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We present high angular resolution measurements of the thermal Sunyaev–Zel’dovich effect (SZE) toward two galaxy clusters, RCS J2319+0038 at $z$= 0.9 and HSC J0947−0119 at $z$= 1.1, by the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. They are supplemented with available Chandra X-ray data, optical data taken by Hyper Suprime-Cam on Subaru, and millimeter-wave SZE data from the Atacama Cosmology Telescope. Taking into account departures from spherical symmetry, we have reconstructed non-parametrically the inner pressure profile of two clusters as well as electron temperature and density profiles for RCS J2319+0038. This is one of the first such measurements for an individual cluster at $z \gtrsim 0.9$. We find that the inner pressure profile of both clusters is much shallower than that of local cool-core clusters. Our results consistently suggest that RCS J2319+0038 hosts a weak cool core, where radiative cooling is less significant than in local cool cores. On the other hand, HSC J0947−0119 exhibits an even shallower pressure profile than RCS J2319+0038 and is more likely to be a non-cool-core cluster. The SZE centroid position is offset by more than 140 $h_{70}^{-1}$kpc from the peaks of galaxy distribution in HSC J0947−0119, suggesting a stronger influence of mergers in this cluster. We conclude that these distant clusters are at a very early stage of developing the cool cores typically found in clusters at lower redshifts.

We have observed the $J$$=$2–1 rotational emission line of PN toward the low-mass star forming region L 1157 with the Nobeyama 45 m telescope. The PN line has been detected toward the two shocked regions (B1 and B2) caused by the interaction between the blue lobe of the outflow from the protostar IRAS 20386$+$6751 and the ambient gas, whereas it has not been detected toward the protostar position. The fractional abundances of PN relative to H$_2$are evaluated to be (2–6) $\times$10$^{-10}$and (3–7) $\times$10$^{-10}$toward B1 and B2, respectively. Detection of PN in the B1 and B2 positions indicates that the formation of PN can be triggered by shocks. It seems most likely that PN is formed in the gas phase from PH$_3$evaporated from grain mantles, as suggested by the existing chemical model.

We have made mapping observations of L 1551 IRS 5, L 1551 NE, L 723, and L 43 and single-point observations of IRAS 16293$-$2422 in the submillimeter CS ($J$$=$7–6) and HCN ($J$$=$4–3) lines with Atacama Submillimeter Telescope Experiment (ASTE). Using the present data and our previous ASTE observations of L 483 and B 335 together, we found a definite correlation between source bolometric luminosities and total integrated intensities of the submillimeter lines ($I_{\rm CS}$$\propto$$L_{\rm bol}^{0.92}$). The combined ASTE $+$Submillimeter Array CS (7–6) image of L 1551 IRS 5 exhibits an extended ($\sim$2000 AU) component tracing the associated reflection nebula at west and southwest, as well as a compact ($\lesssim$500 AU) component centered on the protostellar position. The peaks of the CS and HCN emissions in L 1551 NE are not located at the protostellar position but offset ($\sim$1400 AU) toward the associated reflection nebula at west. By statistical analyses, we confirmed the velocity gradients of the CS (7–6) emission that are opposite to those of the millimeter lines along the outflow direction, which we reported in our early paper. The magnitudes of the submillimeter velocity gradients are estimated to be (9.7$\ \pm\ $1.7) $\times$10$^{-3}\ $km s$^{-1}\ $arcsec$^{-1}\ $in L 1551 IRS 5 and (7.6$\ \pm\ $2.4) $\times$10$^{-3}\ $km s$^{-1}\ $arcsec$^{-1}\ $in L 483. We suggest that the “skewed” submillimeter molecular emissions toward the associated reflection nebulae at a few thousand AU scale trace the warm ($\gtrsim$40 K) walls of the envelope cavities, excavated by the associated outflows and directly irradiated by the central protostars. The opposite velocity gradients along the outflow direction likely reflect the dispersing gas motion at the wall of the cavity in envelopes perpendicular to the outflow.

We present new, wide, and deep images in the 1.1 mm continuum and the $^{12}$CO ($J$$=$1–0) emission toward the northern part of the Orion A Giant Molecular Cloud (Orion-A GMC). The 1.1 mm data were taken with the AzTEC camera mounted on the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope in Chile, and the $^{12}$CO ($J$$=$1–0) data were with the 25 beam receiver (BEARS) on the Nobeyama Radio Observatory (NRO) 45 m telescope in the On-The-Fly (OTF) mode. The present AzTEC observations are the widest (1$^\circ\!\!\!.$7 $\times$2$^\circ\!\!\!.$3, corresponding to 12 pc $\times$17 pc) and the highest-sensitivity ($\sim\ $9 mJy beam$^{-1}$) 1.1 mm dust-continuum imaging of the Orion-A GMC with an effective spatial resolution of $\sim\ $40$”$. The $^{12}$CO ($J$$=$1–0) image was taken over the northern 1$^\circ\!\!\!.$2 $\times$1$^\circ\!\!\!.$2 (corresponding 9 pc $\times$9 pc) area with a sensitivity of 0.93 K in $T_{\rm MB}$, a velocity resolution of 1.0 km s$^{-1}$, and an effective spatial resolution of 21$”$. With these data, together with the MSX 8$\ \mu$m, Spitzer 24$\ \mu$m, and the 2MASS data, we have investigated the detailed structure and kinematics of molecular gas associated with the Orion-A GMC, and have found evidence for interactions between molecular clouds and the external forces that may trigger star formation. Two types of possible triggers were revealed: (1) Collisions of the diffuse gas on the cloud surface, particularly at the eastern side of the OMC-2/3 region, and (2) Irradiation of UV on the pre-existing filaments and dense molecular cloud cores. Our wide-field and high-sensitivity imaging has provided the first comprehensive view of the potential sites of triggered star formation in the Orion-A GMC.

