- ID:
- ivo://CDS.VizieR/J/MNRAS/285/898
- Title:
- A3556 radio properties
- Short Name:
- J/MNRAS/285/898
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged the portion of the Shapley Concentration core surrounding the cluster A3556 at wavelengths of 36cm with the Molonglo Observatory Synthesis Telescope (MOST), and at 22 and 13cm with the Australia Telescope Compact Array (ATCA). We have defined a radio sample of 112 radio sources at 22cm. Cross-correlation with optical catalogues allowed the identification of 29 radio sources, nine of which belong to A3556. The radio and optical properties of A3556 have been studied in detail. Two extended radio sources are associated with cluster members, i.e. a narrow-angle-tail source located at a projected distance of 0.06R_A_ from the centre, possibly in the late stages of its existence, and a wide-angle-tail source at the periphery of the cluster. We also performed a statistical analysis of the cluster properties. The optical luminosity function shows that the cluster has an excess of bright optical galaxies. In agreement with well-established results, we found that the probability of radio emission increases for brighter galaxies. Furthermore, our radio luminosity function and those obtained for elliptical galaxies located in different environments (poor groups and rich clusters) are very similar, implying that the peculiar dynamical state of A3556 has no influence on the radio emission properties of the cluster galaxies.
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- ID:
- ivo://CDS.VizieR/J/A+A/368/845
- Title:
- Arcetri Catalog of H2O maser sources. Update.
- Short Name:
- J/A+A/368/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a second update of the Arcetri Catalog of water masers (Comoretto et al., 1990A&AS...84..179C; Brand et al., 1994, Cat. <J/A+AS/103/541>). The present study reports the results of the observations carried out with the Medicina 32-m radiotelescope from January 1993 to April 2000 on a sample of 300 sources. This compilation consists of newly discovered maser sources that did not appear in the previous Arcetri Catalogs and is made of: a) detections from the literature, and b) unpublished detections obtained with the Medicina antenna. Overall, 83 out of 300 sources were detected. The detection rate is low (28%) and we attribute this result to the inclusion in our survey of a rather large number of spurious maser detections that have appeared in one particular paper. The observational parameters are reported in tabular form for all the 300 sources and the spectra of the detected masers are presented. We discuss the global properties of the complete Arcetri Catalog based on Comoretto et al. (1990A&AS...84..179C), Brand et al. (1994, Cat. <J/A+AS/103/541>) and the present observations, which now contains 1013 galactic water maser sources. Of these, 937 have an IRAS counterpart within 1 arcmin from the nominal position of the maser. We establish a classification scheme based on the IRAS flux densities which allows to distinguish between water masers associated with star forming regions and late-type stars. The Arcetri Catalog represents a useful data base for systematic studies of galactic water maser sources.
- ID:
- ivo://CDS.VizieR/J/A+AS/103/541
- Title:
- Arcetri Catalogue of H2O Maser Sources
- Short Name:
- J/A+AS/103/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An update is presented of the Arcetri Atlas of water masers (Comoretto et al. 1990A&AS...84..179C). It contains the results of observations of water masers with the Medicina 32-m antenna. The observed sources were all discovered in the period 1989-1993, and were found either directly in the course of our own programs or were taken from the literature in which case they were re-observed at Medicina. We give the observed parameters of 214 sources in tabular form, and present all the spectra of the 141 detections.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A110
- Title:
- Arches cluster JVLA 6 and 10GHz images
- Short Name:
- J/A+A/647/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high angular resolution radio observations of the Arches cluster in the Galactic centre, one of the most massive young clusters in the Milky Way. The data were acquired in two epochs and at 6 and 10 GHz with the Karl G. Jansky Very Large Array (JVLA). The rms noise reached is 3-4 times better than previous observations and we have almost doubled the number of known radio stars in the cluster. Nine of them have spectral indices consistent with thermal emission from ionised stellar winds. One is a confirmed wind colliding binary and two sources are ambiguous cases. Regarding variability, the radio emission appears to be stable on time scales of a few to ten years. Finally, we have showed that the number of radio stars can be used as a tool for constraining the age or mass of a cluster and also its mass function.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/141
- Title:
- Arecibo 21cm obs. of sources in 5 GMC regions
- Short Name:
- J/ApJ/880/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report Arecibo 21cm absorption-emission observations to characterize the physical properties of neutral hydrogen (HI) in the proximity of five giant molecular clouds (GMCs): Taurus, California, Rosette, Mon OB1, and NGC 2264. Strong HI absorption was detected toward all 79 background-continuum sources in the ~60x20 square degree region. Gaussian decompositions were performed to estimate temperatures, optical depths, and column densities of the cold and warm neutral medium (CNM and WNM). The properties of individual CNM components are similar to those previously observed along random Galactic sightlines and in the vicinity of molecular clouds, suggesting a universality of cold HI properties. The CNM spin temperature (Ts) histogram peaks at ~50K. The turbulent Mach numbers of CNM components vary widely, with a typical value of ~4, indicating that their motions are supersonic. About 60% of the total HI gas is WNM, and nearly 40% of the WNM lies in thermally unstable regime 500-5000K. The observed CNM fraction is higher around GMCs than in diffuse regions, and increases with increasing column density (N_HI_) to a maximum of ~75%. On average, the optically thin approximation (N_HI_^*^) underestimates the total column density by ~21%, but we find large regional differences in the relationship between N_HI_ and the required correction factor, f=N_HI_/N_HI_^*^. We examine two different methods (linear fit of f versus log_10_(N_HI_^*^) and uniform Ts) to correct for opacity effects using emission data from the GALFA-HI survey. We prefer the uniform Ts method because the linear relationship does not produce convincing fits for all subregions.
