Search Publications
Statistical evidence for O+ energization and outflow caused by wave-particle interaction in the high altitude cusp and mantle
Waara, M.; Nilsson, H.; Slapak, R. +3 more
We present a statistical study of the low (<1 Hz) frequency electric and magnetic field spectral densities observed by Cluster spacecraft in the high altitude cusp and mantle region. At the O+ gyrofrequency (0.02-0.5 Hz) for this region the electric field spectral density is on average 0.2-2.2 (mV m-1)2 Hz-…
A Panchromatic View of NGC 602: Time-resolved Star Formation with the Hubble and Spitzer Space Telescopes
Smith, Linda J.; Cignoni, M.; Gallagher, J. S., III +16 more
We present the photometric catalogs for the star-forming cluster NGC 602 in the wing of the Small Magellanic Cloud covering a range of wavelengths from optical (HST/ACS F555W, F814W, and SMARTS/ANDICAM V, I) to infrared (Spitzer/IRAC 3.6, 4.5, 5.8, and 8 µm and MIPS 24 µm). Combining this with Infrared Survey Facility near-infrared pho…
Black hole accretion rings revealed by future X-ray spectroscopy
Dovčiak, M.; Karas, V.; Svoboda, J. +1 more
Spectral features can arise by reflection of coronal X-rays on a black hole accretion disc. The resulting profile bears various imprints of a strong gravitational field acting on the light-emitting gas. The observed shape of the reflection line is formed by integrating contributions over a range of radii across the accretion disc plane, where the …
Coronal Dimmings and the Early Phase of a CME Observed with STEREO and Hinode/EIS
Möstl, C.; Temmer, M.; Veronig, A. M. +2 more
We investigate the early phase of the 13 February 2009 coronal mass ejection (CME). Observations with the twin STEREO spacecraft in quadrature allow us to compare for the first time in one and the same event the temporal evolution of coronal EUV dimmings, observed simultaneously on-disk and above-the-limb. We find that these dimmings are synchroni…
Compton-thick active galactic nuclei inside local ultraluminous infrared galaxies
Nardini, E.; Risaliti, G.
We present an X-ray analysis of the most luminous obscured active galactic nuclei (AGN) inside local ultraluminous infrared galaxies (ULIRGs). Our sample consists of 10 sources, harbouring AGN components with estimated luminosity in excess of ∼1012 L⊙ and yet unidentified at optical wavelengths because of their large obscurat…
Thermal X-Ray Emission from the Shocked Stellar Wind of Pulsar Gamma-Ray Binaries
Paredes, J. M.; Zabalza, V.; Bosch-Ramon, V.
Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from th…
Quiet-Sun imaging asymmetries in Na I D1 compared with other strong Fraunhofer lines
Leenaarts, J.; Carlsson, M.; Rouppe van der Voort, L. H. M. +3 more
Imaging spectroscopy of the solar atmosphere using the Na I D1 line yields marked asymmetry between the blue and red line wings: sampling a quiet-Sun area in the blue wing displays reversed granulation, whereas sampling in the red wing displays normal granulation. The Mg I b2 line of comparable strength does not show this asy…
X-ray observations of PKS 0745-191 at the virial radius: are we there yet?
Rossetti, M.; Molendi, S.; Gastaldello, F. +1 more
Aims: We reassess the properties of the ICM at large radii in the galaxy cluster PKS 0745-191 in light of recent Suzaku measurements.
Methods: We analyze an archival 10.5 ks ROSAT/PSPC observation to extract the surface-brightness profile of PKS 0745-191 and infer the deprojected density profile. We then compare the ROSAT surface-brightn…
Multiwavelength Spectroscopy of PSR B0656+14
Pavlov, George G.; Kargaltsev, Oleg; Durant, Martin
Using high-quality Hubble Space Telescope observations, we construct the near-infrared (NIR) to far-ultraviolet (FUV) spectral energy distribution (SED) of PSR B0656+14. The SED is non-monotonic. Fitting it with a simple combination of a Rayleigh-Jeans spectrum (UV) and non-thermal power law (PL; optical/NIR) leaves significant residuals, strongly…
Comparing spectral models for ultraluminous X-ray sources with NGC 4517 ULX1
Done, C.; Fabian, A. C.; Roberts, T. P. +4 more
We present the previously unanalysed high-quality XMM-Newton spectrum of an ultraluminous X-ray source (ULX) candidate in NGC 4517. As with other high-quality ULX spectra, a downturn in the spectrum is observed at ∼6 keV. Both of the recent disc reflection and Comptonization interpretations of this feature are applied, in order to present a direct…