In order to study how outflows from protostars influence the physical and chemical conditions of the parent molecular cloud, we have observed the Barnard 1 (B1) main core, which harbors four Class 0 and three Class I sources, in the CO (J = 1 - 0), CH3OH (JK = 2 K - 1 K ), and the SiO (J = 1 - 0) lines using the Nobeyama 45 m telescope. We have identified three CO outflows in this region: one is an elongated ([?]0.3 pc) bipolar outflow from a Class 0 protostar B1-c in the submillimeter clump SMM 2, another is a rather compact ([?]0.1 pc) outflow from a Class I protostar B1 IRS in the clump SMM 6, and the other is an extended outflow from a Class I protostar in SMM 11. In the western lobe of the SMM 2 outflow, both the SiO and CH3OH lines show broad redshifted wings with the terminal velocities of 25 km s-1 and 13 km s-1, respectively. It is likely that the shocks caused by the interaction between the outflow and ambient gas enhance the abundance of SiO and CH3OH in the gas phase. The total energy input rate by the outflows (1.1 x 10-3 L ) is smaller than the energy-loss rate (8.5 x 10-3 L ) through the turbulence decay in the B1 main core, which suggests that the outflows cannot sustain the turbulence in this region. Since the outflows are energetic enough to compensate the dissipating turbulence energy in the neighboring, more evolved star-forming region NGC 1333, we suggest that the turbulence energy balance depends on the evolutionary state of the star formation in molecular clouds.

We have performed detailed imaging and analyses of the Submillimeter Array observation in 230 GHz continuum, 12CO (2-1), 13CO (2-1), and C18O (2-1) emissions toward B335, an isolated and nearby ([?]150 pc) Bok globule with an embedded Class 0 source (L bol [?] 1.5 L ). We report the first discovery of high-velocity (V propagation[?] 160 km s-1) 12CO (2-1) jets with a size of [?]900 x 1500 AU along the east-west direction in B335. The estimated mass-loss rate ([?]2.3 x 10-7 M yr-1) and the momentum flux ([?]3.7 x 10-5 M yr-1 km s-1) of the 12CO jets in B335 are one order of magnitude lower than those of other 12CO jets in more luminous sources such as HH 211 (L bol [?] 3.6 L ) and HH 212 (L bol [?] 14 L ). The weaker jet activity in B335 could be due to the lower active accretion onto the central protostar. The C18O emission shows a compact ([?]1500 AU) condensation associated with the central protostar, and it likely traces the protostellar envelope around B335, as in the case of the 230 GHz continuum emission. The envelope exhibits a velocity gradient from the east (blueshifted) to west (redshifted) that can be interpreted as an infalling motion. The estimated central stellar mass, the mass infalling rate, and the accretion luminosity are 0.04 M , 6.9 x 10-6 M yr-1, and 2.1 L , respectively. On the other hand, there is no clear velocity gradient perpendicular to the outflow axis in the C18O envelope, suggesting little envelope rotation on a few hundred AU scale. The upper limits of the rotational velocity and specific angular momentum were estimated to be 0.04 km s-1 and 7.0 x 10-5 km s-1 pc at a radius of 370 AU, respectively. The specific angular momentum and the inferred Keplerian radius ([?]6 AU) in B335 are one to two orders of magnitude smaller than those in other more-evolved sources. Possible scenarios to explain the lower specific angular momentum in B335 are discussed.

We have conducted millimeter interferometric observations of the Orion Molecular Cloud-2 (OMC-2) FIR 6 region at an angular resolution of $\sim$4${}^{\prime\prime}$–7${}^{\prime\prime}$with the Nobeyama Millimeter Array (NMA). In the 3.3-mm continuum emission we detected dusty core counterparts of previously identified FIR sources (FIR 6a, 6b, 6c, and 6d), and moreover resolved FIR 6a into three dusty cores. The size and mass of these cores are estimated to be 1100–5900 AU and 0.19–5.5$ M_{\odot}$, respectively. We found that in the $^{12}$CO ($J$$=$1–0) emission FIR 6b, 6c, and 6d eject molecular outflow, and that the FIR 6c outflow also exhibits at least two collimated jet-like components in SiO ($J$$=$2–1) emission. At the tip of one of the SiO components there appears an abrupt increase in the SiO line width ($\sim$15 km s$^{-1}$), where the three resolved cores in FIR 6a seem to delineate the tip. These results imply the presence of the interaction and a bowshock front between the FIR 6c molecular outflow and FIR 6a. If the interaction occurred after the formation of the FIR 6a cores, the influence of the FIR 6c outflow on the FIR 6a cores would be minimal, since the total gravitational force in the FIR 6a cores (1.0–7.7 $\times$10$^{-4} M_{\odot} $km s$^{-1}$yr$^{-1}$) is much larger than the outflow momentum flux (2.4 $\times$10$^{-5} M_{\odot} $km s$^{-1}$yr$^{-1}$). On the other hand, it is also possible that the interaction caused the gravitational instability in FIR 6a, and triggered the fragmentation into three cores, since the separation among these cores ($\sim$2.0 $\times$10$^{3} $AU) is on the same order of the Jeans length ($\sim$5.0–8.4 $\times$10$^{3} $AU). In either case, FIR 6a cores, with a mass of 0.18–1.6$ M_{\odot}$and a density of 0.2–5.8 $\times$10$^{7} $cm$^{-3}$, might be potential formation sites of the next generation of cluster members.

