figure of color FoV The the 4147. in NGC (2000) of Stetson of set standards a in- using of the systems between photometric standard relationship and transformation strumental The 1. Fig. community/STETSON/standards edo G 17 eietfid37sasi h FoV the V-I in with stars images, 337 our identified of we 4147, NGC of field spbihdi al hc sa xrc rmthe from extract an is which 2 Table in published is The 1. Figure of resulting panel as corresponding the equations colour, in transformation given the The are on 1. Figure dependence in mild displayed a show dif- magnitude ferences instrumental 1992). the minus (Landolt standard The Johnson- system the photometric to Kron-Cousins system instrumental our transform 2.3 5 rmtesadr tr fSesn(2000) Stetson of stars standard the From eue h ehdlg fBaih& Bramich of methodology the used We http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/ ihn0 within rnfraint h ISadr System Standard VI the to Transformation . VI . htmtyfralvralsi u FoV our in variables all for photometry 0–2 . 7mg hs tr eeue to used were stars These mag. 37 V nterne1.–15mgand mag 14.6–21.5 range the in ≈ G 17REVISITED 4147 NGC mmag. 5 5 nthe in 16)ta Rbsashv erytesm in- same the nearly ( have colour stars trinsic RRab that (1966) peripheral cluster the for 3 regions. Figure core of and RR charts the the of in 2. curves Figure light in The shown are stars SCS05. Lyrae adopted of have we period curves photometry light the our with stars by For covered our 9. poorly are from Column periods in found the listed ones it data, cases the and some from SCS05, in different by significantly that listed noted as include be we periods should the comparison, (CVSGC) For 7 Clusters Column 2001). in Globular al. Catalogue in in et the (Clement listed Stars from taken Variable coordinates were of The 11 am- and magnitudes, 10 mean Columns periods. their and with plitudes, along 3 Table in pnigdt rm20 A0)cnb on nthe in found be can corre- CDS (AF04) The 2003 from format. data electronic sponding in available table, full au ( value RMxAA/40.209 aibeFle HJD Filter Variable 02TIME-SERIES 2012 trI d (mag) (d) ID Star 6 ti elkonfo h oko Sturch of work the from known well is It identified are 4147 NGC in variables known All listed are FoV our in stars variable confirmed All http://cdsarc.u-strasbg.fr/viz-bin/Cat?J/other/ e site. web V1 V1 V1 V1 V2 V2 V2 V2 ...... OFRE G 17VARIABLES 4147 NGC CONFIRMED V .VRAL TR NNC4147 NGC IN STARS VARIABLE 3. − I ) 6 0; min B V V V V I I I I ...... − 3.1 0 = AL 2 TABLE V Reddening . . ) VI 58 0 456.47 17.339 17.325 2455963.24476 2455963.23776 456.37 16.616 16.708 2455963.23776 2455963.23072 16.512 2455963.22529 456.25 16.542 2455963.22752 456.22 16.187 2455963.22529 456.25 16.197 2455963.22752 tmnmmlgt The light. minimum at ± HTMTYFOR PHOTOMETRY 0 . 2wsclbae by calibrated was 02 ...... M ...... std 327 © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México nNC44 rmtermnmmvlein value stars minimum RRab their four from re- of 4147 these reddening NGC used in the have calculate We to (2005). sults al. from et data Guldenschuh to with black phased and 4147 2003 NGC from in stars data Lyrae to RR correspond the symbols of red curves Light 2. Fig. AL. ET FERRO ARELLANO 328 on naverage an found naverage an E(V-I)/E(B-V) clfl ikenr(01 .2.W hl adopt shall of We maps 0.022. reddening E(B-V) (2011) the Harris Finkbeiner by by & given listed Schlafly value 0.02, the value or the (1996) than smaller little a ntenmnltr ermn h edrta the that reader clearness the of remind sake we the nomenclature for the reproduce however, & in not here; Bramich do details Ferro, we the briefness be Arellano For can by (2017). clusters, paper Giridhar globular the previ- of our in family of found a points several for in zero papers way their ous homogeneous and a in calibrations used method specific the of the well- description ad-hoc and full of A of employment calibrations. the decomposition tested and Fourier curve the light via the estimated be can .PYIA AAEESO RLYRAE RR OF PARAMETERS PHYSICAL 4. hsclqatte fidvda RLrestars Lyrae RR individual of quantities Physical .1i h eane ftepaper. the of remainder the in 0.01 = E(B-V) .5 Shee ta.19)w get we 1998) al. et (Schlegel 1.259 = E ( 0 = V − STARS . 008 I 0 = ) ± 0 . 010 . 0.Ti au is value This 002. ± 0 . 0.Taking 003. V-I and prosrslscnb bandi ih uvswith curves and light curve if light obtained be the can of results morphology spurious the to sensitive al. et Ferro Arellano in (2013). detail in points discussed zero been their have and calibrations These (1998). rcsik o´ c 19)frRcsas h ffcietemper- effective The ature stars. and RRc (2007) Wieckhorts for stars, iron Kov´acs & (1998) Wahl RRab Morgan, the of of those for magnitude and absolute (2001) Kov´acs and Walker & abundance & Kov´acs Jurcsik by and developed (1996) calibrations the of where otn sue odrv h etfi auso the of values fit best the derive to amplitudes used is routine and riod, oet.Fo h mltdsadpae fthe defined of parameters, Fourier phases the as and 1, Eq. amplitudes in the harmonics From