- ID:
- ivo://CDS.VizieR/J/MNRAS/460/4150
- Title:
- JCMT Gould Belt Survey: W40 complex
- Short Name:
- J/MNRAS/460/4150
- Date:
- 14 Jan 2022 11:14:19
- Publisher:
- CDS
- Description:
- We present SCUBA-2 450{mu}m and 850{mu}m observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, {beta}=1.8, and a beam convolution kernel to achieve a common 14.8-arcsec resolution. We identify 82 clumps ranging between 10 and 36K with a mean temperature of 20+/-3K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 10^5^cm^-3^. 13 of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70{mu}m images. From JCMT HARP observations of the ^12^CO 3-2 line, we find contamination of the 850{mu}m band of up to 20 per cent. We investigate the free-free contribution to SCUBA-2 bands from large-scale and ultracompact HII regions using archival VLA data and find the contribution is limited to individual stars, accounting for 9 per cent of flux per beam at 450{mu}m or 12 per cent at 850{mu}m in these cases. We conclude that radiative heating has potentially influenced the formation of stars in the Dust Arc sub-region, favouring Jeans stable clouds in the warm east and fragmentation in the cool west.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/2163
- Title:
- JCMT Plane Survey. first complete data release
- Short Name:
- J/MNRAS/469/2163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first data release of the James Clerk Maxwell Telescope Plane Survey (JPS), the JPS Public Release 1. JPS is an 850-{mu}m continuum survey of six fields in the northern inner Galactic plane in a longitude range of l=7{deg}-63{deg}, made with the Submillimetre Common-User Bolometer Array 2. This first data release consists of emission maps of the six JPS regions with an average pixel-to-pixel noise of 7.19mJy/beam, when smoothed over the beam, and a compact source catalogue containing 7813 sources. The 95 per cent completeness limits of the catalogue are estimated at 0.04Jy/beam and 0.3Jy for the peak and integrated flux densities, respectively. The emission contained in the compact source catalogue is 42+/-5 per cent of the total and, apart from the large-scale (greater than 8 arcmin) emission, there is excellent correspondence with features in the 500-{mu}m Herschel maps. We find that, with two-dimensional matching, 98 {\pm} 2 per cent of sources within the fields centred at l=20{deg}, 30{deg}, 40{deg} and 50{deg} are associated with molecular clouds, with 91+/-3 per cent of the l=30{deg} and 40{deg} sources associated with dense molecular clumps. Matching the JPS catalogue to Herschel 70-{mu}m sources, we find that 38+/-1 per cent of sources show evidence of ongoing star formation. The JPS Public Release 1 images and catalogue will be a valuable resource for studies of star formation in the Galaxy and the role of environment and spiral arms in the star formation process.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/4264
- Title:
- JCMT Plane Survey: l=30{deg} field
- Short Name:
- J/MNRAS/453/4264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present early results from the JCMT (James Clerk Maxwell Telescope) Plane Survey (JPS), which has surveyed the northern inner Galactic plane between longitudes l=7{deg} and l=63{deg} in the 850-{mu}m continuum with SCUBA-2 (Submm Common-User Bolometer Array 2), as part of the JCMT Legacy Survey programme. Data from the l=30{deg} survey region, which contains the massive-star-forming regions W43 and G29.96, are analysed after approximately 40 percent of the observations had been completed. The pixel-to-pixel noise is found to be 19mJy/beam after a smooth over the beam area, and the projected equivalent noise levels in the final survey are expected to be around 10mJy/beam. An initial extraction of compact sources was performed using the FellWalker method, resulting in the detection of 1029 sources above a 5{sigma} surface-brightness threshold. The completeness limits in these data are estimated to be around 0.2Jy/beam (peak flux density) and 0.8 Jy (integrated flux density) and are therefore probably already dominated by source confusion in this relatively crowded section of the survey. The flux densities of extracted compact sources are consistent with those of matching detections in the shallower APEX (Atacama Pathfinder Experiment) Telescope Large Area Survey of the Galaxy (ATLASGAL) survey. We analyse the virial and evolutionary state of the detected clumps in the W43 star-forming complex and find that they appear younger than the Galactic-plane average.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/492
- Title:
- JCMT/SCUBA2 objects in COSMOS and UDS fields
- Short Name:
- J/MNRAS/469/492
