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921. Magnetic field structure in W51A
ID:
ivo://CDS.VizieR/J/A+A/385/1014
Title:
Magnetic field structure in W51A
Short Name:
J/A+A/385/1014
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 850{mu}m imaging polarimetry of the W51A massive star forming region performed with SCUBA on the James Clerk Maxwell Telescope (JCMT) situated close to the summit of Mauna Kea, Hawaii, on the night 6 October 2000. Positions, fluxes and polarimetry of the data points shown in Fig. 1 of the paper are reported in the file table2.dat. The positional offsets are given relative to W51d (19:23:39.0, +14:31:08, J2000). All fluxes (including the Stokes Q and U parameters) are given in units of Jy/beam. The position angles give the direction of the E-vector.
922. MAGPIS 20cm survey
ID:
ivo://CDS.VizieR/J/AJ/131/2525
Title:
MAGPIS 20cm survey
Short Name:
J/AJ/131/2525
Date:
21 Oct 2021
Publisher:
CDS
Description:
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").
923. MALT-45, a 7mm survey of the southern Galaxy
ID:
ivo://CDS.VizieR/J/MNRAS/448/2344
Title:
MALT-45, a 7mm survey of the southern Galaxy
Short Name:
J/MNRAS/448/2344
Date:
21 Oct 2021
Publisher:
CDS
Description:
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.
924. MALT-45, 44 GHz class I methanol masers
ID:
ivo://CDS.VizieR/J/MNRAS/471/3915
Title:
MALT-45, 44 GHz class I methanol masers
Short Name:
J/MNRAS/471/3915
Date:
21 Oct 2021
Publisher:
CDS
Description:
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.
925. MALT90 pilot survey
ID:
ivo://CDS.VizieR/J/ApJS/197/25
Title:
MALT90 pilot survey
Short Name:
J/ApJS/197/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
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.
926. MAMBO sources near NTT Deep Field
ID:
ivo://CDS.VizieR/J/ApJ/606/664
Title:
MAMBO sources near NTT Deep Field
Short Name:
J/ApJ/606/664
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss identifications for 18 sources from our Max-Planck- Millimeter-Bolometer (MAMBO) 1.2mm survey of the region surrounding the NTT Deep Field. We have obtained accurate positions from Very Large Array 1.4GHz interferometry, and in a few cases IRAM millimeter interferometry, and have also made deep BVRIzJK imaging at ESO.
927. M8 and Her 36 C_2_H and c-C_3_H_2_ data
ID:
ivo://CDS.VizieR/J/A+A/626/A28
Title:
M8 and Her 36 C_2_H and c-C_3_H_2_ data
Short Name:
J/A+A/626/A28
Date:
21 Oct 2021
Publisher:
CDS
Description:
Hydrocarbons are ubiquitous in the interstellar medium, but their formation is still not well understood, depending on the physical environment they are found in. Messier 8 (M8) is host to one of the brightest Hii regions and photodissociation regions (PDRs) in our galaxy. With the observed C_2_H and c-C_3_H_2_ data toward M8, we aim at obtaining their densities and abundances and to shed some light on their formation mechanism. Using the Atacama Pathfinder Experiment (APEX) 12m, and the Institut de Radioastronomie Millimetrique (IRAM) 30m telescopes, we performed a line survey toward Herschel 36 (Her 36), which is the main ionizing stellar system in M8, and an imaging survey within 1.3x1.3pc around Her 36 of various transitions of C_2_H and C_3_H_2_. We used both Local Thermodynamic Equilibrium (LTE) and non-LTE methods to determine the physical conditions of the emitting gas along with the column densities and abundances of the observed species, which we compared with (updated) gas phase photochemical PDR models. In order to examine the role of polycyclic aromatic hydrocarbons (PAHs) in the formation of small hydrocarbons and to investigate their association with the Hii region, the PDR and the molecular cloud, we compared archival Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) 8{mu}m and the Spectral and Photometric Imaging Receiver (SPIRE) 250{mu}m continuum images with the C_2_H emission maps. We observed a total of three rotational transitions of C_2_H with their hyperfine structure components and four rotational transitions of C_3_H_2_ with ortho and para symmetries toward the HII region and the PDR of M8. Fragmentation of PAHs seems less likely to contribute to the formation of small hydrocarbons as the 8 m emission does not follow the distribution of C_2_H emission, which is more associated with the molecular cloud toward the north-west of Her 36. From the quantitative analysis, we obtained abundances of 10^-8 ^and 10^-9^ for C_2_H and c-C_3_H_2_ respectively, and volume densities of the hydrocarbon emitting gas in the range n(H_2_)~5x10^4^-5x10^6^cm^-3^. The observed column densities of C_2_H and c-C_3_H_2_ are reproduced reasonably well by our PDR models. This supports the idea that in high-UV flux PDRs, gas phase chemistry is sufficient to explain hydrocarbon abundances.
