Related papers: Probing the Southern Fermi Bubble in Ultraviolet A…
We study a scenario in which the Fermi bubbles are formed through a Galactocentric outflow of gas and pre-accelerated cosmic-rays (CR). We take into account CR energy losses due to proton-proton interactions with the gas present in the…
The Fermi and eROSITA bubbles are giant gamma-ray and X-ray lobes in the Milky Way, extending up to $\sim$50{\deg} and ~$\sim$80{\deg} in galactic latitude, respectively, yet their origins remain debated. Using three-dimensional…
VLBI now has the capability of imaging relatively large fields-of-view (~ 5 arcmin sq) with sub-mJy detection limits. In principle such observations can distinguish between starburst and AGN activity in cosmologically distant sources. We…
As one of the most luminous radio-loud quasars showing intrinsic ultraviolet (UV) and X-ray absorption, 3C 351 provides a laboratory for studying the kinematics and physical conditions of such ionized absorbers. We present an analysis of…
We present a study of the intrinsic UV absorption and emission lines in an historically low-state spectrum of the Seyfert 1 galaxy NGC 5548, which we obtained in 2004 February at high spatial and spectral resolution with the Space Telescope…
Gamma-ray haloes can exist around galaxies due to the interaction of escaping galactic cosmic rays with the surrounding gas. We have searched for such a halo around the nearby giant spiral Andromeda galaxy M31 using almost 7 years of Fermi…
Narrow-Line Seyfert 1 (NLS1) Galaxies are an important type of active galactic nucleus (AGN), generally expected to be accreting at high Eddington rate. The properties of their outflows and importance of AGN feedback remain intriguing. We…
We construct a simple model of the star-formation- (and resultant supernova-) driven mass and energy flows through the inner ~200 pc (in diameter) of the Galaxy. Our modelling is constrained, in particular, by the non-thermal radio…
The nucleus of the Milky Way is known to harbour regions of intense star formation activity as well as a super-massive black hole. Recent Fermi space telescope observations have revealed regions of \gamma-ray emission reaching far above and…
Using hydrodynamical simulations, we show for the first time that an episode of star formation in the center of the Milky Way, with a star-formation-rate (SFR) $\sim 0.5$ M$_\odot$ yr$^{-1}$ for $\sim 30$ Myr, can produce bubbles that…
We analyze the correlation of the positions of gamma-ray sources in the Fermi Large Area Telescope First Source Catalog (1FGL) and the First LAT Active Galactic Nuclei (AGN) Catalog (1LAC) with the arrival directions of ultra-high-energy…
We study the possibility that the $\gamma$-ray loud active galactic nuclei (AGN) are the sources of ultra-high energy cosmic rays (UHECR), through the correlation analysis of their locations and the arrival directions of UHECR. We use the…
High quality infrared spectra of active galaxies including the stellar absorption features of Si at 1.59 um, CO(6,3) at 1.62 um, and CO(2,0) at 2.29 um are used to measure the stellar mass to light ratio at 1.65 um (M_H/L) and investigate…
Our view of the high velocity cloud (HVC) system is changing dramatically with new observations from the Far Ultraviolet Spectroscopic Explorer mission and the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. In…
We investigate the properties of the extinction curve in the rest-frame UV for a sample of 34 UV-luminous galaxies at 2 < z < 2.5, selected from the FORS Deep Field (FDF) spectroscopic survey. A new parametric description of the rest-frame…
Context: The origin of Galactic cosmic rays is still a mystery, in particular the sources and acceleration mechanism for cosmic rays with energies up to or beyond a PeV. Recently LHAASO has and H.E.S.S have shown that two gamma-ray sources…
The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) is a complete blind survey of the Virgo cluster covering about 40 sq. deg. in the far UV (FUV, lambda_eff=1539A, Delta-lambda=442A) and about 120 sq. deg. in the near UV (NUV,…
We present deep, wide-field European VLBI Network (EVN) 1.6 GHz observations of the Hubble Deep Field (HDF) region with a resolution of 0.025 arcseconds. Above the 210 microJy/beam (5sigma) detection level, the EVN clearly detects two radio…
The Fermi bubbles are one of the most remarkable features in the gamma-ray sky revealed by the Fermi Large Area Telescope (LAT). The nature of the gamma-ray emission and the origin of the bubbles are still open questions. In this note, we…
Observations of emission lines in Active Galactic Nuclei (AGN) often find fast (~1000 km s^-1) outflows extending to kiloparsec scales, seen in ionised, neutral atomic and molecular gas. In this work we present radiative transfer…