J/MNRAS/468/870 RR Lyrae variables in M33 (Tanakul+, 2017)
RR Lyrae variables in M33:
two new fields and an analysis of the galaxy's population.
Tanakul N., Yang S.-C., Sarajedini A.
<Mon. Not. R. Astron. Soc., 468, 870-884 (2017)>
=2017MNRAS.468..870T 2017MNRAS.468..870T (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry, VRI
Keywords: stars: variables: RR Lyrae - galaxies: individual: M33 - Local Group
Abstract:
We present a re-analysis of M33 RR Lyrae variables in four different
fields: two inner disc fields and two outer disc fields. These are
located at 8.5, 8.7, 36 and 46 arcmin from the centre of M33,
respectively. We identify 48 new RR Lyrae variable stars and refine
the light-curve properties of 51 previously identified variables. From
the light curves, we calculate reddenings and metallicities for each
star. Using data in this paper and previously published material, we
are able to construct a radial density profile for the RR Lyrae stars
in M33. This profile, when plotted in log space, has a slope of
~-2.0±0.15 which agrees with the radial distribution of halo stars
in the Milky Way and M31. This suggests that the majority of M33 RR
Lyrae variables observed so far belong to the halo. We also examine
the RR Lyrae specific frequency and absolute magnitude relation in M33
and find good agreement with previous studies.
Description:
The data in this study were taken using the Advanced Camera for
Surveys (ACS) onboard HST as part of two different programmes.
The outer disc field observations were made in 2004 June and August as
part of the GO-9837 program (PI: Ferguson). In this region, there are
two fields, which we designate F1 and F2, as shown in Fig. 1 and the
observing log in Table 2. The two fields were observed in the F606W
and F814W filters for a total of 8 and 16 epochs, respectively.
The images in the inner disc fields were taken as part of the program
GO-9873 (PI: Sarajedini). Two fields were observed in this region, the
M9 cluster field and U49 cluster field (see Fig. 1). The details of
the observations are described fully in Sarajedini et al. (2006) and
summarized in Table 2. These cluster fields are also observed in the
F606W and F814W filters with 8 and 16 epochs in each filter,
respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table11.dat 87 99 RRL properties
table3.dat 42 96 Time-series photometry of variable stars in
F1 field
table4.dat 42 1416 Time-series photometry of M9 RRLs
table5.dat 42 864 Time-series photometry of U49 RRLs
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See also:
J/AJ/132/1361 : RR Lyrae variables in M33 (Sarajedini+, 2006)
J/ApJ/724/799 : RR Lyrae variables in M33. II. (Yang+, 2010)
Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Field [ F1 M9 U49] Field name
5- 8 A4 --- Inst [WFC1 WFC2] Instrument
10- 16 A7 --- Name Star name, VNNNNNN
18 I1 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 27 F5.2 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 40 F5.2 arcsec DEs Declination (J2000)
42- 47 F6.3 mag <Vmag> Mean V magnitude
49- 54 F6.3 mag <Imag> Mean I magnitude
56- 60 F5.3 mag <V-I> Mean V-I colour index
62- 66 F5.3 d Per Period
68- 72 F5.3 d e_Per rms uncertainty on Per
74- 78 F5.3 mag IAmp Amplitude of variation in I band
80- 84 F5.3 mag e_IAmp rms uncertainty on IAmp
86- 87 A2 --- Type RR Lyrae type
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Byte-by-byte Description of file: table3.dat table4.dat table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Field [F1 M9 U49] Field name
5- 8 A4 --- Inst [WFC1 WFC2] Instrument
10 A1 --- Filt [VI] Filter
12- 21 F10.5 d HJD Epoch (HJD-2450000)
23- 28 F6.3 mag mag Magnitude in filter
30- 34 F5.3 mag e_mag rms uncertainty in mag
36- 42 A7 --- Name Star name, VNNNNNN
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Dec-2019