J/AJ/155/137 RRLs in globulars. V.ω Centauri NIR photometry (Braga+, 2018)
On the RR Lyrae stars in globulars.
V. The complete near-infrared (JHKs) census of ω Centauri RR Lyrae
variables.
Braga V.F., Stetson P.B., Bono G., Dall'Ora M., Ferraro I., Fiorentino G.,
Iannicola G., Marconi M., Marengo M., Monson A.J., Neeley J., Persson S.E.,
Beaton R.L., Buonanno R., Calamida A., Castellani M., Di Carlo E.,
Fabrizio M., Freedman W.L., Inno L., Madore B.F., Magurno D., Marchetti E.,
Marinoni S., Marrese P., Matsunaga N., Minniti D., Monelli M., Nonino M.,
Piersimoni A.M., Pietrinferni A., Prada-Moroni P., Pulone L.,
Stellingwerf R., Tognelli E., Walker A.R., Valenti E., Zoccali M.
<Astron. J., 155, 137 (2018)>
=2018AJ....155..137B 2018AJ....155..137B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, infrared ;
Photometry, UBVRI
Keywords: globular clusters: individual (ω Centauri) -
stars: distances - stars : horizontal-branch -
stars: variables: RR Lyrae
Abstract:
We present a new complete near-infrared (NIR, JHKs) census of RR Lyrae
stars (RRLs) in the globular ω Cen (NGC 5139). We collected
15472 JHKs images with 4-8 m class telescopes over 15 years (2000-2015)
covering a sky area around the cluster center of 60x34 arcmin2.
These images provided calibrated photometry for 182 out of the 198 cluster
RRL candidates with 10 to 60 measurements per band. We also provide
new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H)
and 174 (Ks) RRLs. These data were supplemented with single-epoch JKs
magnitudes from VHS (Mcmahon et al. 2013Msngr.154...35M 2013Msngr.154...35M) and with
single-epoch H magnitudes from 2MASS (Cat. VII/233). Using proprietary
optical and NIR data together with new optical light curves (ASAS-SN)
we also updated pulsation periods for 59 candidate RRLs. As a whole,
we provide JHKs magnitudes for 90 RRab (fundamentals), 103 RRc
(first overtones) and one RRd (mixed-mode pulsator). We found that
NIR/optical photometric amplitude ratios increase when moving from first
overtone to fundamental and to long-period (P>0.7 days) fundamental RRLs.
Using predicted period-luminosity-metallicity relations, we derive a true
distance modulus of 13.674±0.008±0.038 mag (statistical error and
standard deviation of the median) based on spectroscopic iron abundances,
and of 13.698±0.004±0.048 mag based on photometric iron abundances.
We also found evidence of possible systematics at the 5%-10% level in
the zero-point of the period-luminosity relations based on the five
calibrating RRLs whose parallaxes had been determined with the HST.
Description:
The grand total of our images is 15472: 5102 in J, 4872 in H and 5498
in Ks, collected over 15 years (2000 January-2015 January).
The majority (∼95%) of our data were collected with the FourStar imager
(pixel scale: 0.16 arcsec/pix) at the 6.5 m Magellan-Baade telescope
at Las Campanas during five nights in 2013 June (10800 images, Figure 1)
and three nights in 2015 January (3979 images, Figure 2; one exposure
was missing the data from chip 3). Around 5% of our images were collected
with the NEWFIRM instrument (0.4 arcsec/pix) at the CTIO 4.0 m telescope
during one night in 2010 May (308 images) and with the SOFI camera
(0.25 arcsec/pix) at the NTT 3.6 m telescope at La Silla (314 images)
during 2000-2005. Finally, we also collected 70 images with MAD at VLT
8.0 m, during 2007 April 3-5 and 2007 June 1 and 3.
