A5093538384- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
University of Hertfordshire
2024-2025
ABSTRACT Spectral energy distribution (SED) fitting has been extensively used to determine the nature of faint radio source population. Recent efforts have combined fits from multiple SED-fitting codes account for host galaxy and any active nucleus that may be present. We show it is possible produce similar-quality classifications using a single energy-balance SED code, prospector, model up 26 bands UV–far-infrared aperture-matched photometry ∼31 000 sources in ELAIS-N1 field LOFAR Two-Metre...
ABSTRACT We use new 144 MHz observations over 5634 deg2 from the LOFAR (Low Frequency Array) Two-metre Sky Survey (LoTSS) to compile largest sample of uniformly selected, spectroscopically confirmed quasars 14th data release Sloan Digital (SDSS-DR14). Using classical definition radio loudness, R = log (L1.4GHz/Li), we identify 3697 radio-loud (RL) and 111 132 radio-quiet (RQ) sources at 0.6 < z 3.4. To study their properties, develop a rest-frame spectral stacking algorithm, designed...
Abstract Whether the mass of supermassive black hole (MBH) is directly linked to quasar radio luminosity remains a long-debated issue, and understanding role MBH in evolution quasars pivotal unveiling mechanism AGN feedback. In this work, based on two-component Bayesian model, we examine how affects emission from quasars, separating contributions host galaxy star formation (SF) activity. By modelling flux density distribution Sloan Digital Sky Survey (SDSS) LOFAR Two-metre Data Release 2,...
ABSTRACT We present an analysis of 152 355 radio sources identified in the second data release LOFAR Two Metre Sky Survey (LoTSS-DR2) with Sloan Digital (SDSS) spectroscopic redshifts range $0.00 \lt z 0.57$. Using Monte Carlo simulations, we determine reliability each source exhibiting excess luminosity relative to that predicted from their H $\alpha$ emission, and, for a subset 124 023 combine this measurement full BPT analysis. these two independent diagnostics, hosting supermassive black...
We present a comprehensive study of the physical origin radio emission in optical quasars at redshifts $z<2.5$. focus particularly on associations between compact emission, dust reddening, and outflows identified our earlier work. Leveraging deepest low-frequency data available to date (LoTSS Deep DR1), we achieve detection fractions up 94<!PCT!>, demonstrating virtual ubiquity quasars, continuous distribution loudness. Through analysis properties, combined with spectral energy...
We present a comprehensive study of the physical origin radio emission in optical quasars at redshifts z < 2.5. focus particularly on associations between compact emission, dust reddening, and outflows identified our earlier work. Leveraging deepest low-frequency data available to date (LoTSS Deep DR1), we achieve detection fractions up 94%, demonstrating virtual ubiquity quasars, continuous distribution loudness. Through analysis properties, combined with spectral energy modeling...
We use new 144 MHz observations over 5634 deg$^2$ from the LOFAR Two-metre Sky Survey (LoTSS) to compile largest sample of uniformly-selected, spectroscopically-confirmed quasars 14th data release Sloan Digital (SDSS-DR14). Using classical definition radio-loudness, $R=\log(L_{\rm{1.4GHz}}/L_{i})$, we identify 3,697 radio-loud (RL) and 111,132 radio-quiet (RQ) sources at $0.6<z<3.4$. To study their properties, develop a rest-frame spectral stacking algorithm, designed with forthcoming...
Spectral energy distribution (SED) fitting has been extensively used to determine the nature of faint radio source population. Recent efforts have combined fits from multiple SED-fitting codes account for host galaxy and any active nucleus that may be present. We show it is possible produce similar-quality classifications using a single energy-balance SED code, Prospector, model up 26 bands UV$-$far-infrared aperture-matched photometry $\sim$31,000 sources in ELAIS-N1 field LOFAR Two-Metre...
Abstract Some Active Galactic Nuclei (AGN) host outflows which have the potential to alter galaxy’s evolution (AGN feedback). These been linked enhanced radio emission. Here we investigate connection between low-frequency emission using International LOFAR Telescope and [O iii] λ5007 ionised gas Sloan Digital Sky Survey. Using Two-metre Survey (LoTSS) Deep Fields, select 198 AGN with optical spectra, 115 of are detected at 144 MHz, their properties. The majority our sample do not show a...
Some Active Galactic Nuclei (AGN) host outflows which have the potential to alter galaxy's evolution (AGN feedback). These been linked enhanced radio emission. Here we investigate connection between low-frequency emission using International LOFAR Telescope and [O III] $\lambda$5007 ionised gas Sloan Digital Sky Survey. Using Two-metre Survey (LoTSS) Deep Fields, select 198 AGN with optical spectra, 115 of are detected at 144 MHz, their properties. The majority our sample do not show a...
We characterise the co-evolution of radio-loud AGN and their galaxies by mapping dependence activity on stellar mass star-formation rate (SFR) across cosmic time (out to $z \sim 1.5$). Deep LOFAR radio observations are combined with large galaxy samples study incidence population; further split into low-excitation (LERGs) high-excitation (HERGs). find that LERG occurs over a wide range SFRs, whereas HERGs typically found in ongoing star formation. The LERGs then based SFRs relative main...
ABSTRACT We characterize the co-evolution of radio-loud active galactic nuclei (AGN) and their galaxies by mapping dependence AGN activity on stellar mass star formation rate (SFR) across cosmic time (out to $z \sim 1.5$). Deep LOFAR radio observations are combined with large galaxy samples study incidence population; further split into low-excitation (LERGs) high-excitation (HERGs). find that LERG occurs over a wide range SFRs, whereas HERGs typically found in ongoing formation. The LERGs...
We present a detailed study of the large-scale shock front in Stephan's Quintet, byproduct past and ongoing interactions. Using integral-field spectroscopy from new William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE), recent 144 MHz observations LOFAR Two-metre Sky Survey (LoTSS), archival data Very Large Array James Webb Space (JWST), we obtain measurements key properties determine its impact on system. Harnessing WEAVE large integral field unit's (LIFU) view (90 $\times$ 78...