Related papers: Anionic hydrogen clusters as a source of diffuse i…

Hydrocarbons are ubiquitous in the interstellar medium, observed in diverse environments ranging from diffuse to molecular dark clouds and strong photon-dominated regions near HII regions. Recently, two broad diffuse interstellar bands…

The diffuse interstellar bands (DIBs) are absorption lines observed in visual and near infrared spectra of stars. Understanding their origin in the interstellar medium (ISM) is one of the oldest problems in astronomical spectroscopy, as…

Echelle spectra of the double-lined spectroscopic binary HD 204827 were obtained on five nights, at a resolving power R = 38,000 and with a S/N ratio = 750 near 6000 A in the final, combined spectrum. The stars show E(B-V) = 1.11 and…

We derive the atomic hydrogen content for a total of 1900 spirals in the fields of eighteen nearby clusters. By comparing the HI deficiency distributions of the galaxies inside of and outside of one Abell radius of each cluster, we find…

We have conducted a high signal-to-noise spectroscopic survey of 670 nearby early-type stars, to map Diffuse Interstellar Band (DIB) absorption in and around the Local Bubble. The project started with a Southern hemisphere survey conducted…

Diffuse interstellar bands comprise hundreds of absorption features in the ISM. Most DIBs are observed in the optical, but some are in the IR. We observed 76 early-type stars at R=50,000 and S/N ratios of several hundreds using CRIRES. We…

Ever since their first detection over 100 years ago, the mysterious diffuse interstellar bands (DIBs), a set of several hundred broad absorption features seen against distant stars in the optical and near infrared wavelength range, largely…

We report R~3000 VLT ISAAC K-band spectroscopy of the nuclei (i.e. central 100-300pc) of 9 galaxies hosting an active galactic nucleus. For 5 of these we also present spectra of the circumnuclear region out to 1kpc. We have measured a…

A previous article argued that the antagonism between sight-lines with and without a bump at 2200 \AA\ disappears, and that the observed properties of interstellar extinction can be globally understood, if it is accepted that scattered…

We have searched for diffuse intracluster light in the galaxy cluster Abell 2667 (z=0.233) from HST images in three filters. We have applied to these images an iterative multi-scale wavelet analysis and reconstruction technique, which…

Infrared spectra of hydrocarbon dust absorption bands toward the bright hypergiant Cygnus OB2-12 are compared to published spectra of the Quintuplet Cluster, a sightline to the Galactic center. The Cyg OB2-12 data include a new ground-based…

Most of the baryons in the present-day universe are thought to reside in intergalactic space at temperatures of 10^5-10^7 K. X-ray emission from these baryons contributes a modest (~10%) fraction of the ~ 1 keV background whose prominence…

We report high resolution spectroscopy of the moderately reddened (A$_V$=3) early type star Cernis 52 located in a region of the Perseus molecular cloud complex with anomalous microwave emission. In addition to the presence of the most…

We present narrow- and medium-band HST imaging, with additional supporting ground-based data, for 8 galaxies identified as hosting fading AGN. These have AGN-ionized gas projected >10 kpc from the nucleus, and significant shortfall of…

NGC1275, the central galaxy in the Perseus cluster, is the host of gigantic hot bipolar bubbles inflated by AGN jets observed in the radio as Perseus A. It presents a spectacular $H{\alpha}$-emitting nebulosity surrounding NGC1275, with…

We have detected a broad interstellar absorption band centred close to 7700 \r{A} and with a FWHM of 176.6$\pm$3.9 \r{A}. This is the first such absorption band detected in the optical range and is significantly wider than the numerous…

Interstellar absorption lines up to J"=10 in the (2,0) band and up to J"=6 in the (3,0) band of the C$_2$ $A^1\Pi_u$ - $X^1\Sigma^+_g$ system are detected toward star Cernis 52 (BD+31$^o$ 640) in the Perseus molecular complex. The star lies…

From the structure of PHL 293B and the physical properties of its ionizing cluster and based on results of hydrodynamic models, we point at the various events required to explain in detail the emission and absorption components seen in its…

The Sun lies in the middle of an enormous cavity of a million degree gas, known as the Local Bubble. The Local Bubble is surrounded by a wall of denser neutral and ionized gas. The Local Bubble extends around 100 pc in the plane of Galaxy…

We present high-resolution UV spectra of absorption-line systems toward the low-z QSO HS0624+6907 (z=0.3700). Coupled with spectroscopic galaxy redshifts, we find that many of these absorbers are integalactic gas clouds distributed within…