J/AJ/142/140 Optical spectroscopy of {rho} Oph stars. II. (Erickson+, 2011) ================================================================================ The initial mass function and disk frequency of the {rho} Ophiuchi cloud: an extinction-limited sample. Erickson K.L., Wilking B.A., Meyer M.R., Robinson J.G., Stephenson L.N. =2011AJ....142..140E ================================================================================ ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Equivalent widths ; MK spectral classification Keywords: ISM: individual objects (rho Ophiuchi cloud) - open clusters and associations: individual (Upper Scorpius) - stars: formation - stars: pre-main sequence Abstract: We have completed an optical spectroscopic survey of an unbiased, extinction-limited sample of candidate young stars covering 1.3deg^2^ of the {rho} Ophiuchi star-forming region. While infrared, X-ray, and optical surveys of the cloud have identified many young stellar objects (YSOs), these surveys are biased toward particular stages of stellar evolution and are not optimal for studies of the disk frequency and initial mass function. We have obtained over 300 optical spectra to help identify 135 association members based on the presence of H{alpha} in emission, lithium absorption, X-ray emission, a mid-infrared excess, a common proper motion, reflection nebulosity, and/or extinction considerations. Description: Over 200 moderate resolution spectra were obtained for 184 stars identified through R- and I-band photometry as candidate YSOs. Fifty-two of these stars had spectral classifications reported in Paper I (Wilking et al., Cat. J/AJ/130/1733), allowing us to refine our previous spectral classifications. Newly observed YSO candidates numbered 133. These observations are described in detail in the following sections. Optical spectra were obtained for stars located over a 1.3deg^2^ area centered on L1688 using Hydra, the multi-fiber spectrograph, on two different telescopes. The first set of observations were made using Hydra on the Blanco 4m telescope at Cerro Tololo Inter-American Observatory on 2003 August 10-12. The second set of observations utilized Hydra on the WIYN6 3.5m telescope on 2006 June 15-17. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 156 219 Optical properties of candidate young stellar objects table3.dat 113 135 Association members with optical spectra -------------------------------------------------------------------------------- See also: J/ApJ/438/813 : Stellar population in {rho} Oph cloud core (Strom+, 1995) J/ApJS/112/109 : Rho Oph Near-IR Positions and Photometry (Barsony+, 1997) J/A+A/359/113 : X-ray and IR study of Rho Oph dark cloud (Grosso+, 2000) J/ApJ/613/393 : X-ray and radio sources in {rho} Oph Core A (Gagne+, 2004) J/A+A/429/963 : XMM-Newton observation of the rho Oph cloud (Ozawa+, 2005) J/ApJ/630/381 : Mid-IR imaging in {rho} Oph (Barsony+, 2005) J/A+A/447/609 : 1.2mm continuum observations in rho Oph cloud (Stanke+, 2006) J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006) J/ApJ/671/1800 : SCUBA observations of {rho} Oph cloud (Andrews+, 2007) J/A+A/485/155 : HK photometry of rho Oph PMS stars (Alves de Oliveira+, 2008) J/A+A/510/A98 : ^12^C^18^O(3-2) map of rho Oph A (Liseau+, 2010) J/A+A/515/A75 : {rho} Oph cloud low-mass population (Alves de Oliveira+, 2010) J/A+A/519/A34 : YSOs in DROXO (Deep rho Oph XMM obs.) (Pillitteri+, 2010) J/ApJ/719/550 : Deep NIR imaging of {rho} Oph cloud core (Marsh+, 2010) J/ApJ/751/22 : Candidates of the {rho} Oph cluster (Barsony+, 2012) J/AJ/130/1733 : Optical spectroscopy of {rho} Oph stars (Wilking+, 2005) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- ID HYDRA field and aperture number of observation (N-NN), DIFFERS from PAPER I (Wilking et al. 2005, Cat. J/AJ/130/1733) 6- 29 A24 --- Name Sources names from optical or infrared studies (1) 31- 51 A21 --- XName X-ray source association (2) 53- 54 I2 h RAh Right ascension (J2000) 56- 57 I2 min RAm Right ascension (J2000) 59- 62 F4.1 s RAs Right ascension (J2000) 64 A1 --- DE- Declination sign (J2000) 65- 66 I2 deg DEd Declination (J2000) 68- 69 I2 arcmin DEm Declination (J2000) 71- 72 I2 arcsec DEs Declination (J2000) 74- 77 A4 --- Li? [Yes: ] Li detection? (Yes or Yes:) 79 A1 --- l_EWHa Limit flag on EWHa 80- 86 F7.2 0.1nm EWHa ?=- H{alpha} equivalent width 87- 89 A3 --- n_EWHa uncertain value (:) or emission (+em) 92- 96 F5.2 mag Icmag ?=- Cousins I magnitude (3) 99-102 F4.2 mag Rc-Ic ?