J/MNRAS/494/1237 Blazhko effect in Galactic RR Lyrae II (Skarka+, 2020)
Blazhko effect in the Galactic bulge fundamental mode RR Lyrae stars - II.
Modulation shapes, amplitudes, and periods.
Skarka M., Prudil Z., Jurcsik J.
<Mon. Not. R. Astron. Soc., 494, 1237-1249 (2020)>
=2020MNRAS.494.1237S 2020MNRAS.494.1237S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Milky Way ; Photometry ; Optical
Keywords: methods: data analysis - methods: statistical -
techniques: photometric - stars: horizontal branch -
stars: variables: RR Lyrae
Abstract:
The number of stars observed by the Optical Gravitational Lensing
Experiment (OGLE) project in the Galactic bulge offers an invaluable
chance to study RR Lyrae stars in a statistical manner. We used data
of 3141 fundamental-mode RR Lyrae stars showing the Blazhko effect
observed in OGLE-IV to investigate a possible connection between
modulation amplitudes and periods, light curve, and pulsation
characteristics. We found that there is no simple monotonic
correlation between any combination of two parameters concerning the
Blazhko and pulsation amplitudes, periods, and the shape of the light
curves. There are only systematic limits. There is a bottom limit of
the modulation period with respect to the pulsation period. We also
found that the possible range of modulation amplitudes decreases with
increasing pulsation period, which could point towards that the
Blazhko effect is suppressed in cooler, larger, more luminous, and
less metal abundant bulge RR Lyrae stars. Our investigation revealed
that the distribution of the modulation periods can be described with
two populations of stars with the mean modulation periods of 48 and
186d. There is a certain region with a low density of the modulated
stars, which we call the Blazhko valley, in the pulsation
period-modulation period plane. Based on the similarity of the
modulation envelopes, basically every star can be assigned to one of
six morphological classes. The double modulation was found in 25 per
cent of the studied stars. Only 6.3 per cent of modulated stars belong
to the Oosterhoff group II.
Description:
In Prudil & Skarka (2017MNRAS.466.2602P 2017MNRAS.466.2602P, Cat. J/MNRAS/466/2602), we
found 3341 stars to show the Blazhko effect based on the look of the
frequency spectra and the presence of the equidistant side peaks with
amplitudes above SNR>3.5. This sample was studied again employing
automatic procedures and applying subsequent visual inspection of all
the frequency spectra of the studied stars to discard the stars with
ambiguous modulation. Since we are now interested in the
characteristics of the Blazhko effect, we performed additional data
examination and analysis.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 215 3141 All the important pulsation, modulation,
frequency spectra, and light-curve parameters of
3141 RR Lyrae
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See also:
J/AcA/64/177 : VI light curves of Galactic Bulge RR Lyrae
(Soszynski+, 2014)
J/MNRAS/466/2602 : Blazhko effect in Galactic RR Lyrae (Prudil+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name Star name (OGLE-BLG-RRLYR-NNNNN)
22- 30 F9.7 d-1 f0 Pulsation frequency
32- 40 F9.7 d-1 e_f0 Error on f0
42- 48 F7.5 mag Ares Amplitude of the residuals around the
±0.3c/d vicinity of f0 after removing 10
pulsation components
50- 56 F7.2 --- PBL Modulation period
58- 64 F7.2 --- e_PBL Error on PBL
66- 72 F7.5 d-1 f- Frequency of the left-hand-side peak
74- 80 F7.5 d-1 e_f- Error on f-
82- 88 F7.5 mag A- Amplitude of the left side peak in the
frequency spectrum
90- 96 F7.5 d-1 f+ Frequency of the right-hand-side peak
98- 104 F7.5 d-1 e_f+ Error on f+
106- 112 F7.5 mag A+ Amplitude of the right-hand-side peak
114- 119 F6.3 mag Imean Mean brightness of the star
121- 126 F6.3 mag ImeanMAX Mean brightness during the Blazhko maximum
amplitude
128- 133 F6.3 mag ImeanMIN Mean brightness during the Blazhko minimum
amplitude
135- 139 F5.3 mag Amean Mean amplitude of the light curve
141- 145 F5.3 mag AmeanMIN Amplitude of the light curve during the
minimal-amplitude
147- 151 F5.3 mag AmeanMAX Amplitude of the light curve during the
maximal-amplitude
153- 157 F5.3 mag AenvTOP ? Amplitude of the top envelope
159- 164 F6.3 mag AenvBOT ? Amplitude of the bottom envelope
166- 170 F5.3 --- RTenvTOP Rise time of the top envelope
172- 175 F4.2 --- RTenvBOT Rise time of the bottom envelope
177- 181 F5.3 --- R21 Fourier amplitude coefficient R21
183- 187 F5.3 rad Phi21 Fourier phase coefficient Φ21
189- 193 F5.3 --- R31 Fourier amplitude coefficient R31
195- 199 F5.3 rad Phi31 Fourier phase coefficient Φ31
201- 204 F4.2 --- RTLC Rise time of the mean light curve
206 I1 --- OGroup [1/2] Oosterhoff group (1)
208 A1 --- MorphType Morphological type (2)
210- 215 A6 --- Comments Comments (3)
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Note (1): To divide stars into the Oosterhoff groups, we used a period-amplitude
diagram (see Figure 15 of the article). The black line in Fig. 15
outlines the boundary between Oosterhoff type I and Oosterhoff type II
variables.
Note (2): Morphological type as follows:
a = The top and bottom envelopes are nearly symmetric and sinusoidal and
are close to antiphase. Sometimes the top envelope has a sharp maximum.
b = The Blazhko phase curve is flat during minimal modulation amplitude and
the phase modulation well apparent.
c = The bottom envelope is flat.
d = The bottom envelope has a double minimum.
e = The bottom envelope has a larger amplitude than the top envelope.
f = The top and/or bottom envelope has a bump.
Note (3): Comments as follows:
AdP = Additional peaks
UP = Unresolved peaks, long-term period change
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History:
From electronic version of the journal
References:
Prudil & Skarka, Paper I 2017MNRAS.466.2602P 2017MNRAS.466.2602P, Cat. J/MNRAS/466/2602
(End) Ana Fiallos [CDS] 24-May-2023