ponents. ih uv a erpeetdb h equation, the by represented be can curve light m φ ( h aclto ftepyia uniisi very is quantities physical the of calculation The ehv rudi rvosppr nfavour in papers previous in argued have We 02 h oo gr a evee online. viewed be can figure color The 2012. t ij = ) h eid itdi al .I h pe panels, upper the In 3. Table in listed periods the T = m eff ( A jφ t stemgiuea time at magnitude the is ) 0 setmtduigteclbaino Ju- of calibration the using estimated is E i A + − k steeoh ierminimization linear A epoch. the is k X iφ N n phases and =1 j and , A k cos R ij  φ 2 = P k π A ftesnsia com- sinusoidal the of k i /A ( t − j r computed. are , E t , + ) P stepe- the is φ k  , (1) © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México * a epnigpyia aaeesfrtems sta- most cor- the The for ampli- parameters in curve. When care physical amplitude taken responding 4. maximum have Table the we in present, fitting given and are variations RRab are tude 5 stars the RRc for 9 parameters fitting light-curve 19)adKvas&Knu 19)hv defined Kov´acs have parameter” & (1998) “compatibility Jurcsik Kanbur a stars, Kov´acs & calcu- RRab and the in (1996) for [Fe/H] particular, of In lation in- curves. of light cases or complete with modulations, those phase example and/or amplitude for considered, are peculiarities rto.I h rsn aew oeta l five all and that variations, note amplitude we show their case stars present RRab cali- the known abundance In establish iron analysis to Kov´acs (1996) bration. under used & curve calibrators Jurcsik light the the with the consistent if is 3.0 than smaller eeas o nlddi h hsclprmtrcal- V16) parameter physical and the culations. V13 in included (V8, peculiar not phasing some also were erratic Likewise, with stars ignored. RRc were 2001). Walker they (Kov´acs & the Thus, harmonics of third amplitudes and ab- the cal- the first on [Fe/H] since depends estimation, for magnitude distance fit solute a neither for are nor they culation hence 4), Table EEA AAFRALCNIMDVRALSI G 17I H Fo THE IN 4147 NGC IN VARIABLES CONFIRMED ALL FOR DATA GENERAL aibeVariable Variable eidetmtsfo C0 r itdi oun7frcompar for 7 Column in listed are SCS05 from estimates Period trI ye(a)(a)(a)(a)()(24000 ti ok ( work) (this 000) 450 (+2 (d) (mag) (mag) (mag) (mag) Type ID Star au ae rmSCS05. from taken Value 1 R 17.03 RRc V19 1 R 6981.1 .5 .8 .72958.050.3748 0.3721 5988.3095 0.3563 5963.4587 0.371229 0.4083 5963.4586 0.285 0.372259 0.453 5963.3660 0.257 0.504 0.356376 13.929 0.3874 16.512 0.388 0.233 0.408320 5986.5132 0.3523 16.211 0.432 5963.3836 16.968 0.282 SR 0.504700 16.483 0.385 5963.2378 16.707 0.387419 RRc 0.882 16.322 16.914 0.269 0.352301 1.164 V18 RRc 0.380 16.701 0.302 16.858 V17 RRc 16.471 0.421 V16 17.199 RRc 16.585 16.867 V14 RRab 17.020 V13 RRc V12 RRc V11 V10 2 R1.813.87 14.98 SR V20 8Rc1.2 6580410390285 9348 0.27859 5963.4587 0.5143 0.278652 5986.4396 0.30006 0.60 0.309 0.514245 0.431 5963.2723 0.2805 5963.3748 0.823 16.558 0.300031 1.301 5986.5186 0.609730 0.493 16.828 0.389 0.2805427 16.567 0.810 0.500 5988.3470 0.482 1.208 0.333 5988.49483 17.066 RRc 16.750 0.485 16.455 0.493180 0.500403 RRab 16.710 17.047 16.941 0.65 V8 0.70 Bl 17.031 1.161 RRab RRc V7 16.600 1.05 RRc V6 16.535 17.089 V4 Bl 17.066 RRab V3 Bl RRab V2 V1 eetees h au of value the Nevertheless, D m ausaealvr ag Clm 0in 10 (Column large very all are values h V h i a a 12.391 16.72 D A I m i 0 a hc hudbe should which a n h Fourier the and > . 481:00.3+18:32:11.6 12:10:05.63 24.8 – – – 0.2 0.28 A 0.06 V a G 17REVISITED 4147 NGC 0.14 > A . 20:32 +18:49:14.2 12:07:33.22 – – – 0.1 I a AL 3 TABLE P .793––1:02.8+18:35:02.1 12:10:21.98 – – 0.273933 SS5 HJD (SCS05) h itnecluain eadopted we calculation, distance the siae in estimated ewe hs w clsi fteform: the transformation of The the is in scales (2009). two and these al. (1984) between West et & Carretta Zinn of of is scale scale abundance val- the by iron weighted in mean The are given The table uncertainties. the statistical of 5. the bottom the Table in given in ues summarized are stars iey h assadrdigvni al are 5 Table in given units. radii solar and in expressed masses The tively. es- be can log radius equations: and the mass from for its timated star, temperature Lyrae and RR luminosity, each period, the Given acai(90.W adopted We (1990). Cacciari 1 laa&Bkr17) and 1971), Baker & Albada erccreto a acltduigteformula the using calculated BC was correction metric l R tr r itdi al .Teabsolute The 5. Table in listed are magnitude stars RRc ble log( . 7log 47 snwt u eid itdi oun9. Column in listed periods our with ison h eutn hsclprmtr fteRRc the of parameters physical resulting The lolse r h orsodn distances. corresponding the are listed Also L/ [Fe 0 = L / ⊙ H] . P = ) 6[Fe 06 VES UV F max M 1 + § V − 3.1. / 0 . a ovre nolmnst with luminosity into converted was H] 4lg( log 24 . ( 4 = ZW M (d) P 771:00.1+18:33:00.0 12:10:08.51 9737 V − − 0 + 0 21:67 +18:32:28.4 12:10:06.70 700 +18:32:04.5 12:10:04.96 +18:31:48.4 297 12:09:59.38 393 0 0 11:00.6+18:32:39.7 12:10:06.66 21 31:01.7+18:34:51.2 12:10:10.67 +18:32:40.1 43 12:10:07.35 +18:32:32.4 34 12:10:06.94 +18:32:14.1 75 12:10:06.37 19 +18:31:51.8 12:10:05.53 +18:31:48.4 23 12:10:03.74 39 31:00.8+18:31:58.5 12:10:04.38 43 L/L − . . 