We describe the motivation, design and implementation of the CORNISH survey, an arcsecond resolution radio continuum survey of the inner Galactic plane at 5 GHz using the Karl G. Jansky Very Large Array (VLA). It is a blind survey co-ordinated with t
he northern Spitzer GLIMPSE I region covering 10 deg < l < 65 deg and |b| < 1 deg at similar resolution. We discuss in detail the strategy that we employed to control the shape of the synthesised beam across this survey that covers a wide range of fairly low declinations. Two snapshots separated by 4 hours in hour angle kept the beam elongation to less that 1.5 over 75% of the survey area and less than 2 over 98% of the survey. The prime scientific motivation is to provide an unbiased survey for ultra-compact HII regions to study this key phase in massive star formation. A sensitivity around 2 mJy will allow the automatic distinction between radio loud and quiet mid-IR sources found in the Spitzer surveys. This survey has many legacy applications beyond star formation including evolved stars, active stars and binaries, and extragalactic sources. The CORNISH survey for compact ionized sources complements other Galactic plane surveys that target diffuse and non-thermal sources as well as atomic and molecular phases to build up a complete picture of the ISM in the Galaxy.
The supersonic stellar and disk winds possessed by massive young stellar objects will produce shocks when they collide against the interior of a pre-existing bipolar cavity (resulting from an earlier phase of jet activity). The shock heated gas emits
thermal X-rays which may be observable by spaceborne observa- tories such as the Chandra X-ray Observatory. Hydrodynamical models are used to explore the wind-cavity interaction. Radiative transfer calculations are performed on the simulation output to produce synthetic X-ray observations, allowing constraints to be placed on model parameters through comparisons with observations. The model reveals an intricate interplay between the inflowing and outflowing material and is successful in reproducing the observed X-ray count rates from massive young stellar objects.
We present the results of a programme of scanning and mapping observations of astronomical masers and Jupiter designed to characterise the performance of the Mopra Radio Telescope at frequencies between 16-50 GHz using the 12-mm and 7-mm receivers. W
e use these observations to determine the telescope beam size, beam shape and overall telescope beam efficiency as a function of frequency. We find that the beam size is well fit by $lambda$/$D$ over the frequency range with a correlation coefficient of ~90%. We determine the telescope main beam efficiencies are between ~48-64% for the 12-mm receiver and reasonably flat at ~50% for the 7-mm receiver. Beam maps of strong H$_2$O (22 GHz) and SiO masers (43 GHz) provide a means to examine the radial beam pattern of the telescope. At both frequencies the radial beam pattern reveals the presence of three components, a central `core, which is well fit by a Gaussian and constitutes the telescopes main beam, and inner and outer error beams. At both frequencies the inner and outer error beams extend out to approximately 2 and 3.4 times the full-width half maximum of the main beam respectively. Sources with angular sizes a factor of two or more larger than the telescope main beam will couple to the main and error beams, and therefore the power contributed by the error beams needs to be considered. From measurements of the radial beam power pattern we estimate the amount of power contained in the inner and outer error beams is of order one-fifth at 22 GHz rising slightly to one-third at 43 GHz.
We discuss VLTI AMBER and MIDI interferometry in addition to single-dish Subaru observations of massive young stellar objects. The observations probe linear size scales between 10 to 1000 AU for the average distance of our sources.
The UKIDSS Galactic Plane Survey (GPS) is one of the five near infrared Public Legacy Surveys that are being undertaken by the UKIDSS consortium, using the Wide Field Camera on the United Kingdom Infrared Telescope. It is surveying 1868 sq.deg. of th
e northern and equatorial Galactic plane at Galactic latitudes -5<b<5 in the J, H and K filters and a ~200 sq.deg. area of the Taurus-Auriga-Perseus molecular cloud complex in these three filters and the 2.12 um (1-0) H_2 filter. It will provide data on ~2 billion sources. Here we describe the properties of the dataset and provide a users guide for its exploitation. We also present brief Demonstration Science results from DR2 and from the Science Verification programme. These results illustrate how GPS data will frequently be combined with data taken in other wavebands to produce scientific results. The Demonstration Science includes studies of: (i) the star formation region G28.983-0.603, cross matching with Spitzer-GLIMPSE data to identify YSOs; (ii) the M17 nebula; (iii) H_2 emission in the rho Ophiuchi dark cloud; (iv) X-ray sources in the Galactic Centre; (v) external galaxies in the Zone of Avoidance; (vi) IPHAS-GPS optical-infrared spectrophotometric typing. (abridged).
Context: The Red MSX Source (RMS) survey is an ongoing multi-wavelength observational programme designed to return a large, high-resolution mid-infrared colour-selected sample of massive young stellar objects. Aims: A critical part of our follow-up
programme is to conduct 13CO molecular line observations in order to determine kinematic distances to all of our MYSO candidates. These distances will allow us to identify and remove nearby low-mass YSOs and help in identifying evolved stars which are weak CO emitters. Method: We have used the 15 m James Clerk Maxwell Telescope (JCMT), the 13.7 m telescope of the Purple Mountain Observatory (PMO), the 20 m Onsala telescope and the 22m Mopra telescope to conduct molecular line observations towards 508 MYSOs candidates located in the 1st and 2nd Quadrants. Results: We detect 13CO emission towards 780 RMS sources which corresponds to approximately 84% of those observed (911). A total of 2595 emission components are detected above 3sigma level (typically T^*_{rm{A}} > 0.3K), with multiple components being observed towards the majority of these sources -- 520 sources (~56%) -- with an average of ~4 molecular clouds detected along each line of sight. We have used archival CS (J=2-1) and maser velocities to resolve the component multiplicity towards 175 sources (~20%) and have derived a criterion which is used to identify the most likely component for a further 191 multiple component sources. Combined with the single component detections we have obtained unambiguous kinematic velocities for 638 of the 780 MYSOs candidates towards which CO is detected (~80% of the detections). Using the Galactic rotation curve we calculate kinematic distances for all detected components.
Here we describe the Red MSX Source (RMS) survey which is the largest, systematic, galaxy-wide search for massive young stellar objects (MYSOs) yet undertaken. Mid-IR bright point sources from the MSX satellite survey have been followed-up with groun
d-based radio, millimetre, and infrared observations to identify the contaminating sources and characterise the MYSOs and UCHII regions. With the initial classification now complete the distribution of sources in the galaxy will be discussed, as well as some programmes being developed to exploit our sample.
