STIX X-ray microflare observations during the Solar Orbiter commissioning phase

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F21%3A00552543" target="_blank" >RIV/67985815:_____/21:00552543 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202140524" target="_blank" >https://doi.org/10.1051/0004-6361/202140524</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202140524" target="_blank" >10.1051/0004-6361/202140524</a>

Jazyk výsledku

angličtina

Název v původním jazyce

STIX X-ray microflare observations during the Solar Orbiter commissioning phase

Popis výsledku v původním jazyce

We report the first STIX observations of solar microflares recorded during the instrument commissioning phase in order to investigate the STIX performance at its detection limit. For the observed microflares of the GOES A and B class, the STIX peak time at lowest energies is located in the impulsive phase of the flares, well before the GOES peak time. Such a behavior can either be explained by the higher sensitivity of STIX to higher temperatures compared to GOES, or due to the existence of a nonthermal component reaching down to low energies. The interpretation is inconclusive due to limited counting statistics for all but the largest flare in our sample. For this largest flare, the low-energy peak time is clearly due to thermal emission, and the nonthermal component seen at higher energies occurs even earlier. This suggests that the classic thermal explanation might also be favored for the majority of the smaller flares. In combination with EUV and soft X-ray observations, STIX corroborates earlier findings that an isothermal assumption is of limited validity. Future diagnostic efforts should focus on multi-wavelength studies to derive differential emission measure distributions over a wide range of temperatures to accurately describe the energetics of solar flares. Conclusions. Commissioning observations confirm that STIX is working as designed. As a rule of thumb, STIX detects flares as small as the GOES A class. For flares above the GOES B class, detailed spectral and imaging analyses can be performed.n

Název v anglickém jazyce

STIX X-ray microflare observations during the Solar Orbiter commissioning phase

Popis výsledku anglicky

We report the first STIX observations of solar microflares recorded during the instrument commissioning phase in order to investigate the STIX performance at its detection limit. For the observed microflares of the GOES A and B class, the STIX peak time at lowest energies is located in the impulsive phase of the flares, well before the GOES peak time. Such a behavior can either be explained by the higher sensitivity of STIX to higher temperatures compared to GOES, or due to the existence of a nonthermal component reaching down to low energies. The interpretation is inconclusive due to limited counting statistics for all but the largest flare in our sample. For this largest flare, the low-energy peak time is clearly due to thermal emission, and the nonthermal component seen at higher energies occurs even earlier. This suggests that the classic thermal explanation might also be favored for the majority of the smaller flares. In combination with EUV and soft X-ray observations, STIX corroborates earlier findings that an isothermal assumption is of limited validity. Future diagnostic efforts should focus on multi-wavelength studies to derive differential emission measure distributions over a wide range of temperatures to accurately describe the energetics of solar flares. Conclusions. Commissioning observations confirm that STIX is working as designed. As a rule of thumb, STIX detects flares as small as the GOES A class. For flares above the GOES B class, detailed spectral and imaging analyses can be performed.n

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

656

Číslo periodika v rámci svazku

December

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

19

Strana od-do

A4

Kód UT WoS článku

000730246400014

EID výsledku v databázi Scopus

2-s2.0-85121574240