J/ApJ/598/597 Frequency analysis of fundamental-mode RR Lyrae (Alcock+, 2003)
The MACHO project Large Magellanic Cloud variable star inventory.
XI. Frequency analysis of the fundamental-mode RR Lyrae stars.
Alcock C., Alves D.R., Becker A., Bennett D., Cook K.H., Drake A.,
Freeman K., Geha M., Griest K., Kovacs G., Lehner M., Marshall S.,
Minniti D., Nelson C., Peterson B., Popowski P., Pratt M., Quinn P.,
Rodgers A., Stubbs C., Sutherland W., Vandehei T.,
Welch D.L. (the Macho Collaboration)
<Astrophys. J., 598, 597-609 (2003)>
=2003ApJ...598..597A 2003ApJ...598..597A
ADC_Keywords: Clusters, globular ; Stars, variable
Keywords: globular clusters: general - stars: horizontal-branch -
stars: oscillations - stars: variables: other (RR Lyrae)
Abstract:
We have frequency-analyzed 6391 variables classified earlier as
fundamental-mode RR Lyrae (RR0) stars in the MACHO database on the
Large Magellanic Cloud (LMC). The overwhelming majority (i.e., 96%) of
these variables have been proved to be indeed RR0 stars, whereas the
remaining ones have fallen into one of the following categories:
single- and double-mode Cepheids, binaries, first-overtone and
double-mode RR Lyrae stars, and nonclassified variables. Special
attention has been paid to the properties of the amplitude- and
phase-modulated RR0 stars (the Blazhko stars). We found altogether 731
Blazhko variables showing either a doublet or an equidistant triplet
pattern at the main pulsation component in their frequency spectra.
This sample overwhelmingly exceeds the number of Blazhko stars known
in all other systems combined. The incidence rate of the Blazhko
variables among the RR0 stars in the LMC is 11.9%, which is 3 times
higher than their rate among the first-overtone RR Lyrae stars. No
difference is found in the average brightness between the single-mode
and Blazhko variables. However, the latter ones show a somewhat lower
degree of skewness in their average light curves and a concomitant
lower total amplitude in their modulation-free light curves.
Description:
This paper analyzes RR Lyrae stars identified in 30 LMC MACHO project
fields (1, 2, 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 22,
23, 24, 47, 53, 55, 57, 76, 77, 78, 79, 80, 81, and 82).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 69 6391 Star-by-star comments on the frequency analysis
table3.dat 45 6391 Coordinates and main periods of the variables
table4.dat 196 731 Fourier decompositions of the Blazhko variables
table5.dat 44 725 Variables with multiple identification numbers
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See also:
II/247 : Variable Stars in the Large Magellanic Clouds (MACHO, 2001)
J/ApJ/542/257 : MACHO LMC first-overtone RR Lyrae (Alcock+, 2000)
J/AJ/127/334 : MACHO LMC first-overtone RR Lyrae variables (Alcock+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- MACHO Variable name
15- 19 A5 --- VType Variable type (1)
21- 70 A50 --- Notes Additional remarks
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Note (1): Variable types are written as follows:
. = singly-periodic FU;
BL1 = Blazhko with 1 side component;
BL2 = Blazhko with 2 side components;
PC = Period changer;
D = Peak(s) at n*c/d;
FU/FO = FU/FO Beat Cepheid;
FO/SO = FO/SO Beat Cepheid;
SOCEP = Single-overtone Cepheid (FO or SO);
MI = Miscellaneous (secondary peaks far from f0);
MFC = Non-equidistant frequency components at f0;
BI = Binary;
RR1 = First overtone RR Lyrae;
RRd = FU/FO RR Lyrae;
N = Not classified (few data points, etc.).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- MACHO Variable name
15- 16 I2 h RAh Hour of Right Ascension (J2000)
18- 19 I2 min RAm Minute of Right Ascension (J2000)
21- 24 F4.1 s RAs Second of Right Ascension (J2000)
26 A1 --- DE- Sign of the Declination (J2000)
