J/A+A/578/A4 Photometry and motions in Arches and Quintuplet (Stolte+, 2015)
Circumstellar discs in Galactic center clusters:
Disc-bearing B-type stars in the Quintuplet and Arches clusters.
Stolte, A., Hussmann, B., Olczak, C., Brandner, W., Habibi, M., Ghez, A. M.
Morris, M. R., Lu, J. R., Clarkson, W. I., Anderson, J.
<Astron. Astrophys. 578, A4 (2015)>
=2015A&A...578A...4S 2015A&A...578A...4S
ADC_Keywords: Clusters, open ; Infrared sources ; Photometry, infrared ;
Proper motions
Keywords: techniques: high angular resolution -
open clusters and associations: individual: Quintuplet -
circumstellar matter -
open clusters and associations: individual: Arches -
astrometry - proper motions
Abstract:
We investigate the circumstellar disc fraction as determined from
L-band excess observations of the young, massive Arches and Quintuplet
clusters residing in the central molecular zone of the Milky Way. The
Quintuplet cluster was searched for L-band excess sources for the
first time. We find a total of 26 excess sources in the Quintuplet
cluster, and 21 sources with L-band excesses in the Arches cluster, of
which 13 are new detections. With the aid of proper motion membership
samples, the disc fraction of the Quintuplet cluster could be derived
for the first time to be 4.0±0.7. There is no evidence for a
radially varying disc fraction in this cluster. In the case of the
Arches cluster, a disc fraction of 9.2±1.2 approximately out to the
cluster's predicted tidal radius, r<1.5pc (Habibi et al.,
2013A&A...556A..26H 2013A&A...556A..26H, Cat. J/A+A/556/A26), is found. This excess
fraction is consistent with our previously found disc fraction in the
cluster in the radial range 0.3<r<0.8pc. In both clusters, the host
star mass range covers late A to early B-type stars, 2<M<15M_☉, as
derived from J-band photospheric magnitudes. We discuss the unexpected
finding of dusty circumstellar discs in these UV intense environments
in the context of primordial disc survival and formation scenarios of
secondary discs. We consider the possibility that the L-band excess
sources in the Arches and Quintuplet clusters could be the high-mass
counterparts to T Tauri pre-transitional discs. As such a scenario
requires a long pre-transitional disc lifetime in a UV intense
environment, we suggest that mass transfer discs in binary systems are
a likely formation mechanism for the B-star discs observed in these
starburst clusters.
Description:
Two to three epochs of photometry and astrometric imaging were
obtained in the Arches and Quintuplet clusters with the
VLT/NAOS-CONICA instrument from 2002 to 2012, covering timebaselines
from 3 to 5 years in each of five fields per cluster. Astrometry and
proper motions were derived from Ks imaging. The combination with
HST/WFC3 F127M and F153M imaging provided infrared colours, and NACO
L' observations were used to derive infrared excess emission. The
spatial resolution of all NAOS-CONICA observations was
27.1-milliarcseconds/pixel and 130mas/pixel for all WFC3 images. The
catalogue provides all epochs of Ks photometry and proper motions for
stars brighter than Ks=17.5mag. Proper motions are derived as the
positional difference between two astrometric epochs.
HST/WFC3 F127M and F153M photometry was converted to standard JH
photometry with colour equations provided in the paper.
L' photometry was referenced to the Spitzer/GLIMPSE survey with
uncertain zeropoints due to the large differences in spatial
resolution, and absolute values should be treated with care, while
relative photometry is robust.
Membership indicators are given as follows: 1: likely cluster member,
0: likely non-member, -1: unknown membership, -99: two epoch
measurements could not be obtained.
For Quintuplet cluster (tablee1.dat), an indication of cluster
membership is given as a formal probability in Field 2-5, where stars
with pclus>0.4 are likely member candidates. A value of -99.0
indicates that the corresponding photometry or astrometry could not be
obtained.
Objects:
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RA (2000) DE Designation(s)
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17 45 50.415 -28 49 21.84 Arches cluster = NAME ARCHES CLUSTER
17 46 15.13 -28 49 34.7 Quintuplet cluster = NAME QUINTUPLET CLUSTER
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablee1.dat 207 10308 Quintuplet cluster JHKsL' photometry and
proper motions
tablee2.dat 197 2284 Arches cluster JHKsL' photometry and proper motions
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See also:
II/319 : UKIDSS-DR9 LAS, GCS, and DXS Surveys (Lawrence+ 2012)
J/A+A/540/A57 : Quintuplet infrared photometry, masses (Hussmann+ 2012)
J/A+A/556/A26 : Arches cluster: IR phot., extinction and masses (Habibi+, 2013)
Byte-by-byte Description of file: tablee1.dat tablee2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [1/10308] Sequential number
within the cluster
9 I1 --- Fld [1/5] Field number
11- 17 F7.3 arcsec oRA [-48/45] Right ascension offset (J2000) (1)
19- 25 F7.3 arcsec oDE [-51/44] Declination offset (J2000) (1)
28- 33 F6.3 mag Jmag [11.7/25.3] HST/WFC3 F127M J photometry
37- 41 F5.3 mag e_Jmag [0/1.1] F127M J photometric uncertainty
44- 49 F6.3 mag Hmag [9.594/24.005] HST/WFC3 F153M H photometry
53- 57 F5.3 mag e_Hmag [0/1.1] F153M H photometric uncertainty
60- 67 F8.3 yr Epoch1 [2002/2009.3] Epoch of Ks1 astrometry
69- 75 F7.3 mag Ksmag1 ?=-99 VLT/CONICA Ks photometry 1st epoch
77- 83 F7.3 mag e_Ksmag1 ?=-99 Ks1 photometric uncertainty
86- 93 F8.3 yr Epoch2 [2008/2012.6] Epoch of Ks2 astrometry
95-101 F7.3 mag Ksmag2 ?=-99 VLT/CONICA Ks photometry 2nd epoch
103-109 F7.3 mag e_Ksmag2 ?=-99 Ks2 photometric uncertainty
112-119 F8.3 yr Epoch3 [2011/2012.5]?=-99 Epoch of Ks3 astrometry
121-127 F7.3 mag Ksmag3 ?=-99 VLT/CONICA Ks photometry 3rd epoch
129-135 F7.3 mag e_Ksmag3 ?=-99 Ks3 photometric uncertainty
137-143 F7.3 mag L'mag ?=-99 VLT/CONICA L' photometry
145-151 F7.3 mag e_L'mag ?=-99 L' relative photometric uncertainty
153-159 F7.3 mas/yr pmRA ?=-99 Proper motion in RA (2)
161-167 F7.3 mas/yr e_pmRA ?=-99 Proper motion RA uncertainty (3)
169-175 F7.3 mas/yr pmDE ?=-99 Proper motion in DE (2)
177-183 F7.3 mas/yr e_pmDE ?=-99 Proper motion DE uncertainty (3)
188-190 I3 --- Mmb [-1/1]?=-99 Membership indicator, 1=yes (4)
195-197 I3 --- Exc [0/1]?=-99 L' excess source indicator
201-207 F7.3 --- pMmb [0/1]? Membership probability indicator
(only in tablee1.dat) (5)
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Note (1): Positional offsets in Right Ascension and Declination are calculated
with respect to the central star Q12: RA=17:46:15.13, DE=-28:49:34.70 (J2000)
for Quintuplet cluster (tablee1) and with respect to
the central brightest Ks source: RA=17:45:50.415, DEC=-28:49:21.84(J2000)
for Arches cluster (tablee2).
Note (2): Proper motions are provided in milliarcseconds/year.
Proper motion were derived as the positional difference between the 2 epochs
with best astrometric performance:
Field 1: 2003-2008 (epoch1-epoch2)
Field 2: 2008-2011 (epoch1-epoch2)
Field 3: 2009-2012 (epoch2-epoch3)
Field 4: 2009-2012 (epoch2-epoch3)
Field 5: 2009-2012 (epoch1-epoch2)
Note (3): Proper motion uncertainties are dominated by the constant geometric
transformation uncertainty for brighter stars.
Note (4): Membership indicator is:
1 = likely member
0 = likely non-member
-1 = uncertain membership status
-99 = several epoch measurement not possible
Note (5): Only in tablee1.dat. For stars deviating significantly from the
cluster and field distributions, the membership probability could not be
determined. pclus has a value of -99.99 in these cases.
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Acknowledgements:
Andrea Stolte, astolte(at)astro.uni-bonn.de
(End) Andrea Stolte [Bonn Univ., Germany], Patricia Vannier [CDS] 06-Feb-2015