Radio properties of the <i>γ</i> ‐ray emitting CSO candidate 2234+282

An, Tao; Cui, Yuzhu; Gabányi, K. É.; Frey, S.; Baan, Willem A.; Zhao, Wei

doi:10.1002/asna.201512266

Cited by 13 publications

(27 citation statements)

References 18 publications

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“…Only recently, Migliori et al (2016) reported of the first detection of an established CSO/GPS, PKS 1718-649. This result follows the discussions of a few γ-ray CSOcandidates detected by Fermi/LAT (see also D'Ammando et al 2016, for a summary): 4C+55.1 (McConville et al 2011), PKS 1413+135 (Gugliucci et al 2005), 2234+282 (An et al 2016), and PMN J1603-4904 (Müller et al 2014).…”

Section: Introductionsupporting

confidence: 87%

The MHz-peaked radio spectrum of the unusualγ-ray source PMN J1603–4904

Müller

Burd

Schulz

et al. 2016

A&A

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Context. The majority of bright extragalactic γ-ray sources are blazars. Only a few radio galaxies have been detected by Fermi/LAT. Recently, the GHz-peaked spectrum source PKS 1718-649 was confirmed to be γ-ray bright, providing further evidence for the existence of a population of γ-ray loud, compact radio galaxies. A spectral turnover in the radio spectrum in the MHz to GHz range is a characteristic feature of these objects, which are thought to be young due to their small linear sizes. The multiwavelength properties of the γ-ray source PMN J1603-4904 suggest that it is a member of this source class. Aims. The known radio spectrum of PMN J1603-4904 can be described by a power law above 1 GHz. Using observations from the Giant Metrewave Radio Telescope (GMRT) at 150, 325, and 610 MHz, we investigate the behavior of the spectrum at lower frequencies to search for a low-frequency turnover. Methods. Data from the TIFR GMRT Sky Survey (TGSS ADR) catalog and archival GMRT observations were used to construct the first MHz to GHz spectrum of PMN J1603-4904. Results. We detect a low-frequency turnover of the spectrum and measure the peak position at about 490 MHz (rest-frame), which, using the known relation of peak frequency and linear size, translates into a maximum linear source size of ∼1.4 kpc. Conclusions. The detection of the MHz peak indicates that PMN J1603-4904 is part of this population of radio galaxies with turnover frequencies in the MHz to GHz regime. Therefore it can be considered the second confirmed object of this kind detected in γ-rays. Establishing this γ-ray source class will help to investigate the γ-ray production sites and to test broadband emission models.

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Section: Introductionsupporting

confidence: 87%

The MHz-peaked radio spectrum of the unusualγ-ray source PMN J1603–4904

Müller

Burd

Schulz

et al. 2016

A&A

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“…High resolution VLBI spectral imaging observations are needed to determine the nature of those objects, which has been done in the case of 2234+282 (An et al 2016). However no convincing CSO γ-ray emitter has been found to date at redshifts beyond z>0.006.…”

Section: Empty Fieldsmentioning

confidence: 99%

Radio Follow-up on All Unassociated Gamma-Ray Sources from the ThirdFermiLarge Area Telescope Source Catalog

Schinzel

Petrov²,

Taylor

et al. 2017

ApJ

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The third Fermi Large Area Telescope (LAT) γ-ray source catalog (3FGL) contains over 1000 objects for which there is no known counterpart at other wavelengths. The physical origin of the γ-ray emission of those objects is unknown. Such objects are commonly referred to as unassociated and mostly do not exhibit significant γ-ray flux variability. We performed a survey of all unassociated γ-ray sources found in 3FGL using the Australia Telescope Compact Array and Very Large Array in the range of 4.0-10.0 GHz. We found 2097 radio candidates for association with γ-ray sources. The follow-up with very long baseline interferometry for a subset of those candidates yielded 142 new AGN associations with γ-ray sources, provided alternative associations for 7 objects, and improved positions for another 144 known associations to the milliarcsecond level of accuracy. In addition, for 245 unassociated γ-ray sources we did not find a single compact radio source above 2 mJy within 3σ of their γ-ray localization. A significant fraction of these empty fields, 39%, are located away from the galactic plane. We also found 36 extended radio sources that are candidates for association with a corresponding γ-ray object, 19 of which are most likely supernova remnants or HII regions, whereas 17 could be radio galaxies.

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“…2234 + 282 (CTD 135): An et al (2016) have claimed this BL Lac to be a compact symmetric object with a two-sided jet, based on a comparison of VLBA maps at 8.4 and 15 GHz. However, the angular resolution is insufficient to determine a spectral index for the putative core feature.…”

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confidence: 99%

MOJAVE. XIII. PARSEC-SCALE AGN JET KINEMATICS ANALYSIS BASED ON 19 YEARS OF VLBA OBSERVATIONS AT 15 GHz

et al. 2016

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We present 1625 new 15 GHz (2 cm) VLBA images of 295 jets associated with active galactic nuclei (AGNs) from the MOJAVE and 2 cm VLBA surveys, spanning observations between 1994 August 31 and 2013 August 20. For 274 AGNs with at least 5 VLBA epochs, we have analyzed the kinematics of 961 individual bright features in their parsec-scale jets. A total of 122 of these jets have not been previously analyzed by the MOJAVE program. In the case of 451 jet features that had at least 10 epochs, we also examined their kinematics for possible accelerations. At least half of the well-sampled features have non-radial and/or accelerating trajectories, indicating that non-ballistic motion is common in AGN jets. Since it is impossible to extrapolate any accelerations that occurred before our monitoring period, we could only determine reliable ejection dates for~24% of those features that had significant proper motions. The distribution of maximum apparent jet speeds in all 295 AGNs measured by our program to date is peaked below c 5 , with very few jets with apparent speeds above c 30 . The fastest speed in our survey is c 50 , measured in the jet of the quasar PKS 0805−07, and is indicative of a maximum jet Lorentz factor of ∼50 in the parent population. An envelope in the maximum jet speed versus redshift distribution of our sample provides additional evidence of this upper limit to the speeds of radio-emitting regions in parsec-scale AGN jets. The Fermi-LAT-detected gamma-ray AGNs in our sample have, on average, higher jet speeds than non-LAT-detected AGNs, indicating a strong correlation between parsec-scale jet speed and the gamma-ray Doppler boosting factor. We have identified 11 moderate-redshift ( < z 0.35) AGNs with fast apparent speeds (> c 10 ) that are strong candidates for future TeV gamma-ray detection. Of the five gamma-ray loud narrow-lined Seyfert I AGNs in our sample, three show highly superluminal jet motions, while the others have sub-luminal speeds. This indicates that some narrowlined Seyfert I AGNs possess powerful jets with Lorentz factors in excess of 10, and viewing angles less than  10 , consistent with those of typical BL Lac objects and flat-spectrum radio quasars.

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Radio properties of the γ ‐ray emitting CSO candidate 2234+282

Cited by 13 publications

References 18 publications

The MHz-peaked radio spectrum of the unusualγ-ray source PMN J1603–4904

The MHz-peaked radio spectrum of the unusualγ-ray source PMN J1603–4904

Radio Follow-up on All Unassociated Gamma-Ray Sources from the ThirdFermiLarge Area Telescope Source Catalog

MOJAVE. XIII. PARSEC-SCALE AGN JET KINEMATICS ANALYSIS BASED ON 19 YEARS OF VLBA OBSERVATIONS AT 15 GHz

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