We present the Multi-Array Galactic Plane Imaging Survey (MAGPIS), which maps portions of the first Galactic quadrant with an angular resolution, sensitivity, and dynamic range that surpass existing radio images of the Milky Way by more than an order of magnitude. The source detection threshold at 20cm is in the range 12mJy over the 85% of the survey region (5{deg}<l<32{deg}, |b|<0.8{deg}) not covered by bright extended emission; the angular resolution is ~6". We catalog over 3000 discrete sources (diameters mostly <30") and present an atlas of ~400 diffuse emission regions. New and archival data at 90cm for the whole survey area are also presented. Comparison of our catalogs and images with the Midcourse Space Experiment mid-infrared data allows us to provide preliminary discrimination between thermal and nonthermal sources. We identify 49 high-probability supernova remnant candidates, increasing by a factor of 7 the number of known remnants with diameters smaller than 5' in the survey region; several are pulsar wind nebula candidates and/or very small diameter remnants (D<45").
We present the first results from the MALT-45 (Millimetre Astronomer's Legacy Team-45GHz) Galactic Plane survey. We have observed 5 square degrees (l=330{deg}-335{deg}, b=+/-0.5{deg}) for spectral lines in the 7mm band (42-44 and 48-49GHz), including CS (1-0), class I CH_3_OH masers in the 7(0,7)-6(1,6) A^+^ transition and SiO (1-0) v=0,1,2,3. MALT-45 is the first unbiased, large-scale, sensitive spectral line survey in this frequency range. In this paper, we present data from the survey as well as a few intriguing results; rigorous analyses of these science cases are reserved for future publications. Across the survey region, we detected 77 class I CH_3_OH masers, of which 58 are new detections, along with many sites of thermal and maser SiO emission and thermal CS. We found that 35 class I CH_3_OH masers were associated with the published locations of class II CH_3_OH, H_2_O and OH masers but 42 have no known masers within 60 arcsec. We compared the MALT-45 CS with NH_3_ (1,1) to reveal regions of CS depletion and high opacity, as well as evolved star-forming regions with a high ratio of CS to NH_3_. All SiO masers are new detections, and appear to be associated with evolved stars from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). Generally, within SiO regions of multiple vibrational modes, the intensity decreases as v=1, 2, 3, but there are a few exceptions where v=2 is stronger than v=1.
The Millimetre Astronomy Legacy Team 90GHz survey aims to characterise the physical and chemical evolution of high-mass clumps. Recently completed, it mapped 90GHz line emission towards 3246 high-mass clumps identified from the ATLASGAL 870um Galactic plane survey. By utilising the broad frequency coverage of the Mopra telescope's spectrometer, maps in 16 different emission lines were simultaneously obtained. Here, we describe the first catalogue of the detected line emission, generated by Gaussian profile fitting to spectra extracted towards each clumps' 870um dust continuum peak. Synthetic spectra show that the catalogue has a completeness of >95%, a probability of a false-positive detection of <0.3%, and a relative uncertainty in the measured quantities of <20% over the range of detection criteria. The detection rates are highest for the (1-0) transitions of HCO^+^, HNC, N_2_H^+^, and HCN (~77-89%). Almost all clumps (~95%) are detected in at least one of the molecular transitions, just over half of the clumps (~53%) are detected in four or more of the transitions, while only one clump is detected in 13 transitions. We find several striking trends in the ensemble of properties for the different molecular transitions when plotted as a function of the clumps' evolutionary state as estimated from Spitzer mid-IR images, including (1) HNC is relatively brighter in colder, less evolved clumps than those that show active star formation, (2) N2H+ is relatively brighter in the earlier stages, (3) that the observed optical depth decreases as the clumps evolve, and (4) the optically thickest HCO^+^ emission shows a 'blue-red asymmetry' indicating overall collapse that monotonically decreases as the clumps evolve. This catalogue represents the largest compiled database of line emission towards high-mass clumps and is a valuable data set for detailed studies of these objects.
We detail interferometric observations of 44GHz class I methanol masers detected by MALT-45 (a 7mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 maser spots across 77 maser sites. Using high-resolution positions, we compare the class I CH_3_OH masers to other star formation maser species, including CS (1-0), SiO v=0 and the H53{alpha} radio-recombination line. Comparison between the cross- and auto-correlated data has allowed us to also identify quasi-thermal emission in the 44GHz class I methanol maser line. We find that the majority of class I methanol masers have small spatial and velocity ranges (<0.5pc and <5km/s), and closely trace the systemic velocities of associated clouds. Using 870{mu}m dust continuum emission from the ATLASGAL survey, we determine clump masses associated with class I masers, and find that they are generally associated with clumps between 1000 and 3000M_{sun}_. For each class I methanol maser site, we use the presence of OH masers and radio recombination lines to identify relatively evolved regions of high-mass star formation; we find that maser sites without these associations have lower luminosities and preferentially appear towards dark infrared regions.