Objects:
---------------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------------
13 26 47.28 -47 28 46.1 ω Centauri = NGC 5139
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 134 198 NIR-JHKs-mean magnitudes and amplitudes for
ω Cen RRLs
table3.dat 38 19 New optical mean magnitudes and amplitudes of
RRL candidates in ω Cen
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
V/150 : Updated catalog of variable stars in globular clusters
(Clement+ 2017)
J/A+AS/105/145 : RR Lyr stars of ome Cen (Petersen 1994)
J/A+AS/125/343 : OGLE RR Lyr stars in omega Cen (Kaluzny+ 1997)
J/AJ/119/1824 : Caby photometry of Ω Centauri (Rey+, 2000)
J/A+A/424/1101 : Variable Stars in the field of ω Cen (Kaluzny+, 2004)
J/ApJ/640/L43 : Metallicities of RR Lyrae stars in Omega Cen (Sollima+, 2006)
J/AJ/133/1447 : Light curves of variable stars in ω Cen
(Weldrake+, 2007)
J/PASP/126/521 : UBVRIJHK photometry of RR Lyrae in M4 (Stetson+, 2014)
J/A+A/574/A15 : RR Lyrae in omega Cen (Fernandez-Trincado+, 2015)
J/ApJ/808/11 : RR Lyrae stars in M4. II. Spitzer/IRAC phot. (Neeley+, 2015)
J/AJ/152/170 : RRLs in globulars. IV. UBVRI photometry in Omega Cen
(Braga+, 2016)
J/A+A/604/A120 : omega Cen RR Lyrae and SX Phoenicis stars (Navarrete+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- ID Star identifier (VNNN or NVNNN)
7- 8 A2 --- f_ID [Bl g] Flag on ID (1)
10- 19 F10.8 d Pnew [0.253934/1.012155]? New period
21- 21 A1 --- f_Pnew [cde] Flag on Pnew (2)
23- 33 F11.8 d Pold [0.28166279/0.9325]? Old period (3)
35- 35 A1 --- f_Pold [f] Flag on Pold (4)
37- 48 A12 --- Var Variable type
50 A1 --- f_Var [h] Flag on Var (5)
52- 53 A2 --- f_Jmag Flag on Jmag (6)
55- 60 F6.3 mag Jmag [11.401/17.003] Apparent J band magnitude
62- 66 F5.3 mag e_Jmag [0.002/0.21] Uncertainty in Jmag
68- 72 F5.3 mag AJ [0.026/0.623]? Amplitude in J band (7)
74- 78 F5.3 mag e_AJ [0.005/0.082]? Uncertainty in AJ (7)
80- 81 A2 --- f_Hmag Flag on Hmag (6)
83- 88 F6.3 mag Hmag [10.812/16.692]? Apparent H band magnitude
90- 94 F5.3 mag e_Hmag [0.003/0.16]? Uncertainty in Hmag
96-100 F5.3 mag AH [0.018/0.461]? Amplitude in H band (7)
102-106 F5.3 mag e_AH [0.006/0.081]? Uncertainty in AH (7)
108-109 A2 --- f_Ksmag Flag on Ksmag (6)
111-116 F6.3 mag Ksmag [10.81/16.623] Apparent Ks band magnitude
118-122 F5.3 mag e_Ksmag [0.003/0.16] Uncertainty in Ksmag
124-128 F5.3 mag AKs [0.013/0.394]? Amplitude in Ks band (7)
130-134 F5.3 mag e_AKs [0.005/0.038]? Uncertainty in AKs (7)
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Note (1): Flag as follows:
Bl = Variable affected by Blazhko modulation;
g = Non-member RRL candidate.
Note (2): Flag as follows:
c = The new period estimate is more accurate than the period in Braga et al.
(2016, J/AJ/152/170);
d = The new period estimate suggests a period variation in respect to
Braga et al. (2016, J/AJ/152/170);
e = Period from analysis of ASAS-SN optical data.
Note (3): Only old periods that were updated in this work.
Note (4): Flag as follows:
f = Period from Clement et al. (2001, Cat. V/150) and references therein.
Note (5): Flag as follows:
h = Updated variable type.
Note (6): Method or source used to derive the mean magnitude and/or amplitude,
defined as follows:
S = Spline fit;
P = PLOESS fit;
T = Template fit;
m = Median over the phase points;
M = Median magnitude over MAD photometry;
V = VHS (Mcmahon et al. 2013Msngr.154...35M 2013Msngr.154...35M) single phase-point photometry;
2M = 2MASS (Cat. VII/233) single phase-point photometry;
N = No photometric data available for this variable;
* = Measures probably affected by blending or close bright stars. They are
removed as outliers in the period-luminosity (PL) relations.
Note (7): The photometric amplitudes were only estimated for the RRLs for which
the fit of the light curves was performed either with the S (Spline fit) or
the P (PLOESS fit) method. We do not provide photometric amplitudes for the
variables V59 and V106, since the optical amplitudes and the ratio between
optical and NIR amplitudes are input parameters. Note that the uncertainty on
the JHKs mean magnitudes from 2MASS and VHS data, was estimated as the
expected JHKs semi-amplitudes of these variables. In particular, we adopted
the V-band amplitude from ASAS-SN and the optical/NIR amplitude ratios derived
in Section 4.2. We decided to adopt this approach for a very conservative
estimate of the photometric error on single phase points. Note that we
estimated the amplitudes only with the S and P method, that is, when a fit of
the light curve is available, with the exception of the template fit for which
the amplitude is an input.
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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- 5 A5 --- ID Star identifier (VNNN or NVNNN)
7 A1 --- n_ID [abc] Note on ID (1)
9 A1 --- Band [UBVRI] Observed band
11- 16 F6.3 mag magmean ? Mean magnitude in Band (2)
18- 22 F5.3 mag e_magmean ? Uncertainty in magmean (2)
24 A1 --- n_magmean [b] Note on magmean (b=blended source)
26- 30 F5.3 mag Amp ? Amplitude in Band (2)
32- 36 F5.3 mag e_Amp ? Uncertainty in Amp (2)
38 A1 --- n_Amp [b] Note on Amp (b=blended source)
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Note (1): Note as follows:
a = From ASAS-SN optical data;
b = The ASAS-SN optical light curve is heavily affected by blending, see notes
in the individual variables appendix;
c = From our own optical data.
Note (2): All mean magnitudes and amplitudes were derived from spline fits.
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History:
From electronic version of the journal
References:
Braga et al. Paper I. 2015ApJ...799..165B 2015ApJ...799..165B
Neeley et al. Paper II. 2015ApJ...808...11N 2015ApJ...808...11N, Cat. J/ApJ/808/11
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
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 12-Nov-2018