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J/MNRAS/450/3855    New OB star candidates in Carina Arm     (Mohr-Smith+, 2015)

New OB star candidates in the Carina Arm around Westerlund 2 from VPHAS+. Mohr-Smith M., Drew J.E., Barentsen G., Wright N.J., Napiwotzki R., Corradi R.L.M., Eisloffel J., Groot P., Kalari V., Parker Q.A., Raddi R., Sale S.E., Unruh Y.C., Vink J.S., Wesson R. <Mon. Not. R. Astron. Soc., 450, 3855-3873 (2015)> =2015MNRAS.450.3855M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, OB ; Photometry, SDSS ; Photometry, infrared ; Photometry, H-alpha Keywords: surveys - stars: early-type - stars: massive - dust, extinction - open clusters and associations: individual: Westerlund 2 - Galaxy: structure Abstract: O and early B stars are at the apex of galactic ecology, but in the Milky Way, only a minority of them may yet have been identified. We present the results of a pilot study to select and parametrize OB star candidates in the Southern Galactic plane, down to a limiting magnitude of g=20. A 2 deg2 field capturing the Carina Arm around the young massive star cluster, Westerlund 2, is examined. The confirmed OB stars in this cluster are used to validate our identification method, based on selection from the (u-g, g-r) diagram for the region. Our Markov Chain Monte Carlo fitting method combines VPHAS+ u, g, r, i with published J, H, K photometry in order to derive posterior probability distributions of the stellar parameters log(Teff) and distance modulus, together with the reddening parameters A0 and RV. The stellar parameters are sufficient to confirm OB status while the reddening parameters are determined to a precision of σ(A0)∼0.09 and σ(RV)∼0.08. There are 489 objects that fit well as new OB candidates, earlier than ∼ B2. This total includes 74 probable massive O stars, 5 likely blue supergiants and 32 reddened subdwarfs. This increases the number of previously known and candidate OB stars in the region by nearly a factor of 10. Most of the new objects are likely to be at distances between 3 and 6 kpc. We have confirmed the results of previous studies that, at these longer distances, these sight lines require non-standard reddening laws with 3.5<RV<4. Description: We make use of the photometry from two VPHAS+ fields, numbered 1678 and 1679, that are, respectively, centred on RA=10:18:10.91, DE=-58:03:52.3 (J2000) and on RA=10:25:27.27, DE=-58:03:52.3 (J2000). These were observed in succession in the u, g and r filters on the night of 2012 January 22. The red filter data in Hα, r and i were obtained on 2012 April 29. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table5.dat 244 1073 Positions and photometry of all 1073 objects table6.dat 98 1073 Derived parameters of all 1073 objects
See also: II/341 : VPHAS+ DR2 survey (Drew+, 2016) III/5 : Faint OB stars between Car and Cen (Lynga 1968) J/ApJS/87/197 : Carina OB2 association (Garcia+, 1993) J/A+A/477/593 : X-ray properties of Carina OB1 association (Antokhin+, 2008) J/ApJS/194/5 : Carina OB stars in the CCCP catalog (Gagne+, 2011) J/ApJS/194/6 : Candidate X-ray emitting OB stars in Carina (Povich+, 2011) J/ApJS/194/7 : X-ray properties of O and B stars in Carina (Naze+, 2011) J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011) J/A+A/549/A67 : Embedded YSOs in Carina Nebula complex (Gaczkowski+, 2013) J/A+A/572/A116 : The VISTA Carina Nebula Survey (Preibisch+, 2014) J/MNRAS/465/1807 : Deep OB star population in Carina (Mohr-Smith+, 2017) Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 4 I4 --- VPHAS VPHAS ID 6- 12 A7 --- MSPID MSP ID (Cl* Westerlund 2 MSP NNN in Simbad) 14- 17 I4 --- VAID ?=- Vargas Alvarez et al. (2013, Cat. J/AJ/145/125, [VKB2013] NNNN in Simbad) 19- 21 I3 --- TFTID ?=- Tsujimoto et al. ID (2007, Cat. J/ApJ/665/719) [TFT2007] NNN in Simbad) 23- 46 A24 --- SIMBAD Simbad ID 48- 65 A18 --- SpType Spectral type 67- 75 F9.5 deg RAdeg Right ascension (J2000) 77- 85 F9.5 deg DEdeg Declination (J2000) 87- 95 F9.5 deg GLON Galactic longitude 97-105 F9.5 deg GLAT Galactic latitude 107-108 I2 h RAh Right ascension (J2000) 110-111 I2 min RAm Right ascension (J2000) 113-117 F5.2 s RAs Right ascension (J2000) 119 A1 --- DE- Declination sign (J2000) 120-121 I2 deg DEd Declination (J2000) 123-124 I2 arcmin DEm Declination (J2000) 126-130 F5.2 arcsec DEs Declination (J2000) 132-138 F7.4 mag rmag VPHAS r magnitude 140-145 F6.4 mag e_rmag rms uncertainty on rmag 147-153 F7.4 mag gmag VPHAS g magnitude 155-160 F6.4 mag e_gmag rms uncertainty on gmag 162-168 F7.4 mag umag VPHAS u magnitude 170-175 F6.4 mag e_umag rms uncertainty on umag 177-183 F7.4 mag imag VPHAS i magnitude 185-190 F6.4 mag e_imag rms uncertainty on imag 192-198 F7.4 mag Hamag ?=- VPHAS Hα magnitude 200-205 F6.4 mag e_Hamag ?=- rms uncertainty on Hamag 207-212 F6.3 mag Jmag Published J magnitude 214-218 F5.3 mag e_Jmag rms uncertainty on Jmag 220-225 F6.3 mag Hmag Published H magnitude 227-231 F5.3 mag e_Hmag rms uncertainty on Hmag 233-238 F6.3 mag Kmag Published K magnitude 240-244 F5.3 mag e_Kmag rms uncertainty on Kmag
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 4 I4 --- VPHAS VPHAS ID 6- 10 F5.3 [K] logTeffP16 Effective temperature 16th percentile 12- 16 F5.3 [K] logTeffmed Median eEffective temperature (50th percentile) 18- 22 F5.3 [K] logTeffp84 Effective temperature 84th percentile 24- 29 F6.3 mag A0P16 monochromatic extinction at 4595Å (16th percentile) 31- 36 F6.3 mag A0med Median monochromatic extinction at 4595Å (50th percentile) 38- 43 F6.3 mag A0P84 monochromatic extinction at 4595Å (84th percentile) 45- 49 F5.3 --- RVP16 Ratio of total to selective extinction (16th percentile) 51- 55 F5.3 --- RVmed Median ratio of total to selective extinction (50th percentile) 57- 61 F5.3 --- RVP84 Ratio of total to selective extinction (84th percentile) 63- 68 F6.3 --- DMP16 Dispersion measure (16th percentile) 70- 75 F6.3 --- DMmed Median dispersion measure (50th percentile) 77- 82 F6.3 --- DMP84 Dispersion measure (84th percentile) 84- 91 F8.2 --- chi2 chi2 value 93- 98 A6 --- Notes Notes (1)
Note (1): The notes column indicates if the object shows emission (EM), is a subluminous candidate (SUB), is a blue supergiant candidate (BSG) or is a new O star candidate near Wd 2 (WD2) with similar reddening.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Aug-2017
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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