Results 51 to 60 of about 2,361 (168)

Homogenizing SOHO/EIT and SDO/AIA 171 Å Images: A Deep-learning Approach

The Astrophysical Journal Supplement Series, 2023
Extreme-ultraviolet (EUV) images of the Sun are becoming an integral part of space weather prediction tasks. However, having different surveys requires the development of instrument-specific prediction algorithms.
Subhamoy Chatterjee, Andrés Muñoz-Jaramillo, Maher A. Dayeh, Hazel M. Bain, Kimberly Moreland   +4 more
doaj   +1 more source

Markov‐Chain Monte Carlo Reconstruction of Emission Measure Distributions: Application to Solar Extreme‐Ultraviolet Spectra

The Astrophysical Journal, 1998
We have developed a new method for the reconstruction of differential emission measure distributions based on a Metropolis Markov-chain Monte Carlo (MCMC[M]) method. This technique allows us to (1) relax nonphysical smoothness constraints generally imposed on DEMs, (2) determine confidence bounds on the computed values, and (3) include extra ...
Vinay Kashyap, Jeremy J. Drake
openaire   +1 more source

Hinode EIS: Updated In-flight Radiometric Calibration

The Astrophysical Journal Supplement Series
We present an update to the in-flight radiometric calibration of the Hinode Extreme Ultraviolet Imaging Spectrometer (EIS), revising and extending our previous studies.
G. Del Zanna, M. J. Weberg, H. P. Warren
doaj   +1 more source

FexiEmission Lines in a High‐Resolution Extreme‐Ultraviolet Active Region Spectrum Obtained by the Solar Extreme Ultraviolet Research Telescope and Spectrograph

The Astrophysical Journal, 2005
New calculations of radiative rates and electron impact excitation cross sections for Fe XI are used to derive emission-line intensity ratios involving 3s23p4-3s23p33d transitions in the 180-223 A wavelength range. These ratios are subsequently compared with observations of a solar active region obtained during the 1995 flight of the Solar Extreme ...
Keenan, Francis, Aggarwal, Kanti, Ryans, Robert, Milligan, Ryan, Bloomfield, Shaun, Brosius, J.W., Davila, J.M., Thomas, R.J.   +7 more
openaire   +2 more sources

Extreme‐Ultraviolet Emission Lines of Sxin Solar Flare and Active Region Spectra

The Astrophysical Journal, 2004
R-matrix calculations of electron impact excitation rates in N-like S X are used to derive theoretical emission-line intensity ratios involving 2s22p3-2s2p4 transitions in the 189-265 A wavelength range. A comparison of these with observational data for solar flares and active regions, obtained with the Naval Research Laboratory's S082A spectrograph on
F. P. Keenan, A. C. Katsiyannis, K. G. Widing   +2 more
openaire   +1 more source

Nonthermal Velocities in a Solar Active Region Observed by SERTS

The Astrophysical Journal
We present measurements of coronal nonthermal Doppler velocities in NOAA Active Region 7870 observed by the Solar EUV Research Telescope and Spectrograph during its 1995 sounding rocket flight (SERTS-95).
Jeffrey W. Brosius
doaj   +1 more source

High precision, high time-cadence measurements of the MgII index of solar activity by the GOES-R Extreme Ultraviolet Irradiance Sensor 2: EUVS-C initial flight performance

Journal of Space Weather and Space Climate
EUVS-C is one component of the Extreme Ultraviolet Irradiance Sensor (EUVS) instrument. EUVS, together with the X-ray sensor (XRS), comprise the Extreme Ultraviolet and X-ray Irradiances Sensors (EXIS) investigation (Machol JL et al. 2020.
McClintock William E., Snow Martin, Eden Thomas D., Eparvier Francis G., Machol Janet L., Woodraska Donald L.   +5 more
doaj   +1 more source

Solar Observations of High‐Temperature Emission with the Extreme‐Ultraviolet Imaging Spectrometer onHinode

The Astrophysical Journal, 2008
We present an analysis of solar coronal emission lines formed above 2.5 MK observed with the Extreme-Ultraviolet Imaging Spectrometer on Hinode during a small flare. Our main purpose is to evaluate the internal consistency of the atomic data available for the observed emission.
Harry P. Warren, Uri Feldman, Charles M. Brown   +2 more
openaire   +1 more source

Extreme-ultraviolet Synthesis of Nanojet-like Ejections due to Coalescing Flux Ropes

The Astrophysical Journal Letters
Detection and characterization of small-scale energetic events such as nanoflares and nanojets remain challenging owing to their short lifetimes, small spatial extent, and relatively low energy release, despite their potential role in coronal heating ...
Samrat Sen, A. Ramada C. Sukarmadji, D. Nóbrega-Siverio, F. Moreno-Insertis, J. Martínez-Sykora, Patrick Antolin   +5 more
doaj   +1 more source

Detecting Solar Flare Precursors Using DEFT

The Astrophysical Journal
The Detection and EUV Flare Tracking (DEFT) tool automatically identifies flare precursors in extreme ultraviolet (EUV) observations in a fast and consistent manner, with minimal computational overhead. DEFT currently uses GOES/SUVI 304 Å observations to
Larisza D. Krista
doaj   +1 more source