J/MNRAS/393/538 Stellar association around gamma Vel (Jeffries+, 2009)
The stellar association around gamma Velorum and its relationship with Vela OB2.
Jeffries R.D., Naylor T., Walter F.M., Pozzo M.P., Devey C.R.
<Mon. Not. R. Astron. Soc., 393, 538-556 (2009)>
=2009MNRAS.393..538J 2009MNRAS.393..538J
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ; X-ray sources
Keywords: stars: formation - stars: pre-main-sequence - stars: Wolf-Rayet -
open clusters and associations: individual: Vela OB2
Abstract:
We present the results of a photometric BVI survey of 0.9deg2 around
the Wolf-Rayet binary gamma2 Vel and its early-type common proper
motion companion gamma1 Vel (together referred to as the gamma Vel
system). Several hundred pre-main-sequence (PMS) stars are identified
and the youth of a subset of these is spectroscopically confirmed by
the presence of lithium in their atmospheres, Halpha emission and high
levels of X-ray activity. We show that the PMS stars are kinematically
coherent and spatially concentrated around gamma Vel. The PMS stars
have similar proper motions to gamma Vel, to main-sequence (MS) stars
around gamma Vel and to early-type stars of the wider Vela OB2
association of which gamma2 Vel is the brightest member.
Description:
A photometric survey of an area around gamma Vel was performed at
the Cerro Tololo Interamerican Observatory (CTIO) 0.9-m telescope.
The survey was done in two parts in different years, but using the
same instrumentation and filters, namely a Tek 2048x2048 CCD with a
13.5x13.5 arcmin2 field of view, the Harris B and V filters and a
Kron-Cousins I filter. The first set of observations, described in
Pozzo et al. (2000MNRAS.313L..23P 2000MNRAS.313L..23P), consisted of eight overlapping
fields surveyed on the night beginning 1999 February 8. The second
set of observations consisted of 20 fields which were surveyed on
the nights beginning 2002 February 8, 10 and 11.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 100 86972 The photometric catalogue for a 0.9deg2 area
around gamma Vel
table3.dat 141 91 Spectroscopy results
table4a.dat 150 136 *X-ray sources from the 2XMM catalogue which are
correlated with 131 unflagged PMS optical
counterparts in our photometric catalogue,
those lying above the locus defined in Fig. 4
table4b.dat 150 124 X-ray sources from the 2XMM catalogue which are
correlated with 124 optical counterparts lying
below the PMS selection locus shown in Fig. 4
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Note on table4a.dat: appended with the details for five sources correlated
with PMS counterparts that have flagged photometry, but which were
included as spectroscopic targets.
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See also:
IX/40 : XMM-Newton 2nd Incremental Source Catalogue (2XMMi) (XMM-SSC, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- [JNW2009] Identification number FF-NNNN
9- 10 I2 h RAh Right ascension (J2000)
12- 13 I2 min RAm Right ascension (J2000)
15- 20 F6.3 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 33 F5.2 arcsec DEs Declination (J2000)
35- 42 F8.3 pix Xpos X position
44- 51 F8.3 pix Ypos Y position
53- 58 F6.3 mag Vmag Johnson V magnitude
60- 64 F5.3 mag e_Vmag rms uncertainty on Vmag
66- 67 A2 --- q_Vmag V band quality flag (G1)
69- 74 F6.3 mag B-V Johnson B-V colour index
76- 80 F5.3 mag e_B-V rms uncertainty on B-V
82- 83 A2 --- q_B-V B-V band quality flag (G1)
85- 90 F6.3 mag V-Ic Johnson-Cousins V-Ic colour index
92- 97 F6.3 mag e_V-Ic rms uncertainty on V-Ic
99-100 A2 --- q_V-Ic V-Ic band quality flag (G1)
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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 I1 --- Night [1/2] Night the spectra were obtained (1)
3- 9 A7 --- [JNW2009] Identification number FF-NNNN
11- 19 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
