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We present polarization observations of two Galactic plane fields centered on Galactic coordinates (l,b)=(0 deg,0 deg) and (329 deg, 0 deg) at Q- (43 GHz) and W-band (95 GHz), covering between 301 and 539 square degrees depending on frequency and field. These measurements were made with the QUIET instrument between 2008 October and 2010 December, and include a total of 1263 hours of observations. The resulting maps represent the deepest large-area Galactic polarization observations published to date at the relevant frequencies with instrumental rms noise varying between 1.8 and 2.8 uK deg, 2.3-6 times deeper than corresponding WMAP and Planck maps. The angular resolution is 27.3' and 12.8' FWHM at Q- and W-band, respectively. We find excellent agreement between the QUIET and WMAP maps over the entire fields, and no compelling evidence for significant residual instrumental systematic errors in either experiment, whereas the Planck 44 GHz map deviates from these in a manner consistent with reported systematic uncertainties for this channel. We combine QUIET and WMAP data to compute inverse-variance-weighted average maps, effectively retaining small angular scales from QUIET and large angular scales from WMAP. From these combined maps, we derive constraints on several important astrophysical quantities, including a robust detection of polarized synchrotron spectral index steepening of ~0.2 off the plane, as well as the Faraday rotation measure toward the Galactic center (RM=-4000 +/- 200 rad m^-2), all of which are consistent with previously published results. Both the raw QUIET and the co-added QUIET+WMAP maps are made publicly available together with all necessary ancillary information., Comment: 22 pages, 18 figures; accepted for publication in ApJ; data are available on Lambda (http://lambda.gsfc.nasa.gov)

Context: Infrared dark clouds are the coldest and densest portions of giant molecular clouds. The most massive ones represent some of the most likely birthplaces for the next generation of massive stars in the Milky Way. Because a strong mid-IR background is needed to make them appear in absorption, they are usually assumed to be nearby. Aims: We use THz absorption spectroscopy to solve the distance ambiguity associated with kinematic distances for the IR-dark clouds in the TOP100 ATLASGAL sample, a flux-limited selection of massive clumps in different evolutionary phases of star formation. Methods: The para-H2O ground state transition at 1113.343 GHz, observed with Herschel/HIFI, was used to investigate the occurrence of foreground absorption along the line of sight directly towards infrared-dark clouds. Additional consistency checks were performed using MALT90 and HiGAL archival data and targeted Mopra and APEX spectroscopic observations. Results: We report the first discovery of five IRDCs in the TOP100 lying conclusively at the far kinematic distance, showing that the mere presence of low-contrast mid-IR absorption is not sufficient to unequivocally resolve the near/far ambiguity in favour of the former. All IRDCs are massive and actively forming high-mass stars; four of them also show infall signatures. Conclusions: We give a first estimate of the fraction of dark sources at the far distance (~11% in the TOP100) and describe their appearance and properties. The assumption that all dark clouds lie at the near distance may lead, in some cases, to underestimating masses, sizes, and luminosities, possibly causing clouds to be missed that will form very massive stars and clusters., Comment: Accepted for publication in A&A Letters; 4 pages, 3 figures, 6 pages of online material

The formation of high mass stars and clusters occurs in giant molecular clouds. Objects in evolved stages of massive star formation such as protostars, hot molecular cores, and ultracompact HII regions have been studied in more detail than earlier, colder objects. With this in mind, the APEX Telescope Large Area Survey of the whole inner Galactic plane at 870 micron (ATLASGAL) has been carried out to provide a global view of cold dust and star formation at submillimetre wavelengths. To derive kinematic distances to a large sample of ATLASGAL clumps we divided them into groups of sources, which are located close together, mostly within a radius of 2 pc, and have velocities in a similar range with a median velocity dispersion of ~ 1 km/s. Using NH3, N2H+ and CS velocities we calculate near and far kinematic distances to 296 groups of ATLASGAL sources in the first quadrant and 393 groups in the fourth quadrant. We analyse HI self-absorption and HI absorption to resolve the kinematic distance ambiguity. We obtain a scale height of ~ 28+/-2 pc and displacement below the Galactic midplane of ~ -7+/-1 pc. Within distances from 2 to 18 kpc ATLASGAL clumps have a broad range of gas masses with a median of 1050 solar masses and a wide distribution of radii with a median of 0.4 pc. Their distribution in galactocentric radii is correlated with spiral arms. Using a statistically significant ATLASGAL sample we derive a power-law exponent of -2.2+/-0.1 of the clump mass function. This is consistent with the slope derived for clusters and with that of the stellar initial mass function. Examining the power-law index for different galactocentric distances and various source samples shows that it is independent of environment and evolutionary phase. Fitting the mass-size relationship by a power law gives a slope of 1.76+/-0.01 for cold sources such as IRDCs and warm clumps associated with HII regions., Comment: Figure 2 has a reduced file size, please see A&A version of this paper for high resolution graphics

We present first results of neutral carbon ([CI], 3P1 - 3P0 at 492 GHz) and carbon monoxide (13CO, J = 1 - 0) mapping in the Vela Molecular Ridge cloud C (VMR-C) and G333 giant molecular cloud complexes with the NANTEN2 and Mopra telescopes. For the four regions mapped in this work, we find that [CI] has very similar spectral emission profiles to 13CO, with comparable line widths. We find that [CI] has opacity of 0.1 - 1.3 across the mapped region while the [CI]/13CO peak brightness temperature ratio is between 0.2 to 0.8. The [CI] column density is an order of magnitude lower than that of 13CO. The H2 column density derived from [CI] is comparable to values obtained from 12CO. Our maps show CI is preferentially detected in gas with low temperatures (below 20 K), which possibly explains the comparable H2 column density calculated from both tracers (both CI and 12CO underestimate column density), as a significant amount of the CI in the warmer gas is likely in the higher energy state transition ([CI], 3P2 - 3P1 at 810 GHz), and thus it is likely that observations of both the above [CI] transitions are needed in order to recover the total H2 column density., Comment: accepted for publication in ApJ Letters

The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) is the largest and most sensitive systematic survey of the inner Galactic plane in the submillimetre wavelength regime. The observations were carried out with the Large APEX Bolometer Camera (LABOCA), an array of 295 bolometers observing at 870\,$\mu$m (345 GHz). Aim: In this research note we present the compact source catalogue for the 280\degr\ $ <\ell <$ 330\degr\ and 21\degr\ $ <\ell <$ 60\degr\ regions of this survey. Method: The construction of this catalogue was made with the source extraction routine \sex\ using the same input parameters and procedures used to analyse the inner Galaxy region presented in an earlier publication (i.e., 330\degr\ $ <\ell <$ 21\degr). Results: We have identified 3523 compact sources and present a catalogue of their properties. When combined with the regions already published this provides a comprehensive and unbiased database of ~10163 massive, dense clumps located across the inner Galaxy., Comment: Submitted to A&A. Consists of 5 pages, 4 figures and one table. Only a small sample of Table 1 is given and the full table will be made available through CDS

By matching infrared-selected, massive young stellar objects (MYSOs) and compact HII regions in the RMS survey to massive clumps found in the submillimetre ATLASGAL survey, we have identified ~1000 embedded young massive stars between 280\degr < $\ell$ < 350\degr and 10degr < $\ell$ < 60\degr with |b|<1.5degr. Combined with an existing sample of radio-selected methanol masers and compact HII regions, the result is a catalogue of ~1700 massive stars embedded within ~1300 clumps located across the inner Galaxy, containing three observationally distinct subsamples, methanol-maser, MYSO and HII-region associations, covering the most important tracers of massive star formation, thought to represent key stages of evolution. We find that massive star formation is strongly correlated with the regions of highest column density in spherical, centrally condensed clumps. We find no significant differences between the three samples in clump structure or the relative location of the embedded stars, which suggests that the structure of a clump is set before the onset of star formation, and changes little as the embedded object evolves towards the main sequence. There is a strong linear correlation between clump mass and bolometric luminosity, with the most massive stars forming in the most massive clumps. We find that the MYSO and HII-region subsamples are likely to cover a similar range of evolutionary stages and that the majority are near the end of their main accretion phase. We find few infrared-bright MYSOs associated with the most massive clumps, probably due to very short pre-main sequence lifetimes in the most luminous sources., Comment: Accepted for publication in MNRAS: 33 pages, 24 figures and 9 tables. Full versions of Fig. 3 and Tables 1, 3, 6 and 7 will only be available in electronic form via CDS. The resolution of Figs. 1, 5, 7 and 21 have been reduced but a higher resolution version of the paper is available upon request

