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Related papers: Explosive events on sub-arcsecond scale in IRIS ob…

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We have measured the scintillation properties of 151 young, energetic pulsars with the Parkes radio telescope and have identified two extreme scattering events (ESEs). Towards PSR J1057-5226 we discovered a three-year span of strengthened…

High Energy Astrophysical Phenomena · Physics 2017-12-27 M. Kerr , W. A. Coles , C. A. Ward , S. Johnston , A. V. Tuntsov , R. M. Shannon

Results from the Solar Maximum Mission showed a close connection between the hard X-ray and transition region emission in solar flares. Analogously, the modern combination of RHESSI and IRIS data can inform the details of heating processes…

Solar and Stellar Astrophysics · Physics 2016-08-31 Jeffrey W. Reep , Harry P. Warren , Nicholas A. Crump , Paulo J. A. Simoes

We have carried out the first comprehensive investigation of enhanced line emission from molecular hydrogen, H$_{2}$ at 1333.79 {\AA}, observed at flare ribbons in SOL2014-04-18T13:03. The cool H$_{2}$ emission is known to be fluorescently…

Solar and Stellar Astrophysics · Physics 2021-02-24 Sargam M. Mulay , Lyndsay Fletcher

Small-scale explosive events or microflares occur throughout the chromospheric network of the Sun. They are seen as sudden bursts of highly Doppler shifted spectral lines of ions formed at temperatures in the range 2x10^4 - 5x10^5 K. They…

Astrophysics · Physics 2015-06-24 D. E. Innes , G. Toth

The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft observed flare footpoint regions coincident with a surge for a M3.7 flare observed on 25 September 2011 at N12 E33 in active region 11302. The flare was observed in…

Solar and Stellar Astrophysics · Physics 2015-10-30 George A. Doschek , Harry P. Warren , Brian R. Dennis , Jeffrey W. Reep , Amir Caspi

We present optical photometric and spectroscopic observations of the peculiar Type Ia supernova ASASSN-20jq/SN 2020qxp. It is a low-luminosity object with a peak absolute magnitude of $M_B=-17.1\pm0.5$ mag. Despite its low luminosity, its…

The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33-0.4 arcsec spatial resolution, 2 s temporal…

Persistent plasma upflows were observed with Hinode's EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR,…

We present near-infrared medium-resolution ($R \sim 875$) spectra of the microquasar GRS 1915+105 on 1997 August 13-15 UTC from the Hale 200-inch telescope. The spectra showed broad emission lines of He I (2.058 $\mu$m) and H I (2.166…

Doppler shifts in chromospheric and transition-region lines during solar flares are often interpreted as chromospheric condensation or evaporation. However, alternative sources of Doppler-shifted emission have been suggested, such as…

Solar and Stellar Astrophysics · Physics 2025-09-08 Luke H. Majury , Ryan O. Milligan

We report on four large filament eruptions (FEs) from solar cycles 23 and 24 that were associated with large solar energetic particle (SEP) events and interplanetary type II radio bursts. The post-eruption arcades corresponded to mostly…

Solar and Stellar Astrophysics · Physics 2015-06-11 N. Gopalswamy , P. Makela , S. Akiyama , S. Yashiro , H. Xie , N. Thakur , S. W. Kahler

A variety of periodic phenomena have been observed in conjunction with large solar jets. We aim to find further evidence for {(quasi-)}periodic behaviour in solar jets and determine what the periodic behaviour can tell us about the…

Solar and Stellar Astrophysics · Physics 2015-06-04 R. J. Morton , A. K. Srivastava , R. Erdélyi

We have studied a complex metric radio event which originated in a compact flare, observed with the ARTEMIS-JLS radiospectro-graph on February 12, 2010. The event was associated with a surge observed at 195 and 304 {\AA} and with a coronal…

Solar and Stellar Astrophysics · Physics 2021-10-20 C. E. Alissandrakis , A. Nindos , S. Patsourakos , A. Hillaris

High-resolution observations of dynamic phenomena give insight into properties and processes that govern the low solar atmosphere. We present the analysis of jet-like phenomena emanating from a penumbral foot-point in active region (AR)…

Solar and Stellar Astrophysics · Physics 2020-10-09 Llŷr Dafydd Humphries , Erwin Verwichte , David Kuridze , Huw Morgan

In recent years, with an increasing number of type Ia supernovae (SNe Ia) discovered soon after their explosions, a non-negligible fraction of SNe Ia with early-excess emissions (EExSNe Ia) have been confirmed. In this letter, we present a…

We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of active…

Solar and Stellar Astrophysics · Physics 2019-07-17 S. L. Guglielmino , F. Zuccarello , P. R. Young , P. Romano , M. Murabito

Ellerman bombs (EBs) have been widely studied over the past two decades; however, only recently have counterparts of these events been observed in the quiet-Sun. The aim of this article is to further understand small-scale quiet-Sun…

Solar and Stellar Astrophysics · Physics 2017-08-16 C. J. Nelson , N. Freij , A. Reid , R. Oliver , M. Mathioudakis , R. Erdélyi

Here we present the study of a compact emission source during an X1.3 flare on 2022-March-30. Within a $\sim41$~s period (17:34:48 UT to 17:35:29 UT), IRIS observations show spectral lines of Mg II, C II and Si IV with extremely broadened,…

Solar and Stellar Astrophysics · Physics 2023-09-13 Yan Xu , Graham S. Kerr , Vanessa Polito , Nengyi Huang , Ju Jing , Haimin Wang

One of the key processes associated with the "standard" flare model is chromospheric evaporation, a process where plasma heated to high temperatures by energy deposition at the flare footpoints is driven upwards into the corona. Despite…