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On Spectral Breaks in the Power Spectra of Magnetic Fluctuations in Fast Solar Wind between 0.3 and 0.9 AU
Maksimovic, M.; Alexandrova, O.; Marsch, E. +1 more
We analyze the radial variation of the power spectra of the magnetic field from 0.3 to about 0.9 AU, using Helios 2 spacecraft measurements in the fast solar wind. The time resolution of the magnetic field data allows us to study the power spectra up to 2 Hz. Generally, the corresponding spectral break frequency fb and the Doppler-shift…
Magnetosheath pressure pulses: Generation downstream of the bow shock from solar wind discontinuities
Eastwood, J. P.; Horbury, T. S.; Archer, M. O.
We present multipoint Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations of transient dynamic pressure pulses in the magnetosheath 3-10 times the background in amplitude, due to enhancements in both the ion density and velocity. Their spatial dimensions are of the order of ∼1 RE parallel to the flo…
The importance of plasma β conditions for magnetic reconnection at Saturn's magnetopause
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +7 more
Magnetic reconnection is an important process that occurs at the magnetopause boundary of Earth's magnetosphere because it leads to transport of solar wind energy into the system, driving magnetospheric dynamics. However, the nature of magnetopause reconnection in the case of Saturn's magnetosphere is unclear. Based on a combination of Cassini spa…
Re-evaluating WASP-12b: Strong Emission at 2.315 µm, Deeper Occultations, and an Isothermal Atmosphere
Barman, Travis; Crossfield, Ian J. M.; Kodama, Tadayuki +2 more
We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 µm) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% ± 0.06%, corresponding to a brightness temperature of 3640 ± 230 K; second, recent Spitzer/Infrared Array …
GOODS-Herschel: ultra-deep XMM-Newton observations reveal AGN/star-formation connection
Magnelli, B.; Altieri, B.; Aussel, H. +30 more
Models of galaxy evolution assume some connection between the AGN and star formation activity in galaxies. We use the multi-wavelength information of the CDFS to assess this issue. We select the AGNs from the 3 Ms XMM-Newton survey and measure the star-formation rates of their hosts using data that probe rest-frame wavelengths longward of 20 &micr…
Understanding SDO/AIA Observations of the 2010 June 13 EUV Wave Event: Direct Insight from a Global Thermodynamic MHD Simulation
Lugaz, Noé; Downs, Cooper; Roussev, Ilia I. +2 more
In this work, we present a comprehensive observation and modeling analysis of the 2010 June 13 extreme-ultraviolet (EUV) wave observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). Due to extreme advances in cadence, resolution, and bandpass coverage in the EUV regime, the AIA instrument offers an unprecede…
High-velocity clouds as streams of ionized and neutral gas in the halo of the Milky Way
Lehner, N.; Fox, A. J.; Tripp, T. M. +4 more
High-velocity clouds (HVCs), fast-moving ionized and neutral gas clouds found at high galactic latitudes, may play an important role in the evolution of the Milky Way. The extent of this role depends sensitively on their distances and total sky covering factor. We search for HVC absorption in Hubble Space Telescope high-resolution ultraviolet (UV)…
Measurement of Galactic Logarithmic Spiral Arm Pitch Angle Using Two-dimensional Fast Fourier Transform Decomposition
Davis, Benjamin L.; Kennefick, Daniel; Kennefick, Julia +5 more
A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have been almost exclusively qualitative. We have developed a methodology, utilizing two-dimensional fast Fourier …
The blue UV slopes of z ~ 4 Lyman break galaxies: implications for the corrected star formation rate density
Maiolino, R.; Castellano, M.; Pentericci, L. +13 more
Context. Study of the dust extinction in high-redshift galaxies is fundamental to obtaining an estimate of the corrected star formation rate density (SFRD) and to put constraints on galaxy evolution models.
Aims: We plan to analyse dust extinction in Lyman break galaxies (LBGs) by introducing a new and more reliable approach to their selectio…
Inferences on the Distribution of Lyα Emission of z ~ 7 and z ~ 8 Galaxies
Stiavelli, Massimo; Treu, Tommaso; Trenti, Michele +2 more
Spectroscopic confirmation of galaxies at z ~ 7 and above has been extremely difficult, owing to a drop in intensity of Lyα emission in comparison with samples at z ~ 6. This crucial finding could potentially signal the ending of cosmic reionization. However, it is based on small data sets, often incomplete and heterogeneous in nature. We introduc…