Related papers: Chandra unveils a binary Active Galactic Nucleus i…
We present broadband and narrowband Hubble Space Telescope images of the central region of the heavily disturbed Virgo cluster galaxy NGC 4438 (Arp120), whose nucleus has been described as a type 1 LINER or dwarf Seyfert. Narrowband H-alpha…
We report the discovery of a kiloparsec-scale dual active galactic nucleus (AGN) in J0038+4128. From the Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, we find two optical nuclei with a projection separation of 4.7…
We present high spatial resolution X-ray Chandra HRC and HST WFPC2 Halpha observations of the prototypical infrared luminous galaxy NGC6240. The central region of this system shows a remarkably complex morphology, with filaments and loops…
We present new HST NICMOS observations of NGC 4945, a starburst galaxy hosting a highly obscured active nucleus that is one of the brightest extragalactic sources at 100 keV. The HST data are complemented with ground based [FeII] line and…
We have discovered heavy obscuration in the dual active galactic nucleus (AGN) in the Swift/Burst Alert Telescope (BAT) source SWIFT J2028.5+2543 using Nuclear Spectroscopic Telescope Array (NuSTAR). While an early XMM-Newton study…
We present the first X-ray observations of three sources belonging to a new AGN class: the naked AGNs. Based on optical spectroscopic studies, these sources appear as classical type 2 (obscured) AGNs, with only narrow emission lines.…
We observed 7 INTEGRAL sources with the Chandra X-ray Observatory to refine their localization to ~2 arcsec and to study their X-ray spectra. Two sources are inferred to have a Galactic origin: IGR J08390-4833 is most likely a magnetic…
We present X-ray observations of the ultraluminous infrared galaxy, UGC 5101, thought to contain a buried active galactic nucleus (AGN) based on observations in other wavebands. We detected an absorbed hard component at >3 keV, as well as…
The Unification Model for active galactic nuclei posits that Seyfert 2s are intrinsically like Seyfert 1s, but that their broad-line regions (BLRs) are hidden from our view. A Seyfert 2 nucleus that truly lacked a BLR, instead of simply…
We present preliminary results of XMM-Newton observations of 5 Ultra-luminous Infrared Galaxies (ULIRGs), part of a mini-survey program dedicated to 10 ULIRGs selected from the bright IRAS sample. For 3 of them (IRAS 20551-4250, IRAS…
We present X-ray and optical analysis of 188 AGN identified from 497 hard X-ray (f (2.0-8.0 keV) > 2.7x10^-15 erg cm^-2 s^-1) sources in 20 Chandra fields (1.5 deg^2) forming part of the Chandra Multi-wavelength Project. These medium depth…
We present results on the Seyfert 2 galaxy NGC4388 in the Virgo cluster observed with ASCA during its PV phase. The 0.5-10 keV X-ray spectrum consists of multiple components; (1) a continuum component heavily absorbed by a column density NH…
AGN bubbles could play an important role in accelerating high-energy CRs and galactic feedback. Only in nearby galaxies could we have high enough angular resolution in multi-wavelengths to study the sub-kpc environment of the AGN, where the…
The ability to accurately discern active massive black holes (BHs) in nearby dwarf galaxies is paramount to understanding the origins and processes of "seed" BHs in the early Universe. We present Chandra X-ray Observatory observations of a…
A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects. We combine new…
We present new, deep Chandra X-ray and Giant Metrewave Radio Telescope 610~MHz observations of the spiral-galaxy-rich compact group HCG 16, which we use to examine nuclear activity, star formation and the high luminosity X-ray binary…
Reliably identifying active galactic nuclei (AGNs) in dwarf galaxies is key to understanding black hole demographics at low masses and constraining models for black hole seed formation. Here we present Chandra X-ray Observatory observations…
We present results from an XMM-Newton observation of the nearby Seyfert 2 galaxy NGC5643. The nucleus exhibits a very flat X-ray continuum above 2 keV, together with a prominent K-alpha fluorescent iron line. This indicates heavy…
We present $Chandra$ ACIS imaging spectroscopy of the nucleus of the Seyfert 2 Galaxy Mrk 34. We identify spatially and spectrally resolved features in the band that includes Fe K$\alpha$, Fe XXV and Fe XXVI. These features indicate…
We report the detection with Chandra of a Low-Luminosity AGN (LLAGN) in the Low Ionization Emission Line Region (LINER) hosted by Hydra A, a nearby (z=0.0537) powerful FRI radio galaxy with complex radio and optical morphology. In a 20 ks…