The Columbia - U. de Chile CO Survey of the Southern Milky Way is used for separating the CO(1-0) emission of the fourth Galactic quadrant within the solar circle into its dominant components, giant molecular clouds (GMCs). After the subtraction of an axisymmetric model of the CO background emission in the inner Southern Galaxy, 92 GMCs are identified, and for 87 of them the two-fold distance ambiguity is solved. Their total molecular mass is M(H2) = 1.14 +/- 0.05 x 10^8 Msolar accounting for around 40% of the molecular mass estimated from an axisymmetric analysis of the H2 volume density in the Galactic disk (Bronfman et al. 1988b) M(H2) disk = 3.03 x 10^8 Msolar. The large scale spiral structure in the Southern Galaxy, within the solar circle, is traced by the GMCs in our catalog; 3 spiral arm segments: the Centaurus, Norma, and 3-kpc expanding arm are analyzed. After fitting a logarithmic spiral arm model to the arms, tangent directions at 310{\deg}, 330{\deg}, and 338{\deg}, respectively, are found, consistent with previous values from the literature. A complete CS(2-1) survey toward IRAS point-like sources with FIR colors characteristic of UC HII regions is used to estimate the massive star formation rate per unit H2 mass (MSFR), and the massive star formation efficiency for GMCs. The average MSFR for GMCs is 0.41 +/- 0.06 Lsolar/Msolar, and for the most massive clouds in the Norma arm it is 0.58 +/- 0.09 Lsolar/Msolar. Massive star formation efficiencies of GMCs are on average 3% of their available molecular mass.

We are presenting here a follow-up study of the molecular gas and dust in the environs of the star forming region NGC 3503. This study aims at dealing with the interaction of NGC 3503 with its parental molecular cloud, and also with the star formation in the region. To analyze the molecular gas we use CO(2-1), 13CO(2-1), C18O(2-1), and HCN(3-2) line data obtained with the APEX telescope. To study the distribution of the dust, we make use of images at 870 microns from the ATLASGAL survey and IRAC-GLIMPSE archival images. We use public 2MASS and WISE data to search for candidate YSOs in the region. The new APEX observations allowed the substructure of the molecular gas in the velocity range from -28 to -23 km/s to be imaged in detail. The morphology of the molecular gas close to the nebula, the location of the PDR, and the shape of radio continuum emission suggest that the ionized gas is expanding against its parental cloud, and confirm the "champagne flow" scenario. We have identified several molecular clumps and determined some of their physical and dynamical properties. We have compared the physical properties of the clumps to investigate how the molecular gas has been affected by the HII region. Clumps adjacent to the ionization fronts of NGC 3503 and/or the bright rimmed cloud SFO62 have been heated and compressed by the ionized gas, but their line width is not different to those that are too distant to the ionization fronts. We identified several candidate YSOs in the region. Their spatial distribution suggests that stellar formation might have been boosted by the expansion of the nebula. We discard the "collect and collapse" scenario and propose alternative mechanisms such as radiatively driven implosion on pre-existing molecular clumps or small-scale Jeans gravitational instabilities., Comment: 18 pages, 13 figures. Accepted for publication in A&A

The formation processes and the evolutionary stages of high-mass stars are poorly understood compared to low-mass stars. Large-scale surveys are needed to provide an unbiased census of high column density sites which can potentially host precursors to high-mass stars. Here we use the ATLASGAL survey covering 420 sq. degree of the Galactic plane at 870 $\mu$m; and use the MRE-GLC method to identify the population of embedded sources throughout the inner Galaxy. We identify in total 10861 compact sub-millimeter sources with fluxes above 5 sigma. Completeness tests show that our catalogue is 97% complete above 5 sigma and >99% complete above 7$\sigma$. We correlate this sample with mid-infrared point source catalogues (MSX at 21.3 $\mu$m and WISE at 22 $\mu$m) and determine a lower limit of ~33% that are associated with embedded protostellar objects. We note that the proportion of clumps associated with mid-infrared sources increases with increasing flux density, achieving a rather constant fraction of ~75% of all clumps with fluxes over 5 Jy/beam being associated with star-formation. Examining the source counts as a function of Galactic longitude we are able to identify the most prominent star forming regions in the Galaxy. From the fraction of the likely massive quiescent clumps (~25%) we estimate a formation time-scale of ~7.5+/-2.5 $\times$ 10$^4$yr for the deeply embedded phase before the emergence of luminous YSOs. Such a short duration for the formation of high-mass stars in massive clumps clearly proves that the earliest phases have to be dynamic with supersonic motions., Comment: accepted for publication by A&A

A fast moving infrared excess source (G2) which is widely interpreted as a core-less gas and dust cloud approaches Sagittarius A* (SgrA*) on a presumably elliptical orbit. VLT K_s-band and Keck K'-band data result in clear continuum identifications and proper motions of this about 19m Dusty S-cluster Object (DSO). In 2002-2007 it is confused with the star S63, but free of confusion again since 2007. Its near-infrared (NIR) colors and a comparison to other sources in the field speak in favor of the DSO being an IR excess star with photospheric continuum emission at 2 microns than a core-less gas and dust cloud. We also find very compact L'-band emission ($<$0.1'') contrasted by the reported extended (0.03'' up to about 0.2'' for the tail) Brgamma emission. The presence of a star will change the expected accretion phenomena, since a stellar Roche lobe may retain a fraction of the material during and after the peri-bothron passage., Comment: 4 pages, 2 figures, Proc. of a Conf. on IAU Symposium No.303: The GC: Feeding and Feedback in a Normal Galactic Nucleus 2013 September 30 - October 4, Santa Fe New Mexico (USA)

We present the various science cases for building Band 1 receivers as part of ALMA's ongoing Development Program. We describe the new frequency range for Band 1 of 35-52 GHz, a range chosen to maximize the receiver suite's scientific impact. We first describe two key science drivers: 1) the evolution of grains in protoplanetary disks and debris disks, and 2) molecular gas in galaxies during the era of re-ionization. Studies of these topics with Band 1 receivers will significantly expand ALMA's Level 1 Science Goals. In addition, we describe a host of other exciting continuum and line science cases that require ALMA's high sensitivity and angular resolution. For example, ALMA Band 1 continuum data will probe the Sunyaev-Zel'dovich Effect in galaxy clusters, Very Small Grains and spinning dust, ionized jets from young stars, spatial and flaring studies of Sgr A*, the acceleration sites of solar flares, pulsar wind nebulae, radio supernovae, and X-ray binaries. Furthermore, ALMA Band 1 line data will probe chemical differentiation in cloud cores, complex carbon chain molecules, extragalactic radio recombination lines, masers, magnetic fields through Zeeman effect measurements, molecular outflows from young stars, the co-evolution of star formation and active galactic nuclei, and the molecular content of galaxies at z ~ 3. ALMA provides similar to better sensitivities than the JVLA over 35-50 GHz, with differences increasing with frequency. ALMA's smaller antennas and shorter baselines, greater number of baselines, and single-dish capabilities, however, give it a significant edge for observing extended emission, making wide-field maps (mosaics), or attaining high image fidelity, as required by the described science cases., Comment: 74 pages; this document is a major revision of one posted previously as arXiv:0910.1609

The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope, MALT90 has obtained 3' x 3' maps toward ~2000 dense molecular clumps identified in the ATLASGAL 870 um Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to HII regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38") and spectral (0.11 km/s) resolution, the data reveal a wealth of information about the clump's morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high resolution studies with ALMA., Comment: Accepted to PASA, 13 pages

