Multimission observations of the old nova GK Per during the 2015 outburst

Zemko, Polina; Orio, Marina; Luna, G. J. M.; Mukai, K.; Evans, P. A.; Bianchini, A.

doi:10.1093/mnras/stx851

Cited by 16 publications

(14 citation statements)

References 55 publications

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“…For T CrB, RS Oph, BX Mon, V3890 Sgr & V745 Sco the secondaries are in the range of M2 III -M5.5 III types and for GK Per the secondary is K5 V type. These results are in line with the fact that recurrence period of the systems with M-type giants are ∼ 20 -80 yrs as the mass loss rate of M type giants ∼ 10 −5 -10 −6 M /yr (Wannier & Sahai 1986, Zemko et al 2017. For the classical nova GK Per mass accretion rate is much slower (∼ 10 −8 M /yr) (Zemko et al 2017) due to K type secondary.…”

Section: Summary and Discussionsupporting

confidence: 83%

Photoionization modelling of quiescence-phase spectra of novae and a symbiotic star

Mondal

Das

Anupama

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Using observed and published spectra in the optical region, we have studied a handful of novae and symbiotic stars that show novae-like variability in the quiescence phase. We present results for the novae T Coronae Borealis, GK Persei, RS Ophiuchi, V3890 Sagittarii and V745 Scorpii, and for a symbiotic star BX Monocerotis. Observations were carried out at the 2-m Himalayan Chandra Telescope (HCT). Generally, the spectra show prominent low-ionization emission features of hydrogen, helium, iron and oxygen and TiO absorption features resulting from the cool secondary component; T Coronae Borealis and GK Persei show higher ionization lines. We used the photoionization code cloudy to model these spectra. From the best-fitting models, we have estimated the physical parameters (e.g. temperature, luminosity and hydrogen density), the elemental abundances and other parameters related to the system. By matching the spectra of various giants with the absorption features and using the best fit, we have determined the types of secondaries and also their contribution to the spectra.

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Section: Summary and Discussionsupporting

confidence: 83%

Photoionization modelling of quiescence-phase spectra of novae and a symbiotic star

Mondal

Das

Anupama

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Therefore, the states of the system with the very different accretion rates are observed, so the magnetospheric radius in this system is expected to differ in quiescence and outburst. We attempted to investigate whether this is indeed the case (Suleimanov et al 2016) using a NuSTAR observation of GK Per during the latest outburst (Zemko et al 2017), and Swift/BAT and INTEGRAL hard X-ray spectra of the source in quiescence. This allowed to estimate the magnetosphere size respectively using observed break frequency, and from PSR model under assumption that the mass of WD is the same in both cases.…”

Section: Nustar Observations Of Gk Permentioning

confidence: 99%

Hard X-ray view on intermediate polars in theGaiaera

Suleimanov

Doroshenko

Werner

2018

Monthly Notices of the Royal Astronomical Society

121

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The hardness of the X-ray spectra of intermediate polars (IPs) is determined mainly by the white dwarf (WD) compactness (mass-radius ratio, M/R) and, thus, hard X-ray spectra can be used to constrain the WD mass. An accurate mass estimate requires the finite size of the WD magnetosphere R m to be taken into the account. We suggested to derive it either directly from the observed break frequency in power spectrum of X-ray or optical lightcurves of a polar, or assuming the corotation. Here we apply this method to all IPs observed by NuSTAR (10 objects) and Swift/BAT (35 objects). For the dwarf nova GK Per we also observe a change of the break frequency with flux, which allows to constrain the dependence of the magnetosphere radius on the mass-accretion rate. For our analysis we calculated an additional grid of twoparameter (M and R m /R) model spectra assuming a fixed, tall height of the accretion column H sh /R = 0.25, which is appropriate to determine WD masses in low mass-accretion IPs like EX Hya. Using the Gaia Data Release 2 we obtain for the first time reliable estimates of the mass-accretion rate and the magnetic field strength at the WD surface for a large fraction of objects in our sample. We find that most IPs accrete at rate of ∼ 10 −9 M yr −1 , and have magnetic fields in the range 1-10 MG. The resulting WD mass average of our sample is 0.79 ± 0.16 M , which is consistent with earlier estimates.

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“…At a distance of 10 kpc (see Section 5.1.2), this would imply an absolute X-ray luminosity of ∼ 7.8 × 10 37 erg s −1 (in the range 15 -50 Å; 0.248 -0.827 KeV), which seems absurd because it is four orders of magnitude higher compared to heated polar caps of magnetic CVs (e.g. Zemko et al 2017 and references therein; see also Section 5.4). It is worth noting that even at shorter distances (3 -5 kpc; see Appendix A) this luminosity is still three orders of magnitude higher compared to heated polar caps of magnetic CVs.…”

Section: Chandra High-resolution X-ray Spectroscopymentioning

confidence: 99%

Multiwavelength observations of V407 Lupi (ASASSN-16kt) – a very fast nova erupting in an intermediate polar

Aydi

Orio

Beardmore

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present a detailed study of the 2016 eruption of nova V407 Lupi (ASASSN-16kt), including optical, near-infrared, X-ray, and ultraviolet data from SALT, SMARTS, SOAR, Chandra, Swift, and XMM-Newton. Timing analysis of the multiwavelength light-curves shows that, from 168 days post-eruption and for the duration of the Xray supersoft source phase, two periods at 565 s and 3.57 h are detected. We suggest that these are the rotational period of the white dwarf and the orbital period of the binary, respectively, and that the system is likely to be an intermediate polar.The optical light-curve decline was very fast (t 2 2.9 d), suggesting that the white dwarf is likely massive ( 1.25 M ). The optical spectra obtained during the X-ray supersoft source phase exhibit narrow, complex, and moving emission lines of He ii, also characteristics of magnetic cataclysmic variables. The optical and X-ray data show evidence for accretion resumption while the X-ray supersoft source is still on, possibly extending its duration.

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Multimission observations of the old nova GK Per during the 2015 outburst

Cited by 16 publications

References 55 publications

Photoionization modelling of quiescence-phase spectra of novae and a symbiotic star

Photoionization modelling of quiescence-phase spectra of novae and a symbiotic star

Hard X-ray view on intermediate polars in theGaiaera

Multiwavelength observations of V407 Lupi (ASASSN-16kt) – a very fast nova erupting in an intermediate polar

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