Search Publications
Ultraviolet spectral behavior of AO Psc and V1223 Sgr from the HST and IUE satellites
Sanad, M. R.
We present a spectroscopic study of two intermediate polar systems, AO Psc and V1223 Sgr observed with the Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) and International Ultraviolet Explorer (IUE) during the period 1980–2000. The reddening of two systems is determined from the 2200 Å feature. The ultraviolet emission line…
Black holes in 4 nearby radio galaxies
Cotter, Garret; Readhead, Tony; Durré, Mark +2 more
We study the velocity dispersion profiles of the nuclei of NGC 1326, 2685, 5273 and 5838 in the CO first overtone band. There is evidence for a black hole (BH) in NGC 1326 and 5838. Gas is seen flowing out of the nuclear region of NGC 5273. We put upper limits on the nuclear BHs responsible for its activity and that of NGC 2685.
The far-infrared properties of broad absorption line quasars from the Sloan Digital Sky Survey
Pu, Xingting
We present the results of a study which uses a sample of 320 Sloan Digital Sky Survey (SDSS) quasars with 1.68≤z≤2.28 inside the Herschel Stripe 82 Survey (HerS) region to compare the mid-infrared (MIR) and far-infrared (FIR) properties of broad absorption line (BAL) and non-BAL quasars. The BAL quasar sample comprises 56 high-ionization BAL (HiBA…
Dust in BL Lac objects and Fanaroff-Riley radio galaxies: infrared region
Seal Braun, P.
Here 28 BL Lac objects, 18 FR I type radio galaxies, 4 FR I/II type radio galaxies and 10 FR II type radio galaxies are studied from FIR (far infrared) to optical region (180 µm to 0.44 µm) to understand the nature of infrared emission from these objects and the physical properties of dust in the emitting region. Using the flux densiti…
Consistency relation for natural inflation with Planck 2015 data
Nozari, Kourosh; Kahvaee, H.; Rashidi, N.
We consider the cosine Natural inflation model that is a good candidate to explain the initial accelerating phase of the universe. By computing the inflationary parameters in Einstein frame, we construct a consistency relation between the scalar spectral index, tensor-to-scalar ratio, as well as the running of the scalar spectral index and compare…
Twisted Crab fingers revisited
Carlqvist, Per
Narrowband images of the Crab Nebula captured by the Hubble Space Telescope have earlier shown that the nebula does not only present a network of broad, bright filaments crossing the nebula but also numerous so-called fingers mostly pointing inwards. Using archival Hubble images we have in some detail studied the morphology of a great number of su…
WFPC2 UV survey of Galactic globular clusters. The Horizontal Branch temperature distribution
Dalessandro, E.; Salaris, M.; Lagioia, E. P. +2 more
Ultraviolet observations are the best tool to study hot stellar populations which emit most of their light at short wavelengths. As part of a large project devoted to the characterization of the UV properties of Galactic globular clusters (GGCs), we collected mid/far UV and optical images with the WFPC2@HST for 31 GGCs. These clusters cover a wide…
Constraining nonminimal DBI inflation with Planck2015 results
Asadi, Kosar; Nozari, Kourosh; Rashidi, Narges
We study cosmological inflation and perturbations in a nonminimally coupled Dirac-Born-Infeld setup in the light of the recent observational data reported by Planck collaboration. By adopting some important inflationary potentials, we analyze the scalar spectral index and the tensor-to-scalar ratio in confrontation with Planck 2015 data. In this m…
Ultraviolet spectroscopy of V Sagittae in high, intermediate and low states from HST and IUE satellites
Sanad, M. R.
We present the first phase resolved ultraviolet spectroscopic study of V Sge in high, intermediate and low states observed with the Hubble Space Telescope High Resolution Spectrograph (HST HRS) and International Ultraviolet Explorer (IUE) during the period 1978–1996 to diagnose the ultraviolet fluxes of C IV 1550 Å and He II 1640 Å emission lines …