21:69 +18:32:34.8 12:10:06.95 9 +18:32:50.2 12:10:06.39 6 5 [Fe 356 1 0 + 413 . M 6gvnb adg & Sandage by given 06 FORIMAGES. OUR OF V ⊙ bol ⊙ M ) 20.)(J2000.0) J2000.0) L − bol ⊙ ADec RA =4 + / M/M . H] 5 3 [Fe 130 BC . 4 = πR 2log 12 ZW 2 E(B-V) 2 ⊙ .Tebolo- The ). . 5mg For mag. 75 σT . 16 = / H] 4 T ZW eff respec- =0.01, . 907 (van 329 (2) − * © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México u.I al els h ie fmxmmand maximum of times maxi- the magnitudes of list corresponding times we their 6 more Table three In present identified the mum. In have 67.9d. we about data of period Blazhko likely 3 RLAOFROE AL. ET FERRO ARELLANO 330 mltd ouain.Aayigtemagnitude light the maximum Analysing at modulations. amplitude stars. anomalous specific of peculiarities tain * ter * h ubr nprnhssidct h netit ntel the in uncertainty the indicate parentheses in numbers The egtdmean Weighted 1 6982 .9 3 .1 3 .0 3 .0 3 .2 (3 4.728 (3) (1 0.006 5.134 (3) (1) 0.006 (1 0.011 4.718 (3) (1) 0.013 (3) 0.018 (7 0.005 5.833 (3) (1) 0.198 (3) 0.014 (2) 0.016 (1 0.004 16.968(2) 5.252 (1) (3) 0.192 (2) 0.021 (1) (6 0.013 0.007 4.672 16.707(1) (3) (2) 0.176 (1) (15 0.004 (1) 0.015 4.561 V17 0.009 16.914(2) (2) (1) (4) (78 0.181 (1) 0.007 0.007 4.478 0.014 V16 16.701(1) (1) (4) (1) (3) (49 0.186 0.008 0.025 0.019 4.567 V14 16.867(1) (4) (1) (3) 0.032 (1) 0.211 0.016 0.009 (4) V13 17.020(1) (3) 0.178 (2) 0.053 0.012 16.828(3) (3) V11 (2) 0.202 3.781(2 0.051 17.047(2) 3.850(51 (2) V10 0.229 0.088(4) 17.031(1) 0.108(7) 4.092(30 V8 0.146(4) 0.145(7) 0.195(4) 0.105(4) 3.674(40 V4 0.177(7) 0.431(4) 0.152(4) 0.054(6) 3.855(21 V3 0.454(7) 17.197(3) 0.211(4) 0.108(6) 0.084(3) 17.066(5) 0.343(4) 0.229(6) 0.131(3) 16.941(2) V12 0.413(5) 0.164(3) 17.089(4) V7 0.440(3) 17.066(2) V6 V2 V1 Variable D( ID h ubr nprnhssidct h netit ntel the in uncertainty the indicate parentheses in numbers The 6 hsRa trhspoone Blazhko pronounced has star RRab This V6. cer- on comment we paragraphs following the In D m tr[Fe/H] Star .NTSO NIIULSTARS INDIVIDUAL ON NOTES 5. 1 19(3 20(6 .3(9 .5()1668 19.07 18.41 1.686(8) 18.54 1.677(6) 3.856(4) 19.44( 0.535(19) 1.702(4) 3.861(1) 1.682(2) 0.558(15) 3.858(1) -2.01(36) 3.861(1) 0.496(10) -1.60(56) -1.95(33) 0.546(5) -1.70(26) -1.65(47) -1.72(30) -1.72(21) V17 -1.74(24) V14 V11 V10 4-.14)-.65)0501)3821 .7()19.55( 18.88(4 1.676(6) 1.652(2) 3.862(1) 3.869(1) 0.560(14) 0.620(5) -1.96(56) -1.49(35) -1.91(41) -1.57(31) V4 V3 o h Rbstars. RRab the for σ V A a)( mag) 0 ORE OFIINSO RbADRcSASI G 4147. NGC IN STARS RRc AND RRab OF COEFFICIENTS FOURIER V − m 1.72(13) ± aitos F4etmtda estimated AF04 variations, 0.15 V ZW A a)( mag) 1 HSCLPRMTR FTERcSTARS. RRc THE OF PARAMETERS PHYSICAL [Fe/H] − V m .81)0513 .6()1611 90()05()4.30 0.52(1) 19.05(3) 1.671(1) 3.861(1) 0.571(3) 1.68(16) V ± 0.15 A The . a)( mag) VES UV 2 V m V mod- ± A a)( mag) M 3 0.040 AL 4 TABLE AL 5 TABLE V V RRab RRc s eia places. decimal ast A log ± ermnmmlgt h ih uv fSS5i of is SCS05 of curve light data The spurious ampli- four light. of large minimum presence very near the a to due shows likely but tude, incomplete rather is eywell. very rladrgtpnl n a e httesinusoidal cen- the the that see In can with one model AF04. panels right of and estimation well tral very original agrees cal- the which We 67.46d with 4. of Figure periodicity of a panel culate first in shown are ulations mag) s eia lc.As itdi h eito parame- deviation the is listed Also place. decimal ast 4 0.004 1.I h ae fA0 the AF04 of paper the In V12. T eff log( φ ± P 21 0.016 L/ 67 = 1 .9 72 .8 (589) 5.884 (159) (712) 2.713 3.490 11) (99) (732) 3.902 1.988 20) (230) (605) 3.879 5.861 (185) 73) (204) 2.242 2.053 01) (95) 4.243 93) )7934)6016)20.5 6.071(61) 7.933(41) 9) )366(1)214(181) 2.124 (118) 3.616 3) L )259(0)132(680) 1.342 (606) 2.599 7) .2(9 .8(2 12.4 5.686(92) 22.7 6.241(62) 7.722(69) 8.4 5.435(126) 16.7 8.314(45) ) 5.864(45) 7.581(73) ) 7.981(31) ) ) .7 22 .1 (209) 0.413 (242) (262) 1.979 0.942 ) (188) 2.470 ) ⊙ . ) 6 osfi the fit does 46d * D φ ± 31 (kpc) 0.46 1)04()4.54(4) 0.49(3) 4.38(3) (17) 4.58(2) 0.49(1) 0.48(1) (13) (8) 3 .21 4.37(3) 0.62(1) 13) )05()4.42(1) 0.51(1) 5) .91 4.12(2) 0.59(1) ) * M/ ± V 0.06 m φ M V 41 modulations ⊙ ih curve light R/ ± 0.16 D R (1) m ⊙ © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México edo G 17 h edsz nteupradlower and upper the in size 6 field the is The in frames variables 4147. known NGC all of of field charts Identification 3. Fig. o.I h rsn ae the paper present compan- the unseen In an of ion. by presence attributed possible the bottom, to flat SCS05 a with amplitude smaller right. the to is East and up is North frames hto C0.Acmaio falaalbedata in- available colour The all weighted modulations. tensity of amplitude comparison small to A some similar suggest amplitude SCS05. an of with that complete, and clean is × n 1.5 and 