J/A+A/589/A70 Gamma Vel cluster membership and IMF (Prisinzano+, 2016)
The Gaia-ESO Survey:
membership and Initial Mass Function of the Gamma Velorum cluster.
Prisinzano L., Damiani F., Micela G., Jeffries R.D., Franciosini E.,
Sacco G.G., Frasca A., Klutsch A., Lanzafame A., Alfaro E.J., Biazzo K.,
Bonito R., Bragaglia A., Caramazza M., Vallenari A., Carraro G.,
Costado M.T., Flaccomio E., Jofre P., Lardo C., Monaco L., Morbidelli L.,
Mowlavi N., Pancino E., Randich S., Zaggia S.
<Astron. Astrophys. 589, A70 (2016)>
=2016A&A...589A..70P 2016A&A...589A..70P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open - Stars, pre-main sequence - Stars, masses -
Radial velocities - HR diagrams - Spectroscopy
Keywords: stars: pre-main sequence -
open clusters and associations: individual: Gamma Velorum -
stars: formation - stars: luminosity function, mass function -
techniques: radial velocities - techniques: spectroscopic
Abstract:
Understanding the properties of young open clusters, such as the
Initial Mass Function (IMF), star formation history and dynamic
evolution, is crucial to obtain reliable theoretical predictions of
the mechanisms involved in the star formation process. We want to
obtain a list, as complete as possible, of confirmed members of the
young open cluster Gamma Velorum, with the aim of deriving general
cluster properties such as the IMF. We used all available
spectroscopic membership indicators within the Gaia-ESO public archive
together with literature photometry and X-ray data and, for each
method, we derived the most complete list of candidate cluster
members. Then, we considered photometry, gravity and radial velocities
as necessary conditions to select a subsample of candidates whose
membership was confirmed by using the lithium and Hα lines and
X-rays as youth indicators. We found 242 confirmed and 4 possible
cluster members for which we derived masses using very recent stellar
evolutionary models. The cluster IMF in the mass range investigated in
this study shows a slope of α=2.6±0.5 for 0.5<M/M_☉<1.3
and α=1.1±0.4 for 0.16<M/M☉<0.5 and is consistent with a
standard IMF. The similarity of the IMF of the young population around
gamma2 Vel to that in other star forming regions and the field
suggests it may have formed through very similar processes.
Description:
We derived a list as complete as possible of confirmed members of the
young open cluster Gamma Velorum, with the aim of deriving general
cluster properties such as the IMF. We used all available
spectroscopic membership indicators within the Gaia-ESO public
archive, based on spectra acquired with FLAMES a the VLT using the
GIRAFFE intermediate-resolution spectrograph. In addition, we used
literature photometry and X-ray data. For each membership criterion,
we derived the most complete list of candidate cluster members. Then,
we considered photometry, gravity, and radial velocities as necessary
conditions for selecting a subsample of candidates whose membership
was confirmed by using the lithium and Halpha lines and X-rays as
youth indicators. Table 5 lists the fundamental parameters of the
confirmed and possible members in Gamma Velorum, i.e. photometry,
radial velocities, equivalent widths of the lithium line, the Halpha
activity index, the X-ray flag, the gravity gamma index and the
stellar masses. Finally the binarity and membership flags are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 96 246 Fundamental stellar parameters for cluster members
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See also:
J/MNRAS/393/538 : Stellar association around gamma Vel (Jeffries+, 2009)
J/A+A/563/A94 : Kinematics of the Gamma Vel cluster (Jeffries+, 2014)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- CName Target Name in the Gaia-ESO archive
(HHMMSSss+DDMMSSs)
18- 22 F5.2 mag Vmag Apparent V magnitude (Johnson)
24- 27 F4.2 mag V-Ic V-I color index (Cousins)
29- 33 F5.2 km/s HRV Mean heliocentric radial velocities
35- 39 F5.2 km/s e_HRV rms uncertainty on HRV
41- 46 F6.2 0.1nm EWLi ? Equivalent width of 6708Å Li line
48- 53 F6.2 0.1nm e_EWLi ? rms uncertainty on EWLi
55- 59 F5.3 --- alphac ? alphac chromospheric activity index
61- 65 F5.3 --- e_alphac ? rms uncertainty on alphac
67 I1 --- fXrays [0/1]? X-rays detection flag (1=yes)
69- 73 F5.3 --- gamma ? Gravity index gamma
75- 79 F5.3 --- e_gamma ? rms uncertainty on gamma
81- 85 F5.3 Msun Mass ? Stellar Mass
87- 91 F5.3 Msun e_Mass ? rms uncertainty on Mass
93 I1 --- fBin [0/2] Binarity flag (1)
95- 96 A2 --- fMem [CM PM] Membership flag (2)
-------------------------------------------------------------------------------
Note (1): Binarity flag as follows:
0 = single star
1 = single-lined spectroscopic binary (SB1)
2 = double-lined spectroscopic binary (SB2)
Note (2): Membership flag as follows:
CM = confirmed cluster members
PM = possible cluster members
-------------------------------------------------------------------------------
Acknowledgements:
Loredana Prisinzano, loredana(at)astropa.inaf.it
References:
Jeffries et al., 2009MNRAS.393..538J 2009MNRAS.393..538J, Cat. J/MNRAS/393/538
The stellar association around Gamma Velorum and its relationship with Vela OB2
Jeffries et al. 2014A&A...563A..94J 2014A&A...563A..94J, Cat. J/A+A/563/A94
The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum cluster
(End) Loredana Prisinzano [INAF, Italy], Patricia Vannier [CDS] 20-Apr-2016