The multiple protostellar system L1551 IRS5 exhibits a large-scale bipolar molecular outflow that spans [?]1.5 pc on both the northeast (redshifted) and southwest (blueshifted) sides of the system. We have studied this outflow within [?]4000 AU of its driving source(s) with the Submillimeter Array. Our CO(2-1) image at [?]4'' ([?]560 AU) resolution reveals three distinct components: (1) an X-shaped structure spanning [?]20'' from center with a similar symmetry axis and velocity pattern as the large-scale outflow; (2) an S-shaped structure spanning [?]10'' from center also with a similar symmetry axis but opposite velocity pattern to the large-scale outflow; and (3) a compact central component spanning [?]1.''4 from center again with a similar symmetry axis and velocity pattern as the large-scale outflow. The X-shaped component likely comprises the limb-brightened walls of a cone-shaped cavity excavated by the outflows from the two main protostellar components. The compact central component likely comprises material within this cavity newly entrained by one or both outflows from the two main protostellar components. The S-shaped component mostly likely comprises a precessing outflow with its symmetry axis inclined in the opposite sense to the plane of the sky than the other two components, taking the S-shaped component out of the cone-shaped cavity along most, if not all, of its entire length. This outflow may be driven by a recently reported candidate third protostellar component in L1551 IRS5, whose circumstellar disk is misaligned relative to the two main protostellar components. Gravitational interactions between this protostellar component and its more massive northern (and perhaps also southern) neighbor(s) may be causing the circumstellar disk and hence outflow of this component to precess.

For realizing high fidelity of imaging with mosaicing observations, the Atacama Large Millimeter/submillimeter Array (ALMA) consists of a homogeneous array of 12 m antennas (12 m Array) and the Atacama Compact Array (ACA) in order to cover all spatial frequency Fourier components of the brightness distribution of observed sources. The array is located at an altitude site of about 5000 m with an operating wavelength range of 0.3 to 3 mm. ACA is an array composed of four 12 m dishes [TP (Total Power) Array] and twelve 7 m dishes (7 m Array). The 7 m Array has a very compact configuration to take short-baseline data corresponding to the low spatial frequency Fourier components. The 7 m Array has two configurations extended over 30-50 m to avoid shadowing at low elevation. The scientific importances and operation concepts of ACA, and the system design of ACA and its performance are presented in this paper.

Using the ASTE 10 m submillimeter telescope and the 1.4 m Infrared Survey Facility (IRSF), we performed an extensive outflow survey in the Orion Molecular Cloud 2 and 3 region. Our survey, which includes 41 potential star-forming sites, has been newly compiled using multiwavelength data based on millimeter- and submillimeter-continuum observations, as well as radio continuum observations. From the CO(3-2) observations performed with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope, we detected 14 CO molecular outflows, seven of which were newly identified. This higher detection rate, as compared to previous CO(1-0) results in the same region, suggests that CO(3-2) may be a better outflow tracer. Physical properties of these outflows and their possible driving sources were derived. Derived parameters were compared with those of CO outflows in low- and high-mass star-forming regions. We show that the CO outflow momentum correlates with the bolometric luminosity of the driving source and with the envelope mass, regardless of the mass of the driving sources. In addition to these CO outflows, seven sources having near-IR features suggestive of outflows were also identified.

We have observed the Orion Molecular Cloud-2 FIR 3/4 region in the H13CO+ ( J = 1-0),12CO ( J = 1-0), SiO ( v = 0, J = 2-1), and CS ( J = 2-1) lines and the 3.3 mm continuum emission with the Nobeyama Millimeter Array (NMA) and in the CO ( J = 3-2) and CH3OH ( JK = 7K-6K) lines with Atacama Submillimeter Telescope Experiment (ASTE). Our NMA observations in the H13CO+ emission have revealed 0.07 pc scale dense gas associated with FIR 4 (FIR 4 clump). The 12CO ( J = 3-2,1-0) emission shows high-velocity blue- and redshifted components to both the northeast and southwest of FIR 3, suggesting an outflow from FIR 3 along the plane of the sky. The SiO and CH3OH emission, known as shock tracers, are detected around the interface between the outflow and FIR 4 clump. Furthermore, the 12CO ( J = 1-0) emission shows an L-shaped structure in the PV diagram. These results suggest the presence of an interaction between the outflow and FIR 4 clump. Moreover, our interferometric 3.3 mm continuum observations have first found that FIR 4 consists of 11 dusty cores at a scale of ~2000 AU. The separation among these cores (~ 5 x 103 AU) is on the same order of the Jeans length (~ 13 x 103 AU), and the estimated time scale of the fragmentation (~ 3.8 x 104 yr) is similar to the time scale of the outflow interaction (~ 1.4 x 104 yr). We suggest that the interaction triggered the fragmentation into these dusty cores, and hence the next generation of the cluster formation in FIR 4.

