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J/AJ/154/85     CTIO/DECam photometry of RR Lyrae stars in M5     (Vivas+, 2017)

Absolute magnitudes and colors of RR Lyrae stars in DECam passbands from photometry of the globular cluster M5. Vivas A.K., Saha A., Olsen K., Blum R., Olszewski E.W., Claver J., Valdes F., Axelrod T., Kaleida C., Kunder A., Narayan G., Matheson T., Walker A. <Astron. J., 154, 85-85 (2017)> =2017AJ....154...85V (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, nearby ; Stars, variable ; Photometry, ugriz Keywords: dust, extinction - globular clusters: individual: M5 - stars: distances - stars: variables: RR Lyrae Abstract: We characterize the absolute magnitudes and colors of RR Lyrae stars in the globular cluster M5 in the ugriz filter system of the Dark Energy Camera (DECam). We provide empirical period-luminosity (P-L) relationships in all five bands based on 47 RR Lyrae stars of the type ab and 14 stars of the type c. The P-L relationships were found to be better constrained for the fundamental-mode RR Lyrae stars in the riz passbands, with dispersions of 0.03, 0.02 and 0.02mag, respectively. The dispersion of the color at minimum light was found to be small, supporting the use of this parameter as a means to obtain accurate interstellar extinctions along the line of sight up to the distance of the RR Lyrae star. We found a trend of color at minimum light with a pulsational period that, if taken into account, brings the dispersion in color at minimum light to 0.016 mag for the (r-i), (i-z), and (r-z) colors. These calibrations will be very useful for using RR Lyrae stars from DECam observations as both standard candles for distance determinations and color standards for reddening measurements. Description: Observations were obtained during 2013 (2013 Jun 7-9, and 2013 Jun 21) and 2014 (2014 Mar 7-9) with the Dark Energy Camera (DECam) imager on the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory (CTIO), Chile. Repeated DECam images of a field centered on M5 (R.A.=15:18:33.2, decl.=+02:04:51.7, J2000.0) were obtained using the u,g,r,i, and z filters. The large field of view (FOV) of DECam (2.2°) easily covers the whole globular cluster with only the central CCDs of the camera. A total of 66 RR Lyrae stars and 1 SX Phe were recognized in the field of M5. The individual measurements for the periodic variable stars are provided in Table2. In Table3, we present the list of periodic variable stars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 34 14516 Individual measurements in ugriz of the periodic variables in the field of M5 table3.dat 127 67 Periodic variable stars identified in the M5 field table4.dat 89 54701 Photometry within a radius of 17.7' from the center of M5
See also: VII/202 : Globular Clusters in the Milky Way (Harris, 1997) J/ApJ/834/160 : ugriz colors of RR Lyrae stars in SDSS Stripe 82 (Ngeow+, 2017) J/other/ApSS/361.175 : M5 RR Lyr and HB VI light curves (Arellano Ferro+, 2016) J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014) J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013) J/ApJ/763/32 : Galactic halo RRab stars from CSS (Drake+, 2013) J/ApJ/632/266 : WFPC2 photometry of the globular cluster M5 (Layden+, 2005) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 6 I6 --- Star [16339/139277] Identification number 8- 19 F12.6 d MJD Modified Julian Date 21 A1 --- Flt [ugriz] Filter (CTIO/DECam u, g, r, i, or z) 23- 28 F6.3 mag mag [14.11/20.74] Apparent magnitude in Flt 30- 34 F5.3 mag e_mag [0.01/0.159] Error in mag
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 6 I6 --- Star [16339/139277] Identification number 8- 9 I2 h RAh Hour of Right Ascension (J2000) 11- 12 I2 min RAm Minute of Right Ascension (J2000) 14- 18 F5.2 s RAs Second of Right Ascension (J2000) 20 A1 --- DE- Sign of the Declination (J2000) 21- 22 I2 deg DEd Degree of Declination (J2000) 24- 25 I2 arcmin DEm Arcminute of Declination (J2000) 27- 30 F4.1 arcsec DEs Arcsecond of Declination (J2000) 32- 38 F7.5 d Per [0.089/0.85] Period 40- 45 A6 --- Type Type of periodic variable (RR Lyrae ab, RR Lyrae c, or SX Phe) 47- 51 F5.2 mag <umag> [15.1/20] Mean magnitude in u band (1) 53- 57 F5.2 mag <gmag> [14.7/19.4] Mean magnitude in g band (1) 59- 63 F5.2 mag <rmag> [14.6/19.3] Mean magnitude in r band (1) 65- 69 F5.2 mag <imag> [14.6/19.3] Mean magnitude in i band (1) 71- 75 F5.2 mag <zmag> [14.5/19.2] Mean magnitude in z band (1) 77- 81 F5.2 mag uref [15.5/20.6]? Magnitude at minimum light in u band (uref) (2) 83- 87 F5.2 mag gref [15/19.8]? Magnitude at minimum light in g band (gref) (2) 89- 93 F5.2 mag rref [14.7/19.5]? Magnitude at minimum light in r band (rref) (2) 95- 99 F5.2 mag iref [14.6/19.4]? Magnitude at minimum light in i band (iref) (2) 101-105 F5.2 mag zref [14.65/19.35]? Magnitude at minimum light in z band (zref) (2) 107-127 A21 --- OName Other name
Note (1): The reported mean magnitudes are not plain averages but were obtained by integrating the best fitted template of the light curve in intensity units, and transforming back to magnitudes. This method of calculating the mean magnitudes avoids the biases toward minimum magnitudes (because the RR Lyrae stars spend most of their pulsation cycle time at minimum light) as well as those biases that may appear as a result of unevenly sampled light curves. Note (2): Measured as explained in Section 5.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 6 I6 --- Star [18709/120853] Identification number 8- 16 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 18- 24 F7.5 deg DEdeg Declination in decimal degrees (J2000) 26- 31 F6.3 mag <umag> [12.45/21.61]? Mean magnitude in u band 33- 37 F5.3 mag e_<umag> [0.002/0.44]? Standard deviation in <umag> (σu) (1) 39- 44 F6.3 mag <gmag> [11.95/22.43]? Mean magnitude in g band 46- 50 F5.3 mag e_<gmag> [0.001/0.36]? Standard deviation in <gmag> (σg) (1) 52- 57 F6.3 mag <rmag> [11.4/22.8]? Mean magnitude in r band 59- 63 F5.3 mag e_<rmag> [0.001/0.31]? Standard deviation in <rmag> (σr) (1) 65- 70 F6.3 mag <imag> [11.7/22.1]? Mean magnitude in i band 72- 76 F5.3 mag e_<imag> [0.001/0.3]? Standard deviation in <imag> (σi) (1) 78- 83 F6.3 mag <zmag> [11.2/21.5]? Mean magnitude in z band 85- 89 F5.3 mag e_<zmag> [0.001/0.68]? Standard deviation in <zmag> (σz) (1)
Note (1): Refers to the standard deviation of the mean of all the measurements for a star in each filter.
History: From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 13-Nov-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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