Related papers: Does the Milky Way Produce a Nuclear Galactic Wind…
Using high-resolution ultraviolet spectra obtained with the HST/Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer, we study the metallicity, kinematics, and distance of the gaseous "Outer Arm" (OA)…
Different physical processes in galaxy evolution, such as galaxy mergers that lead to coalescence of dual Active Galactic Nuclei (AGN) and outflows emanating from the narrow line region, can leave their imprint on the optical spectra of AGN…
We present a new measurement, 0.85-3.5 Z_solar, of the metallicity of high velocity cloud (HVC) Complex M by analyzing ultraviolet spectroscopic observations of the blazar Mrk 421 taken with the Cosmic Origins Spectrograph on the Hubble…
We present the first simultaneous detection of four distinct highly ionized $z=0$ absorbing phases using Chandra and XMM-Newton grating spectra toward the blazar PKS 2155$\hbox{-}$304. We detect the MgXII K$\alpha$ absorption line for the…
We have searched for evidence of soft X-ray absorption by hot metals in the vicinity of the Galaxy in the spectra of a small sample of fifteen Type I AGN observed with the high resolution X-ray gratings on board Chandra. This is an…
We present a novel absorption line survey using 54 blue horizontal branch stars (BHBs) in the Milky Way halo as background sources for detecting gas flows at the disk-halo interface. Distance measurements to high-latitude ($b$ > 60{\deg})…
The Galactic centre - as the closest galactic nucleus - holds both intrinsic interest and possibly represents a useful analogue to star-burst nuclei which we can observe with orders of magnitude finer detail than these external systems. The…
High-velocity clouds (HVCs) are multi-phase gas structures whose velocities (|v_LSR|>100 km/s) are too high to be explained by Galactic disk rotation. While large HVCs are well characterized, compact and small HVCs (with HI angular sizes of…
We present an analysis of the MgII 2796, 2803 and FeII 2586, 2600 absorption line profiles in individual spectra of 105 galaxies at 0.3<z<1.4. The galaxies, drawn from redshift surveys of the GOODS fields and the Extended Groth Strip, fully…
Galaxy-scale outflows, which are thought to provide the link connecting the central black hole to its host galaxy, are now starting to be observed. However, the physical origin of the mechanism driving the observed outflows, whether due to…
We study outflows driven by Active Galactic Nuclei (AGNs) using high- resolution simulations of idealized z=2 isolated disk galaxies. Episodic accretion events lead to outflows with velocities >1000 km/s and mass outflow rates up to the…
Active Galactic Nuclei (AGN) represent the growth phases of the supermassive black holes in the center of almost every galaxy. Powerful, highly ionized winds, with velocities $\sim 0.1- 0.2c$ are a common feature in X--ray spectra of…
Galactic outflows of molecular gas are a common occurrence in galaxies and may represent a mechanism by which galaxies self-regulate their growth, redistributing gas that could otherwise have formed stars. We previously presented the first…
We present medium resolution (R~20,000) HST/COS ultraviolet spectra covering 1155-1760 A of the Seyfert 1 Mrk 509 obtained simultaneously with a Chandra/LETGS spectrum as part of a multiwavelength campaign in 2009 that included observations…
Three recent surveys of 21-cm line emission in the Galactic plane, combining single dish and interferometer observations to achieve resolution of 1 arcmin to 2 arcmin, 1 km/s, and good brightness sensitivity, have provided some 650…
We demonstrate that our Galactic Center, despite little evidence for the presence of a currently active nucleus, provides insight into the feeding of AGN: The observed velocity field of molecular clouds can be interpreted as tracing out the…
During the last decade, wide-angle powerful outflows from AGN, both on parsec and kpc scales, have been detected in many galaxies. These outflows are widely suspected to be responsible for sweeping galaxies clear of their gas. We present…
Cold, neutral interstellar gas, the reservoir for star formation, is traced through the absorption of the 21-centimetre continuum radiation by neutral hydrogen (HI). Although detected in one hundred cases in the host galaxies of distant…
Galactic outflows provide important feedback effects to regulate the evolution of host galaxies. Two primary diagnostics of outflows are broad and/or blueshifted emission and absorption lines. Even though well-established methods exist to…
Post-starburst (PSB) galaxies may be in rapid transition from star-forming to quiescence and are excellent candidates to constrain active galactic nuclei (AGN) feedback models. We study galactic winds in the stacked spectrum of 560 AGN PSBs…