Subparsec - scale HI in the nucleus of NGC 4151
نویسندگان
چکیده
We present sensitive, high-resolution λ21-cm VLBA+VLA observations of the radio jet and nuclear HI absorption in NGC 4151. The 25-mas (1.6-pc) resolution continuum image reveals a highly collimated radio jet, underlying the discrete components seen previously with MER-LIN and the VLA. Spatially and kinematically complex HI absorption is detected against the whole 3-pc extent of the continuum component predicted by Ulvestad et al. to contain the AGN. Instead, we suggest the component against which the absorption is detected is part of the eastern counterjet, ruling it out as the location for the AGN.
منابع مشابه
Iron K features in the hard X - ray XMM - Newton spectrum of NGC 4151
Recent XMM-Newton observations have measured the hard (2.5-12 keV) X-ray spectrum of the well-known Seyfert galaxy NGC 4151 with a signal-to-noise unprecedented for this source. We find that a spectral model, developed to fit previous Bep-poSAX and ASCA observations of NGC 4151, provides an excellent description of the XMM-Newton EPIC data. The results support the view that it is the level of t...
متن کاملar X iv : a st ro - p h / 98 09 09 0 v 1 8 S ep 1 99 8 Infrared spectroscopy of NGC 4151 : ISO observations and NLR line profiles
We present ISO-SWS and ISOPHOT-S spectroscopy 4 of the Seyfert galaxy NGC 4151. We detect a total of 17 fine-structure emission lines emitted by a wide range of low-and high-excitation ions, two rotational lines of molecular hydrogen, and the Brβ HI line. We find that the mid-IR fine-structure line profiles display blue asymmetries which are very similar to those observed in the optical lines p...
متن کاملNGC 4151 – A unified active galactic nucleus
We present a unified picture of active galactic nuclei which we construct from a detailed model of line emission in the active source in NGC 4151. This source provides us with an opportunity to explore the variation of structure with luminosity in an object which, in the model, derives its unusual properties as a consequence of the angle of the accretion disc to the line of sight. The key featu...
متن کاملThe complex soft X - ray spectrum of NGC 4151
We present a detailed analysis of the complex soft X-ray spectrum of NGC 4151 measured by the RGS instruments aboard XMM-Newton. The XMM-Newton RGS spectra demonstrate that the soft X-ray emission is extremely rich in X-ray emission lines and radiative recombination continua (RRC), with no clear evidence for any underlying continuum emission. Line emission, and the associated RRC, are clearly d...
متن کاملCharacterising the complex absorber in NGC 4151
We present a detailed analysis of the complex absorption apparent in the 2–6 keV X-ray spectrum of the bright nearby Seyfert galaxy NGC 4151. We first utilize the large bandpass and medium spectral resolution afforded by BeppoSAX data to construct a 1–100 keV spectral template, which assumes the absorption arises in both warm (i.e. partially photoionized) and cold gas present in the line of sig...
متن کامل