Search

Aims. We present an analysis of the region IRAS 08589-4714 with the aim of characterizing the molecular environment. Methods. We observed the 12CO(3-2), 13CO(3-2), C18O(3-2), HCO+(3-2), and HCN(3-2) molecular lines in a region of 150″ × 150″, centered on the IRAS source, to analyze the distribution and characteristics of the molecular gas linked to the IRAS source. Results. The molecular gas distribution reveals a molecular clump that is coincident with IRAS 08589-4714 and with a dust clump detected at 1.2 mm. The molecular clump is 0.45 pc in radius and its mass and H2 volume density are 310 M⊙ and 1.2 × 104 cm-3, respectively. Two overdensities were identified within the clump in HCN(3-2) and HCO+(3-2) lines. A comparison of the LTE and virial masses suggests that the clump is collapsing in regions that harbor young stellar objects. An analysis of the molecular lines suggests that they are driving molecular outflows., Facultad de Ciencias Astronómicas y Geofísicas, Instituto Argentino de Radioastronomía

We study the emission by dust and stars in the Large and Small Magellanic Clouds, a pair of low-metallicity nearby galaxies, as traced by their spatially resolved spectral energy distributions (SEDs). This project combines Herschel Space Observatory PACS and SPIRE far-infrared photometry with other data at infrared and optical wavelengths. We build maps of dust and stellar luminosity and mass of both Magellanic Clouds, and analyze the spatial distribution of dust/stellar luminosity and mass ratios. These ratios vary considerably throughout the galaxies, generally between the range $0.01\leq L_{\rm dust}/L_\ast\leq 0.6$ and $10^{-4}\leq M_{\rm dust}/M_\ast\leq 4\times10^{-3}$. We observe that the dust/stellar ratios depend on the interstellar medium (ISM) environment, such as the distance from currently or previously star-forming regions, and on the intensity of the interstellar radiation field (ISRF). In addition, we construct star formation rate (SFR) maps, and find that the SFR is correlated with the dust/stellar luminosity and dust temperature in both galaxies, demonstrating the relation between star formation, dust emission and heating, though these correlations exhibit substantial scatter., 15 pages, 18 figures; ApJ, in press; version published in the journal will have higher-resolution figures

Aims. This work aims at investigating the molecular gas in the surroundings of the ultra-compact HII region G045.47+0.05 looking for evidence of molecular outflows. Methods. We carried out observations towards a region of 2 arcmin x 2 arcmin centered at RA=19h 14m 25.6s, dec.= 11deg 09m 27.6s (J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in the 12CO J=3-2, 13CO J=3-2, HCO+ J=4-3 and CS J=7-6 lines with an angular resolution of 22 arcsec. We complement these observations with public infrared data. Results. We characterize the physical parameters of the molecular clump where G045.47+0.0 is embedded. The detection of the CS J=7-6 line emission in the region reveals that the ultra-compact HII region G045.47+0.0 has not completely disrupted the dense gas where it was born. The HCO+ abundance observed towards G045.47+0.0 suggests the presence of molecular outflow activity in the region. From the analysis of the 12CO J=3-2 transition we report the presence of bipolar molecular outflows with a total mass of about 300 solar masses . We derive a dynamical time (flow's age) of about 10^5 yr for the outflow gas, in agreement with the presence of an ultra-compact HII region. We identify the source 2MASS 19142564+1109283 as the massive protostar candidate to drive the molecular outflows. Based on the analysis of its spectral energy distribution we infer that it is an early B-type star of about 15 solar masses. The results of this work support the scenario where the formation of massive stars, at least up to early B-type stars, is similar to that of low mass stars., Recently accepted for publication in A&A

Aims. This work aims at investigating the characteristics of the molecular gas associated with the nebula G18.8+1.8, which is linked to the Wolf-Rayet star HD 168206 (WR 113), and its relation to other components of its local interstellar medium. Methods. We carried out molecular observations of the 12CO(J = 1-0) and (J = 2-1) lines with an angular resolution of 44′′ and 22′′ using the SEST telescope. Complementary NANTEN data of the 12CO(1-0) line were also used. The dust emission was analyzed using Spitzer-IRAC images at 8.0 μm, and WISE data at 3.4 μm, 4.6 μm, and 12.0 μm. Results. The SEST data allowed us to identify a molecular component (Cloud 3) that has velocities in the interval from ~+30 to +36 km s -1 and is most probably linked to the nebula. Morphological and kinematical properties suggest that Cloud 3 consists of a wind-blown molecular half-shell, which expands around WR 113. The ratio R2-1/1-0 and excitation temperatures indicate that the molecular gas is being irradiated by strong UV radiation. The location of the inner optical ring in the outer edge of Cloud 3 suggests that the stars SerOB2-1,-2,-3,-63, and-64 are responsables for the ionization of Cloud 3 and the inner ring nebula. A comparison between the spatial distribution of the molecular gas and the PAH emission at 8 μm indicates the existence of a photodissociation region between the ionized and the molecular gas. A search for candidate young stellar objects (YSOs) in the region around G18.8+1.8 based on available 2MASS, MSX, IRAS, and Spitzer-IRAC catalogs resulted in the detection of about sixty sources, some of them projected onto Cloud 3. Two small spots of clustered candidate YSOs are projected near the outer border of Cloud 3, although a triggered stellar formation scenario is doubtful., Facultad de Ciencias Astronómicas y Geofísicas, Instituto Argentino de Radioastronomía

We present new near-infrared observations of the N11B nebula in the LMC. The presence of IR sources with intrinsic IR excess, a methanol maser and a very prominent PDR regions suggest strong star forming activity in N11B.