6 × . arcmin 1.5 h V h − i V ih uv Fgr 2) (Figure curve light 2 I epciey nboth In respectively. i rmordt is data our from G 17REVISITED 4147 NGC ih uvsaesoni iue n .I h lat- the In the 5. and include 2 we Figures ter in shown are curves light ihta fSS5 h eutn phased resulting The agreement SCS05. excellent of in that we 0.408318d, data with of paper Com- period present a the noisy. found and somewhat SCS05 is AF04, curve bining light resulting that commented the but 0.408319d of period investigation a calculated their in SCS05 modulations. amplitude in it omit strip. to instability distribution the chose RRab-RRc in we esti- the involving star, colour discussion the peculiar the in this uncertainties of is mode the mates fundamental SCS05 in Given the falls from to star region. star colour the the moves The which 7) 0.48 (Figure region. CMD inter-mode the the in and 0.340 * a esuiu ie h mltd n hs vari- phase and amplitude ations. first the position given the its spurious falls of but be edge It may 7), red (Figure the of strip SCS05. red instability overtone the by to noted mag 0.02 also about was which phasing, out. unseen ruled an be by cannot contamination also light companion Possible available high V13. presently dense not for are requires that observations frequencies 2018). quality two al. et NGC the Ferro in Arellano Detecting 2017; V37 of al. them et case (Smolec of the 6362 one to least similar at non-radial, and modes being frequencies, two similar of very interference of the alternative An be might modes. two explanation the identify but of to modes interference failed pulsation they erratic of overtone these first consequence and that the fundamental SCS05 be by may suggested phasing displacements. been phase has and It amplitude displays curve SeFgr 3). Figure (See ANTD AITO TMAXIMUM AT VARIATION MAGNITUDE 1.Ti R trwsntdb F4t show to AF04 by noted was star RRc This V13. 1.Smlryt 1,ti trsoserratic shows star this V13, to Similarly V16. NV U OBAHOEFFECT. BLAZHKO TO DUE V6 IN 462.2 16.246 16.666 16.175 16.618 16.607 16.148 2456029.223 16.400 2455988.398 16.140 2455963.366 2452818.382 2452813.481 2452791.514 2452770.192 2452654.935 HJD max V AL 6 TABLE aafo C0.The SCS05. from data V V V * and light V 331 M I © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México f6.6.Teclrfiuecnb iwdonline. viewed be can figure color The 67.46d. of ftssfrsvrldt lcsadfudta the that found series and a blocks performed what data have then several We so for if tests be. and of might periodic period is arises star the now question the The whether the star. is dim- doubt the clear beyond of demonstrates the nature variable This shows middle 2012. star, top the in the the ming in of 6, panel Figure brightening the In long-term while 1. the taken Table shows paper in present panel detailed the as of 2012 and data in January the between and nights 2003, July, 24 from during data the taken instruments, AF04 of and assortment 1983 an between by taken 2003 SCS05 convincing of a data find historical to employing the to case star the failed reconsidered but the have We giant variability. considered red discarded bright who later a SCS05, and be RRc by possible classi- variable was a as star as The AF04 by region. fied central the near cluster online. viewed be from can data figure color are The black and paper. AF04 present from the are red SCS05, from 5. Fig. the of modulation amplitude the shows panel left The 4. Fig. AL. ET FERRO ARELLANO 332 eta n ih aestetm cl ntehrzna axis horizontal the in scale symbol time black the and panels (AF04) right 2003 and from central observations are symbols red 1.Ti stebihetsa ntefil fthe of field the in star brightest the is This V18. V ih uv fV3 re ybl r data are symbols Green V13. of curve light sHAD is ta.19) o h aeo ietcomparison direct of sake applied the we decomposition For Fourier of results 1993). the with al. et ecno calculate cannot we h ore eopsto fRcsasis stars RRc of decomposition 19.05 Fourier the to unable were we pixel thus photometry. bad chip, reliable a any to CCD secure near our very and of images column our of edge the available. esti- become better data be accurate to semi- new is when a semi-period mated or as variation characteristic star of whose time the (SR) variable classify late-type we red regular the the evidences Based of on these SCS05. tip by star the on out near the pointed is as (RGB) plot star branch The giant to 7. able Figure of were CMD we SCS05 from fthe of ae hw h ih uv hsdwt hsperiod. this with phased bottom curve The light 24.8d. the shows period, panel of that period half available a about all by of suggests combination phased the well 46.1d; are about data 2012 and AF04 log(0 ihlog with aea ta.(2004): al. et Catelan V r 02osrain rmtepeetwr.I the In work. present the from observations 2012 are s m h itnet G 17otie from obtained 4147 NGC to distance The near is SCS04 by discovered star RRc This V19. lofrteR ya tr n a aeuse make can one stars Lyrae RR the for Also h tri auae nour in saturated is star The − .DSAC ONC44 RMITS FROM 4147 NGC TO DISTANCE 6. . antd nV hsdwt eido 67.46d; of period a with phased V6 in magnitude ± 3 0 + f 638 425.3 n h iuodlcrehsaperiod a has curve sinusoidal the and 2452654.935 M P .6kpc. 0.46 - I Z L 0 = [ = eainfrthe for relation . M/H 471 . 