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J/ApJS/193/8     Spectroscopy of 26 lensing cluster cores       (Bayliss+, 2011)

Gemini/GMOS spectroscopy of 26 strong-lensing-selected galaxy cluster cores. Bayliss M.B., Hennawi J.F., Gladders M.D., Koester B.P., Sharon K., Dahle H., Oguri M. <Astrophys. J. Suppl. Ser., 193, 8 (2011)> =2011ApJS..193....8B
ADC_Keywords: Redshifts ; Clusters, galaxy ; Gravitational lensing ; Spectroscopy ; Velocity dispersion Keywords: galaxies: clusters: general - gravitational lensing: strong Abstract: We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS; Gladders et al. 2011, in prep) and the Second Red-Sequence Cluster Survey (RCS-2; Bayliss et al. 2011, in prep). The 26 galaxy cluster lenses span a redshift range of 0.2<z<0.65, and our spectroscopy reveals 69 unique background sources with redshifts as high as z=5.200. We also identify redshifts for 262 cluster member galaxies and measure the velocity dispersions and dynamical masses for 18 clusters where we have redshifts for N≥10 cluster member galaxies. We account for the expected biases in dynamical masses of strong-lensing-selected clusters as predicted by results from numerical simulations and discuss possible sources of bias in our observations. Description: We observed a sample of 26 clusters with the Frederick C. Gillett Telescope (Gemini North) between 2008 February and 2010 June as part of Gemini programs GN-2008A-Q-25 and GN-2009A-Q-21. We obtained pre-imaging of 20 of the 26 clusters in gri with the Gemini Multi-Object Spectrograph (GMOS). In addition to the Gemini/GMOS-North spectroscopy, we supplement our data set with cluster member redshift measurements made at the 3.5m Astrophysical Research Consortium (ARC) Telescope at Apache Point Observatory in New Mexico, using the Dual Imaging Spectrograph (DIS) in long-slit mode. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 67 27 Summary of spectroscopic observations table2.dat 56 69 Individual lensed sources table3.dat 41 26 Properties of the galaxy cluster lenses table4.dat 57 405 Individual redshifts measured with Gemini/GMOS
See also: II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) VII/110 : Rich Clusters of Galaxies (Abell+ 1989) J/MNRAS/406/1318 : Lensed-arc statistics of galaxy clusters (Horesh+, 2010) J/ApJ/690/670 : The Sloan lens ACS Survey. VIII. (Treu+, 2009) J/ApJ/668/643 : Multiply imaged gravitational lens systems (Limousin+, 2007) J/PAZh/33/403 : Globular clusters as gravitational lenses (Bukhmastova+, 2007) J/ApJ/641/169 : Spectroscopy in lens fields (Momcheva+, 2006) J/ApJS/157/1 : Red-Sequence Cluster Survey (Gladders+, 2005) J/ApJS/158/161 : Photometric redshift catalog from the RCS (Hsieh+, 2005) J/AJ/126/119 : Optical and radio data for rich Abell clusters (Rizza+, 2003) : SDSS home page Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 17 A17 --- Core Target identification (G1) 19- 21 A3 --- n_Core [c-j, ] Individual notes on target (1) 23- 24 I2 h RAh BCG centroid hour of right ascension (J2000) (2) 26- 27 I2 min RAm BCG centroid minute of right ascension (J2000) 29- 33 F5.2 s RAs BCG centroid second of right ascension (J2000) 35 A1 --- DE- BCG centroid declination sign (J2000) (2) 36- 37 I2 deg DEd BCG centroid degree of declination (J2000) 39- 40 I2 arcmin DEm BCG centroid arcminute of declination (J2000) 42- 45 F4.1 arcsec DEs BCG centroid arcsecond of declination (J2000) 47- 51 A5 --- Prog Semester observation program id (3) 53 I1 --- mult Exposure multiplicator 54 A1 --- --- [x] 55- 58 I4 s Exp Exposure time 60 I1 --- mult2 ? Exposure multiplicator for 2d exposure 61 A1 --- --- [x] 62- 65 I4 s Exp2 ? 2d exposure time 67 A1 --- f_Exp [fg] Flag on exposures (4)
Note (1): Flags as follows: c = This cluster was first identified by Abell et al. (1989, Cat. VII/110). d = Cluster appears in the ROSAT all-sky bright source catalog (Voges et al. 1999, Cat. IX/10). e = Also a MACS cluster (Ebeling et al. 2001ApJ...553..668E). h = SDSS J1209+2640 was observed in both semesters with two different masks. i = SDSS J1226+2152 and SDSS J1226+2149 are two strong-lensing cores in a larger complex structure. One mask for each core was designed from the same pre-imaging data. j = Cluster first published by Gunn et al. (1986ApJ...306...30G). Note (2): calibrated against the SDSS. Note (3): Details of the instrument configuration for each semester can be found in Section 2.3. Note (4): Flag as follows: f = Some N&S exposure sequences were terminated partway through due to deteriorating conditions at the telescope. g = We have only one N&S science exposure for SDSS J1209+2640 and SDSS J1115+5319, limiting our ability to correct for chip gaps, chip defects, charge traps, and cosmic rays.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 17 A17 --- Core Cluster core identification (G1) 19 A1 --- Label Background source label (1) 21- 26 F6.4 --- z GMOS spectroscopic redshift (2) 28- 29 I2 --- l/w ? Length-to-width ratio (3) 31 A1 --- f_l/w [f] Remark if l/w=1 (4) 33- 36 F4.1 arcsec Rarc ? Mean distance from a giant arc to the BCG of the lensing cluster 38 A1 --- Band Band (g, r or i) 40- 44 F5.2 mag mag Integrated AB magnitude in Band (5) 46 A1 --- r_mag [eg] mag reference (6) 48- 56 A9 --- Class Classification (7)
