CHANDRAOBSERVATIONS OF 1RXS J141256.0+792204 (CALVERA)
| Autor: | Andrew S. H. Shevchuk, Robert E. Rutledge, Derek B. Fox |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics 010308 nuclear & particles physics FOS: Physical sciences Astronomy and Astrophysics Radius Astrophysics Compact star Astrophysics - Astrophysics of Galaxies 01 natural sciences Spectral line Stars Neutron star Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences ROSAT Emission spectrum Astrophysics - High Energy Astrophysical Phenomena 010303 astronomy & astrophysics Equivalent width |
| Zdroj: | The Astrophysical Journal. 705:391-397 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1088/0004-637x/705/1/391 |
| Popis: | We report the results of a 30 ks Chandra ACIS-S observation of the isolated compact object 1RXS J141256.0+792204 (Calvera). The X-ray spectrum is adequately described by an absorbed neutron star hydrogen atmosphere model with an effective temperature at infinity of 88.3 +/- 0.8 eV and radiation radius at infinity of 4.1 +/- 0.1 km/kpc. The best-fit blackbody spectrum yields parameters consistent with previous measurements; although the fit itself is not statistically acceptable, systematic uncertainties in the pile-up correction may contribute to this. We find marginal evidence for narrow spectral features in the X-ray spectrum between 0.3 and 1.0 keV. In one interpretation, we find evidence at 81%-confidence for an absorption edge at 0.64 (+0.08) (-0.06) keV with an equivalent width of ~70 eV; if this feature is real, it is reminiscent of features seen in the isolated neutron stars RX J1605.3+3249, RX J0720.4-3125, and 1RXS J130848.6+212708 (RBS 1223). In an alternative approach, we find evidence at 88%-confidence for an unresolved emission line at energy 0.53 +/- 0.02 keV, with an equivalent width of ~28 eV; the interpretation of this feature, if real, is uncertain. We search for coherent pulsations up to the Nyquist frequency of 1.13 Hz and set an upper limit of 8.0% rms on the strength of any such modulation. We derive an improved position for the source and set the most rigorous limits to-date on any associated extended emission on arcsecond scales. Our analysis confirms the basic picture of Calvera as the first isolated compact object in the ROSAT/Bright Source Catalog discovered in six years, the hottest such object known, and an intriguing target for multiwavelength study. Comment: Submitted to ApJ. AASTeX, 19 pages, 2 figures |
| Databáze: | OpenAIRE |
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