All Outputs (340)

Nuclear Infrared Spectral Energy Distribution of Type II Active Galactic Nuclei (2013)
Journal Article
Videla, L., Lira, P., Andrews, H., Alonso-Herrero, A., Alexander, D., & Ward, M. (2013). Nuclear Infrared Spectral Energy Distribution of Type II Active Galactic Nuclei. Astrophysical Journal Supplement, 204(2), https://doi.org/10.1088/0067-0049/204/2/23

We present near- and mid-IR observations of a sample of Seyfert II galaxies drawn from the 12 μm Galaxy sample. The sample was observed in the J, H, K, L, M and N bands. Galaxy surface brightness profiles are modeled using nuclear, bulge, bar (when n... Read More about Nuclear Infrared Spectral Energy Distribution of Type II Active Galactic Nuclei.

Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., Balenderan, S., …Zechlin, H. (2013). Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S. Astronomy & Astrophysics, 550, Article A4. https://doi.org/10.1051/0004-6361/201220355

The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the EBL opacity to γ-rays on th... Read More about Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S.

Relation between X-ray and optical spectra (Jin+, 2012) (2013)
Journal Article
Jin, C., Ward, M., & Done, C. (2013). Relation between X-ray and optical spectra (Jin+, 2012)

Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., Balenderan, S., …Zechlin, H. (2013). Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S. Physical Review Letters, 110(4), Article 041301. https://doi.org/10.1103/physrevlett.110.041301

Gamma-ray line signatures can be expected in the very-high-energy (Eγ>100  GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in m... Read More about Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S.

A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling (2012)
Journal Article
Jin, C., Ward, M., Done, C., & Gelbord, J. (2012). A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling. Monthly Notices of the Royal Astronomical Society, 420(3), 1825-1847. https://doi.org/10.1111/j.1365-2966.2011.19805.x

We present modelling and interpretation of the continuum and emission lines for a sample of 51 unobscured type 1 active galactic nuclei (AGNs). All of these AGNs have high-quality spectra from both XMM–Newton and the Sloan Digital Sky Survey. We exte... Read More about A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling.

The near-infrared broad emission line region of active galactic nuclei – II. The 1-μm continuum (2011)
Journal Article
Landt, H., Martin, E., Ward, M. J., Bentz, M. C., Korista, K. T., & Karovska, M. (2011). The near-infrared broad emission line region of active galactic nuclei – II. The 1-μm continuum. Monthly Notices of the Royal Astronomical Society, 414(1), 218-240. https://doi.org/10.1111/j.1365-2966.2011.18383.x

We use quasi-simultaneous near-infrared (near-IR) and optical spectroscopy from four observing runs to study the continuum around 1 μm in 23 well-known broad emission line active galactic nuclei (AGN). We show that, after correcting the optical spect... Read More about The near-infrared broad emission line region of active galactic nuclei – II. The 1-μm continuum.

The location and kinematics of the coronal-line emitting regions in active galactic nuclei. (2009)
Journal Article
Mullaney, J., Ward, M., Done, C., Ferland, G., & Schurch, N. (2009). in active galactic nuclei. Monthly Notices of the Royal Astronomical Society: Letters, 394(1), 16-20. https://doi.org/10.1111/j.1745-3933.2008.00599.x

Spectrum and variability of the Galactic center VHE gamma-ray source HESS J1745-290 (2009)
Journal Article
Aharonian, F., Akhperjanian, A., Anton, G., Barres de Almeida, U., Bazer-Bachi, A., Becherini, Y., …Zech, A. (2009). Spectrum and variability of the Galactic center VHE gamma-ray source HESS J1745-290. Astronomy and Astrophysics, 503(3), 817-825. https://doi.org/10.1051/0004-6361/200811569

The Seyfert AGN RX J0136.9-3510 and the spectral state of super Eddington accretion flows (2009)
Journal Article
Jin, C., Done, C., Ward, M., Gierliński, M., & Mullaney, J. (2009). The Seyfert AGN RX J0136.9-3510 and the spectral state of super Eddington accretion flows. Monthly Notices of the Royal Astronomical Society: Letters, 398, L16-L20. https://doi.org/10.1111/j.1745-3933.2009.00697.x

A Compton-thick Wind in the High-luminosity Quasar, PDS 456 (2009)
Journal Article
Reeves, J., O'Brien, P., Braito, V., Behar, E., Miller, L., Turner, T., …Ward, M. (2009). A Compton-thick Wind in the High-luminosity Quasar, PDS 456. Astrophysical Journal, 701, 493-507. https://doi.org/10.1088/0004-637x/701/1/493

