Search Publications
GOODS-Herschel: evidence of a UV extinction bump in galaxies at z > 1
Magnelli, B.; Altieri, B.; Aussel, H. +16 more
Context. Dust attenuation curves in external galaxies are useful for studying their dust properties as well as interpreting their intrinsic spectral energy distributions. These functions are not very well known in the UV range whether at low or high redshift. In particular, the presence or absence of a UV bump at 2175 Å remains an open issue that …
Seasonal changes in Titan's meteorology
West, R. A.; Schaller, E. L.; McEwen, A. S. +5 more
The Cassini Imaging Science Subsystem has observed Titan for ∼1/4 Titan year, and we report here the first evidence of seasonal shifts in preferred locations of tropospheric methane clouds. South-polar convective cloud activity, common in late southern summer, has become rare. North-polar and northern mid-latitude clouds appeared during the approa…
A Low Escape Fraction of Ionizing Photons of L > L* Lyman Break Galaxies at z = 3.3
Fiore, F.; Castellano, M.; Pentericci, L. +12 more
We present an upper limit for the relative escape fraction (f rel esc) of ionizing radiation at z ~ 3.3 using a sample of 11 Lyman break galaxies (LBGs) with deep imaging in the U band obtained with the Large Binocular Camera, mounted on the prime focus of the Large Binocular Telescope. We selected 11 LBGs with secure redshif…
Iron line profiles in Suzaku spectra of bare Seyfert galaxies
Porquet, D.; Reeves, J. N.; Terashima, Y. +3 more
We methodically model the broad-band Suzaku spectra of a small sample of six 'bare' Seyfert galaxies: Ark 120, Fairall 9, MCG -02-14-009, Mrk 335, NGC 7469 and SWIFT J2127.4+5654. The analysis of bare Seyferts allows a consistent and physical modelling of active galactic nuclei due to a weak amount of any intrinsic warm absorption, removing the de…
Electron Temperature Gradient Scale at Collisionless Shocks
Krasnoselskikh, Vladimir; Schwartz, Steven J.; Henley, Edmund +1 more
Shock waves are ubiquitous in space and astrophysics. They transform directed flow energy into thermal energy and accelerate energetic particles. The energy repartition is a multiscale process related to the spatial and temporal structure of the electromagnetic fields within the shock layer. While large scale features of ion heating are known, the…
A tool for empirical forecasting of major flares, coronal mass ejections, and solar particle events from a proxy of active-region free magnetic energy
Falconer, David; Barghouty, Abdulnasser F.; Khazanov, Igor +1 more
This paper describes a new forecasting tool developed for and currently being tested by NASA's Space Radiation Analysis Group (SRAG) at Johnson Space Center, which is responsible for the monitoring and forecasting of radiation exposure levels of astronauts. The new software tool is designed for the empirical forecasting of M- and X-class flares, c…
Hapke modeling of Rhea surface properties through Cassini-VIMS spectra
Brown, R. H.; Buratti, B. J.; Clark, R. N. +8 more
The surface properties of the icy bodies in the saturnian system have been investigated by means of the Cassini-VIMS (Visual Infrared Mapping Spectrometer) hyperspectral imager which operates in the 0.35-5.1 µm wavelength range. In particular, we have analyzed 111 full disk hyperspectral images of Rhea ranging in solar phase between 0.08° an…
Homologous Flares and Magnetic Field Topology in Active Region NOAA 10501 on 20 November 2003
Mandrini, C. H.; Schmieder, B.; Démoulin, P. +4 more
We present and interpret observations of two morphologically homologous flares that occurred in active region (AR) NOAA 10501 on 20 November 2003. Both flares displayed four homologous Hα ribbons and were both accompanied by coronal mass ejections (CMEs). The central flare ribbons were located at the site of an emerging bipole in the centre of the…
Chromospheric Jet and Growing "Loop" Observed by Hinode: New Evidence of Fan-spine Magnetic Topology Resulting from Flux Emergence
Liu, Wei; Berger, Thomas E.; Tarbell, Theodore D. +2 more
We present observations of a chromospheric jet and growing "loop" system that show new evidence of a fan-spine topology resulting from magnetic flux emergence. This event, occurring in an equatorial coronal hole on 2007 February 9, was observed by the Hinode Solar Optical Telescope in the Ca II H line in unprecedented detail. The predecessor of th…
Hubble Space Telescope Observations of the Double-peaked Emission Lines in the Seyfert Galaxy Markarian 78: Mass Outflows from a Single Active Galactic Nucleus
Kraemer, S. B.; Crenshaw, D. M.; Schmitt, H. R. +3 more
Previous ground-based observations of the Seyfert 2 galaxy Mrk 78 revealed a double set of emission lines, similar to those seen in several active galactic nuclei (AGNs) from recent surveys. Are the double lines due to two AGNs with different radial velocities in the same galaxy, or are they due to mass outflows from a single AGN? We present a stu…