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Wave propagation in a solar quiet region and the influence of the magnetic canopy
Tziotziou, K.; Tsiropoula, G.; Kontogiannis, I.
Aims: We seek indications or evidence of transmission/conversion of magnetoacoustic waves at the magnetic canopy, as a result of its impact on the properties of the wave field of the photosphere and chromosphere.
Methods: We use cross-wavelet analysis to measure phase differences between intensity and Doppler signal oscillations in the H…
On the Absence of EUV Emission from Comet C/2012 S1 (ISON)
Pesnell, W. Dean; Bryans, Paul
When the sungrazing comet C/2012 S1 (ISON) made its perihelion passage within two solar radii of the Sun’s surface, it was expected to be a bright emitter at extreme ultraviolet (EUV) wavelengths. However, despite solar EUV telescopes repointing to track the orbit of the comet, no emission was detected. This “null result” is interesting in its own…
X-ray nova MAXI J1828-249. Evolution of the broadband spectrum during its 2013-2014 outburst
Grebenev, S. A.; Burenin, R. A.; Krivonos, R. A. +2 more
Based on data from the SWIFT, INTEGRAL, MAXI/ISS orbital observatories, and the ground-based RTT-150 telescope, we have investigated the broadband (from the optical to the hard X-ray bands) spectrum of the X-ray nova MAXI J1828-249 and its evolution during the outburst of the source in 2013-2014. The optical and infrared emissions from the nova ar…
Formation of a solar Hα filament from orphan penumbrae
Solanki, S. K.; Lagg, A.; van Noort, M. +1 more
Aims: The formation and evolution of an Hα filament in active region (AR) 10953 is described.
Methods: Observations from the Solar Optical Telescope (SOT) aboard the Hinode satellite starting from UT 18:09 on 27th April 2007 until UT 06:08 on 1st May 2007 were analysed. 20 scans of the 6302 Å Fe I line pair recorded by SOT/SP were invert…
Hard X-Ray Emission from Sh 2-104: A NuSTAR Search for Gamma-Ray Counterparts
Harrison, F. A.; Stern, D.; Zhang, W. W. +11 more
We present NuSTAR hard X-ray observations of Sh 2-104, a compact H II region containing several young massive stellar clusters (YMSCs). We have detected distinct hard X-ray sources coincident with localized VERITAS TeV emission recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. Fainter, diffuse X-rays coincident…
Searching for narrow absorption and emission lines in XMM-Newton spectra of gamma-ray bursts
D'Avanzo, P.; Campana, S.; Tagliaferri, G. +7 more
We present the results of a spectroscopic search for narrow emission and absorption features in the X-ray spectra of long gamma-ray burst (GRB) afterglows. Using XMM-Newton data, both EPIC and RGS spectra, of six bright (fluence > 10-7 erg cm-2) and relatively nearby (z = 0.54-1.41) GRBs, we performed a blind search for em…
Dealing with missing data in the MICROSCOPE space mission: An adaptation of inpainting to handle colored-noise data
Bergé, Joel; Métris, Gilles; Touboul, Pierre +2 more
The MICROSCOPE space mission, launched on April 25, 2016, aims to test the weak equivalence principle (WEP) with a 10-15 precision. Reaching this performance requires an accurate and robust data analysis method, especially since the possible WEP violation signal will be dominated by a strongly colored noise. An important complication is…
Envelope overshooting in low-metallicity intermediate- and high-mass stars: a test with the Sagittarius dwarf irregular galaxy
Slemer, Alessandra; Marigo, Paola; Bianchi, Luciana +5 more
We check the performance of the Padova TRieste Stellar Evolution Code (PARSEC) tracks in reproducing the blue loops of intermediate age and young stellar populations at very low metallicity. We compute new evolutionary PARSEC tracks of intermediate- and high-mass stars from 2 to 350 M⊙ with enhanced envelope overshooting (EO), EO = 2H
Seasonal variation of Titan's haze at low and high altitudes from HST-STIS spectroscopy
Karkoschka, Erich
The Space Telescope Imaging Spectrograph accumulated image cubes of Titan in five years between 1997 and 2004 that we calibrated and analyzed. The observations probe Titan's early northern fall to early winter. Methane bands between 543 and 990 nm wavelength are well resolved spectrally, and Titan's latitudinal and center-to-limb reflectivity vari…
Coronal electron density distributions estimated from CMEs, DH type II radio bursts, and polarized brightness measurements
Moon, Y. -J.; Lee, Kyoung-Sun; Kim, R. -S. +2 more
We determine coronal electron density distributions (CEDDs) by analyzing decahectometric (DH) type II observations under two assumptions. DH type II bursts are generated by either (1) shocks at the leading edges of coronal mass ejections (CMEs) or (2) CME shock-streamer interactions. Among 399 Wind/WAVES type II bursts (from 1997 to 2012) associat…