We have mapped the protobinary source IRAS 16293-2422 in CO 2-1,13CO 2-1, and CO 3-2 with the Submillimeter Array (SMA). The maps with resolution of 1.5 ''-5 '' reveal a single small-scale (~3000 AU) bipolar molecular outflow along the east-west direction. We found that the blueshifted emission of this small-scale outflow mainly extends to the east and the redshifted emission to the west from the position of IRAS 16293A. A comparison with the morphology of the large-scale outflows previously observed by single-dish telescopes at millimeter wavelengths suggests that the small-scale outflow may be the inner part of the large-scale (~15,000 AU) east-west outflow. On the other hand, there is no clear counterpart of the large-scale northeast-southwest outflow in our SMA maps. Comparing analytical models to the data suggests that the morphology and kinematics of the small-scale outflow can be explained by a wide-angle wind with an inclination angle of ~30deg-40deg with respect to the plane of the sky. The high-resolution CO maps show that there are two compact, bright spots in the blueshifted velocity range. An LVG analysis shows that the one located 1 '' to the east of source A is extremely dense, n(H2) ~107 cm[?]3, and warm, 55"/> Tkin > 55 K. The other one located 1 '' southeast of source B has a higher temperature of 65"/> Tkin > 65 K but slightly lower density of n(H2) ~106 cm[?]3. It is likely that these bright spots are associated with the hot core-like emission observed toward IRAS 16293. Since both bright spots are blueshifted from the systemic velocity and are offset from the protostellar positions, they are likely formed by shocks.

With the Submillimeter Array (SMA) we have made high angular resolution (~1'' = 160 AU) observations of the protobinary system IRAS 16293-2422 in the HCN (4-3), HC15N (4-3), and 354.5 GHz continuum emission. The HCN (4-3) line was also observed using the JCMT to supply missing short-spacing information. The submillimeter continuum emission is detected from the individual binary components of source A in the southeast and source B in the northwest, with a separation of ~5''. The optically thin HC15N (4-3) emission taken with the SMA has revealed a compact (~500 AU) flattened structure (P.A. = -16deg) at source A. This compact structure shows a velocity gradient along the projected minor axis, which can be interpreted as an infalling gas motion. Our HCN image including the short-spacing information shows an extended (~3000 AU) circumbinary envelope, as well as the compact structure at source A. A toy model consisting of a flattened structure with radial infall toward a 1 M central star reproduces the HCN/HC15N position-velocity diagram along the minor axis of the HC15N emission. In the extended envelope there is also a northeast (blue) to southwest (red) velocity gradient across the binary alignment, which is likely to reflect gas motion in the swept-up dense gas associated with the molecular outflow from source A. Only a weak and narrow (~2 km s-1) compact HC15N emission is associated with source B, where no clear molecular outflow is identified, suggesting the different evolutionary starges between sources A and B. Our study demonstrates the importance of adding short-spacing data to interferometer data in order to probe the detailed structure and kinematics of low-mass protostellar envelopes.

This paper presents a large spectral line and continuum survey of eight deeply embedded, low-mass protostellar cores using the SMA. High-excitation line emission from 11 molecular species originating in warm and dense gas has been imaged at high angular resolution (1''-3'', typically 200-600 AU) together with continuum emission at 230 GHz (1.3 mm) and 345 GHz (0.8 mm). Compact continuum emission is observed for all sources, which likely originates in marginally optically thick circumstellar disks, with typical lower limits to their masses of 0.1 M (1%-10% of the masses of their envelopes) and a dust opacity law, kn [?] nb, with b [?] 1. Prominent collimated outflows are present in CO 2-1 observations in all sources. The most diffuse outflows are found in the sources with the lowest ratios of disk to envelope mass, and it is suggested that these sources are in a phase where accretion of matter from the envelope has almost finished and the remainder of the envelope material is being dispersed by the outflows. Other characteristic dynamical signatures are inverse P Cygni profiles indicative of infalling motions seen in the 13CO 2-1 lines toward NGC 1333 IRAS 4A and NGC 1333 IRAS 4B. Outflow-induced shocks are present on all scales in the protostellar environments and are most clearly traced by the emission of CH3OH in NGC 1333 IRAS 4A and NGC 1333 IRAS 4B. These observations suggest that the emission of CH3OH and H2CO from these proposed ``hot corinos'' is related to the shocks caused by the protostellar outflows. Only one source, NGC 1333 IRAS 2A, has evidence for hot, compact CH3OH emission coincident with the embedded protostar.

We present ~2'' resolution CO (3-2), HCO+(4-3), and 880 mm continuum images of the luminous infrared galaxy NGC 6240 obtained at the Submillimeter Array. We find that the spatially resolved CO (3-2), HCO + (4-3), and the 880 mm emission peaks between the two nuclear components that are both known to harbor AGNs. Our large velocity gradient (LVG) analysis performed on each velocity channel suggests that the peak of the molecular gas emission traced in our observations is warm (T = 20-100 K), dense (nH2 = 105.0-105.4 cm-3), and moderately optically thin (t = 0.2-2) in the central 1 kpc. We also find large column densities of ~1023 cm-2. Such extreme conditions are observed over ~300 km s-1 centered around the CO-derived systemic velocity. The derived molecular gas mass from the CO (3-2) emission and a CO-to-H2 conversion factor commonly used for ULIRGs is (6.9 +- 1.7) x 109 M, and this is consistent with the mass derived from previous CO (2-1) observations. The gas is highly turbulent in the central kpc (DvFWZI ~ 1175 km s-1). Furthermore, possible inflow or outflow activity is suggested from the CO (3-2) velocity distribution. We tentatively state that 3.5 x 108 M of isolated CO (3-2) emission seen west of the northern disk may be associated with outflows from starburst superwinds, but the gas outflow scenario from one of the central AGN is not completely ruled out. Piecing all of the information together, the central region of NGC 6240 harbors 2 AGNs, ~1010 M of molecular gas mass, 5 x 107 M of dust mass, and has possible evidence of inflow and outflow activity.

