- ID:
- ivo://CDS.VizieR/VIII/40
- Title:
- GB6 catalog of radio sources
- Short Name:
- VIII/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Green Bank 4.85GHz (lambda~6cm) survey was made with the NRAO seven-beam receiver on the (former) 91m telescope during 1986 November and 1987 October. The final set of sky maps covering the declination band 0deg<Dec.<+75deg was constructed with data from both epochs. Its noise and position errors are nearly a factor of 2^(1/2)^ smaller than in the epoch 1987 maps, from which the 87GB catalog <VIII/14> of 54,579 sources stronger than S~25mJy was extracted. Therefore, we used the new maps to make the GB6 catalog of 75,162 discrete sources with angular sizes phi<=10.5arcmin and flux densities S>=18mJy. This catalog is available in machine-readable versions with either B1950 or J2000 positions and as a printed book with B1950 positions. The GB6 weighted differential source counts S^(5/2)n(S) between 18 mJy and 7Jy agree well with evolutionary models based on independent data.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/177/255
- Title:
- GBT multiwavelength survey of Galactic center
- Short Name:
- J/ApJS/177/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of a radio continuum survey of the central 4{deg}x1{deg} with the 100m Green Bank Telescope (GBT) at wavelengths of 3.5, 6, 20, and 90cm. The 3.5 and 6cm surveys are the most sensitive and highest resolution single-dish surveys made of the central degrees of our Galaxy. We present catalogs of compact and extended sources in the central 4{deg} of our Galaxy, including detailed spectral index studies of all sources. The analysis covers star-forming regions such as Sgr B and Sgr C, where we find evidence of a mixture of thermal and nonthermal emission. The analysis quantifies the relative contribution of thermal and nonthermal processes to the radio continuum flux density toward the Galactic center (GC) region. In the central 4{deg}x1{deg} of the GC, the thermal and nonthermal flux fractions for all compact and diffuse sources are 28%/72% at 3.5cm and 19%/81% at 6cm. The total flux densities from these sources are 783+/-52 and 1063+/-93Jy at 3.5 and 6cm, respectively, excluding the contribution of Galactic synchrotron emission.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A121
- Title:
- G203.7+11.5 21cm and 11cm intensity maps
- Short Name:
- J/A+A/641/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In soft X-rays, the Monogem ring is an object with a diameter of 25{deg} located in the Galactic anti-centre. It is believed to be a faint, evolved, local supernova remnant. It is not seen at radio wavelengths, as other large supernova remnants are. We study a narrow about 4.5D long, faint Halpha-filament, G203.7+11.5, that is seen towards the centre of the Monogem ring. It causes depolarisation and excessive Faraday rotation of radio polarisation data. Polarisation observations at 11cm and 21cm with the Effelsberg 100-m telescope were analysed.
- ID:
- ivo://CDS.VizieR/J/A+A/432/737
- Title:
- General Catalogue of 6.7GHz Methanol Masers
- Short Name:
- J/A+A/432/737
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Methanol masers are often detected in regions of intense star formation. Several studies in the last decade indicate that they may even be the earliest signpost of a high-mass star-forming region. Their powerful emission makes them very good candidates for observations using both single-dish telescopes and interferometers, the latter allows detailed structural and dynamical study of these objects. We present here a catalogue of all known 6.7GHz methanol masers, discovered both by surveys that targeted possible associated objects and unbiased surveys covering a large fraction of galactic longitudes across the Galactic plane 0.5{deg}<=b<=0.5deg} for most of the regions). The 519 sources which are listed with their kinematic (galactocentric and heliocentric) distance as well as possibly associated IR objects. We find that 6.7GHz methanol masers clearly trace the molecular ring of our Galaxy, where most of the OB associations are located. The present list of masers also reports detections of other masing transitions of methanol as further information for the study of the maser phenomenon. In a further publication we will address some statistical considerations.
- ID:
- ivo://CDS.VizieR/J/AZh/88/954
- Title:
- Geometry of radio pulsar magnetospheres
- Short Name:
- J/AZh/88/954
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data on the profiles and polarization of the 10- and 20-cm emission of radio pulsars are used to calculate the angle {beta} between the rotational axis of the neutron star and its magnetic moment. It is shown that, for these calculations, it is sufficient to use catalog values of the pulse width at the 10% level W10, since the broadening of the observed pulses due to the transition to the full width W0 and narrowing of the pulses associated with the emission of radiation along tangents to the field lines approximately cancel each other out. The angles {beta}1 are calculated for 283 pulsars at 20cm and 132 pulsars at 10cm, assuming that the line of sight passes through the center of the emission cone.
- ID:
- ivo://CDS.VizieR/J/A+A/85/329
- Title:
- 4.85GHz extragalactic sources
- Short Name:
- J/A+A/85/329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eleven selected regions of sky have been surveyed at an observing frequency of 4.85GHz to limiting flux densities as low as 0.01Jy. The surveys provide a sample of 118 sources for source counts from a solid angle of 7.14x10^-3^sterad. The resulting counts are in excellent agreement with those from a previously surveyed region. The combined counts show a smooth convergence below a flux density of about 0.15Jy and indicate that the convergence becomes steeper below a flux density of 0.02Jy. No evidence for anisotropy is found.
