<i>Chandra</i>observations of the massive star-forming region S106

Giardino, G.; Favata, F.; Micela, G.

doi:10.1051/0004-6361:20040363

Cited by 13 publications

(17 citation statements)

References 26 publications

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“…IRS 1 and TC1 have L bol smaller by a factor of ∼ 20 compared with GGD 27-ILL, and IRS 4 is about a factor of 8-60 less luminous in X-rays than GGD 27-X. Furthermore, IRS 4 drives a "bipolar nebula" (Giardino et al 2004; see also Bally et al 1983) that may be the remnant of past outflow activity. This last interpretation is also consistent with its greater age (Table 3).…”

Section: Ggd 27-xmentioning

confidence: 97%

GGD 27: X-Rays From a Massive Protostar With an Outflow

Pravdo

Tsuboi

Suzuki

et al. 2008

ApJ

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We report the discovery of a cluster of Class I protostars in GGD 27. One of these protostars is the previously known, centrally located, GGD 27-ILL, which powers a massive bipolar outflow. We show that GGD 27-ILL, which is known to be the bright infrared (IR) source, IRAS 18162-2048, and a compact radio continuum source, is also the newly discovered hard X-ray source, GGD 27-X. The observations were made with the ACIS instrument on the Chandra X-ray Observatory. The X-rays from GGD 27-X are variable when compared with 4 years earlier, with an unabsorbed 2-10 keV X-ray luminosity in this observation of 1.5-12 × 10 31 erg s −1 and a plasma temperature of 10 7 K. The X-rays are probably associated with the underlying B0 star (rather than outflowing material), providing a rare glimpse in hard X-rays of an optically obscured massive protostar with an outflow. The X-ray luminosity and spectrum appear to be consistent with stars of its type in other star formation regions. Several other variable X-ray sources are also detected in the IR cluster that contains GGD 27-X. We also discuss another nearby cluster. In each of the clusters there is an object that is X-ray hard, highly absorbed at low energies, in a blank optical/IR/radio field, and variable in X-ray intensity by a factor of 10 on a timescale of 4 years. These latter objects may arise from more recent episodes of star formation or may be "hidden" Class III sources.

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Section: Ggd 27-xmentioning

confidence: 97%

GGD 27: X-Rays From a Massive Protostar With an Outflow

Pravdo

Tsuboi

Suzuki

et al. 2008

ApJ

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“…wind‐embedded shocks produced by instabilities inherent in radiatively driven winds; see Owocki, Castor & Rybicki 1988), yet the estimated stellar masses of these objects imply that they will have radiative outer envelopes which pose problems for the generation of X‐rays through magnetic star/disc interactions. In their observations of the S106 region, Giardino, Favata & Micela (2004) suggested that it may not be necessary to employ magnetic fields to explain the X‐ray emission characteristics of the massive central object S106 IRS 4 where the count rate was 0.30 ± 0.11 ks −1 .…”

Section: Introductionmentioning

confidence: 99%

The interactions of winds from massive young stellar objects: X-ray emission, dynamics and cavity evolution

