An exceptional X-ray flare on the dMe star EQ1839.6 + 8002

Pan, H. C.; Jordan, C.; Makishima, Kazuo; Stern, Robert; Hayashida, Kentaro; Inda-Koide, Mika

doi:10.1093/mnras/285.4.735

Cited by 19 publications

(19 citation statements)

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“…A detailed study of the spectral behaviour of this source is beyond the aim of this paper. Nevertheless, following Pan et al (1997), the LECS and MECS spectra of both observations are well described by a thermal model (R- model in XSPEC, Raymond & Smith 1977), with a temperature kT ∼ 1.8 keV and a 2-10 keV flux of 9.5 × 10 −14 erg cm −2 s −1…”

Section: The 1e 18396+8002 Fieldmentioning

confidence: 77%

BeppoSAX/PDS serendipitous detections at high galactic latitudes

Landi

Malizia

Bassani

2005

A&A

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Abstract. At a flux limit of ∼10−11 erg cm −2 s −1 in the 20-100 keV band, the PDS instrument on-board BeppoSAX offers the opportunity to study the extragalactic sky with an unprecedented sensitivity. In this work we report on the results of a search in the BeppoSAX archive for serendipitous high energy sources at high galactic latitudes (|b| ≥ 13• ). We have defined a set of twelve regions in which the PDS/MECS cross-calibration constant is higher than the nominal value. We attribute this mismatch to the presence of a serendipitous source in the PDS field of view. In four cases the likely high energy emitter is also present in the MECS field of view. In these cases, we have performed a broad band spectral analysis (1.5-100 keV) to understand the source spectral behaviour and compare it with previous BeppoSAX observations when available. In eight cases the identification of the source likely to provide the PDS spectrum is based on indirect evidence (extrapolation to lower energies and/or comparison with previous observations). This approach led to the discovery of six new hard X-ray emitting objects (PKS 2356-611, 2MASX J14585116-1652223, NGC 1566, NGC 7319, PKS 0101-649 and ESO 025-G002) and to the presentation the PDS spectrum of NGC 3227 for the first time. In the remaining five cases we provide extra BeppoSAX observations that can be compared with measurements already published and/or in the archive.

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Section: The 1e 18396+8002 Fieldmentioning

confidence: 77%

BeppoSAX/PDS serendipitous detections at high galactic latitudes

Landi

Malizia

Bassani

2005

A&A

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“…However, few flares have been reported earlier from dMe stars, where peak X‐ray flare luminosity reached up to 30 per cent of bolometric luminosity (e.g. GINGA EQ 1839.6+8002 –Pan et al 1997; EV Lac –Favata et al 2000c; AB Dor –Maggio et al 2000). The total energy released during the X‐ray flares observed in our sample was found to be of the order of 10 35‐37 erg.…”

Section: Discussionmentioning

confidence: 99%

A study of X-ray flares - II. RS CVn-type binaries

Pandey

Singh

2011

Monthly Notices of the Royal Astronomical Society

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We present an analysis of seven flares detected from five RS CVn‐type binaries (UZ Lib, σ Gem, λ And, V711 Tau and EI Eri) observed with XMM–Newton observatory. The quiescent state X‐ray luminosities in the energy band of 0.3–10.0 keV of these stars were found to be 1030.7‐30.9 erg s−1. The exponential decay time in all the sample of flares range from ∼1 to 8 h. The luminosity at peak of the flares in the energy band of 0.3–10.0 keV was found to be in the range of 1030.8–1031.8 erg s−1. The great sensitivity of the XMM‐European Photon Imaging Camera instrument allowed us to perform time resolved spectral analysis during the flares and also in the subsequent quiescent phases. The derived metal abundances of coronal plasma were found to vary during the flares observed from σ Gem, V771 Tau and EI Eri. In these flares elemental abundances found to be enhanced by factors of ∼1.3–1.5 to the quiescent states. In most of the flares, the peak temperature was found to be more than 100 MK, whereas emission measure increased by factors of 1.5–5.5. Significant sustained heating was present in the majority of flares. The loop lengths (L) derived for flaring structure were found to be in the order of 1010‐11 cm and are smaller than the stellar radii (R★), i.e. L/R★≲ 1. The flare from σ Gem showed a high and variable absorption column density during the flare.

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“…Temperatures of the order of 10 8 K are quite common in the flaring coronae of active cool stars. For example, Stern et al (1992) during a flare on Algol, while Pan et al (1997) find 10 8 K during a flare on EQ1839.6+8002. There is ample evidence for temperatures in excess of 10 7 K in the quiescent state of II Peg (Griffiths & Jordan 1998).…”

Section: Discussionmentioning

confidence: 99%

White-light oscillations during a flare on II Peg

Mathioudakis

Seiradakis

Williams

et al. 2003

A&A

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Abstract. We analyse the intensity oscillations observed in the gradual phase of a white-light flare on the RS CVn binary II Peg. Fast Fourier Transform power spectra and Wavelet analysis reveal a period of 220 s. The reliability of the oscillation is tested using several criteria. Oscillating coronal loop models are used to derive physical parameters such as temperature, electron density and magnetic field strength associated with the coronal loop. The derived parameters are consistent with the nearsimultaneous X-ray observations of the flare. There is no evidence for oscillations in the quiescent state of the binary.

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An exceptional X-ray flare on the dMe star EQ1839.6 + 8002

Cited by 19 publications

References 0 publications

BeppoSAX/PDS serendipitous detections at high galactic latitudes

BeppoSAX/PDS serendipitous detections at high galactic latitudes

A study of X-ray flares - II. RS CVn-type binaries

White-light oscillations during a flare on II Peg

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