With the ASTE telescope, we have observed three low-mass protostellar envelopes around L483, B335, and L723 in the submillimeter CS ($J$= 7$-$6) and HCN ($J$= 4$-$3) lines. We detected both the CS and HCN lines toward all targets, and the typical CS intensity ($\sim$1.0 K in $T_{\rm B}$) was twice higher than that of the HCN line. Mapping observations of L483 in these lines have shown that the submillimeter emissions are resolved, exhibit a western extension from the central protostar, and that the deconvolved size is $\sim$5500 AU $\times$3700 AU (PA = 78$^{\circ}$) in the HCN emission. The extent of the submillimeter emission in L483 implies the presence of higher temperature ($\gtrsim$40 K) gas at 4000 AU away from the central protostar, which suggests that we need to take 2-dimensional radiative transfer models with a bipolar cavity into account. The position–velocity diagrams of these submillimeter lines along the axis of the associated molecular outflow exhibit that the sense of the submillimeter velocity gradient is opposite to that of the millimeter observation or the associated molecular outflow, both in L483 and in B335. We suggest that expanding gas motions at the surface of the flattened envelope, which is irradiated by the central protostar directly, are the origin of the observed submillimeter velocity structure.

We present an observation of L1551 IRS 5 at 7 mm with an angular resolution as high as ~0.''04 (5 AU). Apart from the two main components oriented north-south with a projected separation of 47 AU, we discover a third component lying 13 AU to the southeast of the northern component, thereby making L1551 IRS 5 a triple protostellar system. The two main components comprise circumstellar dust disks with dimensions of ~17 AU, together with bipolar ionized jets collimated within a radial distance of [?]3 AU from their central protostars. The third component likely has an even smaller circumstellar dust disk with a dimension of ~9 AU. The relative proper motion of the two main components is consistent with a circular coplanar orbit with an orbital separation of ~50 AU, orbital period of ~380 yr, and total mass of ~0.9 M. Their measured disk sizes are smaller than the predicted gravitationally truncated sizes of ~26 AU. Together with the predicted minimum size for a circumbinary gap, noncircular coplanar orbits are constrained to an eccentricity [?]0.3. The disks of the two main components are accurately aligned with each other, as well as with a surrounding molecular pseudodisk. Furthermore, the clockwise orbital motion of these components coincides with the clockwise rotational motion of the pseudodisk. These attributes constitute a smoking gun for the formation of the two main components as a result of fragmentation within the inner regions of their parent pseudodisk. By contrast, the disk of the third component is significantly misaligned; measurements of its relative proper motion are required in order to help deduce its origin.

We report the results of H13CO+ (1-0), CO (1-0), and 3.3 mm dust continuum observations toward MMS 7, one of the strongest millimeter-wave sources in OMC-3, with the Nobeyama Millimeter Array (NMA) and the Nobeyama 45 m telescope. With the NMA, we detected centrally condensed 3.3 mm dust continuum emission, which coincides with the mid-infrared (MIR) source and the free-free jet. Our H13CO+ observations revealed a disklike envelope around MMS 7, whose size and mass are 0.15 x 0.11 pc and 5.1 M, respectively. The outer portion of the disklike envelope has a fan-shaped structure, which delineates the rim of the observed CO outflow. The position-velocity diagrams in the H13CO+ (1-0) emission show that the velocity field in the disklike envelope is composed of a dispersing gas motion and a possible rigid-like rotation. The mass-dispersing rate is estimated to be 3.4 x 10-5 M yr-1, which implies that MMS 7 has an ability to disperse ~10 M during the protostellar evolutional time. The specific angular momentum in the disklike envelope is nearly 2 orders of magnitude larger than that in low-mass cores. The turnover point of the power law of the angular momentum distribution in the disklike envelope ([?]0.007 pc), which is likely to be related to the outer radius of the central mass accretion, is similar in size to the 3.3 mm dust condensation. We propose that MMS 7 is in the last stage of the main accretion phase and that a substantial portion of the outer gas has already been dispersed, while mass accretion may still be ongoing at the innermost region, traced by the dusty condensation.

We present SiO $J = 8 \hbox{--} 7$(347.3 GHz) observations towards HH 212 (Herbig-Haro object 212) using the ASTE (Atacama Submillimeter Telescope Experiment) telescope. Our observations with a $22^{\prime\prime}$-diameter beam show that the SiO emission is highly concentrated within $1'$of the driving source. We carefully compare the SiO observations with archival $\mathrm{H}_2$1–0 S(1) images and published $\mathrm{H}_2$echelle spectra. We find that, although the SiO velocities closely match the radial velocities seen in $\mathrm{H}_2$, the distributions of $\mathrm{H}_2$and SiO emission differ markedly. We attribute the latter to the different excitation conditions required for $\mathrm{H}_2$and SiO emission, particularly the higher critical density ($n_{\mathrm{H}_2} \sim 10^8 \,\mathrm{cm}^{-3}$) of the SiO $J = 8 \hbox{--} 7$emission. The kinematic similarities imply that the $\mathrm{H}_2$and SiO are associated with the same internal working surfaces. We conclude that the SiO $J = 8 \hbox{--} 7$emission has a potential for probing the jet/wind launching region through interferometric observations in the future, particularly for the youngest, most deeply embedded protostars where IR observations are not possible.

