Fourteen years of multifrequency-coordinated observations of the X-ray/Be system A 0535+26/HDE 245770

Giovannelli, F.; Bartolini, C.; Гуарниери, А.; Piccioni, A.; Burger, M.; Dessel, E. L. van; Kurt, V. G.; Sheffer, E. K.; Martino, D. de; Waters, Rens; Martínez‐País, I. G.; Gnedin, Yu. N.; Larionov, V. M.; Shakovskaya, N. I.

doi:10.1007/bf00640700

Cited by 3 publications

(7 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, the UV continuum flux is essentially at the same level as during the October 1980 large X-ray outburst and also during the X-ray quiescent phases in November 1981 and November 1983. Line profile analysis of Si rv and C Iv, averaged during the period of observations gives a terminal velocity of > 600 km s-1 _ in agreement with previous results de Loore et aI., 1984)-which indicates no long-term variations in the polar high-velocity wind (Giovannelli et al, 1990b).…”

Section: Uv Observationssupporting

confidence: 86%

“…Optical photometric UBVRI observations of HDE 245770 carried out in March 1989, during the large campaign of multifrequency observations organized for the expected March 1989 X-ray outburst (Giovannelli et al, 1990b), show that the Be star is at a high level of optical emission in respect to those carried out at the end of 1988. During the whole month no variations larger than 0.05 mag in the UBV bands were detected, with the exception of a few days around 14 March, when an enhancement of the luminosity of the order of 0.1 mag was observed.…”

Section: (A6) Paschen Linesmentioning

confidence: 94%

“…(1983) (103.3 + 0.7 s in the range 30-100keV with an integral flux of ~ 20 mCrab), Giovannelli et al (1984b) (103.3 + 0.1 s in the energy range 2-25 keV with an integral flux of ~ 30 mCrab), and Coe et al (1989) (103.54 + 0.04 s) with an integral flux of the order 20 mCrab, on 21 July, 1981, on 25 October, 1983, and on 29July, 1986, respectively. Figure 6 shows the history of the pulse period changes (Giovannelli et al, 1990a). Figure 7 shows the change in the pulse period of A 0535 + 26 for the December 1977 outburst detected by Prognoz 6, Signe III and SAS 3 satellites (Bouchacourt et al, 1981).…”

Section: X-ray Observationsmentioning

confidence: 96%

“…Recently, during the large campaign of multifrequency observations (from X-ray to IR) concomitant with the predicted March 1989 X-ray outburst, Giovannelli et al (1990b) made also IR broad-band photometric measurements in J, H, K, L, and M bands from 5 March to 26 April. The results show that the IR flux of HDE 245770 was at its highest level in respect to the previous three years, being K = 7.01 + 0.02 mag.…”

mentioning

confidence: 99%

See 3 more Smart Citations

A 0535 + 26/HDE 245770: A typical X-ray/Be system

Giovannelli

Graziati

1992

Space Sci Rev

View full text Add to dashboard Cite

Abstract. Among the X-ray/Be systems, A 0535 + 26/HDE 245770 has been noted, since its discovery, for its peculiar features in several respects, in a wide energy range. For this reason and for a series of concomitant favorable causes, this system has been one of the most studied among the massive X-ray binary systems. The most remarkable incident was that its optical identification with an early-type-emission-line star (O9.7IIie) has led to a deep studies on Be stars and their interactions with neutron stars, which have allowed to discover, without unbiguity, the presence of optical indicators of consequent X-ray flares, as well as that Be stars in X-ray/Be systems behave just as 'normal' Be stars. Overmore, thanks to the multifrequency coordinated observations of this system, the X-ray emissions from binary companion of the Be stars are best explained by assuming the presence of a thick equatorial disk with low expansion velocity and a thin polar region with high expansion velocity. This picture reconciled the strong discrepancy in mass loss rate evaluations coming from IR and from UV measurements, assuming that the observed regions are enterely distinct from each other, one being a high-density, low-velocity region, and the other being a low-density, very hot, rapidly-expanding disk-like zone.Since, this picture seems to be the best up-to-date frame to cuckold all the experimental panorama available on X-ray/Be systems, we would like to paint in this paper the multifrequency behaviour of A 0535 + 26/HDE 245770, which is the best studied among such systems, in order to stimulate future coordinated experimental-theoretical works on this very interesting class of objects.

show abstract

Section: Uv Observationssupporting

confidence: 86%

Section: (A6) Paschen Linesmentioning

confidence: 94%

Section: X-ray Observationsmentioning

confidence: 96%

mentioning

confidence: 99%

See 2 more Smart Citations

A 0535 + 26/HDE 245770: A typical X-ray/Be system

Giovannelli

Graziati

1992

Space Sci Rev

View full text Add to dashboard Cite

show abstract

“…It is possible, either due to an unusually quiet state of the Be star (which implies a low value forṀ and so a long P eq ) or to its long-term average spin-up (a progressive reduction in P), that the pulsar can acquire a state in which it remains fast (P < P eq ) during the whole orbital cycle, including its periastron passage, as occurred, for instance, in 1985-86 (Giovannelli et al 1986) and perhaps also during the period of the observations reported in the present paper.…”

Section: Discussionmentioning

confidence: 99%

HeI doubled emission lines from A0535+26 ≡ HDE 245770

Giovannelli

Bernabei

Rossi

et al. 2007

A&A

Self Cite

View full text Add to dashboard Cite

We report results of the spectroscopy for V725 Tau (HDE 245770, BD +26• 883), commonly known as Flavia's star, which is the optical counterpart of the X-ray pulsar A0535+26, carried out at the 1.5 m Loiano telescope during one run of observations of this star spread over a period of years. The HeI emission lines clearly show doubling, which is good evidence for the presence of a disc. In this paper we critically discuss the possibility that this disc is a temporary accretion disc around the neutron star, a view that contrasts to the usual interpretation, which considers that this sort of doubling in the HeI emission lines is due to a disc formed by gas expelled from the Be star. In the former case the outer radius of the accretion disc could range from 5.9 × 10 10 cm to 2.1 × 10 11 cm, taking the most probable range into account for the orbital inclination of the binary system, from 35• to 39• . The presence of such a temporary accretion disc around the neutron star was predicted by Giovannelli & Ziółkowski (1990).

show abstract

The Impact of Space Experiments on Our Knowledge of the Physics of the Universe

Giovannelli

Sabau-Graziati

2004

The Impact of Space Experiments on Our Knowledge of the Physics of the Universe

View full text Add to dashboard Cite

Fourteen years of multifrequency-coordinated observations of the X-ray/Be system A 0535+26/HDE 245770

Cited by 3 publications

References 8 publications

A 0535 + 26/HDE 245770: A typical X-ray/Be system

A 0535 + 26/HDE 245770: A typical X-ray/Be system

HeI doubled emission lines from A0535+26 ≡ HDE 245770

The Impact of Space Experiments on Our Knowledge of the Physics of the Universe

Contact Info

Product

Resources

About