We present a complete sample of molecular clumps containing compact and ultra-compact (UC) HII regions between \ell=10\degr and 60\degr\ and $|b|<1\degr, identified by combining the the ATLASGAL submm and CORNISH radio continuum surveys with visual examination of archival infrared data. Our sample is complete to optically thin, compact and UCHII regions driven by a zero age main sequence star of spectral type B0 or earlier embedded within a 1,000 Msun clump. In total we identify 213 compact and UCHII regions, associated with 170 clumps. Unambiguous kinematic distances are derived for these clumps and used to estimate their masses and physical sizes, as well as the Lyman continuum fluxes and sizes of their embedded HII regions. We find a clear lower envelope for the surface density of molecular clumps hosting massive star formation of 0.05 g cm^{-2}, which is consistent with a similar sample of clumps associated with 6.7 GHz masers. The mass of the most massive embedded stars is closely correlated with the mass of their natal clump. Young B stars appear to be significantly more luminous in the ultraviolet than predicted by current stellar atmosphere models. The properties of clumps associated with compact and UCHII regions are very similar to those associated with 6.7 GHz methanol masers and we speculate that there is little evolution in the structure of the molecular clumps between these two phases. Finally, we identify a significant peak in the surface density of compact and UCHII regions associated with the W49A star-forming complex, noting that this complex is truly one of the most massive and intense regions of star formation in the Galaxy., Comment: Accepted for publication in MNRAS. Paper consists of 29 pages, 26 figures and 4 tables. The resolution of Figures 21 and 25 has been reduced to comply with file size restrictions. Full versions of Figures 11 and 12 and Tables 3 and 4 will only be available in the electronic version of the journal and through CDS

The formation of high-mass stars is tightly linked to that of their parental clouds. We here focus on the high-density parts of W43, a molecular cloud undergoing an efficient event of formation. The cloud structure is studied with a column density image derived from Herschel continuum maps obtained at 70, 160, 250, 350, and 500 micron. We identify two high-column density filamentary clouds, quoted as the W43-MM1 and W43-MM2 ridges, which both account for 1.5x10^4 Msun gas mass above 10^23 cm-2 and within areas of 5 and 14pc^2, respectively. We used the N_2H^+ 1--0 line to confirm that the W43-MM1 and W43-MM2 ridges are structures coherent in velocity and gravitationally bound, despite their large velocity dispersion and ~5 kms line widths. The most intriguing result of the W43 large program is the bright wide-spread SiO 2--1 emission: 1--11 K kms$ stretching an area of ~28 pc^2. Concentrated toward the W43-MM1 and W43-MM2 ridges and their immediate surroundings, it leads to a total luminosity of L_SiO 2-1 ~4 10^4 K kms kpc^2pc^2. We measured a steep relation between the luminosity and velocity extent of the SiO~2--1 lines and propose to use it to distinguish the low-velocity shocks observed here from the more classical high-velocity ones associated with outflows of high-mass young stellar objects. We used state-of-the-art shock models to demonstrate that low-velocity (<10 kms^-1) shocks with a small amount (10%) of Si atoms initially in gas phase or in grain mantles can explain the observed SiO column density in W43. The spatial and velocity overlaps between the ridges high-density gas (n_H2>10^4-10^5 cm^-3) and the shocked SiO gas suggests that ridges could be forming via colliding flows driven by gravity and accompanied by low-velocity shocks. This mechanism may be the initial conditions for the formation of young massive clusters in these ridges., Comment: accepted for publication to ApJ in July 2013

Despite increasing research in massive star formation, little is known about its earliest stages. Infrared Dark Clouds (IRDCs) are cold, dense and massive enough to harbour the sites of future high-mass star formation. But up to now, mainly small samples have been observed and analysed. To understand the physical conditions during the early stages of high-mass star formation, it is necessary to learn more about the physical conditions and stability in relatively unevolved IRDCs. Thus, for characterising IRDCs studies of large samples are needed. We investigate a complete sample of 218 northern hemisphere high-contrast IRDCs using the ammonia (1,1)- and (2,2)-inversion transitions. We detected ammonia (1,1)-inversion transition lines in 109 of our IRDC candidates. Using the data we were able to study the physical conditions within the star-forming regions statistically. We compared them with the conditions in more evolved regions which have been observed in the same fashion as our sample sources. Our results show that IRDCs have, on average, rotation temperatures of 15 K, are turbulent (with line width FWHMs around 2 km s$^{-1}$), have ammonia column densities on the order of $10^{14}$ cm$^{-2}$ and molecular hydrogen column densities on the order of $10^{22}$ cm$^{-2}$. Their virial masses are between 100 and a few 1000 M$_\odot$. The comparison of bulk kinetic and potential energies indicate that the sources are close to virial equilibrium. IRDCs are on average cooler and less turbulent than a comparison sample of high-mass protostellar objects, and have lower ammonia column densities. Virial parameters indicate that the majority of IRDCs are currently stable, but are expected to collapse in the future., Comment: 21 pages, 11 figures, 7 tables. Paper accepted for publication in Astronomy & Astrophysics

Using the 870-$\mu$m APEX Telescope Large Area Survey of the Galaxy (ATLASGAL), we have identified 577 submillimetre continuum sources with masers from the methanol multibeam (MMB) survey in the region $280\degr < \ell < 20\degr$; $|\,b\,| < 1.5\degr$. 94\,per\,cent of methanol masers in the region are associated with sub-millimetre dust emission. We estimate masses for ~450 maser-associated sources and find that methanol masers are preferentially associated with massive clumps. These clumps are centrally condensed, with envelope structures that appear to be scale-free, the mean maser position being offset from the peak column density by 0.0 \pm 4". Assuming a Kroupa initial mass function and a star-formation efficiency of ~30\,per\,cent, we find that over two thirds of the clumps are likely to form clusters with masses >20\,\msun. Furthermore, almost all clumps satisfy the empirical mass-size criterion for massive star formation. Bolometric luminosities taken from the literature for ~100 clumps range between ~100 and 10$^6$\,\lsun. This confirms the link between methanol masers and massive young stars for 90\,per\,cent of our sample. The Galactic distribution of sources suggests that the star-formation efficiency is significantly reduced in the Galactic-centre region, compared to the rest of the survey area, where it is broadly constant, and shows a significant drop in the massive star-formation rate density in the outer Galaxy. We find no enhancement in source counts towards the southern Scutum-Centaurus arm tangent at $\ell ~ 315\degr$, which suggests that this arm is not actively forming stars., Comment: 25 pages, 23 figures, 4 tables. The resolution of Figs. 1, 18 and 23 have been reduced to comply with file size restrictions, but high resolution version of the paper is available on request. Paper accepted for publication in MNRAS

We analyze the carbon monoxide emission around the star WR 16 aiming to chieve a better understanding of the interaction between massive stars with their surroundings. We study the molecular gas in a region of 86.'4 x 86.'4 in size using CO (J=1-0) and 13CO (J=1-0) line data obtained with the 4-m NANTEN telescope. Radio continuum archival data at 4.85 GHz, obtained from the Parkes-MIT-NRAO Southern Radio Survey, are also analyzed to account for the ionized gas. Available IRAS (HIRES) 60 and 100 microns images are used to study the characteristics of the dust around the star. Our new CO and 13CO data allow the low/intermediate density molecular gas surrounding the WR nebula to be completely mapped. We report two molecular features at -5 km/s and -8.5 km/s (component 1 and component 2, respectively) having a good morphological resemblance with the Halpha emission of the ring nebula. Component 2 seems to be associated with the external ring, whilst component 1 is placed at the interface between component 2 and the Halpha emission. We also report a third molecular feature 10' in size (component 3) at a velocity of -9.5 km/s having a good morphological correspondence with the inner optical and IR emission, although high resolution observations are recommended to confirm its existence. The stratified morphology and kinematics of the molecular gas could be associated to shock fronts and high mass-loss events related to different evolutive phases of the WR star, which have acted upon the surrounding circumstellar molecular gas. An analysis of the mass of component 1 suggests that this feature is composed by swept-up interstellar gas and is probably enriched by molecular ejecta. The direction of the proper motion of WR 16 suggests that the morphology of the inner ring nebula is induced by the stellar motion., Comment: 10 pages, 7 figures. Accepted for publication in A&A

