- ID:
- ivo://CDS.VizieR/J/A+A/474/891
- Title:
- 13CO observations of YSOs in South Gal. plane
- Short Name:
- J/A+A/474/891
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Red MSX Source (RMS) survey is an ongoing multi-wavelength observational programme designed to return a large, well-selected sample of massive young stellar objects (MYSOs). We have identified ~2000 MYSOs candidates located within our Galaxy by comparing the colours of MSX and 2MASS point sources to those of known MYSOs. The aim of our follow-up observations is to identify other contaminating objects such as ultra compact (UC) HII regions, evolved stars and planetary nebulae (PNe) and distinguish between genuine MYSOs and nearby low-mass YSOs. A critical part of our follow-up programme is to conduct ^13^CO molecular line observations in order to determine kinematic distances to all of our MYSO candidates. These distances will be used in combination with far-IR and (sub)millimetre fluxes to determine bolometric luminosities which will allow us to identify and remove nearby low-mass YSOs. In addition these molecular line observations will help in identifying evolved stars which are weak CO emitters. We have used the 22m Mopra telescope, the 15m JCMT and the 20m Onsala telescope to conduct molecular line observations towards 854 MYSOs candidates located in the 3rd and 4th quadrants. These observations have been made at the J=1-0 (Mopra and Onsala) and J=2-1 (JCMT) rotational transition frequency of ^13^CO molecules and have a spatial resolution of ~20"-40", a sensitivity of T_A_^*^~0.1K and a velocity resolution of ~0.2km/s.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/798/L27
- Title:
- CO obs. of molecular clouds in the 2nd quadrant
- Short Name:
- J/ApJ/798/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Combining H I data from the Canadian Galactic Plane Survey and CO data from the Milky Way Imaging Scroll Painting project (MWISP), we have identified a new segment of a spiral arm between Galactocentric radii of 15 and 19kpc that apparently lies beyond the Outer Arm in the second Galactic quadrant. Over most of its length, the arm is 400-600pc thick in z. The new arm appears to be the extension of the distant arm recently discovered by Dame & Thaddeus (2011ApJ...734L..24D) as well as the Scutum-Centaurus Arm into the outer second quadrant. Our current survey identified a total of 72 molecular clouds with masses on the order of 10^2^-10^4^M_{sun}_ that probably lie in the new arm. When all of the available data from the CO molecular clouds are fit, the best-fitting spiral model gives a pitch angle of 9.3{deg}+/-0.7{deg}.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/7
- Title:
- CO obs. of the outer arm in the 2nd quadrant
- Short Name:
- J/ApJS/224/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l=[100,150]{deg}, b=[-3,5]{deg} has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas --this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115GHz ^12^CO(1-0) data of MWISP at the LSR velocity ~[-100,-60]km/s and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ~3.1x10^6^M_{sun}__. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ~13.1{deg}. Besides combining both the CO data from MWISP and the 21cm HI data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.
- ID:
- ivo://CDS.VizieR/J/A+A/472/187
- Title:
- 12CO outflows towards submm cores in Perseus
- Short Name:
- J/A+A/472/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for outflows towards 51 submillimetre cores in Perseus. With consistently derived outflow properties from a large homogeneous dataset within one molecular cloud we can investigate further the mass dependence and time evolution of protostellar mass loss. Of the 51 cores, 37 show broad linewings indicative of molecular outflows. In 13 cases, the linewings could be due to confusion with neighbouring flows but 9 of those sources also have near-infrared detections confirming their protostellar nature. The total fraction of protostars in our sample is 65%. All but four outflow detections are confirmed as protostellar by Spitzer IR detections and only one Spitzer source has no outflow, showing that outflow maps at this sensitivity are equally good at identifying protostars as Spitzer. Outflow momentum flux correlates both with source luminosity and with core mass but there is considerable scatter even within this one cloud despite the homogeneous dataset. We fail to confirm the result of Bontemps et al. (1996A&A...311..858B) that Class I sources show lower momentum fluxes on average than Class 0 sources, with a KS test showing a significant probability that the momentum fluxes for both Class 0s and Class Is are drawn from the same distribution. We find that outflow power may not show a simple decline between the Class 0 to Class I stages. Our sample includes low momentum flux, low-luminosity Class 0 sources, possibly at a very early evolutionary stage. If the only mass loss from the core were due to outflows, cores would last for 10^5^-10^8^years, longer than current estimates of 1.5-4x10^5^years for the mean lifetime for the embedded phase. Additional mechanisms for removing mass from protostellar cores may be necessary.
