Discovery of 24 radio-bright quasars at 4.9 ≤ <i>z</i> ≤ 6.6 using low-frequency radio observations

Gloudemans, A. J.; Duncan, K. J.; Saxena, A.; Harikane, Yuichi; Hill, Gary J.; Zeimann, Greg; Röttgering, H. J. A.; Yang, Da-Ming; Bañados, Eduardo; Drabent, A.; Hardcastle, M. J.; Lansbury, G. B.; Magliocchetti, M.; Miley, G. K.; Nanni, Riccardo; Shimwell, T. W.; Smith, Daniel; Venemans, Bram; Wagenveld, J.

doi:10.1051/0004-6361/202244763

Cited by 18 publications

(13 citation statements)

References 147 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This detection was expected as a FIRST counterpart was required for its selection (see Section 3.3). In the LoTSS-DR2 catalog, there are two matches: P173+48 and P207+37 (these two quasars were also recently reported by Gloudemans et al 2022). In the RACS catalog, there are also two matches: P050-18 and P193-02.…”

Section: New Radio-loud Quasarssupporting

confidence: 64%

“…The discovery of the 55 quasars presented in this work has been a large effort, involving multiple observatories in the time frame 2013 November 19-2022 September 28. Five of these quasars have been independently discovered by other groups: P158-14 by Chehade et al (2018), P173+48 and P207+37 by Gloudemans et al (2022), and P127+26 by S. Warren et al 2023, in preparation. A few of these quasars have been part of multiple follow-up campaigns, and some of their properties have been presented in the literature (e.g., Decarli et al 2018;Eilers et al 2020;Venemans et al 2020;Bischetti et al 2022).…”

Section: Spectroscopic Observationsmentioning

confidence: 94%

See 1 more Smart Citation

The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5

Bañados

Schindler

Venemans

et al. 2023

ApJS

View full text Add to dashboard Cite

The identification of bright quasars at z ≳ 6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang. We present the spectroscopic confirmation of 55 quasars at redshifts 5.6 < z < 6.5 and UV magnitudes −24.5 < M 1450 < −28.5 identified in the optical Pan-STARRS1 and near-IR VIKING surveys (48 and 7, respectively). Five of these quasars have independently been discovered in other studies. The quasar sample shows an extensive range of physical properties, including 17 objects with weak emission lines, 10 broad absorption line quasars, and 5 objects with strong radio emission (radio-loud quasars). There are also a few notable sources in the sample, including a blazar candidate at z = 6.23, a likely gravitationally lensed quasar at z = 6.41, and a z = 5.84 quasar in the outskirts of the nearby (D ∼ 3 Mpc) spiral galaxy M81. The blazar candidate remains undetected in NOEMA observations of the [C ii] and underlying emission, implying a star formation rate <30–70 M ⊙ yr−1. A significant fraction of the quasars presented here lies at the foundation of the first measurement of the z ∼ 6 quasar luminosity function from Pan-STARRS1 (introduced in a companion paper). These quasars will enable further studies of the high-redshift quasar population with current and future facilities.

show abstract

Section: New Radio-loud Quasarssupporting

confidence: 64%

Section: Spectroscopic Observationsmentioning

confidence: 94%

The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5

Bañados

Schindler

Venemans

et al. 2023

ApJS

View full text Add to dashboard Cite

show abstract

“…In addition, we study radio detections among these new quasars by crossmatching (2″) new quasars with the catalogs from the Faint Images of the Radio Sky at Twenty centimeters (FIRST; Becker et al 1995), the first epoch of the Very Large Array Sky Survey (VLASS; Gordon et al 2020;Lacy et al 2020), and the second data release from the ongoing LOw-Frequency ARray (LOFAR) Two-meter Sky Survey (LoTSS; Shimwell et al 2022). The crossmatch radius is chosen following recent LOFAR studies (e.g., Retana-Montenegro & Röttgering 2018; Gloudemans et al 2022), although it might be small for matching the FIRST catalog. As a first test, we choose this radius for a reliable detection.…”

Section: Examples Of Scientific Analysismentioning

confidence: 99%

DESI z ≳ 5 Quasar Survey. I. A First Sample of 400 New Quasars at z ∼ 4.7–6.6

Yang,

Fan,

Gupta

et al. 2023

ApJS

View full text Add to dashboard Cite

We report the first results of a high-redshift (z ≳ 5) quasar survey using the Dark Energy Spectroscopic Instrument (DESI). As a DESI secondary target program, this survey is designed to carry out a systematic search and investigation of quasars at 4.8 < z < 6.8. The target selection is based on the DESI Legacy Imaging Surveys (the Legacy Surveys) DR9 photometry, combined with the Pan-STARRS1 data and J-band photometry from public surveys. A first quasar sample has been constructed from the DESI Survey Validation 3 (SV3) and first-year observations until 2022 May. This sample includes more than 400 new quasars at redshift 4.7 ≤ z < 6.6, down to 21.5 magnitude (AB) in the z band, discovered from 35% of the entire target sample. Remarkably, there are 220 new quasars identified at z ≥ 5, more than one-third of existing quasars previously published at this redshift. The observations so far result in an average success rate of 23% at z > 4.7. The current spectral data set has already allowed analysis of interesting individual objects (e.g., quasars with damped Lyα absorbers and broad absorption line features), and statistical analysis will follow the survey’s completion. A set of science projects will be carried out leveraging this program, including quasar luminosity function, quasar clustering, intergalactic medium, quasar spectral properties, intervening absorbers, and properties of early supermassive black holes. Additionally, a sample of 38 new quasars at z ∼ 3.8–5.7 discovered from a pilot survey in the DESI SV1 is also published in this paper.

show abstract

“…Redshifts >5 are not reliable either in the SDSS quasar catalogue or in the photometric redshift estimates. We have therefore removed all redshifts z > 5 from either of these two sources from the final catalogue but have merged in the DR2 high-z quasar catalogue, based on spectroscopic redshifts, from Gloudemans et al (2022).…”

Section: Spectroscopic and Photometric Redshiftsmentioning

confidence: 99%

The LOFAR Two-Metre Sky Survey

Hardcastle,

Horton,

Williams

et al. 2023

A&A

Self Cite

View full text Add to dashboard Cite

The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of ~5700 deg1. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical identifications of a large fraction of the detected radio sources without further radio followup; however, the process is made more challenging by the many extended radio sources found in LOFAR images as a result of its excellent sensitivity to extended structure. In this paper we present source associations and identifications for sources in the second data release based on optical and near-infrared data, using a combination of a likelihood-ratio cross-match method developed for our first data release, our citizen science project Radio Galaxy Zoo: LOFAR, and new approaches to algorithmic optical identification, together with extensive visual inspection by astronomers. We also present spectroscopic or photometric redshifts for a large fraction of the optical identifications. In total 4 116 934 radio sources lie in the area with good optical data, of which 85% have an optical or infrared identification and 58% have a good redshift estimate. We demonstrate the quality of the dataset by comparing it with earlier optically identified radio surveys. This is by far the largest ever optically identified radio catalogue, and will permit robust statistical studies of star-forming and radio-loud active galaxies.

show abstract

Discovery of 24 radio-bright quasars at 4.9 ≤ z ≤ 6.6 using low-frequency radio observations

Cited by 18 publications

References 147 publications

The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5

The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5

DESI z ≳ 5 Quasar Survey. I. A First Sample of 400 New Quasars at z ∼ 4.7–6.6

The LOFAR Two-Metre Sky Survey

Contact Info

Product

Resources

About