تقرير
High Radio Frequency Properties and Variability of Brightest Cluster Galaxies
| العنوان: | High Radio Frequency Properties and Variability of Brightest Cluster Galaxies |
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| المؤلفون: | Hogan, M. T., Edge, A. C., Geach, J. E., Grainge, K. J. B., Hlavacek-Larrondo, J., Hovatta, T., Karim, A., McNamara, B. R., Rumsey, C., Russell, H. R., Salomé, P., Aller, H. D., Aller, M. F., Benford, D. J., Fabian, A. C., Readhead, A. C. S., Sadler, E. M., Saunders, R. D. E. |
| سنة النشر: | 2015 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | We consider the high radio frequency (15 GHz - 353 GHz) properties and variability of 35 Brightest Cluster Galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus allowing us to relate our results to the general population. We find that >6.0% of our parent sample (>15.1% if only cool-core clusters are considered) contain a radio-source at 150 GHz of at least 3mJy (~1x10^23 W/Hz at our median redshift of z~0.13). Furthermore, >3.4% of the BCGs in our parent sample contain a peaked component (Gigahertz Peaked Spectrum, GPS) in their spectra that peaks above 2 GHz, increasing to >8.5% if only cool-core clusters are considered. We see little evidence for strong variability at 15 GHz on short (week-month) time-scales although we see variations greater than 20% at 150 GHz over 6-month times-frames for 4 of the 23 sources with multi-epoch observations. Much more prevalent is long-term (year-decade time-scale) variability, with average annual amplitude variations greater than 1% at 15 GHz being commonplace. There is a weak trend towards higher variability as the peak of the GPS-like component occurs at higher frequency. We demonstrate the complexity that is seen in the radio spectra of BCGs and discuss the potentially significant implications of these high-peaking components for Sunyaev-Zel'dovich cluster searches. Comment: 20 pages (+15 pages of Appendices), 16 figures (of which 6 in Appendices), 5 tables (of which 4 in Appendices). Accepted for publication in MNRAS |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1093/mnras/stv1518 |
| URL الوصول: | http://arxiv.org/abs/1507.03022 |
| رقم الأكسشن: | edsarx.1507.03022 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1093/mnras/stv1518 |
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