J/ApJ/808/11 RR Lyrae stars in M4. II. Spitzer/IRAC phot. (Neeley+, 2015)
On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars.
II. Mid-infrared period-luminosity relations.
Neeley J.R., Marengo M., Bono G., Braga V.F., Dall'Ora M., Stetson P.B.,
Buonanno R., Ferraro I., Freedman W.L., Iannicola G., Madore B.F.,
Matsunaga N., Monson A., Persson S.E., Scowcroft V., Seibert M.
<Astrophys. J., 808, 11 (2015)>
=2015ApJ...808...11N 2015ApJ...808...11N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Photometry, infrared ; Clusters, globular
Keywords: globular clusters: individual: M4; stars: distances;
stars: horizontal-branch; stars: variables: RR Lyrae
Abstract:
New mid-infrared (MIR) period-luminosity (PL) relations are presented
for RR Lyrae variables in the globular cluster M4 (NGC 6121). Accurate
photometry was obtained for 37 RR Lyrae variables using observations
from the Infrared Array Camera on board the Spitzer Space Telescope.
The dispersion of M4's PL relations is 0.056, and the uncertainty in
the slope is 0.11mag. Additionally, we established calibrated PL
relations at 3.6 and 4.5µm using published Hubble Space Telescope
geometric parallaxes of five Galactic RR Lyrae stars. The resulting
band-averaged distance modulus for M4 is
µ=11.399±0.007(stat)±0.080(syst)±0.015(cal)±0.020(ext). The
systematic uncertainty will be greatly reduced when parallaxes of more
stars become available from the GAIA mission. Optical and infrared
period-color (PC) relations are also presented, and the lack of an MIR
PC relation suggests that RR Lyrae stars are not affected by CO
absorption in the 4.5µm band.
Description:
The results of our ground-based optical and NIR monitoring of the
stellar population in M4 have been published in Stetson et al. (2014,
J/PASP/126/521) and Braga et al. (2015ApJ...799..165B 2015ApJ...799..165B). In this paper,
we extend our wavelength coverage to the MIR, by including multi-epoch
3.6 and 4.5um photometry of a large portion of the cluster.
Our IRAC observations of M4 were executed on 2013 June 2-3 as part of
the warm Spitzer Space Telescope Cycle 9 (PID 90088). The cluster was
observed at IRAC 3.6 and 4.5um bands at 12 equally spaced epochs over
∼14hr.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 57 444 Photometry for RR Lyrae in M4
table2.dat 105 37 Mean IRAC magnitudes and amplitudes for
the RR Lyrae stars in M4
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/573/A70 : UBVI photometry in 3 globular clusters (Nardiello+, 2015)
J/A+A/563/A80 : Wide field imagers astrometry. V. (Libralato+, 2014)
J/PASP/126/521 : UBVRIJHK photometry of RR Lyrae in M4 (Stetson+, 2014)
J/MNRAS/442/2381 : Variable stars in M4 primary field (Nascimbeni+, 2014)
J/MNRAS/440/L96 : RR Lyrae AllWise photometry (Klein+, 2014)
J/MNRAS/435/3206 : Properties of field RR Lyrae variables (Dambis+, 2013)
J/AJ/145/43 : CASE. V. Three eclipsing binaries in M4 (Kaluzny+, 2013)
J/AcA/62/357 : Proper motions in 6 globular clusters (Zloczewski+, 2012)
J/ApJ/759/146 : Spitzer/IRAC phot. for 37 Galactic Cepheids (Monson+, 2012)
J/ApJ/743/76 : Spitzer photometry of LMC Cepheids (Scowcroft+, 2011)
J/AJ/142/187 : HST obs. of 7 Pop. II variable stars (Benedict+, 2011)
J/A+A/527/A146 : CoRoT 0105288363 light curves (Chadid+, 2011)
J/PASP/121/1378 : Positions of variable stars in GCs (Samus+, 2009)
J/AJ/128/2239 : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)
J/AcA/53/93 : OGLE RR Lyrae in LMC (Soszynski+, 2003)
J/ApJS/120/265 : HST photometry of M4 (Ibata+, 1999)
J/AJ/114/189 : M 4 CCD photometry (Alcaino+, 1997)
J/PAZh/22/847 : Identification and coordinates in M4 (Shokin+, 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- ID RR Lyrae name
6- 14 F9.3 d MJD3.6 ? Modified Julian Date of 3.6 micron observation
17- 22 F6.3 mag 3.6mag [10.4/11.6]? Spitzer/IRAC 3.6 micron band magnitude
26- 30 F5.3 mag e_3.6mag [0.003/0.2]? The 1σ error in 3.6mag
33- 41 F9.3 d MJD4.5 ? Modified Julian Date of 4.5 micron observation
44- 49 F6.3 mag 4.5mag [10.3/11.6]? Spitzer/IRAC 4.5 micron band magnitude
53- 57 F5.3 mag e_4.5mag [0.003/0.2]? The 1σ error in 4.5mag
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- ID RR Lyrae name (1)
5- 6 I2 h RAh Hour of right ascension (J2000)
8- 9 I2 min RAm Minute of right ascension (J2000)
11- 15 F5.2 s RAs Second of right ascension (J2000)
17 A1 --- DE- Sign of declination (J2000)
18- 19 I2 deg DEd Degree of declination (J2000)
21- 22 I2 arcmin DEm Arcminute of declination (J2000)
24- 27 F4.1 arcsec DEs Arcsecond of declination (J2000)
29- 38 F10.8 d Per [0.2/0.9] Period
40- 49 F10.7 [d] logP [-0.7/-0.06] log(P) value
51- 56 F6.3 mag [3.6] [10.4/11.5]? 3.6um band magnitude
58- 62 F5.3 mag e_[3.6] [0.007/0.04]? [3.6] uncertainty
64 A1 --- f_[3.6] [c] Flag on [3.6] (2)
66- 71 F6.3 mag [4.5] [10.4/11.5]? 4.5um band magnitude
73- 77 F5.3 mag e_[4.5] [0.006/0.04]? [4.5] uncertainty
79 A1 --- f_[4.5] [c] Flag on [4.5] (2)
81- 84 F4.2 mag 3.6amp [0.04/0.4]? 3.6um amplitude
86- 89 F4.2 mag e_3.6amp [0.01/0.06]? 3.6amp uncertainty
91- 94 F4.2 mag 4.5amp [0.04/0.4]? 4.5um amplitude
96- 99 F4.2 mag e_4.5amp [0.01/0.06]? 4.5amp uncertainty
101-104 A4 --- Mode RR Lyrae mode ("RRc" or "RRab") (3)
105 A1 --- f_Mode [*] *: candidate Blazhko stars
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Note (1): Name as given in Clement's catalog (<Cl* NGC 6121 SAW VNN> in Simbad),
with the exception of C1, newly named in Stetson et al.
(2014, J/PASP/126/521; <[SBD2014] CN> in Simbad).
Note (2):
c = The uncertainty is derived using the repeatability parameter given
in DAOPHOT.
Note (3): The pulsation mode (RRab = FU (fundamental mode), RRc = FO (first
overtone pulsator)).
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History:
From electronic version of the journal
References:
Braga et al. Paper I. 2015ApJ...799..165B 2015ApJ...799..165B
Stetson et al. Paper III. 2014PASP..126..521S 2014PASP..126..521S, Cat. J/PASP/126/521
Braga et al. Paper IV. 2016AJ....152..170B 2016AJ....152..170B, Cat. J/AJ/152/170
Braga et al. Paper V. 2018AJ....155..137B 2018AJ....155..137B
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-Nov-2015