=- Cousins R-I colour index (3) 104-121 A18 --- SpType1 Previous spectral type with references (4) 123-135 A13 --- SpType2 Spectral type 137-144 A8 --- SpType Adopted spectral type 146-156 A11 --- Notes "Giant" or "Poss. dwarf" star -------------------------------------------------------------------------------- Note (1): Sources names from optical or infrared studies by: * (GSS, Source 2) Grasdalen et al. 1973ApJ...184L..53G * (VSSG) Vrba et al. 1975ApJ...197...77V * (VSS) Vrba et al. 1976AJ.....81..958V * (WSB) Wilking et al. 1987AJ.....94..106W * (WLY) Wilking et al. 1989ApJ...340..823W * (GY) Greene & Young 1992ApJ...395..516G * (ISO-Oph) Bontemps et al. 2001A&A...372..173B * (AOC) Alves de Oliveira & Casali 2008A&A...485..155A * (UCAC3) Zacharias et al. 2009, Cat. I/315 Note (2): X-ray source association from * the EINSTEIN survey by (ROX) Montmerle et al., 1983ApJ...269..182M, * the ROSAT surveys by (RXJ) Martin et al., 1998MNRAS.300..733M and * (ROXRF) Grosso et al., 2000A&A...359..113G, * the Chandra surveys by ([IKT2001]) Imanishi et al., 2001ApJ...557..747I and * (ROXC) N. Grosso 2005, private communication, or the XMM-Newton survey by * (ROXN) Ozawa et al., 2005A&A...429..963O. Note (3): R- and I-band photometry from this study except for ROX 3 which are from S. Gordon & K.M. Strom 1990, unpublished data. Note (4): References for spectral types: (BA) = Bouvier & Appenzeller, 1992A&AS...92..481B (MMGC) = Martin et al., 1998MNRAS.300..733M (LR) = Luhman & Rieke, 1999ApJ...525..440L (WMR) = Wilking et al., 2005AJ....130.1733W (G) = Geers et al., 2007A&A...476..279G -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- ID HYDRA field and aperture number of observation (N-NN), NOT AS IN PAPER I 6- 26 A21 --- Name Sources names from optical or infrared studies (1) 28- 31 A4 --- Source Name from Wilking et al. (2005, J/AJ/130/1733), N-NN 33- 37 A5 --- SpType Optical spectral types from this study or Wilking et al. (2005, J/AJ/130/1733) except noted 39- 45 A7 --- r_SpType Reference for spectral type (2) 47- 50 F4.1 mag AV Absorption in V band 52- 55 A4 --- r_AV Reference for AV (3) 58- 62 F5.2 mag IMAG Absolute I-band magnitude 64- 68 F5.3 [K] logTe Effective temperature 70- 74 F5.2 [Lsun] logL Luminosity 76- 79 F4.2 Msun Mass ?=- Stellar mass (4) 81 A1 --- l_logAge Limit flag on logAge 82- 85 F4.2 [yr] logAge ?=- Age 86- 90 A5 --- n_logAge Note on logAge 92-109 A18 --- Crit Criteria for young stellar association (5) 111-113 A3 --- Notes ? Pecularities of the source (6) -------------------------------------------------------------------------------- Note (1): Sources names from optical or infrared studies noted in Table 2 plus: (SR) = Struve & Rudkjobing, 1949ApJ...109...92S (DoAr) = Dolidze & Arakelyan, 1959AZh....36..444D (EL) = Elias, 1978ApJ...224..453E (Chini) = Chini, 1981A&A....99..346C (WL) = Wilking & Lada, 1983ApJ...274..698W (ROXR1) = Casanova et al., 1995ApJ...439..752C Note (2): Optical spectral types references as follows: (EL) = Elias, 1978ApJ...224..453E (CK) = Cohen & Kuhi, 1979ApJS...41..743C (HS) = Houk & Smith-Moore 1988, Vol. 4 Cat. III/133 (GS) = S. Gordon & K. M. Strom 1990, private communication (BA) = Bouvier & Appenzeller, 1992A&AS...92..481B (TQ) = Torres et al., 2006A&A...460..695T (MMGC) = Martin et al., 1998MNRAS.300..733M Note (3): R- and I-band magnitudes used to compute AV and Lbol are from this study except where noted, as follows: (C) = Chini 1981A&A....99..346C (GS) = S. Gordon & K. M. Strom 1990, private communication (BA) = Bouvier & Appenzeller 1992A&AS...92..481B (W) = Walter et al. 1994AJ....107..692W (2M) = denotes J- and H-band data from 2MASS were used to compute AV and Lbol and M(J) replaces M(I) in Column IMAG. Note (4): Masses and ages estimated from the tracks and isochrones of D'Antona & Mazzitelli 1997MmSAI..68..807D and F. D'Antona & I. Mazzitelli 1998, private communication except where noted in the last column. Note (5): Association membership established through * location above the main sequence and AV>1.5 mag (ext), * the presence of H{alpha} emission EW>10{AA}(ha), * an infrared excess (IRX), * lithium absorption (li), * proper motion (pm), * reflection nebulosity (ref. neb.), * near-infrared variability (var), or * X-ray emission (x). Note (6): Notes as follows: 1 = sits below main sequence, possible foreground star 2 = spectroscopic binary Casassus et al., 2008MNRAS.391.1075C 3 = mass and age derived from the tracks and isochrones of Palla & Stahler, 1999ApJ...525..772P 4 = subarcsecond companion observed in infrared and treated as a single object (Barsony et al. 2003ApJ...591.1064B; Prato 2007ApJ...657..338P) 5 = discordant proper motion (Mamajek 2008AN....329...10M) -------------------------------------------------------------------------------- History: From electronic version of the journal References: Wilking et al., Paper I 2005AJ....130.1733W, Cat. J/AJ/130/1733 ================================================================================ (End) Patricia Vannier [CDS] 18-Jan-2013