Search Publications
UV surface brightness of galaxies from the local universe to z ~ 5
Scarpa, Riccardo; Falomo, Renato; Lerner, Eric J.
The Tolman test for surface brightness (SB) dimming was originally proposed as a test for the expansion of the universe. The test, which is independent of the details of the assumed cosmology, is based on comparisons of the SB of identical objects at different cosmological distances. Claims have been made that the Tolman test provides compelling e…
Modeling X-Ray Emission of a Straight Jet:. PKS 0920-397
Siemiginowska, A.; Birkinshaw, M.; Worrall, D. M. +14 more
We summarize a study of PKS 0920-397 using our 42 ks Chandra observation in conjunction with our ATCA 20GHz image, and HST/ACS F814W and F475W images. We investigate the hypothesis that the jet X-ray emission is due to inverse-Compton (IC) scattering on the cosmic microwave background (CMB) from the same population of relativistic electrons that g…
Emission from Large-Scale Jets in Quasars
Uchiyama, Yasunobu
We consider the emission processes in the large-scale jets of powerful quasars based on the results obtained with the VLA, Spitzer, Hubble, and Chandra. We show that two archetypal jets, 3C 273 and PKS 1136-135, have two distinct spectral components on large-scales: (1) the low-energy (LE) synchrotron spectrum extending from radio to infrared, and…
Do Recent Supernovae ia Observations Tend to Rule Out all the Cosmologies?
Vishwakarma, Ram Gopal
Dark energy and the accelerated expansion of the universe have been the direct predictions of the distant supernovae Ia observations which are also supported, indirectly, by the observations of the CMB anisotropies, gravitational lensing and the studies of galaxy clusters. Today these results are accommodated in what has become the concordance cos…
Constraints on Simplified Quartessence Cosmology from the Latest Observational Data
Wu, Puxun; Dong, Sumei
The simplified generalized Chaplygin gas (GCG) model as a candidate of UDME is studied in this paper. By using the latest 162 ESSENCE type Ia supernovae (Sne Ia) data, 30 high red shift Sne Ia data and the distance ratio from z = 0.35 to z = 1089 (the red shift of decoupling), we obtain Ω k = 0.076-0.077+0.093 and …