J/MNRAS/493/5565 Multiwavelength view of the open cluster NGC 2527 (Shah+, 2020)
A multiwavelength view of the open cluster NGC 2527: discovery of active stars.
Shah N., Singh K.P., Subramaniam A.
<Mon. Not. R. Astron. Soc., 493, 5565-5582 (2020)>
=2020MNRAS.493.5565S 2020MNRAS.493.5565S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, double and multiple ; Milky Way ;
Positional data ; Stars, distances ; Radial velocities ;
Effective temperatures ; Stars, diameters ; Stars, masses ;
Ultraviolet ; Optical ; X-ray sources
Keywords: stars: activity - (stars:) binaries (including multiple): close -
(Galaxy:) open clusters and associations: individual: NGC 2527 -
ultraviolet: stars - X-rays: binaries - X-rays: stars
Abstract:
Star clusters are ideal platforms for categorizing X-ray emitting
stars and to study X-ray emission as a function of stellar age and
activity. We present a comprehensive study of an open star cluster,
NGC 2527, by combining data from XMM-UVOT-Gaia. Cluster membership of
stars and their photometry are taken from Gaia and cross-matched with
XMM and UVOT detections. We estimate the age of NGC 2527 as ∼630Myr,
reddening as E(B-V)=0.13mag, and a distance of 642±30pc using PARSEC
isochrones. We detect five sub-subgiants and five bandgap stars, which
defy single star evolution. We estimate the temperature, mass, radius,
and luminosity of 53 single stars and 10 potential binary stars using
a python code that fits single and composite Kurucz spectra to
broad-band spectral energy distribution. Among the 12 X-ray emitting
members, we find that five are potential RS CVn-type binaries, two are
potential FK Comae type of red giant branch (RGB) stars, and five are
main sequence (MS) stars with high coronal activity. Members with
strong UV emission comprise one RGB star and several MS stars with UV
excess suggestive of chromospheric activity. Based on comparison with
other clusters, we tentatively suggest that X-ray luminosity of both
RS CVn and contact binaries increases with age, suggesting that more
active binaries are present in older clusters as compared to younger
clusters. This study suggests possible presence of W UMa and FK
Comae-type stars in younger (age∼630Myr) clusters.
Description:
We have analysed data from the XMM-Newton (Jansen et al.
2001A&A...365L...1J 2001A&A...365L...1J) observations (ObsId=0057570101) of NGC 2527
centred on α=08h04m47.20s, δ=-28°07'52.0" performed on
2002 March 18 and 19, during orbit 432. We have analysed only the
deepest XMM-Newton EPIC (PN, MOS1, and MOS2) exposures of NGC 2527.
Several simultaneous short exposure OM (Mason et al.
2001A&A...365L..36M 2001A&A...365L..36M) observations in imaging mode with UVM2 (2310Å)
and UVW2 (2120Å) filters were also used.
We obtained the Swift UVOT photometric data of NGC 2527 from Siegel et
al. (2019AJ....158...35S 2019AJ....158...35S, Cat. J/AJ/158/35). These data had been
processed using the reduction pipeline outlined in Siegel et al.
(2014AJ....148..131S 2014AJ....148..131S).
Gaia DR2 offers a precise and accurate five-parameter astrometric
solution for more than 1.3 billion sources and radial velocities for
more than seven million stars. Cantat-Gaudin et al.
