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J/A+A/527/A24     Spectra of low-mass stars in Upper Sco    (Lodieu+, 2011)

Multi-fibre optical spectroscopy of low-mass stars and brown dwarfs in Upper Scorpius. Lodieu N., Dobbie P.D., Hambly N.C. <Astron. Astrophys. 527, A24 (2011)> =2011A&A...527A..24L
ADC_Keywords: Clusters, open ; Stars, late-type ; Spectroscopy Keywords: technique: spectroscopic - galaxy: open clusters and associations: individual: Upper Scorpius - brown dwarfs - stars: luminosity function, mass function Abstract: We have obtained multi-fibre intermediate-resolution optical spectroscopy of 94 photometric and proper motion selected low-mass star and brown dwarf candidates in Upper Sco with the AAOmega spectrograph on the Anglo-Australian Telescope. We have estimated the spectral types and measured the equivalent widths of youth and gravity diagnostic features to confirm the spectroscopic membership of about 95% of the photometric and proper motion candidates extracted from 6.5 square degrees surveyed in Upper Sco by the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters Survey (GCS). We have estimated the effective temperatures and masses for each new spectroscopic member using the latest evolutionary models available for low-mass stars and brown dwarfs. Combining the current optical spectroscopy presented here with near-infrared spectroscopy obtained for the faintest photometric candidates, we confirm the shape and slope of our earlier photometric mass function. The luminosity function drawn from the spectroscopic sample of 113 USco members peaks at around M6 and is flat at later spectral type. The mass function may peak at 0.2M and is quite flat in the substellar regime. We observe a possible excess of cool low-mass brown dwarfs compared to IC 348 and the extrapolation of the field mass functions, supporting the original hypothesis that Upper Sco may possess an excess of brown dwarfs compared. Description: Coordinates (J2000), ZYJHK photometry from the UKIDSS Galactic Clusters Survey, and proper motions derived from the UKIDSS/2MASS cross-match (in arcsec/yr) of stars in the AAOmega field-of-view ordered by increasing Z magnitude. The last column provides a tentative estimate of the spectral type. Data obtained with the AAOmega spectrograph on the Anglo-Australian telescope in May 2007. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tableb1.dat 106 624 Coordinates, photometry and astrometry of field stars in the AAOmega field-of-view tablea5.dat 140 109 Confirmed spectroscopic members of the USco AAT/AAOmega (A) and Gemini/GNIRS (G) candid.dat 66 114 List of USco member candidates, with spectra sp/* 0 809 Fits files of spectra
Byte-by-byte Description of file: tableb1.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Right ascension (J2000.0) 4- 5 I2 min RAm Right ascension (J2000.0) 7- 11 F5.2 s RAs Right ascension (J2000.0) 13 A1 --- DE- Declination sign (J2000.0) 14- 15 I2 deg DEd Declination (J2000.0) 17- 18 I2 arcmin DEm Declination (J2000.0) 20- 23 F4.1 arcsec DEs Declination (J2000.0) 25- 30 F6.3 mag Zmag Z-band magnitude from the UKIDSS GCS 32- 37 F6.3 mag Ymag Y-band magnitude from the UKIDSS GCS 39- 44 F6.3 mag Jmag J-band magnitude from the UKIDSS GCS 46- 51 F6.3 mag Hmag H-band magnitude from the UKIDSS GCS 53- 58 F6.3 mag Kmag K-band magnitude from the UKIDSS GCS 60- 66 F7.2 mas/yr pmRA Proper motion in right ascension 68- 74 F7.2 mas/yr pmDE Proper motion in declination 76- 95 A20 --- SpType Spectral type of the object 97-106 A10 --- Name Object name given when assigning fibres, fieldNNNNN (1)
Note (1): spectra files are named sp/specfieldNNNNnorm.fits (in "sp" subdirectory)
Byte-by-byte Description of file: tablea5.dat
Bytes Format Units Label Explanations
1 A1 --- F [AG] A for AAT/AAOmega, G for Gemini/GNIRS 3- 4 I2 h RAh Right ascension (J2000.0) 6- 7 I2 min RAm Right ascension (J2000.0) 9- 13 F5.2 s RAs Right ascension (J2000.0) 14 A1 --- DE- Declination sign (J2000.0) 15- 16 I2 deg DEd Declination (J2000.0) 18- 19 I2 arcmin DEm Declination (J2000.0) 21- 24 F4.1 arcsec DEs Declination (J2000.0) 26- 31 F6.3 mag Jmag UKIDSS/J-band magnitude 33- 39 F7.1 0.1nm WHa1 ?=- Hα equivalent width 41- 46 F6.1 0.1nm WHa2 ?=- Hα equivalent width 48- 53 F6.1 0.1nm WHa3 ?=- Hα equivalent width 55- 59 F5.1 0.1nm WHa4 ?=- Hα equivalent width 61- 63 F3.1 0.1nm WNaI1 ?=- NaI equivalent width 65- 67 F3.1 0.1nm WNaI2 ?=- NaI equivalent width 69- 71 F3.1 0.1nm WNaI3 ?=- NaI equivalent width 73- 75 F3.1 0.1nm WNaI4 ?=- NaI equivalent width 77- 79 F3.1 0.1nm WKI1 ?=- KI equivalent width 81- 83 F3.1 0.1nm WKI2 ?=- KI equivalent width 85- 87 F3.1 0.1nm WKI3 ?=- KI equivalent width 89- 91 F3.1 0.1nm WKI4 ?=- KI equivalent width 93- 96 F4.2 --- TiO7140 ?=- TiO7140 spectral index 98-101 F4.2 --- TiO8465 ?=- TiO8465 spectral index 103-106 F4.2 --- Na8189 ?=- Na8189 spectral index 108-111 F4.2 --- PC3 ?=- PC3 spectral index (1) 113-115 F3.1 --- Sp3 ?=- M subclass of spectral type, derived from PC3 spectral index 117-121 F5.2 --- SpT M subclass of spectral type, estimated from spectral template 123-126 I4 K Teff Effective temperature 128-133 F6.3 Lsun Lbol Bolometric luminosity 135-140 F6.4 Msun Mass Derived mass
Note (1): defined in Martin et al., 1996ApJ...469..706M. Ratio of pseudo-continuums [in nm]: (823.5-286.5)/(754-758).
Byte-by-byte Description of file: candid.dat
Bytes Format Units Label Explanations
1- 11 F11.7 deg RAdeg Right ascension in decimal degrees (J2000) 13- 23 F11.7 deg DEdeg Declination in decimal degrees (J2000) 25- 26 I2 h RAh Right ascension (J2000.0) 28- 29 I2 min RAm Right ascension (J2000.0) 31- 35 F5.2 s RAs Right ascension (J2000.0) 37 A1 --- DE- Declination sign (J2000.0) 38- 39 I2 deg DEd Declination (J2000.0) 41- 42 I2 arcmin DEm Declination (J2000.0) 44- 47 F4.1 arcsec DEs Declination (J2000.0) 49- 60 A12 --- Name Candidate name, USco_candNNN 62 A1 --- Red [R] red spectrum in "sp" subdirectory (1) 66 A1 --- Blue [B] blue spectrum in "sp" subdirectory (1)
Note (1): spectra in "sp" subdirectory, * red (570-880nm) spectra files named specUScocandNNN_norm.fits * blue (370-570nm) spectra files named specUScocandNNNBLUEcomb.fits.
Acknowledgements: Nicolas Lodieu, nlodieu (at)iac.es
(End) Nicolas Lodieu [IAC Tenerife, Spain], Patricia Vannier [CDS] 17-Dec-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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