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present physical properties [redshifts (z), star-formation rates (SFRs) and stellar masses (M*)] of bright (S_850_>=4mJy) submm galaxies in the ~=2deg^2^ COSMOS and UDS fields selected with SCUBA-2/JCMT. We complete the galaxy identification process for all (~=2000) S/N>=3.5 850-{mu}m sources, but focus our scientific analysis on a high-quality subsample of 651 S/N>=4 sources with complete multiwavelength coverage including 1.1-mm imaging. We check the reliability of our identifications, and the robustness of the SCUBA-2 fluxes by revisiting the recent ALMA follow-up of 29 sources in our sample. Considering >4mJy ALMA sources, our identification method has a completeness of ~=86 per cent with a reliability of ~=92 per cent, and only ~=15-20 per cent of sources are significantly affected by multiplicity (when a secondary component contributes >1/3 of the primary source flux). The impact of source blending on the 850-{mu}m source counts as determined with SCUBA-2 is modest; scaling the single-dish fluxes by ~=0.9 reproduces the ALMA source counts. For our final SCUBA-2 sample, we find median z=2.40^+0.10^_-0.04_, SFR=287+/-6M_{sun}_/yr and log(M*/M_{sun)_=11.12+/-0.02 (the latter for 349/651 sources with optical identifications). These properties clearly locate bright submm galaxies on the high-mass end of the 'main sequence' of star-forming galaxies out to z~= 6, suggesting that major mergers are not a dominant driver of the high-redshift submm-selected population. Their number densities are also consistent with the evolving galaxy stellar mass function. Hence, the submm galaxy population is as expected, albeit reproducing the evolution of the main sequence of star-forming galaxies remains a challenge for theoretical models/simulations.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A127
- Title:
- Jet-driven outflow in ESO 420-G13
- Short Name:
- J/A+A/633/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A prominent jet-driven outflow of CO(2-1) molecular gas is found along the kinematic minor axis of the Seyfert 2 galaxy ESO 420-G13, at a distance of 340-600pc from the nucleus. The wind morphology resembles a characteristic funnel shape, formed by a highly collimated filamentary emission at the base, likely tracing the jet propagation through a tenuous medium, until a bifurcation point at 440pc where the jet hits a dense molecular core and shatters, dispersing the molecular gas into several clumps and filaments within the expansion cone. We also trace the jet in ionised gas within the inner ~340pc using the [NeII]12.8um line emission, where the molecular gas follows a circular rotation pattern. The wind outflow carries a mass of ~8x10^6^M_{sun}_ at an average wind projected speed of ~160km/s, which implies a mass outflow rate of ~14M_{sun}_/yr. Based on the structure of the outflow and the budget of energy and momentum, we discard radiation pressure from the active nucleus, star formation, and supernovae as possible launching mechanisms. ESO 420-G13 is the second case after NGC 1377 where the presence of a previously unknown jet is revealed due to its interaction with the interstellar medium, suggesting that unknown jets in feeble radio nuclei might be more common than expected. Two possible jet-cloud configurations are discussed to explain the presence of an outflow at such distance from the AGN. The outflowing gas will likely not escape, thus a delay in the star formation rather than quenching is expected from this interaction, while the feedback effect would be confined within the central few hundred parsecs of the galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A1
- Title:
- JHK photometry of CBJC 8 sources
- Short Name:
- J/A+A/525/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The infrared cluster CBJC 8 is associated with a 6.7GHz methanol maser and a compact radio-continuum source, G85.40-0.00. It is located at a distance of about 8kpc. The aim is to study the characteristics of this distant and compact embedded cluster and derive the properties of its stellar population. We present new ground-based near- and mid-imaging observations of this region. The calibrated images were analysed together with archive Spitzer IRAC images. Based on the discovery of a considerable fraction of embedded sources with infrared excess emission that are concentrated within a radius around 16arcsec centred near the position of the compact HII region G85.40-0.00, we were able to confirm the presence of a very young embedded cluster. It was found to contain more than 58 members brighter than M_K_=2.6, with two-thirds of them showing significant near- or mid-IR excess emission. Spectral energy distributions and extrapolated total luminosities are presented for nine sources with large mid-infrared excesses that were measured in all four IRAC bands. For the brightest of these, G8540A, which is associated with a methanol maser and a compact HII region, we fitted a model of an infalling envelope plus disc plus central star to its observed 1.6 to 850um fluxes to get an idea of its physical properties. We also report the presence of a single 2.12um molecular hydrogen line emission knot near the centre of the cluster, suggesting the outflow activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/707/1201
- Title:
- LABOCA ECDFS Submillimeter Survey (LESS)
- Short Name:
- J/ApJ/707/1201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sensitive 870um survey of the Extended Chandra Deep Field South (ECDFS) combining 310hr of observing time with the Large Apex BOlometer Camera (LABOCA) on the APEX telescope. The LABOCA ECDFS Submillimetre Survey (LESS) covers the full 30'x30' field size of the ECDFS and has a uniform noise level of {sigma}_870um_~1.2mJy/beam. LESS is thus the largest contiguous deep submillimeter survey undertaken to date. The noise properties of our map show clear evidence that we are beginning to be affected by confusion noise. We present a catalog of 126 submillimeter galaxies (SMGs) detected with a significance level above 3.7{sigma}, at which level we expect five false detections given our map area of 1260arcmin^2^.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A53
