All Outputs (287)

The VST ATLAS quasar survey I: Catalogue of photometrically selected quasar candidates (2023)
Journal Article
Eltvedt, A. M., Shanks, T., Metcalfe, N., Ansarinejad, B., Barrientos, L., Sharp, R., …Zhou, Z. (2023). The VST ATLAS quasar survey I: Catalogue of photometrically selected quasar candidates. Monthly Notices of the Royal Astronomical Society, 521(3), 3384-3404. https://doi.org/10.1093/mnras/stad516

We present the VST ATLAS Quasar Survey, consisting of ∼1229 000 quasar (QSO) candidates with 16 < g < 22.5 over ∼4700 deg2. The catalogue is based on VST ATLAS+NEOWISE imaging surveys and aims to reach a QSO sky density of 130 deg−2 for z < 2.2 and ∼... Read More about The VST ATLAS quasar survey I: Catalogue of photometrically selected quasar candidates.

VST ATLAS galaxy cluster catalogue I: cluster detection and mass calibration (2023)
Journal Article
Ansarinejad, B., Murphy, D., Shanks, T., & Metcalfe, N. (2023). VST ATLAS galaxy cluster catalogue I: cluster detection and mass calibration. Monthly Notices of the Royal Astronomical Society, 520(1), 1371-1389. https://doi.org/10.1093/mnras/stac3815

Taking advantage of ∼4700 deg2 optical coverage of the Southern sky offered by the VST ATLAS survey, we construct a new catalogue of photometrically selected galaxy groups and clusters using the ORCA cluster detection algorithm. The catalogue contain... Read More about VST ATLAS galaxy cluster catalogue I: cluster detection and mass calibration.

The local hole: a galaxy underdensity covering 90 per cent of sky to ≈200 Mpc (2022)
Journal Article
Wong, J. H., Shanks, T., Metcalfe, N., & Whitbourn, J. (2022). The local hole: a galaxy underdensity covering 90 per cent of sky to ≈200 Mpc. Monthly Notices of the Royal Astronomical Society, 511(4), 5742-5755. https://doi.org/10.1093/mnras/stac396

We investigate the ‘Local Hole’, an anomalous underdensity in the local galaxy environment, by extending our previous galaxy K-band number-redshift and number-magnitude counts to ≈90 per cent of the sky. Our redshift samples are taken from the 2MASS... Read More about The local hole: a galaxy underdensity covering 90 per cent of sky to ≈200 Mpc.

The nature of sub-millimetre galaxies II: an ALMA comparison of SMG dust heating mechanisms (2022)
Journal Article
Ansarinejad, B., Shanks, T., Bielby, R., Metcalfe, N., Infante, L., Murphy, D., …Stach, S. (2022). The nature of sub-millimetre galaxies II: an ALMA comparison of SMG dust heating mechanisms. Monthly Notices of the Royal Astronomical Society, 510(4), 4976-4991. https://doi.org/10.1093/mnras/stac002

We compare the contribution of active galactic nuclei (AGNs) and star formation towards dust heating in sub-mm galaxies (SMGs). We have used ALMA at 0.1-arcsec resolution to image a complete flux-limited sample of seven sub-mm sources previously show... Read More about The nature of sub-millimetre galaxies II: an ALMA comparison of SMG dust heating mechanisms.

A meeting at z ∼ 3: Young massive galaxies and an AGN within 30 kpc of the luminous QSO LBQS 0302–0019 (2021)
Journal Article
Husemann, B., Worseck, G., Arrigoni Battaia, F., Sander, A., & Shanks, T. (2021). A meeting at z ∼ 3: Young massive galaxies and an AGN within 30 kpc of the luminous QSO LBQS 0302–0019. Astronomy & Astrophysics, 653, Article A122. https://doi.org/10.1051/0004-6361/202140898

Context. Contrary to expectations from scenarios of black hole growth driven by galaxy interactions and mergers, dual active galactic nuclei (AGN) with kiloparsec separations are rarely observed and are very difficult to identify, in particular at hi... Read More about A meeting at z ∼ 3: Young massive galaxies and an AGN within 30 kpc of the luminous QSO LBQS 0302–0019.