- ID:
- ivo://CDS.VizieR/J/A+A/424/371
- Title:
- 1.4GHz First Look Survey (FLS)
- Short Name:
- J/A+A/424/371
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The First Look Survey (FLS) is the first scientific product to emerge from the Spitzer Space Telescope. A small region of this field (the verification strip) has been imaged very deeply, permitting the detection of cosmologically distant sources. We present Westerbork Synthesis Radio Telescope (WSRT) observations of this region, encompassing a 1 sq. deg field, centred on the verification strip (J2000 RA=17:17:00.00, DE=59:45:00.000). The radio images reach a noise level of 8.5 microJy per beam - the deepest WSRT image made to date. We summarise here the first results from the project, and present the final mosaic image, together with a list of detected sources. The effect of source confusion on the position, size and flux density of the faintest sources in the source catalogue are also addressed. The results of a serendipitous search for HI emission in the field are also presented. Using a subset of the data, we clearly detect HI emission associated with four galaxies in the central region of the FLSv. These are identified with nearby, massive galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/474/1093
- Title:
- 30GHz flux densities of CJF sources
- Short Name:
- J/A+A/474/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim was to measure the 30-GHz flux densities of the 293 sources in the Caltech-Jodrell Bank flat-spectrum (CJF) sample. The measurements are part of an ongoing programme to measure the spectral energy distributions of flat spectrum radio sources and to correlate them with the milliarcsecond structures from VLBI and other measured astrophysical properties. The 30-GHz data were obtained with a twin-beam differencing radiometer system mounted on the Torun 32-m telescope. The system has an angular resolution of 1.2arcmin. Together with radio spectral data obtained from the literature, the 30-GHz data have enabled us to identify 42 of the CJF sources as Giga-hertz Peaked Spectrum (GPS) sources. Seventeen percent of the sources have rising spectra (alpha>0) between 5 and 30GHz.
- ID:
- ivo://CDS.VizieR/J/ApJ/488/224
- Title:
- 4.85 GHz fluxes of H II regions
- Short Name:
- J/ApJ/488/224
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky flux catalog of 760 H II regions with angular sizes ranging up to 10' at 4.85GHz. The data were compiled in a self-consistent manner from existing images of the Green Bank and Parkes-MIT-NRAO 4.85GHz radio continuum surveys. Nearly 35% of these H II regions have fluxes measured from these surveys for the first time. We compared our results to the previously published source catalogs which fit the same data. The new flux measurements agree within 5%-7% of these values and fall well within the formal errors. The diameters fall within 16% of the previously published fits to the same data, within the formal uncertainties of these values.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A111
- Title:
- 22GHz image of 3C 273
- Short Name:
- J/A+A/604/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RadioAstron is a 10m orbiting radio telescope mounted on the Spektr-R satellite, launched in 2011, performing Space Very Long Baseline Interferometry (SVLBI) observations supported by a global ground array of radio telescopes. With an apogee of ~350000km, it is offering for the first time the possibility to perform as-resolution imaging in the cm-band. The RadioAstron Active Galactic Nuclei (AGN) polarization Key Science Project (KSP) aims at exploiting the unprecedented angular resolution provided by RadioAstron to study jet launching/collimation and magnetic-field configuration in AGN jets. The targets of our KSP are some of the most powerful blazars in the sky. We present observations at 22GHz of 3C 273, performed in 2014, designed to reach a maximum baseline of approximately nine Earth diameters. Reaching an angular resolution of 0.3mas, we study a particularly low-activity state of the source, and estimate the nuclear region brightness temperature, comparing with the extreme one detected one year before during the RadioAstron early science period.We also make use of the VLBA-BU-BLAZAR survey data, at 43GHz, to study the kinematics of the jet in a ~1.5-year time window. We find that the nuclear brightness temperature is two orders of magnitude lower than the exceptionally high value detected in 2013 with RadioAstron at the same frequency (1.4x10^13^K, source-frame), and even one order of magnitude lower than the equipartition value. The kinematics analysis at 43 GHz shows that a new component was ejected ~2 months after the 2013 epoch, visible also in our 22GHz map presented here. Consequently this was located upstream of the core during the brightness temperature peak. Fermi-LAT observations for the period 2010-2014 do not show any gamma-ray flare in conjunction with the passage of the new component by the core at 43GHz. These observations confirm that the previously detected extreme brightness temperature in 3C 273, exceeding the inverse Compton limit, is a short-lived phenomenon caused by a temporary departure from equipartition. Thus, the availability of interferometric baselines capable of providing as angular resolution does not systematically imply measured brightness temperatures over the known physical limits for astrophysical sources.
