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Far-Infrared Luminous Supernova Remnant Kes 17
Onaka, Takashi; Jeong, Woong-Seob; Koo, Bon-Chul +4 more
We present the results of infrared (IR; 2.5-160 µm) observations of the supernova remnant (SNR) Kes 17 based on the data obtained with the AKARI and Spitzer satellites. We first detect bright continuum emission of its western shell in the mid- and far-IR wavebands together with its near-IR molecular line emission. We also detect hidden mid-I…
Unraveling the Nature of Unidentified High Galactic Latitude Fermi/LAT Gamma-Ray Sources With Suzaku
Cheung, C. C.; Gehrels, N.; Kanai, Y. +13 more
Here we report on the results of deep X-ray follow-up observations of four unidentified γ-ray sources detected by the Fermi/LAT instrument at high Galactic latitudes using the X-ray Imaging Spectrometers on board the Suzaku satellite. All of the studied objects were detected with high significance during the first three months of Fermi/LAT operati…
N II λλ5668-5712: A New Class of Spectral Features in Eta Carinae
Davidson, Kris; Mehner, Andrea; Ferland, Gary J.
We report on the N II λλ5668-5712 emission and absorption lines in the spectrum of η Carinae. Spectral lines of the stellar wind regions can be classified into four physically distinct categories: (1) low-excitation emission such as H I and Fe II, (2) higher-excitation He I features, (3) the N II lines discussed in this paper, and (4) He II emissi…
On the Nature of the Spectral Line Broadening in Solar Coronal Dimmings
Zhukov, A. N.; Dolla, L. R.
We analyze the profiles of iron emission lines observed in solar coronal dimmings associated with coronal mass ejections, using the EUV Imaging Spectrometer on board Hinode. We quantify line profile distortions with empirical coefficients (asymmetry and peakedness) that compare the fitted Gaussian to the data. We find that the apparent line broade…
Plasma Heating in the Very Early and Decay Phases of Solar Flares
Siarkowski, M.; Falewicz, R.; Rudawy, P.
In this paper, we analyze the energy budgets of two single-loop solar flares under the assumption that non-thermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were observed by RHESSI and GOES on 2002 September 20 and 2002 March 17, respectively. For both investigated flares we derived the ene…
NICMOS Polarimetry of "Polar-scattered" Seyfert 1 Galaxies
Alexander, D. M.; Batcheldor, D.; Young, S. +5 more
The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact equatorial scattering region (ESR), located within the circum-nuclear torus. Here we present NICMOS 2.0 µ…
New Constraints on the Origin of the Short-term Cyclical Variability of the Wolf-Rayet Star WR 46
Talavera, A.; Pollock, A. M. T.; Hénault-Brunet, V. +3 more
The Wolf-Rayet star WR 46 is known to exhibit a very complex variability pattern on relatively short timescales of a few hours. Periodic but intermittent radial velocity shifts of optical lines as well as multiple photometric periods have been found in the past. Non-radial pulsations, rapid rotational modulation, or the presence of a putative low-…
The Solar Decimetric Spike Burst of 2006 December 6: Possible Evidence for Field-aligned Potential Drops in Post-eruption Loops
White, S. M.; Balasubramaniam, K. S.; Cliver, E. W.
A 1.4 GHz solar radio burst associated with a 3B/X6 eruptive flare on 2006 December 6 had the highest peak flux density (~106 sfu) of any event yet recorded at this frequency. The decimetric event characteristics during the brightest emission phase (numerous intense, short-lived, narrow-band bursts that overlapped to form a continuous s…
Discovery of a Candidate Quiescent Low-mass X-Ray Binary in the Globular Cluster NGC 6553
Pavlov, George G.; Guillot, Sebastien; Zavlin, Vyacheslav E. +2 more
This paper reports the search for quiescent low-mass X-ray binaries (qLMXBs) in the globular cluster (GC) NGC 6553 using an XMM-Newton observation designed specifically for that purpose. We spectrally identify one candidate qLMXB in the core of the cluster, based on the consistency of the spectrum with a neutron star H-atmosphere model at the dist…
A Deep Chandra View of the NGC 404 Central Engine
Dalcanton, J. J.; Skillman, E. D.; Weisz, D. R. +7 more
We present the results of a 100 ks Chandra observation of the NGC 404 nuclear region. The long exposure and excellent spatial resolution of Chandra have enabled us to critically examine the nuclear environment of NGC 404, which is known to host a nuclear star cluster and potentially an intermediate-mass black hole (IMBH; on the order of a few time…