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http://hdl.handle.net/2289/6691Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Misra, Ranjeev | - |
| dc.contributor.author | Yadav, J.S. | - |
| dc.contributor.author | Paul, Biswajit | - |
| dc.contributor.author | +10 Co-authors | - |
| dc.date.accessioned | 2017-08-03T11:03:13Z | - |
| dc.date.available | 2017-08-03T11:03:13Z | - |
| dc.date.issued | 2017-02 | - |
| dc.identifier.citation | Astrophysical Journal, 2017, Vol. 835, p 195 | en_US |
| dc.identifier.issn | 0004-637X | - |
| dc.identifier.issn | 1538-4357-(Online) | - |
| dc.identifier.uri | http://hdl.handle.net/2289/6691 | - |
| dc.description | Open Access | en_US |
| dc.description.abstract | We report the first analysis of data from AstroSat/LAXPC observations of Cygnus X-1 in 2016 January. LAXPC spectra reveals that the source was in the canonical hard state, represented by a prominent thermal Comptonization component having a photon index of ~1.8 and high temperature of kTe > 60 keV along with weak reflection and possible disk emission. The power spectrum can be characterized by two broad lorentzian functions centered at ~0.4 and ~3 Hz. The rms of the low-frequency component decreases from ~15% at around 4 keV to ~10% at around 50 keV, while that of the high-frequency one varies less rapidly from ~13.5% to ~11.5% in the same energy range. The time lag between the hard (20–40 keV) and soft (5–10 keV) bands varies in a step-like manner being nearly constant at ~50 milliseconds from 0.3 to 0.9 Hz, decreasing to ~8 milliseconds from 2 to 5 Hz and finally dropping to ~2 milliseconds for higher frequencies. The time lags increase with energy for both the low and high-frequency components. The event mode LAXPC data allows for flux resolved spectral analysis on a timescale of 1 s, which clearly shows that the photon index increased from ~1.72 to ~1.80 as the flux increased by nearly a factor of two. We discuss the results in the framework of the fluctuation propagation model. | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | IOP Sciences for The American Astronomical Society | en_US |
| dc.relation.uri | http://adsabs.harvard.edu/abs/2017ApJ...835..195M | en_US |
| dc.relation.uri | https://arxiv.org/abs/1612.08793 | en_US |
| dc.relation.uri | http://dx.doi.org/ 10.3847/1538-4357/835/2/195 | en_US |
| dc.rights | 2017, The American Astronomical Society. | en_US |
| dc.title | AstroSat/LAXPC Observation of Cygnus X-1 in the Hard State. | en_US |
| dc.type | Article | en_US |
| Appears in Collections: | Research Papers (A&A) | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 2017_AstrophyJournal_835_195.pdf | Oopen Access | 473.33 kB | Adobe PDF | View/Open |
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