Low-Level Nuclear Activity in Nearby Spiral Galaxies

@article{Ghosh2008LowLevelNA,
  title={Low-Level Nuclear Activity in Nearby Spiral Galaxies},
  author={Himel Ghosh and Smita Mathur and Fabrizio Fiore and Laura Ferrarese},
  journal={The Astrophysical Journal},
  year={2008},
  volume={687},
  pages={216 - 229}
}
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: (1) X-ray selection using the Chandra X-Ray Observatory, since X-rays are a ubiquitous feature of AGNs; (2) emphasis on late-type spiral and dwarf galaxies as the galaxies most likely to have low-mass SMBHs; (3) use of multiwavelength data to verify… 
A CENSUS OF X-RAY NUCLEAR ACTIVITY IN NEARBY GALAXIES
We have studied the X-ray nuclear activity of 187 nearby (distance less than 15 Mpc) galaxies observed with Chandra/ACIS. We found that 86 of them have a pointlike X-ray core, consistent with an
Discovery of Nuclear X-ray Sources in SINGS Galaxies
We present the results of a search for nuclear X-ray activity in nearby galaxies using Chandra archival data in a sample of 62 galaxies from the Spitzer Infrared Nearby Galaxy Survey. We detect 37
AMUSE-VIRGO. II. DOWN-SIZING IN BLACK HOLE ACCRETION
We complete the census of nuclear X-ray activity in 100 early-type Virgo galaxies observed by the Chandra X-ray Telescope as part of the AMUSE-Virgo survey, down to a (3σ) limiting luminosity of 3.7
BLACK HOLES IN BULGELESS GALAXIES: AN XMM-NEWTON INVESTIGATION OF NGC 3367 AND NGC 4536
The vast majority of optically identified active galactic nuclei (AGNs) in the local universe reside in host galaxies with prominent bulges, supporting the hypothesis that black hole formation and
THE INCIDENCE OF ACTIVE GALACTIC NUCLEI IN PURE DISK GALAXIES: THE SPITZER VIEW
Using the Spitzer telescope, we have conducted a high-resolution spectroscopic study of 18 bulgeless (Hubble type of Sd or Sdm) galaxies that show no definitive signatures of nuclear activity in
A Candidate Massive Black Hole in the Low-metallicity Dwarf Galaxy Pair Mrk 709
The incidence and properties of present-day dwarf galaxies hosting massive black holes (BHs) can provide important constraints on the origin of high-redshift BH seeds. Here we present high-resolution
A CHANDRA VIEW OF NGC 3621: A BULGELESS GALAXY HOSTING AN AGN IN ITS EARLY PHASE?
We report the detection of a weak X-ray point-source coincident with the nucleus of the bulgeless disk galaxy NGC 3621, recently discovered by Spitzer to display high-ionization mid-infrared lines
An X-ray Selected Sample of Candidate Black Holes in Dwarf Galaxies
We present a sample of hard X-ray-selected candidate black holes (BHs) in 19 dwarf galaxies. BH candidates are identified by cross-matching a parent sample of ∼44,000 local dwarf galaxies ( M ⋆ ≤ 3 ×
X-RAY NUCLEAR ACTIVITY IN S4G BARRED GALAXIES: NO LINK BETWEEN BAR STRENGTH AND CO-OCCURRENT SUPERMASSIVE BLACK HOLE FUELING
Stellar bars can lead to gas inflow toward the center of a galaxy and stimulate nuclear star formation. However, there is no compelling evidence on whether they also feed a central supermassive black
DISCOVERY OF A LARGE POPULATION OF ULTRALUMINOUS X-RAY SOURCES IN THE BULGELESS GALAXIES NGC 337 AND ESO 501-23
We have used Chandra observations of eight bulgeless disk galaxies to identify new ultraluminous X-ray source (ULX) candidates, study their high-mass X-ray binary (HMXB) population, and search for
...
...

References

SHOWING 1-10 OF 82 REFERENCES
Searching for hidden AGN in nearby star-forming galaxies with Chandra
Aims. We searched for X-ray signatures of AGN in a sample of star-forming, relatively early-type, nearby spiral galaxies, from the optical spectroscopic sample of Ho et al. The tight correlations
Three LINERs under the Chandra X-Ray Microscope
We use observations of three galaxies hosting low-ionization nuclear emission-line regions (LINERs; NGC 404, NGC 4736, and NGC 4579) with the Chandra X-Ray Observatory to study their power sources.
Accretion and Nuclear Activity of Quiescent Supermassive Black Holes. I. X-Ray Study
We have studied the nuclear activity in a sample of six quiescent early-type galaxies, with new Chandra data and archival HST optical images. Their nuclear sources have X-ray luminosities ~1038-1039
Classifying X-Ray Sources in External Galaxies from X-Ray Colors
The X-ray populations of Local Group galaxies have been classified in detail by Einstein, ROSAT, and ASCA, revealing a mix of binaries, supernova remnants (SNRs), and H II regions. However, these
A Search for Active Galactic Nuclei in Sc Galaxies with H II Spectra
We have searched for nuclear radio emission from a statistically complete sample of 40 Sc galaxies within 30 Mpc that are optically classified as star-forming objects, in order to determine whether
X-Ray Properties of Intermediate-Mass Black Holes in Active Galaxies
We present a pilot study of the X-ray properties of intermediate-mass (~105-106 M☉) black holes in active galaxies using the Chandra X-ray telescope. Eight of the 10 active galaxies are detected with
The Discovery of an Active Galactic Nucleus in the Late-Type Galaxy NGC 3621: Spitzer Spectroscopic Observations
We report the discovery of an active galactic nucleus (AGN) in the nearby SAd galaxy NGC 3621 using Spitzer high spectral resolution observations. These observations reveal the presence of [Ne V] 14
Identifying X-ray Sources in Bulge and Disk Galaxies
The X-ray populations of Local group galaxies have been classified in detail by Einstein, ROSAT and ASCA revealing a mix of binaries, supernova remnants and HII regions. However, these observatories
Chandra Snapshot Observations of Low-Luminosity Active Galactic Nuclei with a Compact Radio Source
The results of Chandra snapshot observations of 11 low-ionization nuclear emission-line regions (LINERs), three low-luminosity Seyfert galaxies, and one H II-LINER transition object are presented.
Accretion and Nuclear Activity of Quiescent Supermassive Black Holes. II. Optical Study and Interpretation
Our X-ray study of the nuclear activity in a new sample of six quiescent early-type galaxies, as well as in a larger sample from the literature, confirmed (Paper I) that the Bondi accretion rate of
...
...