Context. The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) is the first systematic survey of the inner Galactic plane in the sub-millimetre. The observations were carried out with the Large APEX Bolometer Camera (LABOCA), an array of 295 bolometers observing at 870 microns (345 GHz). Aims. Here we present a first version of the compact source catalogue extracted from this survey. This catalogue provides an unbiased database of dusty clumps in the inner Galaxy. Methods. The construction of this catalogue was made using the source extraction routine SExtractor. We have cross-associated the obtained sources with the IRAS and MSX catalogues, in order to constrain their nature. Results. We have detected 6639 compact sources in the range from 330 < l < 21 degrees and |b| < 1.5 degrees. The catalogue has a 99% completeness for sources with a peak flux above 6 sigma, which corresponds to a flux density of ~0.4 Jy/beam. The parameters extracted for sources with peak fluxes below the 6 sigma completeness threshold should be used with caution. Tests on simulated data find the uncertainty in the flux measurement to be ~12%, however, in more complex regions the flux values can be overestimated by a factor of 2 due to the additional background emission. Using a search radius of 30" we found that 40% of ATLASGAL compact sources are associated with an IRAS or MSX point source, but, ~50% are found to be associated with MSX 21 microns fluxes above the local background level, which is probably a lower limit to the actual number of sources associated with star formation. Conclusions. Although infrared emission is found towards the majority of the clumps detected, this catalogue is still likely to include a significant number of clumps that are devoid of star formation activity and therefore excellent candidates for objects in the coldest, earliest stages of (high-mass) star formation., Comment: The full catalogue and the calibrated emission maps are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or via http://cdsweb.u-strasbg.fr/cgibin/qcat?J/A+A/

Context: It is well known that the kinetic temperatures, Tkin, of the molecular clouds in the Galactic center region are higher than in typical disk clouds. However, the Tkin of the molecular complexes found at higher latitudes towards the giant molecular loops in the central region of the Galaxy is so far unknown. The gas of these high latitude molecular clouds (hereafter referred to as halo clouds) is located in a region where the gas in the disk may interact with the gas in the halo in the Galactic center region. Aims: To derive Tkin in the molecular clouds at high latitude and understand the physical process responsible for the heating of the molecular gas both in the Central Molecular Zone (the concentration of molecular gas in the inner 500 pc) and in the giant molecular loops. Methods: We measured the metastable inversion transitions of NH3 from (1,1) to (6,6) toward six positions selected throughout the Galactic central disk and halo. We used rotational diagrams and large velocity gradient modeling to estimate the kinetic temperatures toward all the sources. We also observed other molecules like SiO, HNCO, CS, C34S, C18O, and 13CO, to derive the densities and to trace different physical processes (shocks, photodissociation, dense gas) expected to dominate the heating of the molecular gas. Results: We derive for the first time Tkin of the high latitude clouds interacting with the disk in the Galactic center region. We find high rotational temperatures in all the observed positions. We derive two kinetic temperature components (150 K and 40 K) for the positions in the Central Molecular Zone, and only the warm kinetic temperature component for the clouds toward the giant molecular loops. The fractional abundances derived from the different molecules suggest that shocks provide the main heating mechanism throughout the Galactic center, also at high latitudes, Comment: accepted for publication in A&A 06/09/2012

The APEX Telescope Large Area Survey: The Galaxy (ATLASGAL) is an unbiased continuum survey of the inner Galactic disk at 870 \mu m. It covers +/- 60 deg in Galactic longitude and aims to find all massive clumps at various stages of high-mass star formation in the inner Galaxy, particularly the earliest evolutionary phases. We aim to determine properties such as the gas kinetic temperature and dynamics of new massive cold clumps found by ATLASGAL. Most importantly, we derived their kinematical distances from the measured line velocities. We observed the ammonia (J,K) = (1,1) to (3,3) inversion transitions toward 862 clumps of a flux-limited sample of submm clumps detected by ATLASGAL and extracted 13CO (1-0) spectra from the Galactic Ring Survey (GRS). We determined distances for a subsample located at the tangential points (71 sources) and for 277 clumps whose near/far distance ambiguity is resolved. Most ATLASGAL clumps are cold with rotational temperatures from 10-30 K. They have a wide range of NH3 linewidths, which by far exceeds the thermal linewidth, as well as a broad distribution of high column densities with an NH3 abundance in the range of 5 to 30 * 10^{-8}. We found an enhancement of clumps at Galactocentric radii of 4.5 and 6 kpc. The high detection rate (87%) confirms ammonia as an excellent probe of the molecular content of the massive, cold clumps revealed by ATLASGAL. A clear trend of increasing rotational temperatures and linewidths with evolutionary stage is seen for source samples ranging from 24 \mu m dark clumps to clumps with embedded HII regions. The survey provides the largest ammonia sample of high-mass star forming clumps and thus presents an important repository for the characterization of statistical properties of the clumps and the selection of subsamples for detailed, high-resolution follow-up studies.

The Q/U Imaging ExperimenT (QUIET) has observed the cosmic microwave background (CMB) at 43 and 95GHz. The 43-GHz results have been published in QUIET Collaboration et al. (2011), and here we report the measurement of CMB polarization power spectra using the 95-GHz data. This data set comprises 5337 hours of observations recorded by an array of 84 polarized coherent receivers with a total array sensitivity of 87 uK sqrt(s). Four low-foreground fields were observed, covering a total of ~1000 square degrees with an effective angular resolution of 12.8', allowing for constraints on primordial gravitational waves and high-signal-to-noise measurements of the E-modes across three acoustic peaks. The data reduction was performed using two independent analysis pipelines, one based on a pseudo-Cl (PCL) cross-correlation approach, and the other on a maximum-likelihood (ML) approach. All data selection criteria and filters were modified until a predefined set of null tests had been satisfied before inspecting any non-null power spectrum. The results derived by the two pipelines are in good agreement. We characterize the EE, EB and BB power spectra between l=25 and 975 and find that the EE spectrum is consistent with LCDM, while the BB power spectrum is consistent with zero. Based on these measurements, we constrain the tensor-to-scalar ratio to r=1.1+0.9-0.8 (r<2.8 at 95% C.L.) as derived by the ML pipeline, and r=1.2+0.9-0.8 (r<2.7 at 95% C.L.) as derived by the PCL pipeline. In one of the fields, we find a correlation with the dust component of the Planck Sky Model, though the corresponding excess power is small compared to statistical errors. Finally, we derive limits on all known systematic errors, and demonstrate that these correspond to a tensor-to-scalar ratio smaller than r=0.01, the lowest level yet reported in the literature., Comment: 10 pages, 6 figures, 3 tables, submitted to ApJ, This paper should be cited as "QUIET Collaboration (2012)." v2: updated to reflect published version

In this study, we present an unbiased sample of the earliest stages of massive star formation across 20 square-degree of the sky. Within the region 10deg < l < 20deg and |b| < 1deg, we search the ATLASGAL survey at 870 micron for dense gas condensations. These clumps are carefully examined for indications of ongoing star formation using YSOs from the GLIMPSE source catalog as well as sources in the 24 micron MIPSGAL images, to search for starless clumps. We calculate the column densities as well as the kinematic distances and masses for sources where the v_lsr is known from spectroscopic observations. Within the given region, we identify 210 starless clumps with peak column densities > 1 x 10e23 cm^(-2). In particular, we identify potential starless clumps on the other side of the Galaxy. The sizes of the clumps range between 0.1 pc and 3 pc with masses between a few tens of solar masses up to several ten thousands of solar masses. Most of them may form massive stars, but in the 20 square-degree we only find 14 regions massive enough to form stars more massive than 20 solar masses and 3 regions with the potential to form stars more massive than 40 40 solar masses. The slope of the high-mass tail of the clump mass function for clumps on the near side of the Galaxy is 2.2 and, therefore, Salpeter-like. We estimate the lifetime of the most massive starless clumps to be 60000 yr. The sample offers a uniform selection of starless clumps. In the large area surveyed, we only find a few potential precursors of stars in the excess of 40 solar masses. It appears that the lifetime of these clumps is somewhat shorter than their free-fall times, although both values agree within the errors. In addition, these are ideal objects for detailed studies and follow-up observations., Comment: 15 pages plus appendix, in total 44 pages, accepted for publication in Astronomy & Astrophysics, full tables will be added soon

