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A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties
Done, Chris; Ward, Martin; Jin, Chichuan
In this third paper in a series of three, we present a detailed study of the broad-band spectral energy distribution (SED) of active galactic nuclei (AGNs) based on a nearby unobscured type 1 AGN sample. We perform a systematic cross-correlation study of several key parameters, i.e. Γ2-10 keV, L2-10 keV, Lbol/L
On the probability of occurrence of extreme space weather events
Riley, Pete
By virtue of their rarity, extreme space weather events, such as the Carrington event of 1859, are difficult to study, their rates of occurrence are difficult to estimate, and prediction of a specific future event is virtually impossible. Additionally, events may be extreme relative to one parameter but normal relative to others. In this study, we…
Temperature-pressure profile of the hot Jupiter HD 189733b from HST sodium observations: detection of upper atmospheric heating
Pont, F.; Lecavelier des Etangs, A.; Vidal-Madjar, A. +4 more
We present transmission spectra of the hot Jupiter HD 189733b taken with the Space Telescope Imaging Spectrograph (STIS) aboard Hubble Space Telescope (HST). The spectra cover the wavelength range 5808-6380 Å with a resolving power of R= 5000. We detect absorption from the Na I doublet within the exoplanet's atmosphere at the 9σ confidence level w…
The Initial Mass Function of the Orion Nebula Cluster across the H-burning Limit
Henning, T.; Robberto, M.; Da Rio, N. +2 more
We present a new census of the Orion Nebula Cluster over a large field of view (gsim 30' × 30'), significantly increasing the known population of stellar and substellar cluster members with precisely determined properties. We develop and exploit a technique to determine stellar effective temperatures from optical colors, nearly doubling the previo…
Chandra/HETGS Observations of the Brightest Flare Seen from Sgr A*
Miller, J. M.; Nowak, M. A.; Grosso, N. +10 more
Starting in 2012, we began an unprecedented observational program focused on the supermassive black hole in the center of our Galaxy, Sgr A*, utilizing the High Energy Transmission Grating Spectrometer (HETGS) instrument on the Chandra X-Ray Observatory. These observations will allow us to measure the quiescent X-ray spectra of Sgr A* for the firs…
Response of the Photospheric Magnetic Field to the X2.2 Flare on 2011 February 15
Liu, Yang; Liu, Chang; Wang, Haimin +3 more
It is well known that the long-term evolution of the photospheric magnetic field plays an important role in building up free energy to power solar eruptions. Observations, despite being controversial, have also revealed a rapid and permanent variation of the photospheric magnetic field in response to the coronal magnetic field restructuring during…
Hint of a transiting extended atmosphere on 55 Cancri b
Moutou, C.; Bonfils, X.; Ehrenreich, D. +9 more
The naked-eye star
Planetary surface dating from crater size-frequency distribution measurements: Spatial randomness and clustering
Platz, T.; Michael, G. G.; Kneissl, T. +1 more
We describe a quantitative procedure to measure the degree of clustering in an observed crater population relative to a series of randomly distributed populations. We split the population by according to crater size to be able to identify clustering at different scales, and find that a clustering analysis based on the mean 2nd-closest neighbour di…
Spectral Energy Distributions of Local Luminous and Ultraluminous Infrared Galaxies
Sanders, D. B.; Frayer, D. T.; Kartaltepe, J. S. +19 more
Luminous (LIRGs; log (L IR/L ⊙) = 11.00-11.99) and ultraluminous infrared galaxies (ULIRGs; log (L IR/L ⊙) = 12.00-12.99) are the most extreme star-forming galaxies in the universe. The local (U)LIRGs provide a unique opportunity to study their multi-wavelength properties in detail for comparison with th…
Deep Near-infrared Spectroscopy of Passively Evolving Galaxies at z >~ 1.4
Cimatti, A.; Daddi, E.; Sanders, D. B. +21 more
We present the results of new near-IR spectroscopic observations of passive galaxies at z >~ 1.4 in a concentration of BzK-selected galaxies in the COSMOS field. The observations have been conducted with Subaru/MOIRCS, and have resulted in absorption lines and/or continuum detection for 18 out of 34 objects. This allows us to measure spectrosco…