Note (1): Source labels matching those in Figures 5-11 and Table 4. Note (2): Table 2 contains a list of all unique background sources with secure redshifts from GMOS spectroscopy. It does not include any sources for which we do not have precise redshift measurements. Note (3): Length-to-width ratios are all estimated from ground-based imaging with variable seeing. In the case of multiple arcs/images, the largest l/w ratio is given. Note (4): f = this object has l/w=1, but we spectroscopically confirm multiple images of the source separated by ∼13". Note (5): The magnitudes are simple integrated aperture magnitudes of the brightest contiguous image or arc for a given background source, where apertures are drawn by eye to match the morphology of the arcs/sources. The photometry is calibrated relative to stars in the SDSS and are intended only to give a rough sense of the brightness for a given source. These magnitude measurements have typical errors of ∼0.1mag, and we emphasize that the aperture magnitudes can be misleading in some cases. Note (6): Reference as follows: e = Bayliss et al. (2010ApJ...720.1559B) g = Koester et al. (2010ApJ...723L..73K) Note (7): Primary, secondary, or tertiary background source identification, as discussed in Section 3.1
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 17 A17 --- Core Cluster core identification 19- 23 F5.3 --- z ? Spectroscopic redshift 25- 26 I2 --- NMm ? Number of members (5) 28 A1 --- f_NMm [b] Additional members (6) 30- 33 I4 km/s Sigma ? Velocity dispersion 35- 37 I3 km/s E_Sigma ? Positive error on Sigma 39- 41 I3 km/s e_Sigma ? Negative error on Sigma
Note (5): Number of spectroscopic cluster members, including galaxies with spectroscopy publically available from the SDSS DR7 (Cat. II/294). Note (6): the flag means that the count includes 10 additional cluster member redshifts taken from various published studies of A1703: * Allen, S.W. et al. 1992MNRAS.259...67A; * Rizza et al. 2003, Cat. J/AJ/126/119; * Richard et al. 2009A&A...498...37R.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 17 A17 --- Core Cluster core identification 19- 21 A3 --- Label Source label; e.g. Figures 5-11 23- 24 I2 h RAh Hour of Right Ascension (J2000) (1) 26- 27 I2 min RAm Minute of Right Ascension (J2000) (1) 29- 34 F6.3 s RAs Second of Right Ascension (J2000) (1) 36 A1 --- DE- Sign of the Declination (J2000) (1) 37- 38 I2 deg DEd Degree of Declination (J2000) (1) 40- 41 I2 arcmin DEm Arcminute of Declination (J2000) (1) 43- 48 F6.3 arcsec DEs Arcsecond of Declination (J2000) (1) 50- 55 F6.4 --- z ? Spectroscopic redshift 57 I1 --- q_z Redshift class (2)
Note (1): Coordinate astrometry calibrated relative to the SDSS. Note (2): Each redshift measurement falls into one of four classifications (0-3) which describe the confidence level of the redshift as follows: 3 = Highest confidence measurement (typically measured from systems of ≥6 absorption and emission features); 2 = Medium confidence measurement (based on at least two high-significance lines and/or a larger number of low-significance features; redshifts are very likely the real redshifts of the corresponding sources, but there is a small chance that any given class 2 redshift might have been misidentified). 1 = Low confidence measurement (using only a few low-significance spectral features and represent a "best-guess" redshift); 0 = redshift failure.
Global notes: Note (G1): In tables 1 and 2, SDSS J2111-1114 is a misprint for SDSS J2111-0114; corrected at CDS.
Nomenclature notes: In table 4, objects are <[BHG2011] JHHMMSS.sss+DDMMSS.sss> in Simbad. History: * 05-Apr-2011: From electronic version of the journal * 18-May-2011: Names fixed in table2 for coherence with other tables: RCS2 J1055+5547 changed into RCS2 J1055+5548
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 05-Apr-2011
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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