6)adlgf=[ = f log and 362) AIBESTARS VARIABLE − ] V-I 1 − . 3 log 132 1 dpigthe Adopting . . 6 n [ and 765 I P antd eie by derived magnitude I 0 + bn mgs hence images, -band M/H . 0 log 205 α F](Salaris /Fe] [Fe = ] h V i Z, and V / H] data h (3) I − i © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México h tra eirglrrdvral fteS type. SR the online. of viewed variable be can red figure semi-regular color classify a We The as 24.8d. of shows star period panel a the bottom with demonstrates The phased curve This star. light the the dimming. of nature light variable that slow from the data a 2012 data the show of are enlargement clearly paper. an present circles is the panel Green from middle black The and AF04 years. over from brightening red 27 SCS05, term nearly long last a the shows the panel in Top variations V18. light star Historical 6. Fig. V bn fthe of -band G 17REVISITED 4147 NGC hr [ where R tr nTbe5adfudama itneof distance mean a found and 5 Table 18.89 in stars RRc 6 ino aai ass (1997): Cassisi an calibra- & as the the Salaris RGB using use of estimated the to tion be of is can idea tip which the the indicator, de- brief, in of In described magnitude is bolometric papers. it and these M5, Arellano in for and tail (2016) 6229 NGC al. for Are- et (2015) Ferro group e.g. al. our clusters et by other Ferro of applied llano estimates been distance already the has for 1993) (Lee al. de- nearby et type, to originally distances SR method, estimate The of to TRGB. veloped variable the red near semi-regular sits and a is fact the V18 of of advantage tip that take the can We near (TRGB). variables RGB the the using is distance cluster results. h bv qain othe to equations above the n colour ing o [ = f log smre.Alvral tr r lte using plotted are variables stars known variable all All means of intensity-weighted their location marked. the is where 7, ure of (1996) kpc. Harris 19.05 by of SCS05 listed by and values kpc 19.3 the kpc. with 19.08 true of ment distance the a below find we mag we star case 0.14 this is RRc in into V18 the TRGB, distance that from this assume bring results find must To the we it unlikely, with kpc. that is 20.3 agreement assume which of we TRGB, distance the if the a on at 4147, stars exactly NGC is brightest in V18 the and For 0.05 than RGB. between brighter be to mag may According 0.16 TRGB the distance. authors be the these of not overestimation might of leading an dimmer, RGB analysis somewhat to the but their TRGB on in the at stars (2013) exactly brightest al. the et M5, Viaux by argued 20Gr ehv dpe 20Grwt h aim CMD. the our with on Gyr isochrone virtually 12.0 an estimated adopted are overplotting (2005) have of 4147 We al. NGC et Gyr. Angeli and 12.0 De M3 argued M3 have For of SCS05 identical. ages as hand, (2005) other the the that al. On et Gyr. Angeli 12.23 De by approach differential M bol npicpe nte praht siaethe estimate to approach another principle, In h M ftecutri hw nFig- in shown is cluster the of CMD The agree- excellent in are above found distances The h g fNC44 a enetmtdvaa via estimated been has 4147 NGC of age The tip ± = .7kc ngo gemn ihteFourier the with agreement good in kpc, 0.57 M/H − α F](aai ta.19) oee,as However, 1993). al. et (Salaris /Fe] h 3 .TECDO G 4147 NGC OF CMD THE 7. V . 949 [Fe = ] h − i − I 0 i . . / 7 [ 178 H] − M/H log(0 I 0 + ] esrmnso the of measurements h . V 3 0 + f 638 i . 0 [ 008 n correspond- and M/H . 6)and 362) ] 2 , 333 (4) © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México epciey ..temdlprmtr closely [Fe/H]= parameters determinations model our the stars to RRab and correspond RRc i.e. the from calculated respectively, sections reddening and previous distance in the to according =.5ad[ and Y=0.25 oadsac f1.5kcand kpc 19.05 of distance a to y,Y02 n [ and Y=0.25 Gyr, rmVneBr ta.(04 o [Fe/H]= for (2014) al. et VandenBerg from uyrdee.Setx o icsin h oo gr a b can figure color The discussion. a for text See reddened. duly E 19 n F/]–.0fo h itn fHri (1996, Harris of listing the from [Fe/H]=–1.80 ing h G u al oterdb bu .5mag assuming 0.05 that about Note by 7). fit red Figure not the E in does to isochrone isochrone falls (blue the but RGB exercise: the this from out nteH steeprclrdeg ftefis vroeinstab overtone first the of edge red empirical the is HB the in oprsn h re emne scrn sfr[Fe/H]=–2. for is isochrone segmented green the comparison, r:bu n re ice RbadRcsas respectively our in stars, saturated RRc is and V18 RRab Since circles symbol. green red and blue are: fterlgtcre.Vralsaepotduigterint a their for using colors plotted and are magnitudes Variables plotted curves. The light 4147. their NGC of of CMD 7. Fig. AL. ET FERRO ARELLANO 334 ( ( . B B 5kc(paetdsac ouu f1.3 and 16.43) of modulus distance (apparent kpc 05 ehv lte h scrn n ABmodels ZAHB and isochrone the plotted have We − − V V =.2wudmk hnswre Adopt- worse. things make would )=0.02 0 = ) α F]04 h oeswr shifted were models The /Fe]=0.4. . 