(2018A&A...615A..49C 2018A&A...615A..49C, Cat. J/A+A/615/A49) used precise and accurate
astrometric (proper motion and parallax) measurements from Gaia DR2
catalogue to determine the cluster membership probability of stars for
1229 OCs in the Milky Way. NGC 2527 is part of the Gaia DR2 OC
population in Milky Way Catalogue.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 99 65 Properties of cluster members detected in the
XMM observations
table5.dat 59 55 Fundamental parameters of cluster members
detected in X-ray and UV, estimated from single
Kurucz spectrum SED fitting
table6.dat 101 10 Comparison of fundamental parameters of cluster
members detected in X-ray and UV, estimated from
single and composite Kurucz spectrum SED fitting
tablea.dat 99 62 Magnitudes and fluxes of cluster members that
are detected in XMM OM and Swift UVOT
observations
tableb.dat 110 62 Extinction corrected fluxes obtained from VO
photometry
tablec.dat 106 62 Paranal, 2MASS, and WISE fluxes
tabled.dat 53 10 Properties of peculiar stars that deviate from
standard evolutionary models in the optical CMD
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/158/35 : Swift UVOT Stars Survey. III. Galactic open clusters
(Siegel+, 2019)
J/A+A/615/A49 : TGAS stars membership in 128 open clusters
(Cantat-Gaudin+, 2018)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [1/65] Internal identifier
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 14 F5.2 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 27 F5.2 arcsec DEs Declination (J2000)
29- 33 F5.1 pc Dist Distance
35- 38 F4.1 pc e_Dist Error on Dist
40- 44 F5.2 km/s RV ? Radial velocity
46- 50 F5.2 km/s e_RV ? Error on RV
52- 56 F5.2 mag Gmag Gaia DR2 G magnitude
58- 61 F4.2 mag BP-RP Gaia DR2 BP-RP colour
63- 65 F3.1 --- Pmem Membership probability of the star obtained
from Cantat-Gaudin et al.
(2018A&A...615A..49C 2018A&A...615A..49C, Cat. J/A+A/615/A49)
67 A1 --- l_Rate Limit flag on Rate
69- 74 F6.3 10-3ct/s Rate Count rate
76- 79 F4.2 10-3ct/s e_Rate ? Error on Rate
81 A1 --- l_FX Limit flag on FX
83- 87 F5.2 10-18W/m2 FX X-ray flux
89 A1 --- l_LX Limit flag on LX
91- 95 F5.2 10+22W LX X-ray luminosity
97- 99 A3 --- Type Star type depending upon its position in the
optical CMD (1)
--------------------------------------------------------------------------------
Note (1): Type as follows:
B = Binary (13/65)
MS = Main sequence (41/65)
PB = Potential binary (7/65)
RGB = Red giant branch (3/65)
SSG = Sub-giant (1/65)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [1/65] Internal identifier
4- 7 I4 K Teff Effective temperature
9- 11 I3 K e_Teff Error on Teff
13- 15 F3.1 [cm/s2] logg Surface gravity
17- 19 F3.1 [cm/s2] e_logg Error on logg
21- 25 F5.2 Rsun Rad Star radius
27- 30 F4.2 Rsun e_Rad Error on Rad
32- 36 F5.2 Lsun L Star luminosity
38- 42 F5.2 Lsun e_L Error on L
44- 47 F4.2 Msun Mass Star mass
49- 55 F7.2 --- chi2 Reduced chi-squared of the best-fitting
Kurucz spectrum
