Search Publications
Black hole masses from reverberation mapping
Peterson, Bradley M.; Bentz, Misty C.
We review briefly how black hole masses are measured directly using reverberation mapping and indirectly through scaling relationships based on reverberation results, in particular through broad-line region radius-luminosity relationships. We discuss the nature and origin of uncertainties in these measurements, and outline current and future effor…
Stratification in the broad line region of AGN: The two-component model
Bon, E.; Popović, L. Č.; Ilić, D. +1 more
Here we present our investigation of the kinematic structure of the broad emission line region (BLR) in a sample of 14 single-peaked Active Galactic Nuclei (AGN), which have been previously observed in the X-ray (Fe Kα line) and where, according to the X-ray emission, a disk geometry is expected. To explain the BLR complex structure we apply a two…
QSO extended emission-line regions
Fu, Hai; Stockton, Alan; Canalizo, Gabriela
Extended emission-line regions (EELRs) on scales of a few tens of kpc are found around a substantial fraction of steep-spectrum radio-loud QSOs. In most cases, at least at low redshifts, the distribution of this gas seems to be uncorrelated with either the stellar distribution in the host galaxy or the radio structure. The origin of the gas and th…
Luminosity functions and star formation rates at z ∼ 6 10: Galaxy buildup in the reionization age
Bouwens, Rychard; Illingworth, Garth
HST ACS and NICMOS data are now of sufficient depth and areal coverage to place strong constraints on the formation and evolution of galaxies during the first 1-2 Gyrs of the universe. Of particular interest are galaxies at z ∼ 6 since they represent the earliest epoch accessible to current high-efficiency optical instrumentation. To this end, we …
Star forming galaxies at z ≈ 6 and reionization
Ellis, Richard; Bunker, Andrew; Lacy, Mark +3 more
We determine the abundance of i'-band drop-outs in the HST/ACS GOODS surveys and the Hubble Ultra Deep Field (UDF). The majority of these sources are likely to be z ≈ 6 galaxies whose flux decrement between the F775W i'-band and F850LP z'-band arises from Lyman- α absorption. We have shown with Keck/DEIMOS and Gemini/GMOS spectroscopy that this te…
An INTEGRAL/IBIS view of young Galactic SNRs through the 44Ti gamma-ray lines
Ballet, J.; Decourchelle, A.; Vink, J. +3 more
We present preliminary results of INTEGRAL/IBIS observations on Cas A, Tycho and Vela Junior supernova remnants in the line emission of 44Ti. This radioactive nucleus is thought to be exclusively produced in supernovae during the first stages of the explosion. It has a lifetime of about 87 yr and is then the best indicator of young SNRs…
Star formation in QSO host galaxies
Lacy, Mark; Stockton, Alan; Canalizo, Gabriela +1 more
Many of the conditions that are necessary for starbursts appear to be important in the triggering of QSOs. However, it is still debatable whether starbursts are ubiquitously present in galaxies harboring QSOs. In this paper we review our current knowledge from observations of the role of starbursts in different types of QSOs. Post-starburst stella…
Searching for the sources responsible for cosmic reionization: Probing the redshift range 7 < z < 10 and beyond
Stark, Daniel P.; Ellis, Richard S.
We review recent observations that suggest that the global star formation rate density of UV-bright galaxies is declining monotonically with redshift over 3 < z < 7 and illustrate the challenges that a continuation of this decline poses in explaining the assembled stellar mass in several z ∼ 6 galaxies deduced from recent Spitzer data. A pla…
Nucleosynthesis of 60Fe in massive stars
Limongi, Marco; Chieffi, Alessandro
We discuss certain aspects of the production of 60Fe in massive stars in the range between 11 and 120M⊙, both in the hydrostatic and explosive stages. We also compare the 60Fe/26Al γ-ray line flux ratio obtained in the present calculations to the detected value reported by INTEGRAL/SPI.
Measuring 26Al and 60Fe in the Galaxy
Diehl, Roland
With the SPI high-resolution spectrometer on INTEGRAL, new results have been obtained for long-lived radioactive 26Al and 60Fe in our Galaxy: 26Al sources apparently share the pattern of Galactic rotation in the inner Galaxy, and thus allow to estimate a total mass of 26Al in the Galaxy of 2.8M⊙