J/A+A/581/A39 MWSC IV. 63 new open clusters (Scholz+, 2015)
Global survey of star clusters in the Milky Way.
IV. 63 new open clusters detected by proper motions.
Scholz R.-D., Kharchenko N.V., Piskunov A.E., Roeser S., Schilbach E.
<Astron. Astrophys. 581, A39 (2015)>
=2015A&A...581A..39S 2015A&A...581A..39S
ADC_Keywords: Clusters, open ; Proper motions
Keywords: catalogs - surveys - proper motions - globular clusters: general -
open clusters and associations: general - Galaxy: stellar content
Abstract:
We present a list of 63 new open clusters that were found in the frame
of the project Milky Way Star Clusters (MWSC). The target list was
compiled as density enhancements using coordinates and proper motions
from the 2MAst and UCAC4 catalogues. For confirmed clusters we
determined a homogeneous set of astrophysical parameters such as
membership, angular radii of the main morphological parts, proper
motion, distance, reddening, age, tidal parameters, all based on 2MAst
data.
Description:
We first selected high-quality samples from the 2MAst and UCAC4
catalogues for comparison and verification of the proper motions. For
441 circular proper motion bins (radius 15mas/yr) within±50mas/yr,
the sky outside a thin Galactic plane zone (|b|<5°) was binned in
small areas ('sky pixels') of 0.25x0.25°2, Sky pixels with
enhanced numbers of stars with a certain common proper motion in both
catalogues were considered as cluster candidates. In total we
discovered 692 density enhancements (regarded as cluster candidates).
These candidates were cross-identified with known objects.
Unidentified objects were passed through the standard MWSC pipeline
(described in Kharchenko et al., 2012, Cat. J/A+A/543/A156) for
verification, cluster membership construction and structure, kinematic
and astrophysical parameter determination. The basic stellar data were
taken from the all-sky catalogue 2MAst (2MASS with Astrometry), that
was extracted from the all-sky catalogues PPMXL (Roeser et al. 2010,
Cat.I/317) and 2MASS (Cutri et al. 2003, Cat.II/246). We found
that 355 candidates coincide or overlap with known objects. From the
remaining candidates, 270 could not be confirmed by the MWSC pipeline,
whereas 63 were classified as real star clusters, for which we
determined their basic cluster parameters.
Around each confirmed object from our target list we defined a
circular area with a radius of ra=r2+radd where r2 is an initial
estimate of the cluster radius, and radd=0.3deg. In these areas we
selected in 2MAst only those stars with flags Rflg (the 2nd triple of
the flags in 2MASS) set to 1, 2, or 3 in each band, i.e. the stars
with the best quality detections in photometric and astrometric data.
The 63 sky areas with confirmed clusters contain about 0.49 mln 2MAst
stars with best quality detections in photometric and astrometric
data. We selected most probable members and determined - with a
homogeneous method/pipeline - angular sizes of the main morphological
parts, heliocentric distances, colour-excesses, mean proper motions,
ages, tidal parameters.
This work represents the second extension of the MWSC survey
(Kharchenko et al. 2012, Cat. J/A+A/543/A156, 2013, Cat. J/A+A/558/A53),
which had an original input list of 3784 targets. After the first
extension by Schmeja et al. (2014, Cat. J/A+A/568/A51), who
investigated 782 further candidates, we analysed 692 new candidates.
We have adopted for them MWSC numbers starting with 4001.
We present:
The Catalogue of 63 new MWSC open clusters, which includes several
files: Catalogue of cluster parameters (confirmed clusters only);
Index of all 692 candidates; Notes for every item of the index list.
Within each list the entries are ordered by the MWSC number.
The Catalogues of the MWSC Stars in 63 circular sky areas with
confirmed clusters. Files are ordered by MWSC number; inside each sky
area the entries are ordered by Ks magnitudes.
The Atlas of 63 new MWSC clusters diagrams. In the Atlas the Cluster
pages are ordered by MWSC number.
All the data are given in the same format as in the main MWSC catalogue
(J/A+A/558/A53).
Description of file: atlas/*
For each cluster we prepared two EPS-pages of diagrams:
Page 1 contains the cluster map as the basic panel
(file MWSCNamemap.eps.gz),
Page 2 contains the Ks,(J-Ks) and Ks,(J-H) CMDs as basic panels
(file MWSCNamecmd.eps.gz).
