Low‐Level Nuclear Activity in Nearby Spiral Galaxies
نویسندگان
چکیده
منابع مشابه
Low-Level Nuclear Activity in Nearby Spiral Galaxies
We are conducting a search for supermassive black holes (SMBHs) with masses below ∼107 M⊙ by looking for signs of extremely low-level nuclear activity in nearby galaxies that are not known to be AGNs. Our survey has the following characteristics: (a) X-ray selection using the Chandra X-ray Observatory, since x-rays are a ubiquitous feature of AGNs; (b) Emphasis on late-type spiral and dwarf gal...
متن کاملNuclear Activity in Nearby Galaxies
A significant fraction of nearby galaxies show evidence of weak nuclear activity unrelated to normal stellar processes. Recent high-resolution, multiwavelength observations indicate that the bulk of this activity derives from black hole accretion with a wide range of accretion rates. The low accretion rates that typify most low-luminosity active galactic nuclei induce significant modifications ...
متن کاملA census of X-ray nuclear activity in nearby galaxies
We have studied the X-ray nuclear activity of 187 nearby (distance < 15 Mpc) galaxies observed with Chandra/ACIS. We found that 86 of them have a point-like X-ray core, consistent with an accreting BH. We argue that the majority of them are nuclear BHs, rather than X-ray binaries. The fraction of galaxies with an X-ray detected nuclear BH is higher (≈ 60 per cent) for ellipticals and early-type...
متن کاملA Radio Census of Nuclear Activity in Nearby Galaxies
In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, as manifested by their radio emission, we have carried out a high-resolution Multi-Element Radio-Linked Interferometer Network (MERLIN) survey of LINERs and composite LINER/Hii galaxies from a complete magnitude-limited sample of bright nearby galaxies (Palomar sample) with unknown arcsecond-...
متن کاملAccretion of gas onto nearby spiral galaxies
We present evidence for cosmological gas accretion onto spiral galaxies in the local universe. The accretion is seen through its effects on the dynamics of the extra-planar neutral gas. The accretion rates that we estimate for two nearby spiral galaxies are of the order of their star formation rates. Our model shows that most of the extra-planar gas is produced by supernova feedback (galactic f...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2008
ISSN: 0004-637X,1538-4357
DOI: 10.1086/591508