Bibcode
Gandhi, P.; Gallo, E.; Fender, R. P.; Cantrell, A. G.; Chatterjee, R.; Casella, P.; Markoff, S.; Russell, D. M.; Shahbaz, T.; O'Brien, K.; Miller-Jones, J. C. A.; Maitra, D.; Homan, J.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 429, Issue 1, p.815-832
Fecha de publicación:
2
2013
Número de citas
107
Número de citas referidas
99
Descripción
In X-ray binaries, compact jets are known to commonly radiate at radio
to infrared frequencies, whereas at optical to γ-ray energies, the
contribution of the jet is debated. The total luminosity, and hence
power of the jet, is critically dependent on the position of the break
in its spectrum, between optically thick (self-absorbed) and optically
thin synchrotron emission. This break, or turnover, has been reported in
just one black hole X-ray binary (BHXB) thus far, GX 339-4, and inferred
via spectral fitting in two others, A0620-00 and Cyg X-1. Here, we
collect a wealth of multi-wavelength data from the outbursts of BHXBs
during hard X-ray states, in order to search for jet breaks as yet
unidentified in their spectral energy distributions. In particular, we
report the direct detection of the jet break in the spectrum of V404 Cyg
during its 1989 outburst, at νb = (1.8 ± 0.3)
× 1014 Hz (1.7 ± 0.2 μm). We increase the
number of BHXBs with measured jet breaks from three to eight. Jet breaks
are found at frequencies spanning more than two orders of magnitude,
from νb = (4.5 ± 0.8) × 1012 Hz
for XTE J1118+480 during its 2005 outburst, to νb > 4.7
× 1014 Hz for V4641 Sgr in outburst. A positive
correlation between jet break frequency and luminosity is expected
theoretically; νb∝L˜ 0.5ν,
jet if other parameters are constant. With constraints on the jet
break in a total of 12 BHXBs including two quiescent systems, we find a
large range of jet break frequencies at similar luminosities and no
obvious global relation (but such a relation cannot be ruled out for
individual sources). We speculate that different magnetic field
strengths and/or different radii of the acceleration zone in the inner
regions of the jet are likely to be responsible for the observed scatter
between sources. There is evidence that the high-energy cooling break in
the jet spectrum shifts from UV energies at LX ˜
10-8LEdd (implying the jet may dominate the X-ray
emission in quiescence) to X-ray energies at
˜10-3LEdd. Finally, we find that the jet
break luminosity scales as Lν, jet∝L0.56
± 0.05X (very similar to the radio-X-ray
correlation), and radio-faint BHXBs have fainter jet breaks. In
quiescence the jet break luminosity exceeds the X-ray luminosity.
Proyectos relacionados
Agujeros negros, estrellas de neutrones, enanas blancas y su entorno local
Los agujeros negros y estrellas de neutrones en binarias de rayos-X son laboratorios únicos para explorar la física de estos objetos compactos. No solo permiten confirmar la existencia de agujeros negros de origen estelar a través de mediciones dinámicas de sus masas, sino que también permiten investigar el comportamiento de la materia y la
Montserrat
Armas Padilla