| Name | OT1_frahoui_1 |
| Title | Investigating the origin of the far-infrared emission of the microquasar Cygnus X-1 |
| URL | http://archives.esac.esa.int/hsa/whsa-tap-server/data?retrieval_type=OBSERVATION&observation_id=1342257161&instrument_name=PACS&product_level=LEVEL0&compress=true |
| DOI | https://doi.org/10.5270/esa-zjeggnn |
| Author | rahoui, f. |
| Description | Microquasars are Galactic X-ray binaries exhibiting collimated outflows commonly called jets. In particular, the so-called compact jets are detected almost simultaneously in all the spectral domains, and are characterised by the existence of a spectral break at which they change their emission regime from optically thick to optically thin synchrotron. The determination of this cut-off frequency is fundamental for the understanding of the accretion-ejection processes as it is related to the black hole spin and mass, as well as to the accretion rate. In a previous Spitzer spectroscopic study of Cygnus X-1, we assessed the contribution of the compact jets to the mid-infrared continuum as well as their spectral break. Nevertheless, its accurate value appears to be dependent on the model used to describe the continuum of the companion star, which is the blue supergiant HD226868. Indeed, it changes whether we consider bremsstrahlung from the stellar winds or thermal emission from a circumstellar dust component. We therefore require photometric observations of Cygnus X-1 with PACS, in the blue, green, and red filters, in order to assess the flux density level of the source at 70, 100, and 160 microns. These measurements, combined with our Spitzer spectra, will allow us to discriminate between bremsstrahlung and dust, which will eventually lead us to the accurate determination of the spectral break of the compact jets exhibited by Cygnus X-1. |
| Publication | |
| Instrument | PACS_PacsPhoto_largeScan |
| Temporal Coverage | 2012-12-13T14:12:42Z/2012-12-13T20:07:28Z |
| Version | SPG v14.2.0 |
| Mission Description | Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities. |
| Creator Contact | https://support.cosmos.esa.int/h®erschel/ |
| Date Published | 2013-06-13T19:26:54Z |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, rahoui, f., 2013, OT1_frahoui_1, SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-zjeggnn |