The spectral energy distributions of active galactic nuclei

Brown, M. J. I.; Duncan, K. J.; Landt, Hermine; Kirk, Michael; Ricci, Cláudio; Kamraj, Nikita; Salvato, M.; Ananna, Tonima Tasnim

doi:10.1093/mnras/stz2324

Cited by 38 publications

(38 citation statements)

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“…Furthermore, we also find an increased agreement between the observed stellar mass functions (SMFs) between fields and with those available in the literature. We note that when fitting stellar masses using the zeropoint corrections derived from the photo-z estimates (specifically the combined template sets of Brown et al 2014Brown et al , 2019, we find no systematic offset in the resulting stellar masses -with a median offset of 0.03 dex, significantly smaller than the typical uncertainty on individual estimates.…”

Section: Flux Zero-point and Total Flux Correctionsmentioning

confidence: 61%

“…We note however that model uncertainties estimated by this method are representative of the average uncertainty across the full template set given the spectroscopic sample available. As demonstrated by Brown et al (2019), the model uncertainties for known AGN samples can be substantially larger at certain rest-frame wavelengths. However, a full Bayesian template fitting framework that can account for variance associated with each individual template (see e.g.…”

Section: Template Model Uncertaintiesmentioning

confidence: 96%

“…Extended Atlas Library: The second template set, the 'Atlas of Empirical SEDs ' Brown et al (2014) was recently extended to incorporate a wide range of the AGN and quasistellar object (QSO) populations not previously present in the original library (Brown et al 2019). Additionally, the new Atlas of AGN SEDs incorporates a range of combinations of Seyfert type AGN spectra and different underlying host stellar populations (with varying AGN to host contributions).…”

Section: Template Fittingmentioning

confidence: 99%

“…Additionally, the new Atlas of AGN SEDs incorporates a range of combinations of Seyfert type AGN spectra and different underlying host stellar populations (with varying AGN to host contributions). As illustrated in Brown et al (2019), the inclusion of a fully representative range of AGN SEDs (and combinations of AGN + host galaxy) leads to significant improvement in the photo-z statistics for AGN dominated galaxies -the area for which machine learning estimates were found to provide the greatest improvement in the hybrid method (? ).…”

Section: Template Fittingmentioning

confidence: 99%

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The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

Duncan

Kondapally

Brown

et al. 2021

A&A

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The Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey split across multiple tiers over the northern sky. The first LoTSS Deep Fields data release consists of deep radio continuum imaging at 150 MHz of the Boötes, European Large Area Infrared Space Observatory Survey-North 1 (ELAIS-N1), and Lockman Hole fields, down to rms sensitivities of ∼32, 20, and 22 µJy beam −1 , respectively. In this paper we present consistent photometric redshift (photo-z) estimates for the optical source catalogues in all three fields-totalling over 7 million sources (∼ 5 million after limiting to regions with the best photometric coverage). Our photo-z estimation uses a hybrid methodology that combines template fitting and machine learning and is optimised to produce the best possible performance for the radio continuum selected sources and the wider optical source population. Comparing our results with spectroscopic redshift samples, we find a robust scatter ranging from 1.6 to 2% for galaxies and 6.4 to 7% for identified optical, infrared, or X-ray selected active galactic nuclei (AGN). Our estimated outlier fractions (z phot − z spec /(1 + z spec) > 0.15) for the corresponding subsets range from 1.5 to 1.8% and 18 to 22%, respectively. Replicating trends seen in analyses of previous wide-area radio surveys, we find no strong trend in photo-z quality as a function of radio luminosity for a fixed redshift. We exploit the broad wavelength coverage available within each field to produce galaxy stellar mass estimates for all optical sources at z < 1.5. Stellar mass functions derived for each field are used to validate our mass estimates, with the resulting estimates in good agreement between each field and with published results from the literature.

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Section: Flux Zero-point and Total Flux Correctionsmentioning

confidence: 61%

Section: Template Model Uncertaintiesmentioning

confidence: 96%

Section: Template Fittingmentioning

confidence: 99%

Section: Template Fittingmentioning

confidence: 99%

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The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

Duncan

Kondapally

Brown

et al. 2021

A&A

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“…Regular members of the extragalactic zoo, the Active Galactic Nuclei (AGN) are notably strong sources with a spectral energy distribution (SED) ranging from gamma to radio wavelengths (Brown et al, 2019); generally, the SED presents a peak at UV and significant luminosity contribution at the infrared and X-rays wavelengths. Radio galaxies are a subclass of AGNs.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the double-lobed sources of the Cygnus constellation core

Saponara

Benaglia

Andruchow

et al. 2021

Publ. Astron. Soc. Aust.