57 A1 --- Excess [YN] Indicates whether an Excess feature is
observed in the residual plots of the single
spectrum SED fit
59 A1 --- Dip [YN] Indicates whether a Dip feature is
observed in the residual plots of the single
spectrum SED fit
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [8/61] Internal identifier
4- 7 I4 K T Effective temperature from the best-fitting
single Kurucz spectrum
9- 11 I3 K e_T Error on T
13- 17 F5.1 --- chi2 Reduced chi-squared of the best-fitting single
Kurucz spectrum
19- 23 I5 K T1 Effective temperature of the first component in
the Kurucz and Kurucz composite spectrum fit
25- 28 I4 K e_T1 Error on T1
30- 34 I5 K T2 Effective temperature of the second component
in the Kurucz and Kurucz composite spectrum fit
36- 39 I4 K e_T2 Error on T2
41- 45 F5.1 --- chi2KK Reduced chi-squared of the best-fitting
composite spectrum
47- 51 F5.2 Rsun R1 Radius of the first component in the Kurucz and
Kurucz composite spectrum fit
53- 56 F4.2 Rsun e_R1 Error on R1
58- 62 F5.2 Rsun R2 Radius of the second component in the Kurucz
and Kurucz composite spectrum fit
64- 67 F4.2 Rsun e_R2 Error on R2
69- 73 F5.2 Lsun L1 Luminosity of the first component in the Kurucz
and Kurucz composite spectrum fit
75- 79 F5.2 Lsun e_L1 Error on L1
81- 85 F5.2 Lsun L2 Luminosity of the second component in the
Kurucz and Kurucz composite spectrum fit
87- 91 F5.2 Lsun e_L2 Error on L2
93- 96 F4.2 Msun M1 ? Mass of the first component in the Kurucz and
Kurucz composite spectrum fit
98- 101 F4.2 Msun M2 ? Mass of the second component in the Kurucz
and Kurucz composite spectrum fit
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [1/62] Internal identifier
4- 8 F5.2 mag UVW2mag ? Swift/UVOT UVW2-band magnitude
10- 13 F4.2 mag e_UVW2mag ? Error on UVW2mag
15- 19 F5.2 mag UVM2mag ? Swift/UVOT UVM2-band magnitude
21- 24 F4.2 mag e_UVM2mag ? Error on UVM2mag
26- 30 F5.2 mag UVW1mag ? Swift/UVOT UVW1-band magnitude
32- 35 F4.2 mag e_UVW1mag ? Error on UVW1mag
37- 41 F5.2 10-16W/m2/nm FUVW2S ? Swift/UVOT UVW2 flux
43- 46 F4.2 10-16W/m2/nm e_FUVW2S ? Error on FUVW2S
48- 52 F5.2 10-16W/m2/nm FUVM2S ? Swift/UVOT UVM2 flux
54- 57 F4.2 10-16W/m2/nm e_FUVM2S ? Error on FUVM2S
59- 63 F5.2 10-16W/m2/nm FUVW1S ? Swift/UVOT UVW1 flux
65- 68 F4.2 10-16W/m2/nm e_FUVW1S ? Error on FUVW1S
70- 75 F6.2 10-16W/m2/nm FUVW2X ? XMM/OM UVW2 flux
77- 80 F4.2 10-16W/m2/nm e_FUVW2X ? Error on FUVW2X
82- 86 F5.2 10-16W/m2/nm FUVM2X ? XMM/OM UVM2 flux
88- 91 F4.2 10-16W/m2/nm e_FUVM2X ? Error on FUVM2X
93- 95 I3 --- QFUVW2 ? Quality flag in the OM UVW2 filter
97- 99 I3 --- QFUVM2 ? Quality flag in the OM UVM2 filter
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [1/62] Internal identifier
4- 9 F6.2 10-16W/m2/nm FB ? Flux on the APASS B-band
11- 15 F5.2 10-16W/m2/nm e_FB ? Error on FB
17- 21 F5.2 10-16W/m2/nm FV ? Flux on the APASS V-band
23- 26 F4.2 10-16W/m2/nm e_FV ? Error on FV
28- 32 F5.2 10-16W/m2/nm Fg ? Flux on the Pan-STARRS g-band
