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 observation...

We present new high resolution (R ≃ 21, 000) near-infrared (λ = 2μm) spectroscopic observations of a sample of Class I and flat-spectrum protostellar objects in the ρ Ophiuchi dark cloud. None of the five Class I spectra show CO v = 0 – 2 absorption features, consistent with high K-band continuum veilings, 4 . rk . 20 and fast stellar rotation, assuming that the underlying protostellar photosph...

The evolution of the magnetic field and angular momentum in the collapsing cloud core is studied using three-dimensional resistive MHD nested grid simulations. Starting with a Bonnor-Ebert isothermal cloud rotating in a uniform magnetic field, we calculate the cloud evolution from the molecular cloud core (nc ≃ 10 4 cm, r = 4.6× 10 AU) to the stellar core (nc ≃ 10 22 cm, r ∼ 1R⊙), where nc and ...

We present analytic radiative transfer solutions for the spectra of unresolved, spherically symmetric, centrally heated, dusty sources. We find that the dust thermal spectrum possesses scaling relations that provide a natural classification for a broad range of sources, from low-mass protostars to dusty galaxies. In particular, we find that, given our assumptions, spectral energy distributions ...

We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the uniformly sampled spectral energy distributions, whose peaks are well sampled, we computed the Lbol, Tbol,and L L bol smm for these sources to search for correlations between far-IR CO emission and protostellar ...

The transformation of atomic hydrogen to molecular hydrogen through threebody reactions is a crucial stage in the collapse of primordial, metal-free halos, where the first generation of stars (Population III stars) in the Universe are formed. However, in the published literature, the rate coefficient for this reaction is uncertain by nearly an order of magnitude. We report on the results of bot...

We present high-resolution (R ≃ 18, 000), high signal-to-noise 2 μm spectra of two luminous, X-ray flaring Class I protostars in the ρ Ophiuchi cloud acquired with the NIRSPEC spectrograph of the Keck II telescope. We present the first spectrum of a highly veiled, strongly accreting protostar which shows photospheric absorption features and demonstrates the stellar nature of its central core. W...

Abstract To understand the formation process of massive stars, we present a multiscale and multiwavelength study W31 complex hosting two extended H ii regions (i.e., G10.30-0.15 (hereafter, W31-N) G10.15-0.34 W31-S)) powered by cluster O-type stars. Several Class i protostars total 49 ATLASGAL 870 ? m dust clumps (at d = 3.55 kpc) are found toward where some associated with molecular outflow ac...

We have obtained the full 1-200 μm spectrum of the low luminosity (36 L⊙) Class I protostar Elias 29 in the ρ Ophiuchi molecular cloud. It provides a unique opportunity to study the origin and evolution of interstellar ice and the interrelationship of interstellar ice and hot core gases around low mass protostars. We see abundant hot CO and H2O gas, as well as the absorption bands of CO, CO2, H...

We investigate the effect of radiative feedback on the star formation process using radiation hydrodynamical simulations. We repeat the previous hydrodynamical star cluster formation simulations of Bate et al., and Bate & Bonnell, but we use a realistic gas equation of state and radiative transfer in the flux-limited diffusion approximation rather than the original barotropic equation of state....