Related papers: Red quasars not so dusty
We examine the dust distribution around a sample of 70,000 low redshift galaxy groups and clusters derived from the Sloan Digital Sky Survey. By correlating spectroscopically identified background quasars with the galaxy groups we obtain…
We present additional evidence that dust is really forming along the red giant branch (RGB) of 47 Tuc at luminosities ranging from above the horizontal branch to the RGB-tip (Origlia et al. 2007). The presence of dust had been inferred from…
We present a method based on two broad-band colors to investigate the nature of the Extremely Red Objects (EROs), i.e., the galaxies selected to have very red optical-to-infrared colors. Dusty starburst and old ellipticals at redshifts…
We present multicolour images of the hosts of three z=2 QSOs previously detected in R-band by our group. The luminosities, colours and sizes of the hosts overlap with those of actively star-forming galaxies in the nearby Universe. Radial…
We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS…
We have observed the environments of a population of 33 heavily dust obscured, ultra-luminous, high-redshift galaxies, selected using WISE and NVSS at $z>$1.3 with the Infra-Red Array Camera on the $Spitzer$ Space Telescope over…
We constrain the light extinction properties of Milky Way dust. We investigated the correlations between dust column density as inferred from infrared data and the observed colours of celestial objects at cosmological distances with low…
We have assembled a large sample of 5996 quasars at redshift 2.0=< z <= 2.4 (high-z) or 0.7=< z <= 1.1 (low-z) from SDSS data release nine and seven quasar catalogs. The spectral energy distribution (SED) of quasars were constructed by…
Near-infrared surveys have revealed a substantial population of enigmatic faint galaxies with extremely red optical-to-near-infrared colours and with a sky surface density comparable to that of faint quasars. There are two scenarios for…
A database of radio-quiet quasars detected with ROSAT is presented containing 846 quasars seen in the All-Sky Survey and/or in pointed PSPC observations. About 70% of the objects have been detected in X-rays for the first time. We present…
We have discovered a concentration of extremely red objects (EROs; R-K>6) in the field of the z=2.69 quasar QSO 1213-0017 (UM 485), which is significantly overabundant compared to the field ERO surface density. The optical/near-IR colors of…
We report observations of a sample of high redshift sources (1.8<z<4.7), mainly radio-quiet quasars, at 350 microns using the SHARC bolometer camera at the Caltech Submillimeter Observatory. Nine sources were detected (>4-sigma) and upper…
Spectra of nearly 20000 point-like objects to a Galactic reddening corrected magnitude of i=19.1 have been obtained to test the completeness of the SDSS quasar survey. The spatially-unresolved objects were selected from all regions of color…
We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected…
We present results of the analysis of a sample of 22 stars of spectral types from O7 to B5 and luminosity classes I-V for which Spitzer/IRS spectra are available. The IRS spectra of these stars are examined for signs of excess infrared (IR)…
Almost 60% of the B2 low luminosity radio galaxies have been observed with the Hubble Space Telescope. We present an analysis of the dust features, which are often present in the form of circum-nuclear disks or lanes, and show that there…
We have derived the column densities of heavy elements in three gamma-ray burst (GRB) optical transients, associated with the circumburst or interstellar medium (ISM) of the host galaxy. In comparison with the same elements observed in…
We present a new population of z>2 dust-reddened, Type 1 quasars with 0.5<E(B-V)<1.5, selected using near infra-red (NIR) imaging data from the UKIDSS-LAS, ESO-VHS and WISE surveys. NIR spectra obtained using the Very Large Telescope (VLT)…
A substantial fraction of the stellar mass growth across cosmic time occurred within dust-enshrouded environments. Yet, the exact amount of star-forming activity that took place in high-redshift dusty galaxies currently missed by optical…
Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using IRAS data, and past studies have suggested a link between RGs with overabundant Li and IR excesses, implying the ejection of circumstellar shells or…