- Title:
- LABOCA 870um images of evolved stars
- Short Name:
- J/A+A/513/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During their evolution, Asymptotic Giant Branch (AGB) stars experience a high mass-loss which leads to the formation of a circumstellar envelope (CSE) of dust and gas. The mass loss process is the most important phenomenon during this evolutionary stage. In order to understand it, it is important to study the physical parameters of the CSE. The emission of the CSE in the (sub)millimetre range is dominated by the dust continuum. This means that (sub)millimetre observations are a key tool in tracing the dust and improving our knowledge of the mass-loss process. We analysed new sub-millimetre observations of 9 evolved stars in order to constrain the CSE physical parameters. The data were taken by the new APEX bolometer LABoCa. The fluxes at 870 um are derived and the extended emission is investigated. We computed the spectral energy distribution (SEDs) with the 1D radiative transfer code DUSTY, which we compared to literature data. Grain properties were calculated with both a spherical grains distribution and a continuous distribution of ellipsoids (CDE), and a comparison between the two is drawn. Synthetic surface brightness maps were derived from the modelling and were compared to the LABoCa brightness maps. We detected the presence of extended emission around four stars. Physical parameters of the circumstellar envelope were derived from SED modelling, like the dust chemical composition, the dust condensation temperature and the total mass of the envelope.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A101
- Title:
- LABOCA 870um mapping of 4 Galactic plane fields
- Short Name:
- J/A+A/542/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Imaging surveys of dust emission at (sub)millimetre wavelengths provide a powerful tool for studying molecular clouds and the early stages of star formation. Through submm dust continuum mapping, we attempt to search for genuine infrared-dark clouds (IRDCs) and precursors to massive stars and stellar clusters in the Galactic plane, and to determine their basic physical properties. We have mapped four selected fields of about 0.5degx0.5deg that contain Spitzer 8-um dark regions with LABOCA at 870um. Selected positions in the fields were observed in C^17^O(2-1) to obtain kinematic information. The obtained LABOCA maps are used in conjunction with the Spitzer IR images.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A140
- Title:
- Large Quasar Astrometric Catalogue 4, LQAC-4
- Short Name:
- J/A+A/614/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From an astrometric point of view, quasars constitute the best and almost ideal reference objects in the celestial sphere, with a priori no significant proper motion. Since the third release of the Large Quasar Astrometric Catalogue (LQAC-3, Cat. J/A+A/583/A75), a large number of quasars have been discovered, in particular those coming from the DR12Q release of the SDSS (Paris et al., 2017, Cat. VII/279). Moreover, for cross-matched objects, we have taken advantage of the very accurate determinations of the quasars identified within the recent Gaia DR1 catalogue (2018, Cat. I/345). Following the same procedure as in the three previous releases of the LQAC, our aim is to compile the large majority of all the quasars recorded so far. Our goal is to record their best coordinates and substantial information concerning their physical properties such as the redshift as well as multi-bands apparent and absolute magnitudes. Emphasis is given to the results of the cross-matches with the Gaia DR1 catalogue. New quasars coming from the DR12Q release were cross-matched with the precedent LQAC-3 compilation with a 1" search radius, in order to add the objects without counterpart to the LQAC-4 compilation. A similar cross-match was done with Gaia DR1 to identify the known quasars detected by Gaia. This enables one to improve significantly the positioning of these objects, and in parallel to study the astrometric performance of the individual catalogues of the LQAC-4 compilation. Finally, a new method was used to determine absolute magnitudes. Our final catalogue, called LQAC-4, contains 443 725 objects. This is roughly 37.82% more than the number of objects recorded in the LQAC-3. Among them, 249071 were found in common with the Gaia DR1, with a 1" search radius. That corresponds to 56.13% of the whole population in the compilation. The LQAC-4 delivers to the astronomical community a nearly complete catalogue of spectroscopically confirmed quasars (including a small proportion of compact AGNs), with the aim of giving their best equatorial coordinates with respect to the ICRF2 and with exhaustive additional information. For more than 50% of the sample, these coordinates come from the very recent Gaia DR1.
