Search Publications
A Simultaneous Forbush Decrease Associated with an Earthward Coronal Mass Ejection Observed by STEREO
Yi, Y.; Oh, S. Y.
The intensity-time profile of Forbush decrease (FD) events observed by neutron monitors (NMs) looks like that of a geomagnetic storm as defined by the Dst index. Oh, Yi, and Kim (J. Geophys. Res. 113, A01103, 2008) and Oh and Yi (J. Geophys. Res. 114, A11102, 2009) classified FD events based on the amount of overlap and simultaneity of their main …
Evidence for Fresh Frost Layer on the Bare Nucleus of Comet Hale-Bopp at 32 AU Distance
Pál, András; Sárneczky, Krisztián; Juhász, Attila +4 more
Here, we report that the activity of comet Hale-Bopp ceased between late 2007 and 2009 March, at about 28 AU distance from the Sun. At that time, the comet resided at a distance from the Sun that exceeded the freeze-out distance of regular comets by an order of magnitude. A Herschel Space Observatory PACS scan was taken in mid-2010, in the already…
Herschel and JCMT observations of the early-type dwarf galaxy NGC 205
Boquien, M.; Roussel, H.; Fritz, J. +18 more
We present Herschel dust continuum, James Clerk Maxwell Telescope CO (3-2) observations and a search for [C II] 158 ?m and [O I] 63 ?m spectral line emission for the brightest early-type dwarf satellite of Andromeda, NGC 205. While direct gas measurements [Mg∼ 1.5 × 106 M⊙, H I+ CO (1-0)] have proven to be inconsis…
The XMM-Newton survey of the Small Magellanic Cloud: XMMU J010633.1-731543 and XMMU J010743.1-715953, two new Be/X-ray binary systems★
Haberl, F.; Hatzidimitriou, D.; Mereghetti, S. +6 more
In the course of the XMM-Newton survey of the Small Magellanic Cloud (SMC), two new bright X-ray sources were discovered exhibiting the spectral characteristics of high-mass X-ray binaries - but revealing only weak evidence for pulsations in just one of the objects (at 153 s in XMMU J010743.1-715953). The accurate X-ray source locations permit the…
Ultraviolet Measurements of Interstellar C2
Federman, S. R.; Sheffer, Y.; Hupe, Ryan C.
We analyzed archival spectra acquired with the Hubble Space Telescope for a study of interstellar C2. Absorption from the electronic transitions, D 1Σ+ u - X 1Σ+ g (0,0) as well as F 1Πu - X 1Σ+ g (0,0) and (1,0), was…
Estimates of Emission-Region Locations of Fermi Flat-Spectrum Radio Quasars
Zhang, Li; Yan, Dahai; Zeng, Houdun
We have studied the location of emission regions through modeling the quasi-simultaneous multifrequency spectral energy distributions of 21 Fermi flat-spectrum radio quasars (FSRQs) in the frame of a multicomponent one-zone leptonic model. In our calculations, we took the detailed broad line region (BLR) structure into account, and discussed the e…
New Evidence Supporting Cluster Membership for the Keystone Calibrator Delta Cephei
Gieren, W.; Turner, D.; Majaess, D.
New and existing UBVJHKs , spectroscopic, NOMAD, Hubble Space Telescope, and revised Hipparcos observations are employed to determine properties for δ Cep and its host star cluster. The multi-faceted approach ensured that uncertainties were mitigated (σ/d ~ 2%). The following fundamental parameters were inferred for δ Cep: E(B - V) = 0.…
Observations of Ionospheric Electron Beams in the Plasma Sheet
Parks, G. K.; Fu, S. Y.; Pu, Z. Y. +3 more
Electrons streaming along the magnetic field direction are frequently observed in the plasma sheet of Earth’s geomagnetic tail. The impact of these field-aligned electrons on the dynamics of the geomagnetic tail is however not well understood. Here we report the first detection of field-aligned electrons with fluxes increasing at ∼1keV forming a “…
Antitruncated stellar light profiles in the outer regions of STAGES spiral galaxies: bulge or disc related?
Wolf, Christian; Aragón-Salamanca, Alfonso; Hoyos, Carlos +2 more
We present a comparison of azimuthally averaged radial surface brightness µ(r) profiles and analytical bulge-disc decompositions (de Vaucouleurs, r1/4 bulge plus exponential disc) for spiral galaxies using Hubble Space Telescope/Advanced Camera for Surveys V-band imaging from the Space Telescope A901/2 Galaxy Evolution Survey (STA…
Revealing the sub-structures of the magnetic reconnection separatrix via particle-in-cell simulation
Deng, X. H.; Huang, S. Y.; Yuan, Z. G. +7 more
Magnetic separatrix is an important boundary layer separating the inflow and outflow regions in magnetic reconnection. In this article, we investigate the sub-structures of the separatrix region by using two-and-half dimensional electromagnetic particle-in-cell simulation. The separatrix region can be divided into two sub-regions in terms of the i…