27- 28 I2 deg DEd Degree of Declination (J2000)
30- 31 I2 arcmin DEm Arcminute of Declination (J2000)
33- 34 I2 arcsec DEs Arcsecond of Declination (J2000)
37- 45 F9.7 d Per Period (1)
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Note (1): Values lower than 0.166667 denote frequencies (1/period).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- MACHO Variable name
15- 22 F8.6 1/d f0 Fundamental frequency (1)
24- 32 F9.6 1/d fm Modulation (Blazhko) frequency (1)
35- 38 I4 --- Num Number of data points
41- 47 F7.4 mag Vmag Average Johnson V band magnitude
51- 56 F6.4 --- sigma Standard deviation of the residuals (=data-fit)
58- 63 F6.4 mag a1 First Fourier amplitude (1)
65- 70 F6.4 mag a2 Second Fourier amplitude (1)
72- 77 F6.4 mag a3 Third Fourier amplitude (1)
79- 84 F6.4 mag a4 Fourth Fourier amplitude (1)
86- 91 F6.4 mag a5 Fifth Fourier amplitude (1)
93- 98 F6.4 mag a6 Sixth Fourier amplitude (1)
100-105 F6.4 mag a7 Seventh Fourier amplitude (1)
107-112 F6.4 mag a8 Eighth Fourier amplitude (1)
114-119 F6.4 mag a9 Ninth Fourier amplitude (1)
121-126 F6.4 mag a10 Tenth Fourier amplitude (1)
128-133 F6.4 --- fi1 First Fourier phase (1)
135-140 F6.4 --- fi2 Second Fourier phase (1)
142-147 F6.4 --- fi3 Third Fourier phase (1)
149-154 F6.4 --- fi4 Fourth Fourier phase (1)
156-161 F6.4 --- fi5 Fifth Fourier phase (1)
163-168 F6.4 --- fi6 Sixth Fourier phase (1)
170-175 F6.4 --- fi7 Seventh Fourier phase (1)
177-182 F6.4 --- fi8 Eighth Fourier phase (1)
184-189 F6.4 --- fi9 Ninth Fourier phase (1)
191-196 F6.4 --- fi10 Tenth Fourier phase (1)
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Note (1): The Fourier decompositions of the V light curves have been computed
by fitting the following trigonometric sum by the method of standard
Least Squares:
V(t) = Vmag + a1*sin(2*pi*f1*(t-t0)+fi1)
+ a2*sin(2*pi*f2*(t-t0)+fi2) + ...
and t is HJD-2400000.0 in days, Vmag is the Johnson V band average
magnitude, pi = 3.141593..., t0 = 0.0 days, f1 = f0 - |fm|,
f2 = f0, f3 = f0 + |fm|, f4 = 2*f0 - |fm|, f5 = 2*f0,
f6 = 2*f0 + |fm|, f7 = 3*f0, f8 = 4*f0,f9 = 5*f0, and f10 = 6*f0.
fm > 0, if a3 > a1
fm < 0, if a3 < a1
Outliers have been omitted by an iterative 3*sigma procedure. The
First 400 variables are BL1 stars, the remaining 331 are of BL2 type.
Variables with multiple MACHO IDs are included.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- MACHO Variable name
15- 23 F9.7 d Per Period
25- 26 I2 h RAh Hour of Right Ascension (J2000)
28- 29 I2 min RAm Minute of Right Ascension (J2000)
31- 34 F4.1 s RAs Second of Right Ascension (J2000)
36 A1 --- DE- Sign of the Declination (J2000)
37- 38 I2 deg DEd Degree of Declination (J2000)
40- 41 I2 arcmin DEm Arcminute of Declination (J2000)
43- 44 I2 arcsec DEs Arcsecond of Declination (J2000)
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History:
From electronic version of the journal
References:
Alcock et al., Paper I 1996ApJ...461...84A 1996ApJ...461...84A
Alcock et al., Paper II 1996AJ....111.1146A 1996AJ....111.1146A
Alcock et al., Paper III 1997ApJ...482...89A 1997ApJ...482...89A
Alcock et al., Paper IV 1996ApJ...470..583A 1996ApJ...470..583A
Alcock et al., Paper V 1997AJ....114..326A 1997AJ....114..326A
Alcock et al., Paper VI 1996ApJ...470..583A 1996ApJ...470..583A
Alcock et al., Paper VII 1998AJ....115.1921A 1998AJ....115.1921A
Alcock et al., Paper VIII 1999AJ....117..920A 1999AJ....117..920A
Alcock et al., Paper IX 2000ApJ...542..257A 2000ApJ...542..257A, Cat. J/ApJ/542/257
Alcock et al., Paper X 2001ApJ...554..298A 2001ApJ...554..298A
Alcock et al., Paper XII 2002ApJ...573..338A 2002ApJ...573..338A
Alcock et al., Paper XIII 2004AJ....127..334A 2004AJ....127..334A, Cat. J/AJ/127/334
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 16-Jan-2004