The ATLASGAL 870mum continuum survey conducted with the APEX telescope is the first survey covering the whole inner Galactic plane (60deg>l>-60deg & b<1.5deg) in submm continuum emission tracing the cold dust of dense and young star-forming regions. Here, we present the overall distribution of sources within our Galactic disk. The submm continuum emission is confined to a narrow range around the galactic plane, but shifted on average by ~0.07deg below the plane. Source number counts show strong enhancements toward the Galactic center, the spiral arms and toward prominent star-forming regions. Comparing the distribution of ATLASGAL dust continuum emission to that of young intermediate- to high-mass young stellar objects (YSOs) derived from Spitzer data, we find similarities as well as differences. In particular, the distribution of submm dust continuum emission is significantly more confined to the plane than the YSO distribution (FWHM of 0.7 and 1.1deg, corresponding to mean physical scale heights of approximately 46 and 80pc, respectively). While this difference may partly be caused by the large extinction from the dense submm cores, gradual dispersal of stellar distributions after their birth could also contribute to this effect. Compared to other tracers of Galactic structure, the ATLASGAL data are strongly confined to a narrow latitude strip around the Galactic plane., Comment: 7 pages, 6 figures, accepted for the Astrophysical Journal, high-resolution version at http://www.mpia-hd.mpg.de/homes/beuther/papers.html

The ESO Public Survey VISTA Variables in the Via Lactea (VVV) started in 2010. VVV targets 562 sq. deg in the Galactic bulge and an adjacent plane region and is expected to run for ~5 years. In this paper we describe the progress of the survey observations in the first observing season, the observing strategy and quality of the data obtained. The observations are carried out on the 4-m VISTA telescope in the ZYJHKs filters. In addition to the multi-band imaging the variability monitoring campaign in the Ks filter has started. Data reduction is carried out using the pipeline at the Cambridge Astronomical Survey Unit. The photometric and astrometric calibration is performed via the numerous 2MASS sources observed in each pointing. The first data release contains the aperture photometry and astrometric catalogues for 348 individual pointings in the ZYJHKs filters taken in the 2010 observing season. The typical image quality is ~0.9-1.0". The stringent photometric and image quality requirements of the survey are satisfied in 100% of the JHKs images in the disk area and 90% of the JHKs images in the bulge area. The completeness in the Z and Y images is 84% in the disk, and 40% in the bulge. The first season catalogues contain 1.28x10^8 stellar sources in the bulge and 1.68x10^8 in the disk area detected in at least one of the photometric bands. The combined, multi-band catalogues contain more than 1.63x10^8 stellar sources. About 10% of these are double detections due to overlapping adjacent pointings. These overlapping multiple detections are used to characterise the quality of the data. The images in the JHKs bands extend typically ~4 mag deeper than 2MASS. The magnitude limit and photometric quality depend strongly on crowding in the inner Galactic regions. The astrometry for Ks=15-18 mag has rms ~35-175 mas., Comment: Accepted for publication in Astronomy and Astrophysics (Section 14: Catalogs and data)

We attempt to make a complete census of massive-star formation within all of GMC G345.5+1.0. This cloud is located one degree above the galactic plane and at 1.8 kpc from the Sun, thus there is little superposition of dust along the line-of-sight, minimizing confusion effects in identifying individual clumps. We observed the 1.2 mm continuum emission across the whole GMC using the Swedish-ESO Submillimetre Telescope Imaging Bolometer Array mounted on the SEST. Observations have a spatial resolution of 0.2 pc and cover 1.8 deg\times 2.2 deg in the sky with a noise of 20 mJy/beam. We identify 201 clumps with diameters between 0.2 and 0.6 pc, masses between 3.0 and 1.3\times10^3 Msun, and densities between 5\times10^3 and 4\times10^5 cm^-3. The total mass of the clumps is 1.2\times10^4 Msun, thus the efficiency in forming these clumps, estimated as the ratio of the total clump mass to the total GMC mass, is 0.02. The clump mass distribution for masses between 10 and 10^3 Msun is well-fitted by a power law dN/dM proportional to M^-alpha, with a spectral mass index alpha of 1.7+/-0.1. Given their mass distribution, clumps do not appear to be the direct progenitors of single stars. Comparing the 1.2 mm continuum emission with infrared images taken by the Midcourse Space Experiment (MSX) and by the SPITZER satellite, we find that at least 20% of the clumps are forming stars, and at most 80% are starless. Six massive-star forming regions embedded in clumps and associated with IRAS point sources have mean densities of ~10^5 cm^-3, luminosities >10^3 Lsun, and spectral energy distributions that can be modeled with two dust components at different mean temperatures of 28+/-5 and 200+/-10 K.

The diffuse cm-wave IR-correlated signal, the "anomalous" CMB foreground, is thought to arise in the dust in cirrus clouds. We present Cosmic Background Imager (CBI) cm-wave data of two translucent clouds, {\zeta} Oph and LDN 1780 with the aim of characterising the anomalous emission in the translucent cloud environment. In {\zeta} Oph, the measured brightness at 31 GHz is 2.4{\sigma} higher than an extrapolation from 5 GHz measurements assuming a free-free spectrum on 8 arcmin scales. The SED of this cloud on angular scales of 1{\odot} is dominated by free-free emission in the cm-range. In LDN 1780 we detected a 3 {\sigma} excess in the SED on angular scales of 1{\odot} that can be fitted using a spinning dust model. In this cloud, there is a spatial correlation between the CBI data and IR images, which trace dust. The correlation is better with near-IR templates (IRAS 12 and 25 {\mu}m) than with IRAS 100 {\mu}m, which suggests a very small grain origin for the emission at 31 GHz. We calculated the 31 GHz emissivities in both clouds. They are similar and have intermediate values between that of cirrus clouds and dark clouds. Nevertheless, we found an indication of an inverse relationship between emissivity and column density, which further supports the VSGs origin for the cm-emission since the proportion of big relative to small grains is smaller in diffuse clouds., Comment: 13 pages, 14 figures, 7 tables. Accepted for publication in MNRAS

We used a large database extracted from Galaxy-wide surveys of H {\scriptsize I}, $^{13}$CO 1-0, $8 \micron$ and $870 \micron$ continuum to trace diffuse atomic gas, low- to medium-density molecular gas, high-density molecular gas, and star formation activity which we complemented by dedicated $^{12}$CO 2--1, 3--2 observations of the W43 region. From the detailed 3D (space-space-velocity) analysis of the molecular and atomic cloud tracers through the region and despite its wide velocity range (\emph{FWHM}$\sim22.3 \kms$ around $\vlsr\sim 95.9 \kms$), we identified W43 as a large (equivalent diameter $\sim 140$ pc) and coherent complex of molecular clouds which is surrounded by an atomic gas envelope (equivalent diameter $\sim 290$ pc). We measured the total mass of this newly-identified molecular complex ($M_{{\tiny total}}\sim 7.1 \times 10^6 \msun$), the mass contained in dense $870 \micron$ clumps ($<5$ pc dense cloud structures, $M_{{\tiny clumps}}\sim 8.4 \times 10^5 \msun$) and conclude that W43 is particularly massive and concentrated. The distance we assume for the W43 complex is 6 kpc from the Sun, which may place it at the meeting point of the Scutum-Centaurus (or Scutum-Crux) Galactic arm and the Bar, a dynamically complex region where high-velocity streams could easily collide. The star formation rate of W43 is suggested not to be steady but it is increasing from $\, \sim 0.01 \msun\, {yr}^{-1}$ (measured from its $8\,\mu$m luminosity) to $\sim 0.1 \msun\, {yr}^{-1}$ (measured from its molecular content). From the global properties of W43, we claim it is an extreme molecular complex in the Milky Way and it could even be forming starburst clusters in the near future., Comment: 16 pages, accepted for A&A (14 Feb 2011)