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We present a collection of double-lobed sources towards a $20\,\mathrm{deg}^2$ area of the Cygnus region at the northern sky, observed at 325 and 610 MHz with the Giant Metrewave Radio Telescope. The 10 $^{\prime\prime}$ resolution achieved at 325 MHz is 5.5 times better than previous studies, while at 610 MHz, these are the first results ever of such a large area, mapped with 6 $^{\prime\prime}$ angular resolution. After a thorough visual inspection of the images at the two bands, we found 43 double-lobed source candidates, proposed as such due to the presence of 2 bright peaks, within a few arcminutes apart, joined by a bridge or a central nucleus. All but two are presented here as a double-lobed candidates for the first time. Thirty nine of the candidates were covered at both bands, and we provide the spectral index information for them. We have searched for positional coincidences between the detected sources/components and other objects from the literature, along the electromagnetic spectrum. Twenty-three candidates possess radio counterpart(s), 12 present infrared counterparts, and 1 showed an overlapping X-ray source. We analysed each candidate considering morphology, counterparts, and spectral indices. Out of the 43 candidates, 37 show characteristics compatible with an extragalactic nature, 2 of probably Galactic origin, 3 remain as dubious cases, though with feature(s) compatible with an extragalactic nature, and the remaining one, evidence of physically unrelated components. The median spectral index of the 40 putative extragalactic sources is $-1.0$ . Their celestial surface density at 610 MHz resulted in $1.9\,\mathrm{per\ deg}^2$ , across a region lying at the Galactic plane.

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The eROSITA Final Equatorial-Depth Survey (eFEDS)

Salvato

Wolf

Dwelly

et al. 2022

A&A

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Context. In November 2019, eROSITA on board of the Spektrum-Roentgen-Gamma (SRG) observatory started to map the entire sky in X-rays. After the four-year survey program, it will reach a flux limit that is about 25 times deeper than ROSAT. During the SRG performance verification phase, eROSITA observed a contiguous 140 deg2 area of the sky down to the final depth of the eROSITA all-sky survey (eROSITA Final Equatorial-Depth Survey; eFEDS), with the goal of obtaining a census of the X-ray emitting populations (stars, compact objects, galaxies, clusters of galaxies, and active galactic nuclei) that will be discovered over the entire sky. Aims. This paper presents the identification of the counterparts to the point sources detected in eFEDS in the main and hard samples and their multi-wavelength properties, including redshift. Methods. To identifyy the counterparts, we combined the results from two independent methods (NWAY and ASTROMATCH), trained on the multi-wavelength properties of a sample of 23k XMM-Newton sources detected in the DESI Legacy Imaging Survey DR8. Then spectroscopic redshifts and photometry from ancillary surveys were collated to compute photometric redshifts. Results. Of the eFEDS sources, 24 774 of 27 369 have reliable counterparts (90.5%) in the main sample and 231 of 246 sourcess (93.9%) have counterparts in the hard sample, including 2514 (3) sources for which a second counterpart is equally likely. By means of reliable spectra, Gaia parallaxes, and/or multi-wavelength properties, we have classified the reliable counterparts in both samples into Galactic (2695) and extragalactic sources (22 079). For about 340 of the extragalactic sources, we cannot rule out the possibility that they are unresolved clusters or belong to clusters. Inspection of the distributions of the X-ray sources in various optical/IR colour-magnitude spaces reveal a rich variety of diverse classes of objects. The photometric redshifts are most reliable within the KiDS/VIKING area, where deep near-infrared data are also available. Conclusions. This paper accompanies the eROSITA early data release of all the observations performed during the performance and verification phase. Together with the catalogues of primary and secondary counterparts to the main and hard samples of the eFEDS survey, this paper releases their multi-wavelength properties and redshifts.

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The spectral energy distributions of active galactic nuclei

Cited by 38 publications

References 100 publications

The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1

Investigation of the double-lobed sources of the Cygnus constellation core

The eROSITA Final Equatorial-Depth Survey (eFEDS)

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