928. Maps of the 36 GHz methanol emission
ID:
ivo://CDS.VizieR/J/A+A/314/615
Title:
Maps of the 36 GHz methanol emission
Short Name:
J/A+A/314/615
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used the Effelsberg 100-meter telescope to map the 36GHz 4_-1_->3_0_E methanol transition in galactic star forming regions where methanol masers were previously detected. In most sources, the emission consists in one or several narrow (maser) features superimposed on a broader, presumably quasi-thermal component. The line shapes and positions of the narrow features are often similar to those observed in the other ClassI methanol maser transitions (at 25, 44, 84 and 95GHz), but with some exceptions. Our observations confirm that, unlike the strong ClassII methanol masers (at 12.2, and 6.6GHz), the ClassI methanol masers are offset from the compact HII regions, infrared sources and OH/H_2_O masers. In outflow sources, these are located at the edge of the molecular lobes.
929. M82-A radio continuum and polarisation study I.
ID:
ivo://CDS.VizieR/J/A+A/555/A23
Title:
M82-A radio continuum and polarisation study I.
Short Name:
J/A+A/555/A23
Date:
21 Oct 2021
Publisher:
CDS
Description:
In order to study the cosmic ray propagation and determine the magnetic field strength and dominant loss processes in the nearby prototypical starbursting galaxy M82, a multi-frequency analysis at four radio wavelengths is presented. Archival data from the Westerbork Synthesis Radio Telescope (WSRT) was reduced and a new calibration technique introduced to reach the high dynamic ranges needed for the complex source morphology. These data were combined with archival Very Large Array (VLA) data, yielding total power maps at {lambda}3cm, {lambda}6cm, {lambda}22cm, and {lambda}92cm. The data show a confinement of the emission at wavelengths of {lambda}3/{lambda}6cm to the core region and a largely extended halo reaching up to 4kpc away from the galaxy midplane at wavelengths of {lambda}22/{lambda}92cm up to a sensitivity limit of 90uJy and 1.8mJy respectively indicating different physical processes in the core and halo regions. The results are used to calculate the magnetic field strength to 98uG in the core region and to 24uG in the halo regions. From the observation of ionisation losses, the filling factor of the ionised medium could be estimated to 2%. This leads to a revised view of the magnetic field distribution in the core region and the propagation processes from the core into the halo regions.
930. Maser and infrared studies of oxygen-rich AGB stars
ID:
ivo://CDS.VizieR/J/ApJ/794/81
Title:
Maser and infrared studies of oxygen-rich AGB stars
Short Name:
J/ApJ/794/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explored an efficient method to identify evolved stars with oxygen-rich envelopes in the late asymptotic giant branch (AGB) or post-AGB phase of stellar evolution, which include a rare class of objects - the "water fountains (WF)." Our method considers the OH and H_2_O maser spectra, the near-infrared Q-parameters (these are color indices accounting for the effect of extinction), and far-infrared AKARI colors. Here we first present the results of a new survey on OH and H_2_O masers. There were 108 color-selected objects: 53 of them were observed in the three OH maser lines (1612, 1665, and 1667 MHz), with 24 detections (16 new for 1612 MHz); and 106 of them were observed in the H_2_O maser line (22 GHz), with 24 detections (12 new). We identify a new potential WF source, IRAS 19356+0754, with large velocity coverages of both OH and H_2_O maser emission. In addition, several objects with high-velocity OH maser emission are reported for the first time. The Q-parameters as well as the infrared [09]-[18] and [18]-[65] AKARI colors of the surveyed objects are then calculated. We suggest that these infrared properties are effective in isolating aspherical from spherical objects, but the morphology may not necessarily be related to the evolutionary status. Nonetheless, by considering altogether the maser and infrared properties, the efficiency of identifying oxygen-rich late/post-AGB stars could be improved.