The Soft Gamma-Ray Spectral Variability of Cygnus X-1. McConnell, M. L., Zdziarski, A. A., Bennett, K., Bloemen, H., Collmar, W., Hermsen, W., Kuiper, L., Paciesas, W., Phlips, B. F., Poutanen, J., Ryan, J. M., Schönfelder, V., Steinle, H., & Strong, A. W. The Astrophysical Journal, 572:984–995, June, 2002. ADS Bibcode: 2002ApJ...572..984M![The Soft Gamma-Ray Spectral Variability of Cygnus X-1 [link]](https://bibbase.org/img/filetypes/link.svg "link")
Paper doi abstract bibtex We have used observations of Cyg X-1 from the Compton Gamma Ray Observatory and BeppoSAX to study the variation in the MeV γ-ray emission between the hard and soft spectral states, using spectra that cover the energy range from 20 keV up to 10 MeV. These data provide evidence for significant spectral variability at energies above 1 MeV. In particular, whereas the hard X-ray flux decreases during the soft state, the flux at energies above 1 MeV increases, resulting in a significantly harder γ-ray spectrum at energies above 1 MeV. This behavior is consistent with the general picture of galactic black hole candidates having two distinct spectral forms at soft γ-ray energies. These data extend this picture, for the first time, to energies above 1 MeV. We have used two different hybrid thermal/nonthermal Comptonization models to fit broadband spectral data obtained in both the hard and soft spectral states. These fits provide a quantitative estimate of the electron distribution and allow us to probe the physical changes that take place during transitions between the low and high X-ray states. We find that there is a significant increase (by a factor of ~4) in the bolometric luminosity as the source moves from the hard state to the soft state. Furthermore, the presence of a nonthermal tail in the Comptonizing electron distribution provides significant constraints on the magnetic field in the source region.
@article{mcconnellSoftGammaRaySpectral2002,
title = {The {Soft} {Gamma}-{Ray} {Spectral} {Variability} of {Cygnus} {X}-1},
volume = {572},
issn = {0004-637X},
url = {https://ui.adsabs.harvard.edu/abs/2002ApJ...572..984M},
doi = {10.1086/340436},
abstract = {We have used observations of Cyg X-1 from the Compton Gamma Ray Observatory and BeppoSAX to study the variation in the MeV γ-ray emission between the hard and soft spectral states, using spectra that cover the energy range from 20 keV up to 10 MeV. These data provide evidence for significant spectral variability at energies above 1 MeV. In particular, whereas the hard X-ray flux decreases during the soft state, the flux at energies above 1 MeV increases, resulting in a significantly harder γ-ray spectrum at energies above 1 MeV. This behavior is consistent with the general picture of galactic black hole candidates having two distinct spectral forms at soft γ-ray energies. These data extend this picture, for the first time, to energies above 1 MeV. We have used two different hybrid thermal/nonthermal Comptonization models to fit broadband spectral data obtained in both the hard and soft spectral states. These fits provide a quantitative estimate of the electron distribution and allow us to probe the physical changes that take place during transitions between the low and high X-ray states. We find that there is a significant increase (by a factor of {\textasciitilde}4) in the bolometric luminosity as the source moves from the hard state to the soft state. Furthermore, the presence of a nonthermal tail in the Comptonizing electron distribution provides significant constraints on the magnetic field in the source region.},
urldate = {2022-12-30},
journal = {The Astrophysical Journal},
