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A broad-band spectral analysis of eight radio-loud type 1 active galactic nuclei selected in the hard X-ray band
de Rosa, A.; Bird, A. J.; Fiocchi, M. +6 more
Starting from a complete sample of type 1 active galactic nuclei (AGN) observed by INTEGRAL in the 20-40 keV band, we have selected a set of eight AGN which can be classified as radio-loud objects according to their 1.4 GHz power density, radio-to-hard X-ray flux density ratio and radio morphology. The sample contains six broad-line radio Galaxies…
Analysis of MDI High-Degree Mode Frequencies and their Rotational Splittings
Schou, J.; Korzennik, S. G.; Rabello-Soares, M. C.
We present a detailed analysis of solar acoustic mode frequencies and their rotational splittings for modes with degree up to 900. They were obtained by applying spherical harmonic decomposition to full-disk solar images observed by the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory spacecraft. Global helioseismology analy…
Photoemission Phenomena in the Solar System
Strobel, D. F.; Crovisier, J.; Cravens, T. E. +2 more
Much of what we know about the atmospheres of the planets and other bodies in the solar system comes from detection of photons over a wide wavelength range, from X-rays to radio waves. In this chapter, we present current information in various categories—measurements of the airglows of the terrestrial planets, the dayglows of the outer planets and…
An Upper Mass Limit on a Red Supergiant Progenitor for the Type II-Plateau Supernova SN 2006my
Leonard, Douglas C.; Kraus, Adam L.; Gal-Yam, Avishay +5 more
We analyze two pre-supernova (SN) and three post-SN high-resolution images of the site of the Type II-Plateau supernova SN 2006my in an effort to either detect the progenitor star or to constrain its properties. Following image registration, we find that an isolated stellar object is not detected at the location of SN 2006my in either of the two p…
Limits on the X-ray and optical luminosity of the progenitor of the Type Ia supernova 2007sr
Bassa, Cees; Nelemans, Gijs; Voss, Rasmus +1 more
We present Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 (WFPC2), Galaxy Evolution Explorer (GALEX) and Chandra observations of the position of the Type Ia supernova 2007sr in the Antennae galaxy, taken before the explosion. No source is found in any of the observations, allowing us to put interesting constraints on the progenitor lum…
The Signature of Evolving Turbulence in Quiet Solar Wind as Seen by Ulysses
Chapman, S. C.; Nicol, R. M.; Dendy, R. O.
Solar wind fluctuations, such as magnetic field or velocity, show power-law power spectra suggestive both of an inertial range of intermittent turbulence (with ~-5/3 exponent), and at lower frequencies, of fluctuations of coronal origin (with ~-1 exponent). The Ulysses spacecraft spent many months in the quiet fast solar wind above the Sun's polar…
[OIII] emitters in the field of the MRC0316-257 protocluster
Pentericci, L.; Rosati, P.; Stanford, S. A. +12 more
Venemans et al. found evidence for an overdensity of Lyα emission-line galaxies associated with the radio galaxy MRC0316-257 at z = 3.13 indicating the presence of a massive protocluster. Here, we present the results of a search for additional star-forming galaxies and active galactic nucleus (AGN) within the protocluster. Narrow-band infrared ima…
Albedo models for the residual south polar cap on Mars: Implications for the stability of the cap under near-perihelion global dust storm conditions
Bjorkman, Jon E.; James, Philip B.; Bonev, Boncho P. +2 more
It is uncertain whether the residual (perennial) south polar cap on Mars is a transitory or a permanent feature in the current Martian climate. While there is no firm evidence for complete disappearance of the cap in the past, clearly observable changes have been documented. Observations suggest that the perennial cap lost more CO 2 mat…
Least-squares multi-spacecraft gradient calculation with automatic error estimation
de Keyser, J.
Multi-spacecraft missions allow the gradient of important physical quantities in the terrestrial environment to be determined. The gradient can be computed from four simultaneous measurements in a straightforward way, but this computation does not produce proper error estimates, making it hard to assess the meaningfulness of the result. Recently d…
Observational Biases Masquerading as Cosmological Effects? a Cautionary tale about Blue Tilts and Other Trends in Globular Cluster Systems
Kundu, Arunav
The high spatial resolution of the Hubble Space Telescope (HST) has led to tremendous progress in many areas of astronomy. The ability of the HST to peer into the bright inner regions of galaxies and distinguish between globular clusters (GCs) and background objects has been particularly beneficial to the study of clusters. However, the very virtu…