The legend on each page gives the cluster name, MWSC number, (COCD number);
equatorial RAJ2000, DecJ2000, and galactic l, b coordinates of the cluster
centre; apparent cluster sizes r0, r1, r2, [number of 1σ-members within
the corresponding radius]; weighted average components PM(X,Y) of proper
motion with their rms errors, [number of stars used to compute the average];
the average radial velocity, RV with their rms error, [the number of stars
used to compute the average]; distance to the cluster, d, distance modulus,
(Ks-MKs); NIR colour-excesses, E(J-H), E(J-Ks), interstellar extinction,
A(Ks); cluster age, its rms error, [the number of stars used to compute the
average age, or it is -1 if a manual isochrone fit was applied].
Additionally we show in the 2nd pages: an empirical correction
ΔH for a better isochrone fit in the Ks,(J-H) diagram.
Symbols and their colours have the same meaning in all plots. Stars are
shown as coloured circles or dots. Cyan symbols mark stars outside the
cluster radius r2, green symbols are stars within r2. The most probable
kinematic and photometric members (1σ-members) are indicated in black,
red, or blue. Black is for members located within r1 (a visible radius of
the central part), red for members between r1 and r2, and blue for stars
outside r2 (the probabilities are formal). Cyan bars show the uncertainty
for 1σ-members.
Description of files MWSCNamemap.eps.gz (Page 1):
Page 1 contains five diagrams with spatial information.
The right panel is a map of the cluster neighborhood (MAP),
the left panels show (upside-down) relations depending on the distance from
the cluster centre, r, for:
- magnitude Ks (Ks vs. r),
- proper motions (PM vs. r),
- density profile diagram (DPD).
MAP:
Stars are displayed as small circles.
The circle size corresponds to the stellar magnitude ranged in six Ks mag
intervals: < 6.0, 6.0 - 8.0, 8.0 - 10.0, 10.0 - 12.0, 12.0 - 14.0, > 14.0.
Blue cross : cluster centre selected in this study;
Blue plus : cluster centre from the literature;
Magenta plusses : centres of other clusters (from target list)
visible (if any) in the map;
Dotted blue large circle : cluster core border (r0);
Solid blue large circle : inner cluster border (r1);
Dashed blue large circle : cluster corona border (r2).
The left panels:
Blue vertical dotted, solid, dashed lines mark r0, r1, r2, respectively.
PM vs. r: Magenta horizontal lines correspond to the average proper
motion of the cluster determined in this paper;
DPD: Density profiles (Log of Number of stars per 1 sq.deg) are shown for
all stars (green line), 3σ-members (blue line), 2σ-members
(magenta line) and 1σ-members (black line).
Description of files MWSCNamecmd.eps.gz (Page 2):
Page 2 contains diagrams with kinematic and photometric information.
The three left panels are:
- two PM_(X,Y) vs. Ks relations, i.e. PM-magnitude equation diagrams (MEDs);
- the vector point diagram of proper motions (VPD).
The two upper right panels are:
- relations (Ks,(J-H) and Ks,(J-Ks), i.e. the colour-magnitude diagrams
(CMDs).
The bottom right panels:
- colour-colour diagrams (CCDs);
- reddening-independent parameter Q-colour diagrams (QCDs).
The CCDs and QCDs are separated into two subpanels (as well as CMDs and
MEDs are separated into two parts via a broken line). The division is
made with respect to the Ksmc magnitude: in the bottom subpanels we
place data for Ks>Ks_mc, in the upper ones - for Ks<Ksmc, where
Ksmc is Ks-magnitude at the bluest colour (J-Ks) of the isochrone
closest to the determined cluster age.
CMDs:
Magenta curve: the apparent isochrone closest to the determined cluster age;
Solid blue lines: left and right borders of a domain of 100% photometric
cluster members;
Solid red lines: ZAMS and TAMS (shown only in the Ks,(J-Ks) diagram), the
borders of the evolved Main Sequence stars;
Magenta dashed line: corresponds to the Ksmc;
Thick yellow circles: stars selected for age determination;
Black arrows: increasing interstellar extinction vectors.
MED:
Magenta solid lines correspond to the average proper motion of the
cluster; the magenta dashed line corresponds to the Ksmc.
CCD and QCD:
The Magenta curve corresponds to the apparent isochrone (observed magnitudes
and colours); the cyan curve corresponds to the intrinsic isochrone.
