Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-13T02:37:18.417Z Has data issue: false hasContentIssue false

Cosmic rays and high energy emission from starburst galaxies

Published online by Cambridge University Press:  17 August 2012

Brian C. Lacki
Affiliation:
Jansky Fellow & Institute for Advanced Study; Einstein Drive, Princeton, NJ 08540, USA email: brianlacki@ias.edu
Todd A. Thompson
Affiliation:
Department of Astronomy and Center for Cosmology and AstroParticle Physics, Ohio State University; 140 W. 18th Ave, Columbus, OH 43210, USA
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The nearby starburst galaxies M82 and NGC 253 are now detected in GeV and TeV γ-rays, allowing us to directly study cosmic rays (CRs) in starburst galaxies. Combined with radio observations, the detections constrain the propagation and density of CRs in these starbursts. We discuss the implications for “proton calorimetry”, whether CR protons cool through pion losses before escaping these galaxies. The ratio of γ-ray and radio luminosities constrains how much of the CR electron cooling is due to synchrotron losses. As for leptonic emission, we predict that synchrotron and Inverse Compton emission make up ~1–10% of the unresolved hard X-ray emission from M82, and a few percent or less of the total X-ray emission from starbursts. A detection of these components would inform us of the magnetic field strength and 10 – 100 TeV electron spectrum. We conclude by discussing the prospects for detecting leptonic MeV γ-rays from starbursts and the cosmic γ-ray background.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2012

References

Abdo, A. A., Ackermann, M., Ajello, M., et al. 2010, ApJL, 709, L152.CrossRefGoogle Scholar
Acciari, V. A., Aliu, E., Arlen, T., et al. 2009, Nature, 462, 770Google Scholar
Acero, F., Aharonian, F., Akhperjanian, A. G., et al. 2009, Science, 326, 1080CrossRefGoogle Scholar
Aharonian, F. A., Atoyan, A. M., & Nagapetyan, A. M. 1983, Astrophysics, 19, 187Google Scholar
Aharonian, F. A. & Atoyan, A. M. 2000, A&A, 362, 937Google Scholar
Akyuz, A., Brouillet, N., & Ozel, M. E. 1991, A&A, 248, 419Google Scholar
Cappi, M., Persic, M., Bassani, L., et al. 1999, A&A, 350, 777Google Scholar
Crocker, R. M., Jones, D. I., Melia, F., Ott, J., & Protheroe, R. J. 2010, Nature, 463, 65CrossRefGoogle Scholar
de Cea del Pozo, E., Torres, D. F., Rodriguez, A. Y., & Reimer, O. 2009, arXiv:0912.3497Google Scholar
Hargrave, P. J. 1974, MNRAS, 168, 491CrossRefGoogle Scholar
Kellermann, K. I., Pauliny-Toth, I. I. K., & Williams, P. J. S. 1969, ApJ, 157, 1CrossRefGoogle Scholar
Lacki, B. C., Thompson, T. A., & Quataert, E. 2010, ApJ, 717, 1CrossRefGoogle Scholar
Lacki, B. C. & Thompson, T. A. 2010a, ApJ, 717, 196CrossRefGoogle Scholar
Lacki, B. C. & Thompson, T. A. 2010b, arXiv:1010.3030Google Scholar
Lacki, B. C., Thompson, T. A., Quataert, E., Loeb, A., & Waxman, E. 2011, ApJ, 734, 107CrossRefGoogle Scholar
Pavlidou, V. & Fields, B. D. 2002, ApJL, 575, L5.CrossRefGoogle Scholar
Persic, M., Rephaeli, Y., Braito, V., et al. 2004, A&A, 419, 849Google Scholar
Persic, M. & Rephaeli, Y. 2010, MNRAS, 403, 1569CrossRefGoogle Scholar
Protheroe, R. J. & Wolfendale, A. W. 1980, A&A, 92, 175Google Scholar
Robishaw, T., Quataert, E., & Heiles, C. 2008, ApJ, 680, 981CrossRefGoogle Scholar
Strickland, D. K. & Heckman, T. M. 2007, ApJ, 658, 258CrossRefGoogle Scholar
Strong, A. W., Porter, T. A., Digel, S. W., et al. 2010, ApJL, 722, L58.CrossRefGoogle Scholar
Thompson, T. A., et al. 2006, ApJ, 645, 186CrossRefGoogle Scholar
Thompson, T. A., Quataert, E., & Waxman, E. 2007, ApJ, 654, 219CrossRefGoogle Scholar
Torres, D. F. 2004, ApJ, 617, 966CrossRefGoogle Scholar
Völk, H. J. 1989, A&A, 218, 67Google Scholar