The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43GHz and 95GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the CMB. QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, >10,000hours of data were collected, first with the 19-element 43GHz array (3458hours) and then with the 90-element 95GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ~1000deg^2. This paper reports initial results from the 43GHz receiver which has an array sensitivity to CMB fluctuations of 69uK sqrt(s). The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB and EB power spectra in the multipole range ell=25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3sigma significance, the E-mode spectrum is consistent with the LCDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r=0.35+1.06-0.87. The combination of a new time-stream double-demodulation technique, Mizuguchi-Dragone optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r=0.1, Comment: 19 pages, 14 figures, higher quality figures are available at http://quiet.uchicago.edu/results/index.html; Fixed a typo and corrected statistical error values used as a reference in Figure 14, showing our systematic uncertainties (unchanged) vs. multipole; Revision to ApJ accepted version, this paper should be cited as "QUIET Collaboration et al. (2011)"

Aims: We aim at deriving the excitation conditions of the interstellar gas as well as the local FUV intensities in the molecular cloud surrounding NGC 3603 to get a coherent picture of how the gas is energized by the central stars. Methods: The NANTEN2-4m submillimeter antenna is used to map the [CI] 1-0, 2-1 and CO 4-3, 7-6 lines in a 2' x 2' region around the young OB cluster NGC 3603 YC. These data are combined with C18O 2-1 data, HIRES-processed IRAS 60 and 100 micron maps of the FIR continuum, and Spitzer/IRAC maps. Results: The NANTEN2 observations show the presence of two molecular clumps located south-east and south-west of the cluster and confirm the overall structure already found by previous CS and C18O observations. We find a slight position offset of the peak intensity of CO and [CI], and the atomic carbon appears to be further extended compared to the molecular material. We used the HIRES far-infrared dust data to derive a map of the FUV field heating the dust. We constrain the FUV field to values of \chi = 3 - 6 \times 10^3 in units of the Draine field across the clouds. Approximately 0.2 to 0.3 % of the total FUV energy is re-emitted in the [CII] 158 {\mu}m cooling line observed by ISO. Applying LTE and escape probability calculations, we derive temperatures (TMM1 = 43 K, TMM2 = 47 K), column densities (N(MM1) = 0.9 \times 10^22 cm^-2, N(MM2) = 2.5 \times 10^22 cm^-2) and densities (n(MM1) = 3 \times 10^3 cm^-3, n(MM2) = 10^3 -10^4 cm^-3) for the two observed molecular clumps MM1 and MM2. Conclusions: The cluster is strongly interacting with the ambient molecular cloud, governing its structure and physical conditions. A stability analysis shows the existence of gravitationally collapsing gas clumps which should lead to star formation. Embedded IR sources have already been observed in the outskirts of the molecular cloud and seem to support our conclusions., Comment: 13 pages, 10 figures, accepted for publication by A&A

Some theoretical models propose that O-B stars form via accretion, in a similar fashion to low-mass stars. Jet-driven molecular outflows play an important role in this scenario, and their study can help to understand the process of high-mass star formation and the different evolutionary phases involved. Observations towards low-mass protostars so far favour an evolutionary picture in which jets are always associated with Class 0 objects while more evolved Class I/II objects show less evidence of powerful jets. The present study aims at checking whether an analogous picture can be found in the high-mass case. The IRAM 30-m telescope (Spain) has been used to perform single-pointing SiO(2-1) and (3-2) observations towards a sample of 57 high-mass molecular clumps in different evolutionary stages. Continuum data at different wavelengths, from mid-IR to 1.2 mm, have been gathered to build the spectral energy distributions of all the clumps and estimate their bolometric luminosities. SiO emission at high velocities, characteristic of molecular jets, is detected in 88% of our sources, a very high detection rate indicating that there is ongoing star formation activity in most of the sources of our sample. The SiO(2-1) luminosity drops with L/M, which suggests that jet activity declines as time evolves. This represents the first clear evidence of a decrease of SiO outflow luminosity with time in a homogeneous sample of high-mass molecular clumps in different evolutionary stages. The SiO(3-2) to SiO(2-1) integrated intensity ratio shows only minor changes with evolutionary state., Comment: 12 pages, 10 figures

Ams: We study the 12C/13C isotopic ratio in the disk of the central molecular zone and in the halo to trace gas accretion toward the Galactic center region in the Milky Way. Methods: Using the IRAM 30m telescope, we observe the J=1-0 rotational transition of HCO+, HCN, HNC and their 13C isotopic substitutions in order to measure the 12C/13C isotopic ratio. We observe 9 positions selected throughout the Galactic center region, including clouds at high latitude; locations where the X1 and X2 orbits associated with the barred potential are expected to intersect; and typical Galactic center molecular clouds. Results: We find a systematically higher 12C/13C isotopic ratio (>40) toward the halo and the X1 orbits than for the Galactic center molecular clouds (20-25). Our results point out to molecular gas which has undergone a different degree of nuclear processing than that observed in the gas towards the inner Galactic center region. Conclusions: The high isotopic ratios are consistent with the accretion of the gas from the halo and from the outskirts of the Galactic disk., Comment: 8 pages, 2 figures, accepted for publication in A&A

We attempt to determine the nature of the bubbles observed by Spitzer in the Galactic plane, mainly to establish if possible their association with massive stars. We take advantage of the very simple morphology of these objects to search for star formation triggered by HII regions, and to estimate the importance of this mode of star formation. We consider a sample of 102 bubbles detected by Spitzer-GLIMPSE, and catalogued by Churchwell et al.(2006). We use mid-infrared and radio-continuum public data to discuss their nature. We use the ATLASGAL survey at 870 micron to search for dense neutral material collected on their borders. Results: We find that 86% of the bubbles contain ionized gas detected by means of its radio-continuum emission at 20-cm. Thus, most of the bubbles observed at 8.0 micron enclose HII regions ionized by O-B2 stars. Ninety-eight percent of the bubbles exhibit 24 micron emission in their central regions. The ionized regions at the center of the 8.0 micron bubbles seem to be devoid of PAHs but contain hot dust. Among the 65 regions for which the angular resolution of the observations is high enough to resolve the spatial distribution of cold dust at 870 micron, we find that 40% are surrounded by cold dust, and that another 28% contain interacting condensations. The former are good candidates for the collect and collapse process, as they display an accumulation of dense material at their borders. The latter are good candidates for the compression of pre-existing condensations by the ionized gas. Eighteen bubbles exhibit associated ultracompact HII regions and/or methanol masers in the direction of dust condensations adjacent to their ionization fronts. Our results suggest that more than a quarter of the bubbles may have triggered the formation of massive objects., Comment: 36 pages, 27 figures, 500 figures online at http://lamwws.oamp.fr/bubbles. Paper accepted by A&A

We present single-dish (sub)millimeter observations of gas and dust in the Galactic high-mass star-forming region G19.61-0.23, with the aim of studying the large-scale properties and physical conditions of the molecular gas across the region. The final aim is to compare the large-scale (about 100 pc) properties with the small-scale (about 3 pc) properties and to consider possible implications for extragalactic studies. We have mapped CO isotopologues in the J=1-0 transition using the FCRAO-14m telescope and the J=2-1 transition using the IRAM-30m telescope. We have also used data from the ATLASGAL survey and from the BU-FCRAO Galactic Ring Survey, as well as the Spitzer infrared Galactic plane surveys GLIMPSE and MIPSGAL to characterize the star-formation activity within the molecular clouds. We reveal a population of molecular clumps in the 13CO(1-0) emission. Our analysis of the 13CO suggests that the virial parameter (ratio of kinetic to gravitational energy) varies over an order of magnitude between clumps that are unbound and some that are apparently "unstable". This conclusion is independent of whether they show evidence of ongoing star formation. We find that the majority of ATLASGAL sources have MIPSGAL counterparts with luminosities in the range 10^4 - 5 10^4 Lsun and are presumably forming relatively massive stars. We compare our results with previous extragalactic studies of the nearby spiral galaxies M31 and M33; and the blue compact dwarf galaxy Henize2-10. We find that the main giant molecular cloud surrounding G19.61-0.23 has physical properties typical for Galactic GMCs and which are comparable to the GMCs in M31 and M33. However, the GMC studied here shows smaller surface densities and masses than the clouds identified in Henize2-10 and associated with super star cluster formation., Comment: Accepted for publication in Astronomy & Astrophysics

