Radio emission of the galaxy Markaryan 668 in the frequency range 2.3?14.4 GHz

AbstractLow-frequency radio emission allows powerful active galactic nuclei (AGN) to be selected in a way that is unaffected by dust obscuration and orientation of the jet axis. It also reveals past activity (e.g. radio lobes) that may not be evident at higher frequencies. Currently, there are too few “radio-loud” galaxies for robust studies in terms of redshift-evolution and/or environment. Hence our use of new observations from the Murchison Widefield Array (the SKA-Low precursor), over the southern sky, to construct the GLEAM 4-Jy Sample (1,860 sources at S151MHz > 4 Jy). This sample is dominated by AGN and is 10 times larger than the heavily relied-upon 3CRR sample (173 sources at S178MHz > 10 Jy) of the northern hemisphere. In order to understand how AGN influence their surroundings and the way galaxies evolve, we first need to correctly identify the galaxy hosting the radio emission. This has now been completed for the GLEAM 4-Jy Sample – through repeated visual inspection and extensive checks against the literature – forming a valuable, legacy dataset for investigating relativistic jets and their interplay with the environment.

Study of the Magnetic Field of the Galaxy using Correlation Functions of the Intensity of Synchrotron Background Radio Emission

Symposium - International Astronomical Union ◽

10.1017/s0074180900230441 ◽

1996 ◽

Vol 169 ◽

pp. 615-616

Author(s):

V.R. Shoutenkov

Keyword(s):

Magnetic Field ◽

Radio Emission ◽

Correlation Functions ◽

Theoretical Calculations ◽

Angular Separation ◽

Field Studies ◽

Position Angle ◽

The Galaxy ◽

Image Position ◽

The Magnetic Field

The possibility to study magnetic field of the Galaxy calculating correlation or structure functions of synchrotron background radio emission have been known long ago (Kaplan and Pikel'ner (1963); Getmantsev (1958)). But this method had not been as popular as other methods of magnetic field studies. However theoretical calculations made by Chibisov and Ptuskin (1981) showed that correlation functions of intensity of synchrotron background radio emission can give a lot of valuable information about galactic magnetic fields because of the intensity of synchrotron background radio emission depends on H⊥. According to this theory correlation C(θ, φ) and structure S(θ, φ) functions of intensity, as functions of angular separation θ between two lines of sight and position angle φ on the sky between this two lines of sight, can be presented as a sum of isotropic (not dependent from angle φ) and anisotropic parts:

Jupiter's Radiation Belts and Upper Atmosphere

Symposium - International Astronomical Union ◽

10.1017/s0074180900025626 ◽

1974 ◽

Vol 65 ◽

pp. 375-383

Author(s):

Joseph J. Degioanni ◽

John R. Dickel

Keyword(s):

Radio Emission ◽

Radiation Belts ◽

Upper Atmosphere ◽

Mixing Ratio ◽

Frequency Range ◽

Emission Data ◽

High Energies ◽

Isotropic Distribution ◽

Relativistic Particles ◽

Flat Distribution

Models of Jupiter's radiation belts have been constructed to determine the distribution of particles and their energies which will produce the observed decimetric radio emission. Data on the spectrum and the variation of emission with Jovian longitude have been used to show that the relativistic particles have a nearly isotropic distribution with high energies (of order 100 MeV) within 2 Jovian radii and a very flat distribution in the equatorial plane of low energy particles further out in the magnetosphere.Subtraction of the emission predicted by this model from the total radio emission shows that the thermal contribution in the frequency range between 3000 and 10000 MHz is somewhat less than had been previously expected. (The brightness temperature of the planetary disk is 180 K at 3000 MHz, for example.) This suggests that the ammonia mixing ratio in Jupiter's upper atmosphere may be as high as 0.002.

Radio Emission from Interstellar Hydrogen Cyanide and X-ogen

Highlights of Astronomy ◽

10.1017/s1539299600000368 ◽

1971 ◽

Vol 2 ◽

pp. 407-412

Author(s):

Lewis E. Snyder ◽

David Buhl

Keyword(s):

Radio Emission ◽

Hydrogen Cyanide ◽

Emission Spectra ◽

Interstellar Molecule ◽

Emission Signal ◽

The Galaxy

AbstractRadio emission spectra from the J = 1−0 transition of H12C14N and H13C14N, two molecular isotopes of hydrogen cyanide, have been detected at 88.6 and 86.3 GHz, respectively. In addition, an emission signal from a new and unidentified interstellar molecule was detected at 89.2 GHz. The new molecule temporarily has been named ‘X-ogen’ until its chemical identity can be determined. X-ogen has been detected in several regions and may be as common as hydrogen cyanide in the Galaxy.

SIMULATION OF RADIO SIGNALS FROM 1-10 TeV AIR SHOWERS USING EGSNRC

International Journal of Modern Physics A ◽

10.1142/s0217751x06033386 ◽

2006 ◽

Vol 21 (supp01) ◽

pp. 65-69 ◽

Cited By ~ 3

Author(s):

R. Engel ◽

N. N. Kalmykov ◽

A. A. Konstantinov

Keyword(s):

Monte Carlo ◽

Radio Emission ◽

Monte Carlo Simulations ◽

Frequency Spectrum ◽

Radial Dependence ◽

Frequency Range ◽

Air Showers ◽

Shower Development ◽

Radio Signals ◽

The Individual

Cherenkov and geosynchrotron radiation are considered as two fundamental mechanisms of the radio emission generated by extensive air showers (EAS). The code EGSnrc is used for Monte-Carlo simulations of the individual shower development. Calculations of the radial dependence and frequency spectrum of the emitted radiation are performed for the LOPES experiment frequency range.