1 meit euirte stand peculiarities Immediate 01. α F]04frmtliiis–.5(le n 18 rd,and (red), –1.80 and (blue) –1.75 for /Fe]=0.4 E ( B − V 0 = ) I mgsw sdtevle fSS5t lttesa.Isochrone star. the plot to SCS05 of values the used we images . V12 1cm rmtemdlcleto fVneBr ta.(2014) al. et VandenBerg of collection model the from come 01 − − 1 1 . . 72, 75, V16 niywihe means ensity-weighted n assuming and 0 lt ti t( at strip ility e tteRB o h aeo oprsnw plot- we and comparison [Fe/H]=–2.0 of for isochrone sake the the bet- ted For to RGB. [Fe/H] the lower much fit a ter distance claim this to with reddening, necessary, and be (red would little It a only isochrone). improves situation the edition) 2010 a enosre nohrcutr.I eaotan adopt we If clusters. other it where in exactly observed falls the been CMD, i.e. has the correct mode, in overtone are line first black the positions vertical of Lyrae edge red RR the mag. the since 0.1 that about redder stress by a model We at down theoretical bends the HB than the colour of tail blue the parameters. tinue, determined our with odds at at fit better is gives it it RGB, While isochrone). dashed (green h RsasV8adV0aesonwt filled a with shown are V20 and V18 stars SR The . iwdonline. viewed e fw oka h AB h euirte con- peculiarities the ZAHB, the at look we If lnnvral tr r antd-egtdmeans magnitude-weighted are stars non-variable ll V V20 E − ( h I B V ) h ABfr[eH=17,shifted [Fe/H]=–1.75, for ZAHB the 0 i − ≈ and V 0 0 = ) . 5(rlaoFroe l 2016) al. et Ferro (Arellano 45 h V h − i . .Tebakvria line vertical black The 0. V18 I i ybl n colors and Symbols . E ( B − V o 12 for s )=0.0 For . © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México h aeo lans eol ipa aatcglob- Galactic 9. display Figure only For in we ulars (2009). is clearness Catelan of region of sake in- 3 This Table the for in figure systems, listed (1994). the those extragalactic stance in by al. lines populated et solid mostly Oosther- Bono the the Pe˜na by by of shown Contreras calculated limits are 2009, lower gap and Catelan hoff upper 1994, The (e.g. 2018). al. in galaxies et present spheroidal Bono not and is clusters which in have extragalactic dichotomy clusters, figure Oosterhoff globular the this Galactic illustrate of to versions used Similar been indicated. are ly h oiin fGlci lblrcutr on clusters dis- 9 globular Figure Galactic strip. of the instability positions inside the the blue, of the plays red to the HB the to on and stars of number the ing t Bsrcueprmtie ytequantity the by parametrised structure L HB its offered. being were of Fig- favour cluster in Oo-Int their arguments which an (black 2018; for for 10) II distribution and al. 9 Oo the Pe˜naures et and of (Contreras us parabola) 6402 reminds NGC (red This about I Oo distribution more parabola). for is dual stars loci a RRc the displays of distribution (Cacciari and The cluster suggestive 2005). globular M3 al. lo- the et I from Oo whether defined the distribution towards cus not preferentially their confined is are from it stars they decide RRab modulations, to of amplitude possible number strong low their the and Given in caption. shown the the is 4147 in NGC 8 for Figure diagram, period-amplitude Bailey The or stars. plane, RRab known five its on 0 yia fO Icutr.Terao o hsis this for stars, RRab reason its The of period clusters. average low II the Oo of typical nteltrtr o ietcmaio.Acompari- A ( the comparison. with direct son a for literature the in ovd tteepneo agrrdad hf of shift redwards larger a of isochrone. the expense the at solved) r dca addanlnsadaentsuitable not models. are theoretical ZAHB with and and comparison lines for isochrone hand-drawn their fiducial since are illustrative not is E ag rcino R stars, rather RRc the of of and fraction metallicity low large its of spite in cluster . 524 ( ( = B .OSEHF YEADTEH OF HB THE AND TYPE OOSTERHOFF 8. nte neetn etr fNC44 is 4147 NGC of feature interesting Another ehv o on ( a found not have We G 17hsbe osdrda nO type I Oo an as considered been has 4147 NGC L − B [eH ln.Tedffrn otro types Oosterhoff different The plane. -[Fe/H] ± V − 0 f00 h rbe slsee ntfully (not lessened is problem the 0.02 of ) . 4 ,wihufruaeyi ae only based is unfortunately which d, 048 R ) / 8.1 B ( B − VI h otro Type Oosterhoff The . + V bns h eal r ie in given are details The -bands. n ( and ) V + G 4147 NGC R V with ) B − − N I I c M o G 4147 NGC for CMD ) M’ rmSCS05 from CMD’s ) / ( B N , c V + , R N represent- , ab 0 = ) G 17REVISITED 4147 NGC h P ab i . 