Aims. We derive physical properties such as the optical depths and the column densities of 13 CO and C 18 O to investigate the relationship between the far ultraviolet (FUV) radiation and the abundance ratios between 13 CO and C 18 O. and 0.4 × 10 15 < N C 18 O < 3.5 × 10 16 cm −2 , respectively. The abundance ratios between 13 CO and C 18 O, X13 CO /X C 18 O , are found to be 5.7−33.0. The mean value of X13 CO /X C 18 O in the nearly edge-on photon-dominated regions is found to be 16.47 ± 0.10, which is a third larger than that the solar system value of 5.5. The mean value of X13 CO /X C 18 O in the other regions is found to be 12.29 ± 0.02. The difference of the abundance ratio is most likely due to the selective FUV photodissociation of C 18 O.

We present the first results from a new, high resolution, 12 CO(1-0), 13 CO(1-0), and C 18 O(1-0) molecular line survey of the Orion A cloud, hereafter referred to as the CARMA-NRO Orion Survey. CARMA observations have been combined with single-dish data from the Nobeyama 45m telescope to provide extended images at about 0.01 pc resolution, with a dynamic range of approximately 1200 in spatial scale. Here we describe the practical details of the data combination in uv space, including flux scale matching, the conversion of single dish data to visibilities, and joint deconvolution of single dish and interferometric data. A ∆-variance analysis indicates that no artifacts are caused by combining data from the two instruments. Initial analysis of the data cubes, including moment maps, average spectra, channel maps, position-velocity diagrams, excitation temperature, column density, and line ratio maps provides evidence of complex and interesting structures such as filaments, bipolar outflows, shells, bubbles, and photo-eroded pillars. The implications for star formation processes are profound and follow-up scientific studies by the CARMA-NRO Orion team are now underway. We plan to make all the data products described here generally accessible; some are already available at [https://dataverse.harvard.edu/dataverse/CARMA-NRO-Orion].

We present the discovery of expanding spherical shells around low to intermediate-mass young stars in the Orion A giant molecular cloud using observations of 12 CO(1-0) and 13 CO(1-0) from the Nobeyama Radio Observatory 45-meter telescope. The shells have radii from 0.05 to 0.85 pc and expand outward at 0.8 to 5 km s −1 . The total energy in the expanding shells is comparable to protostellar outflows in the region. Together, shells and outflows inject enough energy and momentum to maintain the cloud turbulence. The mass-loss rates required to power the observed shells are two to three orders of magnitude higher than predicted for line-driven stellar winds from intermediate-mass stars. This discrepancy may be resolved by invoking accretion-driven wind variability. We describe in detail several shells in this paper and present the full sample in the online journal.

We present the results of observations toward a low-mass Class-0/I protostar [BHB2007]#11 (B59#11) in the nearby (d = 130 pc) star-forming region Barnard 59 (B59), in the Pipe Nebula. We utilize the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope (∼22 resolution), focusing on the CO(3-2), HCO + , H 13 CO + (4-3), and 1.1 mm dust-continuum emission transitions. We also show Submillimeter Array (SMA) data with ∼5 resolution in 12 CO, 13 CO, C 18 O(2-1), and 1.3 mm dust-continuum emission. From ASTE CO(3-2) observations, we found that B59#11 is blowing a collimated outflow whose axis lies almost on the plane of the sky. The outflow traces well a cavity-like structure seen in the 1.1 mm dust-continuum emission. The results of SMA 13 CO and C 18 O(2-1) observations have revealed that a compact and elongated structure of dense gas is associated with B59#11; the structure is oriented perpendicular to the outflow axis. There is a compact dust condensation with a size of 350 × 180 AU seen in the SMA 1.3 mm continuum map, and the direction of its major axis is almost the same as that of the dense gas elongation. The distributions of 13 CO and C 18 O emission also show velocity gradients along their major axes, which are thought to arise from the envelope/disk rotation. From detailed analysis of the SMA data, we infer that B59#11 is surrounded by a Keplerian disk with a radius of less than 350 AU. In addition, the SMA CO(2-1) image shows a velocity gradient in the outflow in the same direction as that of the dense gas rotation. We suggest that this velocity gradient indicates rotation in the outflow.

We present Orion A giant molecular cloud core catalogs, which are based on 1.1 mm map with an angular resolution of 36 ′′ (∼ 0.07 pc) and C 18 O (J=1-0) data with an angular resolution of 26.4 ′′ (∼ 0.05 pc). We have cataloged 619 dust cores in the 1.1 mm map using the Clumpfind method. The ranges of the radius, mass, and density of these cores are estimated to be 0.01 -0.20 pc, 0.6 -1.2 × 10 2 M ⊙ , and 0.3 × 10 4 -9.2 × 10 6 cm −3 , respectively. We have identified 235 cores from the C 18 O data. The ranges of the radius, velocity width, LTE mass, and density are 0.13 -0.34 pc, 0.31 -1.31 km s −1 , 1.0 -61.8 M ⊙ , and (0.8 -17.5) × 10 3 cm −3 , respectively. From the comparison of the spatial distributions between the dust and C 18 O cores, four types of spatial relations were revealed:(1) the peak positions of the dust and C 18 O cores agree with each other (32.4% of the C 18 O cores), (2) two or more C 18 O cores are distributed around the peak position of one dust core (10.8% of the C 18 O cores), (3) 56.8% of the C 18 O cores are not associated with any dust cores, and (4) 69.3% of the dust cores are not associated with any C 18 O cores. The data sets and analysis are public.1 The data sets and annotation files for M IRIAD and KARM A of Tables 2 and 4 are available at the NRO star-formation project web site via http://th.nao.ac.jp/MEMBER/nakamrfm/sflegacy/data.html . 2 James Clerk Maxwell Telescope 2.2. The C 18 O (J=1-0) emission line 2.2.1. Core identification in the C 18 O mapThe overall distribution of the C 18 O emission and the velocity structure are described by Shimajiri et al. (2014). To identify cores from the C 18 O (J=1-0) data, we applied the Clumpfind algorithm (Williams et al. 1994) to the C 18 O (J=1-0) cube data with an angular resolution of 26 ′′ .4 and a velocity channel width of 0.104 km s −1 . Here, note that we applied the Gaussian gridding convolution function (GCF) with 22 ′′ .5 FWHM size to the original C 18 O data, resulting in the effective angular resolution of 26 ′′ .4, and did no smoothing in