The nature of sub-millimetre galaxies I: a comparison of AGN and star-forming galaxy SED fits (2021)
Journal Article
Shanks, T., Ansarinejad, B., Bielby, R., Heywood, I., Metcalfe, N., & Wang, L. (2021). The nature of sub-millimetre galaxies I: a comparison of AGN and star-forming galaxy SED fits. Monthly Notices of the Royal Astronomical Society, 505(1), 1509-1529. https://doi.org/10.1093/mnras/stab1226

High-redshift sub-millimetre galaxies (SMGs) are usually assumed to be powered by star formation. However, it has been clear for some time that >20 per cent of such sourcesbrighter than ≈3 mJy host quasars. Here, we analyse a complete sample of 12 su... Read More about The nature of sub-millimetre galaxies I: a comparison of AGN and star-forming galaxy SED fits.

Erratum: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars (2021)
Journal Article
Shajib, A., Birrer, S., Treu, T., Auger, M., Agnello, A., Anguita, T., …Walker, A. (2021). Erratum: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars. Monthly Notices of the Royal Astronomical Society, 501(2), 2833-2835. https://doi.org/10.1093/mnras/staa3562

The paper ‘Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars’ was published in MNRAS, 483, 4, 5649–5671 (2019). The coordinate values of the image positions in table 4 were wrongly printe... Read More about Erratum: Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars.

Cross-correlating Planck with VST ATLAS LRGs: a new test for the ISW effect in the Southern Hemisphere (2020)
Journal Article
Ansarinejad, B., Mackenzie, R., shanks, T., & Metcalfe, N. (2020). Cross-correlating Planck with VST ATLAS LRGs: a new test for the ISW effect in the Southern Hemisphere. Monthly Notices of the Royal Astronomical Society, 493(4), 4830-4844. https://doi.org/10.1093/mnras/staa592

The Integrated Sachs-Wolfe (ISW) effect probes the late-time expansion history of the universe, offering direct constraints on dark energy. Here we present our measurements of the ISW signal at redshifts of z¯=0.35⁠, 0.55 and 0.68, using the cross-co... Read More about Cross-correlating Planck with VST ATLAS LRGs: a new test for the ISW effect in the Southern Hemisphere.

Local Hole revisited: evidence for bulk motions and self-consistent outflow (2019)
Journal Article
Shanks, T., Hogarth, L., Metcalfe, N., & Whitbourn, J. (2019). Local Hole revisited: evidence for bulk motions and self-consistent outflow. Monthly Notices of the Royal Astronomical Society, 490(4), 4715-4720. https://doi.org/10.1093/mnras/stz2863

We revisit our mapping of the ‘Local Hole’, a large underdensity in the local galaxy redshift distribution that extends out to redshift, z ≈ 0.05 and a potential source of outflows that may perturb the global expansion rate and thus help mitigate the... Read More about Local Hole revisited: evidence for bulk motions and self-consistent outflow.

Gaia Cepheid parallaxes and ‘Local Hole’ relieve H0 tension (2018)
Journal Article
Shanks, T., Hogarth, L., & Metcalfe, N. (2019). Gaia Cepheid parallaxes and ‘Local Hole’ relieve H0 tension. Monthly Notices of the Royal Astronomical Society: Letters, 484(1), L64-L68. https://doi.org/10.1093/mnrasl/sly239

There is an ≈9 ± 2.5 per cent tension between the value of Hubble’s Constant, H0 = 67.4 ± 0.5 km s−1 Mpc−1, implied by the Planck microwave background power spectrum and that given by the distance scale of H0 = 73.4 ± 1.7 km s−1Mpc−1. But with a plau... Read More about Gaia Cepheid parallaxes and ‘Local Hole’ relieve H0 tension.

Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars (2018)
Journal Article
Shajib, A., Birrer, S., Treu, T., Auger, M., Agnello, A., Anguita, T., …Walker, A. (2019). Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars. Monthly Notices of the Royal Astronomical Society, 483(4), 5649-5671. https://doi.org/10.1093/mnras/sty3397

Strong-gravitational lens systems with quadruply imaged quasars (quads) are unique probes to address several fundamental problems in cosmology and astrophysics. Although they are intrinsically very rare, ongoing and planned wide-field deep-sky survey... Read More about Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars.

Detection significance of baryon acoustic oscillations peaks in galaxy and quasar clustering (2018)
Journal Article
Ansarinejad, B., & Shanks, T. (2018). Detection significance of baryon acoustic oscillations peaks in galaxy and quasar clustering. Monthly Notices of the Royal Astronomical Society, 479(3), 4091-4107. https://doi.org/10.1093/mnras/sty1740

We compare our analysis of the baryon acoustic oscillations (BAO) feature in the correlation functions of SDSS BOSS DR12 LOWZ and CMASS galaxy samples with previous literature results. Using subsets of the data we obtain an empirical estimate of the... Read More about Detection significance of baryon acoustic oscillations peaks in galaxy and quasar clustering.

Cosmic dance at z ~ 3: Detecting the host galaxies of the dual AGN system LBQS 0302–0019 and Jil with HAWK-I+GRAAL (2018)
Journal Article
Husemann, B., Bielby, R., Jahnke, K., Arrigoni-Battaia, F., Worseck, G., Shanks, T., …Scholtz, J. (2018). Cosmic dance at z ~ 3: Detecting the host galaxies of the dual AGN system LBQS 0302–0019 and Jil with HAWK-I+GRAAL. Astronomy & Astrophysics, 614, Article L2. https://doi.org/10.1051/0004-6361/201833363

We recently discovered that the luminous radio-quiet quasi-stellar objects (QSO) LBQS 0302–0019 at z = 3.286 is likely accompanied by an obscured AGN at 20 kpc projected distance, which we dubbed Jil. It represents the tightest candidate system of an... Read More about Cosmic dance at z ~ 3: Detecting the host galaxies of the dual AGN system LBQS 0302–0019 and Jil with HAWK-I+GRAAL.

Quasars Probing Quasars. X. The Quasar Pair Spectral Database (2018)
Journal Article
Findlay, J. R., Prochaska, J. X., Hennawi, J. F., Fumagalli, M., Myers, A. D., Bartle, S., …Rubin, K. H. (2018). Quasars Probing Quasars. X. The Quasar Pair Spectral Database. Astrophysical Journal Supplement, 236(2), Article 44. https://doi.org/10.3847/1538-4365/aabee5

The rare close projection of two quasars on the sky provides the opportunity to study the host galaxy environment of a foreground quasar in absorption against the continuum emission of a background quasar. For over a decade the "Quasars probing quasa... Read More about Quasars Probing Quasars. X. The Quasar Pair Spectral Database.

Discovery of a dual AGN at z ≃ 3.3 with 20 kpc separation (2018)
Journal Article
Husemann, B., Worseck, G., Arrigoni Battaia, F., & Shanks, T. (2018). Discovery of a dual AGN at z ≃ 3.3 with 20 kpc separation. Astronomy & Astrophysics, 610, Article L7. https://doi.org/10.1051/0004-6361/201732457

A prediction of the current paradigm of the hierarchical assembly of galaxies is the presence of supermassive dual black holes at separations of a few kpc or less. In this context, we report the detection of a narrow-line emitter within the extended... Read More about Discovery of a dual AGN at z ≃ 3.3 with 20 kpc separation.

