Chandra Observations of the Massive Stellar Cluster Trumpler 14 in Carina Leisa Townsley, Patrick Broos, Eric Feigelson Penn State University THE GREAT NEBULA IN CARINA * D = 2.8 kpc (Tapia et al. 2003, MNRAS 339, 44); 10’ ~8.1pc. Age ~1 Myr. X-RAYS FROM YOUNG STARS * Trumpler 14 (Tr14): a very rich cluster on the edge of the giant mo- OUR CHANDRA OBSERVATION * Aimpoint on HD 93129AB, Tr14’s central O2I -- lecular cloud Carina I, which contains several embedded IR sources. -59:25:00 O3V binary. Chandra detects 31 of the 37 O and * Tr14 contains at least 30 O and early-B stars, including an O2 star; Tr14 in Carina, 57-ksec ACIS-I: early-B stars in the ACIS FoV. evolved Wolf-Rayet stars are nearby (so maybe supernovae). 350--790 eV; 790--970 eV; * We find ~1600 point sources suffused by soft, * The massive young cluster Tr16, containing Eta Carinae, lies ~15’ SE of 970--1650~eV ; -59:30:00 bright diffuse emission. Tr14. The Carina complex contains at least 10 more young clusters. csmooth. * Based on other studies (e.g. Getman et al. 2005, APJS 160, * Images below are shown in Galactic coordinates to emphasize the 353) we expect only ~10% contamination from Carina superbubble. -59:35:00 foreground stars and background AGN. * This increases the number of known members of Tr14 and Tr16 by a factor of several and pro- -59:40:00 vides many identifications of pre-main se- quence members. 45:00.0 30.0 10:44:00.0 30.0 43:00.0 42:30.0 -59:32:30 40.0 HD 93129A 50.0 HD 93129B 2° × 1.8° visual image from N. 2° × 1.8° mid-IR image from MSX -59:33:00 Smith et al. 2000 (ApJ 532, L145): (MSX/IPAC/NASA): 8.28µm, 12.13µm, OIII, Hα, SII. 14.65µm. 10.0 - 0.40 ACIS-I aimpoint: 0.5--2 keV; 2--7 keV 20.0 10:44:00.0 58.0 56.0 10:43:54.0 287.5 287.4 287.3 EARLY O STAR SPECTRA -0.60 The earliest O stars in Tr14 were fit in XSPEC with thermal plasmas, wabs(vapec + vapec) or wabs(apec). Lx,corr is the full-band (0.5--8 keV) X-ray luminosity corrected for absorption. Smoothed Tr14 Diffuse HD 93129A HD 93129B -0.70 full-band L = 1.4×10³³ ergs/s x‚corr Lx‚corr = 0.2×10³³ ergs/s (0.5--7 keV) NH = 4×10²¹ cm-² NH = 2×10²¹ cm-² ACIS-I image of Tr14; dif- -0.80 fuse extrac- S3 Diffuse tion regions kT=0.6 keV kT=2.6 keV kT=0.5 keV 28' × 28' 2MASS image -0.90 of Tr16 and Tr14. marked. DIFFUSE X-RAY EMISSION INTERPRETATION * Point sources were extracted and masked using ACIS Extract HD 93250 HD 93128 * A modest Chandra/ACIS-I exposure of Tr14 in Carina reveals 1600 point L = 2.1×10³³ ergs/s x‚corr Lx‚corr = 0.1×10³³ ergs/s (www.astro.psu.edu/xray/docs/TARA/ae_users_guide.html); see poster by Patrick Broos. NH = 1×10²¹ cm-² sources, mostly members of the Tr14 and Tr16 massive stellar clusters. NH = 6×10²¹ cm-² * Diffuse regions and backgrounds were defined with SAOImage DS9. * Diffuse spectra were extracted using ACIS Extract, fit with XSPEC: wabs(apec+apec) for Tr14 dif- fuse, vapec (no absorption) for S3 diffuse. * HD 93129AB, a very early-type binary at the heart of Tr14, is resolved * Lx,corr and Sx,corr are the soft-band (0.5--2 keV) absorption-corrected X-ray luminosity and X-ray surface brightness, respectively. and the components are shown to possess very different X-ray spectra. Tr14 Diffuse L = 3.0×10³³ ergs/s kT=0.3 keV x‚corr Other O stars in the field show a similar mix of soft and hard spectra. kT=0.6 keV kT=3.3 keV Sx‚corr = 2.0×10³² ergs/s/pc-² NH = 0.7×10²¹ cm-² Tr14 Bkgd Hard emission may be due to colliding winds in yet-to-be-discovered -59:25:00 close binary systems or to complex magnetic field interactions. 30:00 kT=0.26 keV kT=0.62 keV * Soft diffuse X-ray emission pervades the Tr14 H II region and is resolved * HD 93129A, the prototype O2 If* star (Walborn et al. 2002, AJ 123, 2754) was from the point source population; it is most likely from the fast O-star 35:00 recently resolved into a 55-mas double (Nelan et al. 2004, AJ 128, 323). winds that thermalize and shock the surrounding media, although its * The hard X-ray component seen in its ACIS spectrum, along with S3 Diffuse Lx‚corr = 1.8×10³³ ergs/s spatial distribution is mysterious. -59:40:00 its high Lx and high abundances, suggests that HD 93129A may Sx‚corr = 1.3×10³² ergs/s/pc-² Tr14 Diffuse NH = 0 cm-² S3 Bkgd be a colliding-wind binary (Portegies Zwart, Pooley, & Lewin 2002, ApJ 574, 762). * We also see soft, bright diffuse emission requiring enhanced Ne and Fe 45:00 * Comparing its spectrum and Lx to HD 93250 above suggests kT=0.58 keV on the S2 and S3 off-axis CCDs, far from any of Carina’s massive stellar abund=0.3Zsol except that HD 93250 may also be a colliding-wind binary. Ne = 0.6, Fe = 0.7 clusters. This emission may be from a ``cavity’’ supernova remnant that -59:50:00 * An alternative explanation for the hard X-ray emission might be S3 Diffuse (e.g. Chu et al. 1993, ApJ 414, 213) exploded inside the Carina superbubble . magnetically-confined wind shocks (e.g. Stelzer et al. 2005, ApJS 160, 557), but 45:00.0 10:44:00.0 43:00.0 42:00.0 HD 93129A at least is known to be more than one star. * Diffuse emission in Tr14 not cospatial with the cluster’s stars!? * In contrast, HD 93129B and HD 93128 show soft X-ray spectra Support provided by Chandra X-ray Observatory grant GO4-5006X. * S3 emission appears brighter but has smaller intrinsic Lx, Sx. more typical of single O stars and are much fainter. .