Outputs (331)

The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342 (2017)
Journal Article
Kynoch, D., Landt, H., Ward, M. J., Done, C., Gardner, E., Boisson, C., …Pereira Santaella, M. (2018). The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342. Monthly Notices of the Royal Astronomical Society, 475(1), 404-423. https://doi.org/10.1093/mnras/stx3161

The detection of several radio-loud narrow-line Seyfert 1 (NLS1) galaxies by the Fermi Gamma-Ray Space Telescope hints at the existence of a rare, new class of γ-ray emitting active galactic nuclei with low black hole masses. Like flat spectrum radio... Read More about The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342.

The broad-band SEDs of four ‘hypervariable’ AGN (2017)
Journal Article
Collinson, J. S., Ward, M. J., Lawrence, A., Bruce, A., MacLeod, C. L., Elvis, M., …Done, C. (2018). The broad-band SEDs of four ‘hypervariable’ AGN. Monthly Notices of the Royal Astronomical Society, 474(3), 3565-3575. https://doi.org/10.1093/mnras/stx2992

We present an optical-to-X-ray spectral analysis of four ‘hypervariable’ AGN (HVAs) discovered by comparing Pan-STARRS data to that from the Sloan Digital Sky Survey over a 10 yr baseline (Lawrence et al.). There is some evidence that these objects a... Read More about The broad-band SEDs of four ‘hypervariable’ AGN.

A population of highly energetic transient events in the centres of active galaxies (2017)
Journal Article
Kankare, E., Kotak, R., Mattila, S., Lundqvist, P., Ward, M., Fraser, M., …Waters, C. (2017). A population of highly energetic transient events in the centres of active galaxies. Nature Astronomy, 1(12), 865-871. https://doi.org/10.1038/s41550-017-0290-2

Recent all-sky surveys have led to the discovery of new types of transients. These include stars disrupted by the central supermassive black hole, and supernovae that are 10–100 times more energetic than typical ones. However, the nature of even more... Read More about A population of highly energetic transient events in the centres of active galaxies.

Determining the torus covering factors for a sample of type 1 AGN in the local Universe (2017)
Journal Article
Ezhikode, S. H., Gandhi, P., Done, C., Ward, M., Dewangan, G. C., Misra, R., & Philip, N. S. (2017). Determining the torus covering factors for a sample of type 1 AGN in the local Universe. Monthly Notices of the Royal Astronomical Society, 472(3), 3492-3511. https://doi.org/10.1093/mnras/stx2160

In the unified scheme of active galactic nuclei, a dusty torus absorbs and then reprocesses a fraction of the intrinsic luminosity which is emitted at longer wavelengths. Thus, subject to radiative transfer corrections, the fraction of the sky covere... Read More about Determining the torus covering factors for a sample of type 1 AGN in the local Universe.

Super-Eddington QSO RX J0439.6-5311 – II. Multiwavelength constraints on the global structure of the accretion flow (2017)
Journal Article
Jin, C., Done, C., Ward, M., & Gardner, E. (2017). Super-Eddington QSO RX J0439.6-5311 – II. Multiwavelength constraints on the global structure of the accretion flow. Monthly Notices of the Royal Astronomical Society, 471(1), 706-721. https://doi.org/10.1093/mnras/stx1634

We present a detailed multiwavelength study of an unobscured, highly super-Eddington Type-1 QSO RX J0439.6-5311. We combine the latest XMM–Newton observation with all archival data from infrared to hard X-rays. The optical spectrum is very similar to... Read More about Super-Eddington QSO RX J0439.6-5311 – II. Multiwavelength constraints on the global structure of the accretion flow.

The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei (2017)
Journal Article
García-Bernete, I., Ramos Almeida, C., Landt, H., Ward, M., Baloković, M., & Acosta-Pulido, J. (2017). The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 469(1), 110-126. https://doi.org/10.1093/mnras/stx795

We use new X-ray data obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR), near-infrared (NIR) fluxes and mid-infrared (MIR) spectra of a sample of 24 unobscured type 1 active galactic nuclei (AGN) to study the correlation between variou... Read More about The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei.

Spectral analysis of four ‘hypervariable’ AGN: a micro-needle in the haystack? (2017)
Journal Article
Bruce, A., Lawrence, A., MacLeod, C., Elvis, M., Ward, M., Collinson, J., …Waters, C. (2017). Spectral analysis of four ‘hypervariable’ AGN: a micro-needle in the haystack?. Monthly Notices of the Royal Astronomical Society, 467(2), 1259-1280. https://doi.org/10.1093/mnras/stx168

We analyse four extreme active galactic nuclei (AGN) transients to explore the possibility that they are caused by rare, high-amplitude microlensing events. These previously unknown type-I AGN are located in the redshift range 0.6–1.1 and show change... Read More about Spectral analysis of four ‘hypervariable’ AGN: a micro-needle in the haystack?.

Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy (2016)
Journal Article
Collinson, J., Ward, M., Landt, H., Done, C., Elvis, M., & McDowell, J. (2017). Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy. Monthly Notices of the Royal Astronomical Society, 465(1), 358-382. https://doi.org/10.1093/mnras/stw2666

We continue our study of the spectral energy distributions (SEDs) of 11 active galactic nuclei (AGN) at 1.5 < z < 2.2, with optical–near-infrared (NIR) spectra, X-ray data and mid-IR photometry. In a previous paper, we presented the observations and... Read More about Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy.

On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342 (2016)
Journal Article
Landt, H., Ward, M., Baloković, M., Kynoch, D., Storchi-Bergmann, T., Boisson, C., …Stern, D. (2017). On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342. Monthly Notices of the Royal Astronomical Society, 464(3), 2565-2576. https://doi.org/10.1093/mnras/stw2447

Narrow-line Seyfert 1 galaxies have been identified by the Fermi Gamma-Ray Space Telescope as a rare class of γ-ray emitting active galactic nuclei. The lowest redshift candidate among them is the source 1H 0323+342. Here we present quasi-simultaneou... Read More about On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342.

TeV γ-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S (2014)
Journal Article
Abramowski, A., Aharonian, F., Ait Benkhali, F., Akhperjanian, A., Angüner, E., Anton, G., …Zechlin, H. (2014). TeV γ-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S. Monthly Notices of the Royal Astronomical Society, 441(1), 790-799. https://doi.org/10.1093/mnras/stu459

The non-thermal nature of the X-ray emission from the shell-type supernova remnants (SNRs) G1.9+0.3 and G330.2+1.0 is an indication of intense particle acceleration in the shock fronts of both objects. This suggests that the SNRs are prime candidates... Read More about TeV γ-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S.