Astrometric Evidence for a Population of Dislodged AGNs

Makarov, Valeri V.; Frouard, Julien; Berghea, Ciprian T.; Rest, A.; Chambers, K.; Kaiser, N.; Kudritzki, Rolf‐Peter; Magnier, E. A.

doi:10.3847/2041-8213/835/2/l30

Cited by 46 publications

(55 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We selected all Gaia DR2 objects within 1 ′′ of each ICRF3 1 source, using the VLBI positions listed in ICRF3. The search radius corresponds to the upper limit of genuine positional differences found in the previous analysis (Makarov et al 2017). This search resulted in 3413 tentative matches, with some of the radio sources associated with more than one Gaia source.…”

Section: Radio-optical Offsetsmentioning

confidence: 99%

“…Following the method first proposed in Makarov et al (2017), we collected a large number of high-quality images of RORF objects and visually inspected all of them. Some of the radio-loud AGNs in our sample reside in the cores of luminous galaxies.…”

Section: Independent Vettingmentioning

confidence: 99%

“…The two data releases of Gaia allowed us to look at the problem through the magnifying glass of space-grade astrometry. Based on much more accurate DR1 data, concluded that 6% of sources with accurate VLBI positions have significant differences at 99% confidence level, while Makarov et al (2017) estimated that more than 4% of the smaller ICRF2 sample (Fey et al 2015) differ in their radio and optical positions by more than 12σ, after removing as many contaminants as possible.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Precious Set of Radio-optical Reference Frame Objects in the Light of Gaia DR2 Data

Макаров

Berghea

Frouard

et al. 2019

ApJ

Self Cite

View full text Add to dashboard Cite

We investigate a sample of 3413 International Celestial Reference Frame (ICRF3) extragalactic radio-loud sources with accurate positions determined by VLBI in the S/X band, mostly active galactic nuclei (AGN) and quasars, which are cross-matched with optical sources in the second Gaia data release (Gaia DR2). The main goal of this study is to determine a core sample of astrometric objects that define the mutual orientation of the two fundamental reference frames, the Gaia (optical) and the ICRF3 (radio) frames. The distribution of normalized offsets between the VLBI sources and their optical counterparts is non-Rayleigh, with a deficit around the modal value and a tail extending beyond the 3σ confidence level. A few filters are applied to the sample in order to discard double cross-matches, confusion sources, and Gaia astrometric solutions of doubtful quality. Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and Dark Energy Survey (DES) stacked multicolor images are used to further deselect objects that are less suitable for precision astrometry, such as extended galaxies, double and multiple sources, and obvious misidentifications. After this cleaning, 2643 quasars remain, of which 20% still have normalized offset magnitudes exceeding 3, or a 99% confidence level. We publish a list of 2119 radio-loud quasars of prime astrometric quality. The observed dependence of binned median offset on redshift shows the expected decline at small redshifts, but also an unexpected rise at z ∼ 1.6, which may be attributed to the emergence of the C IV emission line in the Gaia's G band. The Gaia DR2 parallax zeropoint is found to be color-dependent, suggesting an uncorrected instrumental calibration effect.

show abstract

Section: Radio-optical Offsetsmentioning

confidence: 99%

Section: Independent Vettingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Precious Set of Radio-optical Reference Frame Objects in the Light of Gaia DR2 Data

Макаров

Berghea

Frouard

et al. 2019

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…But some objects may require further checks. In particular, Makarov et al (2017) publish a list of 188 objects (out of 2,293 ICRF2 sources), most of them with z < 0.5, with offsets up to 1 arcsec, the latter corresponds to a distance of ∼7.5 kpc at z ∼0.5. They propose that 89 of them may be AGNs (quasars and BL Lac) dislodged from their host galaxies' centers.…”

Section: Quasars In Gaia's First Data Releasementioning

confidence: 99%

Gaia Space Mission and Quasars

Zwitter

2017

Front. Astron. Space Sci.

View full text Add to dashboard Cite

“…Recent comparisons of VLBI positions of extragalactic radio-loud sources with their optical counterparts from the first Gaia release shows that the radio and optical emission regions are physically offset for a fraction of luminous AGN (Mignard et al 2016;Kovalev et al 2017;Makarov et al 2017;Petrov & Kovalev 2017a,b). The presence of ∼ 10 mas offsets in the radiooptical positions of reference AGN was previously investigated by Orosz & Frey (2013); Zacharias & Zacharias (2014).…”

Section: Introductionmentioning

confidence: 99%

Galaxies as High-resolution Telescopes

Barnacka

2017

ApJ

View full text Add to dashboard Cite

Recent observations show a population of active galaxies with milliarcseconds offsets between optical and radio emission. Such offsets can be an indication of extreme phenomena associated with supermassive black holes including relativistic jets, binary supermassive black holes, or even recoiling supermassive black holes. However, the multi-wavelength structure of active galaxies at a few milliarcseconds cannot be resolved with direct observations. We propose using strong gravitational lensing to elucidate the multi-wavelength structure of sources. When sources are located close to the caustic of lensing galaxy, even small offset in the position of the sources results in a drastic difference in the position and magnification of mirage images. We show that the angular offset in the position of the sources can be amplified more than 50 times in the observed position of mirage images. We find that at least 8% of the observed gravitationally lensed quasars will be in the caustic configuration. The synergy between SKA and Euclid will provide an ideal set of observations for thousands of gravitationally lensed sources in the caustic configuration, which will allow us to resolve the multiwavelength structure for a large ensemble of sources, and study the physical origin of radio emissions, their connection to supermassive black holes, and their cosmic evolution.

show abstract

Astrometric Evidence for a Population of Dislodged AGNs

Cited by 46 publications

References 23 publications

The Precious Set of Radio-optical Reference Frame Objects in the Light of Gaia DR2 Data

The Precious Set of Radio-optical Reference Frame Objects in the Light of Gaia DR2 Data

Gaia Space Mission and Quasars

Galaxies as High-resolution Telescopes

Contact Info

Product

Resources

About