- ID:
- ivo://CDS.VizieR/VII/50
- Title:
- CO Radial Velocities Toward Galactic H II Regions
- Short Name:
- VII/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains machine-readable versions of the "Catalog of CO Radial Velocities Toward Galactic HII Regions" (Blitz et al. 1982) and the "Catalog of Carbon Monoxide Observations of Southern Hemisphere HII Regions" (Gillespie et al. 1977) in two separate files. The former is a catalog of 242 molecular cloud complexes that are associated with optical HII regions and includes source names, coordinates, CO radial velocities, antenna temperatures and full width at half-maximum at the position of the strongest CO emission, references for the observations, distances to the stars exciting the HII regions, and optical diameters of the HII regions. The latter is the first CO survey of the southern sky; it was made using the Anglo-Australian 3.9-m optical telescope at 115GHz (2.6-mm wavelength) with a hot-electron bolometer receiver located at the Coude focus. The data were collected during two observing periods (September 1975, April 1976) and include designations, coordinates, median values for the velocities, and distances to the stars exciting the HII regions.
- ID:
- ivo://CDS.VizieR/J/A+A/407/899
- Title:
- Core dominance in extragalactic radio sources
- Short Name:
- J/A+A/407/899
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, based on a paper by Liu and Zhang (2002, Cat. <J/A+A/381/757>), we have chosen a sample of 542 extragalactic sources (27 BL Lac objects, 300 galaxies (radio galaxies and Seyfert galaxies), and 215 quasars), for which we have calculated the core-dominance parameters and investigated the relation between core-dominance parameter and the core and extended luminosities. The core-dominance parameter of galaxies is smaller than that in quasars, which is smaller than that in BL Lac objects.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2541
- Title:
- Core of the Shapley supercluster at 1.4GHz
- Short Name:
- J/AJ/130/2541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The core of the Shapley supercluster (A3556, A3558, SC 1327-312, SC 1329-313, and A3562) is an ideal region in which to study the effects of cluster mergers on the activity of individual galaxies. This paper presents the most comprehensive radio continuum investigation of the region, relying on a 63 pointing mosaic obtained with the Very Large Array yielding an areal coverage of nearly 7{deg}^2^.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A99
- Title:
- Cores in HII regions parameters
- Short Name:
- J/A+A/611/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (HII) regions. The formation of these pockets of ionised gas are unique to the formation of high-mass stars (M>8M_{sun}_), and present an excellent opportunity to study the final stages of accretion, which could include accretion through the HII region itself. This study of the dynamics of the gas on both sides of these ionisation boundaries in very young HII regions aims to quantify the relationship between the HII regions and their immediate environments. We present high-resolution (~0.5") ALMA observations of nine HII regions selected from the Red MSX Source (RMS, Lumsden et al., Cat. J/ApJS/208/11) survey with compact radio emission and bolometric luminosities greater than 10^4^L_{sun}_. We focus on the initial presentation of the data, including initial results from the radio recombination line H29{alpha} some complementary molecules, and the 256GHz continuum emission.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A103
- Title:
- CORNISH project. III. UCHII region catalogue
- Short Name:
- J/A+A/615/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of 239 ultra-compact HII regions (UCHIIs) found in the CORNISH survey at 5GHz and 1.5-arcsec resolution in the region 10{deg}<l<65{deg}, |b|<1{deg} is presented. This is the largest complete and well-selected sample of UCHIIs to date and provides the opportunity to explore the global and individual properties of this key state in massive star formation at multiple wavelengths. The nature of the candidates was validated, based on observational properties and calculated spectral indices, and the analysis is presented in this work. The physical sizes, luminosities and other physical properties were computed by utilising literature distances or calculating the distances whenever a value was not available. The near- and mid-infrared extended source fluxes were measured and the extinctions towards the UCHIIs were computed. The new results were combined with available data at longer wavelengths and the spectral energy distributions (SEDs) were reconstructed for 177 UCHIIs. The bolometric luminosities obtained from SED fitting are presented. By comparing the radio flux densities to previous observational epochs, we find about 5% of the sources appear to be time variable. This first high-resolution area survey of the Galactic plane shows that the total number of UCHIIs in the Galaxy is ~750 - a factor of 3-4 fewer than found in previous large area radio surveys. It will form the basis for future tests of models of massive star formation.
- ID:
- ivo://CDS.VizieR/J/ApJS/205/1
- Title:
- CORNISH project. II. Source catalog
- Short Name:
- J/ApJS/205/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CORNISH (Co-Ordinated Radio 'N' Infrared Survey for High-mass star formation) project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5GHz radio continuum part of a series of multi-wavelength surveys that focus on the northern GLIMPSE region (10{deg}<l<65{deg}), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1.5" resolution Stokes I map with a root mean square noise level better than 0.4mJy/beam. Here we describe the data-processing methods and data characteristics, and present a new, uniform catalog of compact radio emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimized to detect emission on size scales up to 14" and for unresolved sources the catalog is more than 90% complete at a flux density of 3.9mJy. We have detected 3062 sources above a 7{sigma} detection limit and present their ensemble properties. The catalog is highly reliable away from regions containing poorly sampled extended emission, which comprise less than 2% of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artifacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: HII regions, planetary nebulae, and radio galaxies.