21- 29 F9.5 deg DEdeg Declination in decimal degrees (J2000)
31- 36 F6.3 mag Vmag Johnson V magnitude
38- 43 F6.4 mag e_Vmag rms uncertainty on Vmag
45- 46 A2 --- q_Vmag Johnson V band quality flag (G1)
48- 52 F5.3 mag B-V Johnson B-V colour index
54- 59 F6.4 mag e_B-V rms uncertainty on B-V
61- 62 A2 --- q_B-V B-V band quality flag (G1)
64- 68 F5.3 mag V-Ic Johnson-Cousins V-Ic colour index
70- 75 F6.4 mag e_V-Ic rms uncertainty on V-Ic
77- 78 A2 --- q_V-Ic V-Ic band quality flag (G1)
80- 82 I3 --- S/N Signal-to-noise ratio per pixel for the
spectrum estimated from the continuum around
the LiI line
84- 89 F6.2 0.1nm EW(Ha) Halpha equivalent width (2)
91- 94 F4.2 0.1nm e_EW(Ha) rms uncertainty on EW(Ha)
96- 99 F4.2 0.1nm EW(Li) Lithium (LiI 6708Å) equivalent width
101-104 F4.2 0.1nm e_EW(Li) rms uncertainty on EW(Li) (3)
106-108 I3 km/s HRV ? Heliocentric radial velocity measured from
the spectrum
110-114 F5.1 mas/yr pmRA ? NOMAD proper motion along RA
116-118 F3.1 mas/yr e_pmRA ? rms uncertainty on pmRA
120-124 F5.1 mas/yr pmDE ? NOMAD proper motion along DE
126-128 F3.1 mas/yr e_pmDE ? rms uncertainty on pmDE
130-133 A4 --- Com Comments on the cross-correlation function
(ccf) used to derive the RV (4)
135-139 F5.2 [solLum] logLX ? X-ray luminosity
141 I1 --- Mm [1/3] Membership flag (5)
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Note (1): Night the spectra were obtained:
1 = 1999 November 24
2 = 1999 November 25
Note (2): a negative value indicates absorption
Note (3): a zero uncertainty indicates that the quoted EW(Li) is a 2σ
upper limit.
Note (4): Comments as follows:
SB2 = double peaked ccf
SB2? = possible double peaked ccf
RR = star is probably a rapid rotator (in excess of ~=30km/s)
E = early-type spectrum
Note (5): Membership flag as follows:
1 = member
2 = non-member
3 = uncertain membership
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Byte-by-byte Description of file: table4a.dat table4b.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [2XMMp]
7- 22 A16 --- 2XMMp 2XMMp designation (JHHMMSS.s+DDMMSS)
24 I1 --- Obs [1/2] Observation number (1)
26- 32 E7.2 --- ML Source detection likelihood
34- 41 E8.3 ct/s pn Count rate in the 0.5-4.5keV range for the
pn instrument (2)
43- 49 E7.3 ct/s e_pn rms uncertainty on pn
51- 58 E8.3 ct/s m1 Count rate in the 0.5-4.5keV range for the
m1 instrument (2)
60- 66 E7.3 ct/s e_m1 rms uncertainty on m1
68- 75 E8.3 ct/s m2 Count rate in the 0.5-4.5keV range for the
m2 instrument (2)
77- 83 E7.3 ct/s e_m2 rms uncertainty on m2
85- 87 F3.1 arcsec Sep Separation between X-ray source and optical
counterpart
89- 95 A7 --- [JNW2009] Identification number FF-NNNN
97-105 F9.5 deg RAdeg Optical source right ascension in
decimal degrees (J2000)
107-115 F9.5 deg DEdeg Optical source declination in
decimal degrees (J2000)
117-122 F6.3 mag Vmag Johnson V magnitude of optical counterpart
124-128 F5.3 mag V-Ic Johnson-Cousins V-Ic colour index of optical
counterpart
130-137 E8.3 mW/m2 Flux Average unabsorbed X-ray flux (0.5-4.5keV)
139-144 F6.3 mag BC Assumed V-band bolometric correction
146-150 F5.2 [-] log(LX/LBol) Derived X-ray to bolometric flux ratio
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Note (1): Observation code:
1 = the observation beginning on MJD 52013
2 = the observation beginning on MJD 52033
Note (2): a zero here indicates the source was not found in that detector.
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Global notes:
Note (G1): Quality flag as follows:
O = O.K.
N = Non-stellar
E = Too close to CCD edge
B = Background fit failed
I = Ill-determined background
P = Position fit failed
S = Saturated
E = Too close to edge
F = Flagged pixel
R = Uncalibrated region
A = Absent input data
M = Negative (minus) counts
V = Variable
C = Large relative transparency correction (cloudy)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Oct-2009