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تسجيل مستخدم جديدIntermittent jet activity in the radio galaxy 4C29.30?
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تأليف
M. Jamrozy
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We present radio observations at frequencies ranging from 240 to 8460 MHz of the radio galaxy 4C29.30 (J0840+2949) using the Giant Metrewave Radio Telescope (GMRT), the Very Large Array (VLA) and the Effelsberg telescope. We report the existence of weak extended emission with an angular size of $sim$520 arcsec (639 kpc) within which a compact edge-brightened double-lobed source with a size of 29 arcsec (36 kpc) is embedded. We determine the spectrum of the inner double from 240 to 8460 MHz and show that it has a single power-law spectrum with a spectral index of $sim$0.8. Its spectral age is estimated to be $lapp$33 Myr. The extended diffuse emission has a steep spectrum with a spectral index of $sim$1.3 and a break frequency $lapp$240 MHz. The spectral age is $gapp$200 Myr, suggesting that the extended diffuse emission is due to an earlier cycle of activity. We reanalyse archival x-ray data from Chandra and suggest that the x-ray emission from the hotspots consists of a mixture of nonthermal and thermal components, the latter being possibly due to gas which is shock heated by the jets from the host galaxy.
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We report the results of our observations of HI absorption towards the central region of the rejuvenated radio galaxy 4C29.30 (J0840+2949) with the Giant Metrewave Radio Telescope (GMRT). The radio source has diffuse, extended emission with an angula
r size of $sim$520 arcsec (639 kpc) within which a compact edge-brightened double-lobed source with a size of 29 arcsec (36 kpc) is embedded. The absorption profile which is seen towards the central component of the inner double is well resolved and consists of six components; all but one of which appears to be red-shifted relative to the optical systemic velocity. The neutral hydrogen column density is estimated to be $N$(HI)=4.7$times10^{21}$($T_s$/100)($f_c$/1.0) cm$^{-2}$, where $T_s$ and $f_c$ are the spin temperature and covering factor of the background source respectively. This detection reinforces a strong correlation between the occurrence of HI absorption and rejuvenation of radio activity suggested earlier, with the possibility that the red-shifted gas is fuelling the recent activity.
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