Results 31 to 40 of about 18,958 (240)
Joint formation of QSOs and spheroids: QSOs as clocks of star formation in spheroids [PDF]
Monthly Notices of the Royal Astronomical Society, 2001 13 pages, 8 figures, accepted by MNRAS, major revision of the ...
Granato GL +6 more
openaire +5 more sources
Journal of Advanced Transportation, Volume 2021, Issue 1, 2021., 2021 The timetabling problem (TTP) and vehicle scheduling problem (VSP) are two indispensable problems in public transit planning process. They used to be solved in sequence; hence, optimality of resulting solutions is compromised. To get better results, some integrated approaches emerge to solve the TTP and VSP as an integrated problem.
Yindong Shen +3 more
wiley +1 more source
On the Nature of Soft X-ray Weak Quasi-Stellar Objects [PDF]
, 1999 Recent studies of QSOs with ROSAT suggest the existence of a significant population of Soft X-ray Weak QSOs (SXW QSOs) where the soft X-ray flux is ~ 10-30 times smaller than in typical QSOs.
A. Laor +16 more
core +3 more sources
The Astronomical Journal, 2023 The Star Formation Across Cosmic Time (SFACT) survey is a new narrowband survey designed to detect emission-line galaxies (ELGs) and quasi-stellar objects (QSOs) over a wide range of redshifts in discrete redshift windows.
David J. Carr +4 more
doaj +1 more source
QSOs Associated with M82 [PDF]
The Astrophysical Journal, 2003 The starburst / AGN galaxy M82 was studied by Dahlem, Weaver and Heckman using X-ray data from ROSAT and ASCA, as part of their X-ray survey of edge-on starburst galaxies. They found seventeen unresolved hard-X-ray sources around M82, in addition to its strong nuclear source, and other X-rays within the main body of M82.
G. Burbridge +3 more
openaire +3 more sources
Eddington Accretion and QSO Emission Lines at z ~ 2 [PDF]
, 2003 Broad Absorption Line (BAL) QSOs have been suggested to be youthful super-accretors based on their powerful radiatively driven absorbing outflows and often reddened continua. To test this hypothesis, we observed near IR spectra of the H$\beta$ region for
Beverley J. Wills +5 more
core +2 more sources
Crossing the Rubicon of Reionization with z ∼ 5 QSOs
The Astrophysical Journal, 2023 One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High- z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high- z ...
Andrea Grazian +14 more
doaj +1 more source
The Astrophysical Journal, 2002 In the Chandra Deep Field South 1Msec exposure we have found, at redshift 3.700 +- 0.005, the most distant Type 2 AGN ever detected. It is the source with the hardest X-ray spectrum with redshift z>3. The optical spectrum has no detected continuum emission to a 3sigma detection limit of ~3 10^{-19} ergs/s/cm^2/AA and shows narrow lines of Ly_alpha ...
Anton M. Koekemoer +20 more
openaire +5 more sources
Polarization of Broad Absorption Line QSOs I. A Spectropolarimetric Atlas [PDF]
, 1999 We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission line polarization of BAL QSOs yield clues about their structure.
A. R. Martel +11 more
core +3 more sources
QSO winds and galaxy evolution [PDF]
AIP Conference Proceedings, 2010 There exists a population of broad-line z∼2 QSOs which have heavily absorbed X-ray spectra. These objects constitute ∼10% of the population at luminosities and redshifts characteristic of the main producers of QSO luminosity in the Universe. Our follow up observations in the submm show that these QSOs are often embedded in ultraluminous starburst ...
M. J. Page +5 more
openaire +3 more sources