Aims: A large scale survey of the Galactic center region in he 3 mm rotational transitions of SiO, HCO+ and H13CO+ (beamsize ~ 3. 6 arcmin) was conducted to provide an estimate of cloud conditions, heating mechanisms, chemistry and other properties. Methods: Using the NANTEN 4m telescope from Nagoya University, a region between -5.75

RX J1713.7-3946 is one of the TeV {\gamma}-ray supernova remnants (SNRs) emitting synchrotron X rays. The SNR is associated with molecular gas located at ~1 kpc. We made new molecular observations toward the dense cloud cores, peaks A, C and D, in the SNR in the 12CO(J=2-1) and 13CO(J=2-1) transitions at angular resolution of 90". The most intense core in 13CO, peak C, was also mapped in the 12CO(J=4-3) transition at angular resolution of 38". Peak C shows strong signs of active star formation including bipolar outflow and a far-infrared protostellar source and has a steep gradient with a r^{-2.2$\pm$0.4} variation in the average density within radius r. Peak C and the other dense cloud cores are rim-brightened in synchrotron X rays, suggesting that the dense cloud cores are embedded within or on the outer boundary of the SNR shell. This confirms the earlier suggestion that the X rays are physically associated with the molecular gas (Fukui et al. 2003). We present a scenario where the densest molecular core, peak C, survived against the blast wave and is now embedded within the SNR. Numerical simulations of the shock-cloud interaction indicate that a dense clump can indeed survive shock erosion, since shock propagation speed is stalled in the dense clump. Additionally, the shock-cloud interaction induces turbulence and magnetic field amplification around the dense clump that may facilitate particle acceleration in the lower-density inter-clump space leading to the enhanced synchrotron X rays around dense cores., Comment: 22 pages, 7 figures, to accepted in The Astrophysical Journal. A full color version with higher resolution figures is available at http://www.a.phys.nagoya-u.ac.jp/~sano/ApJ10/ms_sano.pdf

We report on the discovery of a molecular cavity in the Norma near arm in the general direction of Westerlund 1 (Wd1), but not associated with it. The cavity has a mean radial velocity of -91.5 kms^{-1}, which differs by as much as ~40 kms^{-1} from the mean radial velocity of the Wd1 stars. The cavity is surrounded by a fragmented molecular shell of an outer diameter of about 100 pc and 10^{6} M_odot, which is expanding at velocities of 6 to 8 kms^{-1}. The amount of kinetic energy involved in the expanding shell is ~10^{51} erg. Inside this cavity the atomic HI gas surface density is also the lowest. Structure of the extended Very High Energetic (VHE) gamma-ray emission, recently reported by the H.E.S.S. collaboration Ohm et al. 2009, coincides with the cavity. The observed morphology suggests that the inner wall of the molecular shell is the zone of the gamma-ray emission, and not the dense gas surrounding massive stars of Wd1 as had been speculated by the H.E.S.S. collaboration. A likely candidate responsible for creating the observed cavity and the gamma-ray emission is the pulsar PSR J1648-4611., Comment: Accepted for publication in The Astrophysical Journal Letters

We study the disk-halo interaction, in the context of orbits and Giant Molecular loops (GMLs) in the Galactic center (GC) region. We present a large scale survey in the central kpc in SiO(J=2-1), HCO$^+$(J=1-0) and H$^{13}$CO$^+$ (J=1-0), observations in 3mm lines toward a region in two clumps M+5.3-0.3 and M-3.8+0.9 placed in the foot point of two molecular loops, and observations toward selected positions, to trace accretion of the gas from the halo, Comment: Proceedings of the Galactic Center Workshop 2009, Shanghai. To be published in the Astronomical Society of the Pacific Conference Series

We describe the public ESO near-IR variability survey (VVV) scanning the Milky Way bulge and an adjacent section of the mid-plane where star formation activity is high. The survey will take 1929 hours of observations with the 4-metre VISTA telescope during five years (2010-2014), covering ~10^9 point sources across an area of 520 deg^2, including 33 known globular clusters and ~350 open clusters. The final product will be a deep near-IR atlas in five passbands (0.9-2.5 microns) and a catalogue of more than 10^6 variable point sources. Unlike single-epoch surveys that, in most cases, only produce 2-D maps, the VVV variable star survey will enable the construction of a 3-D map of the surveyed region using well-understood distance indicators such as RR Lyrae stars, and Cepheids. It will yield important information on the ages of the populations. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, INTEGRAL, WISE, Fermi LAT, XMM-Newton, GAIA and ALMA for a complete understanding of the variable sources in the inner Milky Way. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its globular cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star forming regions in the disk. The combined variable star catalogues will have important implications for theoretical investigations of pulsation properties of stars., Comment: accepted for publication in New Astronomy

We present sensitive NIR (J, H and K) imaging observations toward four luminous massive star forming regions in the Norma Spiral Arm: G324.201+0.119, G328.307+0.432, G329.337+0.147 and G330.949-0.174. We identify three clusters of young stellar objects (YSO) based on surface density diagnostics. We also find that sources detected only in the H and K-bands and with colors corresponding to spectral types earlier than B2, are likely YSOs. We analyze the spatial distribution of stars of different masses and find signatures in two clusters of primordial mass segregation which can't be explained as due to incompleteness effects. We show that dynamic interactions of cluster members with the dense gas from the parent core can explain the observed mass segregation, indicating that the gas plays an important role in the dynamics of young clusters., Comment: Submitted to ApJ in September 2009

We present a set of compelling science cases for the ALMA Band 1 receiver suite. For these cases, we assume in tandem the updated nominal Band 1 frequency range of 35-50 GHz with a likely extension up to 52 GHz; together these frequencies optimize the Band 1 science return. The scope of the science cases ranges from nearby stars to the re-ionization edge of the Universe. Two cases provide additional leverage on the present ALMA Level One Science Goals and are seen as particularly powerful motivations for building the Band 1 Receiver suite: (1) detailing the evolution of grains in protoplanetary disks, as a complement to the gas kinematics, requires continuum observations out to ~35 GHz (~9mm); and (2) detecting CO 3-2 line emission from galaxies like the Milky Way during the epoch of re-ionization, i.e., 6 < z < 10, also requires Band 1 receiver coverage. The range of Band 1 science is wide, however, and includes studies of very small dust grains in the ISM, pulsar wind nebulae, radio supernovae, X-ray binaries, the Galactic Center (i.e., Sgr A*), dense cloud cores, complex carbon-chain molecules, masers, magnetic fields in the dense ISM, jets and outflows from young stars, distant galaxies, and galaxy clusters (i.e., the Sunyaev-Zel'dovich Effect). A comparison of ALMA and the Jansky VLA (JVLA) at the same frequencies of Band 1 finds similar sensitivity performance at 40-50 GHz, with a slight edge for ALMA at higher frequencies (e.g., within a factor of 2 for continuum observations). With its larger number of instantaneous baselines, however, ALMA Band 1data will have greater fidelity than those from the JVLA at similar frequencies., Comment: 62 pages, 16 figures

(Abridged) Studying continuum emission from interstellar dust is essential to locating and characterizing the highest density regions in the interstellar medium. In particular, the early stages of massive star formation remain poorly understood. Our goal is to produce a large-scale, systematic database of massive pre- and proto-stellar clumps in the Galaxy, to understand how and under what conditions star formation takes place. A well characterized sample of star-forming sites will deliver an evolutionary sequence and a mass function of high-mass, star-forming clumps. This systematic survey at submm wavelengths also represents a preparatory work for Herschel and ALMA. The APEX telescope is ideally located to observe the inner Milky Way. The Large APEX Bolometer Camera (LABOCA) is a 295-element bolometer array observing at 870 microns, with a beam size of 19". Taking advantage of its large field of view (11.4') and excellent sensitivity, we started an unbiased survey of the Galactic Plane, with a noise level of 50-70 mJy/beam: the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). As a first step, we covered 95 sq. deg. These data reveal 6000 compact sources brighter than 0.25 Jy, as well as extended structures, many of them filamentary. About two thirds of the compact sources have no bright infrared counterpart, and some of them are likely to correspond to the precursors of (high-mass) proto-stars or proto-clusters. Other compact sources harbor hot cores, compact HII regions or young embedded clusters. Assuming a typical distance of 5 kpc, most sources are clumps smaller than 1 pc with masses from a few 10 to a few 100 M_sun. In this introductory paper, we show preliminary results from these ongoing observations, and discuss the perspectives of the survey., Comment: Accepted for publication in A&A, 13 pages, 14 figures. Final version after language editing