- ID:
- ivo://CDS.VizieR/J/ApJS/130/177
- Title:
- Arecibo Dual-Beam Survey
- Short Name:
- J/ApJS/130/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arecibo Dual-Beam Survey is a "blind" 21 cm search for galaxies covering ~430deg^2^ of sky. We present the data from the detection survey as well as from the follow-up observations to confirm detections and improve positions and flux measurements. We find 265 galaxies, many of which are extremely low surface brightness. Some of these previously uncatalogued galaxies lie within the zone of avoidance, where they are obscured by the gas and dust in our Galaxy. Eighty-one of these sources are not previously catalogued optically, and there are 11 galaxies that have no associated optical counterpart or are only tentatively associated with faint wisps of nebulosity on the Digitized Sky Survey images. We discuss the properties of the survey, and in particular we make direct determinations of the completeness and reliability of the sample. The behavior of the completeness and its dependencies is essential for determining the H I mass function. We leave the discussion of the mass function for a later paper, but do note that we find many low surface brightness galaxies and seven sources with M_HI_<10^8^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/656/255
- Title:
- Arecibo methanol maser Galactic Plane Survey
- Short Name:
- J/ApJ/656/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an unbiased survey for 6.7GHz methanol masers in the Galactic plane carried out using the 305m Arecibo radio telescope. A total of 18.2deg^2^ was surveyed with uniform sampling at 35.2<=l<=53.7, |b|<=0.41. The large collecting area of Aecibo and the sensitive C-Band High receiver allowed the survey to be complete at the level of 0.27Jy, making this the most sensitive blind survey carried out to date. We detected a total of 86 sources, 48 of which are new detections. Most of the new detections have a peak flux density below 2Jy. Many methanol masers are clustered, reflecting the formation of massive stars in clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/435
- Title:
- Arecibo Methanol Maser Galactic Plane Survey. II.
- Short Name:
- J/ApJ/669/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the properties of the 6.7GHz methanol maser sample detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution of the masers in the Galaxy, and statistics of their multiwavelength counterparts is consistent with the hypothesis of 6.7GHz maser emission being associated with massive young stellar objects. Using the detection statistics of our survey, we estimate the minimum number of methanol masers in the Galaxy to be 1275.
- ID:
- ivo://CDS.VizieR/J/ApJS/93/549
- Title:
- Arecibo 1612 MHz survey supplement
- Short Name:
- J/ApJS/93/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The completeness of the Arecibo 1612 MHz survey of color-selected/IRAS sources (see references) is extended to (25-12){mu}m>-0.7. In addition (1) most IR sources with spectral types normally associated with OH/IR stars and colors outside the coverage of the original survey have been examined; (2) most ambiguous observations during the survey have been reobserved: (3) most single peaked sources have been reexamined, and 17 found with second peaks. We report 39 new 1612MHz detections, of which 34 are original. These are also surveyed in the mainlines. Analysis of the complete flux-limited survey confirms the existence of a longitude sensitivity effect in the detection of sources, which reduces the total number detected by ~4%. This analysis sets an upper limit of 16%, on the proportion of a color-selected sample that may be identified with carbon stars and/or star-formation regions.
- ID:
- ivo://CDS.VizieR/J/ApJS/121/171
- Title:
- Arecibo polarimetry of 98 pulsars
- Short Name:
- J/ApJS/121/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured full Stokes parameter profiles of 98 pulsars at 21 cm from Arecibo observatory. Average profiles are presented with integration times as long as 1/3 day. We have studied the resulting profiles and other published data on each pulsar and classified them according to the Rankin morphological scheme.