We have carried out mapping observations of the molecular core associated with the young Class 0 protostar, IRAM 04191+1522, in the CH3OH (JK = 2K-1K) and C34S (J = 2-1) lines, using the 45 m telescope at Nobeyama Radio Observatory. Our observations have revealed that there is a condensation associated with the protostar, elongated in the east-west direction mostly perpendicular to the axis of the associated CO outflow. Its size and mass are estimated to be 0.07 x 0.04 pc and 2.3 M, respectively, from the CH3OH data. In addition to the elongated envelope, two compact (~0.03 pc) condensations were found in the CH3OH line at the southern edge of the elongated envelope, where the blueshifted CO outflow emerging from the protostar is located. In contrast to the elongated envelope, those compact CH3OH condensations show much larger line width (up to 2.0 km s-1), with centroid velocities blueshifted by ~0.8 km s-1. The compact condensations have momenta (~0.06 M km s-1) comparable to that of the blueshifted molecular outflow. In addition, they are gravitationally unbound, and most probably will dissipate eventually. These results suggest that the compact condensations are probably formed in the course of interaction between the outflow and the ambient gas surrounding the protostar and that such interaction may cause dissipation of a part of the ambient gas. No drastic, localized enhancement of the CH3OH abundance is, however, observed toward the compact condensations, implying that there seems to be no significant shock heating at the compact condensations, in spite of the interaction with the outflow. This may be because the CO outflow velocity (<10 km s-1) is too low to cause effective heating to release CH3OH on dust grains into the gas phase.

We have carried out detailed H13CO+ (J = 1-0) and CH3OH (JK = 20-10 A+) observations of two dense cores in the TMC-1C region with the 45 m telescope at Nobeyama Radio Observatory and the Nobeyama Millimeter Array (NMA). These two cores, H13CO+ core 2 and CH3OH core 6, were identified previously by the H13CO+ and CH3OH mapping observations of the entire TMC-1C region and show no sign of protostar formation. We found that the internal structure of H13CO+ core 2 is different from that of cores with class 0 protostars; this core consists of three velocity components and shows the radial column density distribution of ~r-0.43+-0.08, which is flatter than that in the protostellar cores (~r-1.0). The internal structure of CH3OH core 6 is different from that of H13CO+ core 2; the combined images of the 45 m and NMA data have revealed that there are three smaller scale CH3OH "clumps" ~2500 AU in size inside this core. The mass of the small-scale clumps, ~0.02 M, is much smaller than the virial mass (~0.3 M), suggesting that these clumps are gravitationally unbound. The velocity dispersion observed in these small-scale clumps is 0.45-0.5 km s-1, which is comparable to that of clumps with 0.02-0.03 pc in radius. A comparison of the velocity dispersion of the small-scale clumps and that of larger scale cores suggests that the velocity dispersion that follows the power law in the radius larger than ~0.02-0.03 pc turns into a constant value of ~0.45-0.5 km s-1 in the smaller size scale. The mass-size relation of the prestellar gas structures suggests that they follow the trend of constant gas density (~105 cm-3) in the radius from 0.006 to ~0.3 pc and that the smaller scale structures tend to be gravitationally unbound. The presence of the small clumps with substellar masses in prestellar cores implies that coalescence processes are likely to play an important role in forming protostars inside the cores. The observational difference of the internal structures among CH3OH core 6, H13CO+ core 2, and protostellar cores might represent the difference of the evolutionary stages.

We have investigated the evolution and distribution of molecules in collapsing prestellar cores via numerical chemical models, adopting the Larson-Penston solution and its delayed analogs to study collapse. Molecular abundances and distributions in a collapsing core are determined by the balance among the dynamical, chemical, and adsorption timescales. When the central density nH of a prestellar core with the Larson-Penston flow rises to 3 x 106 cm-3, the CCS and CO column densities are calculated to show central holes of radius 7000 and 4000 AU, respectively, while the column density of N2H+ is centrally peaked. These predictions are consistent with observations of L1544. If the dynamical timescale of the core is larger than that of the Larson-Penston solution owing to magnetic fields, rotation, or turbulence, the column densities of CO and CCS are smaller, and their holes are larger than in the Larson-Penston core with the same central gas density. On the other hand, N2H+ and NH3 are more abundant in the more slowly collapsing core. Therefore, molecular distributions can probe the collapse timescale of prestellar cores. Deuterium fractionation has also been studied via numerical calculations. The deuterium fraction in molecules increases as a core evolves and molecular depletion onto grains proceeds. When the central density of the core is nH = 3 x 106 cm-3, the ratio DCO+/HCO+ at the center is in the range 0.06-0.27, depending on the collapse timescale and adsorption energy; this range is in reasonable agreement with the observed value in L1544.

We have observed cyclic C$_3$H$_2$($J_{K_{a}K_{c}}= 2_{12}$–$1_{01}, 2_{02}$–$1_{11}, 3_{12}$–$3_{03}$) lines at the 3 mm wavelength region toward the starless TMC-1C cloud and the protostellar core of L 1527 with the 45 m telescope at Nobeyama Radio Observatory. In both clouds, the $2_{12}$–$1_{01}$and $2_{02}$–$1_{11}$lines are strongly detected, while the $3_{12}$–$3_{03}$line is only detected toward the center of the protostellar core L 1527. From our statistical equilibrium analyses of the ortho-C$_3$H$_2$($2_{12}$–$1_{01}$) and the para-C$_3$H$_2$($2_{02}$–$1_{11}$) lines, the ortho-to-para ratios of C$_3$H$_2$are determined to be $2.4\pm0.1$and $2.5\pm0.5$in TMC-1C and L 1527, respectively. These values are lower than the statistical value of 3, although the error of the ratio in L 1527 is large. Since thermal equilibrium with a dust temperature of 10 K still gives a ratio of 3 in c-C$_3$H$_2$, this result should suggest the lower ortho-to-para ratio of the precursor molecule, c-C$_3$H$_{3}^{+}$, which is thought to be mainly produced by C$_3$H$^{+} +$H$_2$. Thus, we conclude that the lower ortho-to-para ratio of c-C$_3$H$_2$is due to a lower ortho-to-para ratio of H$_{2}$than the statistical value.

