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- ID:
- ivo://CDS.VizieR/J/ApJ/590/109
- Title:
- Gamma-ray blazar in northern sky
- Short Name:
- J/ApJ/590/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using survey data, we have re-evaluated the correlation of flat-spectrum radio sources with EGRET sources in the northern sky. An analysis incorporating the radio and X-ray properties and the gamma-ray source localization is used to gauge the reliability of associations and to search for counterparts of previously unidentified EGRET sources. Above |b|=10{deg}, where the classification is complete, we find that 70% of the northern EGRET sources have counterparts similar to the bright EGRET blazars. For several of these we identify known blazar counterparts more likely than the earlier proposed 3EG association; for ~20 we have new identifications. Spectroscopic confirmation of these candidates is in progress, and we have found flat-spectrum radio quasars and BL Lacertae counterparts with redshifts as high as 4. We also find strong evidence for a set of 28 objects with no plausible counterpart like the known EGRET blazars. These thus represent either a new extragalactic population or a population of Galactic objects with a large scale height. The survey has been extended into the plane, where we find several new blazar candidates; the bulk of the sources are, however, Galactic. Looking ahead to the GLAST era, we predict that several of the present 3EG sources are composite and that higher resolution data will break these into multiple blazar identifications.
- ID:
- ivo://CDS.VizieR/J/A+A/612/A36
- Title:
- G346.056-0.021 and G346.077-0.056 radio images
- Short Name:
- J/A+A/612/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of two southern Galactic H II regions G346.056-0.021 and G346.077-0.056 which are located at a distance of 10.9kpc. The distribution of ionized gas, cold and warm dust, and the stellar population associated with the two H II regions are studied in detail using measurements at near-infrared, mid-infrared, far-infrared, submillimeter and radio wavelengths. The radio continuum maps at 1280 and 610MHz were obtained using the Giant Metrewave Radio Telescope to probe the ionized gas. The dust temperature, column density, and dust emissivity maps were generated using modified blackbody fits in the far-infrared wavelength range 160-500um. Various near- and mid-infrared color and magnitude criteria were adopted to identify candidate ionizing star(s) and the population of young stellar objects in the associated field. The radio maps reveal the presence of diffuse ionized emission displaying distinct cometary morphologies. The 1280MHz flux densities translate to ZAMS spectral types in the range O7.5V-O7V and O8.5V-O8V for the ionizing stars of G346.056-0.021 and G346.077-0.056, respectively. A few promising candidate ionizing star(s) are identified using near-infrared photometric data. The column density map shows the presence of a large, dense dust clump enveloping G346.077-0.056. The dust temperature map shows peaks towards the two HII regions. The submillimeter image shows the presence of two additional clumps, one being associated with G346.056-0.021. The masses of the clumps are estimated to range between ~1400 and 15250M_{sun}_. Based on simple analytic calculations and the correlation seen between the ionized gas distribution and the local density structure, the observed cometary morphology in the radio maps is better explained invoking the champagne-flow model.
- ID:
- ivo://CDS.VizieR/VIII/14
- Title:
- 87GB Catalog of radio sources
- Short Name:
- VIII/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- of paper: The 91m telescope in Green Blank was used during 1987 October to map 6.0sr of the sky in the [0,+75]degrees declination band at 4.85GHz. We present the 87GB catalog of 54579 discrete sources with angular sizes less than about 10.5arcmin and stronger than S about 25mJy derived from these maps. The catalog positions and flux densities have been corrected for known map biases. Their estimated rms uncertainties were verified by comparison with more accurate positions and flux densities available for some sources. The 4.85GHz normalized source counts S^5/2^.n(S) between 25mJy and 10Jy were obtained and agree well with evolutionary models based on independent data.
- 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.
- 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.