Parkin¹,

Pittard²,

Hoare³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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Two-dimensional axis-symmetric hydrodynamical simulations are presented which explore the interaction of stellar and disc winds with surrounding infalling cloud material. The star and its accompanying disc blow winds inside a cavity cleared out by an earlier jet. The collision of the winds with their surroundings generates shock-heated plasma which reaches temperatures up to ∼10 8 K. Attenuated X-ray spectra are calculated from solving the equation of radiative transfer along lines of sight. This process is repeated at various epochs throughout the simulations to examine the evolution of the intrinsic and attenuated fluxes. We find that the dynamic nature of the wind-cavity interaction fuels intrinsic variability in the observed emission on time-scales of several hundred years. This is principally due to variations in the position of the reverse shock which is influenced by changes in the shape of the cavity wall. The collision of the winds with the cavity wall can cause clumps of cloud material to be stripped away. Mixing of these clumps into the winds mass-loads the flow and enhances the X-ray emission measure. The position and shape of the reverse shock play a key role in determining the strength and hardness of the X-ray emission. In some models the reverse shock is oblique to much of the stellar and disc outflows, whereas in others it is closely normal over a wide range of polar angles. For reasonable stellar and disc wind parameters, the integrated count rate and spatial extent of the intensity peak for X-ray emission agree with Chandra observations of the deeply embedded massive young stellar objects (MYSOs) S106 IRS 4, Mon R2 IRS 3A and AFGL 2591.The evolution of the cavity is heavily dependent on the ratio of the inflow to outflow ram pressures. The cavity closes up if the inflow is too strong and rapidly widens if the outflowing winds are too strong. The velocity shear between the respective flows creates Kelvin-Helmholtz instabilities which corrugate the surface of the cavity. Rayleigh-Taylorlike instabilities also occur when the cavity wall is pushed forcefully backwards by strong outflows. The opening angle of the cavity plays a significant role and we find that for collimation factors in agreement with those observed for bipolar jets around MYSOs, a reverse shock is established within 500 au of the star.

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“…Galactic massive SFRs with X-ray imaging surveys of their stellar contents include NGC 3603 (Moffat et al 2002), W3 (Hofner et al 2002), the Carina Nebula (Evans et al 2003(Evans et al , 2004Sanchawala et al 2007), NGC 6530 (Damiani et al 2004), the Trifid Nebula (Rho et al 2004), S106 (Giardino et al 2004), Ara OB1 (Skinner et al 2005), Cepheus B , RCW 38 (Wolk et al 2006), the Arches and Quintuplet clusters (Wang et al 2006), NGC 2362 (Delgado et al 2006), NGC 2264 (Flaccomio et al 2006), Westerlund 1 (Skinner et al 2006), IC 1396N ), NGC 6357 , the Rosette Nebula (Townsley et al 2003;J. Wang et al 2007, in preparation), M16 ( Linsky et al 2007), Cygnus OB2 (Albacete Colombo et al 2007), and M17 (Townsley et al 2003;Broos et al 2007).…”

Section: Introductionmentioning

confidence: 99%

An X‐Ray Imaging Study of the Stellar Population in RCW 49

Tsujimoto

Feigelson

Townsley

et al. 2007

ApJ

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We present the results of a high-resolution X-ray imaging study of the stellar population in the Galactic massive star-forming region RCW 49 and its central OB association Westerlund 2. We obtained a $40 ks X-ray image of a $17 0 ; 17 0 field using the Chandra X-Ray Observatory and deep NIR images using the Infrared Survey Facility in a concentric $8:3 0 ; 8:3 0 region. We detected 468 X-ray sources and identified optical, NIR, and Spitzer MIR counterparts for 379 of them. The unprecedented spatial resolution and sensitivity of the X-ray image, enhanced by optical and infrared imaging data, yielded the following results: (1) The central OB association Westerlund 2 is resolved for the first time in the X-ray band. X-ray emission is detected from all spectroscopically identified early-type stars in this region.(2) Most ($86%) X-ray sources with optical or infrared identifications are cluster members in comparison with a control field in the Galactic plane. (3) A loose constraint (2-5 kpc) for the distance to RCW 49 is derived from the mean X-ray luminosity of T Tauri stars. (4) The cluster X-ray population consists of low-mass pre-main-sequence and earlytype stars as obtained from X-ray and NIR photometry. About 30 new OB star candidates are identified. (5) We estimate a cluster radius of 6 0 -7 0 based on the X-ray surface number density profiles. (6) A large fraction ($90%) of cluster members are identified individually using complimentary X-ray and MIR excess emission. (7) The brightest five X-ray sources, two Wolf-Rayet stars and three O stars, have hard thermal spectra.

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Chandraobservations of the massive star-forming region S106

Cited by 13 publications

References 26 publications

GGD 27: X-Rays From a Massive Protostar With an Outflow

GGD 27: X-Rays From a Massive Protostar With an Outflow

The interactions of winds from massive young stellar objects: X-ray emission, dynamics and cavity evolution

An X‐Ray Imaging Study of the Stellar Population in RCW 49

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