We have mapped the Heiles cloud 2 region in the Taurus molecular cloud complex with H13CO+ (J = 1-0), CH3OH (JK = 20-10 A+), and C34S (J = 2-1) lines. Dense gas traced by the mapped lines with critical densities higher than 104 cm-3 is concentrated in four condensations, that is, the TMC 1 and TMC 1C filaments, L1527, and TMC 1A. We have found that the three emission lines have remarkably different spatial distributions. The H13CO+ emission traces well dense cores harboring protostars, while the CH3OH emission is weak toward the protostars and is rather enhanced toward cores without protostars. We found that there are two starless cores with enhanced CH3OH emission at the northwestern ends of the TMC 1 and TMC 1C filaments, toward which the H13CO+ emission is barely seen. On the basis of the analyses using the large velocity gradient (LVG) model, we show that the CH3OH abundance relative to H13CO+ is enhanced by up to 1 order of magnitude in the cores without protostars. The C34S abundance relative to H13CO+ also shows a similar trend to that of CH3OH. Such an abundance variation between H13CO+ and CH3OH and C34S can be explained in the scheme of time-dependent gas-phase chemical evolution, which predicts that CH3OH and C34S are abundant in the early stages of chemical evolution and become deficient in the later stages. A comparison of the spatial-velocity structures in TMC 1 observed with the three molecular lines suggests that this cloud consists of multiple components with different velocities and different chemical compositions along the line of sight.

We have mapped the entire TMC-1C region in the H13CO+ (J = 1-0) and CH3OH (JK = 20-10A+) lines at a grid spacing of 50'' with the 45 m telescope at Nobeyama Radio Observatory. We have also conducted high spatial resolution mapping observations of the TMC-1C region at a grid spacing of 34'' in both lines toward a 6' x 6' portion in the south and a 4' x 4' portion in the north. We found that the structure of TMC-1C is filamentary in both molecular lines. The size and position angle of the filament are 0.75 pc x 0.17 pc and 135deg, respectively. The filament consists of dense (~105 cm-3) cores which are traced by either H13CO+ or CH3OH lines. We found that the distribution of cores seen in H13CO+ is quite different from the distribution of cores seen in CH3OH. The large velocity gradient analyses indicate that this difference is a result of the relative abundance variation between H13CO+ and CH3OH in the cores by about 1 order of magnitude. We have also carried out multitransitional observations of C3H2 (JK',K'' = 21,2-10,1 and 31,2-30,3) at two positions in the same cloud in order to estimate the molecular hydrogen densities for H13CO+ and CH3OH cores and found that the densities are around 105 cm-3 for both cores. These starless cores (no IRAS source), considered to be prestellar cores, seem to be at chemically different evolutionary stages; the H13CO+ cores are more evolved and closer to protostar formation than CH3OH cores. On the other hand, we found no difference in physical properties, i.e., the size, line width, and mass, between H13CO+ and CH3OH cores; the averages are about 0.07 pc, 0.3 km s-1, and 2 M, respectively.

We present measurements of the thermal Sunyaev–Zel’dovich effect (SZE) toward SPT-CL J2334-4243 (the Phoenix galaxy cluster) at $z=0.597$by the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. The SZE is imaged at $5^{\prime \prime }$resolution (corresponding to the physical scale of $23\:h^{-1}\:$kpc) within $200\:h^{-1}\:$kpc from the central galaxy, with the peak signal-to-noise ratio exceeding 11. Combined with the Chandra X-ray image, the ALMA SZE data further allow for non-parametric deprojection of electron temperature, density, and entropy. Our method can minimize contamination by the central active galactic nucleus and the X-ray absorbing gas within the cluster, both of which greatly affect the X-ray spectrum. We find no significant asymmetry or disturbance in the SZE image within the current measurement errors. The detected SZE signal shows much higher central concentration than other distant galaxy clusters and agrees well with the average pressure profile of local cool-core clusters. Unlike in typical clusters at any redshift, the gas temperature drops by at least a factor of 5 toward the center. We identify $\sim\!\! 6 \times 10^{11}\, M_\odot$cool gas with temperature $\sim\!\! 3\:$keV in the inner $20\:h^{-1}\:$kpc. Taken together, our results imply that the gas is indeed cooling efficiently and nearly isobarically down to this radius in the Phoenix cluster.

We present the first image of the thermal Sunyaev–Zel'dovich effect (SZE) obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combining 7-m and 12-m arrays in Band 3, we create an SZE map toward a galaxy cluster RX J1347.5−1145 with 5″ resolution (corresponding to a physical size of 20 h−1kpc), the highest angular and physical spatial resolutions achieved to-date for imaging the SZE, while retaining extended signals out to 40″. The 1 σ statistical sensitivity of the image is 0.017 mJy beam−1or 0.12 mKCMBat the 5″ full width at half maximum. The SZE image shows a good agreement with an electron pressure map reconstructed independently from the X-ray data and offers a new probe of the small-scale structure of the intracluster medium. Our results demonstrate that ALMA is a powerful instrument for imaging the SZE in compact galaxy clusters with unprecedented angular resolution and sensitivity. As the first report on the detection of the SZE by ALMA, we present detailed analysis procedures including corrections for the missing flux, to provide guiding methods for analyzing and interpreting future SZE images obtained by ALMA.

