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Three clusters of the SMC from ACS/WFC HST archive data: NGC 265, K 29 and NGC 290 and their field population
Chiosi, E.; Vallenari, A.
Aims:We determine the age, metallicity and initial mass function of three clusters, namely
Methods: We make use of ACS/WFC HST arc…
The Stellar Populations in the Outer Regions of M33. II. Deep ACS Imaging
Sarajedini, Ata; Schommer, Robert; Geisler, Doug +2 more
Studying the stellar populations in the outskirts of spiral galaxies can provide important constraints on their structure, formation, and evolution. To that end, we present VI photometry obtained with the Advanced Camera for Surveys for three fields located ~20'-30' in projected distance southeast of M33's nucleus (corresponding to approximately f…
Dissipation of Standing Slow Magnetoacoustic Waves in Hot Coronal Loops
Sigalotti, L. Di G.; Mendoza-Briceño, C. A.; Luna-Cardozo, M.
The damping of standing slow waves in hot (T>6 MK) coronal loops of semicircular shape is revisited in both the linear and nonlinear regimes. Dissipation by thermal conduction, compressive viscosity, radiative cooling, and heating are examined for nonstratified and stratified loops. We find that for typical conditions of hot SUMER loops, therma…
Neon and Oxygen Absolute Abundances in the Solar Corona
Landi, E.; Doschek, G. A.; Feldman, U.
In the present work we use the UV spectrum of a solar flare observed with SOHO SUMER to measure the absolute abundance of Ne in the solar atmosphere. The measurement is carried out using the intensity ratio between the allowed 1s2s3S1-1s2p3P2 Ne IX line at 1248.28 Å and the free-free continuum radiation …
A Spectroscopic Study of Field and Runaway OB Stars
Gies, Douglas R.; Boyajian, Tabetha S.; Grundstrom, Erika D. +1 more
Identifying binaries among runaway O- and B-type stars offers valuable insight into the evolution of open clusters and close binary stars. Here we present a spectroscopic investigation of 12 known or suspected binaries among field and runaway OB stars. We find new orbital solutions for five single-lined spectroscopic binaries (HD 1976, HD 14633, H…
The ISO LWS high-resolution spectral survey towards Sagittarius B2
Cernicharo, José; Polehampton, Edward T.; Swinyard, Bruce M. +5 more
A full spectral survey was carried out towards the giant molecular cloud complex, Sagittarius B2 (SgrB2), using the Infrared Space Observatory (ISO) Long Wavelength Spectrometer (LWS) Fabry-Pérot mode. This provided complete wavelength coverage in the range 47-196µm (6.38-1.53THz) with a spectral resolution of 30-40kms-1. This is …
Unveiling the broad band X-ray continuum and iron line complex in Mrk 841
Maraschi, L.; Nandra, K.; Ponti, G. +7 more
Context:
Aims:
Reconstruction of a bipolar magnetic signature in an earthward jet in the tail: Flux rope or 3D guide-field reconnection?
RèMe, H.; Khotyaintsev, Y.; Hasegawa, H. +4 more
Southward-then-northward magnetic perturbations are often seen in the tail plasma sheet, along with earthward jets, but the generation mechanism of such bipolar Bz (magnetic flux rope created through multiple X-line reconnection, transient reconnection, or else) has been controversial. At ∼2313 UT on 13 August 2002, Cluster encountered …
Unveiling the Core of the Globular Cluster M15 in the Ultraviolet
Knigge, C.; Charles, P. A.; Long, K. S. +4 more
We have obtained deep FUV and NUV images of the inner region of the dense globular cluster M15 with the HST ACS. The FUV-NUV color-magnitude diagram shows a well-defined track of horizontal branch stars, as well as a trail of blue stragglers and white dwarfs. The main-sequence turnoff is clearly visible at FUV~=23.5 mag and FUV-NUV~=3 mag, and the…
Multi-Wavelength Signatures of Magnetic Reconnection of a Flare-Associated Coronal Mass Ejection
Joshi, Bhuwan; Veronig, Astrid M.; Manoharan, P. K. +2 more
The evolution of an X2.7 solar flare, that occurred in a complex βγδ magnetic configuration region on 3 November 2003 is discussed by utilizing a multi-wavelength data set. The very first signature of pre-flare coronal activity is observed in radio wavelengths as a type III burst that occurred several minutes prior to the flare signature in Hα. Th…