J/MNRAS/510/1748 δ Scuti variable stars with OGLE-IV (Netzel+, 2022)
Frequency analysis of δ Scuti stars towards the Galactic bulge.
Netzel H., Pietrukowicz P., Soszynski I., Wrona M.
<Mon. Not. R. Astron. Soc. 510, 1748-1764 (2022)>
=2022MNRAS.510.1748N 2022MNRAS.510.1748N (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Galactic center ; Stars, variable ; Photometry ;
Optical
Keywords: stars: oscillations (including pulsations) -
stars: variable: delta Scuti
Abstract:
We have performed a frequency analysis of 10092 δ Scuti-type
stars detected in the fourth phase of the Optical Gravitational
Lensing Experiment towards the Galactic bulge, which is the most
numerous homogeneous sample of δ Scuti stars observed so far.
The main goal was to search for stars pulsating in at least two radial
modes simultaneously. We have found 3083 candidates for such stars,
which is the largest set obtained to date. Among them, 2655 stars
pulsate in two radial modes, 414 stars pulsate in three radial modes,
and 14 stars pulsate in four radial modes at the same time. We report
the identification of 221 δ Scuti stars pulsating in the
fundamental mode, first overtone, and third overtone simultaneously.
We show the most populated Petersen and Bailey diagrams and discuss
statistical properties of the identified frequencies based on this
numerous sample. Additionally, we present theoretical predictions of
period ratios for δ Scuti stars pulsating in overtones from the
fourth to the seventh.
Description:
In our work, we use the OGLE-IV photometry for over 10000 recently
detected Galactic bulge δ Scuti pulsators (Pietrukowicz et al.
2020AcA....70..241P 2020AcA....70..241P) to perform a frequency search and to select stars
that presumably pulsate in at least two radial modes simultaneously.
As explained in section 2.2 Frequency analysis, from data analysis of
time-series data (about 10092 δ Scuti stars I-band observations,
i.e refer to section 2.1 Time-series data) we apply an automatic
procedure to detect frequency pulsating modes (based on Fourier
analysis as equation 1 shows).
As mentioned, in the analysed sample, 414 stars pulsate in three
radial modes simultaneously. We classified 145 stars as objects
pulsating in the fundamental mode, first, and second overtones
(F+1O+2O), 221 stars as objects pulsating in the fundamental mode,
first, and third overtones (F+1O+3O), and 48 stars as objects
pulsating in the first, second, and third overtones (1O+2O+3O), (refer
to section 3.2 Multimode radial pulsations in δ Scuti stars). We
classify our multimode results in two tables. The table4.dat contains
only 14 candidates for stars pulsating in the fundamental mode, first,
second, and third overtones identified as quadruple-mode δ Scuti
pulsators. The tablea1.dat presents information on triple-mode stars.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 67 14 δ Scuti stars pulsating in four radial
modes simultaneously
tablea1.dat 67 414 δ Scuti stars classified as pulsating in
three radial modes
--------------------------------------------------------------------------------
See also:
J/AcA/71/189 : OGLE Galactic bulge and disk delta Scuti (Soszynski+, 2021)
J/AcA/63/379 : OGLE-III variable stars in Galactic disk area
(Pietrukowicz+, 2013)
J/AcA/52/129 : DIA OGLE2 candidate variable stars catalog (Wozniak+, 2002)
J/AcA/59/239 : VI light curves of LMC long-period variables (Soszynski+, 2009)
J/AcA/64/177 : VI light curves of Galactic Bulge RR Lyrae (Soszynski+, 2014)
http://www.astrouw.edu.pl/ogle/ogle4/OCVS/blg/dsct/ : OGLE online data archive
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- OGLE Star's ID as OGLE-BLG-DSCT-NNNNN (ID) (G1)
21- 31 F11.9 d PF Period of the fundamental fourier
pulsating mode (PF) (G2)
33- 43 F11.9 d P10 Period of the first-overtone fourier
pulsating mode (P1O) (G2)
45- 55 F11.9 d P20 Period of the second-overtone fourier
pulsating mode (P2O) (G2)
57- 67 F11.9 d P30 Period of the third-overtone fourier
pulsating mode (P3O) (G2)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- OGLE Star's ID as OGLE-BLG-DSCT-NNNNN (ID) (G1)
21- 31 F11.9 d PF ? Period of the fundamental fourier
pulsating mode (PF) (G2)
33- 43 F11.9 d P10 ? Period of the first-overtone fourier
pulsating mode (P1O) (G2)
45- 55 F11.9 d P20 ? Period of the second-overtone fourier
pulsating mode (P2O) (G2)
57- 67 F11.9 d P30 ? Period of the third-overtone fourier
pulsating mode (P3O) (G2)
--------------------------------------------------------------------------------
Global notes:
Note (G1): Taken from OGLE Galactic bulge and disk delta Scuti (Soszynski et al.
2021AcA....71..189S 2021AcA....71..189S, Cat. J/AcA/71/189).
Note (G2): The analysis was divided into two steps. The first step was to
determine frequencies present in each star. The second step was to
analyse the obtained frequencies and to select stars with period
ratios falling into known groups of multimode δ Scuti stars.
The procedure fitted the dominant frequency and its harmonics to the
data in the form of Fourier series as shown in the expression 1 of
section 2.2 Frequency analysis.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 14-Nov-2024