Quasar lenses and pairs in the VST-ATLAS and Gaia (2017)
Journal Article
Agnello, A., Schechter, P., Morgan, N., Treu, T., Grillo, C., Malesani, D., …Shanks, T. (2018). Quasar lenses and pairs in the VST-ATLAS and Gaia. Monthly Notices of the Royal Astronomical Society, 475(2), 2086-2096. https://doi.org/10.1093/mnras/stx3226

We report on discovery results from a quasar lens search in the ATLAS-DR3 public footprint. Spectroscopic follow-up campaigns, conducted at the 2.6 m Nordic Optical Telescope (La Palma) and 3.6 m New Technology Telescope (La Silla) in 2016, yielded s... Read More about Quasar lenses and pairs in the VST-ATLAS and Gaia.

The VLT LBG redshift survey – VI. Mapping H i in the proximity of z ∼ 3 LBGs with X-Shooter (2017)
Journal Article
Bielby, R., Shanks, T., Crighton, N., Bornancini, C., Infante, L., Lambas, D., …Tummuangpak, P. (2017). The VLT LBG redshift survey – VI. Mapping H i in the proximity of z ∼ 3 LBGs with X-Shooter. Monthly Notices of the Royal Astronomical Society, 471(2), 2174-2186. https://doi.org/10.1093/mnras/stx1772

We present an analysis of the spatial distribution and dynamics of neutral hydrogen gas around galaxies using new X-Shooter observations of z ∼ 2.5–4 quasars. Adding the X-Shooter data to our existing data set of high-resolution quasar spectroscopy,... Read More about The VLT LBG redshift survey – VI. Mapping H i in the proximity of z ∼ 3 LBGs with X-Shooter.

Evidence against a supervoid causing the CMB Cold Spot (2017)
Journal Article
Mackenzie, R., Shanks, T., Bremer, M. N., Cai, Y., Gunawardhana, M. L., Kovács, A., …Szapudi, I. (2017). Evidence against a supervoid causing the CMB Cold Spot. Monthly Notices of the Royal Astronomical Society, 470(2), 2328-2338. https://doi.org/10.1093/mnras/stx931

We report the results of the 2dF-VST ATLAS Cold Spot galaxy redshift survey (2CSz) based on imaging from VST ATLAS and spectroscopy from 2dF AAOmega over the core of the CMB Cold Spot. We sparsely surveyed the inner 5° radius of the Cold Spot to a li... Read More about Evidence against a supervoid causing the CMB Cold Spot.

First Lensed Quasar Systems from the VST-ATLAS Survey: One Quad, Two Doubles, and Two Pairs of Lensless Twins (2017)
Journal Article
Schechter, P., Morgan, N., Chehade, B., Metcalfe, N., Shanks, T., & McDonald, M. (2017). First Lensed Quasar Systems from the VST-ATLAS Survey: One Quad, Two Doubles, and Two Pairs of Lensless Twins. Astronomical Journal, 153(5), Article 219. https://doi.org/10.3847/1538-3881/aa6899

We have analyzed images from the VST-ATLAS survey to identify candidate gravitationally lensed quasar systems in a sample of WISE sources with $W1-W2\gt 0.7$. Results from follow-up spectroscopy with the Baade 6.5 m telescope are presented for eight... Read More about First Lensed Quasar Systems from the VST-ATLAS Survey: One Quad, Two Doubles, and Two Pairs of Lensless Twins.

First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey (2017)
Journal Article
Wang, F., Fan, X., Yang, J., Wu, X., Yang, Q., Bian, F., …Shanks, T. (2017). First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey. Astrophysical Journal, 839(1), Article 27. https://doi.org/10.3847/1538-4357/aa689f

We present the first discoveries from a survey of z gsim 6 quasars using imaging data from the DECam Legacy Survey (DECaLS) in the optical, the UKIRT Deep Infrared Sky Survey (UKIDSS) and a preliminary version of the UKIRT Hemisphere Survey (UHS) in... Read More about First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey.