J/AJ/147/7 Photometry and spectroscopy of NGC 6520 (Odell, 2014)
A new look at open cluster NGC 6520.
Odell A.P.
<Astron. J., 147, 7 (2014)>
=2014AJ....147....7O 2014AJ....147....7O
ADC_Keywords: Clusters, open ; Spectroscopy ; Photometry, CCD ;
Photometry, uvby ; Radial velocities
Keywords: open clusters and associations: general -
open clusters and associations: individual: NGC 6520
Abstract:
We use CCD and photoelectric photometry with Stromgren filters along
with medium resolution spectra to investigate NGC 6520, an open
cluster very nearly in the direction of the galactic center. We find
an age of 60Myr, a distance of 2kpc, and an average reddening
E(b-y)=0.295, which increases toward the south. The average
heliocentric radial velocity of the B stars is -29km/s, while the
velocity of the nearby Barnard 86 is about 0 (heliocentric; -11km/s
compared to the LSR). This velocity difference amounts to about 1.8kpc
since the cluster formed, implying that it is extremely doubtful
NGC6520 is related to Barnard 86.
Description:
Multiple CCD images of NGC 6520 were obtained with the Steward
Observatory 1.52m Kuiper telescope on UT 2000 April 3, using Stromgren
uvby filters with the BigCCD 4K camera.
We obtained spectra of 30 stars near the cluster center on UT 2012
July 7, and a second set of spectra for nine of those on July 8 with
the B&C spectrograph on the Steward Observatory 2.3m Bok telescope.
The spectrograph configuration was such as to produce 1.35Å (two
pixel) resolution. Wavelength coverage was about 3865Å to 4710Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 468 NGC 6520 photometry and spectroscopy results
list.dat 115 57 List of fits files
fits/* . 58 Individual fits files
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See also:
VII/118 : NGC 2000.0 (Sky Publishing, ed. Sinnott 1988)
VII/1 : Revised New General Catalogue (Sulentic+, 1973)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Zug [1/50]? The Zug (1937LicOB..18...89Z 1937LicOB..18...89Z) number
4- 10 A7 --- --- [Hayford]
12- 13 A2 --- Hay The Hayford (1932LicOB..16...53H 1932LicOB..16...53H) identifier
15- 16 I2 h RAh Hour of Right Ascension (J2000)
18- 19 I2 min RAm Minute of Right Ascension (J2000)
21- 24 F4.1 s RAs Second of Right Ascension (J2000)
26 A1 --- DE- Sign of the Declination (J2000)
27- 28 I2 deg DEd Degree of Declination (J2000)
30- 31 I2 arcmin DEm Arcminute of Declination (J2000)
33- 34 I2 arcsec DEs Arcsecond of Declination (J2000)
36- 41 F6.3 mag Vmag The V band magnitude (derived from y) (1)
43- 47 F5.3 mag b-y Stromgren (b-y) color index
49- 54 F6.3 mag m1 ? The m1 color index (2)
56- 60 F5.3 mag c1 ? The c1 color index (2)
62- 67 F6.3 mag (b-y)0 ? Intrinsic Stromgren (b-y) color index
69- 74 F6.3 mag V0mag ? Intrinsic V band magnitude
76- 80 F5.3 mag E(B-V) ? The (B-V) color excess
81 A1 --- f_E(B-V) [*] Extinction found from a plane fit to B stars
extinction (see section 3.1)
83- 88 A6 --- SpT Spectral type
90- 92 I3 km/s RV ? Radial velocity
93 A1 --- f_RV [n] No radial velocity measurement available
95 A1 --- Mm [N] Likely not a cluster member (see Section 3.3)
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Note (1): The details of the transformation to standard magnitudes are given
in the appendix of 1310.7227 (http://arxiv.org/abs/1310.7227).
Note (2): Missing values of m1 and c1 are due to large formal errors in the
faint, red stars.
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right Ascension J2000 (hours)
3 A1 --- --- [:]
4- 5 I2 min RAm Right Ascension J2000 (minutes)
6 A1 --- --- [:]
7- 11 F5.2 s RAs Right Ascension J2000 (seconds)
13 A1 --- DE- Declination J2000 (sign)
14- 15 I2 deg DEd Declination J2000 (degrees)
16 A1 --- --- [:]
17- 18 I2 arcmin DEm Declination J2000 (minutes)
19 A1 --- --- [:]
20- 23 F4.1 arcsec DEs Declination J2000 (seconds)
25- 34 A10 "Y-M-D" DateObs Observation date
36- 46 A11 --- FileName Name of FITS file in subdirectory fits (1)
48- 50 A3 --- --- [Zug]
52- 53 I2 --- Zug [1/50]? The Zug number
55- 61 A7 --- --- [Hayford]
63- 64 A2 --- Hay The Hayford (1932LicOB..16...53H 1932LicOB..16...53H) identifier
66- 70 A5 --- --- [Skiff]
72- 73 I2 --- Skiff [7/10]? The Skiff number
75- 85 A11 --- Name Common star name
87-100 A14 --- n_Zug Note on Zug number
102-115 A14 --- n_Hay Note on Hayford identifier
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Note (1): The file names are the original exposure number plus the aperture
number.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 26-Aug-2014