Ground-based observations at terahertz (THz) frequencies are a newly explorable area of astronomy in the coming decades. We discuss science cases for a first-generation 10-m class THz telescope, focusing on the Greenland Telescope as an example of such a facility. We propose science cases and provide quantitative estimates for each case. The largest advantage of ground-based THz telescopes is their higher angular resolution (∼ 4″ for a 10-m dish), as compared to space or airborne THz telescopes. Thus, high-resolution mapping is an important scientific argument. In particular, we can isolate zones of interest for Galactic and extragalactic star-forming regions. The THz windows are suitable for observations of high-excitation CO lines and [N ii] 205-μm lines, which are scientifically relevant tracers of star formation and stellar feedback. Those lines are the brightest lines in the THz windows, so they are suitable for the initiation of ground-based THz observations. THz polarization of star-forming regions can also be explored since it traces the dust population contributing to the THz spectral peak. For survey-type observations, we focus on “sub-THz” extragalactic surveys, the uniqueness of which is detecting galaxies at redshifts z∼ 1–2, where the dust emission per comoving volume is the largest in the history of the Universe. Finally we explore possibilities of flexible time scheduling, which enables us to monitor active galactic nuclei, and to target gamma-ray burst afterglows. For these objects, THz and submillimeter wavelength ranges have not yet been explored.

We have conducted a spectral line survey of the 3 mm band with the 45 m telescope of Nobeyama Radio Observatory toward the L 1157 B1 shocked region, where the blue-shifted component of the bipolar outflow from the protostar IRAS 20386$ +$6751 interacts with the ambient gas. The observed frequency ranges from 78.1 to 115.8 GHz. We have detected 129 spectral lines of 29 molecular species. In addition to various oxygen-bearing organic molecules such as CH$ _3$CHO, HCOOCH$ _3$, and HCOOH, we have detected a phosphorus-containing molecule PN, a nitrogen-bearing organic molecule NH$ _2$CHO, and a carbon-chain molecule CCS in the shocked region. These results clearly indicate that the L 1157 B1 shocked region is chemically rich, which is probably triggered by evaporation of grain mantles.

We present imaging simulations of the Sunyaev–Zel'dovich effect of galaxy clusters for the Atacama Large Millimeter/submillimeter Array (ALMA), including the Atacama Compact Array (ACA). In its most compact configuration at 90 GHz, ALMA will resolve the intracluster medium with an effective angular resolution of 5$ ''$. It will provide a unique probe of shock fronts and relativistic electrons produced during cluster mergers at high redshifts, that are hard to spatially resolve by current and near-future X-ray detectors. The quality of image reconstruction is poor with the 12 m array alone, but improved significantly by adding ACA; the expected sensitivity of the 12 m array based on the thermal noise is not valid for the Sunyaev–Zel'dovich effect mapping unless accompanied by an ACA observation of at least equal duration. The observations above 100 GHz will become excessively time-consuming owing to the narrower beam size and the higher system temperature. On the other hand, significant improvement of the observing efficiency is expected once Band 1 is implemented in the future.

We have conducted a sensitive 3 mm observation toward the shocked region, Lynds 1157 B1, which is an interaction spot between a molecular outflow and its ambient gas. We have successfully detected the CH$_3$CHO, HCOOCH$_3$, and HCOOH lines, as well as the CH$_2$DOH line. The abundances of these molecules relative to CH$_3$OH are found to be lower than those in the low-mass star-forming core, IRAS 16293$-$2422. Since these molecules are thought to evaporate from grain mantles, the observational results mean that complex molecules are less abundant in grain mantles residing in the ambient cloud surrounding a prestellar/protostellar core. Instead, efficient formation of the complex organic species and deuterated species should take place in a prestellar/protostellar core. The present result verifies the importance of an unbiased line survey of this source.

We have observed dense gas around the Very Low Luminosity Objects (VeLLOs) L1521F-IRS and IRAM 04191+1522 in carbon-chain and organic molecular lines with the Nobeyama 45 m telescope. Toward L1521F-IRS, carbon-chain lines of CH3CCH (50-40), C4H ($\frac{17}{2}$-$\frac{15}{2}$), and C3H2 (212-101) are 1.5-3.5 times stronger than those toward IRAM 04191+1522, and the abundances of the carbon-chain molecules toward L1521F-IRS are 2-5 times higher than those toward IRAM 04191+1522. Mapping observations of these carbon-chain molecular lines show that in L1521F the peak positions of these carbon-chain molecular lines are different from each other and there is no emission peak toward the VeLLO position, while in IRAM 04191+1522 these carbon-chain lines are as weak as the detection limits, except for the C3H2 line. The observed chemical differentiation between L1521F and IRAM 04191+1522 suggests that the evolutionary stage of L1521F-IRS is younger than that of IRAM 04191+1522, consistent with the extent of the associated outflows seen in the 13CO (1-0) line. The non-detection of the organic molecular lines of CH3OH (6-2-7-1 E) and CH3CN (60-50) implies that the warm ([?]100 K) molecular-desorbing region heated by the central protostar is smaller than [?]100 AU toward L1521F-IRS and IRAM 04191+1522, suggesting the young age of these VeLLOs. We propose that the chemical status of surrounding dense gas can be used to trace the evolutionary stages of VeLLOs.