We present final results on the angular power spectrum of total intensity anisotropies in the CMB from the CBI. Our analysis includes all primordial anisotropy data collected between January 2000 and April 2005, and benefits significantly from an improved maximum likelihood analysis pipeline. It also includes results from a 30 GHz foreground survey conducted with the Green Bank Telescope (GBT) which places significant constraints on the possible contamination due to foreground point sources. We improve on previous CBI results by about a factor of two in the damping tail. These data confirm, at ~3-sigma, the existence of an excess of power over intrinsic CMB anisotropy on small angular scales (l > 1800). Using the GBT survey, we find currently known radio source populations are not capable of generating the power; a new population of faint sources with steeply rising spectral indices would be required to explain the excess with sources... We also present a full cosmological parameter analysis of the new CBI power spectrum... With CBI alone, the full parameter analysis finds the excess is 1.6-sigma above the level expected for a sigma_8=0.8 universe. We find the addition of high-l CMB data substantially improves constraints on cosmic string contributions to the TT power spectrum as well as the running of the scalar spectral index... We also present forecasts for what other experiments should see at different frequencies and angular resolutions given the excess power observed by CBI. We find that the reported high-l bandpowers from current high resolution CMB bolometer experiments are consistent with each other and CBI if the excess power is due to the SZE at the CBI-level of 2.5 +/- 1 times the sigma_8=0.8 standard SZ template. , Comment: 38 Pages, 9 Figures, 5 Tables v2 - fixed typos

IRAS19410+2336 is a young massive star forming region with an intense outflow activity. We present here spatially resolved NIR spectroscopy which allows us to verify whether the H2 emission detected in this object originates from thermal emission in shock fronts or from fluorescence excitation by non-ionizing UV photons. Moreover, NIR spectroscopy also offers the possibility of studying the characteristics of the putative driving source(s) of the H2 emission by the detection of photospheric and circumstellar spectral features, and of the environmental conditions (e.g. extinction). We obtained long-slit, intermediate-resolution, NIR spectra of IRAS19410+2336 using LIRIS. As a complement, we also obtained J, H and K_s images with the Las Campanas 2.5m Du Pont Telescope, and archival mid-infrared (MIR) Spitzer images at 3.6, 4.5, 5.8 and 8.0 um. We confirm the shocked nature of the H2 emission, with an excitation temperature of about 2000 K. We have also identified objects with very different properties and evolutionary stages in IRAS19410+2336. The most massive source at millimeter wavelengths, mm1, with a mass of a few tens of solar masses, has a bright NIR (and MIR) counterpart. This suggests that emission is leaking at these wavelengths. The second most massive millimeter source, mm2, is only detected at lambda > 6 um, suggesting that it could be a high-mass protostar still in its main accretion phase. The NIR spectra of some neighboring sources show CO first-overtone bandhead emission which is associated with neutral material located in the inner regions of the circumstellar environment of YSOs., Comment: 12 pages, 9 figures, online material, accepted for publication in A&A

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

We report millimeter interferometric observations of polarized continuum and line emission from the massive star forming region G34.4. Polarized thermal dust emission at 3 mm wavelength and CO $J=1 \to 0$ line emission were observed using the Berkeley-Illinois-Maryland Association (BIMA) array. Our results show a remarkably uniform polarization pattern in both dust and in CO J=$1 \to 0$ emission. In addition, the line emission presents a consistent uniform polarization pattern over most of the velocity channel maps. These uniform polarization patterns are aligned with the north-south main axis of the filament between the main millimeter source (MM) and the ultra-compact H {\scriptsize II} region, which are the central sources in G34.4, suggesting a magnetic field orthogonal to this axis. This morphology is consistent with a magnetically supported disk seen roughly edge-on., Comment: Accepted to be published at ApJ

Studying molecular gas in the central regions of the star burst galaxies NGC4945 and Circinus enables us to characterize the physical conditions and compare them to previous local and high-z studies. We estimate temperature, molecular density and column densities of CO and atomic carbon. Using model predictions we give a range of estimated CO/C abundance ratios. Using the new NANTEN2 4m sub-millimeter telescope in Pampa La Bola, Chile, we observed for the first time CO 4-3 and [CI] 3P1-3 P0 at the centers of both galaxies at linear scale of 682 pc and 732 pc respectively. We compute the cooling curves of 12CO and 13CO using radiative transfer models and estimate the physical conditions of CO and [CI]. The centers of NGC4945 and Circinus are very [CI] bright objects, exhibiting [CI] 3P1 - 3 P0 luminosities of 91 and 67Kkms-1kpc2, respectively. The [CI] 3P1-3 P0/CO 4-3 ratio of integrated intensities are large at 1.2 in NGC4945 and 2.8 in Circinus. Combining previous CO J= 1-0, 2-1 and 3-2 and 13CO J= 1-0, 2-1 studies with our new observations, the radiative transfer calculations give a range of densities, n(H2) = 10^3-3*104^cm-3, and a wide range of kinetic temperatures, Tkin = 20 - 100K, depending on the density. Future CO J= 7-6 and [CI] 2-1 observations will be important to resolve the ambiguity in the physical conditions and confirm the model predictions., Comment: 8 pages, 4 figures, accepted for publication in A&A

The Carina region is an excellent astrophysical laboratory for studying the feedback mechanisms of newly born, very massive stars within their natal giant molecular clouds (GMCs) at only 2.35 kpc distance. We use a clumpy PDR model to analyse the observed intensities of atomic carbon and CO and to derive the excitation conditions of the gas. The NANTEN2-4m submillimeter telescope was used to map the [CI] 3P1-3P0, 3P2-3P1 and CO 4-3, 7-6 lines in two 4'x4' regions of Carina where molecular material interfaces with radiation from the massive star clusters. One region is the northern molecular cloud near the compact OB cluster Tr14, and the second region is in the molecular cloud south of etaCar and Tr16. These data were combined with 13CO SEST spectra, HIRES/IRAS 60um and 100um maps of the FIR continuum, and maps of 8um IRAC/Spitzer and MSX emission. We used the HIRES far-infrared dust data to create a map of the FUV field heating the gas. The northern region shows an FUV field of a few 1000 in Draine units while the field of the southern region is about a factor 10 weaker. We constructed models consisting of an ensemble of small spherically symmetric PDR clumps within the 38" beam (0.43pc), which follow canonical power-law mass and mass-size distributions. We find that an average local clump density of 2x10**5 cm-3 is needed to reproduce the observed line emission at two selected interface positions. Stationary, clumpy PDR models reproduce the observed cooling lines of atomic carbon and CO at two positions in the Carina Nebula., Comment: accepted by A&A

We have observed the central region of the IR-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(1-0), 13CO(1-0), and C18O(1-0) line emission and with the Spitzer Space Telescope at mid-IR wavelengths. Five massive outflows from two cloud cores were discovered. Three outflows are centered on or near an Ultracompact HII region (G34.4+0.23) while the remaining two outflows originate from the millimeter core G34.4+0.23 MM. Modeling of the SEDs of the mid-IR sources identified 31 young stellar objects in the filament with a combined stellar mass of ~127 +/- 27 Msun. An additional 22 sources were identified as probable cluster members based on the presence of strong 24 micron emission. The total star formation efficiency in the G34.4 cloud filament is estimated to be ~7% while the massive and intermediate mass star formation efficiency in the entire cloud filament is estimated to be roughly 2%. A comparison of the gravitational binding energy with the outflow kinetic energy suggests that the compact core containing G34.4+0.23 MM is being destroyed by its molecular outflows whereas the outflows associated with more massive core surrounding the G34.4 UC HII region are not likely to totally disrupt the cloud. Additionally, a qualitative evaluation of the region appears to suggest that stars in this region may have formed in two stages: first lower mass stars formed and then, a few Myrs later, the more massive stars began to form., Comment: Accepted by ApJ, 46 pages, 12 figures