The quasar PKS 1510-089 (z=0.361) was detected with H.E.S.S. with high significance, in data from March and April 2009. The GeV and optical light curves show pronounced variability during the period of H.E.S.S. observations. However, there is insufficient evidence to claim statistically significant variability in the VHE data. Unlike typical VHE-detected blazars where the broadband spectrum is dominated by non-thermal radiation at all wavelengths, the quasar PKS 1510-089 has a bright thermal component in the optical to UV frequency band. The paper can be found on the preprint server: arXiv:1304.8071.

The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 (z=0.095) at high and very high-energy with the Fermi Large Area Telescope (LAT) and the High Energy Stereoscopic System (H.E.S.S.) is reported. The broadband spectral energy distribution is modelled with a one-zone synchrotron self-Compton (SSC) model. The paper can be found on the preprint server: arXiv:1304.4023.

The time-lapse movies by Mathieu de Naurois show the H.E.S.S. telescope under the Namibian night sky, with the Milky Way visible in the 2nd movie (movie 1, movie 2).

Very high-energy gamma-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 to GeV range. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. The paper can be found on the preprint server: arXiv:1303.1628.

The gamma-ray binary system PSR B1259-63/LS 2883 was observed around its 15 Dec. 2010 periastron passage, and gamma ray emission was detected with high significance. The measured integral flux and the spectral shape of the 2011 data are compatible with the results obtained around previous periastron passages. Comparison with Fermi-LAT measurements around periastron indicate that mechanisms of GeV and TeV emission are different. The paper can be found on the preprint server: arXiv:1301.3930.

Globular clusters (GCs) are established emitters of high-energy gamma-rays which could originate from the cumulative emission of the numerous millisecond pulsars; very high energy (VHE) gamma rays were detected from the direction of Terzan 5. This work describes a search for VHE gamma rays from 15 globular clusters covered by H.E.S.S. observations, and uses a stacking analysis to provide a stringent flux limit on this set of objects. The paper can be found on the preprint server: arXiv:1301.1678.

Gamma-ray line signatures can be expected in the very-high-energy domain due to self-annihilation or decay of dark matter particles in space. Using H.E.S.S. data, upper limits on line-like emission are obtained in the energy range between ~500 GeV and ~25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. The paper can be found on the preprint server: arXiv:1301.1173. See also APS Physics Spotlight.

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 gamma-rays on the spectra of the brightest extragalactic H.E.S.S. sources. Analysis of a total of ~10^5 gamma-ray events enables the detection of an EBL signature at the 8.8 std dev level and constitutes the first measurement of the EBL optical depth using very-high energy (E>100 GeV) gamma-rays. The paper can be found on the preprint server: arXiv:1212.3409.

The previously unidentified very high-energy gamma-ray source HESS J1303-631, discovered in 2004, is re-examined including new data from the H.E.S.S. Cherenkov telescope array. Significant energy-dependent morphology of the gamma-ray source is detected with high-energy emission positionally coincident with the pulsar PSR J1301-6305 and lower energy emission extending to the South-East of the pulsar. The PWN is also detected in X-rays, extending 2-3' from the pulsar position towards the center of the gamma-ray emission region. The paper can be found on the preprint server: arXiv:1210.6513.

Web galeries with pictures from the inauguration, from the open day and more telescope images are now online. See also the telescopes 'dancing' (80 MB version, 8 MB version) . Images by Christian Föhr, MPIK.

Vela X is a region of extended radio emission in the western part of the Vela constellation: one of the nearest pulsar wind nebulae, associated with the energetic Vela pulsar (PSR B0833-45). Extended very-high-energy gamma-ray emission was discovered using the H.E.S.S. experiment in 2004. New data are reported, probing the entire Vela X nebula region, including larger offsets from the radio 'cocoon'. The paper can be found on the preprint server: arXiv:1210.1359.

Following a workshop on Heja Lodge near Windhoek, the H.E.S.S. II telescope was inaugurated on Sept. 28, 2012; keynote speaker was the Hon. Minister of Education, Dr. Abraham Iyambo.

Many hundred visitors came to the Open Day on Sept. 30, 2012 to see the giant new H.E.S.S. II telescope.

September 2012 marks the 10th anniversary of the inaugration of the first H.E.S.S. telescope. See the highlights in H.E.S.S. history, the H.E.S.S. Hall of Fame for the most highly-cited H.E.S.S. publications, and the H.E.S.S. Sky featured in the September 2012 Source of the Month column.

The first extragalactic pulsar wind nebula (PWN) detected in gamma rays is reported: N157B, located in the large Magellanic Cloud (LMC). The detection of a PWN at such a large distance is possible due to the pulsar's favourable spin-down luminosity and a bright infrared photon-field serving as an inverse-Compton-scattering target for accelerated leptons. A leptonic multi-wavelength model shows that an energy of about 4 x 10⁴⁹ erg is stored in electrons and positrons in the Nebula, which implies that the pulsar's birth period was shorter than 10 ms. The paper can be found on the preprint server: arXiv:1208.1636.

In some galaxy clusters powerful AGN have blown bubbles with cluster scale extent into the ambient medium. The main pressure support of these bubbles is not known to date, but cosmic rays are a viable scenario, implying copious gamma-ray emission. Hydra A, the closest galaxy cluster hosting a cluster scale AGN outburst, located at a redshift of 0.0538, is investigated for being a gamma-ray emitter with H.E.S.S. and the Fermi Large Area Telescope (Fermi-LAT). No signal has been found in in 20.2 hours of H.E.S.S. observations and 38 months of Fermi-LAT data. Upper limits on the gamma-ray flux are derived and are compared to models. The non-detection of Hydra A in gamma-rays has important implications on the particle populations and physical conditions inside the bubbles in this system. The paper can be found on the preprint server: arXiv:1208.1370.