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 280 63 Catalog of parameters for new open clusters
index.dat 45 692 List of MWSC new candidates
notes.dat 152 692 Notes to MWSC new candidates
stars/* . 63 *Star catalogs for 63 sky areas
atlas/* . 126 *Two EPS pages with diagrams for each cluster
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Note on stars/*: The file names include the MWSC sequential number + 4000 and a
name of a cluster, preceeded by a prefix "2m_" e.g. "2m4005MWSC_4005.dat"
for the cluster MWSC_4005.
Note on atlas/*: The file names include the MWSC sequential number + 4000 and a
name of a cluster, e.g. "4005MWSC4005_map.eps.gz" for the 1st page with a
map as a basic panel, and "4005MWSC4005_cmd.eps.gz" for the 2nd page with
CMDs as basic panels.
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See also:
I/317 : The PPMXL Catalog (Roeser+ 2010)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/280 : All-sky Compiled Catalogue of 2.5 million stars (Kharchenko+ 2009)
J/A+A/543/A156 : MWSC I. Pipeline & fundamental parameters (Kharchenko+ 2012)
J/A+A/558/A53 : MWSC II. The catalogue of basic parameters (Kharchenko+ 2013)
J/A+A/568/A51 : MWSC III. 139 new open clusters (Schmeja+ 2014)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- MWSC [4001/4692] MWSC number
6- 22 A17 --- Name NGC, IC or other common designation
24 A1 --- Type [a,g,m,n,r,s] Cluster type (G1)
25 A1 --- n_Type [o,c] object or candidate
26- 34 F9.4 h RAhour Adopted cluster centre in
right ascension (J2000.0)
35- 42 F8.3 deg DEdeg Adopted cluster centre in
declination (J2000.0)
43- 50 F8.3 deg GLON Galactic longitude
51- 58 F8.3 deg GLAT Galactic latitude
59- 65 F7.3 deg r0 [0.01/0.05]?=0.000 Angular radius of the core
66- 72 F7.3 deg r1 [0.08/0.2] Angular radius of the central part
73- 79 F7.3 deg r2 [0.1/0.35] Angular radius of the cluster
80- 86 F7.2 mas/yr pmRA [-10/10] Average proper motion in RA*cos(DE)
87- 93 F7.2 mas/yr pmDE [-12/10] Average proper motion in DE
94-100 F7.2 mas/yr e_pm [0/1.2] Error of proper motion
101-108 F8.2 km/s RV ?=999.99 Average radial velocity
109-116 F8.2 km/s e_RV ?=99.99 Error of RV
117-122 I6 --- o_RV ?=0 Number of stars used for RV
123-128 I6 --- N1sr0 [2/9] Number of most probable (1σ)
members in r0
129-135 I7 --- N1sr1 [12/120] Number of most probable (1σ)
members in r1 (1)
136-142 I7 --- N1sr2 [22/315] Number of most probable (1σ)
members in r2
143-150 F8.0 pc d [700/4300] Distance from the Sun
151-157 F7.3 mag E(B-V) [0/1.9] Colour-excess in (B-V)
158-164 F7.3 mag MOD [9/14] Apparent distance modulus, mKs-MKs
165-171 F7.3 mag E(J-Ks) [0/0.9] Colour-excess in (J-Ks)
172-178 F7.3 mag E(J-H) [0/0.6] Colour-excess in (J-H)
179-185 F7.3 mag dH Correction to H mag of fitted isochrone
186-192 F7.3 [yr] logt [7.9/9.6] Logarithm of average age (2)
193-199 F7.3 [yr] e_logt [0.01/0.11]?=0.000 Error of logt
200-203 I4 --- Nt [0/14]?=-1 Number of stars used for logt
calculation (2)
204-211 F8.2 pc rc [0.3/5.8]?=0.00 King' core radius
212-219 F8.2 pc e_rc [0.1/3.9]?=0.00 Error of core radius
220-227 F8.2 pc rt [3/21]?=0.00 King' tidal radius
228-235 F8.2 pc e_rt [1/15]?=0.00 Error of tidal radius
236-243 F8.2 pc-2 k [0.02/16]?=0.00 King' normalization factor
244-251 F8.2 pc-2 e_k [0.02/6.2]?=0.00 Error of normalization factor
253-256 A4 --- Src Source for MWSC list and input parameters
(always "AIPk")
258-260 A3 --- SType Source object type (always blank)
262-269 F8.3 [Sun] [Fe/H] [-3/3]?=99.999 Metallicity
270-276 F7.3 [Sun] e_[Fe/H] [0/1]?=9.99 Error of Metallicity
277-280 I4 --- o_[Fe/H] [0/580]?=0 Number of line used for [Fe/H]
--------------------------------------------------------------------------------
Note on (1): This number of stars is used to compute the average promer motion.