author = {McConnell, M. L. and Zdziarski, A. A. and Bennett, K. and Bloemen, H. and Collmar, W. and Hermsen, W. and Kuiper, L. and Paciesas, W. and Phlips, B. F. and Poutanen, J. and Ryan, J. M. and Schönfelder, V. and Steinle, H. and Strong, A. W.},
month = jun,
year = {2002},
note = {ADS Bibcode: 2002ApJ...572..984M},
keywords = {Accretion, Accretion Disks, Astrophysics, Black Hole Physics, Gamma Rays: Observations, Stars: Individual: Constellation Name: Cygnus X-1, X-Rays: Stars},
pages = {984--995},
}
Downloads: 0
{"_id":"hn55kMEvSeo7bNmMX","bibbaseid":"mcconnell-zdziarski-bennett-bloemen-collmar-hermsen-kuiper-paciesas-etal-thesoftgammarayspectralvariabilityofcygnusx1-2002","author_short":["McConnell, M. L.","Zdziarski, A. A.","Bennett, K.","Bloemen, H.","Collmar, W.","Hermsen, W.","Kuiper, L.","Paciesas, W.","Phlips, B. F.","Poutanen, J.","Ryan, J. M.","Schönfelder, V.","Steinle, H.","Strong, A. W."],"bibdata":{"bibtype":"article","type":"article","title":"The Soft Gamma-Ray Spectral Variability of Cygnus X-1","volume":"572","issn":"0004-637X","url":"https://ui.adsabs.harvard.edu/abs/2002ApJ...572..984M","doi":"10.1086/340436","abstract":"We have used observations of Cyg X-1 from the Compton Gamma Ray Observatory and BeppoSAX to study the variation in the MeV γ-ray emission between the hard and soft spectral states, using spectra that cover the energy range from 20 keV up to 10 MeV. These data provide evidence for significant spectral variability at energies above 1 MeV. In particular, whereas the hard X-ray flux decreases during the soft state, the flux at energies above 1 MeV increases, resulting in a significantly harder γ-ray spectrum at energies above 1 MeV. This behavior is consistent with the general picture of galactic black hole candidates having two distinct spectral forms at soft γ-ray energies. These data extend this picture, for the first time, to energies above 1 MeV. We have used two different hybrid thermal/nonthermal Comptonization models to fit broadband spectral data obtained in both the hard and soft spectral states. These fits provide a quantitative estimate of the electron distribution and allow us to probe the physical changes that take place during transitions between the low and high X-ray states. We find that there is a significant increase (by a factor of ~4) in the bolometric luminosity as the source moves from the hard state to the soft state. Furthermore, the presence of a nonthermal tail in the Comptonizing electron distribution provides significant constraints on the magnetic field in the source region.","urldate":"2022-12-30","journal":"The Astrophysical Journal","author":[{"propositions":[],"lastnames":["McConnell"],"firstnames":["M.","L."],"suffixes":[]},{"propositions":[],"lastnames":["Zdziarski"],"firstnames":["A.","A."],"suffixes":[]},{"propositions":[],"lastnames":["Bennett"],"firstnames":["K."],"suffixes":[]},{"propositions":[],"lastnames":["Bloemen"],"firstnames":["H."],"suffixes":[]},{"propositions":[],"lastnames":["Collmar"],"firstnames":["W."],"suffixes":[]},{"propositions":[],"lastnames":["Hermsen"],"firstnames":["W."],"suffixes":[]},{"propositions":[],"lastnames":["Kuiper"],"firstnames":["L."],"suffixes":[]},{"propositions":[],"lastnames":["Paciesas"],"firstnames":["W."],"suffixes":[]},{"propositions":[],"lastnames":["Phlips"],"firstnames":["B.","F."],"suffixes":[]},{"propositions":[],"lastnames":["Poutanen"],"firstnames":["J."],"suffixes":[]},{"propositions":[],"lastnames":["Ryan"],"firstnames":["J.","M."],"suffixes":[]},{"propositions":[],"lastnames":["Schönfelder"],"firstnames":["V."],"suffixes":[]},{"propositions":[],"lastnames":["Steinle"],"firstnames":["H."],"suffixes":[]},{"propositions":[],"lastnames":["Strong"],"firstnames":["A.","W."],"suffixes":[]}],"month":"June","year":"2002","note":"ADS Bibcode: 2002ApJ...572..984M","keywords":"Accretion, Accretion Disks, Astrophysics, Black