We report results of the 12 CO (J = 3 − 2) and HCO + (J = 4 − 3) observations of the W40 H ii region with the ASTE 10 m telescope (HPBW≃ 22 ′′ ) to search for molecular outflows and dense clumps. We found that the velocity field in the region is highly complex, consisting of at least four distinct velocity components at V LSR ≃ 3, 5, 7, and 10 km s −1 . The ∼7 km s −1 component represents the systemic velocity of cold gas surrounding the entire region, and causes heavy absorption in the 12 CO spectra over the velocity range 6 V LSR 9 km s −1 . The ∼5 and ∼10 km s −1 components exhibit high 12 CO temperature ( 40 K) and are found mostly around the H ii region, suggesting that these components are likely to be tracing dense gas interacting with the expanding shell around the H ii region. Based on the 12 CO data, we identified 13 regions of high velocity gas which we interpret as candidate outflow lobes. Using the HCO + data, we also

On the basis of various data such as ALMA, JVLA, Chandra, Herschel, and Spitzer, we confirmed that two protostellar candidates in Oph-A are bona fide protostars or proto-brown dwarfs (proto-BDs) in extremely early evolutionary stages. Both objects are barely visible across infrared (IR, i.e., near-IR to far-IR) bands. The physical nature of the cores is very similar to that expected in first hydrostatic cores (FHSCs), objects theoretically predicted in the evolutionary phase prior to stellar core formation with gas densities of ∼ 10 11−12 cm −3 . This suggests that the evolutionary stage is close to the FHSC formation phase. The two objects are associated with faint X-ray sources, suggesting that they are in very early phase of stellar core formation with magnetic activity. In addition, we found the CO outflow components around both sources which may originate from the young outflows driven by these sources. The masses of these objects are calculated to be ∼ 0.01 − 0.03 M from the dust continuum emission. Their physical properties are consistent with that expected from the numerical model of forming brown dwarfs. These facts (the X-ray detection, CO outflow association, and FHSC-like spectral energy distributions) strongly indicate that the two objects are proto-BDs or will be in the very early phase of protostars which will evolve more massive protostars if they gain enough mass from the surroundings. The ages of these two objects are likely to be within ∼ 10 3 years after the protostellar core (or second core) formation, taking into account the outflow dynamical times ( 500 yrs). Subject headings: stars:formation -stars:brown dwarfs -ISM:individual (Oph-A) -ISM:jets and outflow -X-rays: stars -submillimeter: stars 2.1. SMA Observations SM1-A was observed with the SubMillimeter Array (SMA) 1 on 2007 July 29 in its compact-north configuration over the hour angle coverage of -1.4 h to 4.2 h . Details of the SMA are described by Ho et al. (2004). These SMA data were originally taken for polarimetric measurements (S.P. Lai, private communication). The continuum data were first published in our previous paper (Nakamura et al. 2012), which describes the details of the observing parameters. Seven out of the eight SMA antennas were used, providing projected baseline lengths from 6.8 m to 125.5 m. The atmospheric transparency was good, with the 225 GHz opacity ranging from ∼0.05 to 0.09 measured at the nearby Caltech Submillimeter Observatory (CSO). The double sideband (DSB) receivers were tuned with a local oscillator (LO) frequency of 340.8 GHz. The IF frequency is 5 GHz, and in each sideband the correlator covers the 2 GHz bandwidth. Observations of NRAO 530 were interleaved with the target for gain calibration, whose absolute flux density at 340 GHz was measured to be 1.4 Jy by bootstrapping from observations of Uranus. The absolute flux accuracy is ∼15 %. Strong quasars 3C273 and 3C454.3 were adopted as the passband calibrators. The raw visibility data were calibrated with an IDL-based reduction package, MIR (Scovil...

We investigate the intrinsic abundance ratio of 13 CO to C 18 O and the X-factor in L 1551 using the Nobeyama Radio Observatory (NRO) 45 m telescope. L 1551 is chosen because it is relatively isolated in the Taurus molecular cloud shielded from FUV photons, providing an ideal environment for studying the target properties. Our observations cover~¢´¢ 40 40 with a resolution of~ 30 , which make up maps with the highest spatial dynamical range to date. We derive the X Xvalue on the sub-parsec scales in the range of ∼3-27 with a mean value of 8.0 ± 2.8. Comparing to the visual extinction map derived from the Herschel observations, we found that the abundance ratio reaches its maximum at low A V (i.e., A V ∼ 1-4 mag), and decreases to the typical solar system value of 5.5 inside L 1551 MC. The high X Xvalue at the boundary of the cloud is most likely due to the selective FUV photodissociation of C 18 O. This is in contrast with Orion-A where internal OB stars keep the abundance ratio at a high level, greater than ∼10. In addition, we explore the variation of the X-factor, because it is an uncertain, but widely used, quantity in extragalactic studies. We found that the X-factor µN H 1.0 2 , which is consistent with previous simulations. Excluding the high density region, the average X-factor is similar to the Milky Way average value.