HESS J1858+020 is a weak gamma-ray source lying near the southern border of the SNR G35.6-0.4. A molecular cloud, composed by two clumps, shows signs of interaction with the SNR and with a nearby extended HII region. In particular, the southernmost clump coincides with the center of the HESS source. In this work we study this clump in detail with the aim of adding information that helps in the identification of the nature of the very-high energy emission. We observed the mentioned molecular clump using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3-2, 13CO J=3-2, HCO+ J=4-3 and CS J=7-6 lines with an angular resolution of 22". To complement this observations we analyzed IR and submillimeter continuum archival data. From the 12CO and 13CO J=3-2 lines and the 1.1 mm continuum emission we derived a density of between 10^{3} and 10^{4} cm^-3 for the clump. We discovered a young stellar object (YSO), probably a high mass protostar, embedded in the molecular clump. However, we did not observe any evidence of molecular outflows from this YSO which would reveal the presence of a thermal jet capable of generating the observed gamma-rays. We conclude that the most probable origin for the TeV gamma-ray emission are the hadronic interactions between the molecular gas and the cosmic rays accelerated by the shock front of the SNR G35.6-0.4., 11 pages, 5 figures. Accepted for publication in A&A (March 25, 2011)

We compare atomic gas, molecular gas, and the recent star formation rate (SFR) inferred from H-alpha in the Small Magellanic Cloud (SMC). By using infrared dust emission and local dust-to-gas ratios, we construct a map of molecular gas that is independent of CO emission. This allows us to disentangle conversion factor effects from the impact of metallicity on the formation and star formation efficiency of molecular gas. On scales of 200 pc to 1 kpc we find a characteristic molecular gas depletion time of ~1.6 Gyr, similar to that observed in the molecule-rich parts of large spiral galaxies on similar spatial scales. This depletion time shortens on much larger scales to ~0.6 Gyr because of the presence of a diffuse H-alpha component, and lengthens on much smaller scales to ~7.5 Gyr because the H-alpha and H2 distributions differ in detail. We estimate the systematic uncertainties in our measurement to be a factor of 2-3. We suggest that the impact of metallicity on the physics of star formation in molecular gas has at most this magnitude. The relation between SFR and neutral (H2+HI) gas surface density is steep, with a power-law index ~2.2+/-0.1, similar to that observed in the outer disks of large spiral galaxies. At a fixed total gas surface density the SMC has a 5-10 times lower molecular gas fraction (and star formation rate) than large spiral galaxies. We explore the ability of the recent models by Krumholz et al. (2009) and Ostriker et al. (2010) to reproduce our observations. We find that to explain our data at all spatial scales requires a low fraction of cold, gravitationally-bound gas in the SMC. We explore a combined model that incorporates both large scale thermal and dynamical equilibrium and cloud-scale photodissociation region structure and find that it reproduces our data well, as well as predicting a fraction of cold atomic gas very similar to that observed in the SMC., Accepted for publication in the Astrophysical Journal. 21 pages and 11 figures in apjemulate style

In order to precisely determine temperature and density of molecular gas in the Large Magellanic Cloud, we made observations of optically thin $^{13}$CO($J=3-2$) transition by using the ASTE 10m telescope toward 9 peaks where $^{12}$CO($J=3-2$) clumps were previously detected with the same telescope. The molecular clumps include those in giant molecular cloud (GMC) Types I (with no signs of massive star formation), II (with HII regions only), and III (with HII regions and young star clusters). We detected $^{13}$CO($J=3-2$) emission toward all the peaks and found that their intensities are 3 -- 12 times lower than those of $^{12}$CO($J=3-2$). We determined the intensity ratios of $^{12}$CO($J=3-2$) to $^{13}$CO($J=3-2$), $R^{12/13}_{3-2}$, and $^{13}$CO($J=3-2$) to $^{13}$CO($J=1-0$), $R^{13}_{3-2/1-0}$, at 45$\arcsec$ resolution. These ratios were used for radiative transfer calculations in order to estimate temperature and density of the clumps. The parameters of these clumps range kinetic temperature $T\mathrm{_{kin}}$ = 15 -- 200 K, and molecular hydrogen gas density $n(\mathrm{H_2})$ = 8$\times 10^2$ -- 7$\times 10^3$ cm$^{-3}$. We confirmed that the higher density clumps show higher kinetic temperature and that the lower density clumps lower kinetic temperature at a better accuracy than in the previous work. The kinetic temperature and density increase generally from a Type I GMC to a Type III GMC. We interpret that this difference reflects an evolutionary trend of star formation in molecular clumps. The $R^{13}_{3-2/1-0}$ and kinetic temperature of the clumps are well correlated with H$\alpha$ flux, suggesting that the heating of molecular gas $n(\mathrm{H_2})$ = $10^3$ -- $10^4$ cm$^{-3}$ can be explained by stellar FUV photons., Comment: 39 pages, 7 figures, 4 tables. Accepted for publication in The Astronomical Journal

The properties of the dust grains (e.g., temperature and mass) can be derived from fitting far-IR SEDs (>100 micron). Only with SPIRE on Herschel has it been possible to get high spatial resolution at 200 to 500 micron that is beyond the peak (~160 micron) of dust emission in most galaxies. We investigate the differences in the fitted dust temperatures and masses determined using only 200 micron data (new SPIRE observations) to determine how important having >200 micron data is for deriving these dust properties. We fit the 100 to 350 micron observations of the Large Magellanic Cloud (LMC) point-by-point with a model that consists of a single temperature and fixed emissivity law. The data used are existing observations at 100 and 160 micron (from IRAS and Spitzer) and new SPIRE observations of 1/4 of the LMC observed for the HERITAGE Key Project as part of the Herschel Science Demonstration phase. The dust temperatures and masses computed using only 100 and 160 micron data can differ by up to 10% and 36%, respectively, from those that also include the SPIRE 250 & 350 micron data. We find that an emissivity law proportional to lambda^-1.5 minimizes the 100-350 micron fractional residuals. We find that the emission at 500 micron is ~10% higher than expected from extrapolating the fits made at shorter wavelengths. We find the fractional 500 micron excess is weakly anti-correlated with MIPS 24 micron flux and the total gas surface density. This argues against a flux calibration error as the origin of the 500 micron excess. Our results do not allow us to distinguish between a systematic variation in the wavelength dependent emissivity law or a population of very cold dust only detectable at lambda > 500 micron for the origin of the 500 micron excess., 5 pages, 3 figurers, A&A, in press

