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1471. RMS compact HII regions distances
ID:
ivo://CDS.VizieR/J/MNRAS/420/1656
Title:
RMS compact HII regions distances
Short Name:
J/MNRAS/420/1656
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high-resolution HI data obtained using the Australia Telescope Compact Array to resolve the near/far distance ambiguities towards a sample of compact HII regions from the Red MSX Source (RMS) survey. The high-resolution data are complemented with lower resolution archival HI data extracted from the Southern and Very Large Array (VLA) Galactic Plane surveys. We resolve the distance ambiguity for nearly all of the 105 sources where the continuum was strong enough to allow analysis of the HI absorption line structure. This represents another step in the determination of distances to the total RMS sample, which with over 1000 massive young stellar objects and compact HII regions is the largest and most complete sample of its kind. The full sample will allow the distribution of massive star formation in the Galaxy to be examined.
1472. RMS survey
ID:
ivo://CDS.VizieR/J/MNRAS/452/4029
Title:
RMS survey
Short Name:
J/MNRAS/452/4029
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of ammonia observations towards 66 massive star forming regions identified by the Red Midcourse Space Experiment Source survey. We have used the Green Bank Telescope and the K-Band Focal Plane Array to map the ammonia (NH_3_) (1,1) and (2,2) inversion emission at a resolution of 30 arcsec in 8 arcmin regions towards the positions of embedded massive star formation. We have identified a total of 115 distinct clumps, approximately two-thirds of which are associated with an embedded massive young stellar object or compact HII region, while the others are classified as quiescent. There is a strong spatial correlation between the peak NH3 emission and the presence of embedded objects. We derive the spatial distribution of the kinetic gas temperatures, line widths, and NH3 column densities from these maps, and by combining these data with dust emission maps we estimate clump masses, H_2_ column densities and ammonia abundances. The clumps have typical masses of ~1000M_{sun}_ and radii ~0.5pc, line widths of ~2km/s and kinetic temperatures of ~16-20K. We find no significant difference between the sizes and masses of the star-forming and quiescent subsamples; however, the distribution maps reveal the presence of temperature and line width gradients peaking towards the centre for the star-forming clumps while the quiescent clumps show relatively uniform temperatures and line widths throughout. Virial analysis suggests that the vast majority of clumps are gravitationally bound and are likely to be in a state of global free fall in the absence of strong magnetic fields. The similarities between the properties of the two subsamples suggest that the quiescent clumps are also likely to form massive stars in the future, and therefore provide an excellent opportunity to study the initial conditions of massive pre-stellar and protostellar clumps.
1473. RMS survey. 6cm observations of YSOs
ID:
ivo://CDS.VizieR/J/A+A/501/539
Title:
RMS survey. 6cm observations of YSOs
Short Name:
J/A+A/501/539
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 MYSO candidates located throughout the Galaxy by comparing the colours of MSX and 2MASS point sources to those of known MYSOs. The aim of these follow-up observations is to identify other objects with similar colours such as ultra compact (UC) HII regions, evolved stars and planetary nebulae (PNe) and distinguish between genuine MYSOs and nearby low-mass YSOs. To identify the populations of UCHII regions and PNe within the sample and examine their Galactic distribution. We have conducted high resolution radio continuum observations at 6cm towards 659 MYSO candidates in the northern hemisphere (10{deg}<l<250{deg}) using the Very Large Array (VLA). These observations have a spatial resolution of ~1-2" and typical image rms noise values of ~0.22mJy - sensitive enough to detect a HII region powered by B0.5 star at the far side of the Galaxy. In addition to these targeted observations we present archival data towards a further 315 RMS sources extracted from a previous VLA survey of the inner Galaxy.
