Search Publications
Stellar subsystems of the galaxy NGC 1313
Tikhonov, N. A.; Galazutdinova, O. A.
Based on archival Hubble Space Telescope (HST) ACS/WFC images, we have performed stellar photometry for eight fields of the spiral galaxy NGC 1313 and its satellite, the low-mass Sph/Irr galaxy AM0319-662. Stars of various ages have been identified on the constructed Hertzsprung-Russell diagrams: young supergiants, middle-aged stars, and old stars…
O VI 1032 Å intensity and Doppler shift oscillations above a coronal hole: Magnetosonic waves or quasi-periodic upflows?
Raymond, J. C.; Mancuso, S.; Taricco, C. +1 more
On 1996 December 19, the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO) conducted a special high-cadence sit-and-stare observation in the O vi 1032 Å spectral line above a polar coronal hole at a heliocentric distance of 1.38 R⊙. The ~ 9-h dataset was analyzed by applying advanced spec…
Connecting VLBI and Gaia celestial reference frames
Malkin, Zinovy
The current state of the link problem between radio and optical celestial reference frames is considered. The main objectives of the investigations in this direction during the next few years are the preparation of a comparison and the mutual orientation and rotation between the optical Gaia Celestial Reference Frame (GCRF) and the 3rd generation …
SEDEBLEND: a new method for deblending spectral energy distributions in confused imaging
Scott, Douglas; Swinbank, Mark; MacKenzie, Todd P.
For high-redshift submillimetre or millimetre sources detected with single-dish telescopes, interferometric follow-up has shown that many are multiple submillimetre galaxies blended together. Confusion-limited Herschel observations of such targets are also available, and these sample the peak of their spectral energy distribution (SED) in the far-…
Undercover EUV Solar Jets Observed by the Interface Region Imaging Spectrograph
Innes, D. E.; Chen, N. -H.
It is well-known that extreme ultraviolet (EUV) emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions, dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous observations from the Interface Region Imaging Spectrograph, consisting of UV spectra and slit-jaw ima…
Angular Dependence of the Facular-Sunspot Coverage Relation as Derived by MDI Magnetograms
Criscuoli, S.
Previous studies have shown that the variation over the solar magnetic activity cycle of the area of facular/network features identified from broad-band and narrow-band imagery is positively correlated with the sunspot area and number, the relation being described as either linear or quadratic. On the other hand, the temporal variation of the spat…
Contemporaneous Broadband Observations of Three High-redshift BL LAC Objects
Troja, E.; Caraveo, P. A.; Mirabal, N. +101 more
We have collected broadband spectral energy distributions (SEDs) of three BL Lac objects 3FGL J0022.1-1855 (z = 0.689), 3FGL J0630.9-2406 (z\quad ≳ 1.239), and 3FGL J0811.2-7529 (z = 0.774), detected by Fermi with relatively flat gigaelectronvolt spectra. By observing simultaneously in the near-infrared to hard X-ray band, we can well characterize…
Variation of the temperature gradient in the solar photosphere with magnetic activity
Faurobert, M.; Ricort, G.; Balasubramanian, R.
Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Some solar-cycle variations of the quiet-Sun physical structure, such as the temperature gradient or the photospheric radius, might affect the irradiance.
Aims: We intend to investigate possible variations of the photospheric temperature g…
Surrogate-assisted network analysis of nonlinear time series
Laut, Ingo; Räth, Christoph
The performance of recurrence networks and symbolic networks to detect weak nonlinearities in time series is compared to the nonlinear prediction error. For the synthetic data of the Lorenz system, the network measures show a comparable performance. In the case of relatively short and noisy real-world data from active galactic nuclei, the nonlinea…
Two interacting X lines in magnetotail: Evolution of collision between the counterstreaming jets
Retinò, Alessandro; Nakamura, Rumi; Nakamura, Takuma +5 more
We study the process of collision between the counterstreaming jets flowing out from two reconnection sites in the Earth's magnetotail. The X lines, bracketing the region of jets collision, were passing by two Cluster probes successively in tailward direction. Two probes observed two different stages of the collision process. At the jets collision…