ar X iv : a st ro - p h / 02 08 26 2 v 1 1 3 A ug 2 00 2 Balmer and He I absorption in the nuclear spectrum of NGC 4151
نویسندگان
چکیده
Spectra taken with the Space Telescope Imaging Spectrograph (STIS) allow accurate location and extraction of the nuclear spectrum of NGC 4151, with minimal contamination by extended line emission and circumnuclear starlight. Spectra since 1997 show that the P Cygni Balmer and He I absorption seen previously in low nuclear states, is present in higher states, with outflow velocity that changes with the nuclear flux. The phenomenon is discussed in terms of some of the absorbers seen in the UV resonance lines, and outflows from the central source and surrounding torus.
منابع مشابه
ar X iv : a st ro - p h / 02 02 09 3 v 1 5 F eb 2 00 2 1 IRON FEATURES IN THE XMM - NEWTON SPECTRUM OF NGC 4151
We present a detailed analysis of the hard X-ray (>2.5 keV) EPIC spectra from the first observations of NGC 4151 made by XMM-Newton. We fit the spectra with a model consisting of a power-law continuum modified by line-of-sight absorption (arising in both partially pho-toionized and neutral gas) plus additional iron-K emission and absorption features. This model provides an excellent overall fit...
متن کاملar X iv : a st ro - p h / 99 08 13 7 v 1 1 2 A ug 1 99 9 HIGH VELOCITY LINE EMISSION IN THE NLR OF NGC 4151
Narrow-band imaging of the nuclear region of NGC 4151 with the Hubble Space Telescope is presented. The filter bandpasses isolate line emission in various high velocity ranges in several ions. Slitless and long-slit spectra of the region with the Space Telescope Imaging Spectrograph also indicate the locations of high velocity gas. These emission regions are faint and are interspersed among the...
متن کاملar X iv : a st ro - p h / 01 08 50 0 v 1 3 1 A ug 2 00 1 BeppoSAX Observation of NGC 3079
Using the BeppoSAX observatory, we have observed a nearby LINER/Seyfert 2 galaxy, NGC 3079, which is known as an outflow galaxy and a bright H2O-maser source. Using the PDS detector, we have revealed that the NGC 3079 nucleus suffers from a Compton-thick absorption, with a hydrogen column density ∼ 10 cm. After corrected the absorption, the 2–10 keV luminosity becomes 10 erg s at a distance of ...
متن کاملar X iv : a st ro - p h / 02 08 30 1 v 1 1 5 A ug 2 00 2 Measurement of the Spectrum of UHE Cosmic Rays by the FADC Detector of the HiRes Experiment
Preprint submitted to Elsevier Preprint 17 February 2008 We have measured the spectrum of UHE cosmic rays using the flash ADC (FADC) detector (called HiRes-II) of the High Resolution Fly’s Eye experiment running in monocular mode. We describe in detail the data analysis, development of the Monte Carlo simulation program, and results. We also describe the results of our other detector, HiRes-I. ...
متن کامل