- 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.
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Search Results
- 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/601/A80
- Title:
- LABOCA 345GHz observations of Sgr A*
- Short Name:
- J/A+A/601/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a statistical analysis of the 345GHz submillimeter (submm) and 100GHz radio flux density distribution of Sagittarius A* (Sgr A*). The submm data set consists of 345GHz data obtained from different Large Apex Bolometer Camera (LABOCA) campaigns between 2008 and 2014, and additional literature data from 2004 to 2009 at comparable wavelengths. The radio observations were carried out with the Australia Telescope Compact Array (ATCA) between 2010 and 2014. We used a combined maximum likelihood estimator (MLE) and Kolmogorov-Smirnov (KS) statistics method to test for a possible power-law distribution in the high flux density excursions (flares) at both wavebands. We find that both flux density distributions can be described by a shifted power-law of the form p(x){prop.to}(x-S)^-{alpha}^ with {alpha}~4 (submm: {alpha}=4.0+/-1.7, radio: {alpha}=4.7+/-0.8). The same power-law index was previously found for the near-infrared (NIR) flux density distribution. These results may strengthen our preferred flare emission model: a combined synchrotron self-Compton (SSC) and adiabatically expanding self-absorbed synchrotron blob model where the flaring activity across all wavebands stem from the same source components and the variable emission can be described by a single state red noise process. Within the framework of the expanding blob model the similarity of the radio and the submm flux density distribution may also narrow down possible initial synchrotron turnover {nu}_0_ to be mainly around 350GHz and possible expansion velocities v_exp_ to be predominantly around 0.01c.
- 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/463/1008
- Title:
- LDN 1495 SCUBA-2 and Herschel data
- Short Name:
- J/MNRAS/463/1008
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of Submillimetre Common User Bolometer Array-2 (SCUBA-2) 850-{mu}m and Herschel 70-500-{mu}m observations of the L1495 filament in the Taurus Molecular Cloud with the goal of characterizing the SCUBA-2 Gould Belt Survey (GBS) data set. We identify and characterize starless cores in three data sets: SCUBA-2 850-{mu}m, Herschel 250-{mu}m, and Herschel 250-{mu}m spatially filtered to mimic the SCUBA-2 data. SCUBA-2 detects only the highest-surface-brightness sources, principally detecting protostellar sources and starless cores embedded in filaments, while Herschel is sensitive to most of the cloud structure, including extended low-surface-brightness emission. Herschel detects considerably more sources than SCUBA-2 even after spatial filtering. We investigate which properties of a starless core detected by Herschel determine its detectability by SCUBA-2, and find that they are the core's temperature and column density (for given dust properties). For similar-temperature cores, such as those seen in L1495, the surface brightnesses of the cores are determined by their column densities, with the highest-column-density cores being detected by SCUBA-2. For roughly spherical geometries, column density corresponds to volume density, and so SCUBA-2 selects the densest cores from a population at a given temperature. This selection effect, which we quantify as a function of distance, makes SCUBA-2 ideal for identifying those cores in Herschel catalogues that are closest to forming stars. Our results can now be used by anyone wishing to use the SCUBA-2 GBS data set.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1479
- Title:
- LESS photometric redshift survey
- Short Name:
- J/MNRAS/415/1479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive photometric redshifts from 17-band optical to mid-infrared photometry of 78 robust radio, 24um and Spitzer IRAC counterparts to 72 of the 126 submillimetre galaxies (SMGs) selected at 870um by LABOCA observations in the Extended Chandra Deep Field-South (ECDF-S). We test the photometric redshifts of the SMGs against the extensive archival spectroscopy in the ECDF-S.
250. L1642 Herschel maps
- ID:
- ivo://CDS.VizieR/J/A+A/563/A125
- Title:
- L1642 Herschel maps
- Short Name:
- J/A+A/563/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- L1642 is one of the two high galactic latitude (|b|>30{deg}) clouds confirmed to have active star formation. We examine the properties of this cloud, especially the large-scale structure, dust properties, and compact sources at different stages of star formation. We present high-resolution far-infrared and submillimetre observations with the Herschel and AKARI satellites and millimetre observations with the AzTEC/ASTE telescope, which we combined with archive data from near- and mid-infrared (2MASS, WISE) to millimetre wavelength observations (Planck).