1474. RMS survey: molecular observations
ID:
ivo://CDS.VizieR/J/MNRAS/437/1791
Title:
RMS survey: molecular observations
Short Name:
J/MNRAS/437/1791
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used the well-selected sample of ~1750 embedded, young, massive stars identified by the Red MSX Source (RMS) survey to investigate the Galactic distribution of recent massive star formation. We present molecular line observations for ~800 sources without existing radial velocities. We describe the various methods used to assign distances extracted from the literature and solve the distance ambiguities towards approximately 200 sources located within the solar circle using archival Hi data. These distances are used to calculate bolometric luminosities and estimate the survey completeness (~2x10^4^L_{sun}_). In total, we calculate the distance and luminosity of ~1650 sources, one third of which are above the survey's completeness threshold. Examination of the sample's longitude, latitude, radial velocities and mid-infrared images has identified ~120 small groups of sources, many of which are associated with well-known star formation complexes, such as G305, G333, W31, W43, W49 and W51. We compare the positional distribution of the sample with the expected locations of the spiral arms, assuming a model of the Galaxy consisting of four gaseous arms. The distribution of young massive stars in the Milky Way is spatially correlated with the spiral arms, with strong peaks in the source position and luminosity distributions at the arms' Galactocentric radii. The overall source and luminosity surface densities are both well correlated with the surface density of the molecular gas, which suggests that the massive star formation rate per unit molecular mass is approximately constant across the Galaxy. A comparison of the distribution of molecular gas and the young massive stars to that in other nearby spiral galaxies shows similar radial dependences. We estimate the total luminosity of the embedded massive star population to be ~0.76x10^8^L_{sun}_, 30 per cent of which is associated with the 10 most active star-forming complexes. We measure the scaleheight as a function of the Galactocentric distance and find that it increases only modestly from ~20-30pc between 4 and 8kpc, but much more rapidly at larger distances.
1475. RM Synthesis of 33 sources around M31
ID:
ivo://CDS.VizieR/J/A+A/559/A27
Title:
RM Synthesis of 33 sources around M31
Short Name:
J/A+A/559/A27
Date:
21 Oct 2021
Publisher:
CDS
Description:
Low-frequency radio continuum observations are best suited to search for radio halos of inclined galaxies. Polarization measurements at low frequencies allow the detection of small Faraday rotation measures caused by regular magnetic fields in galaxies and in the foreground of the Milky Way. The detection of low-frequency polarized emission from a spiral galaxy such as M31 allows us to assess the degree of Faraday depolarization, which can be compared with models of the magnetized interstellar medium.
1476. ROGUE. I. SDSS galaxies with FIRST
ID:
ivo://CDS.VizieR/J/ApJS/247/53
Title:
ROGUE. I. SDSS galaxies with FIRST
Short Name:
J/ApJS/247/53
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the catalog of Radio sources associated with Optical Galaxies and having Unresolved or Extended morphologies I (ROGUE I), consisting of 32616 spectroscopically selected galaxies. It is the largest handmade catalog of this kind, obtained by cross-matching galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 and radio sources from both the First Images of Radio Sky at Twenty Centimetre (FIRST) survey and the NRAO Very Large Array Sky Survey, without imposing a limit on the radio flux densities. The catalog provides a visual classification of radio and optical morphologies of galaxies presenting a FIRST core within 3" of the optical position. The radio morphological classification is performed by examining the radio-optical overlays of linear sizes equal to 1Mpc at the source distance, while the 120" image snapshots from the SDSS database are used for optical classification. The results of our search are as follows: (i) single-component unresolved and elongated radio sources constitute the major group in the ROGUE I catalog (~90%), and ~8% exhibit extended morphologies; (ii) samples of 269, 730, and 115 Fanaroff-Riley (FR) type I, II, and hybrid galaxies, respectively, are presented; (iii) we report 55 newly discovered giant/possible giant, 16 double-double, 9 X-shaped, and 25 Z-shaped radio sources; (iv) on the optical front, most galaxies have elliptical morphologies (~62%) while spirals form the second major category (~17%) followed by distorted (~12%) and lenticular (~7%) morphologies; and (v) division between the FR I and the FR II sources in the radio-optical luminosity plane is blurred, in tune with recent studies.
1477. ROSAT active galaxies identifications
ID:
ivo://CDS.VizieR/J/A+AS/122/235
Title:
ROSAT active galaxies identifications
Short Name:
J/A+AS/122/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
Table 2 gives the 5 GHz high resolution radio source properties for the 1861 Rosat-GreenBank (RGB) sources for which subarcsecond positions and core radio flux densities were obtained. After submission of this paper, we discovered a possible systematic position error in a very small subset of sources. In particular, the sources RGB J0131+005, RGB J0139+178, RGB J0143+129, RGB J0157+235A, RGB J0232+202, RGB J0233+024A, RGB J0243+171, RGB J0256+035, RGB J0303+059, RGB J0308+104, RGB J0312+243A, RGB J0312+242C, and RGB J0314+063 were all observed in our "c" epoch VLA runs and show large systematic offsets with respect to sources found in the NVSS survey. We re-examined these sources and found the position reported in the tables is accurate given our data, but that the noise on these fields before any CLEANing is abnormally high. We thank Dr. Alastair Edge for pointing out this discrepancy. Table 3 gives the 5 GHz radio source properties for the 436 Rosat-Green Bank (RGB) sources for which only low resolution data were obtained. Table 4 gives the 83 Rosat-Green Bank (RGB) sources for which no radio source greater than 5 sigma was observed in the follow-up VLA observations. These catalogs consist of radio- and X-ray-loud AGN selected from a correlation of the 1987 Green Bank radio catalog and the Rosat All-Sky Survey.