Hole Physics, Gamma Rays: Observations, Stars: Individual: Constellation Name: Cygnus X-1, X-Rays: Stars","pages":"984–995","bibtex":"@article{mcconnellSoftGammaRaySpectral2002,\n\ttitle = {The {Soft} {Gamma}-{Ray} {Spectral} {Variability} of {Cygnus} {X}-1},\n\tvolume = {572},\n\tissn = {0004-637X},\n\turl = {https://ui.adsabs.harvard.edu/abs/2002ApJ...572..984M},\n\tdoi = {10.1086/340436},\n\tabstract = {We have used observations of Cyg X-1 from the Compton Gamma Ray Observatory and BeppoSAX to study the variation in the MeV γ-ray emission between the hard and soft spectral states, using spectra that cover the energy range from 20 keV up to 10 MeV. These data provide evidence for significant spectral variability at energies above 1 MeV. In particular, whereas the hard X-ray flux decreases during the soft state, the flux at energies above 1 MeV increases, resulting in a significantly harder γ-ray spectrum at energies above 1 MeV. This behavior is consistent with the general picture of galactic black hole candidates having two distinct spectral forms at soft γ-ray energies. These data extend this picture, for the first time, to energies above 1 MeV. We have used two different hybrid thermal/nonthermal Comptonization models to fit broadband spectral data obtained in both the hard and soft spectral states. These fits provide a quantitative estimate of the electron distribution and allow us to probe the physical changes that take place during transitions between the low and high X-ray states. We find that there is a significant increase (by a factor of {\\textasciitilde}4) in the bolometric luminosity as the source moves from the hard state to the soft state. Furthermore, the presence of a nonthermal tail in the Comptonizing electron distribution provides significant constraints on the magnetic field in the source region.},\n\turldate = {2022-12-30},\n\tjournal = {The Astrophysical Journal},\n\tauthor = {McConnell, M. L. and Zdziarski, A. A. and Bennett, K. and Bloemen, H. and Collmar, W. and Hermsen, W. and Kuiper, L. and Paciesas, W. and Phlips, B. F. and Poutanen, J. and Ryan, J. M. and Schönfelder, V. and Steinle, H. and Strong, A. W.},\n\tmonth = jun,\n\tyear = {2002},\n\tnote = {ADS Bibcode: 2002ApJ...572..984M},\n\tkeywords = {Accretion, Accretion Disks, Astrophysics, Black Hole Physics, Gamma Rays: Observations, Stars: Individual: Constellation Name: Cygnus X-1, X-Rays: Stars},\n\tpages = {984--995},\n}\n\n","author_short":["McConnell, M. L.","Zdziarski, A. A.","Bennett, K.","Bloemen, H.","Collmar, W.","Hermsen, W.","Kuiper, L.","Paciesas, W.","Phlips, B. F.","Poutanen, J.","Ryan, J. M.","Schönfelder, V.","Steinle, H.","Strong, A. W."],"key":"mcconnellSoftGammaRaySpectral2002","id":"mcconnellSoftGammaRaySpectral2002","bibbaseid":"mcconnell-zdziarski-bennett-bloemen-collmar-hermsen-kuiper-paciesas-etal-thesoftgammarayspectralvariabilityofcygnusx1-2002","role":"author","urls":{"Paper":"https://ui.adsabs.harvard.edu/abs/2002ApJ...572..984M"},"keyword":["Accretion","Accretion Disks","Astrophysics","Black Hole Physics","Gamma Rays: Observations","Stars: Individual: Constellation Name: Cygnus X-1","X-Rays: Stars"],"metadata":{"authorlinks":{}},"html":""},"bibtype":"article","biburl":"https://bibbase.org/zotero/valepeirano","dataSources":["ftqMNtyNjLWewoxW9"],"keywords":["accretion","accretion disks","astrophysics","black hole physics","gamma rays: observations","stars: individual: constellation name: cygnus x-1","x-rays: stars"],"search_terms":["soft","gamma","ray","spectral","variability","cygnus","mcconnell","zdziarski","bennett","bloemen","collmar","hermsen","kuiper","paciesas","phlips","poutanen","ryan","schönfelder","steinle","strong"],"title":"The Soft Gamma-Ray Spectral Variability of Cygnus X-1","year":2002}