Search Publications
EMIC triggered chorus emissions in Cluster data
Pickett, J. S.; SantolíK, O.; Cornilleau-Wehrlin, N. +6 more
Electromagnetic ion cyclotron (EMIC) triggered chorus emissions have recently been a subject of several experimental, theoretical and simulation case studies, noting their similarities with whistler-mode chorus. We perform a survey of 8 years of Cluster data in order to increase the database of EMIC triggered emissions. The results of this is that…
Solar Magnetic Tracking. IV. The Death of Magnetic Features
Lamb, D. A.; DeForest, C. E.; Parnell, C. E. +2 more
The removal of magnetic flux from the quiet-Sun photosphere is important for maintaining the statistical steady state of the magnetic field there, for determining the magnetic flux budget of the Sun, and for estimating the rate of energy injected into the upper solar atmosphere. Magnetic feature death is a measurable proxy for the removal of detec…
Kinematics of the Intermediate-mass Black Hole Candidate HLX-1
Soria, Roberto; Hau, George K. T.; Pakull, Manfred W.
We studied the optical spectrum of HLX-1 during its latest outburst, using the FORS2 spectrograph on the Very Large Telescope. We detect an Hα emission line centered at λ = 6718.9 ± 0.9 Å and find that its projected radial velocity with respect to the nucleus of ESO 243-49 is 424 ± 27 km s-1, while the maximum rotational velocity of the…
Giant Lobes of Centaurus A Radio Galaxy Observed with the Suzaku X-Ray Satellite
Simionescu, A.; Cheung, C. C.; Fukazawa, Y. +15 more
We report on Suzaku observations of selected regions within the southern giant lobe of the radio galaxy Centaurus A. In our analysis we focus on distinct X-ray features detected with the X-ray Imaging Spectrometer within the range 0.5-10 keV, some of which are likely associated with fine structure of the lobe revealed by recent high-quality radio …
The ACS LCID Project - VIII. The short-period Cepheids of Leo A
Skillman, Evan D.; Cole, Andrew A.; Tolstoy, Eline +9 more
We present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Space Telescope. We detected 166 bona fide variables in our field, of which about 60 per cent are new discoveries and 33 candidate variables. Of the confirmed variables, w…
Azimuthal directions of equatorial noise propagation determined using 10 years of data from the Cluster spacecraft
Pickett, J. S.; Santolík, O.; Němec, F. +2 more
Equatorial noise (EN) emissions are electromagnetic waves at frequencies between the proton cyclotron frequency and the lower hybrid frequency routinely observed within a few degrees of the geomagnetic equator at radial distances from about 2 to 6 RE. They propagate in the extraordinary (fast magnetosonic) mode nearly perpendicularly to…
Fine-structure Fe II* Emission and Resonant Mg II Emission in z ~ 1 Star-forming Galaxies
Weiner, Benjamin J.; Martin, Crystal L.; Shapley, Alice E. +3 more
We present a study of the prevalence, strength, and kinematics of ultraviolet Fe II and Mg II emission lines in 212 star-forming galaxies at z ~ 1 selected from the DEEP2 survey. We find Fe II* emission in composite spectra assembled on the basis of different galaxy properties, indicating that Fe II* emission is common at z ~ 1. In these composite…
HST/COS observations of a new population of associated QSO absorbers
Savage, B. D.; Narayanan, A.; Arav, N. +2 more
We present a sample of new population of associated absorbers, detected through Ne VIII λλ770, 780 absorption, in the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) spectra of intermediate-redshift (0.45 < z < 1.21) quasars (QSOs). Our sample comprised of total 12 associated Ne VIII systems detected towards eight lines of sig…
Evidence of quasi-chemically homogeneous evolution of massive stars up to solar metallicity
Martins, F.; Mahy, L.; Russeil, D. +1 more
Context. Long soft gamma-ray bursts (LGRBs) are usually associated with the death of the most massive stars. A large amount of core angular momentum in the phases preceding the explosion is required to form LGRBs. A very high initial rotational velocity can provide this angular momentum. This velocity strongly influences the way the star evolves: …
Saturn's cloud structure inferred from Cassini ISS
Roman, Michael T.; Gierasch, Peter J.; Banfield, Don
Using high-resolution Cassini ISS images with wavelengths ranging from the ultraviolet to the near infrared, we have retrieved Saturn's atmospheric aerosol structure and properties for a broad range of latitudes in the southern hemisphere. The observations are consistent with two distinct layers of haze above a scattered cloud. Each layer is chara…