34- 37 F4.2 10-16W/m2/nm e_Fg ? Error on Fg
39- 42 F4.2 10-16W/m2/nm Fr ? Flux on the Pan-STARRS r-band
44- 47 F4.2 10-16W/m2/nm e_Fr ? Error on Fr
49- 52 F4.2 10-16W/m2/nm Fz ? Flux on the Pan-STARRS z-band
54- 57 F4.2 10-16W/m2/nm e_Fz ? Error on Fz
59- 62 F4.2 10-16W/m2/nm Fy ? Flux on the Pan-STARRS y-band
64- 67 F4.2 10-16W/m2/nm e_Fy ? Error on Fy
69- 72 F4.2 10-16W/m2/nm Fi ? Flux on the Pan-STARRS i-band
74- 77 F4.2 10-16W/m2/nm e_Fi ? Error on Fi
79- 83 F5.2 10-16W/m2/nm FBP Flux on the Gaia BP-band
85- 88 F4.2 10-16W/m2/nm e_FBP Error on FBP
90- 94 F5.2 10-16W/m2/nm FG Flux on the Gaia G-band
96- 99 F4.2 10-16W/m2/nm e_FG Error on Fg
101-105 F5.2 10-16W/m2/nm FRP Flux on the Gaia RP-band
107-110 F4.2 10-16W/m2/nm e_FRP Error on FRP
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- SXOM [1/62] Internal identifier
4- 8 F5.2 10-16W/m2/nm Fu ? Flux on the Paranal/OmegaCAM u-band
10- 13 F4.2 10-16W/m2/nm e_Fu ? Error on Fu
15- 19 F5.2 10-16W/m2/nm FHalpha ? Flux on the Paranal/OmegaCAM
Hα-band
21- 24 F4.2 10-16W/m2/nm e_FHalpha ? Error on FHalpha
26- 29 F4.2 10-16W/m2/nm Fg ? Flux on the Paranal/OmegaCAM g-band
31- 34 F4.2 10-16W/m2/nm e_Fg ? Error on Fg
36- 39 F4.2 10-16W/m2/nm Fr ? Flux on the Paranal/OmegaCAM r-band
41- 44 F4.2 10-16W/m2/nm e_Fr ? Error on Fr
46- 49 F4.2 10-16W/m2/nm Fi ? Flux on the Paranal/OmegaCAM i-band
51- 54 F4.2 10-16W/m2/nm e_Fi ? Error on Fi
56- 60 F5.2 10-17W/m2/nm FJ Flux on the 2MASS J-band
62- 65 F4.2 10-17W/m2/nm e_FJ Error on FJ
67- 71 F5.2 10-17W/m2/nm FH Flux on the 2MASS H-band
73- 76 F4.2 10-17W/m2/nm e_FH Error on FH
78- 81 F4.2 10-17W/m2/nm FKs Flux on the 2MASS Ks-band
83- 86 F4.2 10-17W/m2/nm e_FKs Error on FKs
88- 91 F4.2 10-19W/m2/nm FW1 Flux on the WISE W1-band
93- 96 F4.2 10-19W/m2/nm e_FW1 Error on FW1
98- 101 F4.2 10-19W/m2/nm FW2 Flux on the WISE W2-band
103- 106 F4.2 10-19W/m2/nm e_FW2 Error on FW2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tabled.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (ICRS) at Ep=2015.5
4- 5 I2 min RAm Right ascension (ICRS) at Ep=2015.5
7- 8 I2 s RAs Right ascension (ICRS) at Ep=2015.5
10 A1 --- DE- Declination sign (ICRS) at Ep=2015.5
11- 12 I2 deg DEd Declination (ICRS) at Ep=2015.5
14- 15 I2 arcmin DEm Declination (ICRS) at Ep=2015.5
17- 18 I2 arcsec DEs Declination (ICRS) at Ep=2015.5
20- 24 F5.1 pc Dist Distance from Gaia DR2
26- 29 F4.1 pc e_Dist Error on Dist
31- 35 F5.2 mag Gmag Gaia DR2 G-band magnitude
37- 40 F4.2 mag BP-RP Gaia DR2 BP-RP colour
42- 43 I2 km/s RV ? Radial velocity from Gaia DR2
45 I1 km/s e_RV ? Error on RV
47- 49 F3.1 --- Pmem Membership probability of the star
51- 53 A3 --- Type Star type depending upon its position in the
optical CMD (1)
--------------------------------------------------------------------------------
Note (1): Type as follows:
SSG = Sub-subgiant (4/10)
Gap = Gap star (5/10)
RS = Red Straggler (1/10)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 12-May-2023