67, = etwt h lsicto ftecutra nOo- distributions. an amplitude as stars cluster RRc the the from consis- of type and Int classification remarkable the with is tent marginal, although gap, viewed be can from figure are color loci The blue clus- (2013b). The online. OoII al. 6333. the et NGC for Kunder and 2013) 5024 found (2011; was NGC al. ters locus et RRc segmented Ferro of black Arellano In sample the by variables. panel a Blazhko avoiding bottom from clusters, the (2015) OoI five al. in stars et calculated were Ferro (2013a) parabolas Arellano red al. The by et clusters. Kunder OoII by 14 found from (2005). was al. parabola con- and et black evolved Cacciari the The to for according panel loci M3 in the top stars are unevolved the lines stars segmented In and represent RRab tinuous Triangles represent modulations. symbols Blazhko respectively. with open stars, and RRc Filled and 4147. NGC i.8 h eidapiuepaei the in plane period-amplitude The 8. Fig. h oiino G 17isd h Oosterhoff the inside 4147 NGC of position The VI bnsfor -bands 335 © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México ttepsiiiyo nO-n classification. hints Oo-Int stars an RRab et of of possibility (Kains distribution the one the at interesting since an 2015) is dia- al. 4590 period-amplitude NGC The for cluster 1996). young gram which relatively al. and a et [Fe/H] be (Chaboyer its to II for considered Oo HB been an red has 4590 I a NGC Oo with AL. and an ET cluster pupulation; is FERRO type halo which ARELLANO old 6558 the NGC of 2018); whose (Contr- out al. and Pe˜na ruled et cluster eras be cannot Oo-Int also an origin be extragalactic been has to which argued M14, recently attention: our merit gap erhoff the galaxy. during dSph Sagittarius Galaxy satellite our the by that of scenario accreted merging the was supports 4147 2003b), NGC (2003a, al. the et Bellazz- to by ini discussed cluster stream the galaxy dSph of Sagittarius association with together This, 336 h e deo h rtoetn ntblt strip instability overtone at first stars the RRc ( of and at edge RRab suggests the red HB of the the segregation on of stars clean out Lyrae a RR (four of I distribution Oo clusters 2018). some type al. et in II (Yepez only far) Oo so but studied seven far), splitting all so mode in (nine clean found a HB been the since in has interest, stars RRc particular and RRab of of type, distribution Oosterhoff a intermediate has an and HB blue rather edndi iue7 ie h euirte fV12 of ( peculiarities the V16 Given and 7. Figure in reddened r ) hl hsi bevdol nsm oI It I. Oo some in only observed is Fig- this first in while the line 7), of vertical ure modes edge (black the red strip II instability the Oo overtone around all segregated in of well revised, that are have significant is we it clusters Thus, the (2009). de- Catelan in by so addressed tail the is with problem concepts al. second-parameter these et called Silva-Aguirre of connection (e.g. The RGB the the 2008). on in depends rates turn loss stars in mass which ZAHB strip, of instability distribution the mass a in the is of region result “either-or” dis- or direct mode inter-mode mingled the in the tribution versus segregation mode group. the our of type– papers HB recent plane in the observed on as types [Fe/H], Oosterhoff clus- both of of family ters a in observed mode-mixing or splitting clearly HB. are the stars 4147 in overtone NGC segregated of first case and the fundamental in the that conclude can we hence 8.2 rmFgr ,tremr lsesi h Oost- the in clusters more three 9, Figure From xetfrteRcV6adteRa 1,the V12, RRab the and V16 RRc the for Except a with metallicity low of cluster a 4147 NGC shsbe icse yCpt ta.(1978), al. et Caputo by discussed been has As mode- of occurrence the illustrates 9 Figure V-I itiuino ustn oe nteHB the in Modes Pulsating of Distribution . ) 0 0 = § ) ebleete a eoitdand omitted be can they believe we 5), . 5(rlaoFroe l 06 duly 2016) al. et Ferro (Arellano 45 e spitotta G 50i h oI type II Oo RRc the and separated. RRab is well its are 4590 still, stars HB; NGC reddest the that passing with out In cluster point stars. RRc us and al. is let RRab Pe˜na region et inter-mode both Contreras the by by that populated clear paper is the it where in (2018), 4. Figure of ik a seTbe3o aea 2009). Catelan of 3 the Table of (see that satellites Way gap galaxy distri- Milky dwarf Oosterhoff Lyrae to the associated RR in been the have clusters revise those to of interest butions of be would online. a uprstepsiiiyo netaaatcorigin. extragalactic an of Oosterhoff possibility the See inside the position is supports Its it (see gap class but blue). this cluster in in HB 4147 I labels bluest Oo NGC cluster the with poor one (1994). metal the not most obviously al. the et as Bono out Oost- the stands to of according limits the gap are lines erhoff The solid lower (2018). and group. Pe˜na al. upper Contreras our et The from by adapted is studied Empty M14 yet of case symbols. not clusters non-rimmed are filled symbols to instability the opposed of as edge red strip, segre- overtone well first are the around modes gated overtone first The and where fundamental respectively. clusters the clusters globular represent halo structure symbols outer black-rimmed HB and inner the for in used clusters globular Galactic parameter 9. Fig. atfo hoeia n miia investigations empirical and known well theoretical a now from is cluster fact globular a of metallicity .NC44 N THE AND 4147 NGC 9. o h aeo 1,w ee othe to refer we M14, of case the For h eedneo h Blmnst nthe on luminosity HB the of dependence The § . o icsin h oo gr a eviewed be can figure color The discussion. a for 8.1 L s F/]pae ice n qae are squares and Circles plane. [Fe/H] vs. M V [eH RELATION -[Fe/H] B − V CMD © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México lc G 17uigorpeetrslsfrteav- the for results present erage our using 4147 NGC place 93 hbyr19) narcn ae (Arellano the studied paper have M we recent 2017) & Giridhar a & In Bramich Demarque Ferro, Sandage Lee, 1999). 