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A long XMM-Newton observation of an extreme narrow-line Seyfert 1: PG 1244+026 (2013)
Journal Article
Jin, C., Done, C., Middleton, M., & Ward, M. (2013). A long XMM-Newton observation of an extreme narrow-line Seyfert 1: PG 1244+026. Monthly Notices of the Royal Astronomical Society, 436(4), 3173-3185. https://doi.org/10.1093/mnras/stt1801

We explore the origin of the strong soft X-ray excess in narrow-line Seyfert 1 galaxies using spectral-timing information from a 120 ks XMM–Newton observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true additional soft X-... Read More about A long XMM-Newton observation of an extreme narrow-line Seyfert 1: PG 1244+026.

Discovery of very high energy γ-ray emission from the BL Lacertae object PKS 0301−243 with H.E.S.S (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Ait Benkhali, F., Akhperjanian, A., Angüner, E., …Zechlin, H. (2013). Discovery of very high energy γ-ray emission from the BL Lacertae object PKS 0301−243 with H.E.S.S. Astronomy & Astrophysics, 559, Article A136. https://doi.org/10.1051/0004-6361/201321639

The active galactic nucleus PKS 0301−243 (z = 0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV <E < 100 GeV) by Fermi/LAT. This paper reports on the discovery of PKS 0301−243 at very high energies (E >... Read More about Discovery of very high energy γ-ray emission from the BL Lacertae object PKS 0301−243 with H.E.S.S.

Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155-304 energy spectrum (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Ait Benkhali, F., Akhperjanian, A., Angüner, E., …Collaboration, H. (2013). Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155-304 energy spectrum. Physical Review D, 88(10), Article 102003. https://doi.org/10.1103/physrevd.88.102003

Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model of particle physics. In astrophysical environments comprising high-energy gamma rays and turbulent magnetic fields, the existence of... Read More about Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155-304 energy spectrum.

HESS and Fermi-LAT discovery of γ-rays from the blazar 1ES 1312−423 (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Angüner, E., Anton, G., …Kadler, M. (2013). HESS and Fermi-LAT discovery of γ-rays from the blazar 1ES 1312−423. Monthly Notices of the Royal Astronomical Society, 434(3), 1889-1901. https://doi.org/10.1093/mnras/stt1081

A deep observation campaign carried out by the High Energy Stereoscopic System (HESS) on Centaurus A enabled the discovery of γ-rays from the blazar 1ES 1312−423, 2° away from the radio galaxy. With a differential flux at 1 TeV of ϕ(1 TeV) = (1.9 ± 0... Read More about HESS and Fermi-LAT discovery of γ-rays from the blazar 1ES 1312−423.

A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies (2013)
Journal Article
Done, C., Jin, C., Middleton, M., & Ward, M. (2013). A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies. Monthly Notices of the Royal Astronomical Society, 434(3), 1955-1963. https://doi.org/10.1093/mnras/stt1138

We show that disc continuum fitting can be used to constrain black hole spin in a subclass of narrow-line Seyfert 1 (NLS1) active galactic nuclei as their low mass and high mass accretion rate means that the disc peaks at energies just below the soft... Read More about A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies.

H.E.S.S. discovery of VHE γ-rays from the quasar PKS 1510−089 (2013)
Journal Article
H.E.S.S. Collaboration Abramowski, A. A., F. Aharonian, F. A., A.G. Anton, G. B., S. Balzer, A. B., A. Becherini, Y. B. T., J. Behera, B. B., …S., H. (2013). H.E.S.S. discovery of VHE γ-rays from the quasar PKS 1510−089. Astronomy & Astrophysics, 554, Article A107. https://doi.org/10.1051/0004-6361/201321135

The quasar PKS 1510−089 (z = 0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E ≥ 0.1 TeV) emission. VHE γ-rays we... Read More about H.E.S.S. discovery of VHE γ-rays from the quasar PKS 1510−089.

Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9-185406 (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Angüner, E., Anton, G., …Zechlin, H. (2013). Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9-185406. Astronomy & Astrophysics, 554, Article A72. https://doi.org/10.1051/0004-6361/201220996

The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9–185406 (z = 0.095) at high (HE; 100 MeV < E < 300 GeV) and very high-energy (VHE; E > 100 GeV) with the Fermi Large Area Telescope (LAT) and the High Energy Stereoscopic Sy... Read More about Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9-185406.

A near-infrared relationship for estimating black hole masses in active galactic nuclei (2013)
Journal Article
Landt, H., Ward, M., Peterson, B., Bentz, M., Elvis, M., Korista, K., & Karovska, M. (2013). A near-infrared relationship for estimating black hole masses in active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 432(1), 113-126. https://doi.org/10.1093/mnras/stt421

Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra using scaling relations anchored in reverberation mapping results. In particular, the two quantities needed for calculating black... Read More about A near-infrared relationship for estimating black hole masses in active galactic nuclei.

Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift (2013)
Journal Article
Collaboration, H., Abramowski, A., Acero, F., Akhperjanian, A., Anton, G., Balenderan, S., …Pelat, D. (2013). Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift. Astronomy & Astrophysics, 552, Article A118. https://doi.org/10.1051/0004-6361/201321108

Very high-energy γ-ray emission from PKS 0447−439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV... Read More about Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift.

H.E.S.S. observations of the binary system PSR B1259-63/LS 2883 around the 2010/2011 periastron passage (2013)
Journal Article
Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., Balenderan, S., …Zechlin, H. (2013). H.E.S.S. observations of the binary system PSR B1259-63/LS 2883 around the 2010/2011 periastron passage. Astronomy & Astrophysics, 551, Article A94. https://doi.org/10.1051/0004-6361/201220612

Aims. We present very high energy (VHE; E > 100 GeV) data from the γ-ray binary system PSR B1259-63/LS 2883 taken around its periastron passage on 15th of December 2010 with the High Energy Stereoscopic System (H.E.S.S.) of Cherenkov Telescopes. We a... Read More about H.E.S.S. observations of the binary system PSR B1259-63/LS 2883 around the 2010/2011 periastron passage.

Search for very-high-energy γ-ray emission from Galactic globular clusters 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 very-high-energy γ-ray emission from Galactic globular clusters with H.E.S.S. Astronomy & Astrophysics, 551, Article A26. https://doi.org/10.1051/0004-6361/201220719

Context. Globular clusters (GCs) are established emitters of high-energy (HE, 100 MeV < E < 100 GeV) γ-ray radiation which could originate from the cumulative emission of the numerous millisecond pulsars (msPSRs) in the clusters’ cores or from invers... Read More about Search for very-high-energy γ-ray emission from Galactic globular clusters with H.E.S.S.

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.

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.