J/A+A/668/A27 24 new radio-bright quasars spectra (Gloudemans+, 2022)
Discovery of 24 radio-bright quasars at 4.9 ≤ z ≤ 6.6 using low-frequency
radio observations.
Gloudemans A.J., Duncan K.J., Saxena A., Harikane Y., Hill G.J.,
Zeimann G.R., Rottgering H.J.A., Yang D., Best P.N., Banados E., Drabent A.,
Hardcastle M.J., Hennawi J.F., Lansbury G., Magliocchetti M., Miley G.K.,
Nanni R., Shimwell T.W., Smith D.J.B., Venemans B.P., Wagenveld J.D.
<Astron. Astrophys. 668, A27 (2022)>
=2022A&A...668A..27G 2022A&A...668A..27G (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Galaxies, radio ; Optical
Keywords: radio continuum: galaxies - quasars: general -
galaxies: high-redshift - galaxies: active
Abstract:
We present the discovery of 20 new radio bright quasars (and the
independent confirmation of 4) between 4.9<z<6.6. These quasars
have been selected by combining an optical dropout selection driven by
the g-, r-, and z-bands from the Dark Energy Spectroscopic Instrument
(DESI) Legacy Imaging Surveys with low-frequency radio observations
from the LOFAR Two-metre Sky Survey. Our radio detection requirement
strongly decreases the contamination of stellar sources and allows for
selecting these quasars in a broad redshift range. Despite selecting
our quasar candidates using fewer and less conservative colour
restrictions, both the optical and near-infrared colours, Lyα
emission line properties, and dust reddening, E(B-V), measurements of
our quasar sample do not deviate from the known radio-quiet quasar
population, suggesting similar optical quasar properties of the
radio-loud and radio-quiet quasar population at high-z. Our campaign
demonstrates the potential for discovering new high-z quasar
populations through next generation radio continuum surveys.
Description:
Properties of newly discovered high-z quasars derived from photometric
and spectroscopic observations. The radio measurements have been
obtained using the LOFAR Two Metre Sky Survey (LoTSS-DR2; 144MHz),
VLA FIRST (1.4GHz), and Very Large Array Sky Survey (VLASS; 2-4GHz).
The spectroscopic observations have been conducted using the Faint
Object Camera and Spectrograph on the Subaru telescope, LRS2 on the
Hobby-Eberly Telescope, and LRIS on Keck. The rest-frame UV magnitudes
have been derived by combining the optical to mid-infrared
observations and performing spectral energy distribution fitting using
the template fitting code EAZY (Brammer et al., 2008ApJ...686.1503B 2008ApJ...686.1503B).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 306 24 Measurements of high-z quasars
list.dat 94 25 List of fits spectra
fits/* . 25 Individual fits spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name
15- 28 F14.10 deg RAdeg Optical right ascension
Legacy Surveys DR8 (J2000.0)
30- 42 F13.10 deg DEdeg Optical declination
Legacy Surveys DR8 (J2000.0)
44- 57 F14.10 deg RALdeg Right ascension from LoTSS-DR2 (J2000.0)
59- 71 F13.10 deg DELdeg Declination from LoTSS-DR2 (J2000.0)
73- 76 F4.2 --- zsp Spectroscopic redshift
78- 81 F4.2 --- e_zsp Spectroscopic redshift error
83- 87 F5.2 mJy F144MHz Total flux at 144MHz
89- 92 F4.2 mJy e_F144MHz Total flux err at 144MHz
94-101 E8.3 W/Hz L144MHz Radio luminosity at 144MHz
103-110 E8.3 W/Hz e_L144MHz Radio luminosity error at 144MHz
112-117 F6.2 mJy F1.4GHz ?=-99 Total flux FIRST at 1.4GHz
119-124 F6.2 mJy e_F1.4GHz ?=-99 Total flux error FIRST at 1.4GHz
126-131 F6.2 mJy F3GHz ?=-99 Total flux VLASS at 3GHz
133-138 F6.2 mJy e_F3GHz ?=-99 Total flux error VLASS at 3GHz
140-145 F6.2 --- alphaLF ?=-99 Spectral index between 144MHz-1.4GHz
(LOFAR-VLASS)
147-152 F6.2 --- e_alphaLF ?=-99 Spectral index error between
144MHz-1.4GHz (LOFAR-VLASS)
154-159 F6.2 --- alphaFV ?=-99 Spectral index between 1.4GHz-3GHz
(FIRST-VLASS)
161-166 F6.2 --- e_alphaFV ?=-99 Spectral index error between
1.4GHz-3GHz (FIRST-VLASS)
168-173 F6.2 --- alphaLV ?=-99 Spectral index between 144MHz-3GHz
(LOFAR-VLASS)
175-180 F6.2 --- e_alphaLV ?=-99 Spectral index error between
144MHz-3GHz (LOFAR-VLASS)
182-188 F7.2 --- R5GHz Radio-loudness f5GHz/f4400Å
190-195 F6.2 --- e_R5GHz Radio-loudness error
197-204 E8.3 10-7W b_LLya Lyα luminosity 16th percentile in erg/s
206-213 E8.3 10-7W LLya Lyα luminosity 50th percentile in erg/s
215-222 E8.3 10-7W B_LLya Lyα luminosity 84th percentile in erg/s
224-229 F6.2 0.1nm b_EWLya Equivalent width Lyα 16th percentile
231-236 F6.2 0.1nm EWLya Equivalent width Lyα 50th percentile
238-243 F6.2 0.1nm B_EWLya Equivalent width Lyα 84th percentile
245-250 F6.2 mag b_M1450 Absolute magnitude at 1450Å 16th percentile
252-257 F6.2 mag M1450 Absolute magnitude at 1450Å 50th percentile
259-264 F6.2 mag B_M1450 Absolute magnitude at 1450Å 84th percentile
266-271 F6.2 mag b_M2500 Absolute magnitude at 2500Å 16th percentile
273-278 F6.2 mag M2500 Absolute magnitude at 2500Å 50th percentile
280-285 F6.2 mag B_M2500 Absolute magnitude at 2500Å 84th percentile
287-292 F6.2 mag b_M4400 Absolute magnitude at 4000Å 16th percentile
294-299 F6.2 mag M4400 Absolute magnitude at 4000Å 50th percentile
301-306 F6.2 mag B_M4400 Absolute magnitude at 4000Å 84th percentile
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name
15- 28 F14.10 deg RAdeg Right ascension (J2000.0)
30- 42 F13.10 deg DEdeg Declination (J2000.0)
44- 53 A10 "date" Obs.date Observations date (DD-MM-YYYY)
55- 59 A5 --- Inst Name of instrument
61- 66 A6 --- Tel Name of telescope
68- 94 A27 --- FileName Name of FITS spectrum in subdirectory fits
--------------------------------------------------------------------------------
Acknowledgements:
Anniek Gloudemans, gloudemans(at)strw.leidenuniv.nl
(End) Anniek Gloudemans [Leiden University], Patricia Vannier [CDS] 03-Oct-2022