Spectrophotometry of the galaxy Markaryan 266

Astrophysics ◽

10.1007/bf01005515 ◽

1981 ◽

Vol 16 (4) ◽

pp. 366-374 ◽

Cited By ~ 2

Author(s):

A. R. Petrosyan

Keyword(s):

The Galaxy ◽

Galaxy Markaryan

Radio Continuum Emission from the Nuclei of Normal Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600003877 ◽

1980 ◽

Vol 5 ◽

pp. 177-184 ◽

Cited By ~ 2

Author(s):

J. M. van der Hulst

Keyword(s):

Radio Emission ◽

Galactic Center ◽

Galactic Nuclei ◽

Radio Continuum ◽

Continuum Emission ◽

Thermal Source ◽

Very Large Array ◽

Normal Galaxies ◽

The Galaxy ◽

Sgr A

During the last few years detailed and sensitive observations of the radio emission from the nuclei of many normal spiral galaxies has become available. Observations from the Very Large Array (VLA) of the National Radio Astronomy Observatory (NRAO1), in particular, enable us to distinguish details on a scale of ≤100 pc for galaxies at distances less than 21 Mpc. The best studied nucleus, however, still is the center of our own Galaxy (see Oort 1977 and references therein). Its radio structure is complex. It consists of an extended non-thermal component 200 × 70 pc in size, with embedded therein several giant HII regions and the central source Sgr A (˜9 pc in size). Sgr A itself consists of a thermal source, Sgr A West, located at the center of the Galaxy, and a weaker, non-thermal source, Sgr A East. Sgr A West moreover contains a weak, extremely compact (≤10 AU) source. The radio morphology of several other galactic nuclei is quite similar to that of the Galactic Center, as will be discussed in section 2. Recent reviews of the radio properties of the nuclei of normal galaxies have been given by Ekers (1978a,b) and De Bruyn (1978). The latter author, however, concentrates on galaxies with either active nuclei or an unusual radio morphology. In this paper I will describe recent results from the Westerbork Synthesis Radio Telescope (WSRT, Hummel 1979), the NRAO 3-element interferometer (Carlson, 1977; Condon and Dressel 1978), and the VLA (Heckman et al., 1979; Van der Hulst et al., 1979). I will discuss the nuclear radio morphology in section 2, the luminosities in section 3, and the spectra in section 4. In section 5 I will briefly comment upon the possible implications for the physical processes in the nuclei that are responsible for the radio emission.

Hydrostatic equilibrium of gas, extent of cosmic ray confinement, and radio emission in the Galaxy

The Astrophysical Journal ◽

10.1086/155069 ◽

1977 ◽

Vol 212 ◽

pp. 494 ◽

Cited By ~ 37

Author(s):

G. D. Badhwar ◽

S. A. Stephens

Keyword(s):

Radio Emission ◽

Cosmic Ray ◽

Hydrostatic Equilibrium ◽

The Galaxy

Radio haloes around galaxies and in clusters

Symposium - International Astronomical Union ◽

10.1017/s0074180900144493 ◽

1978 ◽

Vol 79 ◽

pp. 161-163

Author(s):

V. L. Ginzburg

Keyword(s):

Cosmic Rays ◽

Radio Emission ◽

Cosmic Ray ◽

Relativistic Electrons ◽

Radio Halo ◽

Normal Galaxies ◽

Extended Region ◽

The Galaxy ◽

Nuclear Component ◽

Galactic Sources

The question of whether or not our and other normal galaxies have some sort of halo - an extended region containing, in particular, cosmic rays - has been discussed for no less than 25 years. Such a “cosmic ray halo” (CRH) appears as a radio-halo, although the absence of the latter is not evidence against the presence of CRH. the point is that the relativistic electrons responsible for the radio emission from the radio-halo undergo synchrotron and Compton losses which are practically absent in the case of the cosmic-ray proton-nuclear component. Possibly because the discussion concerning the existence of the radio-halo in the Galaxy has lasted for years it has acquired a particular character. the latter is clearly reflected in the report by Baldwin (1976) who emphasized that: ȜIn this discussion so far I have avoided the use of the phrase Ȝradio-haloȝ. It arouses antagonism in otherwise placid astronomers and many sought to deny its existence …ȝ Such a situation evidently reflects the difficulties that arise in detecting the radio-halo of our own Galaxy when account is taken of other confusing galactic sources as well as of the metagalactic background.

The Pitch Angles of Electrons in Jupiter’s Radiation Belt

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000014636 ◽

1976 ◽

Vol 3 (1) ◽

pp. 53-55 ◽

Cited By ~ 12

Author(s):

J. A. Roberts

Keyword(s):

Radio Emission ◽

Pitch Angle ◽

Radiation Belt ◽

Synchrotron Emission ◽

Angle Distribution ◽

Space Probe ◽

Frequency Range ◽

Pitch Angle Distribution ◽

5 Ghz ◽

Apparent Conflict

The radio emission from Jupiter in the frequency range from ∽ 50 MHz to ∽ 5 GHz is mainly synchrotron emission from electrons in the intense radiation belt which surrounds Jupiter out to several planetary radii. Information about the pitch angles of these electrons can be derived both from the radio observations and from the Pioneer space probe observations. In this communication we discuss the pitch angle distribution inferred from the radio data and the apparent conflict with the Pioneer data.