Using molecular-line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have estimated kinematic distances to 1905 molecular clumps identified in the ATLASGAL 870 {mu}m continuum survey over the longitude range 295{deg}<l<350{deg}. The clump velocities were determined using a flux-weighted average of the velocities obtained from Gaussian fits to the HCO^+^, HNC, and N_2_H^+^ (1-0) transitions. The near/far kinematic distance ambiguity was addressed by searching for the presence or absence of absorption or self-absorption features in 21 cm atomic hydrogen spectra from the Southern Galactic Plane Survey. Our algorithm provides an estimation of the reliability of the ambiguity resolution. The Galactic distribution of the clumps indicates positions where the clumps are bunched together, and these locations probably trace the locations of spiral arms. Several clumps fall at the predicted location of the far side of the Scutum-Centaurus arm. Moreover, a number of clumps with positive radial velocities are unambiguously located on the far side of the Milky Way at galactocentric radii beyond the solar circle. The measurement of these kinematic distances, in combination with continuum or molecular-line data, now enables the determination of fundamental parameters such as mass, size, and luminosity for each clump.
We describe a pilot survey conducted with the Mopra 22m radio telescope in preparation for the Millimeter Astronomy Legacy Team Survey at 90GHz (MALT90). We identified 182 candidate dense molecular clumps using six different selection criteria and mapped each source simultaneously in 16 different lines near 90GHz. We present a summary of the data and describe how the results of the pilot survey shaped the design of the larger MALT90 survey. We motivate our selection of target sources for the main survey based on the pilot detection rates and demonstrate the value of mapping in multiple lines simultaneously at high spectral resolution.
We present maps from our MAMBO 1.2mm wavelength dust emission survey of nearby (<500pc) dense starless and star-forming cores. This data was collected to study evolutionary trends among the dense cores and the associated young stellar objects. This survey was specifically designed to complement Spitzer Space Telescope imaging of these regions. The maps are unusually sensitive and rich in structure.
We describe the sample design for the SDSS-IV MaNGA survey and present the final properties of the main samples along with important considerations for using these samples for science. Our target selection criteria were developed while simultaneously optimizing the size distribution of the MaNGA integral field units (IFUs), the IFU allocation strategy, and the target density to produce a survey defined in terms of maximizing signal-to-noise ratio, spatial resolution, and sample size. Our selection strategy makes use of redshift limits that only depend on i-band absolute magnitude (M_i_), or, for a small subset of our sample, M i and color (NUV-i). Such a strategy ensures that all galaxies span the same range in angular size irrespective of luminosity and are therefore covered evenly by the adopted range of IFU sizes. We define three samples: the Primary and Secondary samples are selected to have a flat number density with respect to M_i_ and are targeted to have spectroscopic coverage to 1.5 and 2.5 effective radii (Re), respectively. The Color-Enhanced supplement increases the number of galaxies in the low-density regions of color-magnitude space by extending the redshift limits of the Primary sample in the appropriate color bins. The samples cover the stellar mass range 5x10^8^<=M*<=3x10^11^M_{sun}/h^2^ and are sampled at median physical resolutions of 1.37 and 2.5kpc for the Primary and Secondary samples, respectively. We provide weights that will statistically correct for our luminosity and color-dependent selection function and IFU allocation strategy, thus correcting the observed sample to a volume-limited sample.
We present a map of the diffuse ultraviolet cosmic background in two wavelength bands (FUV: 1530{AA} and NUV: 2310{AA}) over almost 75% of the sky using archival data from the Galaxy Evolution Explorer (GALEX) mission. Most of the diffuse flux is due to dust-scattered starlight and follows a cosecant law with slopes of 545 photons/cm^2^/s/sr/{AA} and 433 photons/cm^2^/s/sr/{AA} in the FUV and NUV bands, respectively. There is a strong correlation with the 100um Infrared Astronomy Satellite (IRAS) flux with an average UV/IR ratio of 300 photons/cm^2^/s/sr/{AA}/(MJy/sr) in the FUV band and that of 220 photons/cm^2^/s/sr/{AA}/(MJy/sr) in the NUV band but with significant variations over the sky. In addition to the large-scale distribution of the diffuse light, we note a number of individual features including bright spots around the hot stars Spica and Achernar.
The Macquarie/AAO/Strasbourg H{alpha} Planetary Nebula Catalogue (MASH) contains 903 new true, likely and possible Galactic Planetary Nebulae (PNe) discovered from the AAO/UKST H{alpha} survey of the southern Galactic plane. The combination of depth, resolution, uniformity, and areal coverage of the H {alpha}survey has opened up an hitherto unexplored region of parameter space permitting the detection of this significant new PN sample. This catalogue includes also the spectra of the PNe as FITS files (in the "sp" subdirectory), and a gallery of images created as a combination of the H{alpha} and short red images of the survey. The second part, MASH-II (table mash2.dat) consists of over 300 true, likely and possible new Galactic PNe found after re-examination of the entire AAO/UKST H{alpha} survey of the Southern Galactic Plane in digital form. Over 240 of these new candidates were confirmed as bona fide PNe on the basis of spectroscopic observations. The spectra of this supplement will be available in the future.