- ID:
- ivo://CDS.VizieR/VIII/96
- Title:
- 6-GHz methanol multibeam maser catalogue
- Short Name:
- VIII/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a seven-beam receiver on the Parkes telescope, refered to as MX observations. Paper I provides sensitive unbiased coverage of a large region around the Galactic Centre. Details are given for 183 methanol maser sites in the longitude range 345{deg} through the Galactic Centre to 6{deg}. Within 6{deg} of the Galactic Centre, we found 88 maser sites, of which more than half (48) are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative of many sources at the Galactic Centre distance and beyond, and confined to a thin disc population; there is no high-latitude population that might be ascribed to the Galactic bulge. Paper II spans the longitude range 6{deg} to 20{deg}. We report the detection of 119 maser sources, of which 42 are new discoveries. Paper III covers the longitude range 330{deg}-345{deg}, yielding 198 masers, of which more than 40 per cent are new discoveries. Paper IV span the longitude range 186{deg}-330{deg}. We report 207 maser detections, 89 new to the survey. This completes the southern sky part of the methanol multibeam survey and includes a large proportion of new sources, 43 per cent. We also include results from blind observations of the Orion-Monoceros star-forming region, formally outside the latitude range of the methanol multibeam survey; only the four previously known methanol emitting sites were detected, of which we present new positions and spectra for masers at Orion A (south) and Orion B, obtained with the Multi-Element Radio Linked Interferometer Network (MERLIN) array.
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- ID:
- ivo://CDS.VizieR/J/A+A/413/233
- Title:
- 12.2 GHz methanol survey
- Short Name:
- J/A+A/413/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of 12.2GHz methanol maser survey done with the Torun 32 meter radio telescope. We examined 261 star forming sites, known as containing 6.7GHz maser emission sources. The survey resulted in 49 sources with maser line detection, with 21 previously unknown emissions. All detected 12.2GHz masers have been observed at 6.7GHz transition. Only one 12.2GHz source has no 6.7GHz counterpart. We compared basic spectral line properties at both transitions. In a few cases we observed absorption features and emitting counterparts in the other monitored frequency, at the same velocity.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3718
- Title:
- 15GHz monitoring of AGN jets with VLBA
- Short Name:
- J/AJ/137/3718
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present images from a long-term program (MOJAVE: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments) to survey the structure and evolution of parsec-scale jet phenomena associated with bright radio-loud active galaxies in the northern sky. The observations consist of 2424 15GHz Very Long Baseline Array (VLBA) images of a complete flux-density-limited sample of 135 AGNs above declination -20{deg}, spanning the period 1994 August to 2007 September. These data were acquired as part of the MOJAVE and 2cm Survey programs, and from the VLBA archive. The sample-selection criteria are based on multi-epoch parsec-scale (VLBA) flux density, and heavily favor highly variable and compact blazars. The sample includes nearly all the most prominent blazars in the northern sky, and is well suited for statistical analysis and comparison with studies at other wavelengths. Our multi-epoch and stacked-epoch images show 94% of the sample to have apparent one-sided jet morphologies, most likely due to the effects of relativistic beaming. Of the remaining sources, five have two-sided parsec-scale jets, and three are effectively unresolved by the VLBA at 15GHz, with essentially all of the flux density contained within a few tenths of a milliarcsecond.
- ID:
- ivo://CDS.VizieR/VIII/65
- Title:
- 1.4GHz NRAO VLA Sky Survey (NVSS)
- Short Name:
- VIII/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The NRAO VLA Sky Survey (NVSS) is a radio continuum survey covering the sky north of -40{deg} declination at 1.4GHz. The principal data products of the NVSS are a set of 2326 4x4{deg} continuum "cubes" with three planes containing Stokes I, Q, and U images, plus a catalog of almost 2 million discrete sources stronger than a flux density of about 2.5mJy. The images all have 45 arcsecond FWHM angular resolution and nearly uniform sensitivity. Their rms brightness fluctuations are approximately 0.45mJy/beam=0.14K (Stokes I) and 0.29mJy/beam=0.09K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from <= ~1arcsecond for the 400,000 sources stronger than 15mJy to 7arcseconds at the survey limit. A more detailed description is provided in the printed paper and at the NVSS website at http://www.cv.nrao.edu/nvss/ where all data products, user software, and updates were released as soon as they were produced and verified.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A75
- Title:
- 43GHz observation of the blazar Mrk 421
- Short Name:
- J/A+A/559/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results obtained for the AGN Markarian 421 by model-fitting the data in the visibility plane, studing the proper motion of jet components, the light curve, and the spectral index of the jet features. We compare the radio data with optical light curves obtained at the Steward Observatory, considering also the optical polarization information. Mrk 421 has a bright nucleus and a one-sided jet extending towards the north-west for a few parsecs. The model-fits show that brightness distribution is well described using 6-7 circular Gaussian components, four of which are reliably identified at all epochs; all components are effectively stationary except for component D, at ~0.4mas from the core, whose motion is however subluminal. The analysis of the light curve shows two different states, with the source being brighter and more variable in the first half of 2011 than in the second half. The highest flux density is reached in February. A comparison with the optical data reveals an increase of the V magnitude and of the fractional polarization simultaneous with the enhancement of the radio activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/655/958
- Title:
- 90-GHz observations in NGC 1333
- Short Name:
- J/ApJ/655/958
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the clustered star forming complex NGC 1333 with the BIMA and FCRAO telescopes in the transitions HCO+(1-0) and N_2_H+(1-0) over an area with resolution ~10" (0.015pc). The N_2_H+ emission follows very closely the submillimeter dust continuum emission, while HCO+ emission appears more spatially extended and also traces outflows. We have identified 93 N_2_H+ cores using the CLUMPFIND algorithm, and we derive N_2_H+ core masses between 0.05 and 2.5M_{sun}_ , with uncertainties of a factor of a few, dominated by the adopted N_2_H+ abundance.