Note on (2): logt has been set manually when Nt=-1.
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Byte-by-byte Description of file: index.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- MWSC [4001/4692] MWSC number
6- 22 A17 --- Name NGC, IC or other common designation
24 A1 --- flag [=:-&] Confirmation (=) flag (G2)
26 A1 --- Type [agmnrs] Cluster type (G1)
27 A1 --- n_Type [oc] object or candidate
29- 32 A4 --- Src Source for MWSC list and input parameters
(always "AIPk")
34- 36 A3 --- SType Source object type (always blank)
37- 45 I9 --- N [0/54381] Number of stars in MWSC sky area
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Byte-by-byte Description of file: notes.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- MWSC [4001/4692] MWSC number
6- 22 A17 --- Name NGC, IC or other common designation
24 A1 --- Flag [=:-&] Confirmation (=) flag (G2)
26 A1 --- Type [agmnrs] Cluster type (G1)
27 A1 --- n_Type [oc] object/candidate
29-152 A124 --- Note Text of note
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Byte-by-byte Description of file: stars/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.8 h RAhour Right Ascension J2000.0, epoch 2000.0
14- 26 F13.7 deg DEdeg Declination J2000.0, epoch 2000.0
27- 34 F8.3 mag Bmag ?=99.990 Blue magnitude (1)
35- 42 F8.3 mag Vmag ?=99.990 Visual or red magnitude (2)
43- 50 F8.3 mag Jmag 2MASS J magnitude
51- 58 F8.3 mag Hmag 2MASS H magnitude
59- 66 F8.3 mag Ksmag 2MASS Ks magnitude
67- 73 F7.3 mag e_Jmag Error of J magnitude
74- 80 F7.3 mag e_Hmag Error of H magnitude
81- 87 F7.3 mag e_Ksmag Error of Ks magnitude
88- 97 F10.2 mas/yr pmRA ?=9999.90 Proper Motion in RA*cos(DE)
98-107 F10.2 mas/yr pmDE ?=9999.90 Proper Motion in DE
108-115 F8.2 mas/yr e_pm ?=-9.99 Error of proper motion
116-124 F9.2 km/s RV ?=999.99 Radial velocity
125-131 F7.2 km/s e_RV ?=-9.99 Error of RV
133-135 A3 --- Qflg 2MASS (ph_qual) JHKs Photometric quality flag
136-138 A3 --- Rflg 2MASS (rd_flg) Source of JHKs default mag
139-141 A3 --- Bflg 2MASS (bl_flg) JHKs components fit to source
146-155 I10 --- 2MASS 2MASS (pts_key) Unique identifier in 2MASS
156-163 I8 --- ASCC ?=0 ASCC-2.5 number (Cat. I/280)
165-184 A20 --- SpType Spectral type and luminosity class
186-193 F8.4 deg Rcl Angular distance from cluster centre
194-195 I2 --- Ps [0/1] Spatial membership probability
196-203 F8.2 % Pkin [0/100] Proper motion membership probability
204-211 F8.2 % PJKs [0/100] Photometric JKs membership probability
212-219 F8.2 % PJH [0/100] Photometric JH membership probability
221-224 I04 --- MWSC [4001/4692] MWSC number of cluster
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Note (1): Blue magnitude, if the star is in the ASCC-2.5 (ASCC is not equal 0),
then this is the Johnson B magnitude from ASCC-2.5;
if the star is not in the ASCC-2.5 (ASCC = 0), then this is the photographic
blue magnitude from USNO-A2.0.
Note (2): Visual or red magnitude, if the star is in the ASCC-2.5
(ASCC is not equal 0), then this is the Johnson V magnitude from ASCC-2.5;
if the star is not in the ASCC-2.5 (ASCC = 0), then this is the photographic
red magnitude from USNO-A2.0.
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Global notes:
Note (G1): Cluster type as follows:
a = association
g = globular cluster
m = moving group
n = nebulosity/presence of nebulosity
r = remnant cluster
s = asterizm.
Note (G2): This column has the following meaning:
= = cluster parameters are determined
: = possibly this is a cluster, but parameters are not determined
- = it is not a cluster
& = duplicated/coincides with an other cluster
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Acknowledgements:
Ralf Scholtz, rdscholz(at)aip.de
(End) Patricia Vannier [CDS] 28-Aug-2015