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J/ApJ/835/184 Globular cluster candidates in NGC4258 (Gonzalez-Lopezlira+, 2017)

The relation between globular cluster systems and supermassive black holes in spiral galaxies: the case study of NGC 4258. Gonzalez-Lopezlira R.A., Lomeli-Nunez L., Alamo-Martinez K., Ordenes-Briceno Y., Loinard L., Georgiev I.Y., Munoz R.P., Puzia T.H., Bruzual G.A., Gwyn S. <Astrophys. J., 835, 184-184 (2017)> =2017ApJ...835..184G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Galaxies, IR ; Photometry, ugriz ; Photometry, infrared Keywords: galaxies: evolution; galaxies: formation; galaxies: individual: NGC 4258; globular clusters: general ; galaxies: spiral; galaxies: star clusters: general Abstract: We aim to explore the relationship between globular cluster total number, NGC, and central black hole mass, M*, in spiral galaxies, and compare it with that recently reported for ellipticals. We present results for the Sbc galaxy NGC 4258, from Canada-France-Hawaii Telescope data. Thanks to water masers with Keplerian rotation in a circumnuclear disk, NGC 4258 has the most precisely measured extragalactic distance and supermassive black hole mass to date. The globular cluster (GC) candidate selection is based on the (u*-i') versus (i'-Ks) diagram, which is a superb tool to distinguish GCs from foreground stars, background galaxies, and young stellar clusters, and hence can provide the best number counts of GCs from photometry alone, virtually free of contamination, even if the Galaxy is not completely edge-on. The mean optical and optical-near-infrared colors of the clusters are consistent with those of the Milky Way and M 31, after extinction is taken into account. We directly identify 39 GC candidates; after completeness correction, GC luminosity function extrapolation, and correction for spatial coverage, we calculate a total NGC=144±31-36+38 (random and systematic uncertainties, respectively). We have thus increased to six the sample of spiral galaxies with measurements of both M* and NGC. NGC 4258 has a specific frequency SN=0.4±0.1 (random uncertainty), and is consistent within 2σ with the NGC versus M* correlation followed by elliptical galaxies. The Milky Way continues to be the only spiral that deviates significantly from the relation. Description: All data for the present work were obtained with the Canada-France-Hawaii-Telescope (CFHT). The optical images of NGC 4258 are all archival, and were acquired with MegaCam. Images were originally secured through programs 08BH55, 09AH42, 09AH98, 09BH95 (P.I. E. Magnier, u*-band); 09AC04 (P.I. R. Lasker, u* and i' filters); 10AT01 (P.I. C. Ngeow, g', r', and i' bands), and 11AC08 (P.I. G. Harris, g' and i' data) spanning 2008 Dec to 2011 Mar. The Ks-band images of NGC 4258 were acquired on 2013 March 27 UT, through proposal 13AC98 (P.I. R. Gonzalez-Lopezlira), with the Wide-field InfraRed Camera (WIRCam). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table6.dat 107 39 Colors of globular cluster candidates table7.dat 103 39 i'-band shape parameters of globular cluster candidates