- ID:
- ivo://CDS.VizieR/J/ApJS/51/67
- Title:
- 5 GHz Observations of Arecibo 611 MHz Sources
- Short Name:
- J/ApJS/51/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arecibo 611 MHz survey of Durdin et al. (1975) listed 3118 radio sources stronger than 0.35 Jy in the region -3d to +19d and 22h to 13h. Of these sources, 2911 have been observed using the NRAO 300 foot transit telescope at 4755 MHz. Positions, fluxes, and spectral indices are given for the 2661 detected sources. The beamwidth of the 300 foot telescope is nominally 2.8 arcmin FWHM at 6 cm, compared to the 12 arcmin beamwidth of the Arecibo survey, allowing a significant improvement in source positions.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1947
- Title:
- 37GHz observations of BL Lac objects
- Short Name:
- J/AJ/133/1947
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 37GHz data obtained at Metsahovi Radio Observatory in 2001 December-2005 April for a large sample of BL Lacertae objects. Metsahovi radio telescope is a radome enclosed antenna with a diameter of 13.7 metres. The 37 GHz receiver is a dual horn, Dicke-switched receiver with a HEMT preamplifier, and is operated at room temperature. The observations are ON-ON observations, alternating the source and the sky in each feed horn. A typical integration time to obtain one flux density data point is 1200-1600s, and the detection limit under optimal weather conditions is about 0.2Jy.
- ID:
- ivo://CDS.VizieR/J/ApJ/731/L41
- Title:
- 1.4GHz observations of bright early-type galaxies
- Short Name:
- J/ApJ/731/L41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the radio continuum emission of 396 early-type galaxies brighter than K=9, using 1.4GHz imagery from the NRAO Very Large Array Sky Survey, Green Bank 300ft Telescope, and 64m Parkes Radio Telescope. For M_K_<-24 early-type galaxies, the distribution of radio powers at fixed absolute magnitude spans four orders of magnitude and the median radio power is proportional to K-band luminosity to the power 2.78+/-0.16. The measured flux densities of M_K_<-25.5 early-type galaxies are greater than zero in all cases. It is thus highly likely that the most massive galaxies always host an active galactic nucleus or have recently undergone star formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/1961
- Title:
- 93.2GHz observations of 9C sources
- Short Name:
- J/MNRAS/430/1961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from follow-up observations of a sample of 80 radio sources, originally detected as part of the 15.2-GHz Ninth Cambridge (9C) survey. The observations were carried out, close to simultaneously, at two frequencies: 15.7GHz, using the Arcminute Microkelvin Imager (AMI) Large Array, and 93.2GHz, using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). There is currently little direct information on the 90-GHz-band source count for S<~1Jy. However, we have used the measured 15.7-to-93.2-GHz spectral-index distribution and 9C source count to predict the differential source count at 93.2GHz as 26+/-4(S/Jy)^-2.15^Jy^-1^sr^-1^; our projection is estimated to be most accurate for 10<~S<~100mJy. Our estimated differential count is more than twice the 90-GHz prediction made by Waldram et al. (2007, Cat. J/MNRAS/379/1442); we believe that this discrepancy is because the measured 43-GHz flux densities used in making their prediction were too low. Similarly, our prediction is significantly higher than that of Sadler et al. (2008, Cat. J/MNRAS/385/1656) at 95GHz. Since our spectral-index distribution is similar to the 20-to-95-GHz distribution measured by Sadler et al. and used in making their prediction, we believe that the difference is almost entirely attributable to the dissimilarity in the lower frequency counts used in making the estimates.