Optical emission-line properties of narrow-line Seyfert 1 galaxies and comparison active galactic nuclei (2008)
Journal Article
Mullaney, J., & Ward, M. (2008). Optical emission-line properties of narrow-line Seyfert 1 galaxies and comparison active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 385(1), 53-74. https://doi.org/10.1111/j.1365-2966.2007.12777.x

A periodicity of ~1 hour in X-ray emission from the active galaxy RE J1034+396 (2008)
Journal Article
Gierliński, M., Middleton, M., Ward, M., & Done, C. (2008). A periodicity of ~1 hour in X-ray emission from the active galaxy RE J1034+396. Nature, 455(7211), 369-371. https://doi.org/10.1038/nature07277

Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2 (2007)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2007). Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2. Astronomy & Astrophysics, 467(3), 1075-1080. https://doi.org/10.1051/0004-6361%3A20066950

Aims. Results from $\gamma$-ray observations by the HESS telescope array in the direction of the young stellar cluster Westerlund 2 are presented. Methods. Stereoscopic imaging of Cherenkov light emission of $\gamma$-ray induced showers in the atmosp... Read More about Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2.

Search for pulsed VHE gamma-ray emission from young pulsars with HESS (2007)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2007). Search for pulsed VHE gamma-ray emission from young pulsars with HESS. Astronomy & Astrophysics, 466(2), 543-554

Primary particle acceleration above 100 TeV in the shell-type supernovaremnant RX J1713.7-3946 with deep HESS observations (2007)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2007). Primary particle acceleration above 100 TeV in the shell-type supernovaremnant RX J1713.7-3946 with deep HESS observations. Astronomy & Astrophysics, 464(1), 235-243

Constraints on accretion in ultraluminous X-ray sources from Spitzer IRS observations of NGC 4485/4490: Infrared diagnostic diagrams (2007)
Journal Article
Vazquez, G., Hornschemeier, A., Colbert, E., Roberts, T., Ward, M., & Malhotra, S. (2007). Constraints on accretion in ultraluminous X-ray sources from Spitzer IRS observations of NGC 4485/4490: Infrared diagnostic diagrams. Astrophysical Journal Letters, 658(1), L21-L24. https://doi.org/10.1086/513423

Constraining the astrophysical nature of ultraluminous X-ray (ULX) sources, which have X-ray luminosities exceeding 1039 ergs s1, has been elusive due to the optical faintness of any counterparts. With high spectral resolution observations in the ∼10... Read More about Constraints on accretion in ultraluminous X-ray sources from Spitzer IRS observations of NGC 4485/4490: Infrared diagnostic diagrams.

First ground-based measurement of atmospheric Cherenkov light from cosmic rays (2007)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2007). First ground-based measurement of atmospheric Cherenkov light from cosmic rays. Physical Review D, 75(4),

HESS observations of the Galactic Center region and their possible darkmatter interpretation (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). HESS observations of the Galactic Center region and their possible darkmatter interpretation. Physical Review Letters, 97(22),

Fast variability of tera-electron volt gamma rays from the radio galaxy M87 (2006)
Journal Article
Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Beilicke, M., Benbow, W., Berge, D., …Ward, M. (2006). Fast variability of tera-electron volt gamma rays from the radio galaxy M87. Science, 314(5804), 1424-1427. https://doi.org/10.1126/science.1134408

The detection of fast variations of the tera–electron volt (TeV) (1012 eV) -ray flux, on time scales of days, from the nearby radio galaxy M87 is reported. These variations are about 10 times as fast as those observed in any other wave band and imply... Read More about Fast variability of tera-electron volt gamma rays from the radio galaxy M87.

Chandra monitoring observations of the ultraluminous X-ray source NGC 5204 X-1. (2006)
Journal Article
Roberts, T., Kilgard, R., Warwick, R., Goad, M., & Ward, M. (2006). Chandra monitoring observations of the ultraluminous X-ray source NGC 5204 X-1. Monthly Notices of the Royal Astronomical Society, 371(4), 1877-1890. https://doi.org/10.1111/j.1365-2966.2006.10821.x

We report the results of a two-month campaign conducted with the Chandra X-ray observatory to monitor the ultraluminous X-ray source (ULX) NGC 5204 X-1. This was composed of a 50-ks observation, followed by ten 5-ks follow-ups spaced initially at ∼3,... Read More about Chandra monitoring observations of the ultraluminous X-ray source NGC 5204 X-1..