The aim of this study was to evaluate the performance characteristics of an automated immunoassay for canine insulin-like growth factor 1 (IGF-1) measurement and to investigate the possible effects of some sources of variation, such as diurnal variations, feeding/fasting cycles, and glucocorticoid administration, in dogs. The immunoassay evaluated had an adequate analytical performance with intra- and inter-assay coefficients of variation (CVs) lower than 10%, linear regression equations with correlation coefficients of 0.9993 and 0.9988 after serial dilutions, and a limit of quantification of 7.1 ng/mL that was even lower than that reported by the manufacturer. The assay was significantly affected by hemolysis and lipemia producing a significant decrease in IGF-1 concentrations, but not by bilirubinemia.Serum IGF-1 concentrations did not show significant diurnal changes in fed or fasted dogs and were not affected by glucocorticoid administration.

Context. Previous Spitzer and IRAS observations of the LMC suggest an excess of FIR emission with respect to the gas surface density traced by ^(12)CO rotational emission lines and H_I 21 cm emission. This so-called “FIR excess” is especially noticeable near molecular clouds in the LMC, and has usually been interpreted as indicating the presence of a self-shielded H_2 component not traced by CO in the envelopes of molecular clouds. Aims. Based on Herschel HERITAGE observations taken as part of the science demonstration phase, we examine the correlation between gas and dust surface densities at higher resolution than previously achieved. We consider three additional possible causes for the FIR excess: X factor, FIR dust emissivity, and gas-to-dust ratio variations between the diffuse and dense phases of the ISM. Methods. We examine the structure of NT80 and NT71, two molecular clouds detected in the NANTEN ^(12)CO survey of the LMC. Dust surface density maps were derived from the HERITAGE data. The gas phase is traced by MAGMA ^(12)CO and ATCA+Parkes H_I 21 cm observations of the LMC. These data provide unprecedented resolution (1') to examine the structure of molecular clouds. The dust emissivity, gas-to-dust ratio, and X factor required to match the dust and gas surface densities are derived, and their correlations with the dust surface density are examined. Results. We show that the dust surface density is spatially correlated with the atomic and molecular gas phases. The dust temperature is consistently lower in the dense phase of the ISM than in the diffuse phase. We confirm variations in the ratio of FIR emission to gas surface density derived from H_I and CO observations. There is an excess of FIR emission, spatially correlated with regions of intermediate H_I and dust surface densities (A_V = 1−2), and little or no CO.While there is no significant trend in the dust emissivity or gas-to-dust ratio with dust surface density, the X factor is enhanced at A_V = 1−2. We conclude that H_2 envelopes not traced by CO and X factor variations close to the CO boundary may be more likely to cause these deviations between FIR emission and gas surface density than gas-to-dust ratio or emissivity variations.

We present here the first results from a high-resolution survey of the 12CO(J=1-0) emission across the northern part of the poorly-enriched Small Magellanic Cloud, made with the ATNF Mopra telescope. Three molecular complexes detected in the lower resolution NANTEN survey are mapped with a beam FWHM of ~42'', to sensitivities of approximately 210 mK per 0.9 km/s channel, resolving each complex into 4-7 small clouds of masses in the range of Mvir~10^3-4 Msol and with radii no larger than 16 pc. The northern SMC CO clouds follow similar empirical relationships to the southern SMC population, yet they appear relatively under-luminous for their size, suggesting that the star-forming environment in the SMC is not homogeneous. Our data also suggests that the CO cloud population has little or no extended CO envelope on scales, 12 pages, 8 Figures. Accepted for publication in ApJ, March 2010

This work aims at investigating the molecular and infrared components in the massive young stellar object (MYSO) candidate IRAS 18544+0112. The purpose is to determine the nature and the origin of this infrared source. To analyze the molecular gas towards IRAS 18544+0112, we have carried out observations in a 90" x 90" region around l = 34.69, b = -0.65, using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3-2, 13CO J=3-2, HCO+ J=4-3 and CS J=7-6 lines with an angular resolution of 22". The infrared emission in the area has been analyzed using 2MASS and Spitzer public data. From the molecular analysis, we find self-absorbed 12CO J=3-2 profiles, which are typical in star forming regions, but we do not find any evidence of outflow activity. Moreover, we do not detect either HCO+ J=4-3 or CS J=7-6 in the region, which are species normally enhanced in molecular outflows and high density envelopes. The 12CO J=3-2 emission profile suggests the presence of expanding gas in the region. The Spitzer images reveal that the infrared source has a conspicuous extended emission bright at 8 um with an evident shell-like morphology of ~ 1.5 arcmin in size (~ 1.4 pc at the proposed distance of 3 kpc) that encircles the 24 um emission. The non-detection of ionized gas related to IRAS 18544+0112, together with the fact that it is still embedded in a molecular clump suggest that IRAS 18544+0112, has not reached the UCHII region stage yet. Based on near infrared photometry we search for YSO candidates in the region and propos that 2MASS 18565878+0116233 is the infrared point source associated with IRAS 18544+0112. Finally, we suggest that the expansion of a larger nearby HII region, G034.8-0.7, might be related to the formation of IRAS 18544+0112., Comment: 14 pages, accepted for publication in A&A. Figures degraded to reduce file size

We present clumps of dust emission from Herschel observations of the Large Magellanic Cloud (LMC) and their physical and statistical properties. We catalog cloud features seen in the dust emission from Herschel observations of the LMC, the Magellanic type irregular galaxy closest to the Milky Way, and compare these features with HI catalogs from the ATCA+Parkes HI survey. Using an automated cloud-finding algorithm, we identify clouds and clumps of dust emission and examine the cumulative mass distribution of the detected dust clouds. The mass of cold dust is determined from physical parameters that we derive by performing spectral energy distribution fits to 250, 350, and 500 micronm emission from SPIRE observations using DUSTY and GRASIL radiative transfer calculation with dust grain size distributions for graphite/silicate in low-metallicity extragalactic environments. The dust cloud mass spectrum follows a power law distribution with an exponent of gamma=-1.8 for clumps larger than 400 solar mass and is similar to the HI mass distribution. This is expected from the theory of ISM structure in the vicinity of star formation., 4 pages, 4 figures, to appear in A&A special issue

The 30 Doradus region in the Large Magellanic Cloud is one of the most outstanding star forming regions of the Local Group and a primary target to study star formation in an environment of low metallicity. In order to obtain a more complete picture of the not yet consumed or dispersed cool gas, we searched for line emission from molecular clouds that could be associated with molecular hydrogen emission detected in the region. We obtained a high sensitivity 12CO J=2-1 map with the 15-m SEST telescope, complemented by pointed observations of 13CO J=2-1 and CS J=2-1. We report the discovery of a dense molecular cloud towards an embedded young massive star at ~ 20" (~5 pc, at the distance of 50 kpc) northwest of R136, the compact massive central stellar cluster powering 30 Doradus in the LMC, that could be triggering star formation in the surrounding molecular clouds. We derived a molecular mass of $\lesssim 10^4$ \msol, a linear radius of 3 pc, as an upper limit, and a mean density of $\gtrsim 10^{3}$ cm$^{-3}$ for the cloud. The detection of CS J=2-1 emission line indicates larger densities, $\sim 10^{6}$ cm$^{-3}$. The dense molecular cloud is associated with molecular 2.12 um H2 emission. We suggest that the observed molecular gas could be the remains of dense molecular material surviving the action of strong UV fields and winds in which the young massive star has formed., Comment: 10 pages, 3 figures, accepted in A&A

We present new observations of a sample of blue dwarf galaxies in the lines of CO(3–2) and HCN(4–3). The observations were obtained with the 12 m APEX telescope located at an altitude of 5100 m in Chajnantor (ALMA site). We detected CO(3–2) emission in seven of nine observed galaxies in our sample. In two galaxies, NGC 5253 and He 2–10, we mapped the central 20 �� × 20 �� in the CO(3–2) emission line. In He 2–10, we detected an extended component of molecular gas to the north-east of the main body of the galaxy. Comparing our data with previous HI and CO observations, we speculate that the presence of this detached cloud of molecular gas is produced by the merger already known in He 2–10, and could lead to the formation of a small tidal dwarf galaxy. The HCN(4–3) line was observed in NGC 5253 and He 2–10 only, but not detected.

New 12CO J=4-3 and 13CO J=3-2 observations of the N159 region in the Large Magellanic Cloud have been made. The 12CO J=4-3 distribution is separated into three clumps. These new measurements toward the three clumps are used in coupled calculations of molecular rotational excitation and line radiation transfer, along with other transitions of the 12CO as well as the isotope transitions of 13CO. The temperatures and densities are determined to be ~70-80K and ~3x10^3 cm-3 in N159W and N159E and ~30K and ~1.6x10^3 cm-3 in N159S. These results are compared with the star formation activity. The N159E clump is associated with embedded cluster(s) as observed at 24 micron and the derived high temperature is explained as due to the heating by these sources. The N159E clump is likely responsible for a dark lane in a large HII region by the dust extinction. The N159W clump is associated with embedded clusters mainly toward the eastern edge of the clump only. These clusters show offsets of 20"-40" from the 12CO J=4-3 peak and are probably responsible for heating indicated by the derived high temperature. The N159W clump exhibits no sign of star formation toward the 12CO J=4-3 peak position and its western region. We suggest that the N159W peak represents a pre-star-cluster core of ~105M_sol which deserves further detailed studies. Note that recent star formation took place between N159W and N159E as indicated by several star clusters and HII regions, while the natal molecular gas toward the stars have already been dissipated by the ionization and stellar winds of the OB stars. The N159S clump shows little sign of star formation as is consistent with the lower temperature and somewhat lower density. The N159S clump is also a candidate for future star formation.

Understanding the process of star formation in low metallicity systems is one of the key studies in the early stages of galaxy evolution. The Magellanic Clouds, being the nearest examples of low metallicity systems, allow us to study in detail their star forming regions. As a consequence of their proximity we can resolve the molecular clouds and the regions of star formation individually. Therefore we can increase our knowledge of the interaction of young luminous stars with their environment. We will present results of multiwavelenghts studies of LMC and SMC massive star forming regions, which includes properties of the cold molecular gas, the embedded young population associated with molecular clouds, and the interaction of newly born stars with the surrounding interstellar medium, based on ASTE and APEX submillimeter observations complemented high sensitivity NIR groud based observations and Spitzer results.

This work aims at investigating the molecular gas component in the vicinity of two young stellar object (YSO) candidates identified at the border of the HII region G034.8-0.7 that is evolving within a molecular cloud shocked by the SNR W44. The purpose is to explore signatures of star forming activity in this complex region. We performed a near and mid infrared study towards the border of the HII region G034.8-0.7 and observed a 90" X 90" region near 18h 56m 48s, +01d 18' 45" (J2000) using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3--2, 13CO J=3--2, HCO+ J=4--3 and CS J=7--6 lines with an angular resolution of 22". Based on the infrared study we propose that the source 2MASS 18564827+0118471 (IR1 in this work) is a YSO candidate. We discovered a bipolar 12CO outflow in the direction of the line of sight and a HCO+ clump towards IR1, confirming that it is a YSO. From the detection of the CS J=7--6 line we infer the presence of high density (>10^7 cm^-3) and warm (>60 K) gas towards IR1, probably belonging to the protostellar envelope where the YSO is forming. We investigated the possible genetic connection of IR1 with the SNR and the HII region. By comparing the dynamical time of the outflows and the age of the SNR W44, we conclude that the possibility of the SNR has triggered the formation of IR1 is unlikely. On the other hand, we suggest that the expansion of the HII region G034.8-0.7 is responsible for the formation of IR1 through the "collect and collapse" process., 19 pages, 14 figures. Figures degraded to reduce file size. Accepted 06/02/2009 for publication in A&A

We present the first high-spatial-resolution nearinfrared (NIR) imaging of NGC604, obtained with the NICMOS camera onboard the Hubble Space Telescope (HST). These NICMOS broad-band images reveal new NIR point sources, clusters, and diffuse structures. We find an excellent spatial correlation between the 8.4 GHz radio continuum and the 2.2 µm nebular emission. Moreover, massive young stellar object candidates appear aligned with these radio peaks, reinforcing the idea that those areas are star-forming regions. Three different scaled OB associations are recognized in the NICMOS images. The brightest NIR sources in our images have properties that suggest that they are red supergiant stars, of which one was previously known. This preliminary analysis of the NICMOS images shows the complexity of the stellar content of the NGC604 nebula., Facultad de Ciencias Astronómicas y Geofísicas, Instituto de Astrofísica de La Plata

Aims. We present a study of the ionized, neutral atomic, and molecular gas associated with the ring nebula RCW78 around the WR star HD117688 (=WR55) with the aim of analyzing the distribution of the associated gas and investigating its energetics. Methods. We base our study on 12CO(1-0) and 12CO(2-1) observations of the brightest section of the nebula carried out with the SEST telescope with angular resolutions of 45'' and 22'', respectively; and on complementary 12CO(1-0) data of a larger area obtained with the NANTEN telescope with an angular resolution of 2. ′ 7, Hi 21-cm line data taken from the ATCA survey, IRAS HIRES data, and radio continuum data at 4.85 GHz from the Parkes survey. Results. We report the detection of molecular gas having velocities in the range -56 to -33 kms -1 associated with the western region of RCW78. A few patches of molecular gas possibly linked to the eastern faint section are detected. The CO emission appears concentrated in a region of 23′ ×18′ in size, with a total molecular mass of (1.3 ±0.5) ×105 M ⊙, mainly connected to the western section. The analysis of the neutral atomic gas distribution reveals the Hi envelope of the molecular cloud, while the radio continuum emission shows a ring-like structure, which is the radio counterpart of the optical nebula. The gas distribution is compatible with the western section of RCW78 having originated in the photodissociation and ionization of the molecular gas by the UV photons of the WN7 star HD117688, and with the action of the stellar winds of the WR star on the surrounding gas. In this scenario, the interstellar bubble expanded more easily towards the east than towards the west due to the lack of dense molecular gas in the eastern section. The proposed scenario also explains the off center location of WR55. A number of infrared point sources classified as YSO candidates showed that star formation activity is present in the molecular gas linked to the nebula. The possibility that the expansion of the bubble triggered star formation in this region cannot be discarded., Facultad de Ciencias Astronómicas y Geofísicas, Instituto Argentino de Radioastronomía

To understand the impact of low metallicities on giant molecular cloud (GMC) structure, we compare far infrared dust emission, CO emission, and dynamics in the star-forming complex N83 in the Wing of the Small Magellanic Cloud. Dust emission (measured by Spitzer as part of the S3MC and SAGE-SMC surveys) probes the total gas column independent of molecular line emission and traces shielding from photodissociating radiation. We calibrate a method to estimate the dust column using only the high-resolution Spitzer data and verify that dust traces the ISM in the HI-dominated region around N83. This allows us to resolve the relative structures of H2, dust, and CO within a giant molecular cloud complex, one of the first times such a measurement has been made in a low-metallicity galaxy. Our results support the hypothesis that CO is photodissociated while H2 self-shields in the outer parts of low-metallicity GMCs, so that dust/self shielding is the primary factor determining the distribution of CO emission. Four pieces of evidence support this view. First, the CO-to-H2 conversion factor averaged over the whole cloud is very high 4-11 \times 10^21 cm^-2/(K km/s), or 20-55 times the Galactic value. Second, the CO-to-H2 conversion factor varies across the complex, with its lowest (most nearly Galactic) values near the CO peaks. Third, bright CO emission is largely confined to regions of relatively high line-of-sight extinction, A_V >~ 2 mag, in agreement with PDR models and Galactic observations. Fourth, a simple model in which CO emerges from a smaller sphere nested inside a larger cloud can roughly relate the H2 masses measured from CO kinematics and dust., 17 pages, 10 figures (including appendix), accepted for publication in the Astrophysical Journal

The central 2° × 2° area of the Small Magellanic Cloud (SMC) has been fully surveyed in the J = 1 → 0 rotational transition of 12 CO at an angular resolution of 8.8'. Most of the emission arises from two large complexes, located in the southwest and northeast regions of the Bar, closely associated with the most intense H I emission from the SMC. Five individual molecular clouds are identified; their peak antenna temperatures are very weak, ∼ 0.035 K. It is suggested that for the SMC, the conversion factor to derive the column density of molecular hydrogen from the velocity-integrated CO line emission is 6 × 10 21 (K km cm 2 ) -1 s, which is about 20 times higher than the value adopted for our Galaxy.

We present the results of observations of the 12CO(1-0) emission line from the Small Magellanic Cloud done with the 15m SEST telescope. We have fully mapped two areas in the SW region of the SMC bar and have identified several molecular clouds. Molecular clouds in the SMC show different properties than that of Galactic molecular clouds. They follow the same linewidth-size relation (ΔV R1/2) as Galactic clouds for a large range of radii, but they are undcrluminous in CO. At the smallest scales we can resolve (10 pc), the SMC CO clouds are less luminouds in CO by a factor of 2, while at large scales they are less luminous by a factor of 20. The physical properties derived from two clouds where 12CO(2-1), 13C0(1-0), and 13C0(2-1) observations were done indicate that the CO clouds are clumpy, with a higher kinetic temperature and a smaller filling factor than that of Galactic CO clouds. These properties can be explained as a consequence of a higher photodissociation rate of CO. Assuming virial equilibrium for the CO structures we derive a preliminary estime of the conversion factor to derive total mass of gas from the CO luminosity. This factor is larger that the canonical value adopted for our Galaxy and depends on the size of the molecular cloud.

Star formation at earlier cosmological times takes place in an interstellar medium with low metallicity. The Large Magellanic Cloud (LMC) is ideally suited to study star formation in such an environment. The physical and chemical state of the ISM in a star forming environment can be constrained by observations of submm and FIR spectral lines of the main carbon carrying species, CO, CI and CII, which originate in the surface layers of molecular clouds illuminated by the UV radiation of the newly formed, young stars. We present high-angular resolution sub-millimeter observations in the N159W region in the LMC obtained with the NANTEN2 telescope of the 12CO J = 4-3, J = 7-6, and 13CO J = 4-3 rotational and [CI] 3P1-3P0 and 3P2-3P1 fine-structure transitions. The 13CO J =4-3 and [CI] 3P2-3P1 transitions are detected for the first time in the LMC. We derive the physical and chemical properties of the low-metallicity molecular gas using an escape probability code and a self-consistent solution of the chemistry and thermal balance of the gas in the framework of a clumpy cloud PDR model. The separate excitation analysis of the submm CO lines and the carbon fine structure lines shows that the emitting gas in the N159W region has temperatures of about 80 K and densities of about 10^4 cm^-3. The estimated C to CO abundance ratio close to unity is substantially higher than in dense massive star-forming regions in the Milky Way. The analysis of all observed lines together, including the [CII] line intensity reported in the literature, in the context of a clumpy cloud PDR model constrains the UV intensity to about \chi ~220 and an average density of the clump ensemble of about 10^5 cm^-3, thus confirming the presence of high density material in the LMC N159W region., Comment: Accepted for publication to A&A. 14 pages, 7 figures (3 in Color), 3 tables. A version with high resolution figures available at http://www.astro.uni-bonn.de/~jopineda/pega/n159w_paper.pdf

This paper reports molecular observations towards the Bright Eastern Knot (BEK) in the SNR Puppis A, a feature where radio and X-ray studies suggest that the shock front is interacting with a dense molecular clump. We performed high-resolution millimetric observations towards the BEK of Puppis A using the SEST telescope in the 12CO J=1-0 and 2-1 lines (beams of 45" and 23" respectively). More extended, lower angular resolution 12CO J=1-0 observations taken from NANTEN archival data were also analyzed to obtain a complete picture. In the velocity range near 16 km/s, the Puppis A systemic velocity, our study revealed two important properties: (i) no dense molecular gas is detected immediately adjacent to the eastern border of the BEK and (ii) the molecular clump detected very close to the radiocontinuum maximum is probably located in the foreground along the line of sight and has not yet been reached by the SNR shock front. We propose two possible scenarios to explain the absence of molecular emission eastwards of the BEK border of Puppis A. Either the shock front has completely engulfed and destroyed a molecular clump or the shock front is interacting with part of a larger cloud and we do not detect CO emission immediately beyond it because the molecules have been dissociated by photodissociation and by reactions with photoionized material due to the radiative precursor., Comment: 10 pages, 7 figures. Accepted for publication in A&A

Using the APEX sub-millimeter telescope we have investigated the 12CO(3-2) emission in five face-on nearby barred spiral galaxies, where three of them are high surface brightness galaxies (HSBs) lying at the Freeman limit, and two are low surface brightness galaxies (LSBs). We have positive detections for two of three HSB spirals and non-detections for the LSBs. For the galaxies with positive detection (NGC0521 and PGC070519), the emission is confined to their bulges, with velocity dispersions of ~90 and ~73 km/s and integrated intensities of 1.20 and 0.76 K/km/s, respectively. For the non-detections, the estimated upper limit for the integrated intensity is ~0.54 K/km/s. With these figures we estimate the H2 masses as well as the atomic-to-molecular mass ratios. Although all the galaxies are barred, we observe 12CO(3-2) emission only for galaxies with prominent bars. We speculate that bars could dynamically favor the 12CO(3-2) emission, as a second parameter after surface brightness. Therefore, secular evolution could play a major role in boosting collisional transitions of molecular gas, such as 12CO(3-2), especially in LSBs., Comment: 11 pages, 1 figure, ApJ Letters, in press (vol 677)

Molecular gas in galaxies is the primary fuel of star formation but the exact amount of molecular gas remains unknown since H_2 is not observed directly in cold interstellar regions. CO observations have been so far the best way to trace molecular gas in external galaxies, but in low metallicity environments the gas mass deduced could be largely underestimated due to enhanced photodissociation of CO. In this context, using millimeter dust emission as a dense gas tracer could unveil large H_2 enveloppes in molecular clouds. Mass estimates from millimeter dust emission are compared to virial masses in two giant molecular clouds samples: the local clouds in our Galaxy, and equivalents in the Small Magellanic Cloud. In our Galaxy, virial masses are systematically larger than mass estimates from millimeter emission, confirming previous studies. This is not the case for SMC clouds: molecular gas masses deduced from millimeter observations are systematically higher than the virial masses from CO observations. We show that an additional magnetic field support of the SMC clouds could explain the difference observed.

The second survey of the molecular clouds in 12CO (J = 1-0) was carried out in the Large Magellanic Cloud by NANTEN. The sensitivity of this survey is twice as high as that of the previous NANTEN survey, leading to a detection of molecular clouds with M_CO > 2 x 10^4 M_sun. We identified 272 molecular clouds, 230 of which are detected at three or more observed positions. We derived the physical properties, such as size, line width, virial mass, of the 164 GMCs which have an extent more than the beam size of NANTEN in both the major and minor axes. The CO luminosity and virial mass of the clouds show a good correlation of M_VIR propto L_CO^{1.1 +- 0.1} with a Spearman rank correlation of 0.8 suggesting that the clouds are in nearly virial equilibrium. Assuming the clouds are in virial equilibrium, we derived an X_CO-factor to be ~ 7 x 10^20 cm^-2 (K km s^-1)^-1. The mass spectrum of the clouds is fitted well by a power law of N_cloud(>M_CO) proportional to M_CO^{-0.75 +- 0.06} above the completeness limit of 5 x 10^4 M_sun. The slope of the mass spectrum becomes steeper if we fit only the massive clouds; e.g., N_cloud (>M_CO) is proportional to M_CO^{-1.2 +- 0.2} for M_CO > 3 x 10^5 M_sun., 54 pages in total, 18 figures (21 files) and 4 tables, to appear in Astrophysical Journal Supplement Series. A full color version with higher resolution figures is available at http://www.a.phys.nagoya-u.ac.jp/~kawamura/research/NANTEN_LMC_1_preprint_highres.pdf