1478. ROSAT AGN content
ID:
ivo://CDS.VizieR/J/A+AS/109/147
Title:
ROSAT AGN content
Short Name:
J/A+AS/109/147
Date:
21 Oct 2021
Publisher:
CDS
Description:
The cross-correlation of the source list from the ROSAT All-Sky Survey with the 5 GHz Green Bank survey yields a list of 2127 objects. About two thirds of them are optically unidentified. The majority of the objects with known optical counterparts are quasars and radio galaxies, most of them detected in X-rays for the first time. In this paper we present a list of the previously optically identified objects with their main characteristics and discuss their general (bulk) properties. We find strong correlations between luminosities in the radio, optical, and X-ray bands which differ for quasars and radio galaxies.
1479. ROSAT-FIRST AGN correlation
ID:
ivo://CDS.VizieR/J/A+A/356/445
Title:
ROSAT-FIRST AGN correlation
Short Name:
J/A+A/356/445
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a correlation of the ROSAT All-Sky Survey with the April 1997 release of the VLA 20cm FIRST (Cat. <VIII/59>) catalogue. We focus our analysis on the 843 X-ray sources which have unique radio counterparts. The majority of these objects (84%) have optical counterparts on the POSS 1 plates. Approximately 30% have been previously classified and we obtain new spectroscopic classifications for 85 sources by comparison with the ongoing FIRST Bright Quasar Survey and 106 additional sources from our own new spectroscopic data. Approximately 51% of the sources are presently classified, and the majority of the unclassified objects are optically faint. The newly classified sources are generally radio weak, exhibiting properties intermediate with previous samples of radio- and X-ray-selected AGN. This also holds for the subsample of 71 BL Lacs which includes many intermediate objects. The 146 quasars show no evidence for a bimodal distribution in their radio-loudness parameter, indicating that the supposed division between radio-quiet and radio-loud AGN may not be real. The X-ray and radio luminosities are correlated over two decades in radio luminosity, spanning the radio-loud and radio-quiet regimes, with radio-quiet quasars showing a linear correlation between the two luminosities. Many of the sources show peculiar or unusual properties which call for more detailed follow-up observations. We also give the X-ray and radio data for the 518 X-ray sources for which more than one radio object is found. Because of the difficulties inherent in identifying optical counterparts to these complex sources, we do not consider these data in the current analysis.
1480. ROSAT Galactic Plane Survey observations
ID:
ivo://CDS.VizieR/J/A+AS/122/201
Title:
ROSAT Galactic Plane Survey observations
Short Name:
J/A+AS/122/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
The analysis of the part of the ROSAT all-sky survey covering the galactic plane is the scope of a dedicated project called the ROSAT Galactic Plane Survey. In order to statistically understand the nature of the =~14000 sources discovered by ROSAT at |b|<=20{deg}, a number of sample areas have been chosen for follow-up optical identification. In this paper we present the X-ray and optical material gathered in a region located in the Cygnus constellation, centered at l=90{deg}, b=0{deg} and covering an area of 64.5deg^2^. A total of 95 and 128 sources are detected with a maximum likelihood larger than 10 and 8 respectively. With a typical survey exposure time of the order of 700 to 900 s the flux completeness level is =~0.02cts/s corresponding to =~2x10^-13^erg/cm^2^/s. The position of the sample area allows to investigate the soft X-ray content of a rather typical region of the galactic plane. In this paper we describe the details of the observational procedures and data reduction. For each ROSAT source we list the main X-ray characteristics together with those of the proposed optical identification. When appropriate, we also show optical spectra and finding charts. The full analysis and discussion of these data are presented in a companion paper (Motch et al. 1997, Cat. <J/A+A/318/111>).