After concluding the mirror alignment campaign, the new huge H.E.S.S. II telescope with its 600 m² mirror saw its first light at 0:43 a.m. on 26 July 2012, detecting its very first images of atmospheric particle cascades generated by cosmic gamma rays and by cosmic rays, and marking the next big step in exploring the Southern sky at gamma-ray energies. The images illustrate the dramatically improved intensity and resolution with which H.E.S.S. II views the particle cascades. See press release.

Very high energy (H.E.S.S.) and high energy (Fermi) data are analysed in order to investigate the non-thermal processes in the starburst galaxy NGC 253. No evidence for a spectral break or turnover is found over the dynamic range of both instruments. The smooth alignment between the spectra in the VHE and HE energy range suggests that the same transport processes dominate in the entire energy region; in a hadronic scenario, the measured gamma ray index of about 2.3 then corresponds to the spectrum produced by the ensemble of sources at the core of NGC 253. The paper can be found on the preprint server: arXiv:1205.5485.

The BL Lac object PKS 1440-389, located at a tentative redshift of z=0.065, has been reported as a hard, bright, and steady extragalactic source at GeV energies in the Fermi-LAT catalogue. The extrapolation of the Fermi-LAT spectrum to very high energies, together with its brightness in the radio and X-ray bands, makes this BL Lac object a good candidate for VHE emission. PKS 1440-389 was observed with H.E.S.S. for ~6h in the past two months, resulting in a signal exceeding 5 standard deviation in the preliminary onsite analysis. The flux is estimated to be ~3% of the flux of the Crab Nebula above 200 GeV. No significant variability has been detected in the H.E.S.S. data. The discovery was announced as ATel #4072.

The massive binary system Eta Carinae and the surrounding HII complex, the Carina Nebula, are potential particle acceleration sites from which very-high-energy gamma-ray emission could be expected. This paper presents data collected with the H.E.S.S. telescope array from 2004 to 2010, which cover a full orbit of Eta Carinae. In the 33-hour data set no hint of significant gamma-ray emission from Eta Carinae has been found and an upper limit on the gamma-ray flux is derived which, together with the detection of high-energy gamma-ray emission by Fermi-LAT up to 100 GeV, implies a cut-off in the gamma-ray spectrum between 100 and 500 GeV gamma ray energy. The paper is in press in MNRAS and can be found on the preprint server: arXiv:1204.5690.

1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus belonging to the class of bright BL Lac objects. We report on results from observations performed between 2006-2010 with H.E.S.S. VHE emission at a position coincident with 1RXS J101015.9-311909 is detected with H.E.S.S. for the first time. In a total data set of about 49 h, we measure 263 excess counts, corresponding to a significance of 7.1 sigma. Also reported is the analysis of contemporaneous ATOM, Swift and Fermi/LAT data. The paper is in press in A&A and can be found on the preprint server: arXiv:1204.1964.

The observational coverage with HESS of the Carina region in VHE gamma-rays benefits from deep exposure of the neighboring open cluster Westerlund 2. The observations have revealed a new extended region of VHE gamma-ray emission. The source HESS J1018-589 shows a bright, point-like emission region positionally coincident with the supernova remnant G284.3-1.8 and the Fermi source 1FGL J1018.6 - 5856, and a diffuse extension towards the direction of the pulsar PSR J1016-5857. The paper is in press in A&A and can be found on the preprint server: arXiv:1203.3215.

Due to their potentially large boost factors enhancing the annihilation rate of hypothetical dark matter particles, galaxy clusters are an interesting target to search for annihilation signatures. The H.E.S.S. data on the Fornax cluster are used to derive limits on the annihilation cross section for different dark matter models, such as supersymmetric or Kaluza-Klein models. The paper is in press in ApJ and can be found on the preprint server: arXiv:1202.5494 .

Multiwavelength observations of the blazar PKS 2155-304 during two weeks in July and August 2006, the period when two exceptional flares at very high energies occurred, provide a detailed picture of the evolution of its emission. The complete data set from this campaign is presented, including observations in VHE gamma-rays (H.E.S.S.), X-rays (RXTE, CHANDRA, SWIFT XRT), optical (SWIFT UVOT, Bronberg, Watcher, ROTSE), and in the radio band (NRT, HartRAO, ATCA). Optical and radio light curves from 2004 to 2008 are compared to the available VHE data from this period, to put the 2006 campaign into the context of the long-term evolution of the source. The paper is in press in A&A and can be found on the preprint server: arXiv:1201.4135 .

The blazar 1ES 0414+009 (at redshift z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high energy (VHE) gamma-rays due to its high X-ray and radio flux. In observations made between October 2005 and December 2009 with H.E.S.S., 1ES 0414+009 is detected for the first time in the VHE band. An excess of 224 events is measured, corresponding to a significance of 7.8 sigma. In the Fermi (GeV) energy range, the source exhibits a rather hard spectrum, which continues into the H.E.S.S. (TeV) range once corrected for absorption by the extragalactic background light. The paper is in press in A&A and can be found on the preprint server: arXiv:1201.2044 .