The study of the Large Magellanic Cloud (LMC) is important to understand the formation process of massive stellar clusters. N159 is one of the most active cluster forming regions in the LMC. Bolatto et al. [2] observed sub-mm CO and C i lines in this region and found CO(J=4–3) the emission peak at N159W. This observation didn’t have enough resolution to reveal the high temperature molecular cloud structure. So we observe with the NANTEN2 telescope to improve the image resolution.

tetsu@astro1.sci.hokudai.ac.jp 2 Department of Astrophysics, Nagoya University, Japan 3 National Astronomical Observatory of Japan, Japan 4 Research Center for the Early Universe and Department of Physics, University of Tokyo, Japan 5 National Radio Astronomy Observatory, USA 6 Department of Astronomy, MC 221, University of Illinois, USA 7 Australia Telescope National Facility, CSIRO, Australia 8 Radioastronomisches Institut der Universitat Bonn, Germany 9 Center for Supercomputing and Astrophysics, Swinburne University of Technology, Germany 10 School of Physics, University of Western Australia, Australia 11 Solar-Terrestrial Environment Laboratory, Nagoya University, Japan 12 Departament de Astronomia, Universidad de Chile, Chile 13 Hartebeesthoek Radio Astronomy Observatory, South Africa 14 Onsala Space Observatory, Sweden 15 European Southern Observatory 16 Astronomy & Space Science Department, Sejong University, Korea

We have carried out sub-mm 12CO(J=3-2) observations of 6 giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC) with the ASTE 10m sub-mm telescope at a spatial resolution of 5 pc and very high sensitivity. We have identified 32 molecular clumps in the GMCs and revealed significant details of the warm and dense molecular gas with n(H2) $\sim$ 10$^{3-5}$ cm$^{-3}$ and Tkin $\sim$ 60 K. These data are combined with 12CO(J=1-0) and 13CO(J=1-0) results and compared with LVG calculations. We found that the ratio of 12CO(J=3-2) to 12CO(J=1-0) emission is sensitive to and is well correlated with the local Halpha flux. We interpret that differences of clump propeties represent an evolutionary sequence of GMCs in terms of density increase leading to star formation.Type I and II GMCs (starless GMCs and GMCs with HII regions only, respectively) are at the young phase of star formation where density does not yet become high enough to show active star formation and Type III GMCs (GMCs with HII regions and young star clusters) represents the later phase where the average density is increased and the GMCs are forming massive stars. The high kinetic temperature correlated with \Halpha flux suggests that FUV heating is dominant in the molecular gas of the LMC., Comment: 74 pages, including 41 figures, accepted for publication in ApJS

In a previous paper we have investigated the molecular environment towards the eastern border of the SNR G18.8+0.3. Continuing with the study of the surroundings of this SNR, in this work we focus on its southern border, which in the radio continuum emission shows a very peculiar morphology with a corrugated corner and a very flattened southern flank. We observed two regions towards the south of SNR G18.8+0.3 using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3-2. One of these regions was also surveyed in 13CO and C18O J=3-2. The angular and spectral resolution of these observations were 22", and 0.11 km/s. We compared the CO emission to 20 cm radio continuum maps obtain as part of the Multi-Array Galactic Plane Imaging Survey (MAGPIS) and 870 um dust emission extracted from the APEX Telescope Large Area Survey of the Galaxy. We discovered a molecular feature with a good morphological correspondence with the SNR's southernmost corner. In particular, there are indentations in the radio continuum map that are complemented by protrusions in the molecular CO image, strongly suggesting that the SNR shock is interacting with a molecular cloud. Towards this region we found that the 12CO peak is not correlated with the observed 13CO peaks, which are likely related to a nearby \hii~region. Regarding the most flattened border of SNR G18.8+0.3, where an interaction of the SNR with dense material was previously suggested, our 12CO J=3-2 map show no obvious indication that this is occurring., Comment: accepted for publication in A&A, July 2015

Augmented Reality systems have recently become widely used. This is due to the new open source libraries that have emerged for fast application development. In this paper we address one of the most relevant problems in this type of systems, oscillation in the camera pose estimates. We study the oscillation of a system developed using the ARToolkit library. We apply both average and Kalman filters to stabilize the estimates. Using filter substantially reduces oscillation, thus improving the system’s usability.

We present J=1-0 and J=2-1 12CO maps of several star-forming regions in both the Large and the Small Magellanic Cloud, and briefly discuss their structure. Many of the detected molecular clouds are relatively isolated and quite small with dimensions of typically 20 pc. Some larger complexes have been detected, but in all cases the extent of the molecular clouds sampled by CO emission is significantly less than the extent of the ionized gas of the star-formation region. Very little diffuse extended CO emission was seen; diffuse CO in between or surrounding the detected discrete clouds is either very weak or absent. The majority of all LMC lines of sight detected in 13CO has an isotopic emission ratio I(12CO)/I(13CO) of about 10, i.e. twice higher than found in Galactic star-forming complexes. At the lowest 12CO intensities, the spread of isotopic emission ratios rapidly increases, low ratios representing relatively dense and cold molecular gas and high ratios marking CO photo-dissociation at cloud edges., Comment: 13 pages, accepted by Astronomy and Astrophysics

CCD infrared ( JHK s ) photometry was performed on a sample of 10 elliptical and 2 lenticular galaxies. Isophotal parameters, brightness profiles, integrated colors and color gradients are presented. Color gradients found are very weak, showing bluer colors towards the outer regions. The colors of the sample galaxies are compatible with stellar populations like those found in metal-rich clusters of the Galaxy; objects NGC 7192, NGC 7562 and NGC 7619 are compatible with less metal-rich populations. The brightness profile of most galaxies is well described by the $r^{1/4}$ law. The profiles of NGC 1600 and NGC 720 are described by Sersic's law with $n\sim{1.5}$ and $n\sim{1.8}$ respectively. The infrared effective radius of the objects studied is typically one half of its counterpart in the B band, which can be an indication that the stellar population that dominates the infrared emission is more concentrated in the central regions. We show that the sample satisfies the Fundamental Plane relation of elliptical galaxies in the infrared, with an rms scatter of 0.20 for J and H and 0.23 for K s .

We report observations of the CO(1!0), CO(2!1) and 13 CO(1!0) line emission from the giant molec- ular complex No. 37 of the Large Magellanic Cloud, made with linear resolutions between 6 and 12 pc. The obser- vations were undertaken with the Swedish-ESO Submillimetre Telescope (SEST) as part of the Key Programme: CO in the Magellanic Clouds. We nd that the CO(1!0) emission arises from six large, distinct, molecular clouds, with CO luminosities in the range 1 10 4 to 5 10 4 Kk m s 1 pc 2 and sizes between 22 and 38 pc, and seven smaller clumps, with CO luminosities in the range between 7 10 2 and 2 10 3 Kk m s 1 pc 2 . The opacities in the CO(1!0) line at the peak position of the large clouds are remarkably smaller than those derived for Galactic molecular clouds. Relationships between line width, size and CO luminosities are discussed. The total CO lumi- nosity of the complex determined from the SEST observations, of 1:810 5 Kk m s 1 pc 2 , is in excellent agreement with that determined from the low spatial resolution (140 pc) observations of Cohen et al. On the other hand, the total mass of molecular gas in the complex derived from the SEST observations, assuming that the individual clouds are virialized, is 2:4 10 6 M, which is a factor of 6 lower than that estimated by Cohen et al. under the same assumption. We conclude that the value of the velocity integrated CO emission to H2 column density conversion factor in the LMC determined from low angular resolution observations has been overestimated by a factor of 3. We derive a conversion factor for clouds in Complex-37 of 6 10 20 cm 2 K 1 km 1 s, which is similar to that for clouds in the outer Galaxy.

We present maps and a catalogue containing the J=1-0 12CO parameters of 29 individual molecular clouds in the second-brightest LMC star formation complex, N11. In the southwestern part of N11, molecular clouds occur in a ring or shell surrounding the major OB star association LH9. In the northeastern part, a chain of molecular clouds delineates the rim of one of the so-called supergiant shells in the LMC. The well-defined clouds have dimensions close to those of the survey beam (diameters of 25 pc or less). Some of the clouds were also observed in J=2-1 12CO, and in the lower two transitions of 13CO. Clouds mapped with a twice higher angular resolution in J=2-1 12CO show substructure with dimensions once again comparable to those of the mapping beam. The few clouds for which we could model physical parameters have fairly warm (T(kin) = 60 - 150 K) and moderately dense (n(H2) = 3000 cm-3) gas. The northeastern chain of CO clouds, although lacking in diffuse intercloud emission, is characteristic of the more quiescent regions of the LMC and appears to have been subject to relatively little photo-processing. The clouds forming part of the southwestern shell or ring, however, are almost devoid of diffuse intercloud emission and also exhibit other characteristics of an extreme photon-dominated region (PDR)., 14 pages; accepted for publication in A&A

N113 is an HII region located in the central part of the Large Magellanic Cloud (LMC) with an associated molecular cloud very rich in molecular species. Most of the previously observed molecular lines cover the frequency range 85-270 GHz. Thus, a survey and study of lines at the 345 GHz window is required in order to have a more complete understanding of the chemistry and excitation conditions of the region. We mapped a region of 2.5' x 2.5' centered at N113 using the Atacama Submillimeter Telescope Experiment in the 13CO J=3-2 line with an angular and spectral resolution of 22" and 0.11 km/s, respectively. In addition, we observed 16 molecular lines as single pointings towards its center. For the molecular cloud associated with N113, from the 13CO J=3-2 map we estimate LTE and virial masses of about 1x10^4 and 4.5x10^4 M_sun, respectively. Additionally, from the dust continuum emission at 500 micron we obtain a mass of gas of 7x10^3 M_sun. Towards the cloud center we detected emission from: 12CO, 13CO, C18O (3-2), HCN, HNC, HCO+, C2H (4-3), and CS (7-6); being the first reported detection of HCN, HNC, and C2H (4-3) lines from this region. The CS (7-6) which was previously tentatively detected is confirmed in this study. By analyzing the HCN, HNC, and C2H, we suggest that their emission may arise from a photodissociation region (PDR). Moreover, we suggest that the chemistry involving the C2H in N113 can be similar to that in Galactic PDRs. Using the HCN J=4-3, J=3-2, and J=1-0 lines in a RADEX analysis we conclude that we are observing very high density gas, between some 10^5 and 10^7 cm-3., Comment: accepted for publication in A&A, September 9, 2014

We present the first results from a new 12 CO (J = 1–0) survey of the Small Magellanic Cloud (SMC) with the NANTEN millimeter-wave telescope. The survey covered the northeast and southwest regions of the main Bar, and the H II regions N 84, N 88 in the Wing at a linear resolution of ∼50pc. Twenty-one giant molecular clouds (GMCs), whose masses are ∼ 10 4 –10 6 M� , were identified. Significant CO emission, T ∗ R ∼ 0.36K, was first detected toward the N 84 region in the Wing, which is comparable to those of the prominent CO clouds associated with infrared sources LIRS 36, LIRS 49 in the Bar. The GMCs exhibit a good spatial correlation with the HII regions and young clusters, indicating that cluster formation is on-going in these GMCs. On the other hand, they show little correlation with older clusters or with supernova remnants, suggesting rapid dissipation of CO.