1992, Chaboyer al. 1993, et (e.g. Carney 1992, Walker 1990’s, 1990, Zinn the during made online. RRa viewed for be analysis can out figure similar color stands a The by it 2017. obtained and Giridhar slope line) different black the (thick Note trend general the follow rmta fteRcsas nFgr 0w repro- we 10 Figure In stars. the different RRc duce significantly the of is relationship that the stars light from of RRab Lyrae slope from the RR obtained of that the found results We of the curves. decomposition from way, Fourier homogeneous the a in groups eemndb rlaoFro rmc Giridhar 10) & Figure Bramich in (2017). Ferro, line Arellano (red by stars determined RRc when RRab the the relationship from the follow from of calculated slope do results greater the and the Note clusters by stars. I defined Oo trend of general family the with ugse hti a edet h rsneo a of is presence It the the to to data. due similar present frequency be not-yet-identified the may secondary in it seen that also suggested AF04 RRc is by the noticed SCS05, about previously in and V16, of phasing and V13 period Erratic stars cluster. its type and confirmed. the V6 are of of 67.46d metallicity nature calculate and Blazhko and The cer- distance stars discuss mean to individual cluster, the of the in peculiarities stars tain Lyrae RR the of the in i.1.The 10. Fig. V e ieeta C htmtyo G 4147 NGC of photometry CCD differential New [eH eainfrfmle fO n oII Oo and I Oo of families for relation -[Fe/H] M VI V bnsalwdu orvs h ih curves light the revise to us allowed -bands M 0 UMR FRESULTS OF SUMMARY 10. n F/] hs ausaeconsistent are values These [Fe/H]. and V M [eH eainfrteRcsasand stars RRc the for relation -[Fe/H] V [eH eaincluae i h ore eopsto o decomposition Fourier the via calculated relation -[Fe/H] 4147 G 17REVISITED 4147 NGC stems ea eceto l oIgoua clusters. globular I Oo all of deficient metal most the as yti ou si em ob h aefralO II Oo all for clusters. case I the Oo be some separated to for are seems only it stars but as We RRc locus and this clusters. RRab the by other the to of that according analysis found expected similar is from it results where instabil- falls first-overtone the we strip of results, ity edge really red empirical not the relative these that do mag stress for we 0.1 explanation HB While about an the by have of predictions. red tail theoretical too blue to be The to per- found suggesting metallicity. was mag, lower red 0.05 as a the much to haps as fall by RGB work the this of in estimated reddening the ltos ihteetmtdmtliiy n its and metallicity, parameter mod- estimated structure amplitude the HB strong With physical because present ulations. of curves decomposition the light Fourier calculation in their stars the the RRab for via the quantities suitable of is none that cluster argued was It iiyaddsac fteprn lse as cluster parent metal- the the of of distance averages [Fe/H] the and calculated licity we cluster. stars the to can distance TRGB, the the estimate near to star, a used The with be variable 24.8d. SR as about now classified period resolved clearly been star has the surround- V18 Are- with controversy of 2017; status The variable al. 2018). the et ing al. (Smolec et 6362 Ferro NGC llano in V37 of case scrn for isochrone possible its may and which Oo-Int origin. gap as extragalactic Oosterhoff classification its the support in falls marginally tr rdln)fudb rlaoFro rmc & Bramich Ferro, Arellano by found line) (red stars b rmteFuirdcmoiino RRc of decomposition Fourier the From h M ipassm euirte.The peculiarities. some displays CMD The ZW = − ≈ R trlgtcre.NC44 does 4147 NGC curves. light star RRc f 1 [Fe/H] . 72 ± 0 ZW . 5ad19.05 and 15 = L − +0 = 1 . 2 h itneand distance the 72, . 8 G 4147 NGC 38. ± .6kpc. 0.46 337 © Copyright 2018: Instituto de Astronomía, Universidad Nacional Autónoma de México i.11. Fig. AL. ET FERRO ARELLANO 338 aenwietfida 2 n lsie ta SR. as it classified and we V20 which The re- as them, stars of identified RGB one now bright of have five nature variable of the curves vealed light the of tion V20. variable rlaoFro . acr in,P . rmc,D M., D. Bramich, Pi˜na, E., P. Mancera A., Ferro, 2016, Arellano al. et M., D. Bramich, A., et Luna, A., S., Ferro, Arellano Giridhar, R., Jaimes, Figuera A., Ferro, 2017, Arellano S. Giridhar, & M., D. Bramich, A., Ferro, R., Arellano Jaimes, Figuera M., D. Bramich, A., Ferro, Arellano 2004, al. L´azaro, et Ar´evalo, J., C., A., M. Ferro, H., Arellano I. Fierro, Bustos A., J. 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