See also: VII/202 : Globular Clusters in the Milky Way (Harris, 1997) J/AJ/112/1335 : Hubble Deep Field observations (Williams+ 1996) J/A+AS/139/393 : Young Massive Star Clusters. II. (Larsen, 1999) J/MNRAS/343/665 : VI photometry of globular cluster systems (Goudfrooij+, 2003) J/PAZh/33/403 : GCs as gravitational lenses (Bukhmastova+, 2007) J/ApJS/171/101 : GCs in the ACS Virgo cluster survey (Jordan+, 2007) J/ApJ/659/1040 : VLBI monitoring of NGC 4258 (Argon+, 2007) J/ApJ/757/83 : The Blanco Cosmology Survey (BCS) (Desai+, 2012) J/ApJ/772/82 : A catalog of globular cluster systems (Harris+, 2013) J/MNRAS/441/3570 : Nuclear star clusters in 228 spiral gal. (Georgiev+, 2014) Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 3 A3 --- --- [GLL] 5- 18 A14 --- GLL Cluster name (JHHMMSS+DDMMSS) 20- 27 F8.4 deg RAdeg Right ascension in decimal degrees (J2000) 29- 35 F7.4 deg DEdeg Declination in decimal degrees (J2000) 37- 42 F6.3 mag (g')0 [19.1/22.7]? Dereddened CFHT/Megacam g' (AB) magnitude 44- 48 F5.3 mag e_(g')0 ? Error in (g')0 50- 54 F5.2 mag (Ks)0 [18/21.7] Dereddened CFHT/WIRCam Ks (AB) magnitude 56- 59 F4.2 mag e_(Ks)0 Error in (Ks)0 61- 65 F5.3 mag (u*-i')0 [1.5/2.5] Dereddened (u*-i') color index 67- 71 F5.3 mag e_(u*-i')0 Error in (u*-i')0 73- 77 F5.3 mag (g'-r')0 [0.3/0.7]? Dereddened (g'-r') color index 79- 83 F5.3 mag e_(g'-r')0 ? Error in (g'-r')0 85- 89 F5.3 mag (g'-i')0 [0.5/1]? Dereddened (g'-i') color index 91- 95 F5.3 mag e_(g'-i')0 ? Error in (g'-i')0 97-101 F5.2 mag (i'-Ks)0 [-0.3/0.5] Dereddened (i'-Ks) color index 103-107 F5.3 mag e_(i'-Ks)0 Error in (i'-Ks)0
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 3 A3 --- --- [GLL] 5- 18 A14 --- GLL Cluster name (JHHMMSS+DDMMSS) 20- 27 F8.4 deg RAdeg Right ascension in decimal degrees (J2000) 29- 35 F7.4 deg DEdeg Declination in decimal degrees (J2000) 37- 41 F5.2 --- SpMod [-0.3/1.5] 100x(SExtractor SPREAD_MODEL) in the i' band (1) 43- 46 F4.2 arcsec FWHM [0.6/0.9] FWHM in the i' band 48- 51 F4.2 --- S/G SExtractor CLASS_STAR in the i' band (1=star) (2) 53- 56 F4.2 arcsec Rad [0.3/0.7] SExtractor FLUX_RADIUS in the i' band 58 A1 --- l_re Limit flag for half-light radius in the i' band 60- 63 F4.2 pc re [0.7/6] Half-light radius in the i'band 66- 69 F4.2 pc E_re ? Upper error of half-light radius in the i'band 72- 75 F4.2 pc e_re ? Lower error of half-light radius in the i'band 77- 81 A5 --- Shape Type of King profile fitted (KINGn or KINGx) (3) 83- 91 F9.1 --- C Concentration index rtidal/rcore of King profile 93- 98 F6.2 --- SNR [18/338] Signal-to-noise ratio of data 100-103 F4.2 --- Chi2 [0.07/9] Chi2 of fit
Note (1): The SPREAD_MODEL value for each object results from the comparison between its best fitting PSF, and the convolution of such a PSF with an exponential disk with scale length FWHMPSF/16, where FWHMPSF is the full width at half maximum of the same PSF (Desai+ 2012, J/ApJ/757/83). See text for further discussion. Note (2): The SExtractor dimensionless index CLASS_STAR is assigned by a neural network, based on the comparison between the source and the PSF. It goes from 0 for extended objects to 1 for a perfect point source (Bertin & Arnouts 1996A&AS..117..393B; Hammer+ 2010, J/ApJS/191/143). Note (3): We constructed a spatially variable PSF from 172 isolated stars, and we fitted all the sources with King profiles (King 1962AJ.....67..471K, 1966AJ.....71...64K) with fixed (KINGx) concentration indices (C=rtidal/rcore) of 30 and 100, and with the concentration index left as a free parameter (KINGn). See section 6 for further explanations.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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