منابع مشابه
Dust emission from the most distant quasars
We report observations of three SDSS z > 6 QSOs at 250 GHz (1.2 mm) using the 117-channel MaxPlanck Millimeter Bolometer (MAMBO-2) array at the IRAM 30-meter telescope. J1148+5251 (z = 6.41) and J1048+4637 (z = 6.23) were detected with 250 GHz flux densities of 5.0±0.6mJy and 3.0±0.4 mJy, respectively. J1630+4012 (z = 6.05) was not detected with a 3σ upper limit of 1.8 mJy. Upper flux density l...
متن کاملOn the detectability of distant Compton-thick obscured quasars
Chandra and XMM–Newton have resolved the 2–8 keV X-ray Background (XRB) into point sources. Many of the fainter sources are obscured active galactic nuclei (AGN) with column densities in the range of 10 − 10 cm−2 , some of which have quasar-like luminosities. According to obscuration models, the XRB above 8 keV is dominated by emission from Comptonthick AGN, with column densities exceeding 1.5 ...
متن کاملMicrolensing for distant quasars with the space interferometer Radioastron
It is well-known that gravitational lensing is a powerful tool to investigate matter distributions including DM. Typical angular distances images and typical time scales depend on gravitational lens masses. A launch of space interferometer Radioastron will give new excellent facilities to investigate microlensing in radio band, since in this case there is a possibility not only to resolve micro...
متن کاملExtreme gas properties in the most distant quasars
We present near-IR, low resolution spectra of eight of the most distant quasars known, with redshifts in the range 4.9<z<6.4. Half of these quasars are characterized by deep, broad and blueshifted absorption features associated with both high and low ionization species (CIV, SiIV, AlIII, MgII), i.e. they belong to the class of Broad Absorption Line (BAL) quasars, which are associated with power...
متن کاملFinding the most distant quasars using Bayesian selection methods
Quasars, the brightly glowing disks of material that can form around the super-massive black holes at the centres of large galaxies, are amongst the most luminous astronomical objects known and so can be seen at great distances. The most distant known quasars are seen as they were when the Universe was less than a billion years old (i.e., ∼ 7% of its current age). Such distant quasars are, howe...
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ژورنال
عنوان ژورنال: Nature
سال: 1987
ISSN: 0028-0836,1476-4687
DOI: 10.1038/330426a0