X-Ray and Gamma-Ray Observations
Instruments
We use gamma-ray data from the Whipple/VERITAS Cerenkov telescope and X-ray data from the RXTE, Chandra, and XMM-Newton satellites to explore the astrophysics of supermassive black holes and to learn about structure formation in the universe.
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| Chandra | VERITAS | XMM-Newton | RXTE |
Blazars
According to the present paradigm, almost every galaxy harbors a massive black hole at its center. These black holes have masses of between several million and several billion solar masses. In the case of so-called Active Galactic Nuclei (AGN), accretion of interstellar matter onto the black hole gives rise to extremely powerful, double sided collimated plasma outflows, so-called jets. In the case of a special class of (AGN), in so-called blazars one of the two jets is directly aimed at the observer. The jet plasma moves extremely fast, with a speed very close to the speed of light. So-called relativistic Doppler boosting amplifies the brightness from these sources by a factor of 10,000, making them some of the brightest sources in the universe. We organize multiwavelength campaigns of blazars with observations in the radio, infrared, optical, X-ray and gamma-ray bands. The main scientific drivers for such broadband observations are: (i) the study of the matter, energy content, and structure of jets from supermassive black holes, (ii) the time resolved investigation of particle acceleration processes, (iii) the research on the connection between the accreting supermassive black hole system and the jet parameters, and (iv) the measurement of the total infrared/optical luminosity of the universe.
Radio Galaxies
Radio galaxies are AGN with very large jets; diameters on the order of 1 million light years are common. The Chandra satellite has shown that these jets emit not only radio, but also X-ray emission. Using data from the satellite borne X-ray telescopes Chandra and XMM Newton, we investigate two questions: (i) what are jets made of? (ii) how do the jets impact galaxy and star formation by heating interstellar gas.
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| Chandra Image of the Radio Galaxy 3C390.3 |
Gamma-Ray Bursts
Gamma-Ray Bursts most probably originate from extremely potent Supernova Explosions, so-called Hypernova. Study of these objects reveals key-properties about structure formation in the early universe, as well as about the exciting relativistic astrophysics of the powerful explosion.
Galaxy Cluster
Galaxy clusters are the most massive virialized objects in the universe. Their formation is an slow process, still ongoing in the local universe. We use the Chandra and XMM Newton telescopes to study the X-ray emission from the hot gas (ICM for Intracluster Medium) that makes up most of the luminous mass of galaxy clusters. Our focus is on studying the interaction of radio galaxies and the ICM, elucidating the role of supermassive black holes on the galaxy and star formation in galaxy clusters.
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| Chandra Image of the Galaxy Cluster 3C129 |